Abstract:
A remanufacturing method for a process cartridge includes (a) removing the second end cover at the other longitudinal ends of the drum frame, the developing frame and the developer frame; (b) removing a drum shaft rotatably supporting the drum; (c) separating the drum and the developing roller from each other; (d) moving the drum outwardly from the process cartridge, so that the drum is inclined, and then removing the drum from the drum frame; (e) inserting one end of a new drum such that a driving force receiving portion is exposed outside the drum frame, and inserting the drum shaft from outside of the drum frame; (f) opening a filling port provided in the developer accommodating portion, refilling the developer and then closing the filling port; and (g) fixedly mounting a second end cover to the other longitudinal ends of the drum frame, the developing frame and the developer frame.

Description:
FIELD OF THE INVENTION AND RELATED ART 
   The present invention relates to a process cartridge remanufacturing method. Here, a process cartridge is a cartridge in which a minimum of a developing means and an electrophotographic photoconductive member are integrally disposed, and which is removable mountable in the main assembly of an electrophotographic image forming apparatus. 
   An electrophotographic image forming apparatus includes an electrophotographic copying machine, an electrophotographic printer(for example, an LED printer, a laser beam printer, and the like), an electrophotographic facsimile, an electrophotographic word processor, and the like. 
   In an electrophotographic image forming apparatus, a process cartridge system has long been employed. According to this system, an electrophotographic photoconductive member, and a single or a plurality of processing means, which act on the electrophotographic photoconductive member, are integrated into the form of a cartridge removably mountable in the main assembly of the image forming apparatus. This system enables a user him/her self to maintain the apparatus without relying on a service person, immensely improving the operability of the apparatus. Thus, the process cartridge system has been widely used in the field of an image forming apparatus. 
   A process cartridge such as the one described above forms an image on a recording medium with the use of developer (toner) contained therein. Therefore, the amount of the developer therein gradually decreases with image formation, eventually to a level below which it fails to form an image satisfactory in quality to the user who purchased the process cartridge. At this point, the process cartridge loses its commercial value. 
   Thus, it has long been desired to realize a simple method for remanufacturing a process cartridge so that a process cartridge which has lost its commercial value due to the depletion of the developer therein can be marketed again. 
   SUMMARY OF THE INVENTION 
   The primary object of the present invention is to provide a simple method for remanufacturing a process cartridge. 
   Another object of the present invention is to provide a method for remanufacturing a process cartridge, the commercial value of which has been lost due to the consumption of the developer therein to a level below which the process cartridge fails to form an image satisfactory in quality to a user who has purchased the process cartridge. 
   According to an aspect of the present invention, there is provided a remanufacturing method for a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, wherein the process cartridge includes a drum frame supporting an electrophotographic photosensitive drum and having at one end a driving force receiving portion for receiving a driving force for rotating the electrophotographic photosensitive drum from the main assembly of the electrophotographic image forming apparatus when the process cartridge is mounted to the main assembly of the electrophotographic image forming apparatus; a developing frame supporting a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, a developer frame having a developer accommodating portion for accommodating a developer to be used to develop the electrostatic latent image by the developing roller; a first end cover fixed to one longitudinal end of the drum frame, the developing frame and the developer frame and fixed to the one ends of the drum frame and the developer frame; and a second end cover fixed to the other longitudinal ends of the drum frame, the developing frame and the developer frame and fixed to the other ends of the drum frame and the developer frame, the second end cover including a grip for facilitating mounting and demounting of the process cartridge relative to the main assembly of the electrophotographic image forming apparatus, the method comprising: 
   (a) an end cover removing step of cutting a fixing portion between the second end cover and the drum frame and cutting a fixing portion between the second end cover and the developer frame, and removing the second end cover at the other longitudinal ends of the drum frame, the developing frame and the developer frame; 
   (b) a drum shaft removing step of removing, at the other ends, a drum shaft rotatably supporting the electrophotographic photosensitive drum at the other ends; 
   (c) a roller separating step of applying forced to the drum frame, the developing frame and the developer frame in directions crossing with a longitudinal direction of electrophotographic photosensitive drum so as to separate the electrophotographic photosensitive drum and the developing roller from each other; 
   (d) a drum removing step of moving the electrophotographic photosensitive drum outwardly from the process cartridge at the other end of the electrophotographic photosensitive drum, while keeping the forces applied to the drum frame, the developing frame and the developer frame, so that electrophotographic photosensitive drum is inclined, and then removing the electrophotographic photosensitive drum from the drum frame; 
   (e) a drum mounting step of inserting one end of a new electrophotographic photosensitive drum having at one end a driving force receiving portion for receiving a driving force for rotating the electrophotographic photosensitive drum from the main assembly of the electrophotographic image forming apparatus when the process cartridge is mounted to the main assembly of the electrophotographic image forming apparatus, such that a driving force receiving portion is exposed outside the drum frame, and inserting the drum shaft at the other end from outside of the drum frame, thus mounting a new drum electrophotographic photosensitive drum to the drum frame; 
   (f) a developer refilling step of opening a filling port provided in the developer accommodating portion, refilling the developer and then closing the filling port; and 
   (g) an end cover mounting step of fixedly mounting a second end cover to the other longitudinal ends of the drum frame, the developing frame and the developer frame. 
   These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a vertical sectional view of an electrophotographic image forming apparatus, at a plane perpendicular to the axial line of the electrophotographic photoconductive drum. 
       FIG. 2  is a vertical sectional view of a process cartridge at a plane perpendicular to the lengthwise direction of the axial line of the photoconductive drum. 
       FIG. 3  is an exploded perspective view of the process cartridge. 
       FIG. 4  is a perspective view of the sealing member. 
       FIG. 5  is a perspective view of the sealing member. 
       FIG. 6  is an external plan view of one of the lengthwise ends of the process cartridge, with the end cover removed. 
       FIG. 7  is an external plan view of the other lengthwise end of the process cartridge, with the end cover removed. 
       FIG. 8  is a plan view of the toner seal of the developer holding frame. 
       FIG. 9  is a sectional view of the toner seal. 
       FIG. 10  is a sectional view of the toner storage unit, before welding. 
       FIG. 11  is a sectional view of the toner storage unit, after welding. 
       FIG. 12  is a perspective view of the end cover and corresponding lengthwise ends of the drum holding frame and developer holding frame, at one of the lengthwise ends of the process cartridge, for showing the method for attaching the end cover. 
       FIG. 13  is a perspective view of the end cover and corresponding lengthwise ends of the drum holding frame and developer holding frame, for showing the method for cutting off the end cover. 
