Process cartridge mounting mechanism, electrophotographic image forming apparatus, and process cartridge

[0002] The present invention relates to a process-cartridge mounting mechanism, an electrophotographic image forming apparatus and a process cartridge.

[0003] Here, the electrophotographic image forming apparatus is an apparatus which forms an image on recording materials through an electrophotographic image formation process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, an LED printer or the like), a facsimile machine and a word processor.

[0004] The process cartridge is a cartridge that contains as a unit an electrophotographic photosensitive member and a charging means, a developing means or a cleaning means in the form of a cartridge which is detachably mountable to a main assembly of an image forming apparatus. The process cartridge may contain an electrophotographic photosensitive member and at least one of a charging means, a developing means, and a cleaning means in the form of a cartridge which is detachably mountably to a main assembly of an image forming apparatus. The process cartridge may contain an electrophotographic photosensitive member and at least developing means in the form of a cartridge which is detachably mountably to a main assembly of an image forming apparatus.

[0005] Such a process-cartridge type is conventionally used. With this process-cartridge type, the maintenance of the apparatus can be carried out in effect by the user without a service person, so that operability is remarkably good. For this reason, the process-cartridge type is widely used in the field of image forming apparatus.

[0006] In order to provide good images in such an electrophotographic image forming apparatus using a process cartridge, the process cartridge is desirably mounted correctly at a predetermined position in the main assembly of the electrophotographic image forming apparatus, and the interface portions thereof, such as various electrical contacts and the drive transmitting mechanisms, are correctly connected.

[0007] Referring first to FIGS. 23 to 25, there is shown an example to accomplish these goals wherein for the mounting-and-demounting of a process cartridge CR relative to the main assembly P of the image forming apparatus, a positioning boss CB is provided coaxially with the photosensitive drum in the process cartridge CR, and a guide GL for guiding and positioning the positioning boss CB is provided in the main assembly P of the image forming apparatus. When the operator inserts the cartridge CR along the mounting guide GL to the predetermined position, the fixing member (unshown) provided in the main assembly P of the apparatus contacts to the cartridge CR, and the rotation thereof around the positioning boss CB is prevented, as is known.

[0008] Additionally, it is also known that cover member C of the main assembly P of the apparatus is provided with a spring for urging the cartridge CR mounted in the main assembly P in the mounting direction.

[0009] It is also known that back cover UC (FIG. 25) is provided inside the cover member C, and by closing the cover member C, the cartridge CR is pushed into the regular position.

[0010] The present invention is intended to provide a further development in this area.

[0011] Accordingly, it is a principal object of the present invention to provide a process-cartridge mounting mechanism, a process-cartridge mounting method, a process cartridge, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, wherein the mounting operability at the time of mounting the process cartridge to the main assembly of the apparatus is improved.

[0012] It is another object of the present invention to provide a process-cartridge mounting mechanism, a process-cartridge mounting method, a process cartridge, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, ,wherein the process cartridge can be substantially automatically mounted to a mounting position in the main assembly of the apparatus.

[0013] It is a further object of the present invention to provide a process-cartridge mounting mechanism, a process-cartridge mounting method, a process cartridge, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, wherein the process cartridge can be mounted to the mounting position of the main assembly of the apparatus in interrelation with a closing operation of the cover member.

[0014] It is a further object of the present invention to provide a process-cartridge mounting mechanism, a process-cartridge mounting method, a process cartridge, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, wherein the process cartridge can be automatically mounted to or demounted from the mounting position of the main assembly of the apparatus.

[0015] It is a further object of the present invention to provide a process-cartridge mounting mechanism, a process-cartridge mounting method, a process cartridge, and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, wherein the mounting-and-demounting operability, relative to the main assembly of the apparatus, of the process cartridge is improved.

[0016] According to an aspect of the present invention, there is provided a process-cartridge mounting mechanism for mounting a process cartridge to a mounting position in a main assembly of an electrophotographic image forming apparatus. The cartridge comprises an electrophotographic photosensitive member and process means actable on the photosensitive member. The process cartridge mounting mechanism comprises: an openable cover member mounted to the main assembly of the apparatus, the cover member being opened and closed when the cartridge is mounted to or demounted from the main assembly of the apparatus; a first main assembly side guide, which is provided in the main assembly of the apparatus and which is movable in interrelation with opening and closing operation of the cover member, the first main assembly side guide including a first supporting portion and a first urging portion; a second main assembly side guide, which is provided in the main assembly of the apparatus and which is movable in interrelation with the opening and closing operation of the cover member, the second main assembly side guide including a second supporting portion and a second urging portion; a first cartridge guide, provided in the cartridge at one longitudinal end of a cartridge frame, for guiding the cartridge toward the mounting position, the first cartridge guide including a first supported portion to be supported on the first supporting portion and a first urged portion to be urged to the first urging portion; and a second cartridge guide, provided in the cartridge at one longitudinal end of the cartridge frame, for guiding the cartridge toward the mounting position, the second cartridge guide including a second supported portion to be supported on the second supporting portion and a second urged portion to be urged to the second urging portion. The cartridge is mounted to the mounting position in interrelation with a closing operation of the cover member.

[0017] According to another aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image of a recording material, to which a process cartridge is detachably mountable. The apparatus comprises: (a) an openable cover member mounted to the main assembly of the apparatus, the cover member being opened and closed when the cartridge is mounted to or demounted from the main assembly of the apparatus; (b) a first main assembly side guide which is provided in the main assembly of the apparatus and which is movable in interrelation with opening and closing operation of the cover member, the first main assembly side guide including a first supporting portion and a first urging portion; (c) a second main assembly side guide, which is provided in the main assembly of the apparatus and which is movable in interrelation with the opening and closing operation of the cover member, the second main assembly side guide including a second supporting portion and a second urging portion; and (d) mounting means for mounting a process cartridge. The process cartridge includes: process means actable on the electrophotographic photosensitive member; a first cartridge guide, provided in the cartridge at one longitudinal end of a cartridge frame, for guiding the cartridge toward the mounting position, the first cartridge guide including a first supported portion to be supported on the first supporting portion and a first urged portion to be urged to the first urging portion; a second cartridge guide, provided in the cartridge at one longitudinal end of the cartridge frame, for guiding the cartridge toward the mounting position, the second cartridge guide including a second supported portion to be supported on the second supporting portion and a second urged portion to be urged to the second urging portion. The cartridge is mounted to the mounting position in interrelation with a closing operation of the cover member.

[0018] According to a further aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus for forming an image on a recording material. The image forming apparatus includes an openable cover member mounted to the main assembly of the apparatus. The cover member is opened and closed when the cartridge is mounted to or demounted from the main assembly of the apparatus. The apparatus also includes a first main assembly side guide, which is provided in the main assembly of the apparatus and which is movable in interrelation with the opening and closing operation of the cover member. The first main assembly side guide includes a first supporting portion and a first urging portion. The apparatus further includes a second main assembly side guide, which is provided in the main assembly of the apparatus and which is movable in interrelation with the opening and closing operation of the cover member. The second main assembly side guide includes a second supporting portion and a second urging portion. The apparatus also includes an electrophotographic photosensitive member, process means actable on the photosensitive member; a cartridge frame, and a first cartridge guide, provided in the cartridge at one longitudinal end of a cartridge frame, for guiding the cartridge toward the mounting position. The first cartridge guide includes a first supported portion to be supported on the first supporting portion and a first urged portion to be urged to the first urging portion. In addition, the apparatus comprises a second cartridge guide, provided in the cartridge at one longitudinal end of the cartridge frame, for guiding the cartridge toward the mounting position, the second cartridge guide including a second supported portion to be supported on the second supporting portion and a second urged portion to be urged to the second urging portion. The cartridge is mounted to the mounting position in interrelation with a closing operation of the cover member. According to this invention, the process cartridge can be moved toward the mounting position by the first main assembly side guide and the second main assembly side guide, and is movable in interrelation with the opening and closing operation of an opening and closing member or a cover member.

[0019] These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following invention taken in conjunction with the accompanying drawings.

[0020] These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

[0021] FIG. 1 is a schematic sectional view of an electrophotographic image forming apparatus.

[0022] FIG. 2 is a schematic sectional view of a process cartridge.

[0023] FIG. 3 is a perspective view of a process cartridge mounting-and-demounting mechanism according to an embodiment of the present invention.

[0024] FIG. 4 is a perspective view of a process cartridge.

[0025] FIG. 5 is an exploded perspective view of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0026] FIG. 6 is an illustration of a cartridge guide and a positioning portion at the right side of the process cartridge.

[0027] FIG. 7 is an illustration of a cartridge guide and a positioning portion at the left side of the process cartridge.

[0028] FIG. 8 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0029] FIG. 9 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0030] FIG. 10 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0031] FIG. 11 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0032] FIG. 12 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 3.

[0033] FIG. 13 illustrates a floating right side cartridge guide of the process cartridge away from the main-assembly-side guide when the process cartridge is mounted to the main assembly of the image forming apparatus.

[0034] FIG. 14 illustrates a floating left side cartridge guide of the process cartridge away from the main-assembly-side guide when the process cartridge is mounted to the main assembly of the image forming apparatus.

