Abstract:
A cleaning apparatus for an image carrier includes a cleaning member for removing remaining developer left on the image carrier; and a sealing member disposed on each opposite end of the cleaning means for preventing the developer removed by the cleaning member from leaking out. The sealing member cleans a surface to which a distance-ensuring device for maintaining a prescribed distance between the image carrier and another electrophotographic process means, extends, and contacts with the image carrier.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a process cartridge using an electrophotographic method or an electrostatic recording method and an image forming apparatus using the process cartridge. 
     2. Description of Related Art 
     To form images, image forming apparatuses using an electrophotographic method or an electrostatic recording method form, by selective exposure, latent images on an image carrier, uniformly charged, serving as an electrophotographic photosensitive body by a charging means, visualize the latent images by a developing means, and transfer the developed images onto a recording medium. After the developed images are transferred, remaining developer (hereinafter referred to as “waste toners”) left on the image carrier is cleaned by a cleaning means and reused for image formation upon being charged uniformly. 
     A process cartridge has been practically used recently in which process means, such as charging means, developing means, cleaning means, a cleaning container, and so on, are made in a united structure. A user can replace the parts, such as the developers, the image carrier, and so on with those by placing the process cartridge in the apparatus body, thereby rendering the maintenance easier. 
     Since the image carrier generally has extended the life time of the carrier, recently favored usage, which renders the maintenance easier and corresponds to life times of the essential parts is done by designing a developing means, having some limitation for supplying capability, into an independent cartridge and by designing the remaining process means, such as an image carrier, a charger, a cleaning means, and so on, into a drum cartridge, in a united body. 
     FIG. 4 shows an example of a conventional process cartridge. The process cartridge  100  shown in FIG. 4 is the above drum cartridge, which includes an image carrier  101 , a cleaner blade  102  serving as a cleaning means, and a cleaning container  104  accumulating the waste toners. 
     The cleaner blade  102  has an elastic contact portion  102   a  supported by a support member  102   b  in contact with the image carrier  101  and removes the waste toner remaining on the surface of the image carrier  101 . A sealing member  103  made of a material such as mortoprain, sponge, felt, or the like is provided on the opposite ends of the cleaner blade  102  to prevent the waste toner from leaking out of the cleaning container  104 . The cleaning container  104  has a volume capable of adequately containing waste toner occurring at the cleaner blade  102  within the life time of the image carrier  101 , and can be removed at the time of replacement of the drum cartridge. 
     Particularly, in a case of a development method using a jumping development or magnetic brush development, it is important to position a developer carrier (development sleeve) for developing images with high accuracy at a prescribed distance with respect to the image carrier  101 . Therefore, a contacting roller  105  or the like as a distance ensuring means manufactured with high accuracy is generally placed on each end of the image carrier to ensure the proper distance between the image carrier  101  and the development sleeve (not shown). 
     In such a case, if the contacting surface  101   a  of the contacting roller  105  on the image carrier  101  becomes dirty with scattered toner, the toner may adhere to the contacting surface  1 O 1   a , and the prescribed distance may not be kept, disadvantageously. Therefore, the placement of a cleaning member  106 , as a part separated from the sealing member  103  provided on the opposite ends of the cleaner blade  102 , has been implemented recently for cleaning the contacting surface  101   a  of the contacting roller  105 . 
     Where the sealing member  103  and the cleaning member  106  are separated members, as shown in the apparatus in FIG. 4, however, developers may accumulate on unclean areas particularly in the process cartridge having a longer life time because the space between those members  103 ,  106  cannot be cleaned, and the accumulated developers may drop into the apparatus body to disadvantageously make the apparatus inside dirty. 
     It is therefore an object of the invention to provide a cleaning apparatus, a process cartridge, and an image forming apparatus reducing the uncleanness inside the apparatus by proposing a cleaning method for the surface of the image carrier having no unclean area. 
