PATENT DOCUMENT

Abstract:
An electrical contact member for electrically connecting to an external contact which is electrically connected with an electroconductive cylindrical member having a photosensitive layer on an outer surface thereof and which is provided outside the cylindrical member, the electrical contact member comprising a first contact portion contacted with the cylindrical member; a second contact portion contacted with the external contact; a first extension connected electrically with the first contact portion and extending in a diametrical direction across an axis of the cylindrical member; and a second extension electrically connecting with the first extension and extending the diametrical direction toward the axis, the second extension being provided with the second contact portion, wherein when second contact portion is contacted by the external contact, second contact portion displaces along the axis.

Full Description:
FIELD OF THE INVENTION AND RELATED ART 
       [0001]    The present invention relates to an electrical connector, an electrophotographic photosensitive drum, and a process cartridge having an electrophotographic photosensitive drum. 
         [0002]    An electrophotographic image forming apparatus to which the present invention relates is an apparatus which forms an image on recording medium (ordinary paper, OHP sheet, and the like, for example) with the use of an electrophotographic image formation method. Examples of an electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (laser beam printer, LED printer, and the like, for example), and a facsimile machine. 
         [0003]    A process cartridge to which the present invention relates is a cartridge in which an electrophotographic photosensitive drum, and at least one processing means, more specifically, a charging means, a developing means, or a cleaning means, are integrally contained, and which is removably mountable in the main assembly of an electrophotographic image forming apparatus. 
         [0004]    An electrophotographic image forming apparatus has been known to have an electrophotographic photosensitive drum, and one or more processing devices, such as a charging device, an exposing device, a cleaning device, etc., which are in the adjacencies of the peripheral surface of the photosensitive drum. Further, an electrophotographic photosensitive drum has been known to be structured to release its residual charge to the main assembly of an image forming apparatus. One of the inventions related to the structural arrangement for this technology is disclosed in Japanese Laid-open Patent Application H06-083123. 
         [0005]    The image forming apparatus disclosed in Japanese Laid-open Patent Application H06-08123 has an electrophotographic photosensitive drum, which is made up of an electrically conductive cylindrical member (drum), and an electrophotographic photosensitive layer which covers the peripheral surface of the cylindrical member. The electrically conductive cylinder, which hereafter may be referred to simply as a photosensitive drum, has a pair of flanges, which are immovably fitted in the openings of the lengthwise ends of the photosensitive drum, one for one, by being pressed into the openings. Each flange has a shaft-like portion, by which the photosensitive drum is rotationally supported, or a hole through which a shaft for supporting the photosensitive drum is put. Further, one of the flanges is fitted with an electrically conductive member, that is, an electrical connector, which has the first and second portions of contact. The first portion of contact contacts the inward surface of the photosensitive drum, whereas the second portion of contact is electrically in contact with the external electrical connector of a process cartridge, or the main assembly of an electrophotographic image forming apparatus. 
         [0006]    It is assumed here that a process cartridge is structured so that a photosensitive drum is supported by an electrically conductive shaft (drum shaft) which is solidly attached to the frame (shell) of the process cartridge and functions as the abovementioned external electrical connector. In the case of the electrophotographic image forming apparatus disclosed in Japanese Laid-open Patent Application H06-083123, the electrical connector is in the form of a leaf spring, and the second portion of contact of the electrical connector is kept in contact with the inward end of the drum shaft with the application of a present amount of pressure to maintain electrical connection between the electrical connector and drum shaft. 
         [0007]    In recent years, however, this setup has become problematic because of the increase in the desire for a small electrophotographic image forming apparatus. In order to reduce an electrophotographic image forming apparatus in size, an electrophotographic image forming apparatus has to be reduced in the size of its main assembly, which in turn requires a process cartridge to be reduced in size. In order to reduce a process cartridge in size, a photosensitive drum, in the adjacencies of which the processing means are placed, has to be reduced in size. In recent years, therefore, a photosensitive drum has been reduced in size, more specifically, in diameter. In order to ensure electrical connection is maintained between the portion (point) of contact of the electrical connector and the end of the shaft of the photosensitive drum, the contact pressure between the portion of contact of the electrical connector and the end of the shaft of the photosensitive drum has to be greater than a certain amount, that is; it cannot be excessively low. Thus, the aforementioned conventional structural arrangement for electrical connection has become problematic for the following reason. That is, with the reduction in the diameter of the cylindrical member of a photosensitive drum, it became difficult to provide an electrical connector for a photosensitive drum, which is structured like the aforementioned conventional electrical connector, and yet, is placeable in a small place, unlikely to suffer from plastic deformation, and stable in electrical connection. Thus, it is necessary to come up with an innovative design for an electrical connection for an electrophotographic photosensitive drum, which makes it possible to place the electrical connector in a smaller space than the space that used to be afforded, and yet, can keep the electrical connector stable in the electrical connection between the electrical connector and the external electrical connector even if the point of contact between the electrical connector and external electrical connector shift in position. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is one of the results of the improvement of an electrical connector such as those described above. Thus, the primary object of the, present invention is to provide an electrical connector for an electrophotographic photosensitive drum, which is stable in the contact pressure between itself and an external electrical connector, and yet, can be placed inside even the cylindrical member of an electrophotographic photosensitive member, which is significantly smaller in diameter than the cylindrical member of a conventional electrophotographic photosensitive drum. 
         [0009]    According to an aspect of the present invention, there is provided an electrical contact member for electrically connecting to an external contact which is electrically connected with an electroconductive cylindrical member having a photosensitive layer on an outer surface thereof and which is provided outside the cylindrical member, said electrical contact member comprising a first contact portion contacted with said cylindrical member; a second contact portion contacted with said external contact; a first extension connected electrically with said first contact portion and extending in a diametrical direction across an axis of said cylindrical member; and a second extension electrically connecting with said first extension and extending in the diametrical direction toward the axis, said second extension being provided with said second contact portion, wherein when second contact portion is contacted by the external contact, second contact portion displaces along the axis. 
         [0010]    According to another aspect of the present invention, there is provided an electrophotographic photosensitive drum usable with an electrophotographic image forming apparatus, said electrophotographic photosensitive drum comprising (i) an electroconductive cylindrical member having a photosensitive layer on an outer surface thereof; (ii) an electrical contact member electrically connected with said cylindrical member and electrically connected with an external contact outside said cylindrical member; a first contact portion contacted with said cylindrical member; a second contact portion contacted with said external contact; a first extension connected electrically with said first contact portion and extending in a diametrical direction across an axis of said cylindrical member; and a second extension electrically connecting with said first extension and extending in the diametrical direction toward the axis, said second extension being provided with said second contact portion, wherein when second contact portion is contacted by the external contact, second contact portion displaces along the axis. 
         [0011]    According to a further aspect of, the present invention, there is provided a process cartridge detachably mountable to an image forming apparatus, said process cartridge comprising an electrophotographic photosensitive drum including, (i) an electroconductive cylindrical member having a photosensitive layer on an outer surface thereof; (ii) an electrical contact member electrically connected with said cylindrical member and electrically connected with an external contact outside said cylindrical member; a first contact portion contacted with said cylindrical member; a second contact portion contacted with said external contact; a first extension connected electrically with said first contact portion and extending in a diametrical direction across an axis of said cylindrical member; and a second extension electrically connecting with said first extension and extending in the diametrical direction toward the axis, said second extension being provided with said second contact portion, wherein when second contact portion is contacted by the external contact, second contact portion displaces along the axis. 
         [0012]    These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a schematic sectional view of a typical image forming apparatus to which the present invention is applicable. It shows the general structure of the apparatus. 
