Abstract:
A developing apparatus includes a developer container. An agitating member agitates developer contained in the developer container. A drive transmitting member transmits power to the agitating member by engaging a rotary shaft of the agitating member. A bearing is adapted to rotatably hold the drive transmitting member to the developer container. The bearing includes a notched portion having a rotation regulating and positioning function to prevent the bearing from being dislodged from the developer container.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a developing apparatus used with an image forming apparatus such as a copying machine, a printer and the like, and more particularly, it relates to a developing apparatus including a developer containing container having an agitating member therein. 
     Here, an electrophotographic image forming apparatus serves to form an image on a recording medium by using an electrophotographic image forming process, and as examples of the electrophotographic image forming apparatus, for example, there are an electrophotographic copying machine, an electrophotographic printer (for example, laser beam printer, LED printer and the like), an electrophotographic facsimile apparatus, electrophotographic word processor and the like. 
     Further, a process cartridge may incorporate electrifying means, developing means or cleaning means, and an electrophotographic photosensitive member as a cartridge unit which is detachably attachable to a main body of an image forming apparatus or may incorporate at least one of electrifying means, developing means and cleaning means, and an electrophotographic photosensitive member as a cartridge unit which is detachably attachable to main body of an image forming apparatus or may incorporate at least developing means, and an electrophotographic photosensitive member as a cartridge unit which is detachably attachable to a main body of an image forming apparatus. Incidentally, the present invention also relates to an process cartridge including developing means. 
     2. Related Background Art 
     Conventionally, in connection with an image forming apparatus using an electrophotographic image forming process, there has been proposed a process cartridge system in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally incorporated as a cartridge unit which is detachably attachable to a main body of an image forming apparatus. According to such a process cartridge system, since the maintenance of the apparatus can be performed by an operator himself without any expert, the operability can be improved considerably. Thus, the process cartridge system has widely been used in image forming apparatuses. 
     In such a process cartridge, a bearing member attached to a developing apparatus is provided with a seal member for preventing leakage of toner. 
     For example, there are bearings disclosed in Japanese Patent Laid-Open Application No. 11-133738 (FIG. 8) and Japanese Patent Laid-Open Application No. 11-102107 (FIG. 7). 
     However, there is no idea that these bearings can easily be disassembled to facilitate the maintenance or to facilitate the recycle of the bearings. 
     SUMMARY OF THE INVENTION 
     The present invention is made in consideration of the above-mentioned conventional circumstances, and an object of the present invention is to provide a developing apparatus having a bearing which can easily be disassembled. 
     Another object of the present invention is to provide a developing apparatus comprising a developer containing container, an agitating member for agitating developer contained in the developer containing container, a drive transmitting member for transmitting a power to the agitating member by engaging a rotary shaft of the agitating member, and a bearing adapted to rotatably hold the drive transmitting member and attached to the developer containing container, and wherein the bearing has dislodgment preventing means with respect to the developer containing container. 
    
    
     The other objects and features of the present invention will be more apparent from the following detailed explanation of the invention referring to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of an electrophotographic image forming apparatus; 
     FIG. 2 is a longitudinal sectional view of a process cartridge; 
     FIG. 3 is a front view of the process cartridge; 
     FIG. 4 is a right side view of the process cartridge; 
     FIG. 5 is a left side view of the process cartridge; 
     FIG. 6 is a plan view of the process cartridge; 
     FIG. 7 is a back view of the process cartridge; 
     FIG. 8 is a front perspective view of the process cartridge, looked at from the right; 
     FIG. 9 is a rear perspective view of the process cartridge, looked at from the left; 
     FIG. 10 is a perspective view of the process cartridge in a reverse condition, looked at from an oblique rear side; 
     FIG. 11 is a front view of an electrifying unit; 
     FIG. 12 is a front view of the electrifying unit of FIG. 11, with a blade omitted; 
     FIG. 13 is a back view of a developing unit, with a rear cover omitted; 
     FIG. 14 is a front view of the developing unit, with a front cover omitted; 
     FIG. 15 is a perspective view illustrating interior of the rear cover; 
     FIG. 16 is a perspective view illustrating interior of the front cover; 
     FIG. 17 is a side view of the developing unit; 
     FIG. 18 is a front view showing a support portion for a developing sleeve; 
     FIG. 19 is a longitudinal sectional view showing support for an electrophotographic photosensitive drum and a driving device; 
     FIG. 20 is a perspective view of a driving side drum flange; 
     FIG. 21 is a perspective view of the process cartridge, with the rear cover omitted, looked at from a lower oblique rear side; 
     FIG. 22 is a perspective view showing assembling of a bearing member; 
     FIG. 23 is a longitudinal sectional view of the bearing member; 
     FIG. 24 is a sectional view showing a connection between an agitating screw and an agitating gear; 
     FIG. 25 is a perspective view of the bearing member; 
     FIG. 26 is a longitudinal sectional view of a bearing member according to another embodiment of the present invention; and 
     FIG. 27 is a sectional view showing a connection between an agitating screw and an agitating gear according to another embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be explained in connection with embodiments thereof with reference to the accompanying drawings. 
     In the following description, a term “longitudinal direction” means a direction transverse to a conveying direction of a recording medium and parallel with the recording medium. Further, a term “upper” of a process cartridge means an upper side of the process cartridge in a mounting condition. 
     FIG. 1 is a view showing an image forming apparatus to which the present invention is applied. The image forming apparatus includes image forming portions  31 Y,  31 M,  31 C and  31 BK for forming toner images on photosensitive drums as image bearing members, an intermediate transfer belt  4   a  to which the toner images are temporarily transferred, a secondary transfer roller  40  as transferring means for transferring the toner images on the belt  4   a  onto a recording medium  2 , sheet feeding means for feeding out the recording medium  2  between the intermediate transfer belt  4   a  and the secondary transfer roller  40 , sheet conveying means for conveying the recording medium to the transferring means, fixing means, and sheet discharging means. 
