Process cartridge with cleaning frame having reinforcing member

[0002] 1. Field of the Invention

[0003] The present invention relates to a cleaning frame, a process cartridge and an electrophotographic image forming apparatus onto which such a process cartridge is detachably mountable.

[0004] The electrophotographic image forming apparatus serves to form an image on a recording medium by using an electrophotographic image forming process and may be embodied, for example, as an electrophotographic copying machine, an electrophotographic printer (for example, LED printer, laser beam printer or the like), an electrophotographic facsimile apparatus or an electrophotographic word processor.

[0005] On the other hand, the process cartridge may integrally incorporate an electrophotographic photosensitive member and a charging means or a developing means and a cleaning means as a cartridge unit which is detachably mountable to a main body of the electrophotographic image forming apparatus, or may integrally incorporate an electrophotographic photosensitive member and the cleaning means and at least one of the charging means and the developing means as a cartridge unit which is detachably mountable to a main body of the electrophotographic image forming apparatus, or may integrally incorporate an electrophotographic photosensitive member and at least the cleaning means as a cartridge unit which is detachably mountable to a main body of the electrophotographic image forming apparatus.

[0006] 2. Related Background Art

[0007] In the past, since a cleaning frame is disposed in the vicinity of the fixing means by the fact that the cleaning means is followed by the fixing means, due to inherent constructural feature of an image forming apparatus, the cleaning frame might be deformed by heat from the fixing means. Of course, the greater a sheet pass width the greater an amount of thermal deformation.

[0008] Conventionally, in an image forming apparatus using an electrophotographic image forming process, a process cartridge obtained by integrally incorporating an electrophotographic photosensitive member and a process means acting on the electrophotographic photosensitive member as a cartridge unit which is detachably mountable to a main body of the electrophotographic image forming apparatus has been used. By using such a process cartridge, since maintenance of the apparatus can be performed by the operator himself without any expert, operability can be improved remarkably. Thus, the process cartridge has widely been used with the image forming apparatus.

[0009] The process cartridge is constituted by a cleaning unit integrally including a charging means, a cleaning means and a photosensitive drum, and a developing unit integrally including developing means and toner to be supplied to the developing means. The cleaning unit and the developing unit are interconnected by joining members, thereby forming the process cartridge.

[0010] In an image forming apparatus onto which such a process cartridge is detachably mountable, in some cases, in a condition that the process cartridge is mounted, the cleaning unit is opposed to the fixing means.

[0011] An object of the present invention is to provide a cleaning frame which is hard to be thermally deformed in an electrophotographic image forming apparatus in which thermal fixing means is opposed to the cleaning frame for supporting a cleaning means, a process cartridge having such a cleaning frame, and an electrophotographic image forming apparatus onto which such a process cartridge is detachably mountable.

[0012] To achieve the above object, according to an embodiment of the present invention, there is provided a cleaning frame used in a process cartridge which is detachably mountable to a main body of an electrophotographic image forming apparatus and which includes an electrophotographic photosensitive drum, and a cleaning member for removing developer adhered to the electrophotographic photosensitive drum, the cleaning frame comprising a drum attaching portion for attaching the electrophotographic photosensitive drum, a cleaning member attaching portion for attaching the cleaning member, one end wall provided at one longitudinal end of the cleaning frame, the other end wall provided at the other longitudinal end of the cleaning frame, an exposure opening for receiving information light to be illuminated onto the electrophotographic photosensitive drum attached to the drum attaching portion when the process cartridge is mounted to the main body of the apparatus, and a reinforcing member provided between the one end wall and the other end wall along the longitudinal direction of the cleaning frame at a side opposite to a side at which the exposure opening is provided in a direction transverse to the longitudinal direction of the cleaning frame.