       FIG. 14  is a perspective view of one of the lengthwise end of the process cartridge, with the end cover removed. 
       FIG. 15  is a plan view of the process cartridge, as seen from below during its disassembly. 
       FIG. 16  is a plan view of the process cartridge, as seen from the toner storage unit side during its disassembly. 
       FIG. 17  is a vertical sectional view of the cleaning means holding frame, for depicting the U-shaped groove. 
       FIG. 18  is a vertical sectional view of the cleaning means holding frame. 
       FIG. 19  is a plan view of the process cartridge, as seen from below during its assembly. 
       FIG. 20  is a bottom view of the process cartridge in which a drum is assembled with a sheet-like member. 
       FIG. 21  is a perspective drawing for showing the method for reattaching one of the end covers. 
       FIG. 22  is a perspective view of the process cartridge as seen from diagonally below. 
       FIG. 23  is a perspective drawing for showing the method for refilling toner through the toner inlet. 
       FIG. 24  is a plan view of the process cartridge in the second embodiment, as seen from the developer holding frame side during one of the disassembly steps of the process cartridge. 
       FIG. 25  is a plan view of the process cartridge in the second embodiment, as seen from the developer holding frame side during one of the assembly steps of the process cartridge. 
       FIG. 26  is a perspective view of the process cartridge and milling cutter, as seen from diagonally below during the cutting of the process cartridge for removing the photoconductive drum. 
       FIG. 27  is an assembly diagram for showing the method for reattaching one of the end covers, in the third embodiment of the present invention. 
     FIGS.  28 ( a ),  28 ( b ) and  28 ( c ) are sectional views of different spacers, one for one. 
       FIG. 29  is a sectional view of the spacers and their adjacencies, for showing how the spacers are held. 
       FIG. 30  is a perspective view of the process cartridge. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, the preferred embodiments of the present invention will be described with reference to  FIGS. 1-9 . In the following embodiments, the lengthwise direction means a direction which is perpendicular to the recording medium conveyance direction, and is parallel to the surface of the recording medium being conveyed. 
   Embodiment 1 
   Description of Process Cartridge and Image Forming Apparatus Main Assembly 
     FIG. 1  shows the vertical section of a typical electrophotographic image forming apparatus, perpendicular to the lengthwise direction, and  FIG. 2  shows the vertical section of a typical process cartridge, perpendicular to the lengthwise direction. 
   The process cartridge P in this embodiment is structured as shown in FIG.  2 . In other words, the process cartridge P comprises: a drum holding frame  13 , in which a charge roller  12  as a charging means, and a cleaning blade  14  as a cleaning means, are disposed around an electrophotographic photoconductive drum  11 ; a developing means holding frame, as a developing apparatus D, which supports a development roller  18  and development blade  26 ; a toner storage unit in which stirring members  34 ,  35 , and  36  for stirring the toner, and to which a toner storage lid  31  is welded. 
   A drum protection shutter  19  for protecting the photoconductive drum  11  is supported by the drum holding frame  13 . These frame and shutter are integrated into the form of a cartridge P, which can be mount or dismount, into or from, the image forming apparatus main assembly C, without subjecting the processing means to an undue amount of force, by grasping a handle  10  provided on the top surface of the toner storage lid  31 . 
   The shutter  9  takes a closed position at which it completely covers the transfer opening  13   n , or an open position at which it fully exposes the transfer opening  13   n . More specifically, as the cartridge P is moved out of the apparatus main assembly C, it moves from the open position to the closed position, preventing the photoconductive drum  11  from being physically damaged, or from being exposed to external light, and as the cartridge P is mounted into the apparatus main assembly C, it moves from the closed position to the opening position, exposing the transfer opening  13   n , allowing the photoconductive drum  11  to directly oppose a transfer roller  5 . The transfer opening  13   n  is narrow and long, and its dimension in terms of the lengthwise direction of the photoconductive drum  11  exceeds the image formation range in terms of the lengthwise direction of the photoconductive drum  11 . The dimension of the transfer opening  13   n  in terms of the direction perpendicular to the lengthwise direction of the photoconductive drum  11  is greater than the diameter of the photoconductive drum  11 . The transfer opening  13   n  is located between the drum holding frame  13  and developing means holding frame  17 . In terms of the lengthwise direction, the position of one of the edges of the transfer opening  13   n  coincides with the position of the inward surface of the bearing cover portion  13   h  extending downward from the drum holding frame  13 , whereas the position of the other edge coincides with the position of the inward surface of the bearing cover portion  29   a  extending downward from the bottom cover  29  attached to the developer holding frame  30 . The bearing cover portions  13   h  and  29   a  are connected to each other at a joint  44 , forming an arcuate portion, the center of which virtually coincides with the axial line of the photoconductive drum  11 . The peripheral surface of the photoconductive drum  11  is exposed through this transfer opening  13   n.    
   As described above, the positions of the short edges, that is, the edges at the lengthwise ends, of the transfer opening  13   n  coincide with those of the inward surfaces of the bearing cover portions  13   n  and  29   a.    
   The cartridge P is mounted in an image forming apparatus such as the one shown in  FIG. 1 , to be used for image formation. 
   The photoconductive drum  11  is charged by the charge roller  12 , and selectively exposed by an exposing apparatus  8 , in accordance with the image formation data. As a result, an electrostatic latent image is formed. The exposing operation by the exposing apparatus  8  is carried out in synchronism with the conveyance of the sheet S by a registration roller pair  3 . 
   Meanwhile, the toner in the toner storage unit  16  is conveyed to the development means holding frame  17 , in which it is borne in a thin layer on the peripheral surface of the development roller  18  by the development blade  26 . Then, development bias is applied to the development roller  18  so that the toner is supplied to the latent image on the peripheral surface of the photoconductive drum  11 . As a result, a toner image is formed on the peripheral surface of the photoconductive drum  11 . This toner image is transferred onto the aforementioned sheet S, which is being conveyed through the transfer station after having been conveyed thereto by the conveying rollers  7 , by the application of bias voltage to the transfer roller  5 . Then, the sheet S is conveyed to a fixing apparatus  4 , in which the toner image is fixed to the sheet S. Then, the sheet S is discharged into a delivery portion  2  on top of the apparatus main assembly, by sheet discharge rollers  1 . Meanwhile, the residual toner, that is, the developer remaining on the peripheral surface of the photoconductive drum  11 , is removed by the cleaning blade  14 , and is collected into the drum holding frame  13 . 