           [0014]      FIG. 2  is a schematic sectional view of the process cartridge in accordance with the present invention. It shows the structure of the cartridge. 
           [0015]      FIG. 3  is an exploded perspective view of the process cartridge in accordance with the present invention. It shows the structure of the cartridge. 
           [0016]      FIG. 4  is a perspective view of the process cartridge in accordance with the present invention. It shows the structure of the cartridge. 
           [0017]      FIG. 5  is an exploded perspective view of one of the lengthwise end portions of the photosensitive drum, which has the electrical connector in the first preferred embodiment of the present invention. It shows the structure of the end portion. 
           [0018]      FIG. 6  is a drawing for describing the structure of one of the lengthwise end portions of the photosensitive drum in the first embodiment,  FIGS. 6(   a ),  6 ( b ),  6 ( c ) and  6 ( d ) being: a perspective view of the combination of the electrical connector, cylindrical member, and drum; a plan view of the combination of the electrical connector, cylindrical member, and flange; a sectional view of the combination of the electrical connector, cylindrical member, flange, and drum shaft, at a vertical plane which coincides with the axial line of the drum shaft; and a sectional view of the drum shaft, at a plane which coincides with the axial line of the drum shaft, respectively. 
           [0019]      FIG. 7  is a drawing for describing the structure of one of the lengthwise end portions of the photosensitive drum in the second embodiment,  FIGS. 7(   a ) and  7 ( b ) being: an exploded perspective of the lengthwise end portions of the photosensitive drum, which has the electrical connector; and a perspective view of the combination of the cylindrical member and the fastener portion of the electrical connector, respectively. 
           [0020]      FIG. 8  is a drawing for describing the structure of one of the lengthwise end portions of the photosensitive drum in the second embodiment,  FIGS. 8(   a ),  8 ( b ) and  8 ( c ) being: a perspective view of the combination of the electrical connector and drum; a plan view of the combination of the electrical connector and cylindrical member of the photosensitive drum; and a sectional view of the combination of the electrical connector, cylindrical member, and shaft of the photosensitive drum, at a vertical plane which coincides with the axial line of the shaft, respectively. 
           [0021]      FIG. 9  is a drawing for describing the structure of one of the lengthwise end portions of the photosensitive drum in the third embodiment,  FIGS. 9(   a ),  9 ( b ) and  9 ( c ) being: a perspective view of the combination of the electrical connector and drum shaft; a plan view of the combination of the electrical connector and cylindrical member of the photosensitive drum; and a sectional view of the combination of the electrical connector, cylindrical member, and drum shaft, at a vertical plane which coincides with the axial line of the shaft, respectively. 
           [0022]      FIG. 10  is a drawing for describing the structure of one of the lengthwise end portions of the photosensitive drum in the fourth embodiment,  FIGS. 10(   a ),  10 ( b ),  10 ( c ) and  10 ( d ) being: a perspective view of the combination of the electrical connector and drum shaft; a plan view of the combination of the electrical connector and cylindrical member; a sectional view of the combination of the electrical connector, cylindrical member, and drum shaft, at a vertical plane which coincides with the axial line of the drum shaft, respectively. 
           [0023]      FIG. 11  is a drawing for showing the structure of one of the lengthwise end portions of the photosensitive drum in the fifth preferred embodiment of the present invention,  FIGS. 11(   a ),  11 ( b ),  11 ( c ) and  11 ( d ) being a perspective, view the combination of the electrical connector, flange, and drum shaft; a sectional view of the combination of the electrical connector, cylindrical member, and flange, at a plane perpendicular to the axial line of the shaft; a sectional view of the combination of the electrical connector, cylindrical member, flange, and drum shaft, at a vertical plane which coincides with the axial line of the shaft; and a perspective view of the tip portion of the portion of contact of the electrical connector, respectively. 
           [0024]      FIG. 12  is a drawing for showing the structure of one of the lengthwise end portions of the photosensitive drum in the modified version of the fifth embodiment,  FIGS. 12(   a ),  12 ( b ),  12 ( c ) and  12 ( d ) being a perspective view of the combination of the electrical connector, flange, and drum shaft; a sectional view of the combination of the electrical connector, cylindrical member, and flange, at a plane perpendicular to the axial line of the cylindrical member; a sectional view of the combination of the electrical connector, cylindrical member, flange, and drum shaft, at a plane which coincides with the axial line of the drum shaft; and a perspective view of the tip portion of the portion of contact of the electrical connector, respectively. 
           [0025]      FIG. 13  is a drawing for showing the structure of one of the lengthwise end portion of the photosensitive drum in the sixth embodiment,  FIGS. 13(   a ),  13 ( b ),  13 ( c ) and  13 ( d ) being a perspective view of the combination of the electrical contact, flange, and drum shaft; a sectional view of the combination of the electrical connector, cylindrical member, and flange, at a plane perpendicular to the axial line of the cylindrical member; a sectional view of the combination of the electrical contact, cylindrical member, flange, and drum shaft, at a vertical plane which coincides with the axial line of the drum shaft, and a perspective view of the electrical contact; respectively. 
           [0026]      FIG. 14  is a drawing for showing the structure of one of the lengthwise ends of the photosensitive drum in the seventh embodiment,  FIGS. 14(   a ),  14 ( b ) and  14 ( c ) being a perspective view of the combination of the electrical connector, flange, and drum shaft; a sectional view of the combination of the electrical connector, cylindrical member, and the flange at a plane perpendicular to the axial line of the cylindrical member; and a sectional view of the combination of the electrical connector, cylindrical member, flange, and drum shaft, at a vertical plane which coincides with the axial line of the drum shaft, respectively. 
           [0027]      FIG. 15  is a drawing for showing the structure of one of the lengthwise end portions of the photosensitive drum in the eighth embodiment,  FIGS. 15(   a ),  15 ( b ),  15 ( c ),  15 ( d ) and  15 ( e ) being a perspective view of the combination of the electrical connector, flange, eternal electrical connector, and cartridge frame  71 ; a plan view of the combination of the electrical connector, cylindrical member, flange, and cartridge frame  71 ; a sectional view of the combination of the electrical connector, cylindrical member, flange, external electrical connector; and cartridge frame  71 , at a vertical plane which coincides with the axial line of the drum shaft; a perspective view of the electrical connector; and a perspective view of the electrical connector, respectively. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Hereinafter, the preferred embodiments of the present invention are described in detail with reference to the appended drawings. However, the measurement, material, and shape of each of the structural components of the electrophotographic image forming apparatuses in the preferred embodiments, and the positional relationship among the structural components, are not intended to limit the present invention in scope, unless specifically noted. That is, the present invention is also applicable to various modified versions of the electrophotographic image forming apparatuses and process cartridges therefore, which are modified in structure to accommodate various conditions under which they are operated. 
         [0029]      FIG. 1  is a sectional view of the image forming apparatus  100  in the first preferred embodiment of the present invention. It shows the general structure of the apparatus  100 . The image forming apparatus  100  is an image forming apparatus which uses an electrophotographic image formation process. As is evident from  FIG. 1 , the image forming apparatus  100  has the main assembly  100 A (which hereafter will be referred to as apparatus main assembly  100 A). The apparatus main assembly  100 A has an image formation station  52  where an image is formed. The image formation station  52  comprises an electrophotographic photosensitive drum  7  (which hereafter will be referred to simply as “photosensitive drum”) as an image bearing member, and a transfer roller  4  as an image transferring member, etc. 