     Now, image formation will be described. 
     As shown, a sheet feeding cassette  3   a  for stacking and containing a plurality of recording media  2  (for example, recording papers, OHP sheets, cloths or the like) is detachably mounted to the image forming apparatus. The recording media  2  picked up from the sheet feeding cassette  3   a  by means of a pick-up roller  3   b  are separated one by one by means of a pair of retard rollers  3   c , and the separated recording medium is conveyed to a registration roller pair  3   g  by pairs of conveying rollers  3   d,    3   f.    
     When the recording medium  2  is conveyed, the registration roller pair  3   g  is stopped, so that, by abutting the recording medium against a nip of the registration roller pair, skew-feed of the recording medium  2  is corrected. 
     In case of a four-drum full-color system, as shown, four process cartridges BY, BM, BC, BB including image bearing members for yellow, magenta, cyan and black colors are juxtaposed. Optical scanning systems  1 Y,  1 M,  1 C,  1 BK are associated with the respective process cartridges BY, BM, BC, BB, so that, after respective color toner images are formed on the photosensitive drums in response to image signals, the toner images are successively transferred onto the intermediate transfer belt  4   a  (running in a direction shown by the arrow) in a superimposed fashion by means of transfer rollers  4  ( 4 Y,  4 M,  4 C,  4 BK). 
     Thereafter, the recording medium  2  is sent out to the secondary transfer roller  40  at a predetermined timing, and the toner images on the intermediate transfer belt  4   a  are collectively transferred onto the recording medium  2 . After the toner images are fixed to the recording medium by means of a fixing device  5 , the recording medium is discharged onto a tray  6  on a main body  14  of the apparatus via pairs of discharge rollers  3   h,    2   i.    
     The image forming portions  31 Y,  31 M,  31 C and  31 BK constitute the process cartridges BY, BM, BC, BB, respectively, except for the optical scanning systems  1 Y,  1 M,  1 C,  1 BK. Since constructions of the process cartridges are identical, only the process cartridge BY will be described. 
     As shown in FIG. 2, in the process cartridge BY, electrifying means, an exposure portion, developing means and a transfer opening are arranged around a photosensitive drum  7 . In the illustrated embodiment, two-component developer including magnetic carrier powder is used. Thus, in the illustrated embodiment, although a usually used organic photosensitive member can be used as the photosensitive drum  7 , desirably, when a photosensitive member in which a surface layer made of material having resistance of 10 2  to 10 14  Ω·cm is provided on the organic photosensitive member or an amorphous silicon photosensitive member is used, charge injection electrifying can be realized, thereby preventing generation of ozone and reducing power consumption. Further, the electrifying ability can be improved. 
     Thus, in the illustrated embodiment, a photosensitive drum  7  in which a negatively charged organic photosensitive member is provided on a drum substrate made of aluminium was used. 
     The electrifying means comprises a magnet brush electrifier  8  using magnetic carrier. 
     In the electrifier  8 , a fixed magnet  8   b  is disposed within a hollow cylindrical electrifying roller  8   a  rotatably supported. After the transferring, residual toner remaining on the photosensitive drum  7  is picked up by the electrifier  8  rotated in a direction shown by the arrow. 
     In the illustrated embodiment, as the developing means, a system for effecting developing with two-component developer in a contacted condition (two-component contacting developing) is used. 
     FIG. 2 shows two-component magnet brush developing means  10  used in the illustrated embodiment. A developing sleeve  10   d  is a hollow cylinder rotatably supported. A fixed magnet  10   c  is disposed within the developing sleeve  10   d.  The developing sleeve  10   d  is rotated in the same direction as the photosensitive drum  7  so that a peripheral surface is shifted in a direction opposite to a shifting direction of a peripheral surface of the photosensitive drum  7 . The photosensitive drum  7  is not contacted with the developing sleeve  10   d  to define a gap of about 0.2 to 1.0 mm therebetween, so that the developing is effected in a condition that the developer is contacted with the photosensitive drum  7 . 
     The toner mixed with the carrier is supplied by agitating screws  10   g,    10   h  disposed within a casing partitioned by a longitudinal partition wall  10   f  except for both ends. The toner supplied from a toner supplying container (not shown) is dropped onto one end of the agitating screw log and is agitating while being sent toward one longitudinal direction and then is passed through an opening of the partition wall  10   f  at the other end and then is shifted toward one end by the agitating screw  10   h  and then is passed through an opening of the partition wall  10   f  at said one end and thus is agitated by the agitating screw  10   h  while being sent. In this way, the toner is circulated. 
     Now, a developing process for visualizing an electrostatic latent image formed on the photosensitive drum  7  by means of a two-component magnet brush method using the developing apparatus  10  and a developer circulating system will be explained. First of all, while the developer is being carried, the developer is regulated by a regulating blade, i.e., developing blade  10   e  disposed perpendicular to the developing sleeve  10   d,  thereby forming a thin developer layer on the developing sleeve  10   d.  When the thin developer layer is carried to a main developing pole, developer chains are formed by a magnetic force. The electrostatic latent image formed on the photosensitive drum  7  is developed by the developer chains, and, thereafter, the developer on the developing sleeve  10   d  is returned to a developing container  10   a  by a repelling magnetic field. 