   Structure of Process Cartridge Frame 
   Next, the developing apparatus and its adjacencies will be described further in detail. 
     FIG. 2 and 3  shows the structure of the cartridge P in this embodiment. The developing apparatus D of the cartridge P places the toner from the toner storage unit  16  onto the peripheral surface of the development roller  18 , and then, supplies the toner on the peripheral surface of the development roller  18  to the peripheral surface of the photoconductive drum  11 , in accordance with the latent image on the peripheral surface of the photoconductive drum  11 , by applying development bias to the development roller  18 . 
   The development roller  18  is cylindrical, and is formed of a metallic material such as aluminum or stainless steel. It contains a magnetic roller  18   a.    
     FIG. 3  is an exploded perspective view of the cartridge P, for showing the components and structure of the cartridge P. The positional relationships between the toner storage unit  16  and end covers  19  and  20  become accurately fixed as the positioning joggles  30   a  protruding from the outward surfaces of the side walls, in terms of the lengthwise direction, of the developer holding frame  30 , into the center holes of the bosses  19   c  and  20   c  of the end covers  19  and  20 , respectively. The drum holding frame  13  rotationally supports the drum  11 , with the interposition of a bearing  41  and a drum shaft  40  located at the lengthwise ends, one for one. The positioning joggle  19   b  and  20   b  are fitted into the center holes of the positioning bosses  13   b , one for one. As a result, the drum holding frame  13  becomes fixed to the end covers  19  and  20  as is the toner storage unit  16 . 
   In other words, the frame  13  and unit  16  are held together by the end covers  19  and  20 . The shaft  40  is provided with a flange portion  40   a , a first shaft portion  40   b , and a second shaft portion  40   c . The flange portion  40   a  is the portion by which the shaft  40  is attached to the frame  13 , and the a first shaft portion  40   b  is the portion to be inserted into the center hole of the flange  11   a  of the drum  11 . The second shaft portion  40   c  perpendicularly protrudes from the outward surface of the flange portion  40   a  (therefore, in the direction opposite to the direction in which the first shaft portion  40   b  protrudes), long enough to project outward through the hole  19   a  of the end cover  19 . The aforementioned flange  11   a  is guided by a U-shaped groove  13   g  (contoured by a dotted line in  FIG. 3 , and contoured by a solid line in  FIG. 17 ) in the inward surface of the frame  13 , when the drum  11  is mounted in the frame  13 . Further, the flange  11   a  has a guide portion  11   a   1  for temporarily keeping the drum  11  accurately positioned relative to the frame  13  until the attachment of the shaft  40 . This guide portion  11   a   1  is cylindrical, and is smaller in diameter than the portion of the flange  11   a , from the outward surface of which it perpendicularly projects. Its axial line coincides with that of the drum  11 . 
   Referring to  FIGS. 2 and 3 , the developing means holding frame  17  of the developing apparatus D supports developing members such as the development roller  18 , development blade  12 , and the like. It is connected to the frame  13 , with the pins inserted in the holes  13   a  ( FIG. 6 ) of the frame  13  and the holes  17   a  of the developing means holding frame  17 , being enabled to pivot about the axial line of the holes  17   d  ( 13   a ). Here, referring to  FIG. 6 , which shows one of the lengthwise ends of the cartridge P, with the end cover  20  removed, a tension coil spring  22  is stretched between the frame  13  and frame  17 , being attached to the spring anchoring portions  13   c  and  17   f  projecting from the frames  13  and  17 , respectively. 
   Next, referring to  FIG. 3 , and  FIG. 7  which shows the lengthwise end of the cartridge opposite to the end shown in  FIG. 6 , a compression coil spring  27  is fitted in a groove  19   e  of the end cover  19 , being compressed so that it presses the development roller bearing  17   e , which is secured to the lengthwise end of the frame  17 , rotationally supporting one of the lengthwise ends of the development roller  18 . With the presence of the force from the spring  22 , a pair of spacer rings  18   b , which are greater in radius by an amount equivalent to the development gap (approximately 300 μm) than the photoconductive drum  11  and are concentrically fitted around the lengthwise end portions of the development roller  18 , are kept pressed upon the peripheral surface of the photoconductive drum  11 , outside the image formation range. With the provision of this structural arrangement, a gap is provided between the developing means holding frame  17  and developer holding frame  13 . 
   In this embodiment, the gap between the developing apparatus D and developer holding frame  30  is sealed with a sealing member in the formed of follows, which is made by folding and pasting a jointing sheet  21  attached to the developer holding frame  30  with the inter position of a jointing plate  23 . The jointing sheet  21  in this embodiment is no more than 1 mm in thickness. However, the jointing sheet thickness may be more than 1 mm, provided that the substance selected as the material for the jointing sheet  21  is such that even if it is made into a jointing sheet thicker than 1 mm, it does not prevent the bellows-like jointing member, into which the jointing sheet is fold, from remaining flexible. 
   Referring to  FIG. 12 , the outwardly edge  13   d  of the drum holding frame  13 , the outward edge  16   a  of the toner storage unit  16 , and inward edge  19   i  of the end cover  19 , are structured so that as the combination of the drum holding frame  13  and toner storage unit  16  is joined with the end cover  19 , a groove (unshown) is formed, into which melted resin is flowed through the gate  19 h of the end cover  19 . As melted resin is flowed into this groove, the frame  13 , unit  16 , and end cover  19  are solidly secure to each other. The, the end cover  20  is also joined with the combination of the frame  13  and unit  16 , in the same manner as is the end cover  19 , completing the cartridge P. 
   The charge roller  12  comprises a metallic core  12   c , and a cylindrical rubber layer ( FIG. 3 ) fitted around the metallic core  12   c . The electrical resistance of the rubber layer is in the mid range. Referring to  FIG. 17 , the frame  13  is provided with a guide-way  13   i , which extends in the lengthwise direction of the frame  13  in parallel to the axial line of the photoconductive drum  11 , astride the axial line of the photoconductive drum  11 , in terms of the direction perpendicular to the lengthwise direction of the photoconductive drum  11 . In this guide-way  13   i , a charge roller bearing  12   a  is slidably fitted. In this bearing  12   a , the metallic core  12   c  of the charge roller  12  is rotationally fitted. At the rear end of the cartridge P, a compression coil spring  12   b  is disposed between the guide-way  13   i  and bearing  12   a . The spring  12   b  is fitted around a projection of the charge roller bearing  12   a , with the anchoring portion of the spring  12   b  tightly fitted around the base portion of the projection, facilitating the process cartridge assembly. With this structural arrangement, the charge roller  12  is kept pressed upon the drum  11 , by the pressure applied to the charge roller  12  by the resiliency of the spring  12   b  through the bearing  12   b . Incidentally, the charge roller  12  is rotated by the rotation of the photoconductive drum  11 . 