         [0030]    The image forming operation performed by the image forming apparatus  100  is as follows: First, the photosensitive drum  7 , which is in the form of a drum and has a photosensitive layer, is charged by a charge roller  8  across its peripheral surface. Then, the charged portion of the peripheral surface of the photosensitive drum  7  is exposed to (scanned by) a beam of laser light projected from an optical system  1  while being modulated according to the information of the image to be formed. Thus, an electrostatic latent image, which reflects the information of the image to be formed, is formed on the peripheral surface of the photosensitive drum  7 . This electrostatic latent image is developed into a visible image formed of toner. More specifically, voltage is applied to a development roller  10   d,  as a developer bearing member, on which developer t is present. Consequently, the developer t transfers from the development roller  10   d  onto the photosensitive drum  7  in the pattern of the electrostatic latent image on the peripheral surface  7 . 
         [0031]    While the visible image is formed of the developer t on the peripheral surface of the photosensitive drum  7 , a sheet  2  of recording medium (ordinary paper, OHP sheet, and the like) is conveyed to the image formation station  52  from a cassette  3   a  in the direction indicated by an arrow mark E by a recording medium conveying device  3   b  (recording medium conveying means), while being guided by the first guiding plate  3   f   1 , in synchronism with the formation of the visible image of the developer t. Then, the image formed on the peripheral surface of the photosensitive drum  7  of the developer t is transferred on to the sheet  2  of recording medium in the image formation station  52  by the application of voltage to the transfer roller  4  as the image transferring means. The image formation station  52  is in a cartridge  10 , which is a process cartridge. 
         [0032]    After the transfer of the image formed of the developer t. (which hereafter may be referred to as developer image) onto the sheet  2  of recording medium, the sheet  2  is conveyed to the fixing device  5  as a fixing means while being guided by the second guiding plate  3   f   2 . The fixing device  5  has a driver roller  5   a,  a fixation roller  5   c,  and a heater  5   b  which is in the hollow of the fixation roller  5   c.  After being conveyed through the fixing device  5 , the sheet  2  is conveyed further by a pair of discharge roller  3   d,  and is discharged into the delivery tray  6  through the sheet turning path. Incidentally, the image forming apparatus  100  is provided with an unshown combination of a manual feed tray and a manual feed roller, making it possible for a user to manually feed the sheet  2  of recording medium into the apparatus main assembly  100 A. 
         [0033]      FIG. 2  is a sectional view of the cartridge  101 . It shows the structure of the cartridge  101 . As is evident from  FIG. 2 , the cartridge  101  has the photosensitive drum  7 , and a cleaning blade  17  for removing the developer remaining on the peripheral surface of the photosensitive drum  7 , that is, one of the processing means. 
         [0034]    In an image forming operation in which the cartridge  101  is used, the photosensitive drum  7  rotates in the direction indicated by an arrow mark R. As the photosensitive drum  7  rotates, its peripheral surface is uniformly charged by the charge roller  8  as a charging means. Then, the uniformly charged portion of the peripheral surface of the photosensitive drum  7  is exposed to (scanned by) a beam of the light projected from an optical system  1 , through the opening with which the cleaning means frame  11  is provided. As a result, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum  7 . Incidentally, the photosensitive drum  7  is supported by the cleaning means frame  11 . 
         [0035]    The developing device  10  is provided with a development roller  10   d,  which is rotatably supported by the frame of the developing device  10 . The developing device  10  is also provided with a development blade  10   e,  which is a developer regulating means. The development blade  10   e  is attached to the frame of the developing device  10  in such a manner that its tip portion is kept virtually in contact with the peripheral surface of the development roller  10   d.  Further, the developing device  10  is provided with a developer storage in which the developer t is stored to be delivered to the development roller  10   d.    
         [0036]    As the development roller  10   d  is rotated, the developer t in the developer storage is borne by the peripheral surface of the development roller  10   d,  and is regulated by the development blade  10   e,  whereby a layer of the developer t, which is uniform in thickness, is formed on the peripheral surface of the development roller  10   d.  Then, development bias is applied to the development roller  10   d,  whereby the developer t on the photosensitive drum  7  is transferred onto the peripheral surface of the photosensitive drum  7  in the pattern of the electrostatic latent image; the electrostatic latent image is developed into a visible image formed of the developer t. Then, the image formed of the developer t, that is, the visible image, is transferred onto the sheet  2  of recording medium by the application of transfer bias to the transfer roller  4  ( FIG. 1 ). 
         [0037]    After the transfer of the developer image onto the sheet  2 , the developer t remaining on the peripheral surface of the photosensitive drum  7  is removed by the cleaning blade  17  as a cleaning means. The removed developer is collected in the cleaning means container  31 . The cleaning means is provided with a sheet  51 , which captures the residual developer as the residual toner is separated from the peripheral surface of the photosensitive drum  7  by the cleaning blade  17 . The sheet  51  is on the upstream side of the cleaning blade  17  in terms of the rotational direction of the photosensitive drum  7 . It is attached to the cleaning means frame  31 . Further, the cleaning means is provided with a seal  11   d,  which is between the cleaning means container  31  and cleaning blade  17 , and prevents the residual developer from leaking from the cleaning means container  31  after being removed by the cleaning blade  17  and collected in the cleaning means container  31 . 
         [0038]    Further, the cleaning device  11  has a protective shutter  12  for protecting the photosensitive drum  7 . When the cartridge  101  is not in use, this protective shutter  12  remains in its protective position (unshown) in which it keeps the photosensitive drum  7  covered. As the cartridge  101  is mounted into the apparatus main assembly  100 A, the protective shutter  12  is moved into its exposure position in which it keeps the photosensitive drum  7  exposed from the cartridge  101 . That is, when the cartridge  101  is in use, the protective shutter  12  is in the exposure position. Thus, the cartridge  101  is structured so that the protective cover  12  can be rotationally moved between the protective position and exposure position. 
         [0039]      FIG. 3(   a ) is an exploded perspective view of the development unit and cleaning unit. It shows the structure of the cartridge  101  and drum shaft  61 .  FIG. 3(   b ) also is an exploded perspective view of the development unit and drum unit. It shows the structure of the cartridge  101  and external electrical connector  14 . As is evident from  FIGS. 3(   a ) and  3 ( b ), the cartridge  101  has the cleaning unit v as the first unit, and development unit u as the second unit, and drum holder  13 . The cleaning unit v has the cleaning means container  31 , photosensitive drum  7 , charge roller  8  and cleaning blade  17 . 
         [0040]    The development unit u has the frame  80  and development roller  10   d  ( FIG. 2 ). The frame  80  has the developer container  10  and a pair of end members  82  and  81 . The end members  82  and  81  are solidly attached to the lengthwise ends of the developer container  10 , one for one. The end member  82  rotationally supports the development roller  10   d  ( FIG. 2 ) in the development means container  10 , by one of the lengthwise ends of the development roller  10   d.  The end member  81  rotationally supports the development roller  10   d  ( FIG. 2 ) in the development means container  10 , by the other lengthwise end of the development roller  10   d.  The drum holder  13  is solidly attached to the cleaning device  11 . It rotationally holds the photosensitive drum  7  and charge roller  8 . 
         [0041]    Next, the structural arrangement for&#39;supporting the development unit u by the cleaning unit v is described. As described before, the development unit u has the end members  82  and  81 , which are attached to the lengthwise ends of the developing means container  10 , one for one. The end member  82  has an arm  82   a,  whereas the end member  81  has an arm  81   a.  The arms  82   a  and  81   a  point toward the cleaning unit v (and are perpendicular, to the lengthwise direction of development unit frame  10 ). Further, the end members  82  and  81  are provided with a pair of shafts  82   b  and  81   b,  by which the development unit u is in connection to the cleaning unit v. The shafts  82   b  and  81   b  are attached to the tip of the arm  82   a,  and the tip of the arm  81   a,  respectively. The shaft  82   b  and  81   b  in each of the preferred embodiments of the present invention are cylindrical. 
