Patent Publication Number: US-11392079-B2

Title: Process cartridge and image forming apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a process cartridge detachably mountable to an image forming apparatus and an image forming apparatus including the process cartridge. The image forming apparatus forms an image on a recording material using an image forming process. Examples of the image forming apparatus include a printer, a copying machine, a facsimile machine, or word processor and a multi-function machine of these machines. 
     BACKGROUND ART 
     Conventionally, in an image forming apparatus using an electrophotographic image forming process, a photosensitive drum and process parts actable on the photosensitive drum are unfixed into a cartridge. Further, a process cartridge type in which this cartridge is detachably mountable to an apparatus main assembly of the image forming apparatus is employed. 
     According to this process cartridge type, maintenance of the image forming apparatus can be performed by a user himself (herself). As a result, an operationality can be improved remarkably and the process cartridge type is widely used in image forming apparatuses. 
     Japanese Patent No. 4464435 discloses a color electrophotographic image forming apparatus in which a plurality of process cartridges are arranged in a line. Here, in the process cartridge, a drum unit including the photosensitive drum and a developing unit including a developing roller are connected rotatably by a swing center. Further, the photosensitive drum is provided with a drum coupling in one end side with respect to an axial direction of the photosensitive drum. Further, when the process cartridge is mounted in the apparatus main assembly, the drum coupling engages with a main assembly(-side) coupling provided in the apparatus main assembly, so that a first driving force is transmitted. 
     Further, the developing roller is provided with an Oldham coupling which is a shaft coupling member in one end side with respect to an axial direction of the developing roller. The Oldham coupling engages with a main assembly(-side) drive transmitting member, and is constituted by a driving-side engaging portion provided movably in a direction crossing an axis of the developing roller, a follower-side engaging portion fixed to the developing roller, and an intermediary engaging portion provided between the follower-side engaging portion and the follower-side engaging portion. Further, when the process cartridge is mounted in the apparatus main assembly, the driving-side engaging portion engages with a main assembly(-side) developing (means) coupling provided in the apparatus main assembly, so that a second driving force is transmitted. That is, drive transmission from the apparatus main assembly to the process cartridge is performed at independent two positions. 
     In the process cartridge as described above, independent drive transmission is performed on an axis of the photosensitive drum and an axis of the developing roller. In this way, in the case where the cartridge of the photosensitive drum and the coupling of the developing roller are in a relationship in which these couplings are adjacent to each other, an interval between the drive transmitting member for the photosensitive drum and the drive transmitting member for the developing roller narrows. As a result, a degree of flexibility in constitution of the apparatus main assembly or the process cartridge narrows. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention is to provide a process cartridge and an image forming apparatus which are capable of broadening an interval between drive input to a photosensitive drum and drive input to a developing roller. 
     According to the present invention, there is provided a process cartridge comprising: a photosensitive drum; a rotatable developing roller for developing an electrostatic latent image formed on the photosensitive drum; a rotatable roller having a rotation shaft in a position deviated from an axis of the developing roller, for transmitting a driving force to the developing roller; a coupling member disposed at an end portion of the shaft of the rotatable roller; a driving force receiving portion, provided on the coupling member and movable in a direction crossing the shaft of the rotatable roller, for receiving a driving force to be transmitted to the developing roller; an urging member for urging the drive receiving portion in the direction crossing the shaft of the rotatable roller; a supporting portion for rotatably supporting the drive receiving portion so as to be movable together with the drive receiving portion toward the rotatable roller in the direction crossing the shaft of the rotatable roller; and an abutting portion for receiving the supporting portion urged by the urging member, wherein the abutting portion is positioned outside an outer periphery of the photosensitive drum on a plane perpendicular to the shaft of the rotatable roller. 
     Further, according to the present invention, there is provided a process cartridge comprising: a photosensitive drum; a rotatable developing roller for developing an electrostatic latent image formed on the photosensitive drum; a rotatable roller having a rotation shaft in a position deviated from an axis of the developing roller, for transmitting a driving force to the developing roller; a coupling member disposed at an end portion of the shaft of the rotatable roller; a driving force receiving portion, provided on the coupling member and movable in a direction crossing the shaft of the rotatable roller, for receiving a driving force to be transmitted to the developing roller; an urging member for urging the drive receiving portion in the direction crossing the shaft of the rotatable roller; a supporting portion for rotatably supporting the drive receiving portion so as to be movable together with the drive receiving portion toward the rotatable roller in the direction crossing the shaft of the rotatable roller; and an abutting portion for receiving the supporting portion urged by the urging member, wherein the abutting portion is provided so that a point of contact between the abutting portion and the supporting portion is positioned outside an outer peripheral surface of the photosensitive drum on a plane perpendicular to the shaft of the rotatable roller. 
     Further, according to the present invention, there is provided an image forming apparatus comprising: an image forming apparatus main assembly including a driving member for providing a driving force; and a process cartridge detachably mountable to the image forming apparatus main assembly, wherein the process cartridge includes: a photosensitive drum; a rotatable developing roller for developing an electrostatic latent image formed on the photosensitive drum; a rotatable roller having a rotation shaft in a position deviated from an axis of the developing roller, for transmitting a driving force to the developing roller; a coupling member disposed at an end portion of the shaft of the rotatable roller; a driving force receiving portion, provided on the coupling member and movable in a direction crossing the shaft of the rotatable roller, for receiving a driving force to be transmitted to the developing roller; an urging member for urging the drive receiving portion in the direction crossing the shaft of the rotatable roller; a supporting portion for rotatably supporting the drive receiving portion so as to be movable together with the drive receiving portion toward the rotatable roller in the direction crossing the shaft of the rotatable roller; and an abutting portion for receiving the supporting portion urged by the urging member, wherein the abutting portion is positioned outside an outer periphery of the photosensitive drum on a plane perpendicular to the shaft of the rotatable roller. 
     Further, according to the present invention, there is provided an image forming apparatus comprising: an image forming apparatus main assembly including a driving member for providing a driving force; and a process cartridge detachably mountable to the image forming apparatus main assembly, wherein the process cartridge includes: a photosensitive drum; a rotatable developing roller for developing an electrostatic latent image formed on the photosensitive drum; a rotatable roller having a rotation shaft in a position deviated from an axis of the developing roller, for transmitting a driving force to the developing roller; a coupling member disposed at an end portion of the shaft of the rotatable roller; a driving force receiving portion, provided on the coupling and movable in a direction crossing the shaft of the rotatable roller, for receiving the driving force to be transmitted to the developing roller; an urging member for urging the driving force receiving portion in the direction crossing the shaft of the rotatable roller; a supporting portion for rotatably supporting the driving force receiving portion so as to be movable together with the driving force receiving portion toward the rotatable roller in the direction crossing the shaft of the rotatable roller; and an abutting portion for receiving the supporting portion urged by the urging member, wherein the abutting portion is provided so that a point of contact between the abutting portion and the supporting portion is positioned outside an outer peripheral surface of the photosensitive drum on a plane perpendicular to the shaft of the rotatable roller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  includes a side view and a sectional view for illustrating an operation of shaft coupling members when a developing unit is in a contact state and a driving-side engaging portion and a main assembly developing coupling engage with each other in an embodiment of the present invention. 