   Method for Forming Pouch-like Sealing Member 
   Next, referring to  FIGS. 4 and 5 , a method for forming the pouch-like sealing member from the jointing sheet  21  is roughly described. Referring to  FIG. 4 , the jointing sheet  21  is provided with holes  21   a  and  21   b , the sizes of which are approximately the same as, or greater than, those of the holes  23   b  and  17   b  of the jointing plate  23  and developing means holding frame  17 , respectively. The jointing sheet  21  is attached to the edges of the holes  23   b  and  17   b  of the jointing plate  23  and developing means holding frame  17 , by the edge portions  21   c  and  21   e  of the holes. 
   In this embodiment, the jointing sheet  21  is attached to the developing means holding frame  17  and jointing plate  23  by a thermal welding method, such as a thermal sealing method or an impulse sealing method. However, ultrasonic welding, adhesive, adhesive tape, or the like methods, may be used. 
   After being attached to the developing means holding frame  17  and jointing plate  23 , the jointing sheet  21  is folded in the direction indicated by an arrow mark, as shown in  FIG. 5 , so that the holes  21   a  and  21   b  squarely face each other (holes  23   b  and  17   b  squarely face each other). Then, the two sections of the jointing sheet  21  created by the folding are attached to each other, by the entirety of the edge portion  21   d , creating a bellows-like (pouch-like) member. The means for attaching the above described two sections of the jointing sheet  21  may also be a thermal welding method such as a heat sealing method or an impulse sealing method, a ultrasonic welding, adhesive, adhesive tape, or the like. 
   Next, the jointing plate  23  is attached to the developer holding frame  30 , leaving partially unwelded or unpasted to provide a gap through which a toner seal  24  can be passed. In this embodiment, the portion  23   a  is welded or pasted to the surface  30   h  ( FIG. 10 ) of the frame  30  provided with a hole  32  as a toner delivery hole, except for the area across which the toner seal  24  is kept pressed by a toner sealing member  25  (FIG.  3 ). 
   The provision of the above described structural arrangement, in other words, the placement of the a pouch-like bellows formed of the jointing sheet  21  between the mutually facing surfaces of the frame  30  and frame  17  minimizes the resistance which occurs as the distance between the mutually facing surfaces of the frame  30  and frame  17  varies. Further, the placement of the jointing sheet  21  between the jointing plate  23  and developing means holding frame  17  makes it possible to attach the jointing plate  23  in a manner to cover the toner seal  24 . With the provision of this arrangement, the toner sealing member  25  can be placed in the gap through which the toner seal  24  is passed, preventing toner leak (FIG.  6 ). 
   The provision of the jointing plate  23  makes simpler the configuration of the welding table necessary for welding the jointing sheet  21  to the mutually facing surfaces of the frame  17  and jointing plate  23 , compared to that necessary in the absence of the jointing plate  23 , that is, when the jointing sheet  21  has to be directly pasted to the frame  30 . 
   Further, the provision of the jointing plate  23  makes it possible to assemble the developing means holding frame  17 , jointing plate  23 , and jointing sheet  21  into a unit which can be easily attached to the frame  30 . The frame  17  and unit  16  jointed together into a development unit. 
   Mounting or Dismounting of Process Cartridge into or out of Apparatus Main Assembly 
     FIG. 1  is a sectional view of an image forming apparatus, in which the cartridge P is ready for image formation. In order to dismount the cartridge P in the state shown in  FIG. 2 , a lever (unshown) located on the front wall of the apparatus main assembly C is to be rotated. As the lever is rotated, an arm  28  is rotated in the direction indicated by an arrow mark (a). As a result, the left side of the cartridge P, with reference to the drawing, is raised by a part (unshown) of the arm  28 . As the left side of the cartridge P is raised, the cartridge P rotates, while being raised, about the guide portions  15   b  rested on the guide rails  111  of the apparatus main assembly C, until the guide portions  15   a , with which only the back side of the cartridge P is provided, aligns with the guide rails  110  of the apparatus main assembly C. In this state, the cartridge P is to be pulled toward the front side of the apparatus main assembly C, in the direction perpendicular to the plane of the FIG.  1 . As the cartridge P is pulled, the guide portions  15   a  transfers onto the guide rails  110 , and the cartridge P becomes disengaged from the arm  28 . Then, the cartridge P can be pulled straight out of the apparatus main assembly C. 
   The procedure for mounting the cartridge P into the apparatus main assembly C is reverse to the above described dismounting procedure. In other words, the cartridge is to be inserted into the apparatus main assembly C, with the guide portion  15   a  and fulcrum  15   b  aligned with the rails  110  and  111 , in the direction perpendicular to the plane of the FIG.  1 . As the cartridge is inserted inward of the apparatus main assembly C, the top left portion of the cartridge P is caught by the arm  28  before the guide portion  15   a  becomes disengaged from the rail  110 . Then, as the cartridge P is pushed further into the apparatus main assembly C, the guide portion  15   a  disengages from the rail  110 . Then, a lock (unshown) of the arm  28  is to be disengaged, and the aforementioned lever (unshown) on the front side of the apparatus main assembly C is to be rotated to rotate the arm  28  in the direction opposite to the direction indicated by the arrow mark (a). The rotation of the arm  28  is assisted by the weight of the cartridge P itself. 
   As the cartridge P approaches the position at which the cartridge can form an image, the second shaft portion  40   c  of the drum shaft  40  ( FIG. 3 ) protruding outward of the end cover  19 , through the aforementioned hole  19   a  of the end cover  19 , shown in  FIG. 3 , fits into the drum shaft positioning recess (unshown) of the apparatus main assembly C, being therefore accurately positioned (drum bearing  41  on the end cover  20  side protrudes outward through the hole  20   a  of the end cover  20 ). As a result, the cartridge P is accurately positioned relative to the apparatus main assembly C, and therefore, the photoconductive drum  11  is accurately positioned relative to the apparatus main assembly C, because the axial lines of the photoconductive drum  11 , drum bearing  41 , and drum shaft  40  coincide. 