[0013] According to another embodiment of the present invention, there is provided a process cartridge which is detachably mountable to a main body of an electrophotographic image forming apparatus, the process cartridge comprising (a) a cleaning frame including a drum attaching portion for attaching an electrophotographic photosensitive drum, a cleaning member attaching portion for attaching a cleaning member, one end wall provided at one longitudinal end of the cleaning frame, the other end wall provided at the other longitudinal end of the cleaning frame, an exposure opening for receiving information light to be illuminated onto the electrophotographic photosensitive drum attached to the drum attaching portion when the process cartridge is mounted to the main body of the apparatus, and a reinforcing member provided between the one end wall and the other end wall along the longitudinal direction of the cleaning frame at a side opposite to a side at which the exposure opening is provided in a direction transverse to the longitudinal direction of the cleaning frame, (b) the electrophotographic photosensitive drum attached to the drum attaching portion, and (c) the cleaning member attached to the cleaning member attaching portion.

[0014] According to a further embodiment of the present invention, there is provided an electrophotographic image forming apparatus onto which a process cartridge is detachably mountable for forming an image on a recording medium, the electrophotographic image forming apparatus comprising (a) a mounting means capable of detachably mounting a process cartridge including a cleaning frame having a drum attaching portion for attaching an electrophotographic photosensitive drum, a cleaning member attaching portion for attaching a cleaning member, one end wall provided at one longitudinal end of the cleaning frame, the other end wall provided at the other longitudinal end of the cleaning frame, an exposure opening for receiving information light to be illuminated onto the electrophotographic photosensitive drum attached to the drum attaching portion when the process cartridge is mounted to the main body of the apparatus, and a reinforcing member provided between the one end wall and the other end wall along the longitudinal direction of the cleaning frame at a side opposite to a side at which the exposure opening is provided in a direction transverse to the longitudinal direction of the cleaning frame; the electrophotographic photosensitive drum attached to the drum attaching portion; and the cleaning member attached to the cleaning member attaching portion, and (b) a conveying means for conveying the recording medium.

[0015] According to a still further embodiment of the present invention, there is provided a cleaning frame of a process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus, which cleaning frame supports an electrophotographic photosensitive drum and a cleaning blade for removing developer as waste toner remaining on the electrophotographic photosensitive drum after transferring and has a waste toner chamber, wherein a rib reaching to both end walls of a body of the cleaning frame with respect to a longitudinal direction of the electrophotographic photosensitive drum substantially in parallel with the electrophotographic photosensitive drum and defining a gap between the rib and a wall of the waste toner chamber opposed to the electrophotographic photosensitive drum is provided in the waste toner chamber.

[0016] According to a further embodiment of the present invention, there is provided a process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus, the process cartridge comprising an electrophotographic photosensitive drum, a cleaning blade for removing developer as waste toner remaining on the electrophotographic photosensitive drum after transferring, and a cleaning frame supporting the electrophotographic photosensitive drum and the cleaning blade and having a waste toner chamber, wherein a rib reaching to both end walls of a body of the cleaning frame with respect to a longitudinal direction of the electrophotographic photosensitive drum substantially in parallel with the electrophotographic photosensitive drum and defining a gap between the rib and a wall of the waste toner chamber opposed to the electrophotographic photosensitive drum is provided in the waste toner chamber.

[0017] According to a still further embodiment of the present invention, there is provided an electrophotographic image forming apparatus onto which a process cartridge is detachably mountable for forming an image on a recording medium, the electrophotographic image forming apparatus comprising (a) a mounting means capable of detachably mounting a process cartridge including an electrophotographic photosensitive drum, a cleaning blade for removing developer as waste toner remaining on the electrophotographic photosensitive drum after transferring, and a cleaning frame supporting the electrophotographic photosensitive drum and the cleaning blade and having a waste toner chamber and wherein a rib reaching to both end walls of a body of the cleaning frame with respect to a longitudinal direction of the electrophotographic photosensitive drum substantially in parallel with the electrophotographic photosensitive drum and defining a gap between the rib and a wall of the waste toner chamber opposed to the electrophotographic photosensitive drum is provided in the waste toner chamber, (b) a thermal fixing means opposed to the cleaning frame at a front side of the process cartridge in a mounting direction at the process cartridge, and (c) a conveying means for conveying the recording medium.