[0035] FIG. 15 is an exploded perspective view of a process cartridge mounting-and-demounting mechanism according to another embodiment of the present invention.

[0036] FIG. 16 is an exploded perspective view of a process cartridge mounting-and-demounting mechanism according to a further embodiment of the present invention.

[0037] FIG. 17 is an illustration of an operation of a process cartridge mounting-and-demounting mechanism shown in FIG. 13.

[0038] FIG. 18 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 13.

[0039] FIG. 19 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 13.

[0040] FIG. 20 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 13.

[0041] FIG. 21 is an illustration of an operation of the process cartridge mounting-and-demounting mechanism shown in FIG. 13.

[0042] FIG. 22 is an illustration of a positioning guide according to another embodiment of the present invention.

[0043] FIG. 23 is a perspective view of a process cartridge detachably mountable to a cartridge mounting guide of a main assembly of a conventional electrophotographic image forming apparatus.

[0044] FIG. 24 is an illustration of a cartridge mounting guide of a main assembly of a conventional electrophotographic image forming apparatus.

[0045] FIG. 25 is an illustration of a back cover and a cartridge mounting guide of a main assembly of a conventional electrophotographic image forming apparatus.

[0046] The preferred embodiments will be described in conjunction with the accompanying drawings.

[0047] In the following descriptions, the longitudinal direction of the process cartridge is a direction which crosses (substantially perpendicular to) the mounting-and-demounting direction of the process cartridge relative to the main assembly of the apparatus and which is parallel with the surface of the recording material and crosses (substantially perpendicular to) a feeding direction of the recording material. As regards the process cartridge and the main assembly of the apparatus, “left and right” is as seen from above the recording medium in the feeding direction of the recording material, and in the specification “right” is called “first”, and “left” is called “second”. In the process cartridge, the “upper surface” of the process cartridge is a surface which takes an upper position when the process cartridge is mounted to the main assembly of the apparatus, and the “lower surface” is a surface which takes a lower position when the process cartridge is mounted to the main assembly of apparatus.

[0048] A description will be provided as to an embodiment of the present in conjunction with the accompanying drawings.

[0049] In this embodiment, the process cartridge is mounted to a cartridge-mounting-portion material of the main assembly through an opening of a mounting-and-demounting mechanism of the electrophotographic image forming apparatus when an opening and closing member is in an opening position.

[0050] In a first half of the closing operation of the opening and closing member from a full opening state, a holding means for holding a mounting member moves the cartridge-mounting-portion material from a first position at which the process cartridge is detachably mountable to a second position at which the process cartridge is operable for image formation. In the latter half of an opening operation from a full-close position, the holding means moves the cartridge mounting portion material from the second position to the first position. By doing so, the process cartridge can be mounted to and demounted from the main assembly of the apparatus in interrelation with the opening and closing operation of the opening and closing member of the process cartridge.

[0051] Referring to FIGS. 1 and 2, the process cartridge and the electrophotographic image forming apparatus to which the process cartridge is detachably mountable will be described. FIG. 1 shows a general arrangement of the electrophotographic image forming apparatus to which the process cartridge is mounted, and FIG. 2 is a schematic illustration of the process cartridge.

[0052] The general arrangement of the process cartridge and the electrophotographic image forming apparatus will first be described, and the structure of the process cartridge mounting-and-demounting mechanism for the mounting and demounting of the process cartridge relative to the main assembly of the electrophotographic image forming apparatus, will be described.

[0053] (General Arrangement)

[0054] As shown in FIG. 1, in the electrophotographic image forming apparatus (laser beam printer, image forming apparatus), an information light modulated in accordance with image information is applied to the electrophotographic photosensitive member (photosensitive drum) 7 from an optical system 1 as optical means to form an electrostatic latent image on the photosensitive drum 7, and the electrostatic latent image is developed with developer (toner) into a toner image (visualized image). In synchronization with the formation of the toner image, a recording material (recording paper, an OHP sheet, a textile or the like) 2 is fed out of a cassette 3aby a pick-up roller 3band a press-contact member 3cpress-contacted thereto, and then the recording material is fed by registration rollers 3e. The toner image formed on the photosensitive drum 7 of the process cartridge B is transferred onto the recording material 2 by voltage application to the transfer roller 4 as transferring means. The recording material 2 is fed to fixing means 5 along a feeding guide 3f. The fixing means 5 contains therein a driving roller 5aand a fixing rotatable member 5dincluding a cylindrical sheet rotatably supported by a supporting member 5cand a heater 5bherein. It applies heat and pressure to the recording material 2 passing therethrough to fix the transferred toner image. The recording material 2 is further fed by a pair of discharging rollers 3gand 3h, and is discharged to a discharging portion 6 by way of a reverse feeding path. In this embodiment, the feeding means 3 is constituted by the pick-up roller 3b, the press-contact member 3c, the registration roller 3e, and so on.

[0055] (Process Cartridge)

[0056] On the other hand, the process cartridge B contains the electrophotographic photosensitive member and at least one process means. The process means may be charging means for charging the electrophotographic photosensitive member, developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member, cleaning means for removing the toner remaining on the electrophotographic photosensitive member, or the like. As shown in FIG. 2, in the process cartridge B of this embodiment, the photosensitive drum 7, which is an electrophotographic photosensitive member having a photosensitive layer, is rotated, and a voltage is applied to a charging roller 8, which is charging means to uniformly charge the surface of the photosensitive drum 7. The photosensitive drum 7 thus charged is exposed to information light (light image) modulated in accordance with image information emitted from the optical system 1 through an exposure opening 9 so that an electrostatic latent image is formed on the photosensitive drum, and the electrostatic latent image is developed by developing means 10.

[0057] The developing means 10 feeds the toner in the toner accommodating portion 10aby a rotatable first feeding member 10b2 and a second feeding member 10b1, which are toner feeding means. A developing roller 10d,which is a development rotatable member (developer carrying member) containing therein a fixed magnet 10c,is rotated, and a toner layer having a triboelectric charge is formed on the surface of the developing roller 10dby a developing blade 10e, and the toner is moved onto the photosensitive drum 7 in accordance with the electrostatic latent image, by which the toner image is developed into a visualized image.

[0058] The toner image is transferred onto the recording material 2 by the application of the voltage having an opposite polarity from the toner image to the transfer roller 4. Thereafter, the toner remaining on the photosensitive drum 7 is scrapped by a cleaning blade 11a, and the removed toner is received by a receptor sheet 11b, and cleaning means 11 for collecting the removed toner into a removed toner accommodating portion 11cremoves the residual toner from the photosensitive drum 7.

[0059] The process cartridge B of this embodiment includes a cleaning frame 13 supporting the rotatably supported photosensitive drum 7, the cleaning means 11, and the charging roller 8, and a toner developing device frame 12 supporting the developing means 10 and the toner accommodating portion 10a. The toner developing device frame 12 is supported for rotation relative to the cleaning frame 13 so that the developing roller 10dof the developing means 10 can be opposed in parallel to the photosensitive drum 7 with a predetermined clearance therebetween, and spacers for maintaining a gap between the developing roller 10dand the photosensitive drum 7 with a predetermined pressure.

[0060] The photosensitive drum 7, the charging roller 8, the developing roller 10d, the cleaning blade 11a,and so on are accommodated in a cartridge frame (cartridge frame) CF provided by connecting the cleaning frame 13 and the toner developing device frame 12 which is integrated by welding the developing device frame 12a, the lower frame 12band the cap member 12c, into a form of a cartridge, and the cartridge is detachably mountable to the main assembly of the electrophotographic image forming apparatus 14 in the direction of arrow X.

[0061] (Mounting-and-demounting Mechanism for Process Cartridge)

[0062] Referring to FIGS. 3 and 7, a description will be provided as to a process cartridge mounting-and-demounting mechanism for mounting the process cartridge B to the main assembly 14 of the image forming apparatus and demounting of the process cartridge B from the main assembly 14.

[0063] FIG. 3 is a perspective view of a process cartridge mounting-and-demounting mechanism as seen from the righthand side in the mounting direction of the process cartridge; FIG. 4 is a perspective view of the process cartridge; FIG. 5 is an exploded perspective view of a process cartridge mounting-and-demounting mechanism shown in FIG. 3; FIG. 6 is an illustration of a cartridge guide provided at the right side of the process cartridge and a positioning portion; and FIG. 7 is an illustration of a cartridge guide provided at the left side of the process cartridge and a positioning portion.

[0064] The mounting and demounting of the process cartridge B is carried out by opening the opening and closing member (opening cover) 15 as shown in FIG. 3. When the member 15 is opened, an opening W for permitting mounting and demounting of the process cartridge B is exposed. The opening W is defined by a front plate 43 extended in the longitudinal direction of the process cartridge B and first and second fixed members of a main assembly (left and right inner plates) 40, which are side plates opposed to each other in the longitudinal direction (the direction of the axis of the photosensitive drum 7) of the process cartridge B in the main assembly 14 of the image forming apparatus. The opening W is large enough to permit mounting of the process cartridge B from the cleaning frame 13 in a direction of arrow X. On the inner surfaces of the first and second fixed members of the main assembly 40 (left and right), there are provided first and second main-assembly-side guides (mounting-and-demounting guides) 41 functioning as cartridge-mounting-portion materials, and front guides 42 functioning as entrance guides, and they are symmetrically disposed, respectively.