         [0042]    The photosensitive drum  7  has a cylindrical member  7   e  and an electrophotographic photosensitive layer. The cylindrical member  7   e  is made of an electrically conductive substance. The photosensitive layer covers the entirety of the peripheral surface of the cylindrical member  7   e.  The photosensitive drum  7  is provided with a drum gear  7   a  and a drum flange  42 , which are solidly attached to the lengthwise ends of the cylindrical member  7   e,  one for one, by having been pressed into the opening of the lengthwise ends of the cylindrical member  7   e.  The lengthwise end of the photosensitive drum  7 , which has the flange  42 , is structured to allow the residual charge of the photosensitive drum  7  to escape to the apparatus main assembly  100 A. The lengthwise end of the photosensitive drum  7 , which has the drum gear  7   a,  is provided with a driving force transmitting portion  7   c  (coupling) into which the force for driving the photosensitive drum  7  is inputted from the driving force outputting portion (unshown) of the apparatus main assembly  100 A. 
         [0043]    Further, the lengthwise ends of the cleaning device  11  are provided with drum supporting portions  11 A and  11 B, one for one. The lengthwise end of the photosensitive drum  7 , which has the drum flange  7   a,  is rotationally supported by a drum shaft  61  ( FIG. 3(   a )) or external electrical connector  14  ( FIG. 3(   b )), which is supported by the plate  11 A 1  of the drum supporting portion  11 A. The drum shaft  61  and external electrical connector  14  are solidly attached to the first guiding portion  11   f  of the drum supporting plate  11 A by having been pressed into the hole (unshown) of the guiding portion  11 F. The other lengthwise end of the photosensitive drum  7  is rotationally supported by the drum supporting portion  13   h  of the drum holder  13  attached to the supporting plate  11 B 1  of the drum supporting portion  11 B. That is, the cleaning device  11  rotatably holds one of the lengthwise ends of the photosensitive drum  7  by the drum supporting portion  11 A, and the other lengthwise end of the photosensitive drum  7  by the drum holder  13 . 
         [0044]    Further, the plate  11 A 1  of the drum supporting portion  11 A of the cleaning device  11  has a hole  11   e , and the drum holder  13  has a hole  13   c.  The aforementioned shaft  82   b  and  81   b  are in the holes lie and  13   c,  respectively, being thereby rotatably supported by the plate  11 A 1  of the drum supporting portion  11 A and the drum holder  13 , respectively. In other words, the development unit u is supported by the cleaning means container  31  and drum holder  13  in such a manner that the development unit u is rotationally moved relative to the cleaning unit v. As for the positional relationship between the development unit u and cleaning unit v in terms of the lengthwise direction of the cartridge  101 , one of the lengthwise ends of the cleaning device  11  is provided with a regulating portion (unshown), and the drum holder  13  is provided with an arm catching portion (unshown), as a regulating portion. Thus, the movement of the arm  81   a  in the lengthwise direction of the cartridge  101  is regulated by the arm movement regulating portion of the drum cleaning device  11  and the arm catching portion of the drum holder  13 , whereby the movement of the development unit u relative to the cleaning unit v in terms of the lengthwise direction of the cartridge  101  is regulated. 
         [0045]      FIG. 4  is a perspective view of the cartridge  101 . It shows the structure of the cartridge  101 . As is evident from  FIG. 4 , the left end of the cartridge  101  has a compression spring  86 , as a pressure applying member, which is fitted around the spring holder  84  ( FIGS. 3(   a ) and  3 ( b )) of the end member  82 . The right end of the cartridge  101  is provided with a compression spring  85 , as a pressure applying member, which is fitted around the spring holder  83  ( FIGS. 3(   a ) and  3 ( b )) of the end member  81 . The compression springs  86  and  85  are kept compressed between the end members  82  and  81 , and cleaning device  11 , whereby the development unit u is kept pressed toward the photosensitive drum  7 . Thus, the pair of gap maintaining members  10  ( FIG. 2) , with which the lengthwise ends of the development roller  10   d  are fitted one for one are kept in contact with the photosensitive drum  7 . Therefore, the development roller  10   d  and photosensitive drum  7  face each other with the presence of a preset gap between the two. With the employment of the above described structural arrangement, the cleaning unit v and development unit u can be connected to each other, without using connector pins or the like, in such a manner that the two units u and v are rotationally movable relative to each other. Further, the drum holder  13 , which is at the right end of the cartridge  101 , supports both the photosensitive drum  7  and development unit u (more specifically, right shaft  81   b ). Therefore, the development roller  10   d  supported by the development unit u are precisely positioned relatively to the photosensitive drum  7 . 
         [0046]    Next, referring to  FIG. 3(   a ), as described previously, the right end of the cartridge  101  has the drum gear  7   a  through which the force for driving the photosensitive drum  7  is transmitted to the photosensitive drum  7  from the apparatus main assembly  100 A. It is also provided with the development roller gear (unshown) through which the force from the apparatus main assembly  100 A is transmitted to the development roller  10   d;  the development roller gear is attached to the right end of the development roller  10   d.  Further, the right end of the cartridge  101  is provided with an idler gear (unshown) through which the driving force from the development roller gear is transmitted to the gear (unshown) connected to the developer conveyance member  39  ( FIG. 2) . The development roller gear, developer conveyance member gear, and idler gear, which make up a gear train, are covered with the right end member  81 . 
       Embodiment 1 
       [0047]      FIG. 5(   a ) is an exploded perspective view of the right end portion of the photosensitive drum  7 , that is, the end portion having the electrical connector  21 , in-the first preferred embodiment of the present invention. It shows the structure of the right end portion of the photosensitive drum  7 . As is evident from  FIG. 5(   a ), the photosensitive drum  7  comprises the cylindrical member  7   e,  an electrical connector  21 , and a flange  41 . The cylindrical member  7   e  is electrically conductive. Its peripheral-surface is covered with a photoconductive layer. The flange  41  is for immovably supporting the electrical connector  21  within the cylindrical member  21 . 
         [0048]    The electrical connector  21  is for keeping electrical connection between the cylindrical member  7   e  and the apparatus main assembly  100 A. It has a pair of first portions of contact  21   a  and a pair of second portions of contact  21   b.  The first portion of contact  21   a  is the portion of the electrical connector  21 , by which the connector  21  contacts the inward surface of the cylindrical member  7   e.  The second portion of contact  21  is the portion of the electrical connector  21 , by which the connector  21  contacts the drum shaft  61 , as an “external electrical connector”, which is has electrical connection to the outside of the cylindrical member  7   e.  The electrical connector  21  is made of metallic plate. It is structured as described above so that it maintains electrical connection with the outside. Hereafter, a hypothetical line which coincides with the axial line of the cylindrical member  7   e  is referred to as an axial line L, and a hypothetical vertical plane which includes the axial line L is referred to as a hypothetical plane M. Next, the structure of the electrical connector  21  is described in more detail with reference to the axial line L and hypothetical plane M. The axial line L and hypothetical plane M are shown only in  FIG. 5(   a ); they are not shown in  FIGS. 5-15 . However, all the electrical connectors shown in  FIGS. 5-15  also are described with reference to the axial line L and hypothetical plane M. 
         [0049]    The electrical connector  21  has a base section  21   k,  a first section  21 X, and a second section  21 Y. The first section  21 X extends from the base section  21   k  and is flexible (first flexible section). The second section  21 Y extends from the first section  21 X, and is flexible (second flexible section). That is, each of the first and second sections  21 X and  21 Y is a part of the electric current path between the first and second portions of contact  21   a  and  21   b,  and is flexible. 