     DC voltage and AC voltage are applied to the developing sleeve  10   d  from a power supply (not shown). In general, in the two-component developing method, when the AC voltage is applied, although developing efficiency is increased and a high quality image can be obtained, fog is apt to occur. Thus, normally, by providing potential difference between the CD voltage applied to the developing sleeve  10   d  and surface potential of the photosensitive drum  7 , during the developing, the toner is prevented from adhering to nonimage area. 
     The toner images are then transferred onto the intermediate transfer belt  4   a  by an intermediate transferring device  4 . In the intermediate transferring device  4 , the endless belt  4   a  is wound around a driving roller  4   b,  a driven roller  4  and a secondary transfer counter roller  4   d  to be turned in a direction shown by the arrow in FIG.  1 . Further, within the inside of the transfer belt  4   a , there are provided transfer electrifying rollers  4 Y,  4 M,  4 C and  4 BK, which transfer electrifying rollers generate pressurizing forces directing toward the photosensitive drums  7  from the inside of the belt  4   a . Meanwhile, by applying voltage to the transfer electrifying rollers from high voltage sources to effect electrifying having polarity opposite to that of the toner from the back side of the belt  4   a , the toner images on the photosensitive drums  7  are successively transferred onto the front surface of the intermediate transfer belt  4   a.    
     The intermediate transfer belt  4   a  can be made of polyimide resin. The material of the belt  4   a  is not limited to the polyimide resin, but, for example, dielectric plastic material such as polycarbonate resin, polyethylene telephalate resin, polychlorovinylidene resin, polyethylene naphthalate resin, polyether ether ketone resin, polyether sulfone resin or polyurethane resin, fluororubber or silicone rubber can suitably be used. 
     After the toner image is transferred, transfer-residual toner is remaining on the photosensitive drum  7 . If such residual toner is passed through the electrifier as it is, electrifying potential of only a remaining image portion will be reduced or a pre-image portion in a next image will become thinner or denser (referred to as “ghost phenomenon” hereinafter). Even after the residual toner is passed below the electrifying magnet brush contacted with the photosensitive drum  7 , in almost causes, the shape of the pre-image is remained as it is. Thus, as the photosensitive drum  7  is rotated, the residual toner reached to the electrifying area must be removed by the magnet brush electrifier  8  to erase history of the pre-image. Here, although the residual toner remaining on the photosensitive drum  7  often includes positively charged particles and negatively charged particles due to peel discharging in the transferring, it is desirable that the residual toner is positively charged to facilitate the collection of the toner into the magnet brush electrifier  8 . 
     In the illustrated embodiment, a conductive brush  11  is contacted with the photosensitive drum  7  between the intermediate transferring device  4  and the magnet brush electrifier  8  and bias having polarity opposite to the electrifying bias is applied to the brush. The positively charged residual toner is passed through the magnet brush electrifier  8 ; whereas, the negatively charged residual toner is temporarily caught by the conductive brush  11 , and, after electricity is removed, it is returned again onto the photosensitive drum  7 . In this way, the residual toner is apt to be collected toward the magnet brush. 
     (Construction of frame of process cartridge) 
     In the process cartridge B (BY, BM, BC, BB), an electrifying unit C in which the electrifying roller  8   a,  regulating blade  8   c  and electrifying brush  11  are incorporated via an electrifying frame  13  is assembled to a developing unit D in which the electrophotographic photosensitive drum  7  and developing means  10  are incorporated via a developing frame  12 . Further, the developing unit D and electrifying unit C are positioned and joined at both longitudinal ends by a front cover  16  and a rear cover  17  (FIG.  4 ). 
     FIGS. 3 to  7  show the process cartridge B (BY, BM, BC, BB), where FIG. 3 is a front view, FIG. 4 is a right side view, FIG. 5 is a left side view, FIG. 6 is a plan view and FIG. 7 is a back view. FIGS. 8 to  10  are perspective view of the process cartridge B, where FIG. 8 is a perspective view looked at from a front oblique direction, FIG. 9 is a perspective view looked at from a rear oblique direction, and FIG. 10 is a perspective view looked at from a rear oblique direction, with a bottom surface reversed to face upwardly. 
     As shown in FIG. 2, in the electrifying unit C, the electrifying roller  8   a,  regulating blade  8   c  and conductive brush  11  are integrated by the electrifying frame  13 . As shown in FIGS. 2,  4 ,  8 ,  9  and  10 , the electrifying frame  13  forms a part of an outer frame of the process cartridge B. As shown in FIGS. 2 and 10, a lower edge  13   a  of the electrifying frame  13  is disposed closely adjacent to the photosensitive drum  7  to define a gap therebetween and in parallel with the photosensitive drum  7 . A vertical wall  13   b  constituting a part of the outer frame of the process cartridge B extends from the lower edge  13   a  substantially vertically and is curved at an upper part to define a corner  13   c . A top plate portion  13   d  extends from the corner  13   c  substantially horizontally and has a substantially key-shaped cross-section, and, a space is defined below the top plate portion  13   d,  and member attaching portions  13   e,    13   f  (FIG. 8) are integrally formed with the vertical wall  13   b  at both longitudinal ends. 
     FIG. 11 is a side view looked at from the interior of the electrifying unit C. At a front side one end of the electrifying unit  13  in a mounting direction of the process cartridge B (the process cartridge is mounted to the main body  14  from a front side in the longitudinal direction), an electrifying roller bearing  22  and an end cover  24  are secured by screws. Further, a gear unit  24  is secured to the other end by screws. 