   The side wall of the end cover  19 , which surrounds the second shaft portion  40   c , makes contact with the inward surface of the portion of apparatus main assembly C with the recess (unshown) in which the shaft portion  40   c  fits. As a result, the position of the cartridge P relative to the apparatus main assembly C in terms of the lengthwise direction is accurately fixed. With the provision of the above described structural arrangement, even a process cartridge (P), which is heavy because of a large amount of toner contained in the developer holding frame  30 , can be smoothly mounted into, or dismounted from, the apparatus main assembly C. Incidentally, the cartridge P is also provided with a handle  19   g  (FIG.  12 ), in addition to the handle  10  on the top surface. The handle  19   g  is attached to the second end cover  19 , being on the front side in terms of the direction in which the cartridge P is mounted or dismounted. The provision of the additional handle  19   g  makes it easier to carry the cartridge P, and also to handle the cartridge P at the beginning of the mounting of the cartridge P or the end of the dismounting of the cartridge P. 
   The flange  11   b  of the drum  11 , on the driven side, comprises a journal portion  11   b   1 , which is rotationally supported by the bearing  41 , and a driving force receiving portion  11   b   2 , which projects from the journal portion  11   b   1 . The driving force receiving portion  11   b   2  is in the form of a triangular pillar which is twisted about its axial line, and has a cross section in the form of an equilateral triangle. It is driven by the driving shaft on the apparatus main assembly C side, being fitted into the twisted triangular hole (unshown) of the driving shaft. 
   Description of Toner Storage Unit 
   Next, referring to  FIGS. 8 ,  9 ,  10 , and  11 , the unit  16  will be described. The unit  16  comprises the frame  30 , toner storage lid  31 , and stirring members  34 ,  35 , and  36 . Referring to  FIG. 8 , the frame  30  is provided with the developer delivery hole  32  through which the toner is sent out to the developing means holding frame  17 . The hole  32  is covered with the seal  24 , which is thermally welded to the unit  16 , along the surrounding edge of the hole  32  (FIG.  8 ). A referential code  50  stands for the welded portion (hatched portion). 
   The toner seal  24  in this embodiment has a laminar structure, having: 
   a 12 μm thick polyester layer (strength providing layer:  24   i  in FIG.  9 ), 
   a 7 μm thick aluminum foil layer (laser beam blocking layer:  24   j  in FIG.  9 ), 
   a 50 μm thick polyester layer (tear guiding layer:  24   k  in FIG.  9 ), and 
   a 50 μm thick sealant layer (adhesive layer:  241  (el) in FIG.  9 ), listing from the top layer. 
   Tear lines  24   e  of the seal  24 , along which the seal  24  is torn open, have been subjected to a laser-cut process for creating gaps in the tear guiding layer, along the tear lines  24   e .  FIG. 9  is a sectional view of the seal  24 . The seal  24  has a gap  24   h  created by a laser. The provision of the aluminum foil layer  24   j  which blocks a laser beam prevents the top polyester layer, or the strength providing layer  24   i , from being damaged by the laser beam, assuring satisfactory sealing performance. The provision of the aluminum foil layer also causes the stress to concentrate to the gap  24   h  when the seal  24  is pulled to be opened, ensuring that the seal  24  is torn along the tear lines  24   e.    
   Referring to  FIG. 10 , within the frame  30 , the stirring members  34 ,  35 , and  36  are provided, which send the toner to the developing means holding frame  17  through the toner delivery hole  32 , while stirring the toner. The stirring members  34 ,  35 , and  36  comprise: shaft  34   c ,  35   c , and  36   c ; stirring blades  34   a ,  35   a , and  36   a ; and blade holders  34   b ,  35   b , and  36   b , by which the stirring blades  34   a ,  35   a , and  36   a , are held to the shafts  34   c ,  35   c , and  36   c , respectively. In this embodiment, the blade  34   a  is formed of 50 μm thick PPS sheet, and blades  35   a  and  36   a  are formed of approximately 100 μm thick PPS sheet. The stirring members  34 ,  35 , and  36  all rotate in the same direction (clockwise in FIG.  2 ). The stirring member  34 , that is, the stirring member nearest to the developing means holding frame  17  rotates at approximately 20 rpm, and the other two stirring members  35  and  36  rotate at approximately 5 rpm. 
   The bottom wall of the frame  30  is shaped so that its cross section looks as if it is made by connecting three semicircles:  30   c ,  30   d , and  30   e , the centers of which coincide with the axial lines of the shafts  34   c ,  35   c , and  36   c , respectively. The distances from the axial lines of the shafts  34   c ,  35   c , and  36   c  to the tips of the blades  34   a ,  35   a , and  36   a , when the blades are straight, are made greater than the radii of the semicircular portions  30   c ,  30   d , and  30   e , respectively, making it possible for the blades  34   a ,  35   a , and  36   a  to stir the toner while scraping the bottom wall of the frame  30 . Therefore, even after the remaining amount of the toner becomes small due to toner delivery, the blades can scrape the toner away from the bottom wall, and send the toner to the developing means holding frame  17 , reducing the amount of the unusable toner, or the toner which fails to be delivered and remains in the developer holding frame  30 . In this embodiment, the distances the blades  34   a ,  35   a , and  36   a  hypothetically invade into the semicircular portions  30   c ,  30   d , and  30   e , respectively, of the bottom wall are 2-4 mm. 
   Within the frame  30 , a bridge-like rib  30   b  is provided, which extends from the internal surface  30   i  of the wall  30   h  to which the aforementioned jointing plate  23  is attached in a manner to cover the hole  32 , to the rear wall  30   k , in terms of the cartridge mounting direction, of the frame  30 . The bottom edge of the rib  30   b  is contoured so that it does not interfere with the installation of the stirring member  34  into the frame  30 , being slanted across the portion  30   j  near the edge of the hole  32 , and being arcuate across the portion  30   m  next to the rear wall  30   k.    
   The lid  31  is provided with isolation ribs  31   a  and  31   b , which extend in the lengthwise direction of the cartridge. In terms of the direction perpendicular to the lengthwise direction of the cartridge, the positions of the isolation ribs  31   a  and  31   b  virtually coincide with the position of the joint  30   f  between the semicircular portions  30   c  and  30   d , and the position of the joint  30   g  between the semicircular portions  30   d  and  30   e , of the bottom wall of the frame  30 . In order for the ribs  31   a  and  31   b  not to interfere with the rib  30   b  within the developer holding frame  30 , the center portions  31   c  of the rib  31   a  and  31   b  have been cut out (FIG.  3 ). After the installation of the stirring members  34 ,  35 , and  36  into the frame  30 , the lid  31  and frame  30  are welded to each other by ultrasonic welding or vibration welding, completing the toner storage unit  16 . The gaps  37  and  38  left between the ribs  31   a  and  31   b  and the protruding joints  30   f  and  30   g  are the gaps necessary for sending out the toner. In this embodiment, the gaps are approximately 10 mm-30 mm wide. 