[0065] The first and second main-assembly-side guides 41 are provided with guide grooves 41afunctioning as guide portions on the surfaces defining the opening W. The guide grooves 41aare inclined downwardly toward the inside of the apparatus to facilitate mounting of the cartridge B in a direction crossing the feeding direction of the recording material 2. The first and second cartridge guides (guiding ribs) of the cartridge B (portions to be guided) 18b, when the cartridge B is mounted through the opening W, are engaged into the guide grooves 41aof the main-assembly-side guide 41. By this, the guide 41 holds the process cartridge B. The main-assembly-side guide 41 includes a recess 41a1 at a trailing edge of the guide groove 41a, and the projection 18b1 at the front end of the cartridge guide 18bis easily engaged into the recess 41a1. By doing so, the guide 41 holds the process cartridge B stationarily. In each of the first and second main-assembly-side guides 41, designated by a are first and second supporting portions, designated by b are first and second urging portions, and designated by c are guide regulating portions.

[0066] The front guide 42 is disposed upstream of the main assembly side guide 41 in the mounting direction X of the cartridge B. It is provided with a guide groove 42a,which is continuous with the guide groove 41aof the main-assembly-side guide 41 in the mounting direction X of the process cartridge B, in a side facing the opening W. The front guide 42, when the process cartridge B is inserted through the opening W, functions to guide the cartridge guide 18bof the cartridge B into the guide groove 42a. In this manner, the guide 42 guides the process cartridge B into the main-assembly-side guide 41.

[0067] A front plate 43 is disposed downstream of the opening W. It is provided on an upper surface facing the opening W with an inclined surface 43ahaving an inclination substantially equal to the inclination of the guide grooves 41a, 42aof the main-assembly-side guide 41 and the front guide 42.

[0068] A transfer roller 4 is disposed at a rear side in the mounting direction X of the cartridge B toward the main assembly 14 of the apparatus. Above a neighborhood of the axial end of the transfer roller 4, there is provided a positioning guide 44 for correctly positioning and supporting the cartridge B at an image-forming-operation position of the cartridge B (mounting completion position (second position)). The positioning guide 44 is fixed to the first or second fixed member of the main assembly 40 of the main assembly 14 of the apparatus. The guide 44 includes first and second main-assembly-side positioning portions 44awhich are engageable with first and second positioning portions (positioning bosses) 18aof the cartridge B, which will be described hereinafter, and first and second regulating portions of the main assembly (projections) 44bentering a movement locus of the positioning portions 18atoward the main-assembly-side positioning portions 44a. Designated by g is a positioning-portion-entrance opening of the main-assembly-side positioning portion 44a. The regulating portion 44bof the main assembly is disposed upstream of the movement locus of the cartridge B toward the image-forming-operation position, that is, upstream of the main-assembly-side positioning portion 44 with respect to a moving direction from the first position to the second position of the main-assembly-side guide 41. The regulating portion 44bhas a height so that the positioning portion 18aabuts it and rides over it.

[0069] As shown in FIG. 5, the main-assembly-side guide 41 has a first engaging member (projected guide) (boss) 41cand a second engaging member (boss) 41bon the side opposite from the guide groove 41a. The second engaging member 41bis disposed downstream of the guide groove 41ain the mounting direction X of the cartridge B. The first engaging member 41cis disposed upstream of the guide groove 41ain the mounting direction X of the cartridge B. The first engaging member 41cis taller than the second engaging member 41b. At the front end of the second engaging member 41b, there is provided a projection 41eprojected in the radial direction of the engaging member 41b. At the front end of the first engaging member 41c, there is provided a snap fitting claw 41dwhich is capable of elastic deformation in the radial direction of the engaging member 41c.

[0070] The fixed member 40 of the main assembly 14 is provided with two guiding rails 40a, 40bfunctioning as holding means for the mounting member, for slidable engagement with the engaging members 41b, 41cof the main-assembly-side guide 41, independently from each other. The widths of the guiding rails 40a, 40b(inner diameters measured along the short sides are equal to or slightly larger than the diameters of the engaging members 41b, 41c. The main-assembly-side guide 41 is moved between the optical system 1 and the feeding path for the recording material 2 by the two engaging members 41b, 41cof a main-assembly-side guide 41 and the two guiding rails 40a, 40b. The first guiding rail 40awith which the second engaging member 41bis engaged is linear, and is inclined in a direction crossing with the mounting direction X of the cartridge B from above the positioning guide 44. The second guiding rail 40bwith which the first engaging member 41cis engaged is provided with a first main-assembly-hole portion (first arcuate portion) 40b1 projected outwardly and arcuately about the rotation shaft 15a,which is a center of rotation of the opening and closing member 15. The rail 40bhas a second main-assembly-hole portion (second arcuate portion) 40b2 having a center (unshown) adjacent a positioning guide 44 side end of the first guiding rail 40ahaving a radius equal to a gap between the two engaging members 41b, 41cof the main-assembly-side guide 41, continuing with the first main-assembly-hole portion 40b1.

[0071] Adjacent the opposite longitudinal (longitudinal direction of the cartridge B) ends of a member 15, there are provided first and second plates 15b(sector plates) in the form of a plate having a rotation shaft 15afor the member 15. The sector plate 15bis provided with a cam groove 15cwhich has a first plate-hole portion (arcuate groove) 15c1 extending circularly about a center of rotation (rotation shaft 15a), and a second plate-hole portion (linear groove) 15c2, which is formed continuing from a closing-direction-side end of the first plate-hole portion 15c1 and inclined in the closing direction from the radial direction of the first plate-hole portion 15c1. The first plate-hole portion 15c1 has a radius which is smaller than that of the first main-assembly-hole portion 40b1, and the distance between the front end of the second plate-hole portion 15c2 and the rotation shaft 15ais substantially equal to the radius of the first main-assembly-hole portion 40b1.

[0072] The opening and closing member 15 and the main-assembly-side guide 41 are assembled into the fixed member 40 of the main assembly.

[0073] The opening and closing member 15 is rotatably supported on the main assembly 14 of the apparatus by elastically deforming the sector plate 15bin the longitudinal direction of the cartridge B and engaging the rotation shaft 15ainto the engaging hole 40c(FIG. 5) of the fixed member 40 of the main assembly. The member 15 is rotated in the direction of the arrow Q shown in FIG. 1 about the rotation shaft 15ato open and close the opening W.

[0074] The main-assembly-side guide 41 is mounted in the following manner. The projection 41eat the front end of the second engaging member 41bis aligned (longitudinal direction) with and inserted into the groove of the first guiding rail 40a, and then is rotated. By doing so, the projection 41eis engaged with the back side of the main-assembly fixed member 40, so that it functions as a retainer. Then, the first engaging member 41cpenetrates through the second guiding rail 40b, and is engaged with the cam groove 15cof the member 15. By doing so, the snap fitting claw 41cprovided at the front end of the first engaging member 41cis locked at the back side of the sector plate 15b.

[0075] On the other hand, a side surface (left and right) of a cartridge frame CF of the cartridge B is provided with first and second cartridge guides 18bto be engaged with the guide grooves 41a,the first and second main-assembly-side guides 41, and first and second positioning portions 18a, disposed on an extension line of the rotation shaft of the photosensitive drum 7, for engagement with the first and positioning portions 44a.

[0076] In the first and second cartridge guides 18b, designated by d are first and second portions to be supported (supported portion), and designated by e are first and second urged portions. They correspond to first and second supported portions a and first and second urging portions b, respectively.

[0077] Referring to FIGS. 8 to 14, a description will be provided as to the mounting-and-demounting operation of the cartridge B relative to the mounting-and-demounting mechanism for the cartridge.

[0078] When the opening and closing member 15 of the main assembly 14 of the apparatus is opened completely (full-open state), the front guide 42 and the main assembly side guide 41, which are continued, are exposed, as shown in FIG. 8. Here, the guide groove 42aof the front guide 42 and the guide groove 41aof the main-assembly-side guide 41 are continuous. With this continuing state, the operator inserts the cartridge B so that cartridge guide 18bis guided along the guide groove 42a, 41ain this order. And, it is inserted until the guide 18babuts the trailing edge of the guide groove 41a. The main-assembly-side guide 41 is inclined downward in the mounting direction. Therefore, the weight of the cartridge B is effective to move the cartridge in the inserting direction.

[0079] In other words, the process cartridge is inserted until the abutting portion f of the guide 18babuts the guide regulating portion c of the main-assembly-side guide 41. Then, the projection 18b1 of the guide 18b(FIG. 8) is engaged with the recess 41a1 of the guide groove 41a, so that supported portion d of the guide 18bis received by the supporting portion a of the main-assembly-side guide 41. The urged portion e of the guide 18bis disposed corresponding to the urging portion b of the main-assembly-side guide 41, by which the cartridge B is disposed stationarily relative to the main assembly side guide 41.

[0080] Thus, the cartridge B is mounted to the main-assembly-side guide 41 when the guide groove 41ais continuous with the guide groove 42aof the front guide 42 (first position). Here, the main assembly side guide 41 is inclined downward in the mounting direction X of the cartridge B into the guide groove 41aso that it crosses the feeding direction of the recording material 2 by the feeding means 3 (first pose) at the position where the guide groove 41ais continuous with the guide groove 42a.