     FIG. 12 is a side view of the electrifying unit C with regulating blade  8   c  and support metal plate  8   d  omitted. As shown in FIG. 12, each blade attachement seat portions  13   g  raised from the member attachement portions  13   e,    13   f  via steps is provided with a female threaded portion  13   h  and a dowel  13   i  in a surface contacted with the regulating blade  8   c.  A longitudinal seal member  21   a  such as sponge is adhered to a surface retarded from the seat portions  13   g . Further, seal members  21   b  such as felt for preventing the developer from leaking axially outwardly are adhered to seal portions  8   a   1  at both ends of the electrifying roller  8   a  along a circumferential direction. Accordingly, portions of the electrifying frame  13  opposed to the seal portions  8   a   1  at both ends of the electrifying roller  8   a  are arcuate surfaces coaxial with the electrifying roller  8   a.    
     As shown in FIG. 2, the metallic regulating blade  8   c  is spaced apart from the electrifying roller  8   a  and is secured to the support metal plate  8   d  by small screws  8   j.  The support metal plate  8   d  has a groove-shaped section and is fitted onto the dowels  13   i  of the seat portions  13   g  of the electrifying frame  13 . Further, the support metal plate  8   d  abuts against the seat portions  13   g  by threading small screws  8   k  into the female threaded portions  13   h  of the seat portions  13   g  through holes formed in the support metal plate  8   d  and the seal member  21   a  is compressed by the support metal plate  8   d.  Further, the seal members  21   b  near the seat portions  13   g  are compressed by the support metal plate  8   d.  The support metal plate  8   d  has very high rigidity, and the electrifying frame  13  is reinforced by securing the support metal plate to the electrifying frame  13 . 
     (Mounting of electrifying unit) 
     The electrifying unit C is supported by the developing frame  12  for swinging movement around a swing center SC shown in FIG.  2 . To this end, as shown in FIG. 11, a gear case  26  of a gear unit  24  secured to a longitudinal rear side of the electrifying frame  13  is provided with a cylindrical shaft portion  26   a  centered on the swing center SC, and an end cover  23  at the other longitudinal end is provided with a hole  23   a  centered on the swing center SC. 
     As shown in FIG. 2, the developing frame  12  has a lower portion  12   f  adapted to contain the agitating screws  10   g,    10   h  at both sides of the partition wall  10   f  and having a seat portion  12   e  to which the regulating blade  10   e  is attached, a side portion  12   g  forming a left side outer frame of the process cartridge B looked at from the mounting direction, and end plate portions  12   h  (that side) and  12   i  (this side) on both longitudinal ends as shown in FIGS. 13,  14  and  17 . One end plate portion  12   h  is provided with a hole  12   j  for rotatably supporting the cylindrical shaft portion  26   a  of the electrifying unit C via a bearing. The other end plate portion  12   i  is provided with a hole  12   m  having the same diameter as that of the  23   a  of the electrifying frame  13 . In a condition that the cylindrical shaft portion  26   a  of the electrifying unit C is inserted into the hole  12   j  of the end plate portion  12   h  of the developing frame  12 , the cylindrical fitting hole  23  of the electrifying unit C is aligned with the hole  12   m  of the end plate portion  12   i  of the developing frame  12 . When the rear cover  17  at that side looked at from the mounting direction of the process cartridge B is aligned to coincide with the end of the developing frame  13 , an outer periphery of a hollow cylindrical shaft support portion  17   a  (FIGS. 11 and 15) protruded in the longitudinal direction in the inside of the rear cover  17  is fitted into the hole  12   j  of the developing frame  12  and at the same time an inner periphery of the shaft support portion is fitted onto the cylindrical shaft portion  26   a  of the electrifying unit C. Further, a support shaft  27  (FIGS. 11 and 14) fitted in the hole  12   m  of the end plate portion  12   i  of the developing frame  12  and protruded therefrom is fitted into the hole  23   a  of the electrifying unit C. In this way, in the electrifying unit C, the cylindrical shaft portion  26   a  is rotatably supported by the end cover  17  at one end and the hole  23   a  is rotatably supported by the developing frame  12  at the other end. 
     As shown in FIGS. 6 and 8, at an upper part of the developing frame  12 , a top plate  29  is secured to the developing frame  12  by small screws  28  while abutting against inside of an upper guide portion  12   a  of the side plate  12   g  and the end plate portions  12   h,    12   i.    
     As shown in FIG. 2, two spring seats  29   a  are provided on the top plate  29  along a longitudinal direction. Compression coil springs  30  held in the spring seats  29   a  are compressed between the top plate  29  and the electrifying frame  13 . By spring forces of the springs  30 , the electrifying unit C is biased in a clockwise direction in FIG. 2 around the swing center SC. 
     As shown in FIG. 11, spacer rollers  8   n  are rotatably fitted on reduced diameter journal portions  8   a   2  at both ends of the electrifying roller  8   a.  The spacer rollers  8   a  abut against a nonimage are of the photosensitive drum  7  by the spring force of the compression coil springs  30 . With this arrangement, the gap is defined between the photosensitive drum  7  and the electrifying roller  8   a,  so that the residual toner trying to pass through the gap between the electrifying roller  8   a  and the photosensitive drum  7  is caught by shifting the peripheral surface of the electrifying roller  8   a  in the direction opposite to the shifting direction of the peripheral surface of the photosensitive drum  7  and by applying the electrifying bias to the electrifying roller  8   a.    
     In the above description, a line connecting between the swing center and a center of the electrifying roller  8   a  is substantially perpendicular to a line connecting between the centers of the electrifying roller  8   a  and of the photosensitive drum  7 . 
     As shown in FIG. 2, the developing sleeve  10   d  is rockably attached to the developing frame  12  for swinging movement around a pressurizing center SLv. As shown in FIG. 17, spacer rollers  10   j  having a radius greater than that of the developing sleeve  10   d  by an amount corresponding to the developing gap are fitted onto reduced diameter journal portions  10   d   1  at both ends of the developing sleeve  10   d.  Swing arms  32  into which the journal portions  10   d   1  are fitted are provided outside of the spacer rollers  10   j.    