         FIG. 2  is a principal sectional view of an image forming apparatus in the embodiment of the present invention. 
         FIG. 3  is a principal sectional view of a process cartridge in the embodiment of the present invention. 
         FIG. 4  is a general perspective view of the process cartridge in the embodiment of the present invention. 
         FIG. 5  is a general perspective view of the developing unit in the embodiment of the present invention. 
         FIG. 6  is a schematic view of mounting of a process cartridge in the image forming apparatus in the embodiment of the present invention. 
         FIG. 7  includes are schematic views for illustrating an operation of mounting the process cartridge in an image forming apparatus main assembly in the embodiment of the present invention. 
         FIG. 8  is a perspective view showing a state in which the process cartridge is positioned to the image forming apparatus main assembly in the embodiment of the present invention. 
         FIG. 9  is a sectional view for illustrating a spacing operation of the developing unit in the embodiment of the present invention. 
         FIG. 10  is a sectional view for illustrating a contact operation of the developing unit in the embodiment of the present invention. 
         FIG. 11  is a perspective view before the process cartridge is mounted in the image forming apparatus main assembly in the embodiment of the present invention. 
         FIG. 12  is a perspective view of mounting of the process cartridge in the image forming apparatus main assembly in the embodiment of the present invention. 
         FIG. 13  includes schematic views in which an operation of mounting the process cartridge in the image forming apparatus main assembly is viewed from an apparatus main assembly front side in the embodiment of the present invention. 
         FIG. 14  includes schematic views in which the position of mounting the process cartridge in the image forming apparatus main assembly is viewed from an apparatus main assembly side surface side in the embodiment of the present invention. 
         FIG. 15  is a perspective view for illustrating a supporting constitution for a developer supplying roller and a developing roller in the embodiment of the present invention. 
         FIG. 16  is an exploded illustration of a shaft coupling member in the embodiment of the present invention. 
         FIG. 17  includes sectional illustrations of the shaft coupling member in the embodiment of the present invention. 
         FIG. 18  is a perspective view for illustrating the shaft coupling member in a developing unit state and a first main assembly driving member and a second main assembly driving member of the image forming apparatus main assembly in the embodiment of the present invention. 
         FIG. 19  includes a side view and a sectional view for illustrating an operation of shaft coupling members when the developing unit is in a spaced state and a driving-side engaging portion and a main assembly developing coupling do not engage with each other in an embodiment of the present invention. 
         FIG. 20  includes a side view and a sectional view for illustrating an operation of shaft coupling members when the developing unit is in the spaced state and a driving-side engaging portion and a main assembly developing coupling engage with each other in an embodiment of the present invention. 
         FIG. 21  includes a side view and a sectional view for illustrating an operation of shaft coupling members when a developing unit is in a contact state and a driving-side engaging portion and a main assembly developing coupling engage with each other a conventional example. 
         FIG. 22  includes a side view and a sectional view for illustrating a positional relationship of a drive inputting portion in the case where an abutting portion is provided outside an outer peripheral surface of a photosensitive drum and is provided outside an outer peripheral surface of the developer supplying roller in another embodiment of the present invention. 
         FIG. 23  includes a side view and a sectional view for illustrating a positional relationship of the drive inputting portion in the case where the abutting portion is provided outside the outer peripheral surface of a photosensitive drum and is provided inside the outer peripheral surface of the developer supplying roller in another embodiment of the present invention. 
         FIG. 24  is a perspective view for illustrating a shaft coupling member and a flexible sheet for removing chips in an embodiment of the present invention. 
         FIG. 25  is a side view of a shaft coupling member and a flexible sheet for removing chips in an embodiment of the present invention. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE PRESENT INVENTION 
     First Embodiment 
     In the following, an electrophotographic image forming apparatus according to First Embodiment of the present invention and a process cartridge used therein will be described in accordance with the drawings. 
     (General Structure of Image Forming Apparatus) 
     First, a general structure of an electrophotographic image forming apparatus (hereinafter referred to as an “image forming apparatus”)  100  will be described using  FIG. 2 . As shown in  FIG. 2 , detachably mountable four process cartridges  70  ( 70 Y,  70 M,  70 C,  70 K) are mounted. Further, in this embodiment, an upstream-side side of the process cartridge  70  with respect to a mounting direction to the image forming apparatus  100  is defined as a front (surface) side, and a downstream-side side of the process cartridge  70  with respect to the mounting direction is defined as a rear (surface) side. In  FIG. 2 , the respective process cartridges  70  are inclined and juxtaposed in an apparatus main assembly  100 A with respect to a horizontal direction ht. 
     The process cartridge  70  includes electrophotographic photosensitive drums (hereinafter referred to as “photosensitive drums”)  1  ( 1   a ,  1   b ,  1   c ,  1   d ), and at a periphery of the photosensitive drums  1 , process means such as charging rollers  2  ( 2   a ,  2   b ,  2   c ,  2   d ), developing rollers  25  ( 25   a ,  25   b ,  25   c ,  25   d ), and cleaning members  6  ( 6   a ,  6   b ,  6   c ,  6   d ) are integrally provided. 
     The charging roller  2  electrically charges the surface of the photosensitive drum  1  uniformly, and the developing roller  25  develops a latent image, formed on the photosensitive drum  1 , with a toner to visualize the latent image. The cleaning member  6  removes the toner remaining on the photosensitive drum  1  after a toner image formed on the photosensitive drum  1  is transferred onto a recording material. 
     Further, below the process cartridges  70 , a scanner unit  3  for forming the latent image on the photosensitive drums  1  by subjecting the photosensitive drums  1  to selective exposure to light on the basis of image information is provided. At a lower portion of the apparatus main assembly  100 A, a cassette  99  in which sheets of the recording material S are accommodated is mounted. Further, a recording material feeding portion is provided so that the recording material S can be fed to an upper portion of the apparatus main assembly  100 A by being passed through a secondary transfer roller  69  and a fixing portion  74 . That is, a feeding roller  54  for separating and feeding the sheets of the recording material S in the cassette  99  in a one-by-one manner, a feeding roller pair  76  for feeding the fed recording material S, and a registration roller pair  55  for synchronizing the latent image formed on the photosensitive drum  1  with the recording material S are provided. 
