Cleaner for an Electrophotographic Copying Machine

The present invention relates to a cleaner for an electrophotographic copying machine generating pictures using toner, which is capable of removing residual toner from the surface of the photoreceptor following the discharge procedure.

Conventional copying machines which generate pictures using toner let the toner-absorbing photoreceptor continuously perform all photocopying operations. In other words, the surface of the photoreceptor that passes through the copying steps of "charge, light exposure, development, transfer, and discharge" is recharged and completes these steps again before performing the next copying operation. In the developing process, the toner absorbed by the surface of the photoreceptor is not fully transferred onto the papers being copied and part of the toner remains on the surface of the photoreceptor. If the next copying operation is executed using a photoreceptor containing residual toner, the toner tends to adhere to a portion of the copied paper other than the picture, thus making it difficult for the copy machine to correctly and cleanly complete the necessary copying operation. In order to accurately copy the original continuously, it is necessary to completely remove residual toner from the discharge-completed portion of the photoreceptor surface. Conventional electrophotographic copying machines include a cleaner with a blade made of elastic material which scrapes the residual toner from the surface of the photoreceptor between the discharge-charger and the charger-charger. The flecks of toner then traverse a screw shaft into a container mounted between the front cabinet and the front frame where a limited quantity of dislodged toner is stored until cleaning. Some conventional copying machines also provides a container below the cleaning unit which catches toner scraped by the blade. Such conventional cleaning methods require removal of the container when extracting clogged paper from the unit. Even when using an electrophotographic copier which integrates various copying machinery into one unit that can be easily attached or detached from the copying machine, it is necessary to remove the toner collection container to service the unit properly. The capacity of the toner collection container is limited by the confined space between the front cabinet and the front frame on standard copiers. Even when using the advanced integrated copying mechanism mentioned above, the capacity of the toner collection container is also limited due to space constraints. Consequently, when copying a large number of papers, even before general maintenance is required, residual toner may build up inside the container, inconveniencing clients who are forced to replace the stained container.

In the light of the disadvantages of conventional copying machines, the present invention aims at providing a useful cleaner for electrophotographic copying machines capable of relieving clients of the chore of replacing the toner container. This invention will serve the user by implementing the installation of a toner collection container in a specific position where the container capacity is not restricted. The present invention will make transfer or removal of the container unnecessary when copy paper jams the paper-feed path or while servicing other copying parts. In addition by increasing the storage capacity of the toner collection container itself, regularly scheduled maintenance will provide sufficient opportunity to empty or replace the full container. Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description of and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In brief, the present invention provides a cleaner unit for an electrophotographic copying machine in which the aperture of the toner collection container rests at a position above the bottom surface of the cleaner. A conveyer piece is installed inside the cleaner unit, between said container aperture and the aperture of the cleaning unit adjacent the photoreceptor. A guide plate brings the tip of the conveyer member into contact with the bottom of the cleaner unit when the conveyer member moves in the direction of the aperture of the toner collection container and conversely prevents the tip of the conveyer member from coming into contact with the bottom of the cleaner unit when the conveyer member moves in the direction of the photoreceptor aperture.

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein:

FIG. 1 is a sectional view representing the simplified structural design of a cleaner device for an electrophotographic copying machine embodied by the present invention;

FIGS. 2A-and-B are operation diagrams of a conveyer member used for the preferred embodiment of the present invention;

FIG. 3 is a diagrammatical cross-sectional view along line 3--3 of FIG. 5 of the guide plate used for the preferred embodiment of the present invention;

FIG. 4 is a schematic view of a drive force transmission mechanism embodied by the present invention; and

FIG. 5 is a plan view representing the simplfied design of the cleaner embodied by the present invention.

Referring to the accompanying drawings, the preferred embodiments of the present invention are described below. FIG. 1 is the simplified structural diagram of the cleaner unit for the electrophotographic copying machine reflecting the preferred embodiments of the present invention.

Cleaner unit 7 is installed between discharge-charger 9 and charger 20 so that it faces photoreceptive drum 1. Container 8 is located in a position opposite photoreceptor 1 of cleaner unit 7. The upper surface of container 8 lies flush with the upper surface of cleaner unit 7, whereas the bottom surface of container 8 is at the lowest position possible without interfering with the copy-paper path (not shown). Blade 4 is attached to the upper portion of aperture 7a on the photo-receptor part of the cleaner unit 7 with metal brace 6. The tip of blade 4, made of elastic material, comes in contact with the surface of photoreceptive drum 1. This allows blade 4 to slide over the surface of the photoreceptor when the photoreceptive drum 1 moves in the direction of arrow A (while the photocopying operation is underway) so that residual toner adhering to the surface can be scraped clean. The dislodged toner is contained solely on surface 3 of cleaner unit 7 by means of shield 18 attached to the photoreceptor side of the bottom surface of cleaner unit 7. Cleaner unit 7 includes conveying member 2, which pivots in the following manner: conveying member 2, is put into motion by the conveying member driving mechanism described below and it returns to its starting position in the direction of arrow C or arrow C' between the positions shown by solid line and broken line 2'.