     FIG. 18 is a sectional view showing a side surface of the swing arm  32  and therearound in a plane perpendicular to the developing sleeve  10   d.  Proximal ends of the swing arms  32  are rockably supported on support shafts  33  press-fitted in the both end plate portions  12   h,    12   i  of the developing frame  12  in the longitudinal direction. The swing arm  32  is provided with a bearing hole  32   a  substantially above the support shaft  33  and a stopper portion  32   b  above the bearing hole. A spring seat  32   c  is provided on a line substantially perpendicular to a line connecting between the pressurizing center SLv and a center of the bearing hole  32   a.    
     The both end journal portions  10   d   1  of the developing sleeve  10   d  are rotatably supported in the bearing holes  32   a  of the swing arms  32 . Compression coil springs  35  are compressed between the spring seats  32   c  and spring seats  12   n  provided on the end plate portions  12   h,    12   i  of the developing frame  12 . With this arrangement, the developing sleeve  10   d  is rotated and pressurized around the pressurizing center SLv toward the photosensitive drum  7 , so that the spacer rollers  10   j  abut against the nonimage area of the photosensitive drum  7 , thereby maintaining a predetermined gap (0.2 to 1.0 mm) between the developing sleeve  10   d  and the photosensitive drum  7 . 
     During assembling/disassembling, the stopper portions  32   b  abut against a developing sleeve cover  36 , thereby preventing the swing arms  32  from rotating outwardly in FIG.  18 . Accordingly, in the assembled condition of the process cartridge B, the stoppers  32   b  do not abut against the developing sleeve cover  36 . Incidentally, the developing sleeve cover  36  extends between the both side swing arms  32  along the longitudinal direction and is secured to the developing frame  12  by screws. 
     (Mounting/dismounting construction of process cartridge) with respect to main body of image forming apparatus) 
     As shown in FIGS. 3 and 7 etc., flange-shaped guide portions  12   a ,  29   b  are provided on an upper part of the process cartridge at left and right looked at from the mounting/dismounting direction, and the guide portions  12   a ,  29   b  are engaged by guide rails (not shown) perpendicular to the plane of FIG. 1 during mounting and dismounting of the process cartridge with respect to the main body  14  of the image forming apparatus. 
     When the process cartridge B is mounted to the main body  14  of the image forming apparatus, contacts provided on the process cartridge are connected to contacts of the main body communicated with a high voltage power supply (not shown) provided on to the main body  14  of the image forming apparatus. 
     As shown in FIGS. 3 and 8, a drum grounding contact  101  communicated with the photosensitive drum  7  is provided at this side looked at from the mounting direction of the process cartridge B. Further, as shown in FIGS. 7,  9  and  10 , a conductive brush contact  102  communicated with the conductive brush  11 , an electrifying bias contact  103  communicated with the electrifying roller  8   a  and a developing bias contact  104  communicated with the developing sleeve  10   d  are provided at that side looked at from the mounting direction of the process cartridge B. 
     Three driving force receiving portions as shaft couplings rotated around a longitudinal shaft are provided on an end face at that side looked at from the mounting direction of the process cartridge B. When the process cartridge B is mounted to the main body  14  of the apparatus, the three driving force receiving portions are connected to driving members of the main body  14  of the apparatus. 
     As shown in FIG. 7, a coupling convex portion  37   d,  an electrifying portion coupling  38  and a developing portion coupling  39  as drum couplings are faced outwardly and located at positions retarded from the end face at that side of the process cartridge B. 
     As shown in FIG. 19, one end of the drum grounding contact  101  attached to the end plate portion  12   i  of the developing frame  12  is elastically contacted with a drum shaft  42 . The drum grounding contact  101  is provided on the developing frame  12  and has the other end protruded from the process cartridge B to form an external contact. 
     In the assembling, a pin  43  can axially pass through a groove  12   c  provided radially from a drum shaft support hole  12   b  of the end plate portion  12   i.    
     A driving side drum flange  37  is provided with, in order in an axial direction, an attachment portion  37   a  fitted into a drum cylinder  7   a,  a flange  37   b  contacted with an end of the drum cylinder  37   a,  a journal portion  37   c  having a diameter smaller than that of the flange  37   b,  and a coupling convex portion  37   d  convex axially from an end face center of the journal portion  37   c . The driving side drum flange  37  is a plastic one-piece formed by molding. 
     The journal portion  37   c  is rotatably fitted onto a shaft support portion  17   a  integrally formed with the rear cover  17  and fitted into the hole  12   d  of the end plate portion  12   h  of the developing frame  12  via a collar  56 . 
     As shown in FIG. 20, the coupling convex portion  37   d  is a twisted regular triangular prism centered on the drum shaft  42 . A diameter of a circumscribed circle of the triangular prism is smaller than that of the journal portion  37   c.    
     A driving device provided in the main body  14  of the apparatus includes a fixed motor  45 , a pinion  46  secured to a motor shaft of the motor  45 , a rotatably supported intermediate gear  47  meshed with the pinion  46  and a large gear  48 , the large gear  48 , a large gear shaft  49  secured to the large gear  48  and having a centering portion  57  at its end, a bearing  51  supporting the large gear shaft  49 , and a coupling concave shaft  52 . However, the intermediate gear  47  may be a plural-stage gear. 