         [0050]    The first section  21 X has a first horizontal portion  21   f  and a first vertical portion  21   c.  The first horizontal portion  21   f  extends from the base section  21   k,  and the first vertical portion  21   c  extends from the first horizontal portion  21   f.  The first horizontal portion  21   f  is parallel to the axial line L, that is, the direction parallel to the lengthwise direction of the cylindrical member  7   e.  It extends across the axial line L. The first vertical portion  21   c  is perpendicular to the axial line L, and parallel to the first diameter direction X of the hypothetical plane M. To describe the first diameter direction X in more detail with reference to  FIG. 5 , not only does it mean the straight downward direction of the electrical connector  21  when the electrical connector  21  is in its properly position in the cylindrical member  7   e,  but also, such a downward direction as the direction of the curvature of the electrical connector  21 , shown in  FIG. 9 , when the electrical connector  21  is in the proper position in the cylindrical member  7   e.  Further, it is not mandatory that the first diameter direction X is on the hypothetical plane M; the first diameter direction X may be on another plane which is parallel to the hypothetical plane M. 
         [0051]    The second section  21 Y has a second horizontal portion  21   g  and a second vertical portion  21   d.  The portion  21   g  extends toward the flange  41  from the first vertical portion  21   c  of the first section  21 X. It is parallel to the axial line L. The second vertical portion  21   d  extends from the second horizontal portion  21   g  of the second section  21 Y in the second diameter direction Y of the hypothetical plane M, which is opposite from the first diameter direction X, beyond the axial line L. To describe the second diameter direction Y in more detail with reference to  FIG. 5 , not only does it mean the straight upward direction of the electrical connector  21  when the electrical connector  21  is in its proper position in the cylindrical member  7   e,  but also, such an upward direction as the direction of the curvature of the electrical connector  21 , which is unshown, when the electrical connector  21  is in its proper position in cylindrical member  7   e.  Further, it is not mandatory that the second diameter direction Y is on the hypothetical plane M; the second diameter direction Y may be on another plane which is parallel to the hypothetical plane M. 
         [0052]    The first and second portions of contact  21   a  and  21   b,  and the first and second sections  21 X and  21 Y between the two portions of contact  21   a  and  21   b,  are integral parts of the electrical connector  21 . The first and second portions of contact  21   a  and  21   b  are electrically in connection to each other by way of the first and second sections  21 X and  21 Y. Further, the first and second sections  21 X and  21 Y are physically in connection to each other, and the second portion of contact  21   b  is physically in contact with the second section  21 Y (structurally connected). Further, the electrical connector  21  is structured so that as the drum shaft  61  comes into contact with the second portion of contact  21   b,  the second portion of contact  21   b  displaces in the direction parallel to the axial line L. 
         [0053]    The electrical connector  21  is structured so that when it is in its proper position in the cylindrical member  7   e,  the second portion of contact  21   b  intersects with the hypothetical plane M. However, it is not mandatory that when the electrical connector  21  is in its proper position in the cylindrical, member  7   e,  the second portion of contact  21   b  intersects with the hypothetical plane M; the second portion of contact  21   b  may be offset from the hypothetical plane M. Further, the electrical connector  21  is structured so that when it is in its proper position in the cylindrical member  7   e,  the second portion of contact  21   b  is on the axial line L, which coincides with the axial line of the cylindrical member  7   e.  However, it is not mandatory that when the electrical connector  21  is in its proper position in the cylindrical member  7   e,  the second portion of contact  21   b  is on the axial line L. 
         [0054]    The electrical connector  21  has the base section  21   k.  The base section  21   k  has multiple (two in this embodiment) holes for immovably attaching the electrical connector  21  to the flange  41 . It has also a hole  21   h,  through which the drum shaft  61  ( FIG. 6(   c )) or  64  ( FIG. 6(   d )) is put. The hole  21   h  is greater in diameter than the drum shaft  61 , and the hole  41   c  of the flange  41 . The hole  41   c  will be described later. 
         [0055]    The flange  41  has an electrical connector seat  41   a,  which accommodates the base section  21   k  of the electrical connector  21 . The electrical connector seat  41   a  has multiple (two in this embodiment) pins  41   b  for properly positioning the electrical connector  21  relative to the flange  41 . It has also a through hole  41   c,  which extends from the outward side of the flange  41   c  to the inward side, and through which the drum shaft  61  or external electrical connector  14  is put. The through hole  41   c  is slightly greater in diameter than the drum shaft  61  or external electrical connector  14 . The direction of the through hole  41   c  is such that after the electrical connector  21  is properly attached to the flange  41 , the axial line of the flange  41  coincides with the axial line L. 
         [0056]      FIG. 5(   b ) is a perspective view of the photosensitive drum  7 . It shows the structure of the photosensitive drum  7 . The procedure for attaching the lo electrical connector  21  to the photosensitive drum  7  is as follows: First, the electrical connector  21  is attached to the flange  41 . Then, the combination of the electrical connector  21  and flange  41  is attached to the cylindrical member  7   e,  yielding thereby the photosensitive drum  7  shown in  FIG. 5(   b ). 
         [0057]      FIG. 6(   a ) is a perspective view of the combination of the electrical connector  21 , drum shaft  61 , and flange  41 . It shows the structural arrangement of the combination.  FIG. 6(   b ) is a plan view of the combination of the electrical connector  21 , drum shaft  61 , and flange  41 . It shows the structural arrangement of the combination. The two positioning pins  41   b  ( FIG. 5(   a )) of the flange  41  are put through the two positioning holes  21   i  ( FIG. 5(   a )) of the electrical connector  21 , whereby the electrical connector  21  and flange  41  are accurately positioned relative to each other. Then, the electrical connector  21  is fastened to the flange  41  by deforming (flattening) the tip of each positioning pin  41   b,  which protrudes from the base section  21   k,  by applying pressure to the tip while thermally softening the tip, as shown in  FIGS. 6(   a ) and  6 ( b ), which show the thermally flattened portions  41   h  of the multiple (two in this embodiment) positioning pins  41   b.    
         [0058]    Then, the combination of the electrical connector  21  and flange  41  is fastened to the cylindrical member  7   e,  whereby the electrical connector  21  is placed in the cylindrical member  7   e,  being thereby accurately positioned relative to the photosensitive drum  7 . The presence of the flange  41  makes it possible for an assembly worker to attach the electrical connector  21  to the cylindrical member  7   e  without touching the electrical connector  21 . Thus, it can prevent the electrical connector  21  from being accidentally deformed when it is attached to the cylindrical member  7   e.    
         [0059]      FIG. 6(   c ) is a sectional view of the right end portion of the photosensitive drum  7 . It shows the structure of the right end portion. It corresponds to the area of  FIG. 6(   a ) surrounded by a broken line. As is evident from  FIG. 6(   c ), the first portion of contact  21   a  is in contact with the inward surface of the cylindridal member  7   e.  Inside the cartridge  101 , or apparatus main assembly  100 A, the inward portion of contact  61   a  of the drum shaft  61 , which is semispherical, is in contact with the second portion of contact  21   b  of the electrical connector  21 . Thus, as the positional relationship between the cylindrical member  7   e  and drum shaft  61  changes in such a manner that the inward portion of contact  61   a  of the drum shaft  61  is moved inward of the photosensitive drum  7  from the initial portion of contact between the inward portion of contact  61   a  and second portion of contact  21   b,  the second portion of contact  12   b  is displaced in the direction parallel to the axial line L, in the cylindrical member  7   e.  As the second portion of contact  12   b  is displaced, the first vertical portion  21   c,  the first and second horizontal portions  21   c  and  21   d,  which are springy, are resiliently bent, whereby the second portion of contact  12   b  is kept in contact with the inward portion of contact  61   a  of the drum shaft  61  with the presence of a preset amount of contact pressure between the two. Thus, it is ensured that the cylindrical member  7   e  maintains electrical connection with the apparatus main assembly  100 A. 