[0018] FIG. 1 is a side sectional view of an electrophotographic image forming apparatus to which an embodiment of the present invention is applied;

[0019] FIG. 2 is a perspective view of the apparatus of FIG. 1;

[0020] FIG. 3 is a side sectional view of a process cartridge to which an embodiment of the present invention is applied;

[0021] FIG. 4 is a schematic perspective view of the process cartridge of FIG. 3;

[0022] FIG. 5 is a perspective view of the process cartridge of FIG. 3, looked at from below;

[0023] FIG. 6 is a side sectional view of a process cartridge to which an embodiment of the present invention is applied;

[0024] FIG. 7 is a vertical sectional view showing a seal arrangement between a cleaning blade and a cleaning frame;

[0025] FIG. 8 is an explanatory view showing a mold for molding a conventional cleaning frame;

[0026] FIG. 9 is an explanatory view showing a mold for molding a conventional cleaning frame;

[0027] FIG. 10 is an explanatory view showing a mold for molding a cleaning frame according to the present invention, in an embodiment of the present invention;

[0028] FIG. 11 is a side view showing a welding positioning portion and a positioning portion of a cleaning frame (with respect to a main body of an image forming apparatus) according to an embodiment of the present invention;

[0029] FIG. 12 is a horizontal sectional view of a cleaning frame according to an embodiment of the present invention;

[0030] FIG. 13 is a vertical sectional view showing a state that waste toner is accumulated in a cleaning frame according to an embodiment of the present invention;

[0031] FIG. 14 is a schematic horizontal sectional view showing a state that a conventional cleaning frame and a cleaning blade are deformed and expanded by hear from a fixing device;

[0032] FIG. 15 is a horizontal sectional view of a cleaning frame according to another embodiment of the present invention; and

[0033] FIG. 16 is a bottom view of a process cartridge.

[0034] Now, a preferred embodiment of the present invention will be explained. In the following explanation, a “lateral direction” of a process cartridge B is referred to as a mounting and dismounting direction of the process cartridge B to and from a main body 14 of an image forming apparatus, which is aligned with a recording medium conveying direction. Further, a “longitudinal direction” of the process cartridge B is referred to as a direction transverse (substantially perpendicular) to the mounting and dismounting direction of the process cartridge B to and from the main body 14 of the image forming apparatus, which is transverse (substantially perpendicular) to the recording medium conveying direction.

[0035] FIG. 1 is an explanatory view showing a construction of an electrophotographic image forming apparatus (laser beam printer) to which an embodiment of the present invention is applied, and FIG. 2 is a perspective view of the image forming apparatus. FIGS. 3 to 5 show a process cartridge to which an embodiment of the present invention is applied. FIG. 3 is a side sectional view of the process cartridge, FIG. 4 is a schematic perspective view of the process cartridge, and FIG. 5 is a perspective view of the process cartridge, looked at from below (lower surface). Further, in the following explanation, the “upper surface” of the process cartridge is referred to as a surface located upward when the process cartridge B is mounted to the main body 14 of the image forming apparatus, and the “lower surface” is referred to as a surface located downward at that time.

[0036] Electrophotographic Image Forming Apparatus A and Process Cartridge B

[0037] First of all, a laser beam printer A as an electrophotographic image forming apparatus to which an embodiment of the present invention is applied will be explained with reference to FIGS. 1 and 2. Further, FIG. 3 is a side sectional view of the process cartridge B.