   After assembling the unit  16  as described above, the frame  30  is filled with the toner through the toner inlet  30   l  (el), and is sealed with a toner cap  39 , completing the unit  16 . 
   The inlet  30   l  (el) is provided as a filling opening at one of the lengthwise ends of the frame  30 . 
   Embodiment 1 of Process Cartridge Remamufacturing Method in Accordance with Present Invention 
   Next, a method for overhauling the cartridge P in this embodiment will be described. 
   First, referring to  FIG. 22 , the shafts  9   a  and  9   b  of the shutter  9  fitted in the holes  19   h  and  20   h  of the end covers  19  and  20  are removed from the end covers  19  and  20  by being bent in the direction indicated by an arrow mark D, against their resiliency. Incidentally, the shafts  9   a  and  9   b  are integral parts of a member engaged with the shutter  9 . The shafts  9   a  and  9   b  are formed of spring steel. 
   Next, the cartridge P is secured to a chuck (unshown) of a milling machine. Then, a milling cutter  60  is positioned in a manner to cut into the welded portions  19   i  of the seam between the inward edge of the end cover  19  and outward edge of the drum holding frame  13 , or the seam between the inward edge of the end cover  19  and outward edge of the frame  30 , and is moved along the inward edge of the end cover  19 , cutting through the welded portions  19   i . The milling cutter  60  is a metal circular saw having teeth suitable for cutting through synthetic resin. As a result, the end cover  19  is released from the cartridge P. In this embodiment, a milling cutter is used for cutting, but a ultrasonic cutter, a heated blade, a rotating blade other than a milling cutter, or the like, may be used as the tool for disassembly. As for the choice of the milling machine for cutting the welded portion  19   i , an NC milling machine is most suitable. 
   Thereafter, the small screws  61  holding the drum shaft  40  to the drum holding frame  30  are removed to disengage the drum shaft  40  from the frame  30 , as show in FIG.  14 . Incidentally, the drum shaft  40  is interposed between the photoconductive drum  11  and drum holding frame  30  to rotationally support the photoconductive drum  11  by the drum holding frame  30 . Next, referring to  FIG. 15 , the guide portion  11   al  of the flange  11   a  having a gear is moved sideways following the U-shaped groove  13   g  ( FIG. 17 ) of the drum holding frame  13 , and is disengaged from the groove  13   g , while forcefully keeping widened the gap between the frame  13  and development unit  42 , on the end cover  19  side. Then, the photoconductive drum  11  is removed from the drum holding frame  13 , in the diagonally upward direction indicated by an arrow mark G in  FIG. 16 , through the transfer opening  13   n , while the gap between the drum holding frame  13  and development unit  42  is still kept forcefully widened. During this procedure, the components fixed to the end covers  19  and  20  are distorted. However, there will be no problem, because the extent of their distortion remains within a reversible distortion range afforded by the elasticity of their material. 
   After the photoconductive drum  11  is removed from the cartridge P, the cleaning blade  14  attached to the inward side of the drum holding frame  13  is examined for damages. With the presence of damages, first, the charge roller  12  is removed through the transfer opening  13   n , and the cleaning blade  14  is removed by removing the small screws  62  holding the cleaning blade  14 . When the toner which was removed from the photoconductive drum  11  and collected into the drum holding frame  13  remains by a substantial amount in the drum frame  13 , the toner is removed. Then, the removed blade  14  is reattached to the inward side of the frame  13 , with the use of the small screws  62 , provided that the blade  14  was not damaged. When the removed blade  14  was damaged, a new one is attached. For the removal of the transfer residual toner within the frame  13 , a nozzle is inserted into the frame  13  through the transfer opening  13 n, and the toner is vacuumed out through the nozzle. Another nozzle may be inserted into the frame  13  to blow air into the frame  13  to blow out the toner. 
   Next, the insertion of the drum will be described. When the removed photoconductive drum  11  is not damaged, being thereby recyclable, it is reused. On the other hand, when it is damaged, or had reached the end of its service life, a new one is used. Here, the insertion of the photoconductive drum  11  is described with reference to a new one. Referring to  FIG. 19 , the gap between the frame  13  and unit  42  is forcefully widened, and kept widened, as was when the photoconductive drum  11  was removed from the development unit  42 . Then, a new photoconductive drum  11 ′ is inserted. More specifically, the end portion of the flange  11 ′ b  with a gear, of the new drum  11 ′ is inserted into the bearing  41 , within the end cover  20 , diagonally from above, through the gap, and then, the guiding portion  11 ′ al  of the flange  11 ′ a  is inserted sideways into the U-shaped groove  13   g . During this procedure, the new photoconductive drum  11 ′ is protected by a sheet  63 , as shown in  FIG. 20 , to prevent the new photoconductive drum  11 ′ from being damaged by the corners of the drum holding frame  30  and developing means holding frame  17 . The sheet  63  may be removed thereafter. The magnet pasting portion  13   f  protruding from the end portion of the frame  13 , to which a magnet  65  ( FIG. 18 ) for capturing the scattered toner particles is pasted, may be eliminated to prevent the magnetic pasting portion  13   f  from coming into contact with the photoconductive drum  11 ′. The pasting portion  13   f  protrudes from the lengthwise end of the transfer opening  13   n , in the direction perpendicular to the lengthwise direction. The elimination of the pasting portion  13   f  may be carried out as the first step in the process cartridge remanufacturing process. Then, the drum shaft  40  is attached following in reverse the steps followed to remove it (FIG.  14 ), rotationally attaching the photoconductive drum  11 ′ to the frame  13 . 