         [0060]    The drum shaft  61  in this embodiment is made of a metallic substance. However, this embodiment is not intended to limit the present invention in scope. That is, the drum shaft  61  may be replaced with any shaft which is the same in size as the shaft  61  and is made of an electrically conductive substance. For example, the drum shaft  61  may be made of metallic plate. Further, the drum shaft  61  may be replaced with a drum shaft  64  ( FIG. 6(   d )), the inward tip  64   a,  as the internal point of contact of the external electrical connector, which is pointed. 
         [0061]    In a case where a large number of the electrical connectors  21  are formed of a springy substance, each electrical connector  21  is different from the other electrical connector  21  in the manner in which it resiliently bends, because of the manufacture errors. Therefore, it is not with a specific point of the second portion of contact  21   b  of the electrical. connector  21  that the inward end of the drum shaft  61  remains in contact. That is, the point of contact between the second portion of contact  21   b  and the inward end of the drum shaft  61  shifts within a certain range, which is not very wide. Thus, in order to ensure that as long as the inward end of the drum shaft  61  remains in contact with this limited area of the second portion of contact  21   b  of the electrical connector  21 , the electrical connector  21  remains electrically connected to the drum shaft  61 , the manufacturing operation has to controlled in terms of the state (texture, adherents, etc.) of the surface of the electrical connector  21 , in particular, the second portion  21   b  of contact of the electrical connector  21 . 
         [0062]      FIG. 6(   d ) is a sectional view of the drum shaft  64 , as an external electrical connector, with which the drum shaft  61  can be replaced. It shows the structure of the shaft  64 . As is evident from  FIG. 6(   d ), with the use of the drum shaft  64 , the inward end of which is pointed, the area of the inward end portion of the drum shaft  64 , with which the second portion of contact  21   b  of the second section  21 Y of the electrical connector  21  comes into contact, is limited to a single point, that is, the inward end  64   a.  Thus, using the drum shaft  64  in place of the drum shaft  61  affords more latitude in the manufacturing of the cartridge  101 . 
         [0063]    Incidentally, as described previously, the hole  21   h  ( FIG. 5(   a )) of the electrical connector  21  is made greater in diameter than the hole  41   c  of the flange  41 . Therefore, even if the drum shaft  61  becomes angled relative to the axial line L of the cylindrical member  7   e,  the drum shaft  61  is prevented from coming into contact with the base section  21   k  of the electrical connector  21 . 
         [0064]    As described above, according to this embodiment, in order to allow the residual charge of the photosensitive drum  7  to escape to the apparatus main assembly  100 A, the electrical connector  21  is formed of an electrically conductive springy substance. Further, as the drum shaft  61  is inserted into the hole of the flange  41 , not only does the second portion of contact  21   b  of the electrical connector  21  come into contact with the drum shaft  61 , but also, it is displaced in the direction parallel to the axial line L of the cylindrical member  7   e.  Thus, it is ensured by the springiness of the electrical connector  21  that the second portion of contact  21   b  is kept in contact with the drum shaft  61  with the presence of a certain amount of contact pressure between the second portion of contact  21   b  and drum shaft  61 . 
       Embodiment 2  
       [0065]      FIG. 7(   a ) is an exploded perspective view of the right end portion of the photosensitive drum  207  in the second preferred embodiment of the present invention. It shows the structure of the right end portion of the photosensitive drum  207 , which has an electrical connector  22 .  FIG. 7(   b ) is a perspective view of the right end portion of the photosensitive drum  207 . It shows the structure of the right end portion. The structural components of the photosensitive drum  207  in the second embodiment, which are the same in structure and effects as the counterparts in the first embodiment, are given the same referential codes as those given to the counterparts one for, one, and are not going to be described here. The cartridge and image forming apparatus to which the electrical connector  22  in the second embodiment is compatible are the same as the one in the first embodiment. Therefore, they are not going to be described here. The difference between the right end of the photosensitive drum in this embodiment and that in the first embodiment is as follows: The right end of the photosensitive drum in this embodiment has no flange  41 . Instead, the electrical connector  22  in this embodiment is provided with a pair of anchoring portions  22   g,  with which the electrical connector  22  is fastened to the right end of the cylindrical member  7   e.    
         [0066]    Referring to  FIG. 7(   a ), the electrical connector  22  has a pair of anchoring portions  22   g,  which are in the form of a clip and extend from the base section  21   k.  More specifically, the pair of anchoring portions  22   g  extend from the left and right ends of the base section  21   k,  one for one, in terms of the direction perpendicular to the first and second sections  21 X and  21 Y of the electrical connector  22 . Each anchoring portion  22   g  extends a preset length from the base section  21   k  in the opposite direction from the second portion of contact  21   b,  and doubles back toward the second portion of contact  21   b,  providing thereby the anchoring portion  22   g  with a recess  22   g   1 , in which the end portion of the cylindrical member  7   e  is fitted. In other words, the electrical connector  22  is placed and retained in the cylindrical member  7   e  by being directly fastened to the cylindrical member  7   e  by its anchoring portions  22   g.  That is, in this embodiment, the electrical connector  22  is held to the photosensitive drum  207  without the flange  41 . 
         [0067]      FIG. 8(   a ) is a perspective view of the combination of the electrical connector  22  and drum shaft  61 . It shows the structure of the combination.  FIG. 8(   b ) is a plan view of the combination of the cylindrical member  7   e  (right end portion) and electrical connector  22 . It shows the structure of the combination.  FIG. 8(   c ) is a sectional view of the cylindrical member  7   e  (right end portion), electrical. connector  22 , and drum shaft  61 , at the aforementioned plane M. It shows the structure of the combination. As is evident from the drawings, a part of the anchoring portion  22   g  fits on the outward side of the cylindrical member  7   e.  Otherwise, the electrical connector  22  is the same in structure as the electrical connector  21  in the first embodiment. Therefore, the effects of the electrical connector  22  are the same as those of the electrical connector  21 . 
       Embodiment 3 
       [0068]      FIG. 9(   a ) is a perspective view of the combination of the electrical connector  23 , drum shaft  61 , and flange  41  in the third preferred embodiment. It shows the structure of the combination.  FIG. 9(   b ) is a plan view of the combination of the cylindrical member  7   e  (right end portion), electrical connector  23 , and flange  41 . It shows the structure of the combination.  FIG. 9(   c ) is a sectional view of the cylindrical member  7   e  (right end portion), electrical connector  23 , flange  41 , and drum shaft  61 , at the aforementioned plane M. It shows the structure of the combination. The structural components of the photosensitive drum  307  in the third embodiment, which are the same in structure and effects as the counterparts in the first and second embodiments are given the same referential codes as those given to the counterparts one for one, and are not going to be described here. The cartridge and image forming apparatus to which the electrical connector  22  in the third embodiment is compatible are the same as those in the first embodiment. Therefore, they are not going to be described here. The electrical connector  23  in the third embodiment is different from the electrical connectors  21  and  22  in the first and second embodiments in that the electrical connector  23  does not have portions equivalent to the portions  21   c,  and  21   g.  Instead, it has a portion  23   c  which semicircularly extends from the portion  21   f,  and the second portion  21   d  extends from the portion  23   c.    