     SUMMARY OF THE INVENTION 
     To solve the above problems, a representative structure of the cleaning apparatus, according to the invention, includes a cleaning member for removing a remaining developer left on the image carrier, and a sealing member disposed on each opposite end of the cleaning means for preventing the developer removed by the cleaning means from leaking out, the sealing member cleaning a surface to which a distance-ensuring means, for maintaining a prescribed distance between the image carrier and another electrophotographic process means, extends and contacting the image carrier. 
     Since the sealing member that is provided on each opposite end of the cleaning means is extended to a surface on the image carrier contacting the distance-ensuring means for cleaning the surface, the process cartridge can eliminate an area at which scattered toner arrives, so that the process cartridge can reduce the uncleanness inside the apparatus. Because the members are made in a united body, the number of parts is reduced, and the manufacturing process and the cost of parts of the cleaning apparatus can be reduced, so that the productivity can be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an entire structural view showing an image forming apparatus according to an embodiment of the invention; 
     FIG. 2 is a front view showing a process cartridge according to an embodiment of the invention; 
     FIG. 3 is a side view of a sealing member: and 
     FIG. 4 is a front view showing a conventional process cartridge. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to FIGS. 1,  2 , a process cartridge and an image forming apparatus of embodiments according to the invention are described. 
     [Whole Structure] 
     The image forming apparatus  1  shown in FIG. 1 is a color laser printer. As shown in FIG. 1, the image forming apparatus includes an image carrier  15  rotating at a fixed rate, an image forming section made of a secured black developing unit  21 K and a rotary developing unit  20  having three color developing units, an intermediate transfer body  9  for holding color images developed and overlapped at the image forming section and transferring the images onto a recording medium S fed from a feeding section. The recording medium S on which color images are transferred is conveyed to a fixing section  25 , and the images are fixed on the medium under the application of heat and pressure. The recording medium S is then delivered by a delivery roller to a delivery section  37  located at a top surface of the apparatus body. It is to be noted that the rotary developing unit  20  and the immobilized black developing unit  21 K are constituted respectively to be detachably attached to the body of the image forming apparatus  1 . Each section of the image forming apparatus  1  will be described in detail next. 
     The drum cartridge  13  is constituted in a united body of the image carrier  15 , and a cleaning container  14  also serving as a holder for the image carrier  15 . The drum cartridge  13  is supported detachably to the apparatus body and can be replaced as a unit basis easily in accordance with the life time of the image carrier  15 . In this embodiment, the image carrier  15  is constituted of an aluminum cylinder having a diameter of about 62 mm coated with an organic photo-conductive layer and is rotatively mounted. A cleaner blade  16  serving as a cleaning member, and a primary charging means  17  are disposed on a periphery of the image carrier  15  and are rotatively drive by a drive force from a drive motor, not shown, according to an image formation operation. The cleaning container  14  is as described below. 
     The primary charging means  17  uses a contact-charging method, in which a conductive roller is made to be in contact with the image carrier  15 . The surface of the image carrier  15  can be charged uniformly by the application of a voltage to the conductive roller. 
     The image carrier  15  is subject to exposure at a scanner section  30 . That is, when an image signal is given to a laser diode, the laser diode radiates image light corresponding to the image signal to a polygon mirror  31 . The polygon mirror  31  rotates at a high rate by a scanner motor, not shown, and the image light reflected on the polygon mirror  31  selectively expose the surface of the image carrier  15  rotating at a fixed rate through image forming lenses  32  and a reflex mirror  33 , thereby forming static latent images on the image carrier. 
     The developing means is constituted of the rotary developing unit  20  having the respective color developing units, a yellow developing unit  20 Y, a magenta developing unit  20 M, a cyan developing unit  20 C, and a sole black developing unit  21 K. 