   Next, referring to  FIG. 23 , the refilling of the toner will be described. First, a toner cap  39  attached to the toner inlet  30   l  (el) of the unit  16  is removed. Then, a funnel  67  is inserted into the inlet  30   l  (el), and the toner is filled into the unit  16  by a necessary amount. After the refilling of the toner, the toner inlet  30   l  is recapped with the same cap  39 , provided that the same toner cap  39  is reusable. When it is damaged, or has become defective for some reason, it is replaced with a new cap, which is inserted into the inlet  30   l . If the toner adheres to the adjacencies of the toner inlet  30   l , or the other places, it is to be removed after the refilling of the unit  16  with the toner. Next, the end cover  19  is attached to the combination of the frame  13  and unit  42  in the direction indicated by an arrow mark in FIG.  21 . For the adjustment of the dimension of the end cover  19  in terms of the lengthwise direction of the cartridge P, a spacer  64  having a thickness equal to that of the portion removed by the milling cutter  60  is interposed between the end cover  19  and the combination of the frame  13  and unit  42  so that the spacer  64  fits around the outward facing edge E and inwardly facing edge H of the combination of the frame  13  and unit  42 , and the end cover  19 , respectively, and that the dimension of the cartridge P in terms of its lengthwise direction is adjusted. As for the methods for securing the end cover  19 , there are a method in which double-side adhesive tape is pasted to both surfaces of the spacer  64 , a method in which the end cover  19  and the combination of the frame  13  and development unit are held together with the use of clips which lock onto the recesses of the end cover  19  and the combination of the frame  13  and unit  42 , or the like methods. After the attachment of the end cover  19 , the removed shutter  9  is reattached following in reverse the steps followed to detach it. 
   With the employment of a remanufacturing method such as the one described above, a process cartridge, the service life of which has expired, can be reused. 
   Embodiment 2 of Process Cartridge Remanufacturing Method in Accordance with Present Invention 
   Next, the second embodiment of the process cartridge overhauling method in accordance with the present invention will be described. 
   Referring to  FIG. 22 , the shafts  9   a  and  9   b  of the shutter  9  fitted in the holes  19   h  and  20   h  of the end covers  19  and  20  (end cover  19  side is unshown) are removed from the end covers  19  and  20  by being bent in the direction indicated by an arrow mark D. Then, the shutter  9  is disengaged from the cartridge P (up to this point, procedure is the same as that in Embodiment 1). 
   Next, referring to  FIG. 26 , the cartridge P is secured to the chuck (unshown) of a milling machine. Then, a milling cutter  60  is placed in contact with the peripheral surface of the photoconductive drum  11 , and the drum  11  is rotated by rotating the driving force receiving portion  11   b   2 , that is, the end portion of the flange  11   b , so that the drum  11  is cut along the dotted lines  11   c  and  11   d . Next, the portion  11   e  of the drum  11  between the two dotted cutting lines  11   c  and  11   d  is extracted through the transfer opening  13   n . Then, the remaining two pieces of the drum portions are extracted from the transfer opening  13   n , in the direction indicated by an arrow mark G (diagonally upward in the drawing). More specifically, the center sides of the remaining two drum pieces are raised, tilting thereby the two drum pieces, at an angle within a range which can be afforded by the gap between the bearings  41  and flanges  11   a  and  11   b , and within the reversible deformation range which can be afforded by the elasticity of the components around the bearings  41 . Then, the two drum pieces are pulled out of the drum holding frame  13  through the transfer opening  13 n. 
   Next, referring to  FIG. 13 , the milling cutter  60  is positioned in a manner to cut into the joint  19   i  (portion indicated by dotted line in the drawing), and is moved along the inward edge of the end cover  19 , cutting through the welded portions  19   i . As a result, the end cover  19  is detached from the cartridge (cutting of the joint  19   i  is the same as that in Embodiment 1, and therefore, Embodiment 1 should be referred to for the details of the cutting of the joint  19   i  in this embodiment). 
   Thereafter, the small screws  61  holding the drum shaft  40  are removed as shown in  FIG. 17 , and the shaft  40  is removed from the frame  13 . 
   Next, referring to  FIG. 18 , the cleaning blade  14  attached to the inward side of the frame  13  is examined for damages. With the presence of damages, first, charge roller  12  is removed through the transfer opening  13   n , and the cleaning blade  14  is removed by removing the small screws  62  holding the cleaning blade  14 . When the toner which was removed from the photoconductive drum  11  and collected into the drum holding frame  13  remains by a substantial amount in the drum frame  13 , the toner is removed. Then, the removed blade  14  is reattached to the frame  13 , with the use of the small screws  62 , provided that the blade  14  was not damaged. When the removed blade  14  was damaged, a new one is attached (the same procedure as that in Embodiment 1). 
   Next, the insertion of the drum will be described with reference to  FIGS. 19 and 25 . First, referring to  FIG. 25 , the end portion of the flange  11 ′ c  with a gear, of a new photoconductive drum  11 ′ is inserted into the bearing  41 , diagonally from above (direction indicated by an arrow mark H). Incidentally, the bearing  41  is within the end cover  20 . Then, the gap between the drum frame  13  and development unit  42 , on the side from which the second end cover  19  has been removed, is widened by pressing the frame  13  and unit  42  in the directions indicated by arrow marks F, as shown in FIG.  19 . Then, the guiding portion  11 ′ al  of the flange  11 ′ a  is moved following the U-shaped groove  13   g  ( FIG. 17 ) of the drum frame  13 , and is inserted sideways into the U-shaped groove  13   g . During this procedure, the new photoconductive drum  11 ′ is protected by a sheet  63 , as shown in  FIG. 20 , to prevent the new photoconductive drum  11 ′ from being damaged by the corners of the drum holding frame  30  and developing means holding frame  17 . The sheet  63  may be removed thereafter. Next, the magnet pasting portion  13   f  is eliminated as described before, to prevent the magnetic pasting portion  13   f  from coming into contact with the photoconductive drum  11 ′. Then, the drum shaft  40  is attached following the in reverse the steps followed to remove it (FIG.  14 ), rotationally attaching the photoconductive drum  11 ′ to the frame  13  (the same procedure as that in Embodiment 1). Incidentally, the flange  11 ′ a  is at the lengthwise end of the drum  11  on the cover  19  side. 
   Next, referring to  FIG. 23 , the refilling of the toner will be described. First, a toner cap  39  attached to the toner inlet  30   l  (el) of the unit  16  is removed. Then, a funnel  67  is inserted into the inlet  30   l  (el), and the toner is filled into the unit  16  by a necessary amount. After the refilling of the toner, the toner inlet  301  is recapped with the same cap  39 , provided that the same toner cap  39  is reusable. When it is damaged, or has become defective for some reason, it is replaced with a new cap, which is inserted into the inlet  30   l . If the toner adheres to the adjacencies of the toner  30   l , or the other places, it is to be removed after the refilling of the unit  16  with the toner. Next, the end cover  19  is attached to the combination of the frame  13  and unit  42  in the direction indicated by an arrow mark in FIG.  21 . For the adjustment of the dimension of the end cover  19  in terms of the lengthwise direction of the cartridge P, a spacer  64  having a thickness equal to that of the portion removed by the blade of the milling cutter  60  is interposed between the end cover  19  and the combination of the frame  13  and unit  42  so that the spacer  64  fits around the outward facing edge E and inwardly facing edge H of the combination of the frame  13  and unit  42 , and the end cover  19 , respectively, and that the dimension of the process cartridge P in terms of its lengthwise direction is adjusted. As for the methods for securing the end cover  19 , there are a method in which double-side adhesive tape is pasted to both surfaces of the spacer  64 , a method in which the end cover  19  and the combination of the frame  13  and development unit are held together with the use of clips, or the like methods. After the attachment of the end cover  19 , the removed shutter  9  is reattached following in reverse the steps followed to remove it (the same procedure as that in Embodiment 1). 