     Further, above the process cartridges  70  ( 70 Y,  70 M,  70 C,  70 K), an intermediary transfer unit  5  as an intermediary transfer means onto which the toner image formed on each of the photosensitive drums  1  ( 1   a ,  1   b ,  1   c ,  1   d ) is to be transferred is provided. The intermediary transfer unit  5  includes a driving roller  56 , a follower roller  57 , primary transfer rollers  58  ( 58   a ,  58   b ,  58   c ,  58   d ) at positions opposing the photosensitive drums  1  for the respective colors, and an opposite roller  59  at a position opposing the secondary transfer roller  69  are provided. Around these rollers, a transfer belt  9  is extended and stretched. 
     Further, the transfer belt  9  is circulated and moved so as to oppose and be contacted to all of the photosensitive drums  1 . Then, the toner images are primary-transferred from the photosensitive drums  1  onto the transfer belt  9  by applying a voltage to the primary transfer rollers  58  ( 58   a ,  58   b ,  58   c ,  58   d ). Then, by voltage application to the secondary transfer roller  69  and the opposite roller  59  disposed inside the transfer belt  9 , the toner images are transferred from the transfer belt  9  onto the recording material S. 
     During image formation, while rotating each of the photosensitive drums  1 , the photosensitive drum  1  uniformly charged by the charging roller  2  is subjected to selective exposure to light emitted from the scanner unit  3 . By this, an electrostatic latent image is formed on the photosensitive drum  1 . The latent image is developed by the developing roller  25 . By this, the toner images of the respective colors are formed on the photosensitive drums  1 , respectively. In synchronism with this image formation, the registration roller pair  55  feeds the recording material S to a secondary transfer position where the secondary transfer roller  69  opposing the opposite roller  59  is contacted to the transfer belt  9 . 
     Then, by applying a transfer bias voltage to the secondary transfer roller  69 , the respective color toner images are secondary-transferred from the transfer belt  9  onto the recording material S. By this, a color image is formed on the recording material S. The recording material S on which the color image is formed is heated and pressed by the fixing portion  74 , so that the toner images are fixed on the recording material S. Thereafter, the recording material S is discharged onto a discharge portion  75  by a (sheet-)discharging roller pair  72 . The fixing portion  75  is disposed at an upper portion of the apparatus main assembly  100 A. 
     (Process Cartridge) 
     Next, the process cartridge  70  in this embodiment will be described with reference to  FIGS. 3 to 5 . 
       FIG. 3  is a principal sectional view of the process cartridge  70  in which the toner is accommodated. Incidentally, the process cartridge  7 Y accommodating the toner of yellow, the process cartridge  7 M accommodating the toner of magenta, the process cartridge  7 C accommodating the toner of cyan, and the process cartridge  7 K accommodating the toner of black have the same cartridge constitution. 
     The respective process cartridges  70  include drum units  26  ( 26   a ,  26   b ,  26   c ,  26   d ) as a first unit and developing units  4  ( 4   a ,  4   b ,  4   c ,  4   d ) as a second unit. The drum unit  26  includes at least the photosensitive drum  1 . In this embodiment, the drum unit  26  includes the photosensitive drum  1 , the charging roller  2  and the cleaning member  6 . Further, the developing unit  4  includes the developing roller  25  and a rotatable member, described later, for transmitting the driving force to the developing roller  25 . 
     To a frame  27  of the drum unit  26 , the photosensitive drum  1  is rotatably mounted via a front drum bearing  10  and a rear drum bearing  11 . The photosensitive drum  1  is provided with a drum coupling  16  and a flange  19  as a first drum coupling member in one end side with respect to an axial direction thereof. 
     At a periphery of the photosensitive drum  1 , as described above, the charging roller  2  and the cleaning member  6  are disposed. The cleaning member  6  is constituted by an elastic member formed with a rubber blade and a cleaning supporting member  8 . A free end portion of the rubber blade disposed in contact with the photosensitive drum  1  counter directionally to a rotational direction of the photosensitive drum  1 . Further, a residual toner removed from the surface of the photosensitive drum  1  by the cleaning member  6  falls into a removed toner chamber  27   a.    
     By transmitting a driving force of a main assembly driving motor (not shown) as a driving source to the photosensitive drum  1 , so that the photosensitive drum  1  is rotationally driven depending on an image forming operation. The charging roller  2  is rotatably mounted to the drum unit  26  via a charging roller bearing  28 . Further, the charging roller  2  is urged against the photosensitive drum  1  by a charging roller urging member  46 , thus being rotated by the rotation of the photosensitive drum  1 . 
     The developing unit  4  has a constitution including the developing roller  26 , rotating in contact with the photosensitive drum  1  in an arrow B direction, and a developing device frame  31  for supporting the developing roller  25 . Further, the developing unit  4  is constituted by a developing chamber  31   b  in which the developing roller  25  is disposed and by a toner accommodating chamber  31   c , disposed below the developing chamber  31   b , for accommodating container for accommodating the toner. These chambers are partitioned by a partition wall  31   d . Further, the partition wall  31   d  is provided with an opening  31   e  through which the toner passes when the toner is fed from the toner accommodating chamber  31   c  to the developing chamber  31   b . The developing roller  25  is rotatably supported by the developing (device) frame  31  via a front developing (means) bearing  12  and a rear developing (means) bearing  13  provided in both sides of the developing device frame  31 , respectively. 
     Further, at a periphery of the developing roller  25 , a developer supplying roller  34  as a rotatable member rotatable in contact with the developing roller  25 , and a developing blade  35  for regulating a toner layer on the developing roller  25  are provided. Further, in the toner accommodating chamber  31   c  in the developing frame  31 , a toner feeding member  36  for feeding the toner into the developing chamber  31   b  through the opening  31   e  while stirring the toner accommodated in the toner accommodating chamber  31   c  is provided. 
       FIG. 4  is a general perspective view of the process cartridge  70 .  FIG. 5  is a general perspective view of the developing unit  4 . To the drum unit  26 , the developing unit  4  is rotatably mounted. A front supporting pin  14  and a rear supporting pin  15  which are press-fitted in the drum unit frame  27  are engaged with hang holes  12   a  and  13   a , respectively, of the rear developing bearing  13 . As a result, the developing unit  4  is rotatably supported by the frame  27  with the supporting pins  14  and  15  as rotation shafts. 
     Further, the frame  27  is provided with a front drum bearing  10  and a rear drum bearing  11  which rotatably support the photosensitive drum  1 . The rear drum bearing  11  supports a drum coupling  16  coupled to the photosensitive drum  1 . Further, the front drum bearing  10  supports the flange. Here, the drum coupling  16  is a drum coupling member for transmitting a rotational driving force from the apparatus main assembly  100 A to the photosensitive drum  1 . 