     The bearing  51  supports the large gear shaft  49  not to shift the latter in the axial direction. A coupling concave portion  52   a  has a twisted regular triangular hole which can be engaged and disengaged with respect to the coupling convex portion  37   d  in the axial direction. When the coupling convex portion  37   d  is engaged by the coupling concave portion  52   a,  edge lines of the twisted regular triangular prism of the coupling convex portion  37   d  are contacted with faces of the twisted regular triangular hole of the coupling concave portion  52   a,  thereby aligning them with each other. The centering portion  57  and the coupling concave portion  52   a  have minute circumferential plays. In this connection, the coupling concave shaft  52  is positioned at a position where it is most shifted toward the process cartridge B, and is supported for retarding movement in opposition to a spring force (detailed explanation will be omitted). 
     A support portion of a nondriving side of the drum shaft  42  is designed so that the drum shaft  42  cannot be shifted toward the other driving side. As shown, a shaft stop ring  53  is fitted on the drum shaft  42 . A bearing  55  contained in the bearing case  54  secured to the front cover  16  secured to the end plate portion  12   i  of the developing frame  12  is fitted on the drum shaft  42  and is prevented from being shifted toward the other driving side of the drum shaft  42  by contacting the shaft stop ring  53  with the bearing case  54  with the interposition of the bearing  55 . On the other hand, in the photosensitive drum  7 , the shifting movement of the drum flange  37  toward the driving side is limited by the collar  56  fitted onto the journal portion  37   c.  In this arrangement, in order to permit the limited axial movement of the photosensitive drum  7 , a distance between the shaft support portion  17   a  and the bearing  55  is selected to be greater than a distance between a surface of the shaft stop ring  53  facing to the shaft support portion  17   a  and a surface of the collar  56  facing to the bearing  55 . 
     Since the driving device is constituted as mentioned above, when the process cartridge B is mounted to the main body  14  of the image forming apparatus, the longitudinal position of the cartridge frame (developing frame  12 , front cover  16  and rear cover  17 ) with respect to the main body  14  of the apparatus is determined. A distal end portion  42   a  of the drum shaft  42  is fitted into a hole  57   a  of the centering portion  57  and the coupling convex portion  37   d  is fitted into the coupling concave portion  52   a.  When the motor  45  is rotated, the pinion  46 , intermediate gear  47  and large gear  48  are rotated, with the result that the coupling concave shaft  52  is rotated via the large gear shaft  49  and the centering portion  57 . This rotation causes the coupling convex portion  37   d  and the coupling concave portion  52   a  to twist each other in the fitting direction. As a result, since the drum flange  37  and the coupling concave shaft  52  are pulled toward each other, the distal end of the coupling convex portion  37   d  is contacted with the bottom of the coupling concave portion  52   a.  Thus, the axial position of the photosensitive drum  7  is determined with respect to the positioned coupling concave shaft  52 . 
     When the process cartridge B is mounted to the main body  14  of the apparatus, if the coupling convex portion  37   d  is not fitted into the coupling concave portion  52   a,  the end face of the coupling convex portion  37   d  pushes an edge of the mouth of the concave portion  52   a  of the coupling concave shaft  52 , thereby retarding the coupling concave shaft  52  in opposition to the spring force biasing toward the process cartridge B. Accordingly, after the process cartridge B is mounted, during prerotation, when the phase of the coupling convex portion  37   d  is matched with the phase of the coupling concave portion  52   a,  these are automatically fitted with each other. Incidentally, in this connection, the end face of the coupling convex portion  37   d  may not abut against the bottom of the coupling concave portion  52   a,  but the flange  37   b  of the drum flange  37  may be pulled toward the shaft support portion  17   a  of the rear cover  17  via the collar  56  by the coupling pull force. 
     In the illustrated embodiment, while an example that the developing means, electrifying means capable of collecting the toner and the photosensitive drum are assembled as the process cartridge was explained, the support structure of the photosensitive drum with respect to the cartridge frame and engagement/disengagement between the driving force receiving portion of the photosensitive drum and the driving member of the main body of the image forming apparatus can be applied to general process cartridges. 
     Here, the process cartridge means a structure in which the electrifying means, developing means or cleaning means and the electrophotographic photosensitive member are integrally incorporated as a cartridge unit which can detachably mountable to the main body of the image forming apparatus, or at least one of the electrifying means, developing means and cleaning means and the electrophotographic photosensitive member are integrally incorporated as a cartridge unit which can detachably mountable to the main body of the image forming apparatus, or at least the developing means and the electrophotographic photosensitive member are integrally incorporated as a cartridge unit which can detachably mountable to the main body of the image forming apparatus. 
     (Driving of developing sleeve) 
     As shown in FIG. 17, a developing sleeve gear  15   b  is secured to the developing sleeve  10   d  outwardly of the journal portion  10   d   1  in the longitudinal direction. As shown in FIGS. 7,  13  and  21 , the developing sleeve gear  15   b  is meshed with a developing portion driving gear  15   a.  The developing portion driving gear  15   a  is formed integrally with a developing portion coupling  39  as a rotational driving force receiving portion and has a cylindrical hole at a center of that side of the developing coupling  39 . The cylindrical hole of the developing coupling  39  with the developing portion driving gear  15   a  is rotatably fitted on a longitudinal shaft portion (not shown) provided on the end plate portion  12   h  of the developing frame  12 . 