[0081] This is accomplished by positioning the first engaging member 41cat the front end portion or leading end portion of the second plate hole portion 15c2, and positioning the second engaging member 41bat the lower end of the first guiding rail 40a(the opening side W end) when the member 15 is in the full-open position. As shown in FIG. 8, the height h of the guide 18bfrom the bottom surface (lower surface) of the cartridge B is substantially equal to the interval 1 between the inclined surface 43aof the front plate 43 and the guide groove 41a. Therefore, when the bottom surface of the cartridge B is placed on the inclined surface 43aof the plate 43, the cartridge guide 18bis spontaneously guided by the guide groove 41aof the main assembly side guide 41.

[0082] In addition, the guide grooves 41a, 42aare inclined downward toward the front. Therefore, when the cartridge guides 18bare guided by the guide grooves 41a, 42a, the cartridge B is led toward the rear of the main-assembly-side guide 41 by the weight of the cartridge B.

[0083] A description will be provided as to the inclination of the guide grooves 41a, 42a. If the inclination of the guide grooves 41a, 42ais too small, the cartridge B is not led toward the rear side of the main-assembly-side guide 41. If it is too large, on the contrary, the impact is significant when the operator releases the cartridge B halfway through insertion along the main-assembly-side guide 41. In view of these factors, the inclination angle is preferably 10°−70° from the horizontal direction. In this embodiment, the inclination angle of the guide grooves 41a, 42ais approximately 40° from the horizontal direction.

[0084] The main-assembly-side guide 41 in this embodiment is moved in interrelation with the opening and closing operation of the cover member 15. Therefore, if the main-assembly-side guide 41 is pushed by the cartridge B, the main-assembly-side guide 41 moves. Therefore, the height of the bottom surface of the cartridge B to the guide 18bchanges relative to the distance between the guide groove 41aand the inclined surface 43aof the plate 43. This causes operability to deteriorate. In addition, if the main-assembly-side guide 41 is moved through a large distance, the guide 18bof the cartridge B passes beyond the lower surface of the main-assembly-side guide 41 with the result that cartridge B would fall into the main assembly 14 of the apparatus. For this reason, in this embodiment, there is provided a front guide 42 which is continuous with the guide groove 41aof the main-assembly-side guide 41 and which is fixed to the main-assembly fixed member 40 at a position upstream of the main-assembly-side guide 41 in the mounting direction X of the cartridge. By the provision of the front guide 42, the problem is solved, and the guide 18bis guided into the guide groove 41aof the main-assembly-side guide 41 with certainty. The front guide 42 is not inevitable although it is effective to improve operability.

[0085] Referring to FIGS. 8 to 12, a description will be provided as to the movement of the cartridge B whose guide 18bis supported by the main-assembly-side guide 41 in accordance with the process of the closing action of the opening and closing member 15.

[0086] When the member 15 is closed by rotation about the rotation shaft 15a, the first engaging member 41cis moved along the first main-assembly-hole portion 40b1 at the front end side of the second plate-hole portion 15c2. As described in the foregoing, the first main-assembly-hole portion 40b1 has its center at the rotation shaft 15aof the member 15 and has a radius which is equal to the distance to the front end of the second plate-hole portion 15c2 of the cam groove 15c. Accordingly, the first engaging member 41bis also moved toward the rear side in the mounting direction X of the cartridge B along the first guiding rail 40a. At this time, the main-assembly-side guide 41 moves toward the rear side while rotating in the clockwise direction, by which the pose of the cartridge B is changed toward that for the image forming operation.

[0087] With the further closing action of the member 15, the cartridge B approaches the horizontal pose, while approaching the image-forming-operation position at the rear side of the main assembly 14 of the apparatus. Then, the outer periphery of the positioning portion 18aof the cartridge B is brought into abutment to the main-assembly-side-regulating portion (projection) 44bprovided at a position upstream of the positioning portion 44aof the main assembly in the movement locus of the cartridge B to the image-forming-operation position (FIG. 10).

[0088] When the member 15 is further closed, the main-assembly-side guide 41 further approaches the image-forming-operation position, and the recess 41a1 of the guide groove 41apushes the projection 18b1 of the guide 18b. That is, the urging portion b at the main-assembly-side guide 41 side presses against the urged portion e at the cartridge guide. 18bside so that the positioning portion 18arides over the main-assembly-side-regulating portion 44bof the positioning guide 44. The positioning portion 18afalls by the weight of the process cartridge B through the difference between the apex 44b1 of the main-assembly-side-regulating portion 44band the positioning portion 44aof the main assembly after the positioning portion 18ais beyond the main-assembly-side regulating portion 44b.

[0089] Then, the cartridge B, which has been supported by the guide 18bin the guide groove 41a, is now supported by the positioning portion 18aprovided on the axis of the rotation shaft of the photosensitive drum 7 by the positioning portion 44aof the main assembly. As described in the foregoing, by supporting the positioning portion 18aprovided on the axis of the photosensitive drum 7 by the positioning portion 44ain the main assembly fixed to the main-assembly fixed member 40 of the main assembly 14, the cartridge B is correctly positioned in the main assembly 14. Therefore, the process cartridge is correctly positioned with proper alignment with the optical system 1, the transfer roller 4, and so on, which require correct positioning relative to the photosensitive drum 7 in the process cartridge.

[0090] A description will be provided as to the movements of the main-assembly-side guide 41 and the opening and closing member 15. As shown in FIG. 10, when the positioning portion 18aof the cartridge B rides over the main-assembly-side regulating portion 44b, the pressing of the cartridge B by the recess 41b1 of the main assembly side guide 41 is completed substantially. At this time, the first engaging member 41cis exposed at the contact (intersection) between the first main-assembly-hole portion 40b1 and the second main-assembly-hole portion 40b2. The second engaging member 41bis disposed at an upper end of the first guiding rail 40a(rear side end of the process cartridge B in the mounting direction). By doing so, the main-assembly-side guide 41 takes such a position that guide groove 41ais substantially parallel with the feeding direction of the recording material 2 by the feeding means 3 at the image-forming-operation position of the cartridge B. That is, the main-assembly-side guide 41 is different from the pose of the first position, at the second position.

[0091] By this, the member 15 is further closed. Then, as shown in FIG. 11, the inclination of the second plate-hole portion 15c2 moves the first engaging member 41cto the second main-assembly-hole portion 40b2. As described in the foregoing, the second main-assembly-hole portion 40b2 has its center on the first guiding rail 40a, and has a radius that is equal to the interval between the first and second engaging members 41c, 41bof the main-assembly-side guide 41. And therefore, when the first engaging member 41cof the main-assembly-side guide 41 is abutted to the lower end of the second main-assembly-hole portion 40b2, the movement of the main-assembly-side guide 41 stops.

[0092] Up to this point, the cover member 15 has rotated through only one of the total rotatable angle. The amount of the rotation of the member 15 is limited for the following reason. For example, when the cartridge B is pressed into the image-forming-operation position by moving the main-assembly-side guide 41 by closing the member 15 to its full-close position, the operator, as shown in FIG. 8, pushes the cartridge B in the moving direction of the main-assembly-side guide 41 after the cartridge B is inserted. Then, the member 15 is likely to start to close.

[0093] In order to avoid this, in this embodiment, the cartridge B is moved by approximately ½ rotation of the total rotatable angle of the cover member 15. Then, even with the operator presses the cartridge B toward the reuse side, there still remains a sufficient gap between the member 15 and the outer casing portion of the main assembly 14 of the apparatus to which the member 15 is contacted in its full-close position.

[0094] The resistance applied when the positioning portion 18aof the cartridge B rides over the main-assembly-side-regulating portion 44b, gives to the operator the feeling of a click, which is indicative of mounting of the cartridge B in place (image forming operation position) in the process of the closing operation of the member 15. By doing so, the operator can be notified of the event of the mounting of the cartridge B at the correct position.

[0095] As described in the foregoing, when the movement of the main-assembly-side guide 41 is completed, the first engaging member 41cis moved into the first plate-hole portion 15c1 (FIG. 12). The first plate-hole portion 15c1, as described in the foregoing, is arcuate about the rotation shaft 15aof the member 15, and the width (the inner diameter along the short side) is slightly larger than the outer diameter of the first engaging member 41c. Therefore, when the member 15 is further closed after the completion of the movement of the main-assembly-side guide 41, the first engaging member 41cmoves along the first plate-hole portion 15c1. By doing so, the member 15 continues to rotate without contacting the main-assembly-side guide 41 or to the cartridge B, and as shown in FIG. 12, it completely closes the opening W (full-close position).

[0096] When the member 15 is completely closed in this manner, image-formation instructions are produced in a controller (unshown) of the main assembly 14 of the apparatus. Then, the main motor (unshown) is driven, and the photosensitive drum 7 is driven through drive transmitting means (unshown). Then, a rotation stopper 20 provided at the front end of the cartridge B abuts the supporting portion 19 for the rotation stopper provided in the main assembly 14 of the apparatus (FIG. 1). In this case, the cartridge B is positioned in the main assembly 14 of apparatus by the rotation stopper 20 and the positioning portion 18asupported by the positioning portion 44aof the main assembly. The guide 18bis provided such that it floats in the guide groove 14aof the main-assembly-side guide 41. That is, the guide 18bis out of contact with the walls constituting the guide groove 14a.