     The developing frame  31  is provided with the front and rear developing bearings  12  and  13  for rotatably supporting the developing roller  25 . Further, the developing unit  4  is constituted so as to be urged against the drum unit  26 , during image formation of the process cartridge  70 , by an urging spring  32  provided at each of ends of the developing frame  31 . By these urging spring  32 , an urging force for bringing the developing roller  25  into contact with the photosensitive drum  1  with, as rotation centers, the hang holes  12   a  and  13   a  of the front and rear developing bearings  12  and  13  is generated. 
     (Insertion and Mounting Constitution of Process Cartridge into Image Forming Apparatus Main Assembly) 
     In  FIG. 6 , a constitution in which the process cartridge  70  is inserted into the image forming apparatus  100  will be described. In this embodiment, a constitution in which the process cartridges  70  are inserted through openings  101  ( 101   a ,  101   b ,  101   c ,  101   d ) of the image forming apparatus  100  is a constitution in which the process cartridges  70  are inserted from the front side to the rear side in a direction (arrow F direction in the figure) parallel to an axial direction of the photosensitive drums  1 . 
     In the image forming apparatus  100 , main assembly upper mounting guide portions  103  ( 103   a ,  103   b ,  103   c ,  103   d ) ( FIG. 6 ) which are first main assembly guide portions are provided in an upper side with respect to a vertical direction. Further, in the image forming apparatus  100 , main assembly lower mounting guide portions  102  ( 102   a ,  102   b ,  102   c ,  102   d ) ( FIG. 6 ) which are second main assembly mounting guide portions are provided in a lower side with respect to the vertical direction. Each of the main assembly upper guide portions  103  and the main assembly lower guide portions  102  has a guide shape extending along an insertion direction F of each of the process cartridge  70 . 
     The process cartridge  70  is placed in a front side of the main assembly lower mounting guide portion  102  with respect to a mounting direction and then is moved in the insertion direction F along the main assembly upper and lower mounting guide portions  102  and  103 , thus being inserted into the image forming apparatus  100 . 
     An operation of mounting the process cartridge  70  into the apparatus main assembly  100 A will be described.  FIG. 7( a )  is a schematic view for illustrating a state before mounting of the process cartridge  70  into the apparatus main assembly  100 A. 
       FIG. 7( b )  is a schematic view for illustrating a state during the mounting of the process cartridge  70  into the apparatus main assembly  100 A. The main assembly lower mounting guide portion  102  provided in the apparatus main assembly  100 A is provided with a main assembly(-side) pressing member  104  and a main assembly(-side) pressing spring  105  which press and position the process cartridge  70  against the apparatus main assembly. When the process cartridge  70  is mounted in the apparatus main assembly  100 A, a guide portion  27   b  of the frame  27  runs on the main assembly pressing portion  104 , so that the process cartridge  70  moves upward with respect to the vertical direction of the image forming apparatus  100 . Then, the guide portion  27   b  of the frame  27  is in a state in which the guide portion  27   b  is spaced from a guide surface of the main assembly lower mounting guide portion  102 . 
       FIG. 7( c )  is a schematic view for illustrating a state in which the process cartridge  70  is mounted into the apparatus main assembly  100 A until the process cartridge  70  abuts against a rear(-side) plate  98 . In the state in which the guide portion  27   b  of the frame  27  runs on the main assembly pressing member  104 , when the mounting of the process cartridge  7  is further continued, an abutting portion provided on the drum unit  26  contacts the rear plate  98  of the apparatus main assembly  100 A. 
       FIG. 7( d )  and  FIG. 8  are schematic views for illustrating a state in which the process cartridge  70  is positioned relative to the apparatus main assembly  100 A. In a state of (c) of  FIG. 7 , in interrelation with closing of a front door  96  of the apparatus main assembly  100 A, the main assembly lower mounting guide portion  102  including the main assembly pressing member  104  and the main assembly pressing spring  105  moves upward with respect to the vertical direction of the image forming apparatus  100 . With the movement, also a cartridge(-side) positioning portion  11   a  provided at an upper portion of the rear drum bearing  11  contacts an abutting portion  98   a  which is a main assembly(-side) positioning portion of the rear plate  98 . 
     Then, by the contact of the cartridge positioning portion  11   a  provided at the upper portion of the rear drum bearing  11  with an abutting portion  97   a  which is a main assembly(-side) positioning portion of a front plate  97 , the position of the process cartridge  70  relative to the apparatus main assembly  100 A is determined. Also in this state, the guide portion  27   b  of the frame  27  is spaced from the guide surface of the main assembly lower mounting guide portion  102 , so that the process cartridge  70  is in a state in which the process cartridge  70  is pressed by a spring force, of the main assembly pressing spring  105 , received from the main assembly pressing member  104 . 
     Further, the frame  27  is provided on a side surface thereof with a boss  27   c  as a rotation stopper for the process cartridge  70 , and the boss  27   c  engages with a rotation preventing hole (portion)  98   b  provided in the rear plate  98 . Thus, the process cartridge  70  is prevented from rotating in the apparatus main assembly  100 A. 
     (Spacing Mechanism Between Photosensitive Drum and Developing Roller in Process Cartridge) 
     In the process cartridge  70  according to this embodiment, the photosensitive drum  1  and the developing roller  25  are capable of being contacted to and spaced from each other. Here, a contact and separation (spacing) mechanism between the photosensitive drum  1  and the developing roller  25  will be described with reference to  FIGS. 9 and 10 . 
     In  FIG. 9 , the apparatus main assembly is provided with a spacing member  94  at a predetermined position with respect to a longitudinal direction of the process cartridge  70 . A spacing force receiving portion  31   a  of the developing frame  31  receives a force from the spacing member  94  moving in an arrow N direction, whereby the developing unit  4  of the process cartridge  70  moves the developing roller  25  to a spaced position where the developing roller  25  is spaced from the photosensitive drum  1 . 
     Further, as shown in  FIG. 10 , when the spacing member  94  moves in an arrow P direction away from the spacing force receiving portion  31   a , the developing unit  4  is rotated in an arrow T direction about the holes  12   a  and  13   a  of the front and rear developing bearings  12  and  13  by the urging force of the urging springs  32  ( FIG. 5 ) provided at the ends of the developing frame  31 . Then, the developing unit  4  is moved to a contact position, so that the developing roller  25  and the photosensitive drum  1  are in contact with each other. By this contact and separation mechanism, during the image formation, the developing unit  4  is moves to a contact position, and when the image formation is not effected, the developing unit  4  moves to and is held at the spaced position. By that, an effect of suppressing the influence of deformation of the developing roller  25  on an image quality is obtained. 