[0038] As shown in FIG. 1, the laser beam printer A serves to form an image on a recording medium (for example, recording paper, OHP sheet, cloth or the like) by using an electrophotographic image forming process. A toner image is formed on a drum-shaped electrophotographic photosensitive member (referred to as “photosensitive drum” hereinafter). More specifically, the photosensitive drum is charged by charging means, and then, a latent image corresponding to image information is formed on the photosensitive drum by illuminating a laser beam corresponding to the image information from optical means onto the photosensitive drum. The latent image is developed by developing means to form a toner image. In synchronism with the toner image formation, a recording medium 2 is conveyed from a cassette 3aby a pick-up roller 3b, pairs of convey rollers 3c, 3dand a pair of registration rollers 3ewhile reversing a front surface and a rear surface of the recording medium 2. Then, the toner image formed on the photosensitive drum of the process cartridge B is transferred onto the recording medium 2 by applying a voltage to a transfer roller (transfer means) 4. Thereafter, the recording medium 2 to which the toner image is transferred is conveyed to a fixing means 5 via a convey guide 3f. The fixing means 5 includes a driving roller 5c, and a fixing roller 5bhaving a heater 5atherein. By applying heat and pressure to the recording medium 2 passed through the fixing means, the transferred toner image is fixed to the recording medium. Then, the recording medium 2 is conveyed by pairs of discharge rollers 3g, 3h, 3iand is discharged onto a discharge tray 6 through a surface reverse path 3j. The discharge tray 6 is provided on an upper surface of the main body 14 of the image forming apparatus A. Incidentally, by operating a pivotally movable flapper 3k, the recording medium 2 can be discharged by a pair of discharge rollers 3mwithout passing through the surface reverse path 3j. In the illustrated embodiment, the pick-up roller 3b, the pairs of convey rollers 3c, 3d, the pair of registration rollers 3e, the convey guide 3f, the pairs of discharge rollers 3g, 3h, 3iand pair of discharge rollers 3mconstitute conveying means 3.

[0039] On the other hand, as shown in FIGS. 3 to 5, in the process cartridge B, the photosensitive drum 7 having a photosensitive layer is rotated, and a surface of the drum is uniformly charged by applying a voltage to a charging roller (charging means) 8. Then, by illuminating the laser beam corresponding to the image information from an optical system 1 onto the photosensitive drum 7 through an exposure opening portion 1e, the latent image is formed. The latent image is developed by a developing means 9. That is to say, the charging roller 8 is contacted with the photosensitive drum 7 and serves to charge the photosensitive drum 7. The charging roller 8 is rotatingly driven by rotation of the photosensitive drum 7. The developing means 9 serves to develop the latent image formed on the photosensitive drum 7 by supplying toner to a developing area on the photosensitive drum 7. The optical system 1 includes a laser diode 1a, a polygon mirror 1b, a lens 1cand a reflection mirror 1d.

[0040] In the developing means 9, toner in a toner container 11A is fed out to a developing roller 9cby rotation of a toner feeding member 9b. While the developing roller 9cincluding a stationary magnet therein is being rotated, a toner layer is formed on the surface of the developing roller 9cby a developing blade 9dwhile applying a triboelectrification charge to the toner layer, and the toner (layer) is supplied to the developing area on the photosensitive drum 7. By transferring the toner onto the photosensitive drum 7 in accordance with the latent image, a toner image as a visualized image is formed. The developing blade 9dserves to regulate an amount of toner on the peripheral surface of the developing roller 9c. In the vicinity of the developing roller 9c, toner agitating members 9e, 9ffor circulating the toner within a developing chamber are rotatably supported.

[0041] After the toner image formed on the photosensitive drum 7 is transferred onto the recording medium 2 by applying voltage having polarity opposite to that of the toner image to the transfer roller 4, residual toner remaining on the photosensitive drum 7 is removed by a cleaning means 10. In the cleaning means 10, the toner remaining on the photosensitive drum 7 is scraped off by an elastic cleaning blade 10aurged against the photosensitive drum 7, and the scraped-off toner is collected into a waste toner reservoir 10b.

[0042] Incidentally, the process cartridge B is obtained by joining a toner frame 11 having a toner container (toner containing portion) 11A for containing the toner to a developing frame 12 for holding the developing means 9 such as a developing roller 9cto form an assembly and by joining a cleaning frame 13 to which the photosensitive drum 7, the cleaning means 10 such as the cleaning blade 10aand the charging roller 8 are attached to the assembly. The process cartridge B is detachably mountable to the main body 14 of the apparatus by the operator.