         [0069]    As is evident from  FIGS. 9(   a )- 9 ( c ), the electrical connector  23  has the portion  21   f,  which is a part of the “first flexible section” which extends from the base section  21   k.  That is, it is from the portion  21   f  that the semicircular portion  23   c,  which is a part of the first flexible portion  23   c,  extends. From the portion  21   f,  the second vertical portion  21   d,  which is a part of the “second flexible section”, extends. As seen from the direction perpendicular to the hypothetical plane M of the cylindrical member  7   e,  the portion  23   c  appears semicircular, and extends beyond the axial line L. 
       Embodiment 4 
       [0070]      FIG. 10(   a ) is a perspective view of the combination of the electrical connector  24  and drum shaft  61  in the fourth preferred embodiment of the present invention. It shows the structure of the combination.  FIG. 10(   b ) is a plan view of the combination of the photosensitive drum  407  (right end portion) and electrical connector  24 . It shows the structure of the combination.  FIG. 10(   c ) is a sectional view of the electrical connector  24 , cylindrical member  407   e  (right end portion), and drum shaft  61 , at the aforementioned plane M. It shows the structure of the combination. The structural components of the photosensitive drum  407 , cartridge, and image forming apparatus in the fourth embodiment, which are the same in structure and effects as the counterparts in the first to third embodiments are given the same referential codes, and are not going to be described here. The cartridge and image forming apparatus to which the electrical connector  24  in this embodiment is compatible are the same as those in the first embodiment. Therefore, they are not going to be described here. The electrical connector  24  in the fourth embodiment is different from the electrical connector  21 - 23  in the first to third embodiments in that the electrical connector  24  has portions  24   f,    24   c,    24   h,    24   d,  and  24   k,  and the portions  24   f  and  24   h  extend in the opposite direction from the direction in which their counterparts in the preceding embodiments extend. 
         [0071]    Referring to  FIGS. 10(   a )- 10 ( c ), the electrical connector  24  has the base section  21   k,  first horizontal portions  24   f,  first vertical portion  24   c,  second horizontal portion  24   h,  and second vertical portion  24   d.  The first horizontal portion  24   f  is a part of the “first flexible section” and extends from the base section  21   k  toward the drum shaft  61  in the direction parallel to the axial line L. The first vertical portion  24   c  is a part of the “first flexible section”. It extends from the end of the portion  24   f  in the first diameter direction X, which is perpendicular to the axial line L. From the end of the portion  24   c,  the second horizontal portion  24   h,  which is a part of the “second flexible section”, extends toward the drum shaft  61  in the direction parallel to the axial line L. From the end of the portion  24   h,  the second vertical portion  24   d,  which is a part of the “second flexible section”, extends in the second diameter direction Y, which is perpendicular to the axial line L. The portions  24   f,    24   c,    24   h,  and  24   d  are parallel to the hypothetical plane M. Further, the vertical portions  24   c  and  24   d  extend across the axial line L. 
         [0072]      FIG. 10(   d ) is a perspective view of the electrical connector  24 . As is evident from.  FIG. 10(   d ), the electrical connector  24  has the base section  24   k.  The base section  24   k  has a pair of first portions of contact  21   a,  which extend from the top and bottom ends of the base section  24   k.  The aforementioned first horizontal portion  24   f  extends in the direction perpendicular to the axial line L from the point of the base section  21   k,  from which the top first portion of contact  21   a  extends. It is from the portion  24   f  that the portion  24   c  extends from the direction perpendicular to the axial, line L. From the portion  24   c,  the portion  24   h  extends in the direction parallel to the axial line L. It is from the portion  24   h  that the portion  24   d  extends in the direction perpendicular to the axial line L. The portion  24   d  has the second portion of contact  24   b  as does the counterparts in the first and second embodiments. Further, the electrical connector  24  has a pair of anchoring portions  24   g  for fastening the electrical connector  24  to the end of the cylindrical member  407   e.  The anchoring portion  24   g  has a recess (gap)  24   g   1  in which the end of the cylindrical member  407   e  is fitted. 
       Embodiment 5 
       [0073]      FIG. 11(   a ) is a perspective view of the combination of the electrical connector  25 ; drum shaft  62 , and flange  41  in the fifth preferred embodiment of the present invention. It shows the structure of the combination.  FIG. 11(   b ) is a plan view of the combination of the cylindrical member  507   e  (right end portion), electrical connector  25 , and flange  41 . It shows the structure of the combination.  FIG. 11(   c ) is a sectional view of the cylindrical member  507   e  (right end portion), electrical connector  25 , flange  41 , and drum shaft  62 , at the aforementioned plane M. It shows the structure of the combination. The structural components of the photosensitive drum  507 , cartridge, and image forming apparatus in the fifth embodiment, which are the same in structure and effects as the counterparts in the first to fourth embodiments are given the same referential codes as those given to the counterparts, and are not going to be described here. The cartridge and image forming apparatus to which the electrical connector  25  in this embodiment is compatible are the same as those in the first embodiment. Therefore, they are not going to be described here. The electrical connector  25  in the fifth embodiment is different from the electrical connector  21 - 24  in the first to fourth embodiments in that the electrical connector  25  has a portion  25   e  (protrusion) which protrude from the end of the portion of contact  25   b  toward the shaft  62  in the direction parallel to the axial line L. 
         [0074]    The electrical connector  25  is a component that contacts the cylindrical member  7   e  which is electrically conductive and the peripheral surface of which is covered with the photosensitive layer. It has a pair of first portions of contact  21   a  by which it contacts the inward surface of the cylindrical member  7   e.    
         [0075]    Further, the electrical connector  25  is a component that contacts the drum shaft  62  which functions as the “external electrical connector”. It has a pair of second portions of contact  25   b  by which it contacts the drum shaft  62  which extends outward of the cylindrical member  7   e.  The electrical connector  25  is made of electrically conductive metallic plate, and is structured as described above to maintain electrical connection between the inward surface of the cylindrical member  7   e  and the outside of the photosensitive drum  507 . 
         [0076]    Referring to  FIGS. 11(   a )- 11 ( c ), the electrical connector  25  has the first portions of contact  21   f,  first vertical portion  21   c,  second horizontal portion  21   g,  and second vertical portion  21   d.  The second vertical portion  21   d  has the second portion of contact  25   b.  The second portion of contact  25   b  has the protrusion  25   e  which extends toward the drum shaft  62 . In this embodiment, the drum shaft  62  is employed as the “external electrical connector”. The inward end of the drum shaft  62  is flat. (flat surface  62   a ). The electrical connector  25  and flange  41  are structured so that the protrusion  25   e  of the second portion of contact  25   b  of the electrical connector  25  contacts this flat surface  62   a  of the drum shaft  62 . 
         [0077]    In the first to fourth embodiment, the inward end portion  61   a  of the drum shaft  61 , by which the drum shaft  61  contacts the electrical connector  21 ,  22 ,  23 , or  24 , was pointed or spherical, whereas the portion of the electrical connector  21 ,  22 ,  34 , or  24 , by which the electrical connector  21 ,  22 ,  23 , or  24  contacts the drum shaft  61 , was flat (second vertical portion  21   b ). In this embodiment, the portion of the electrical connector  25 , by which the electrical connector  25  contacts the drum shaft  62 , is the horizontal protrusion  25   e  of the electrical connector  25 , whereas the portion of the drum shaft  62 , by which the drum shaft  62  contacts the electrical connector  25  is the flat surface  62   a  of the inward end of the drum shaft  62 . That is, the fifth embodiment is opposite from the first to fourth embodiments in terms of the relationship between the shape of the portion of contact of the electrical connector and the shape of the portion of contact of the drum shaft. 