   The second embodiment is different from the first embodiment only in a few steps. With the employment of a remanufacturing method such as those described above, a process cartridge, the service life of which has expired, can be reused. 
   Embodiment 3 of Process Cartridge Remanufacturing Method in Accordance with the Present Invention 
   The reassembling of the cartridge P, which has been disassembled as described above, will be described in detail, regarding the end covers, with reference to  FIGS. 27 and 30 . Here, essentially, the relationship between the end cover  19  and drum holding frame  13  will be described. The procedure for cutting off the end cover  19  is the same as that in the preceding embodiments. The procedure thereafter will be as follows. 
   The first step is to prepare the end cover  19 , frame  13 , and frame  30 , which have been separated from each other. 
   The second step is to prepare an H-shaped spacer  64   a , the effective thickness B of which is the same as the width A of the portion  70 , in terms of the lengthwise direction of the cartridge, eliminated during the disassembly, or virtually the same as the effective thickness of the spacer  64  as a positioning member (A≈B). The width A by which the joint portion of the cartridge is eliminated during the disassembly is determined by the thickness T of the cutting edge of the tool used as a cutting means (T≈A). 
   Adhesive  104 , hot melt, double-sided adhesive tape, or the like, is placed on the surfaces  64   a -1 and  64   a -2 of the spacer  64 , the distance between which determines the effective thickness B of the spacer  64   a . This process may be carried out in advance. 
   The third step is to sandwich the spacer  64   a  with the end cover  19 , the frame  13 , the frame  30 , which have been separated from each other, so that inwardly facing edge  19   d  of the end cover  19  comes into contact with the surface  64   a -1 of the spacer  64   a , and that the outwardly facing edge  13   z  of the frame  13  and the outwardly facing edge  30   n  of the frame  30  come into contact with the surface  64   a -2 of the spacer  64   a . As for the shape of the cross section of the spacer, an H-shape ( 64   a ) in FIG.  28 ( a ), a T-shape ( 64   b ) in FIG.  28 ( b ), and an I-shape ( 64   c ) in FIG.  28 ( c ), are conceivable. The configuration of the spacer  64  may be such that the spacer  64  makes full contact with the entireties of the inward edges  19   d  and  20   m  of the end covers  19  and  20 , respectively, created by the milling, and the entireties of the outward edges of the frame  13  and developer holding frame  30 , respectively, created by the milling, or makes partial contact with them. 
   In the fourth step, jigs  102   a  and  102   b  are attached to the end cover  19 , frame  13 , and frame  30 . More specifically, one end of one of the jigs  102   a  is inserted in the recess  141   a  ( FIG. 30 ) of the end cover  19 , and the other end of the same jig  102   a  is inserted in the recess  141   d  of the frame  13 , whereas one end of the other jig  102   b  is inserted in the recess  141   c  of the end cover  19 , and the other end of the same jig  102   b  is inserted in the recess  141   b  of the frame  30 . After the insertion, the jigs  102   a  and  102   b  are held therein until the adhesive or the like between the joining surfaces dries or solidifies. Referring to  FIG. 29 , instead of the jigs  102   a  and  102   b , an elastic member  103  may be used to keep the end covers  19  and  20  pressed against the drum holding frame  13  and frame  30  placed between the two end covers  19  and  20 , until the adhesive or the like between the joining surfaces dries or solidifies.  FIG. 29  shows the case in which the end cover  20  has also been detached from the frames  13  and  30  by cutting. In the first and second embodiments, there is no spacer on the end cover  20  side. 
   According to this embodiment, the cartridge can be reassembled as accurately as the original cartridge. Further, a larger number of components can be recycled, contributing to the efficient of usage of natural resources, and the environmental protection. 
   Those processes in the process cartridge remanufacturing methods in accordance with the present invention may be changed in order as necessary. 
   The above described embodiments of the present invention include a process cartridge remanufacturing method which involves simultaneously a substantial number of process cartridges with an expired service life, as well as a process cartridge remanufacturing method which involves a single process cartridge with an expired service life. In the case of the former, a substantial number of expired cartridges are recovered, and disassembled. Then, the components removed from the disassembled cartridges are sorted into groups of the identical components. Then, as large as possible a number of cartridges are reassembled from the groups of sorted recyclable components, and some new replacement components for the nonrecyclable old components. In the case of the latter, the expired cartridges are remanufactured one by one. In other words, each time an expired cartridge is recovered, it is disassembled, and reassembled using the same old components removed therefrom, some new replacement components for the nonrecyclable old components, or some old recyclable components removed from the other recovered cartridges. 
   The present invention includes any of the following cases: 
   (1) each expired cartridge is overhauled using only the components therein; 
   (2) each expired cartridge is overhauled using, in principle, the components therein, with the exception of the new replacement components, or the recyclable old components from the other expired cartridge, which replace the original components nonrecyclable due to service life expiration, damages, malfunctions, or the like; 
   (3) a plurality of expired cartridges are overhauled together; the components removed from the plurality of expired cartridges are sorted into groups of the identical components, and as large as possible a number of cartridges are reassembled using only the components from the groups of the original components; and 
   (4) a plurality of expired cartridges are overhauled together; the components removed from the plurality of expired cartridges are sorted into groups of the identical components, and as large as possible a number of cartridges are reassembled using, in principle, the components from the groups of the original components, except for a certain number of new replacement components which replace the original components nonrecyclable due to service life expiration, damages, malfunctions, or the like. 
   The aforementioned components means the structural components disclosed in the claim portion of this specification, that is, the components which make up the above described portions of the cartridge. It also includes the smallest components or units, into which the cartridge can be disassembled. 
   As described above, the present invention is a realization of a simple method for remanufacturing a process cartridge. 
   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 purposes of the improvements or the scope of the following claims.