     (Spacing Mechanism when Process Cartridge is Mounted) 
     The contact and separation mechanism when the process cartridge  70  is mounted in the apparatus main assembly  100 A will be described using  FIGS. 11 and 12 . 
     When the process cartridge  70  is mounted in the apparatus main assembly  100 A, the developing unit  4  is in the contact portion, and the photosensitive drum  1  and the developing roller  25  are in contact with each other. At the time of completion of the mounting of the process cartridge  70  in the apparatus main assembly  100 A and at the time of end of the image forming operation of the image forming apparatus  100 , the developing unit  4  is in the spaced position, and the photosensitive drum  1  and the developing roller  25  are spaced from each other. 
     Therefore, when the process cartridge  70  is mounted in the apparatus main assembly  100 A, there is a need to move the process cartridge  70  from the contact position to the spaced position, and a constitution thereof will be described using  FIGS. 11-14 . As shown in  FIG. 11 , the apparatus main assembly  100 A is provided with an image forming apparatus opening  101  for permitting mounting of the process cartridge  70 . Further, as shown in  FIGS. 11 and 12 , the apparatus main assembly  100 A is provided with a spacing guide portion  93  contacting a spacing force receiving portion  31   a  provided on the developing unit  4  of the process cartridge  70 . 
     As shown in (a) of  FIG. 13  and (a) of  FIG. 14 , before the process cartridge  70  enters the apparatus main assembly  100 A, the developing unit  4  is in the contact position, and the photosensitive drum  1  and the developing roller  25  are in contact with each other. Then, as shown in (b) of  FIG. 13  and (b) of  FIG. 14 , when the process cartridge  70  is mounted into the apparatus main assembly  100 A, first, the guide portion  27   b  provided integrally with the frame is mounted on the main assembly lower mounting guide portion  102  provided in the apparatus main assembly  100 A. Then, the spacing force receiving portion  31   a  provided on the developing frame  31  contacts a chamfered portion  93   a  which is an inclined surface obliquely inclined relative to the spacing guide portion  93 . 
     When the process cartridge  70  is caused to further enter the apparatus main assembly, as shown in (c) of  FIG. 13  and (c) of  FIG. 14 , the spacing force receiving portion  31   a  moves along the chamfered portion  93   a , so that the developing unit  4  rotates in an arrow J direction about a rear supporting pin  15  as a rotation center. Then, the developing unit  4  moves in an arrow K direction to the spaced position. Then, when the process cartridge  70  is positioned in the apparatus main assembly  100 A, as shown in (d) of  FIG. 13  and (d) of  FIG. 14 , the spacing force receiving portion  31   a  is in a contact state with the spacing member  94  disposed downstream of the spacing guide portion  93  with respect to the mounting direction. At that time, the developing unit  4  is in the spaced position, so that the process cartridge  70  can be mounted in the apparatus main assembly  100 A while keeping the developing roller  25  in the spaced state from the photosensitive drum  1 . 
     (Constitution of Photosensitive Drum Driving Mechanism, Developer Supplying Roller Supporting and Developing Coupling Portion in Process Cartridge) 
     Next, a constitution of a coupling portion in the developing unit  4 , the developer supplying roller  34  which is a rotatable member, and a supporting constitution of the developer supplying roller  34  according to this embodiment will be described using  FIGS. 15-18 . 
       FIG. 15  is an illustration showing a longitudinal one end side (rear side) of a supporting portion for the developing roller  25  and the developer supplying roller  34 . In  FIG. 15 , a developing roller shaft  25   j  of the developing roller  25  and a developer supplying roller shaft  34   j  of the developer supplying roller  34  are rotatably engaged with an inner peripheral surface of the rear developing bearing  13 . Here, the supporting constitution in the longitudinal one end side of the developing roller  25  and the developer supplying roller  34  was described, but also in the other longitudinal one end side, similarly, the bearing portion is integrally provided with the bearing member, and the developing roller shaft  25   j  and the developer supplying roller shaft  34   j  are rotatably engaged in the other end side. Further, at the coupling portion, an Oldham coupling  20  which is a shaft coupling member is used. In this embodiment, a constitution in which each of the developer supplying roller  34  and the developing roller  25  is supported by the developing unit  4  is employed. For that reason, the developer supplying roller  34  and the developing roller  25  are always in contact with each other independently of the contact or spaced state between the photosensitive drum  1  and the developing roller  25 . 
     Using  FIG. 16 , a constitution of the Oldham coupling  20  will be described. Here, in order to describe the constitution of the Oldham coupling  20 , the rear developing bearing  13  is not shown. As shown in  FIG. 16 , the Oldham coupling  20  is constituted by a follower-side engaging portion  21  as a driven portion, an intermediary engaging portion as an intermediary portion, and a driving-side engaging portion  23  as a drive receiving portion. 
     The follower-side engaging portion  21  is fixed and mounted a shaft  34   j  of the developer supplying roller  34  in one end side with respect to an axial direction. As a fixing method, there are a method in which connection is made by a spring pin or a parallel pin and a method in which as shown in  FIG. 16 , the developer supplying roller shaft  34   j  is provided with a cut portion  34   k  at an end surface thereof and also a hole in the follower-side engaging portion  21  side is similarly shape and is engaged with the cut portion  34   k.    
     The driving-side engaging portion  23  is a portion for receiving a driving force of a driving source of the main assembly. Further, a shaft portion  23   d  of the driving-side engaging portion  23  is rotatably held in a hole  41   d  of a holding portion  41 . This holding portion is movable in a direction perpendicular to the axial direction of the developing roller. Further, the driving-side engaging portion  23  is integrally formed with three projections  23   c   1 ,  23   c   2  and  23   c   3  engageable with a main assembly(-side) developing (means) coupling  91  ( FIG. 18 ) which is a second main assembly(-side) drive transmitting member of the  100 A described later. 
     This Oldham coupling  20  allows a deviation between an axis of the main assembly developing coupling  91  which is a driving force providing driving member provided in the main assembly and an axis of the developer supplying roller  34 , and transmits a rotational driving force (second rotational driving force) from the apparatus main assembly  100 A to the developer supplying roller  34 . Further, the Oldham coupling  20  is capable of transmitting a rotational driving force (second rotational driving force) from the apparatus main assembly  100 A to the developer supplying roller  34  in a state in which the developing unit  4  is in the contact position and in the spaced position. 