[0043] The exposure opening portion 1ethrough which the light corresponding to the image information is illuminated onto the photosensitive drum 7 and a transfer opening portion 13nthrough which the recording medium 2 is opposed to the photosensitive drum 7 are formed in the process cartridge B. More specifically, the exposure opening portion 1eis formed in the cleaning frame 13, and the transfer opening portion 13nis defined between the developing frame 12 and the cleaning frame 13.

[0044] Next, a construction of the housing of the process cartridge B according to the illustrated embodiment will be explained.

[0045] In the process cartridge B according to the illustrated embodiment, the photosensitive drum 7, the charging roller 8, the developing means 9 and the cleaning means 10 are housed in the housing obtained by joining the toner frame 11 to the developing frame to form the assembly and by further rotatably joining the cleaning frame 13 to the assembly. The process cartridge B is detachably mountable to cartridge mounting means provided in the main body 14 of the apparatus.

[0046] Construction of Housing of Process Cartridge B

[0047] As mentioned above, in the process cartridge B according to the illustrated embodiment, the housing is constituted by joining the toner frame 11, the developing frame 12 and the cleaning frame 13. Now, the construction of the housing will be explained.

[0048] As shown FIG. 3, a toner feeding member 9bis rotatably attached to the toner frame 11. Further, the developing roller 9cand the developing blade 9dare attached to the developing frame 12, and the toner agitating members 9e, 9ffor circulating the toner in the developing chamber are rotatably attached in the vicinity of the developing roller 9c. An antenna rod 9his attached substantially in parallel with the developing roller 9calong the longitudinal direction of the developing roller 9c. The toner frame 11 is welded (by ultrasonic welding in the illustrated embodiment) to the developing frame 12 to form a unitary developing unit (second frame) D.

[0049] Further, the photosensitive drum 7, the charging roller 8 and the cleaning means 10 are attached to the cleaning frame 13. A drum shutter member 18 for covering the photosensitive drum 7 to protect the drum from being exposed to the light for a long term and from being contacted with foreign matter when the process cartridge B is dismounted from the main body 14 of the apparatus is further attached to the cleaning frame 13 to form a cleaning unit (first frame) C.

[0050] Construction of Cleaning Unit

[0051] Now, the cleaning means 10 will be described with reference to FIG. 6. The frame 13 for the cleaning means 10 is constituted by a cleaning frame body 13qand a lid 13p. The photosensitive drum 7, the cleaning blade 10a, a dip sheet 10eand the charging roller (charging means) 8 are integrally incorporated into the single cleaning frame body 13q. Further, the waste toner reservoir 10bis provided in the cleaning frame body 13q, and the waste toner reservoir 10bis covered by a cleaning blade metal plate 10c. A dimension of an opening portion 151aof the cleaning frame body 13qcovered by the cleaning blade metal plate 10cis made small so that such an opening portion can be covered by the cleaning blade metal plate 10chaving a small width in the lateral direction.

[0052] Further, as shown in FIG. 7, a strip-shaped seal member 152 is provided for a toner seal between the cleaning blade metal plate 10cand the cleaning frame body 13q. The seal member 152 is adhered to a seal adhering rib 153aof the cleaning frame body 13q. Since the seal member 152 is also adhered to sunken surfaces 153bon both sides of the seal adhering rib 153a, good sealing ability can be achieved. The seal member 152 extends over a substantially entire longitudinal length of the cleaning blade metal plate 10c. Further, between the dip sheet 10eand both longitudinal ends of the cleaning blade metal plate 10c, spaces between the photosensitive drum 7 and the cleaning frame body 13qare sealed by sealing materials (not shown) in the lateral direction, thereby sealing the waste toner reservoir 10b.

[0053] The cleaning blade metal plate 10cabuts against seat portions 13hof the cleaning frame body 13qprovided in correspondence to both longitudinal ends thereof. After the metal plate 10cis inserted, by screwing small screws 10dinto the seat portions 13h, both ends of the metal plate 10care secured to the cleaning frame body 13q. As a result, a distance between the metal plate 10cand the rib (longitudinal ridge) 153ais determined, and thus, compression margin of the seal member 152 having a rectangular cross-section, and having a thickness greater than such a distance is determined. For example, the seal member 152 is made of foam urethane rubber. Incidentally, the seat members 13hare provided with positioning dowels 13h1 by which the position of the cleaning blade metal plate 10cis determined.