[0097] FIG. 13 and FIG. 14 show the state in which the right and left side cartridge guides 18bof the cartridge B are floating from the main-assembly-side guide 41 (separated state) when the cartridge B is mounted to the main assembly 14 of the apparatus.

[0098] The reason why the positioning portions 18aof the cartridge B are supported by the positioning portions 44a, is that cartridge B is desirably positioned in the main assembly 14 of the apparatus with high precision in order to provide high-quality and high precision images. The position of the main-assembly-side guide 41 in the main assembly 14 of the apparatus is not assured, and therefore, it is not desirable to use the main-assembly-side guide 41 to correctly position the cartridge B.

[0099] A description will be provided as to removal of the cartridge B from the main-assembly-side guide 41 by opening the member 15. The operations are opposite from the foregoing operation.

[0100] When the opening and closing member 15 is opened from the closed position shown in FIG. 12, the first engaging member 41ctravels in the first plate-hole portion 15c1. With this, in the first half of the opening action of the member 15, what happens is only an opening operation of the member 15. With further opening of the member 15, the engaging member 41cis lifted toward the first main-assembly-hole portion 40b1 by the second plate-hole portion 15c2 and the second main-assembly-hole portion 40b2 in the order of FIG. 11 and FIG. 10. By this time, the cartridge guide 18babuts the guide groove 41a, by which the positioning portion 18astarts to separate from the positioning portion 44a. With further opening of the member 15, the first engaging member 41cis moved toward the opening W for the mounting-and-demounting of the cartridge by the front end of the first plate-hole portion 15c1 and the first main-assembly-hole portion 40b1. With this, the second engaging member 41bmoves in the first guiding rail 40ato the position where the operator can grasp the cartridge B. As shown in FIG. 8, when the member 15 is completely open, the guide groove 41abecomes continuous with the guide groove 42a(first position). Then, the cartridge B can be taken out by the operator from the opening W.

[0101] At this time, the first engaging member 41cis placed at the front end of the first plate-hole portion 15c1, so that member 15 is prevented from opening further.

[0102] In the process cartridge mounting-and-demounting mechanism in this embodiment, the first and second engaging members 41c, 41bare moved on the guiding rails 40a, 40bby the closing operation of the member 15 from the full-open position. In the first half of the closing operation of the member 15, the cartridge B is moved from the first position where the cartridge B is mountable to the second position where the cartridge B can be subjected to the image forming operation. In the latter half of the closing operation of the member 15, the engaging member 41bof the main assembly side guide 41 is slid in the cam groove 15cto permit a closing operation to the full-close position of the opening and closing member 15. By the opening operation of the member 15 from the full-close position, the one engaging member 41bof the main assembly side guide 41 is slid in the cam groove 15cof the member 15, by which the member 15 can be opened to the half of the opening stroke. The two engaging members 41b, 41cof the main-assembly-side guide 41 are slid on the guiding rails 40a, 40bin the latter half of the opening operation of the member 15, and the main-assembly-side guide 41 is moved from the second position to the first position.

[0103] By doing so, the cartridge B can be moved in interrelation with the opening and closing operation of the opening and closing member 15. Therefore, even if the cartridge B is to be placed deep in the main assembly 14 of the apparatus, the mounting-and-demounting operation of the cartridge B is easy. The movement of the cartridge B can be carried out in the first half of the opening operation of the member 15 and in the latter half of the closing operation, and the mounting-and-demounting of the cartridge B can be carried out in the first half of the closing operation of the member 15 and in the latter half of the opening operation. Therefore, even if the cartridge B is to be disposed deep into the main assembly 14 of apparatus, there is no need to provide the main assembly 14 of the apparatus with a space for permitting the operator's hand to enter easily when the cartridge B is mounted or demounted. Therefore, usability can be maintained and improved without increasing the size of the main assembly 14 of the apparatus. In addition, since that cartridge B can be placed deep in the main assembly 14, the latitude of the unit disposition in the electrophotographic image forming apparatus A is improved.

[0104] Furthermore, the main-assembly-side guide 41 is moved between the optical system 1 and the feeding means 3, and it takes a pose in which it is inclined downward (crossing with the feeding direction of the recording material 2 by the feeding means 3) in the mounting direction X of the cartridge B to the guide groove 41a(first pose), at the first position, and takes a pose which is different from the pose of the first position.

[0105] Therefore, the cartridge B can be moved between the optical system 1 and the feeding means 3. When the cartridge B is mounted to the main-assembly-side guide 41 placed at the first position, the cartridge B is brought into abutment to the rear side of the guide groove 41aby the weight due to the downward inclination of the main-assembly-side guide 41. While the main-assembly-side guide 41 is moving to the second position, the process cartridge B is at rest at the position.

[0106] When the main-assembly-side guide 41 is at the first position and during movement of the main-assembly-side guide 41 from the first position to the second position, the guide 18bof the cartridge B is retained by the guide groove 41a. When the main-assembly-side guide 41 reaches the second position, the cartridge B is positioned correctly and supported by the positioning portion 44aof the main assembly at the operation-forming-operation position by the positioning portion 18a. Therefore, the cartridge B can be placed at the predetermined position with precision, for the image forming operation.

[0107] The sector plate 15bhaving the cam groove 15cfor moving the main-assembly-side guide 41 is integral with the member 15. Accordingly, the increase in the number of parts required by the cartridge mounting-and-demounting mechanism can be suppressed, thus suppressing the increase of the number of assembling steps, by which the cost increase is minimized.

[0108] The cartridge B is provided with the cartridge guide 18bsupported by the main-assembly-side guide 41 and the positioning portion 18asupported by the positioning portion 44aof the main assembly, which are separate from each other. By this, the first and second main-assembly-side guides 41 (left and right) and the positioning portions 44acan be disposed at the same position in the longitudinal direction of the cartridge B. Therefore, it is not necessary to increase the length of the cartridge B.

[0109] The positioning guide 44 is provided with the positioning portion 44aengageable with the positioning portion 18aof the cartridge B and the main-assembly-side regulating portion 44b,which is disposed upstream of the positioning portion 44awith respect to the moving direction of the main-assembly-side guide 41 from the first position toward the second position and across the movement locus of the positioning portion 18ato the positioning portion 44. Therefore, the positioning portion 18awhich has been moved by the movement of the main-assembly-side guide 41 from the first position to the second position, abuts the main-assembly-side-regulating portion 44b, and rides over the main-assembly-side-regulating portion 44bto guide the positioning portion 18ato the positioning portion 44a. At this position, the process cartridge B can be handed from the main-assembly-side guide 41 to the positioning portion 44aof the positioning guide 44 in the main assembly.

[0110] The front guide 42 is disposed upstream of the main-assembly-side guide 41 in the mounting direction X, and therefore, the main-assembly-side guide 41 placed at the first position can be prevented from being moved by the cartridge B.

[0111] In the foregoing first embodiment, the mounting-and-demounting mechanism has a sector plate 15bintegrally mounted to the opening and closing member 15, the sector plate 15bbeing provided with a cam groove 15cfor guiding the main-assembly-side guide 41. A description will be provided as to a cartridge mounting-and-demounting mechanism in which a cam plate 50 having a cam groove 50afor guiding the main-assembly-side guide 41 and the opening and closing member 15 are provided separately, so that latitude in the design is improved. The same reference numerals that are assigned to the elements of this embodiment hav the corresponding functions in the foregoing embodiment.

[0112] FIG. 15 is an exploded perspective view of the cartridge mounting-and-demounting mechanism in this embodiment. The cam plate 50 is provided with a cam groove 50aincluding an arcuate groove hole 50a1 as a first plate-hole portion similar to the first embodiment and a line groove 50a2 as a second plate-hole portion, a rotation shaft 50bwhich is rotatably engageable with the engaging hole 40cof the main-assembly fixed member 40 and which functions as a center of rotation of the cam plate 50, and a connecting hole 50cin the axis direction of the rotation shaft 50b. The opening and closing member 15 is:provided with a supporting hole 15efor rotatable engagement with a rotation shaft (unshown) at a position away from the engaging hole 40cof the main-assembly fixed member 40, and is provided with a connecting hole 15din the inner surface extending in the longitudinal direction of the cartridge B. The supporting hole 15eand the connecting hole 15dhave axes extending in the axis direction of the rotation shaft 50b. A cam plate 50 is connected to the member 15 through a connection plate 51 (connecting member). The connection plate 51 is disposed in the main-assembly fixed member 40 at a position opposite from the guiding rails 40a, 40b. At the opposite ends thereof, connecting shafts 51a, 51bare provided. A connecting shaft 51aat one end is rotatably engaged in the connecting hole 15dof the member 15. The connecting shaft 51bat the other end is rotatably engaged in the connecting hole 50cof the cam plate 50.