     The developing portion driving gear  15   a  is meshed with a small gear  15   c   1  of a two-stage gear  15   c . The two-stage gear  15   c  is fitted onto a longitudinal shaft portion  12   p  integrally provided on the end plate portion  12   h.  A large gear  15   c   2  of the two-stage gear  15   c  is meshed with an agitating gear  15   d  connected to a rear shaft end of the agitating screw  10   g  shown in FIG.  2 . The agitating gear  15   d  is meshed with an agitating gear  15   e  connected to a rear shaft end of the agitating screw  10   h.  The agitating gears  15   d,    15   e  have journals (not shown) intermediate in the axial direction and integrally have connecting portions (not shown) for connection to the agitating screws  10   g,    10   h  at distal ends thereof, so that the journals are rotatably received and supported by bearing holes (not shown) of the end plate portion  12   h  of the developing frame  12  and the connecting portions are engaged by rear ends of the agitating screws  10   h,    10   g  to drive the agitating screws  10   g,    10   h.  Incidentally, bearings for supporting the agitating gears  15   d,    15   e  will be described later. 
     Incidentally, front shaft ends of the agitating screws  10   g,    10   h  have holes, so that, as shown in FIG. 14, the shaft ends are press-fitted into longitudinal holes of the end plate portion  12   i  opposite to the end plate portion  12   h  of the developing frame  12  and the holes of the shaft ends is rotatably fitted onto support shaft  19   g,    19   h  protruded within the developing frame  12 . 
     In the condition that the process cartridge B is mounted to the main body  14  of the apparatus, when the driving force is transmitted from the main body  14  of the apparatus, the developing portion coupling  39  is rotated. The developing portion driving gear  15   a  integral with the developing portion coupling  39  rotates the developing sleeve gear  15   b,  thereby rotating the developing sleeve  10   d.  Further, the developing portion driving gear  15   a  drives the agitating gear  15   d  via the two-stage gear  15   c , and the agitating gear  15   d  transmits the rotation to the agitating gear  15   e.  As a result, the agitating screws  10   g,    10   h  are rotated to agitate the toner while circulating the toner. 
     The developing sleeve  10   d  is rotated in the same direction as the photosensitive drum  7 . Thus, at the opposed area (developing area) between the developing sleeve  10   d  and the photosensitive drum  7 , the peripheral surface of the developing sleeve  10   d  is shifted in a direction opposite to a shifting direction of the peripheral surface of the photosensitive drum  7 . The spacer rollers  10   j  (FIG. 17) rotatably supported on both ends of the developing sleeve  10   d  are rollingly rotated together with the photosensitive drum  7  and are rotated in a direction opposite to the rotating direction of the developing sleeve  10   d.    
     As shown in FIG. 21, the gears  15   a ,  15   b,    15   c ,  15   d,    15   e  are covered by the rear cover  17  contacted with and secured to the end plate portion  12   h  of the developing frame  12 . 
     (Support and driving structure of agitating members) 
     In the illustrated embodiment, since the agitating gears  15   d  and  15   e  are identical, only the agitating gear  15   d  will be explained. As shown in FIGS. 22 and 24, the agitating gear  15   d  has a toothed portion  15   d   1  and a journal portion  15   d   2 . The journal portion  15   d   2  is provided at its distal end with a coupling hole  15   d   3  into which a shaft end  10   g   1  of the agitating screw  10   g  is fitted. The hole  15   d   3  is a cylindrical hole having a mouth centered on the journal portion  15   d   2 , and the bottom of the cylindrical hole is a D-cut shaped hole  15   d   5  having the same diameter as that of the cylindrical hole. A length of the journal portion  15   d   2  is substantially the same as a length from an outer end of a bearing house  12   r  provided outside of the developing frame  12  to an inner face  12   s  of the developing frame  12 . 
     As shown in FIG. 23, the bearing  58  as the bearing member has a small diameter hole  58   b  corresponding to an inner diameter of an inner cylinder  58   i  of an outer/inner double cylinder, and a large diameter hole  58   a  contiguous with the small diameter hole  58   b  and directing toward the interior of the developing frame  12  and having a diameter greater than the diameter of the small diameter hole  58   b.  The small diameter hole  58   b  of the bearing  58  serves to slidingly receive the journal portion  15   d   2 . The large diameter hole  58   a  is a seal member attaching hole into which a seal member  59  is press-fitted, and this portion has a single cylindrical shape. 
     An outer diameter of the bearing  58  is substantially cylindrical. A length of the bearing  58  is equal to a length L of the developing frame  12 . A D-cut portion  58   d  is provided on an axial end of the bearing  58  and directing toward the interior of the developing frame  12 . 
     A D-cut hole portion  12   q   1  having the same section and same axial width as those of the D-cut portion  58   d  and facing toward the interior of the developing frame  12  is provided in a hole  12   q  as a substantially cylindrical through-hole positioned at the center of the bearing house  12   r  to just receive the D-cut portion  58   d.    
     A cantilever support member  58   c  is provided on an outer periphery of the bearing  58  at a position opposite to the D-cut portion  58   d  in circumferential and axial directions. As shown in FIG. 25, there are two slits  58   p  parallel with a generating line of an outer cylinder  50   o,  and the cantilever support member  58   c  is defined between the slits  58   p.  The cantilever support member  58   c  is positioned on an extension of the outer periphery of the outer cylinder  58   o  except for a distal end. The distal end  58   p   1  of the cantilever support member  58   c  is protruded from the outer periphery of the outer cylinder  58   o  radially outwardly. In an assembled condition, the distal end protrusion  58   p   1  is fitted into a small hole  12   q   2  formed in the hole  12   q  of the bearing house  12   r.  The small hole  12   q   2  may pass through the bearing house  12   r  in the radial direction. 
     An shaft end  10   g   1  of the agitating screw  10   g  provided as the agitating member in the illustrated embodiment has a cylindrical proximal portion  10   g   2  fitted into a cylindrical portion  15   d   4  of the coupling hole  15   d   3  of the agitating gear  15   d,  and a D-cut shaft portion  10   g   3  just fitted into the D-cut hole  15   d   5 . 