     The black developing unit  21 K is a secured developing unit. A sleeve  21 KS is disposed with a very small space to the image carrier  15  at a position corresponding to the image carrier  15  and forms visible images on the image carrier  15  by black toner. The black developing unit  21 K feeds toner in the container by a feeding mechanism, coats the toner as a thin layer on an outer periphery of the sleeve  21 KS rotating in a clockwise direction in FIG. 1 by a coating blade  21 KB, made in pressed contact with an outer periphery of the sleeve  21 KS, and gives electric charges to the toner. When a development bias is applied to the sleeve  21 KS, the electrostatic latent image of the image carrier  15  is developed with the toner. 
     The rotary developing unit  20  is supported detachably to a development rotary member  23  rotating around a shaft  22  as a center, and for forming images, the respective developing units move rotationally around the shaft  22  and stop the rotation at a position such that a predetermined developing unit faces the image carrier  15 . After sleeves  2 OYS,  2 OMS,  20 CS are positioned to face the image carrier  15  with a very small space (about 300 μm), visible images are formed corresponding to the electrostatic latent images on the image carrier  15 . When a color image is formed, the developing rotary member  23  rotates as one rotation of the intermediate transfer body  9 , and a developing process is done by means of the yellow developing unit  20 Y, the magenta developing unit  20 M, the cyan developing unit  20 C, and the sole black developing unit  21 K, in this order, so that each color is transferred to the intermediate transfer body  9  and overlapped at the body  9 . After the toner images are transferred onto the intermediate transfer body  9 , the developer remainders, which remain on the image carrier  15 , or namely the waste toner, are removed by the cleaning means as described below. 
     FIG. 1 shows a state that the yellow developing unit  20 Y is placed and made still at a position that the unit faces to the image carrier unit. The yellow developing unit  20 Y feeds the toner in the container to a coating roller  20 YR by a feeding mechanism, coats the toner as a thin layer on an outer periphery of the sleeve  20 YS rotating in a clockwise direction in FIG. 1 by means of the coating roller  20 YR rotating in a clockwise direction in FIG. 1 and a coating blade  20 KY, and gives electric charges (triboelectric charges) to the toner. By application of the development bias to the sleeve  20 YS facing the image carrier  15  on which latent images are formed, development is made with toner on the image carrier  15  corresponding to the latent images. Image formation for respective colors is made in substantially the same way with respect to the magenta developing unit  20 M and the cyan developing unit  20 C. 
     The sleeves  20 YS,  2 OMS,  20 CS of the rotary developing unit are connected to a drive power and respective high voltage sources for the respective colors formed in this printer body when each developing unit moves rotationally to the developing position, and the voltage is selectively and sequentially applied for each color developing unit where each unit is driven. 
     The intermediate transfer body  9  rotates in the clockwise direction in FIG. 1 in synchrony with the outer peripheral speed of the image carrier  15 , and receives multiple transfers by four transfers (images of four colors, CMYK) of visualized toner images on the image carrier  15  by the respective developing units when color images are formed. The intermediate transfer body  9  that received the multiple transfers further transfers the color toner images on the intermediate transfer body  9  at one time onto the recording medium S by conveying the recording medium S through sandwiching the medium S with the transfer roller  10  to which the voltage applies. 
     The intermediate transfer body  9  according to the embodiment has an aluminum cylinder  12  having a diameter of 186 mm and an outer periphery covered with an elastic layer  11  made of materials such as an intermediate resistance sponge and intermediate resistance rubber. The an intermediate transfer body  9  is rotatively supported and rotates upon transmission of drive force by means of gears, not shown but secured unitedly 
     The recording medium S is stacked on a cassette  2  provided at a lower portion of the apparatus body. The recording medium S, after being fed by a pickup roller  3  and separated by a feeding roller  4  and a retard roller  5  sheet by sheet, is conveyed by guided by a feeding guide  6  and sent to the register roller  8 . The register roller  8  does a non-rotation operation that renders the recording medium S in a stop and wait state and a rotation operation that renders the recording medium S conveyed toward the intermediate transfer body  9  according to a prescribed sequence, thereby correcting oblique feeding of the recording medium S and conveying the recording medium S in synchrony with the intermediate transfer body  9 . 