[0113] The cartridge mounting-and-demounting mechanism of this embodiment constitutes a slider crank mechanism by the main-assembly-side guide 41 and the cam plate 50, and constitutes a quadric crank mechanism by the cam plate 50, the member 15, the connection plate 51, and the main assembly 14 of the apparatus. Therefore, the cam plate 50 receives the opening and closing actions of the member 15 through the connection plate 51, and rotates in interrelation with the opening and closing operation of the member 15 about the rotation shaft 50b. By the rotating operation of the cam plate 50 interrelated with the opening and closing operation of the member 15, the main-assembly-side guide 41 moves in the same manner as the first embodiment.

[0114] In the cartridge mounting-and-demounting mechanism of this embodiment, the two engaging members 41b, 41care slid on the guiding rails 40a, 40bby the closing operation of the member 15 from the full-open position. In the first half of the closing operation of the member 15, the cartridge B is moved from the first position where the cartridge B is mountable to the second position where the cartridge B can be subjected to the image forming operation. In the latter half of the closing operation of the member 15, one engaging member 41bis slid in the cam groove 50ato permit the closing action to the full-close position of the member 15. By the opening operation of the member 15 from the full-close position, one engaging member 41bis slid in the cam groove 50ato permit the opening operation of the member 15 to the first half of the opening operation. In the latter half of the opening operation of the member 15, two engaging members 41b, 41care slid on the guiding rails 40a, 40bto move the main-assembly-side guide 41 from the second position to the first position.

[0115] In this embodiment, the same advantageous effects as the first embodiment can be provided. When the outer casing unit having the member 15 is changed to meet particular desires in the world for example, or when the outer casing is changed by a model change, and the center of rotation position of the member 15 is changed, the cartridge mounting-and-demounting mechanism in the main assembly 14 of the apparatus can be used as it is if the inter-axis distance of the connection plate 51 and the position of the connecting hole 15dof the member 15 is changed.

[0116] In the first and second embodiments, a cartridge mounting-and-demounting mechanism is provided in which the member 15 or the cam plate 50 constitutes a crank, and a slider crank mechanism with the main assembly side guide 41 is the slider. In the first and second embodiments, the main-assembly-side guide 41 is directly moved by the rotation of the member 15 or the cam plate 50 as the crank. Therefore, the loss of the force is small, and the structure is stable.

[0117] The cartridge mounting-and-demounting mechanism of this embodiment is advantageous in the latitude of the movement locus of the main-assembly-side guide 41 and the movement locus of the cartridge B, which is moved by the main-assembly-side guide 41.

[0118] The same reference numerals as the first embodiment are assigned to the element having the corresponding functions as with the first embodiment.

[0119] FIG. 16 is an exploded perspective view of a cartridge mounting-and-demounting mechanism according to this embodiment. In FIG. 16, the opening and closing member 15 has a sector plate 15bprovided with a cam groove 15cwhich includes a first plate-hole portion 15c1 extending about the rotation shaft 15asimilarly to the first embodiment and a second plate-hole portion 15c2, which is continuous from the first plate-hole portion 15c1 and which is inclined downward toward the closing direction relative to the radial direction of the member 15. The member 15 is provided with a supporting hole 15efor supporting it rotatably on the rotation shaft 15a(FIG. 17), at the front end adjacent the center of the sector-shape of the sector plate 15b. The main-assembly-side guide 41 has the same shape as the first and second embodiments.

[0120] It is provided with a guide groove 41ain which the guide 18bof the cartridge B is guided in the opening W side surface. The side opposite from the guide groove 41ais provided with first and second engaging members 41c, 41b. An inner plate 62 of the main assembly 14 of the apparatus is provided with first and second guiding rails 40c, 40das holding means for determining a movement locus of the main-assembly-side guide 41 by engagement with the engaging members 41b, 41cof the main-assembly-side guide 41. The guiding rails 40c, 40dcan be designed such that the cartridge B guided by the main-assembly-side guide 41 can avoid the inner parts in the main assembly 14 of the apparatus.

[0121] At the side of the inner plate 62 opposite from the guiding rails 40c, 40d, there is provided a connection cam plate 60 as a cam member connecting the first engaging member 41cand the cam groove 15cof the member 15. A cam shaft 61, which is a shaft for holding the pose of the connection cam plate 60, is fixed to the inner plate 62. The cam shaft 61 is penetrated through the inner plate 62 and is projected toward the connection cam plate 60. The connection cam plate 60 is provided at one end of the main assembly 60dof the plate with an engaging hole 60afor rotatably supporting a first engaging member 41c, and at the other end with a boss 60bas a projected guide for slidable engagement with the cam groove 15cof the member 15. At the front end of the boss 60b, a snap fitting claw 60b1 is provided for a retainer. The connection cam plate 60 rotatably supports the first engaging member 41cof the main-assembly-side guide 41 in the engaging hole 60a, and the boss 60bis in slidable engagement with the cam groove 15cof the member 15.

[0122] A cam groove 60cis formed between the engaging hole 60aand the boss 60bin the main assembly 60dof the plate of the connection cam plate 60. The cam groove 60cis slidably engaged with the cam shaft 61 fixed to the inner plate 62.

[0123] Referring to FIGS. 17 to 21, a description will be provided as to the opening and closing operation of the member 15 and the movement of the main-assembly-side guide 41 in the cartridge mounting-and-demounting mechanism of this embodiment. The same thing as with the first embodiment applies to this embodiment as to the mounting of the cartridge B to the main-assembly-side guide 41, the engagement between the positioning portion 44aof the main assembly and the positioning boss 18bof the cartridge B, and the subsequent figure supporting of the cartridge B in the main assembly 14 of the apparatus. Therefore, a description thereof is omitted for simplicity.

[0124] FIG. 17 shows the state in which the member 15 is completely open (full-open position). Similarly to first embodiment, the cartridge B is inserted into the opening W. At this time, the first engaging member 41cabuts to the member 15 side end of the second guiding rail 40d. Between the second engaging member 41band opening and closing member side end of the first guiding rail 40c, a small clearance remains. In this case, one end side of the cam plate 60 is supported by the first engaging member 41cand the engaging hole 60a. At the other end side of the connection cam plate 60, the boss 60babuts to the front end of the first plate-hole portion 15c1.

[0125] When the member 15 is closed, as shown in FIGS. 18 and 19, the cam plate 60 is moved toward the rear side of the main assembly 14 of the apparatus while keeping the abutment between the boss 60band the end of the second plate-hole portion 15c2. The portion of the cam groove 60cfrom one end 60c1 to a bent portion 60c2 corresponds to the track of the cam shaft 61 of the inner plate 62 during the movement of the connection cam plate 60 with the connecting relation maintained.

[0126] When the member 15 is further closed from the position shown in FIG. 19 to the position shown in FIG. 20, the movement of the main-assembly-side guide 41 approaches the final stage. At this time, the abutment between the cam groove 60cand the cam shaft 61 of the inner plate 62 changes from the bent portion 60c2 to the other end 60c3 of the cam groove 60c. When the cam shaft 61 moves between the bent portion 60c2 and the other end 60c3, the connection cam plate 60 rotates above the engaging hole 60arelative to the first engaging member 41c. The boss 60bprovided at the other end side of the connection cam plate 60 is moved from the front end of the second plate-hole portion 15c2 to the connection side (intersection side) between the second plate hole portion 15c2 and the arcuate groove hole 15c1. As shown in FIG. 20, when the boss 60bis moved to the arcuate hole 15c1, the main-assembly-side guide 41 completes its motion on the guiding rails 40c, 40d. By this, the cartridge B becomes supported by the positioning guide 44. At this time, the opening and closing member 15 is at ½ the full stroke of the closing operation similarly to the first and second embodiments. When the member 15 is further closed, the boss 60bslides in the first plate-hole portion 15c1. Therefore, the member 15 can be completely closed to the full-close position as shown in FIG. 21 without an external force imparted to the connection cam plate 60.

[0127] A description will be provided as to a pulling operation to move the cartridge B to the position where the cartridge B can be easily taken out from the closed position of the member 15.

[0128] The operations are opposite from the process described in the foregoing. When the member 15 is between the closed position (FIG. 21) and the position shown in FIG. 20, the connection cam plate 60, the main-assembly-side guide 41, and the cartridge B are not moved, and only the member 15 is opened. This is because the first plate-hole portion 15c1 is circular about the center of rotation of the member 15 with the radius equal to the distance of a line connecting the boss 60band the rotation shaft 15aof the member 15. Until the position shown in FIG. 20, with the opening of the member 15, the boss 60bcontacts the first plate-hole portion 15c1 and then to the second plate-hole portion 15c2, and starts movement of the main-assembly-side guide 41 toward the opening W. Then, the cartridge B carried on the main-assembly-side guide 41 is disengaged from the positioning guide 44 and starts to move with the main-assembly-side guide 41. The abutment between the boss 60band the cam groove 15cchanges toward the front end side of the second plate-hole portion 15c2 (FIG. 20 to FIG. 19). Thereafter, in interrelation with the opening operation of the member 15, the main-assembly-side guide 41 slides on the guiding rails 40c, 40d(FIG. 18 to FIG. 17). As shown in FIG. 17, when the member 15 is completely opened (full-open position), the cartridge B has been pulled out to such a position that an operator can access it. Subsequently, the operator pulls it along the guide groove 41aof the main-assembly-side guide 41, by which the cartridge B is taken out.