     For example, an oil seal may be used as the seal member  59 , and a lip has a dimension that it can penetrate into the journal portion  15   d   2 . 
     In this connection, when the gear portion  15   d   1  is rotated by the driving force, the agitating screw  10   g  is rotated. The seal member  59  serves to seal the toner within the developing frame  12 . 
     The agitating screw  10   h  is supported and driven in the same manner as mentioned above. 
     (Assembling Method of Agitating Member) 
     When the seal member  59  is attached to the bearing  58 , as shown in FIGS. 22 and 23, the seal member  59  is shifted up to that side of the large diameter hole  58   a  and is urged against a step between the large diameter hole  58   a  and the small diameter hole  58   b . The outer diameter of the seal member  59  is reduced by the large diameter hole  58   a , as shown by the two-dot and chain line in FIG.  24 . Here, journal  15   d   2  of the agitating gear  15   d  is fitted into the inner cylinder  58   i  of the bearing  58 . In this case, due to the outer diameter of the journal portion  15   d   2  of the agitating gear  15   d  (or  15   e ), the inner diameter of the seal member  59  is assembled in a slightly compressed condition. As a result, the toner is prevented from leaking between the bearing  58  and the agitating gear  15   d  (or  15   e ). In a condition that the seal member  59  and the agitating gear  15   d  are assembled in this way, the bearings  58  are assembled into the both end through-holes  12   q  of the developing frame  12  from outside, thereby connecting the agitating gears  15   d ,  15   e  to the agitating screws  10   g,    10   h.  The large diameter hole  58   a , small diameter hole  58   b  and through holes  12   q  of the developing frame  12  are coaxial. 
     In this case, as shown in FIGS. 23 and 24, the bearing  58  has the cantilever support member  58   c  and the D-cut portion  58   d  and is fixedly supported by the developing frame  12  so that the bearing is not rotated by the longitudinal positioning and the rotation of the agitating gear  15   d  (or  15   e ) connected to the agitating screws  10   g  (or  10   h ). Further, the bearing  58  is fitted into the through-hole  12   q  of the developing frame  12  to prevent toner leakage. 
     Further, explaining in detail, the bearing  58  to which the agitating gear  15   d  and the seal member  59  were assembled is positioned and prevented from being shifted toward the interior of the developing frame  12  by fitting the D-cut portion  58   d  into the D-cut hole  12   q   1  of the bearing house  12   r.  At the same time, the fitting between the D-cut portion  58   d  and the D-cut hole  12   q   1  provides the positioning of the bearing  58  and prevention of rotation of the bearing with respect to the hole  12   q  of the bearing house  12   r  in the circumferential direction. 
     Further, at a last stage of insertion of the bearing  58  into the hole  12   q , an inclined introduction portion  58   p   2  of the protrusion  58   p   1  is pushed by the edge of the inlet of the hole  12   q  to shift the distal end protrusion  58   p   1  of the cantilever support member  58   c  toward the center of the bearing  58 . When the protrusion  58   p   1  enters into the hole  12   q  and reaches the small hole  12   q   2 , the protrusion is restored by the elastic force of the cantilever support member  58   c  to be inserted into the small hole  12   q   2 . As a result, the bearing  58  cannot be shifted so long as any tool is not used. 
     Similar to the assembling, in the disassembling, the bearing  58  is removed together with the agitating gear  15   d  and the seal member  59 . In the illustrated embodiment, a disassembling tool is a specific tool. If the small hole  12   q   2  is a through-hole or if the agitating gear  14   d  is provided with an axial through-hole which can face to the cantilever support member  58   c,  a driver is used. In FIG. 24, the removal of the bearing is effected by pushing the distal end protrusion  58   p   1  of the cantilever support member  58   c  toward the radial direction center of the bearing  58  and by removing the protrusion  58   p   1  from the small hole  12   q   2  and by pulling the agitating gear  15   d  outwardly of the developing frame  12  in the axial direction. 
     In this way, the bearing can be removed together with the agitating gear  15   d  and the seal member  59 . 
     Further, a diameter of the vane (spiral portion) of the agitating screw is selected to be smaller than the through-hole  12   q  of the developing frame  12 , so that, in a condition that the bearing  58  is removed from the through-hole  12   q , the agitating screw  19   g  can be removed through the through-hole  12   q . Thus, the maintenance and recycle of the developing device can be facilitated. 
     Further, in place of the bearing  58  shown in FIG. 23, a bearing as shown in FIG. 26 may be used. 
     The bearing shown in FIG. 26 has a hole  58   r  having a diameter slightly smaller than the diameter of the shaft end  10   g   1  of the agitating screw  10   g . A seal member  59  having a hole coaxial with the hole  58   r  is mounted on a bottom surface  58   t  of a large diameter hole  58   s  of the bearing  58  from the agitating gear  15   d  side. FIG. 27 shows a condition that the bearing on which the agitating screw  10   g  and the seal member  59  are mounted, and the agitating gear  15   d  are attached to the developing device. 
     Also with this arrangement, the bearing can be mounted and dismounted together with the agitating gear and the seal member with respect to the frame  12  of the developing device. Further, the agitating screw  10   g  can be removed through the through-hole  12   q.    
     In the illustrated embodiment, while the process cartridge of so-called cleaner-less type was explained, the present invention can, of course, be applied to a process cartridge having cleaning means. 
     As mentioned above, according to the present invention, since the assembling ability for the bearing member, drive transmitting member and agitating member is enhanced and the bearing member can be removed from the developing apparatus, the cleaning of the through-hole of the bearing, exchanging of the seal member (if provided) and exchanging the agitating member can be facilitated. 
     The present invention is not limited to the above-mentioned embodiments, but various alterations and modifications can be made within the scope of the invention.