[0054] Since the cleaning frame 13 is formed from resin, the conventional molds 154 for a single frame generally comprises a male mold part and a female mold part, respectively, as shown in FIG. 8. When the opening portion 151ais made smaller, as shown in FIG. 9, the waste toner reservoir 10bis also made smaller due to inherent structure of the mold 154. In consideration of the structural feature of the mold, in order to maintain a large waste toner reservoir 10b, as shown in FIG. 10, it is required for providing an opening portion 151btransverse to the opening portion 151a. In this case, the opening portion 151bis covered or closed by the lid 13pof the cleaning frame. The cleaning frame body 13qand the cleaning frame lid 13pare joined together by vibrating welding, ultrasonic welding, adhesive or screws to prevent toner leakage. Further, in a state that the cleaning frame body 13qand the cleaning frame lid 13pare joined together, since the entire cleaning frame has a box shape, a rigidity of the cleaning frame 13 is enhanced, thereby suppressing vibration which affects a bad influence upon image formation.

[0055] Further, as shown in FIG. 11, the cleaning frame lid 13pis provided with a regulating abutment portion 13efor positioning the process cartridge B with respect to the main body 14 of the apparatus. In order to align the cleaning frame lid 13pwith the cleaning frame body 13q, lateral edges on both longitudinal ends of the cleaning frame lid 13pare respectively provided with positioning portions (downwardly directing projections) 155a, which positioning portions 155aare fitted into cut-away portions 155bformed in edges on both longitudinal ends of the cleaning frame body 13q.

[0056] With this arrangement, the cleaning frame lid 13pcan be positioned with respect to the cleaning frame body 13qby a center 155cdefined by a straight line perpendicular to a welding surface 156 (interface between the cleaning frame lid 13pand the cleaning frame body 13q) and passing through a position bisecting each positioning portion 155ain the lateral direction. In this arrangement, it is selected so that extension of the regulating abutment portion 13eof the cleaning frame lid 13p, the center 155cof the positioning portion 155aof the cleaning frame lid 13p, the welding surface 156 pass through the same point P, as shown in FIG. 11. Since the positioning relationships pass through the same point P, after the cleaning frame lid 13pand the cleaning frame body 13qare welded together, positioning accuracy of the process cartridge B with respect to the main body 14 of the image forming apparatus is enhanced.

[0057] Further, as shown in FIG. 12, a rib 157 is provided in the cleaning frame body 13qalong its entire longitudinal length as a reinforcing member for the cleaning frame. The rib 157 extends along the entire longitudinal length and is spaced apart from a front end (deep side) wall 13rof the cleaning frame body 13qby 0.5 to 15 mm. The distance between the wall 13rand the rib 157 is preferably 0.5 to 3.0 mm. By providing such a distance (gap) 158, transfer of heat from the wall is prevented, and, as shown in FIG. 13, if the waste toner T′ is accumulated, the waste toner T′ can drop toward the deep side through this gap 158. The rib 157 has a thickness of 1 to 4 mm and a width of 5 to 40 mm. As shown in FIG. 14, if there is no rib 157, when the wall 13rof the cleaning frame 13 near the fixing means 5 (heat source) is heated to try to be abruptly expanded, due to difference in thermal expansion between the abruptly heated portion and non-heated portion, deformation of the cleaning frame 13, and, particularly, deformation of attachment portions 162 for the cleaning blade 10a(important for cleaning) will occur. By providing the rib 157, such deformation can be suppressed, thereby providing a cleaning frame having great resistance against thermal deformation.

[0058] As another embodiment improving the above-mentioned arrangement, as shown in FIG. 15, in place of the rib, a metal plate 159 may be used so that the metal plate is secured to both ends 13sin the cleaning frame body 13qby small screws 159a.