[0129] Thus, in the cartridge mounting-and-demounting mechanism of this embodiment, the two engaging members 41b, 41cof the main-assembly-side guide 41 is slid on the two guiding rails 40c, 40dby the closing operation from the full-open position of the member 15. In the first half of the closing operation of the member 15, the cartridge B is moved from the first position where the cartridge B is mountable to the second position where the cartridge B can be subjected to the image forming operation. In the latter part of the closing operation of the member 15, the cam shaft 61 slides in the cam groove 60c, and the boss 60bslides in the cam groove 15cto permit the closing action of the member 15 to the full-close position. By the opening operation of the member 15 from the full-close position, the cam shaft 61 slides in the cam groove 60c, and the boss 60bslides in the cam groove 15cof the member 15 to permit the opening action of the member 15 to the first half of the opening action. In the latter half of the opening operation of the member 15, two engaging members 41b, 41care slid on the guiding rails 40a, 40bto move the main-assembly-side guide 41 from the second position to the first position.

[0130] Thus, in this embodiment, by using the cartridge mounting-and-demounting mechanism, the same advantageous effects as with first embodiment can be provided, and in addition, the movement of the main-assembly-side guide 41 in interrelation with the opening and closing operation of the member 15 is effected through the connection cam plate 60. Therefore, the movement locus of the main-assembly-side guide 41 and the movement locus of the cartridge B moved by the main-assembly-side guide 41 are not limited, so that the latitude in the design can be improved.

[0131] The above-described embodiments can be summarized as follows.

[0132] First, the mounting mechanism for the process cartridge is summarized.

[0133] There is provided a process-cartridge mounting mechanism for mounting a process cartridge (B) to a mounting position in a main assembly (14) of an electrophotographic image forming apparatus, wherein the cartridge (B) comprises an electrophotographic photosensitive member (7) and process means (at least one of 8, 10 and 11) actable on the photosensitive member (7), the process-cartridge mounting mechanism comprising an openable cover member (15) mounted to the main assembly (14) of the apparatus, the cover member (15) being opened and closed when the cartridge (B) is mounted to or demounted from the main assembly (14) of the apparatus; a first main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), the first main-assembly-side guide (41) including a first supporting portion (a) and a first urging portion (b); a second main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), the second main-assembly-side guide (41) including a second supporting portion (a) and a second urging portion (b); a first cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position; the first cartridge guide (18b) including a first supported portion (d) to be supported on the first supporting portion (a) and a first urged portion (e) to be urged to the first urging portion (b); a second cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position, the second cartridge guide (18b) including a second supported portion (d) to be supported on the second supporting portion (a) and a second urged portion (e) to be urged to the second urging portion (b); wherein the cartridge (B) is mounted to the mounting position in interrelation with a closing operation of the cover member (15).

[0134] As regards the electrophotographic image forming apparatus, there is provided an electrophotographic image forming apparatus for forming an image of a recording material, to which a process cartridge (B) is detachably mountable, the apparatus comprising (a) an openable cover member (15) mounted to the main assembly of the apparatus, the cover member (15) being opened and closed when the cartridge (B) is mounted to or demounted from the main assembly of the apparatus; (b) a first main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), the first main-assembly-side guide (41) including a first supporting portion (a) and a first urging portion (b); (c) a second main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), the second main-assembly-side guide (41) including a second supporting portion (a) and a second urging portion (b); (d) mounting means for mounting a process cartridge (B), the process cartridge (B) including: process means (at least one of 8, 10 and 11) actable on the electrophotographic photosensitive member (7); a first cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position, the first cartridge guide (18b) including a first supported portion (d) to be supported on the first supporting portion (a) and a first urged portion (e) to be urged to the first urging portion (b); a second cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position, the second cartridge guide (18b) including a second supported portion (d) to be supported on the second supporting portion (a) and a second urged portion (e) to be urged to the second urging portion (b); wherein the cartridge (B) is mounted to the mounting position in interrelation with a closing operation of the cover member (15).

[0135] As regards the process cartridge, there is provided a process cartridge (B) detachably mountable to a main assembly of an electrophotographic image forming apparatus for forming an image on a recording material, wherein the image forming apparatus includes an openable cover member (15) mounted to the main assembly of the apparatus, the cover member (15) being opened and closed when the cartridge (B) is mounted to or demounted from the main assembly of the apparatus; a first main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), the first main-assembly-side guide (41) including a first supporting portion (a) and a first urging portion (b); and a second main-assembly-side guide (41) which is provided in the main assembly of the apparatus and which is movable in interrelation with an opening and closing operation of the cover member (15), said second main-assembly-side guide (41) including a second supporting portion (a) and a second urging portion (b); an electrophotographic photosensitive member (7); process means (at least one of 8, 10 and 11) actable on the photosensitive member (7); a cartridge frame (CF); a first cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position, the first cartridge guide (18b) including a first supported portion (d) to be supported on the first supporting portion (a) and a first urged portion (e) to be urged to the first urging portion (b); a second cartridge guide (18b), provided in the cartridge (B) at one longitudinal end of a cartridge frame (CF), for guiding the cartridge (B) toward the mounting position, the second cartridge guide (18b) including a second supported portion (d) to be supported on the second supporting portion (a) and a second urged portion (e) to be urged to the second urging portion (b); wherein the cartridge (B) is mounted to the mounting position in interrelation with a closing operation of the cover member (15).

[0136] By moving the second cartridge guide 18band by urging the first urged portion e with the first urging portion b, and by urging the second urged portion e with the second urging portion b, the cartridge B is mounted to the mounting position in interrelation with the closing operation of the member 15.

[0137] According to another aspect, the first cartridge guide (18b) includes an abutting portion (f) for abutting a guide regulating portion (c) provided in the first supporting portion (a), the abutting portion (f) being provided at a front end of the first cartridge guide (18b) in a mounting direction of the cartridge (B); and the first cartridge guide (18b) includes an abutting portion (f) abutting a guide regulating portion (c) provided in the first supporting portion (a), the abutting portion (f) being provided at a front end of the first cartridge guide (18b) in a mounting direction of the cartridge (B).

[0138] According to a further aspect, the invention relates to a process cartridge mounting mechanism according to the cartridge noted above, wherein the first urged portion (e) and the first supported portion (d) are integrally molded, and the second urged portion (e) and the second supported portion (d) are integrally molded.

[0139] According to a further aspect, the first cartridge guide (18b) is projected outwardly from a cartridge frame (CF) portion provided at one longitudinal end of the cartridge frame (CF), and the first cartridge guide (18b) is integrally molded with the cartridge frame (CF); and the second cartridge guide (18b) is projected outwardly from a cartridge frame (CF) portion provided at the other longitudinal end of the cartridge frame (CF), and the second cartridge guide (18b) is integrally molded with the cartridge frame (CF).

[0140] According to a further aspect, one longitudinal end of the cartridge frame (CF) is provided with a first positioning portion (18a) for positioning the cartridge (B) to the mounting position, and the other longitudinal end of the cartridge frame (CF) is provided with a second positioning portion (18a) for positioning the cartridge (B) to the mounting position, wherein the first positioning portion (18a) and the second positioning portion (18a) are engaged with a main-assembly-side-positioning portion (44a, 44a) provided in the main assembly.

[0141] According to a further aspect, the photosensitive member (7) is in the form of a drum, and wherein the first positioning portion (18a) and the second positioning portion (18a) are coaxial with the photosensitive drum.

[0142] According to a further aspect, the first cartridge guide (18b) and the second cartridge guide (18b) are so disposed so that first cartridge guide (18b) is above the first positioning portion (18a) in a vertical direction, and the second cartridge guide (18b) is above the second positioning portion (18a), when the cartridge (B) is mounted to the mounting position.

[0143] According to a further aspect, the first urging portion (b) urges the first urged portion (e), and the second urging portion (b) urges the second urged portion (e), after the cover member (15) is closed to a predetermined angle.

[0144] According to a further aspect, after completion of the movement of the cartridge (B) to the mounting position, the first urging portion (b) and the first urged portion (e) are away from each other, and the second urging portion (b) and the second urged portion (e) are away from each other.

[0145] According to a further aspect, the main assembly of the apparatus is provided with a main-assembly-side regulating portion (44b) for limiting entering of the first positioning portion (18a) and the second positioning portion (18a) to the mounting position, and the first positioning portion (18a) and the second positioning portion (18a) contact the main-assembly-side regulating portion (44b), the first urging portion (b) urges the first urged portion (e), and the second urging portion (b) urges the second urged portion (e) so that first positioning portion (18a) and the second positioning portion (18a) enter the main-assembly-side positioning portion (44a, 44a).

[0146] According to a further aspect, the regulating portion is in the form of a projection (44b) or a spring (45) disposed at an entrance of the main-assembly-side positioning portion (44a, 44a).

[0147] According to a further aspect, mounting of the cartridge (B) to the mounting position is completed prior to completion of closing of the to cover member (15) relative to the main assembly of the apparatus.

[0148] According to a further aspect, mounting of the cartridge (B) to the mounting position is completed in interrelation with a closing operation of the cover member (15) from its full-open position to a predetermined angle, and in a closing operation beyond the predetermined angle, the cartridge (B) is not moved; and in an opening operation of the cover member (15) from a closed position to a predetermined angle, the cartridge (B) is not moved, and in an opening operation beyond the predetermined angle, the cartridge (B) is moved to a taking-out position.