     The transfer roller  10  winding an intermediate resistance foamed elastic body over a metal shaft is provided to be capable of contacting with and separating from the intermediate transfer body  9 . While the four color toner images are formed on the intermediate transfer body  9 , or while the intermediate transfer body  9  turns multiple times, the transfer roller  10  is located at a position spaced from the intermediate transfer body  9  as shown by a solid line in FIG. 1 so as to keep the images in order. When the recording medium S is conveyed after the color toner images are formed on the intermediate transfer body  9 , the transfer roller  10  is urged with a prescribed pressure to the intermediate transfer body  9  through a recording medium S as shown by a broken line by means of a cam not shown. 
     A bias is also given to the transfer roller  10  at that time, thereby transferring the toner images on the intermediate transfer body  9  to the recording medium S. The intermediate transfer body  9  and the transfer roller  10  are driven respectively, so that the recording medium S is in a state that sandwiched by the intermediate transfer body  9  and the transfer roller  10 , is subject to a transfer process and at the same time, is conveyed at a prescribed rate toward the fixing section  25  as the subsequent process. 
     The fixing section  25  is for fixing the toner images transferred on the recording medium S and includes a fixing roller  26  for applying heat, and a pressure roller  27  for pressing the recording medium S to the fixing roller  26 . The respective rollers  26 ,  27  are hollow rollers and have respective heaters  28 ,  29  inside, thereby conveying the recording medium S upon being rotatively driven. 
     That is, the recording medium S holding toner images is conveyed by the fixing roller  26  and the pressure roller  27 , and when heat and pressure are applied, the toner images are fixed on the recording medium S. The recording medium S to which the images are fixed is conveyed by a conveyance roller  34  and a conveyance roller  35  and is delivered to the delivery section  37  by a delivery roller  36  to be stacked, thereby finishing the image formation. 
     [Process Cartridge] 
     Referring to FIG. 2, the drum cartridge  13  as a process cartridge according to the invention is described next. The drum cartridge  13  as described above is constituted of an image carrier  15 , and a cleaning container  14  for accumulating in the cleaning container  14  waste toners removed from the image carrier  15 . 
     Cleaning processing is made by the cleaner blade  16  attached to the cleaning container  14  and a cleaning blush not shown. The waste toners on the image carrier  15  enter in the cleaning container  14  by going by a scooping sheet  18 , and are scraped by first the cleaning brush and then the cleaner blade  16 . The scraped waste toners are scooped up by the scooping sheet  18  and collected in the cleaning container  14 . The cleaning container  14  may not be filled with the waste toner accumulated in the container  14  earlier than the life time of the image carrier  15 , so that the cleaning container  14  can be replaced together at a time of replacement of the image carrier  15  when reaching the life time. 
     In the cleaning container  14 , a support member  16   b  is so secured at a front surface of the cleaning container  14  by securing members  40  such as screws or the like that an elastic contacting portion  16   a  of a tip of the cleaner blade  16  is in contact with the image carrier  15  with a prescribed entering amount. 
     A sealing member  41  for preventing the waste toners from leaking out of the cleaning container  14  is attached on each opposite side of the cleaner blade  16  on the cleaning container  14  as to contact the image carrier  15 . As a sealing member  41 , it is preferable that the surface contacting with the image carrier  15  has sealing property and sliding property, and in this embodiment, a fabric member, in which a PTFE fiber is formed in a pile shape, is used as the sealing member. The sealing member can be any material as long as it has the required sealing property and sliding property so that, for example, a fabric member of an electrostatic transplant, felt, or the like may be used. To prevent the sealing property from being impaired, the sealing member preferably has a double-layered structure in which a cushion material, such as foamed urethane or the like, is provided on the back surface of the sealing member. 