[0059] Further, since there is difference in coefficient of thermal expansion between the cleaning frame 13 made of resin and the cleaning blade metal plate 10cmade of metal, as shown in FIG. 12, in order to permit slight sliding movement between the cleaning frame 13 and the cleaning blade metal plate 10cwhen the cleaning unit is heated, the cleaning blade 10ais secured by small screws 10dvia resin washers 160. Incidentally, the washers 160 may be made of nylon.

[0060] As shown in FIGS. 5 and 16, the developing frame 12 is provided at its lower surface with the guide ribs 129 and the cleaning frame 13 is provided at its lower surface with the guide ribs 13m, which ribs 129, 13mare constituted by ridges extending along the moving direction of the recording medium 2. The guide ribs 12t, 13mare situated slightly inside (about 5 mm in the illustrated embodiment) of both longitudinal ends of the recording medium 2. Additional guide ribs for aiding the conveyance of the recording medium are provided at other positions. The electrophotographic image forming apparatus A according to the illustrated embodiment can form images on recording media 2 having various sizes and can convey any recording medium 2 to pass the recording medium through a central portion of the image forming apparatus (center line CL of the apparatus coincides with the center of the recording medium 2). To this end, in the illustrated embodiment, the developing frame 12 and the cleaning frame 13 are provided at their lower surfaces with plural ribs which are symmetrical with respect to a center line CL. Heights of ribs in the developing frame 12 are predetermined and heights of ribs in the cleaning frame 13 are also predetermined to convey the recording medium advantageously. With this arrangement, a non-fixed toner image is prevented from being contacted with the lower surface of the cleaning frame 13 to prevent distortion of the image, while improving the conveyance of the recording medium.

[0061] FIG. 16 shows various dimensions from the center line CL as numerical values (unit: mm), as an example of the illustrated embodiment (only one side). Symbols of standard papers (Japanese Industrial Standards) of the recording medium 2 corresponding to the respective numeral values are indicated. For example, A3L indicates a case where a longitudinal direction of a recording medium having A3 size becomes a conveying direction, and A4S indicates a case where a lateral direction of a recording medium having A4 size becomes a conveying direction. Further, ENV corresponds to a recording medium 2 having an envelope size and EXE corresponds to a recording medium 2 having e ecutive size. Incidentally, the guide ribs 12lor(and) 13mdisposed at distances of 5.0 mm, 13.0 mm and 28.0 mm from the center line CL support a central area of the recording medium 2.

[0062] Incidentally, unlike the aforementioned embodiment, in this embodiment, the guide ribs 13mhave heights gradually increasing toward outside, and the each pair of ribs 13mcorresponding to each recording medium have the same height. With this arrangement, the inner ribs can surely be prevented from contacting with the imaged surface of the recording medium, thereby avoiding the distortion of the image positively. Also in this case, the disposition of the ribs in the same as the case where the ribs have the same height.

[0063] According to the present invention, the cleaning frame has the reinforcing member provided in the waste toner chamber and reaching to both end walls of the body of the cleaning frame with respect to the longitudinal direction of the electrophotographic photosensitive drum substantially in parallel with the electrophotographic photosensitive drum and defining the gap between the reinforcing member and the wall of the waste toner chamber opposed to the electrophotographic photosensitive drum. With this arrangement, if the wall of the waste toner chamber opposed to the electrophotographic photosensitive drum is heated and expanded by the heat from the thermal fixing device, since both end walls of the cleaning frame (with respect to the longitudinal direction of the electrophotographic photosensitive drum) are interconnected by the reinforcing member through which the heat from the thermal fixing device is difficult to be transferred, deformation of both end walls of the cleaning frame is suppressed.

[0064] When the reinforcing member is molded-integrally with the cleaning frame, the number of assembling steps and the assembling time are not increased.

[0065] When the reinforcing member is made of metal, rigidity of the cleaning frame is increased.

[0066] According to the process cartridge and the electrophotographic image forming apparatus having such a cleaning frame, since the process cartridge can be installed in the vicinity of the fixing means, the main body of electrophotographic image forming apparatus can be made more compact.