     In  FIG. 17 , a constitution of the Oldham coupling  20  will be described in further detail using sectional views.  FIG. 17( a )  is a sectional view of the Oldham coupling  20  cut in parallel to an arrow H direction in  FIG. 16 , and  FIG. 17( b )  is a schematic view of the Oldham coupling  20  cut in parallel to an arrow I direction in  FIG. 16 . In (a) of  FIG. 17 , the follower-side engaging portion  21  is integrally provided with a rib  21   a . The intermediary engaging portion  22  is provided with a groove  22   a , and the rib  21   a  and the groove  22   a  are engaged with each other so as to be movable in the arrow H direction of  FIG. 16 . In (b) of  FIG. 17 , the driving-side engaging portion  23  is integrally provided with a rib  23   b . The intermediary engaging portion  22  is provided with a groove  22   b , and the rib  23   b  and the groove  22   b  are engaged with each other so as to be movable in the arrow I direction of  FIG. 16 . In this embodiment, the H direction and the I direction are in the substantially perpendicular relationship. 
     The intermediary engaging portion  22  engages with the follower-side engaging portion  21  and the driving-side engaging portion  23 , and constitutes an intermediary portion for transmitting a driving force, inputted into the driving-side engaging portion  23 , to the follower-side engaging portion  21 , and is movable in a direction crossing the axial direction of the developer supplying roller  34  while maintaining engagement with each of the engaging portions  21  and  23 . 
       FIG. 18  is an illustration showing a constitution including the coupling provided on the process cartridge  70  and the coupling provided in the apparatus main assembly  100 A. As described above, at the end surface of the driving-side engaging portion  23  of the Oldham coupling  20  provided on the developing chamber  4 , the three projections  23   c   1 ,  23   c   2  and  23   c   3  projecting in the axial direction are formed. Further, a centering boss  23   a  to be aligned with the axis (rotation enter) of the main assembly developing coupling  91  projects in the axial direction from the end surface of the driving-side engaging portion  23 . 
     A guide portion  41   b  of the holding portion  41  is movable, in a direction crossing the axial direction of the developer supplying roller  34 , along the groove  43   a  of the side cover  43  fixed on the developing unit with an unshown screw or the like. That is, the driving-side engaging portion  23  is movable in the direction crossing the axial direction of the developer supplying roller. 
     In one end side of the photosensitive drum  1  with respect to the axial direction, a triangular drum coupling  16  which is a drum coupling portion is provided. In this embodiment, the drum coupling  16  is formed integrally with the flange of the photosensitive drum. In  FIG. 18 , the main assembly drum coupling  90  which is a drum driving member (first main assembly drive transmitting member) for transmitting the drive of the apparatus main assembly  100 A to the photosensitive drum  1  is provided with a hole  90   a  having a substantially triangular shape in cross section. The main assembly developing coupling  91  which is a driving member for providing the driving force (second rotational driving force) from the apparatus main assembly  100 A to the developer supplying roller  34  is provided with three holes  91   a   1 ,  91   a   2  and  91   a   3 . 
     The main assembly drum coupling  90  is urged in a direction of the process cartridge  70  by a drum pressing (urging) member  106  such as a compression spring. Further, the main assembly drum coupling  90  is movable in the axial direction of the photosensitive drum  1 . Further, in the case where the drum coupling  16  and the hole  90   a  of the main assembly drum coupling  90  are out of phase and in contact with each other when the process cartridge  70  is mounted in the apparatus main assembly  100 A, the main assembly drum coupling  90  is pushed by the drum coupling  16 , thus being retracted. Then by rotation of the main assembly drum coupling  90 , the drum coupling  16  and the hole  90   a  are engaged with each other, the rotational driving force is transmitted to the photosensitive drum  1 . 
     Further, the main assembly developing coupling  91  is urged in the direction of the process cartridge  70  toward a direction parallel to the axial direction of the photosensitive drum  1  by a developing (means) pressing (urging) member  107  such as a compression spring. However, the main assembly developing coupling  91  has no play with respect to the direction crossing the axial direction and is provided in the apparatus main assembly  100 A. That is, the main assembly developing coupling  91  not only rotates for transmitting the drive (driving force) but also in movable only in the axial direction. 
     When the driving-side engaging portion  23  and the main assembly developing coupling  91  are engaged with each other by causing the process cartridge  70  to enter the apparatus main assembly  100 A, the projections  23   c   1 - 23   c   3  and the holes  91   a   1 - 91   a   3  are out of phase in some cases. In this case, free ends of the projections  23   c   1 - 23   c   3  contact portions other than the holes  91   a   1 - 91   a   3 , so that the main assembly developing coupling  91  is retracted in the axial direction against an urging force of the developing pressing member  107 . However, when the main assembly developing coupling  91  rotates and the projections  23   c   1 - 23   c   3  and the holes  91   a   1 - 91   a   3  are in phase, the main assembly developing coupling  91   a  advances by the urging force of the developing pressing member  107 . 
     Then, the projections  23   c   1 - 23   c   3  and the holes  91   a   1 - 91   a   3  engage with each other, and also the centering boss  23   a  which is an engaging portion positioning portion and the centering hole  91   b  which is a transmitting member positioning portion engage with each other, so that the driving-side engaging portion  23  and the axis (rotation center) of the main assembly developing coupling  91  coincide with each other. Then, by rotation of the main assembly coupling  91 , the projections  23   c   1 - 23   c   3  and the holes  91   a   1 - 91   a   3  engage with each other, respectively, so that the rotational driving force is transmitted to the developer supplying roller  34 . Next, rotation of the developing roller  25  will be described. The developer supplying roller  34  is provided with the driving-side engaging portion  23  in one end side and is provided with a first gear in the other end side with respect to the longitudinal direction (the axial direction of the developer supplying roller, the axial direction of the developing roller). Incidentally, in this embodiment, the axial direction of the developer supplying roller and the axial direction of the developing roller are is a substantially parallel relationship. On the other hand, the developing roller  25  is provided with a second gear engageable with the above gear. By this constitution, the rotational driving force is transmitted to the developing roller  25  drive-connected to the developer supplying roller  34  by the gears in the other end side with respect to the longitudinal direction. 
     Here, the drive transmission to the main assembly drum coupling  90  and the main assembly developing coupling  91  is made by a motor provided in the apparatus main assembly  100 A. By this, the photosensitive drum  1  and the developer supplying roller  34  receive the driving force from the image forming apparatus main assembly independently of each other. Incidentally, the motor may employ a constitution using a single motor per each of the process cartridges  70  for the respective colors and a constitution in which the drive is transmitted to some process cartridges by the single motor. 
     (Operation of Oldham Coupling During Contact and Separation Operation in Process Cartridge) 
     Next, an operation of the Oldham coupling  20  during a contact and separation operation between the developing roller and the photosensitive drum in the process cartridge  70  according to this embodiment will be described using  FIGS. 1, 19 and 20 . 
       FIG. 19  includes a side view and a longitudinal sectional view which show a state in which the developing unit  4  is positioned in the spaced position. In a state in which the developing unit is positioned in the spaced position by a spacing guide portion  93 , as shown in  FIG. 19 , the developing roller  25  and the photosensitive drum  1  are in a spaced state. 