     A contacting roller  42  serving as a distance-ensuring means, manufactured with high accuracy, is disposed at a position corresponding to each end of the image carrier  15 , and is rotatively supported around a roller shaft  42   a . The contacting roller  42  is in contact with the image carrier and the sleeves  20 YS,  20 MS,  20 CS, and  21 KS and ensures the prescribed distance between the image carrier and the sleeves. 
     The sealing member  41  is molded as to extend up to the opposite end of the image carrier  15 , and includes a sealing portion  41   a  serving as a seal, and an extended portion  41   b . Therefore, the sealing portion  41   a  functions as to prevent the waste toners from leaking out, and the extended portion  41   b  is in contact with the contacting surface  15   a  on the image carrier  15  contacting to the contacting roller  42  and cleans the contacting surface. Accordingly, even where foreign objects, such as scattered toners, are attached between the contacting roller  42  and the contacting surface  15   a , the surface can always keep the state by wiping the surface with the extended portion  41   b , so that the apparatus can maintain the distance between the image carrier  15  and the sleeve. 
     Because the extended portion  41   b  is in a united body with the sealing portion  41   a , there is no space between the sealing member and the cleaning member, so that the image carrier may not have any space on which scattered toners remain. The number of parts to be attached is further reduced, so that the process cartridge can reduce the manufacturing process and the costs for parts and can improve the productivity as well. 
     With the above embodiments, the fabric member is used as the sealing member  41 , and the form of the fabric member is illustrated in reference to FIG.  3 . FIG. 3 shows a plan view and side view of the fabric member, and the plan view located above shows a part in FIG. 2 in an enlarged view. Numeral  16   b  in the plan view is a receiving sheet for toner made of a thin film sheet, and the sheet is attached and secured below the blade  16   a  of the cleaning housing  14 . That is, the toner scraped by the blade  16   a  are guided and collected by the receiving sheet into the cleaning housing. 
     Innumerous fabrics  41   c , constituting the fabric member, are inclined toward the opening made of the blade  16   a  of the housing, the sealing member  41 , and the receiving sheet  16   b , as shown in the side view located below in FIG. 3. A permissive range of the inclined state may be, as shown in this plan view, as far as within 90° with respect to the opening side, and preferably, within 45° to 60°, which would be no problem. 
     The effects for preventing the toner from scattering and for cleaning portions corresponding to the roller of the developing roller can be adequately accomplished where the fabric member  41  is inclined toward the opening and where the inclined direction is within the above range even if shifted. 
     Particularly, where the fabric member is inclined, the toners about to scatter from the opening side can be captured, and at the same time, the inclined fabrics can improve the above cleaning effect. 
     It is to be noted that as another example equivalent to the above roller  42 , the roller shaft  42   a  in FIG.  2  and as a developing roller, a spacer formed on each opposite end of the roller  42  may be used. In addition, a spacer member or members provided to a charger, a transfer unit, or an intermediate transfer unit around the vicinity of the image carrier when necessary are very useful. 
     The sealing member disposed on each opposite end of the cleaning means is structured to extend to a surface to which a distance-ensuring means disposed on the image carrier contacts, to clean it, and therefore, in comparison with a structure that a cleaning member, for cleaning the contact surface of the distance ensuring means, is newly added, no slight gap (uncleaned area) may be otherwise provided between the sealing member and this cleaning means, so that the scattered toner clinging to that portion could further completely eliminate a worrisome mess on the transfer roller, serving as the transfer means, and ends of the transfer materials. 
     Since the sealing member (cleaning member) covers entirely an interval between the cleaning means and the distance-ensuring means, the cleaning distance to the distance-ensuring means can be used most effectively, and the cleaning means can be utilized as a cleaning means having a longer life time. 
     The above structure has separated functions for substantially preventing leaks and for cleaning, so that a longer life time can be provided. 
     Since the sealing member and the cleaning member are made in a united body, assembling of the members can be made simpler, and this can reduce the costs for assembling and mistakes such as the assembling being made negligently without necessary parts.