[0149] According to a further aspect, the first main-assembly-side guide (41) and the second main-assembly-side guide (41) are inclined downward substantially toward the mounting position.

[0150] According to a further aspect, the use may be made with a first plate (15b), which is rotatable about a center (15a) of rotation relative to first main-assembly fixed member (40) in interrelation with the opening and closing operation of the cover member (15), a first arcuate slot (15c1) provided in the first plate (15b), the slot being arcuate with a first radius, a second slot (15c2) radially outwardly extended from an end of the first arcuate slot (15c1) in the first plate (15b) toward a second radius, a first arcuate slot (40b1) formed in the main-assembly fixed member, and a second slot (40b2) radially inwardly extended from an end of the first arcuate slot (40b1) of the main-assembly-fixed member toward the first radius, a first engaging member (41c) movable in the first arcuate slot (15c1) of said first plate (15b), a second slot (15c2) of the first plate (15b), a first arcuate slot (40b1) of the main-assembly fixed member, and a second slot (40b2) of the main-assembly fixed member; wherein the first main-assembly-side guide (41) is moved by moving the first engaging member (41c) which is in the second slot (15c2) of the first plate (15b), in said first arcuate slot (15c1) of said first plate (15b) by moving the cover member (15) from its full-open position in a closing direction; and wherein when the first engaging member (41c) reaches the second slot (40b2) of the main assembly, the second slot (15c2) is moved with the first engaging member (41c) being at rest, so that the cover member (15) is closed without movement of the first main-assembly-side guide (41).

[0151] According to a further aspect, the cartridge (B) is moved to a taking-out position in interrelation with an opening operation of the cover member (15) while the first cartridge guide (18b) is supported on the first main-assembly-side guide (41), and the second cartridge guide (18b) is supported on the second main-assembly-side guide (41).

[0152] The operation of the devices according to the foregoing embodiments are as follows. First, the cover member 15 is opened. This moves the second main-assembly-side guide 41 to the cartridge inserting position (cartridge mounting-and-demounting position, or first position). Then, the operator grasps the cartridge B and places the first cartridge guide 18bof the process cartridge on the first main-assembly-side guide 41. The operator also places the second cartridge guide 18bon the second main-assembly-side guide 41. The first and second cartridge guides 18bslide on the first and second main-assembly-side guides 41 toward the rear side by the pushing force of the operator and/or the weight of the cartridge B. The cartridge B stops by abutment of the abutting portion f of the second cartridge guide 18bto the guide regulating portion c. At this time, first urged portion e is opposed to the first urging portion b. Similarly, the second urged portion e is opposed to the second urging portion b. When the cover member 15 closes through a predetermined angle, the positioning portion 18babuts the main-assembly-side regulating portion 45. This applies a movement load to the cartridge B. In interrelation with further closing action of the cover member 15, the first urging portion b pushes the first urged portion e. Similarly, the second urging portion b pushes the second urged portion e. By this, the cartridge B is moved further rearward. The cartridge positioning portion 18ais engaged with the main assembly positioning portion 44a. Thus, the cartridge B is mounted to the mounting position of the main assembly 14 of the apparatus.

[0153] When the cartridge B is to be taken out of the main assembly 14 of the apparatus, the operation is opposite from that described above as follows. In interrelation with the opening operation of the cover member, the first and second main-assembly-side guides 41 are moved to the cartridge insertion position (cartridge mounting-and-demounting position, or the first position). The operator grasps the cartridge B and takes it out of the main assembly 14.

[0154] By this, the cartridge B can be moved to the mounting position from the cartridge insertion position in interrelation with the closing operation of the cover member. In interrelation with the opening operation of the cover member, the cartridge B may be moved from the mounting position to the cartridge insertion position. By the operator inserting the cartridge B at the front side of the main assembly of the apparatus (closer side to the operator), the cartridge is moved toward the rear side from the front side by closing the cover member 15. Additionally, by the operator opening the cover member 15, the cartridge is moved from the rear side to the front side (closer to the operator).

[0155] In the foregoing embodiments, the main-assembly-side regulating portion 44bprovided on the guide 44 enters the movement locus of the positioning portion 18awith respect to the positioning portion 44ain order to engage the positioning portion 18aof the process cartridge B with the main-assembly-positioning portion 44aof the positioning guide 44 provided on the main-assembly fixed member 40, 62. However, in order to more positively engage the positioning portion 18aof the process cartridge B with the main assembly positioning portion 44a, the positioning guide 44 may provided with a twist coil spring 45 (an elastic member having a bent portion 45a(having an “L” shaped bent shape, as shown in FIG. 22)) such that the bent portion 45aenters the movement locus of the positioning portion 18a.

[0156] In such a positioning guide 44, when the positioning portion 18aapproaches the main-assembly-side positioning portion 44aof the positioning guide 44 with the movement of the process cartridge B along the main-assembly-side guide 41 (FIG. 22 (a)), the outer diameter of the positioning portion 18acontacts the bent point of the bent portion 45aof the twist coil spring 45. By the movement of the process cartridge B, the positioning portion 18acauses an elastic deformation of the bent portion 45aof the twist coil spring 45 upwardly, so as to escape from the movement locus of the positioning portion 18a. When the positioning portion 18apasses by the bent point 45bof the twist coil spring 45, the restoring force (elastic force) stored in the twist coil spring 45 by the retraction of the bent portion 45afunctions to press the positioning portion 18ato the positioning portion 44aof the positioning guide 44 (FIG. 22, (c)). The arm portion 45cof the twist coil spring 45 functions to contact the positioning portion 18aclosely to the main assembly positioning portion 44awith a predetermined pressure, so that the positioning boss 2 of the process cartridge B is raised from the positioning guide 44 by the contact force of the transfer roller 4 to the photosensitive drum 7. By using such a positioning guide 44, the positioning portion 18aof the process cartridge B can be more positively fixed to the positioning guide 44.

[0157] The process cartridge in the first embodiment was of a type which formed a monochromatic image. However, the present invention is preferably applicable not only to a process cartridge which forms a monochromatic image, but also to a process cartridge which comprises multiple developing means and forms a multi-color image (for example, a two-color image, a three-color image, or a full-color image).

[0158] Also, the electrophotographic photosensitive member is not limited to the photosensitive drum alone. For example, the following may be included. First, as for the photosensitive material, photoconductive material, amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, or organic photoconductive material, may be included. As for the configuration of the base on which the photosensitive material is coated, a rotary configuration such as a drum shape, or a flat configuration such as a belt shape, may be included.

[0159] Also, the present invention is preferably usable with various known developing methods such as the magnetic brush developing method using two component toner, the cascade developing method, the touch-down developing method, and the cloud developing method.

[0160] However, another method, such as corona charging, is usable, in which a tungsten wire is enclosed by metal shield of aluminum or the like at three sides of the wire, and positive or negative ions are produced by applying a high voltage to the tungsten wire, and the surface of the photosensitive drum is uniformly charged by moving positive or negative ions to the surface.

[0161] The charging means may be of a blade type (charge blade), a pad type, a block type, a rod type, or a wire type, in addition to the aforementioned roller type.

[0162] The means for cleaning the toner remaining on the photosensitive drum may be of a blade type, a fur brush type, a magnetic brush type, or the like.

[0163] The process cartridge contains the electrophotographic photosensitive member and at least one process means. One type of the process cartridge contains the electrophotographic photosensitive member and the charging means as a unit or cartridge, which is detachably mountable to the main assembly of the apparatus. Another type of the process cartridge contains the electrophotographic photosensitive member and the developing means as a unit or a cartridge which is detachably mountable to the main assembly of the apparatus. A further type contains the electrophotographic photosensitive member and the cleaning means as a unit or a cartridge, which is detachably mountable to the main assembly of the apparatus. A further type of the process cartridge contains the electrophotographic photosensitive member and at least two process means as a unit or a cartridge, which is detachably mountable to the main assembly of the apparatus.

[0164] For example, the process cartridge may contain the electrophotographic photosensitive member and the charging means, the developing means or the cleaning means, which are unified into a cartridge which is detachably mountable to the main assembly of the apparatus. Another type contains at least one of the charging means, the developing means and the cleaning means as a unit or a cartridge which is detachably mountable to the main assembly of the image forming apparatus. Furthermore, it may contain at least the developing means and the electrophotographic photosensitive member as a unit or a cartridge, which is detachably mountable to the main assembly of the image forming apparatus. The process cartridge can be mounted to or demounted from the main assembly of the apparatus by the user. This means that that user can carry out the maintenance operation in effect.

[0165] Further, in the preceding embodiments, an electrophotographic image forming apparatus was exemplified by an electrophotographic laser beam printer, but the present invention does not need to be limited to the preceding embodiments. It is obvious that the present invention is also applicable to other electrophotographic image forming apparatuses such as an electrophotographic LED printer, an electrophotographic copying machine, an electrophotographic facsimile apparatus, or an electrophotographic word processor.

[0166] As described in the foregoing, the present invention improves the mounting operability of the process cartridge relative to the main assembly of the electrophotographic image forming apparatus.

[0167] While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purpose of the improvements or the scope of the following claims.