     However, an arm portion  42   a  of an urging spring  42  which is an urging member constituted by a helical coil spring provided in a side cover  43  contacts a locking portion  41   c  of the holding portion  41 . By that, the driving-side engaging portion  23  is urged in a direction Q (direction toward the develop) crossing the axial direction of the photosensitive drum  1 . Then, a contact portion  41   a  of the holding portion  41  contacts a bearing contact portion  11   a  which is an abutting portion (stopping portion) provided on the rear drum bearing  11 , and engages with the bearing contact portion  11   a.    
     Here, the bearing contact portion  11   a  of the rear drum bearing  11  has a V-character shape. Then, the bearing contact portion  11   a  is formed by two surfaces (sides) parallel to the axis of the photosensitive drum  1  with respect to the axial direction of the photosensitive drum  1 . Further, by the contact of the holding portion  41  with this bearing contact portion  11   a , the holding portion  41  can be held in parallel to the axis of the photosensitive drum  1 . Further, the rear drum  11  is provided with the cartridge positioning portion  11   a  as a unit. Accordingly, the driving-side engaging portion  23  rotatably supported by the holding portion  41  is positioned with accuracy relative to the rear plate  98 , of the apparatus main assembly  100 A, to which the cartridge positioning portion  11   a  is to be positioned. Accordingly, the driving-side engaging portion  23  can be positioned with accuracy also relative to an axis  91   j  of the main assembly developing coupling  91  provided in the apparatus main assembly  100 A. 
     Incidentally, in this embodiment, as the member for urging the holding portion  41 , the urging spring  42  was used. However, an elastically deformable elastic portion is provided integrally with the holding portion  41  and thus may also be contacted to the bearing contact portion  11   a.    
     Next, when the driving-side engaging portion  23  engages with the main assembly developing coupling  91  and then rotates, the driving-side engaging  23  is positioned by the main assembly developing coupling  91 . At this time, a constitution in which the contact portion  41   a  of the holding portion  41  is spaced from the rear drum bearing  11 , i.e., the bearing contact portion  11   a  is formed. 
     For that reason, when the contact  70  enters the apparatus main assembly  100 A, an axis  23   j  of the driving-side engaging portion  23  will start engagement in a state in which the axis  23   j  is deviated from the axis  91   j  of the main assembly developing coupling  91  toward the photosensitive drum  1  side by a certain distance. From this state, when the process cartridge  70  further enters the apparatus main assembly  100 A, a constitution in which a taper-shaped chambered portion provided at an outer periphery of a free end of the centering boss  23   a  and a chamfered portion provided in the hole  91   b  correspondingly thereto engage with each other while contacting each other, and thus engage with each other while correcting deviation of the axis center is formed. 
     Then, the main assembly developing coupling  91  rotates, and when the projections  23   c   1 - 23   c   3  ( FIG. 18 ) of the driving-side engaging portion  23  and the holes  91   a   1 - 91   a   3  ( FIG. 18 ) of the main assembly developing coupling  91  are in phase with each other, the centering boss  23   a  and the hole  91   b  engage with each other. By that, the axis  23   j  of the driving-side engaging portion  23  and the axis  91   j  of the main assembly developing coupling  91  coincide with each other. Then, the driving-side engaging portion  23  is positioned by the main assembly developing coupling  91 , and therefore the holding portion  41  is spaced from the rear drum bearing  11 , i.e., the bearing contact portion  11   a.    
     Further,  FIG. 1  includes a side view and a longitudinal sectional view which show a state in which the developing unit  4  is positioned in the contact portion. The spacing member  94  ( FIG. 10 ) of the apparatus main assembly  100 A operates, so that the developing unit  4  of the process cartridge  70  rotationally moves in an arrow T direction about the rear supporting pin  15  which supports the rear developing bearing  13 . Then, the developing unit  4  moves to the contact position, where the develop  1  and the developing roller  25  contact each other. Here, even when the developing unit  4  moves to the contact position, the driving-side engaging portion  23  and the main assembly developing coupling  91  are kept in an engaged state. 
     Further, as shown in  FIGS. 1 and 20 , even in a state of either position of the spaced position and the contact position of the developing unit  4 , the intermediary engaging portion  22  engages with the driving-side engaging portion  23  and the follower-side engaging portion  21 . Accordingly, the intermediary engaging portion  22  enables movement of the driving-side engaging portion  23  and the follower-side engaging portion  21  while maintaining engagement thereof with the driving-side engaging portion  23  and the follower-side engaging portion  21  also when the developing unit  4  moves between the spaced position and the contact position. 
     When the intermediary engaging portion  22  rotates while maintaining the engagement with the driving-side engaging portion  23  and with the follower-side engaging portion  21 , chips are produced due to the friction at the engaging portions. By this, the friction forces at the engaging portions increase with the result of non-constant rotational speed of the driving-side engaging portion  23  engaged with the main assembly developing coupling  91 . This may adversely affect the image produced by the apparatus. 
     As shown in  FIGS. 24 and 25 , in order to remove the produced chips, a flexible sheet  252  is contacted to at least a part of the Oldham coupling  20  (the intermediary engaging portion  22 , the driving-side engaging portion  23 , and/or the follower-side engaging portion  21 ). The flexible sheet  252  is bonded using the a double-sided tape or the like on a rotatable supporting member  251  which is rotatably supported at one longitudinal end of the developing roller  25 , and is intermittently contacted to the part of the Oldham coupling  20  by the rotation of the developing roller  25  to remove the produced chips. 
     (Positioned Relationship Between Bearing Contact Portion and Photosensitive Drum in Process Cartridge) 
     Next, a positional relationship between the bearing contact portion  11   a  and the photosensitive drum  1  in the process cartridge  70  according to shift embodiment will be described using  FIGS. 19 and 21 . 
       FIG. 19  includes a side view and a sectional view of a state in which the developing roller  25  and the photosensitive drum  1  are spaced from each other in this embodiment. 
     Here, the bearing contact portion  11   a  which is a feature portion in this embodiment will be described. 
     The bearing contact portion  11   a  is a contact portion provided on the rear drum bearing  11  against which the holding portion  41  abuts. When the driving-side engaging portion  23  engages with the main assembly developing coupling  91 , the position of the driving-side engaging portion  23  is determined by the main assembly developing coupling portion. However, when the process cartridge  70  is inserted into the main assembly in the state in which the developing roller and the photosensitive drum are spaced from each other, the driving-side engaging portion  23  does not readily engage with the main assembly developing coupling depending on the position of the driving-side engaging portion. In this embodiment, the position of the main assembly developing coupling is determined by the main assembly, and therefore in order to facilitate engagement between the driving-side engaging portion and the main assembly developing cartridge during the insertion of the process cartridge into the main assembly, there is a need to determine the position of the driving-side engaging portion. For that reason, in this embodiment, a constitution in which in the case where the driving-side engaging portion and the main assembly developing coupling do not engage with each other, the holding portion  41  is urged against the bearing contact portion  11   a  by the spring  42  is employed. By that constitution, the holding portion  41  is positioned to the bearing contact portion  11   a , with the result that even in the case where the driving-side engaging portion and the main assembly developing cartridge do not engage with each other, the position of the driving-side engaging portion is determined. 