FIGS. 2 (A) and (B) are the operation diagrams of the conveyer mechanism inside the cleaner unit of the electrophotographic copying machine described above. The top end of conveyer member 2 is designed to move in conjunction with member 2c via pivot 2b. Both conveyer member 2 and member 2c are returned in the arrowed directions D and D', respectively, by means of return spring 10 attached to pivot 2b. Projection 2a on the lateral surface of member 2c controls movement of the tip portion of member 2c by coming into contact with guide plate 12 (described below). Referring to FIG. 2 (A), when the conveyer member 2 moves from aperture 7a in the direction of arrow C to position 2' (broken line) near container aperture 8a, the tip of member 2c comes into contact with surface 3 to move stored residual toner through aperture 8a of the container. Referring to FIG. 2 (B), when conveyer member 2 moves in the direction of arrow C' from aperture 8a of the container to aperture 7a of the photoreceptor, the tip of member 2c does not come in contact with surface 3 of cleaner unit 7, but remains in position 2" (broken line of the drawing.) As a result, due to the spring return movement 10 of conveyer member 2, the tip of member 2c moves along the broken-line track shown in FIG. 2 (B). FIG. 3 is a sectional view of guide plate 12 of cleaner unit 7 of said electrophotographic copying machine. Guide plate 12 is composed of members 12a and 12b which are positioned to form a curve corresponding to surface 3 of cleaner unit 7. Elastic member 11 is positioned at the end of the path between member 12a and member 12b. When projection 2a of conveyer member 2 moves in the direction of arrow C, between members 12a and 12b of guide plate 12, it stretches elastic material 11 until member 2 reaches a position very close to area 12C of guide plate 12. Projection 2a then passes between elastic material 11 and member 12a, and returns in direction C" along the upper surface of member 12b. Thus guide plate 12 provides flexible foward and backward movement of conveyer member 2. Using the elastic force of return spring 10, projection 2a maintains its position between members 12a and 12b in direction C, and against member 12b in direction C".

FIG. 4 is a structural diagram of the drive force transmission mechanism used for cleaner unit 7 of the electrophotographic copying machine. Drive gear 16 is connected to drive shaft 17. Momentum is transmitted to gear 15 when it is engaged with drive gear 16. Projection 15a, on the lateral surface of transmission gear 15, meshes with guide groove 14a of reciprocating gear 14. Transmission gear 13 engaged with the reciprocating gear 14 is secured to shaft 2d of conveyer member 2. When drive shaft 17 rotates in the arrowed direction E, transmission gear 15 rotates in the arrowed direction F. Simultaneously, since the projection 15a and the guide groove 14a are engaged with each other, reciprocating gear 14 moves back and forth between the directions of arrows G and G'. The reciprocating drive force is then transmitted to shaft 2d of conveyer member 2 via transmission gear 13.

FIG. 5 is the plan view representing the simplified structure of the cleaner of the electrophotographic copying machine.

A pair of guide plates 12 are installed facing each other inside frames 23 and 24 of the electrophotographic copying machine to support photoreceptive drum 1 via a shaft. Projection 2a of the conveying member 2 rests on guide plate 12. Shafts 2d of conveyer member 2 are both supported by the cleaner unit (not shown in FIG. 5.) The shaft of frame 24 is provided with this drive force transmission mechanism.

Actual operations of the preferred embodiment are described below. The part of the surface of photoreceptive drum 1 which just completed the discharge process during the photocopying operation comes into contact with the tip end of blade 4 of the cleaner, which scrapes residual toner from the surface. Scraped toner falls to surface 3 of cleaner unit 7 through aperture 7a of photoreceptive drum 1. At the same time, rotation of the drive shaft 17 receiving momentum from the main motor (not shown in the accompanying drawings) is converted into reciprocating movement, which is then transmitted to shaft 2d of conveyer member 2. This transission of momentum permits conveying member 2 to execute the reciprocating movement in the directions of arrows C and C'. As a result of the engagement of projection 2a with the lateral surface of member 2c at guide plate 12, the tip of member 2c comes into contact with surface 3 of cleaner unit 7 when conveyer member 2 moves in the direction of aperture 8a. This action pushes stored toner in the direction of aperture 8a of the collection container and into the container itself. Because of return spring 10, when conveying member 2 moves in the direction of the aperture of the photoreceptor (7a), the tip of member 2c does not touch surface 3 of cleaner unit 7. Toner scraped from the surface of photoreceptive drum 1 by blade 4 is never pushed in the direction of aperture 7a of the photoreceptor. By this method its is possible for the system to convey the scraped toner to aperture 8a, even through the aperture is located slightly above surface 3. The installation of a container of sufficient capacity in a position opposite the photoreceptor of the cleaner unit not only simplifies repair and maintenance procedures but also enables an increase in the storage capacity of the residual toner collection container.

As is clear from the above description, the preferred embodiment of the present invention makes it possible for an electrophotographic copying machine to utilize a residual toner collection container of sufficient size to dispense with the need to move or remove the container when performing routine repair or maintenance services. The useful design also prevents the container from becoming full of scraped toner prior to regularly scheduled maintenance service. Consequently, users can be freed from the complicated and inconvenient task of replacing the stained container, a significant improvement in service for the consumer.

While only certain embodiments of the present invention have been described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as claimed.