     As shown in  FIG. 19 , a shape of the bearing contact portion  11   a  is required to be such a shape that the bearing contact portion  11   a  contacts the holding portion at least at two points. Therefore, in this embodiment, the bearing contact portion  11   a  has a V-character shape. In this embodiment, in  FIG. 19 , contact points (contact portions) are 411 and 412. Then, in this embodiment, all the contact points are disposed so as to be outside the outer peripheral surface of the photosensitive drum  1  on a plane perpendicular to the rotational axis  90   j  of the photosensitive drum. Further, the bearing contact portion  11   a  is required to be disposed in a driving member (developing roller) side than the outer peripheral surface of the develop  1  with respect to a direction of a rectilinear line L 1  connecting a rotation center  1   a  of the photosensitive drum  1  and a rotation center  34   a  of the developer supplying roller  34  which is a driving member for receiving drive from the main assembly via the coupling. In this embodiment, a constitution in which with respect to the direction of the rectilinear line L 1  connecting the rotation center  1   a  of the photosensitive drum  1  and the rotation center  34   a  of the developer supplying roller  34  which is the driving member for receiving drive from the main assembly via the coupling, the contact point closest to the photosensitive drum is disposed between the outer peripheral surface of the photosensitive drum  1  and the rotation center  34   a  was employed. By such a constitution, even when the process cartridge is downsized, a distance between an axis of the apparatus main assembly-side drive transmitting portion for transmitting the rotational driving force to the photosensitive drum and an axis of the apparatus main assembly-side drive transmitting portion for transmitting the rotational driving force to the second unit is capable of being made large. Further, in this embodiment, the contact points  411  and  412  of the bearing contact portion  11   a  against which the holding portion  41  abuts were provided outside the outer peripheral surface of the photosensitive drum  1  and inside the outer peripheral surface of the developing roller  25 . In this embodiment, a constitution in which all the contact points are provided inside the outer peripheral surface of the developing roller  25  is employed, but when a constitution in which at least one contact point is provided inside the outer peripheral surface of the developing roller  25 , it is possible to reduce an excessive degree of upsizing of the process cartridge. Further, at least all the contact points are required to be positioned between the center of the photosensitive drum and the center of the developer supplying roller. 
     Next, a distance between the axis  90   j  of the main assembly drum coupling  90  and the axis  91   j  of the main assembly developing coupling  91  is La. As a comparison example, a constitution in which the bearing contact portion  11   a  against which the holding portion  41  abuts is provided inside the outer peripheral surface of the photosensitive drum  1  is shown in  FIG. 21 . In this figure, the bearing contact portion  11   a  is inside the peripheral speed of the photosensitive drum  1 , and therefore all the contact points between the bearing contact portion  11   a  and the holding portion are inside the outer peripheral surface of the photosensitive drum  1 . At this time, a distance between the axis  90   j  of the main assembly drum coupling  90  and the axis  91   j  of the main assembly developing coupling  91  is Lb. 
     In this way, by providing the bearing contact portion, against which the holding portion  41  abuts, outside the outer peripheral surface of the photosensitive drum  1 , it becomes possible to make the distance between the axis  90   j  of the main assembly drum coupling  90  and the axis  91   j  of the main assembly developing coupling  91  larger (La&gt;Lb). 
     Therefore, it becomes possible to further ensure a clearance between the main assembly drum coupling  90  and the main assembly developing  91 , so that a degree of flexibility in design and arrangement of the apparatus main assembly  100 A can be improved. Further, also in the process cartridge  70 , the photosensitive drum  1  and the developing roller  25  are made to have a small diameter, so that it also becomes possible to further downsize the process cartridge  70 . 
     In  FIG. 19 , an example in which the bearing contact portion  11   a  against which the holding portion  41  abuts was provided outside the outer peripheral surface of the photosensitive drum  1  and inside the outer peripheral surface of the developing roller  25  was shown. Here, as shown in  FIG. 22 , even when the bearing contact portion  11   a  against which the holding portion  41  abuts is outside the outer peripheral surface of the photosensitive drum  1  and is outside the outer peripheral surface of the developer supplying roller  34 , a similar effect can be obtained. 
     Further, as shown in  FIG. 23 , even when the bearing contact portion  11   a  against which the holding portion  41  abuts is outside the outer peripheral surface of the photosensitive drum  1 , outside the outer peripheral surface of the developing roller  25 , and is inside the outer peripheral surface of the developer supplying roller  34 , a similar effect can be obtained. 
     However, as shown in  FIG. 22 , in the case where the bearing contact portion  11   a  against which the holding portion  41  abuts is outside the outer peripheral surface of the photosensitive drum  1  and is in a position deviated from between the photosensitive drum center and the developer supplying roller center and is outside the outer peripheral surface of the developer supplying roller  34 , there is a need to transmit the second rotational driving force, inputted from the apparatus main assembly  100 A, to the developer supplying roller  34  and the like via the gears  110   a ,  110   b  and the like, thus leading to an increase of the number of parts. 
     Further, as shown in  FIG. 23 , in the case where the bearing contact portion  11   a  against which the holding portion  41  abuts is outside the outer peripheral surface of the photosensitive drum  1 , outside the outer peripheral surface of the developing roller  25 , and is inside the outer peripheral surface of the developer supplying roller  34 , when the Oldham coupling  20  is provided on the developer supplying roller shaft in order to prevent the increase of the number of parts, the driving-side engaging portion  23  becomes small and leads to a lowering in strength. Therefore, the bearing contact portion  11   a  against which the holding portion  41  abuts may desirably be outside the outer peripheral surface of the photosensitive drum  1  and is between the center of the photosensitive drum and the center of the developer supplying roller (rotatable member), and further is outside the outer peripheral surface of the developer supplying roller. 
     By this, it becomes possible to make the distance between the axis  90   j  of the main assembly drum coupling  90  and the axis  91   j  of the main assembly developing coupling  91  large while avoiding the increase of the number of parts due to an increase of the number of the driving gears and the lowering in strength of the drive engaging portion. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, there are provided a process cartridge and an image forming apparatus which are capable of broadening an interval between drive input to a photosensitive drum and drive input to a developing roller.