         [0078]      FIG. 12(   a ) is a perspective view of the combination of the electrical connector  26 , drum shaft  62 , and flange  41  in one of the modified versions of the fifth embodiment. It shows the structure of the combination.  FIG. 12(   b ) is a plan view of the combination of the cylindrical member  1507   e,  electrical connector  26 , and flange  41 . It also shows the structure of the combination.  FIG. 12(   c ) is a sectional view of the right end portion of the photosensitive drum  1507 , at the hypothetical plane M.  FIG. 12(   d ) is an enlarged perspective view of the protrusion  26   e  of the electrical connector  26 . The electrical connector  26  is a component which contacts the cylindrical member  1507   e  (which is electrically conductive, and peripheral surface of which is covered with photosensitive layer). It has a pair of first portion of contacts  21   a,  which contact the inward surface of the cylindrical member  1507   e.  Further, the electrical connector  26  contacts the drum shaft,  62 , as the “external electrical connector”, which&#39;has electrical connection to the outside of the cylindrical member  7   e.  It has the second portion of contact  26   b  which contacts the drum shaft  62 , which extends outward of the cylindrical member  7 . The electrical connector  26  is made of electrically conductive metallic plate, and is structured as described above so that it maintains electrical connection with the outside of the photosensitive drum  1507 . 
         [0079]    Referring to  FIGS. 12(   a )- 12 ( d ), the electrical connector  26  has the first horizontal portion  21   f,  first vertical portion  21   c,  and second horizontal portion  21   g.  Further, the electrical connector  26  has the second vertical portion  26   d,  which extends from the end of the second horizontal portion  21   g  in the direction perpendicular to the axial line L. The second vertical portion  26   d  has the second portion of contact  26   b,  which is provided with the protrusion  26   e  formed by embossing the second portion of contact  26   b.    
       Embodiment 6 
       [0080]      FIG. 13(   a ) is a perspective view of the combination of the electrical connector  27 , drum shaft  62 , and flange  41  in the sixth preferred embodiment of the present invention. It shows the structure of the combination.  FIG. 13(   b ) is a plan view of the combination of the cylindrical member  7   e,  electrical connector  27 , and flange  41 . It shows the structure of the combination.  FIG. 13(   c ) is a sectional view of the right end portion of the photosensitive drum  607 . It shows the structure of the right end portion.  FIG. 13(   d ) is a perspective view of the electrical connector  27 , and shows the structure of the electrical connector  27 . The structural components of the photosensitive drum  607 , cartridge, and image forming apparatus in the sixth embodiment, which are the same in structure and effects as the counterparts in the first to fifth embodiments, are given the same referential codes as those given to the counterparts, one for one, and are not going to be described here. The cartridge and image forming apparatus in the sixth embodiment are the same as those in the first embodiment, and therefore, are not going to be described here. The electrical connector  27  in the sixth embodiment is different from the electrical connector  21 - 26  in the first to fifth embodiments in that the first and second vertical portions  27   c  and  27   d  are narrower than the first and second horizontal portions  21   f  and  21   g.    
         [0081]    The electrical connector  27  contacts the cylindrical member  607   e  (which is electrically conductive, and peripheral surface of which has photosensitive layer), and has a pair of first portions of contact  21   a,  by which it contacts the inward surface of the cylindrical member  607   e.  Further, the electrical connector  27  contacts the drum shaft  62 , as the “external electrical connector” which extends outward of the cylindrical member  7   e.  It has a second portion of contact  27   b,  with which it contacts the drum shaft  26  which extends outward of the cylindrical member  607   e.  It is made of electrically conductive metallic plate, and is structured so that it maintains electrical connector with the outside. 
         [0082]    Referring to  FIG. 13 , in the following description of the sixth embodiment, the portions of the electrical connector  27 , which are parallel to the axial line L will be referred to as the horizontal portions, whereas the portions of the electrical connector  27 , which are perpendicular to the axial line L will be referred to as the vertical portions. The first section  21 X of the electrical connector  27  comprises the horizontal portion  21   f  and first vertical portion  27   c.  The second section  21 Y of the electrical connector  27  comprises the second horizontal portion  27   g  and second vertical portion  27   d.  Further, the first and second vertical portions  27   c  and  27   d  are narrower than the first and second horizontal portions  21   f  and  21   g.    
         [0083]    Referring to  FIG. 13(   d ), the electrical connector  27  has the first and second horizontal portions  27   c  and  27   d,  which are perpendicular to the axial line L which coincides with the axial line of the cylindrical member  7   e,  and the horizontal portions  27   f  and  27   g  which are parallel to the axial line L. The first and second vertical portions  27   c  and  27   d  are partially narrower than the first and second horizontal portions  27   f  and  27   g.  The electrical connector  27  is made of springy plate, and is structured so that there is the following relationship among the widths X 1  and X 2  of the first and second vertical portions  27   c  and  27   d,  respectively, and the widths X 3  and X 4  of the first and second horizontal portions  27   f  and  27   g,  respectively: X 1 , X 2 &lt;X 3 , X 4 . Next, referring to  FIG. 13(   c ), the first and second vertical portions  27   c  and  27   d  are more likely to resiliently bend (function as springs) in the direction (parallel to axial line L or axial line of cylindrical member  607   e ) in which the second portion of contact  27   b  displaces than the first and second horizontal portions  27   f  and  27   g.  Thus, the electrical connector  27  is structured so that it is easier for the first and second vertical portions  27   c  and  27   d  to resiliently bend (function as springs) than the first and second horizontal portions  27   f  and  27   g.  Thus, electrical connector  27  is more resistant to permanent deformation (plastic deformation), being therefore more stable in electrical connection than the electrical connectors  21 - 26  in the first to fifth embodiments. 
         [0084]    Next, referring to  FIG. 13(   b ), the electrical connector  27  is fastened to the flange  41  by the flattening of a pair of connector positioning pins. More specifically, the flange  41  is provided with a pair  41   b  of pins ( FIG. 5)  which are for positioning the electrical connector  27  relative to the flange  41  and can be thermally flattened. After the electrical connector  27  is properly positioned relative to the flange  41  with the help from the pints  41   b,  the pins  41   b  are flattened into the portions  41   h  (thermally flattened portions) by, the pressure applied thereto while the pints  41   b  are kept soft by the application of heat. Incidentally, in a case where a flattening horn is used to flatten the heads of the pins  41   b,  the first and second vertical portions  27   c  and  27   d  may be made narrower than the first and second horizontal portions  27   f  and  27   g  (X 1 , X 2 &lt;X 3 , X 4 ) in order to make it easier to insert the flattening horn. 
       Embodiment 7 
       [0085]      FIG. 14(   a ) is a perspective view of the combination of the electrical connector  28 , drum shaft  63 , and flange  42  in the seventh preferred embodiment of the present invention. It shows the structure of the combination.  FIG. 14(   b ) is a plan view of the combination of the cylindrical member  707   e,  electrical connector  28 , and flange  42 . It shows the structure of the combination.  FIG. 14(   c ) is a sectional view of the right end portion of the photosensitive drum  707 . It shows the structure of the right end portion. The structural components of the photosensitive drum  707 , cartridge, and image forming apparatus in the seventh embodiment, which are the same in structure and effects as the counterparts in the first to sixth embodiments, are given the same referential codes as those given to the counterparts, one for one, and are not going to be described here. The cartridge and image forming apparatus in the seventh embodiment are the same as those in the first embodiment, and therefore, are not going to be described here. The electrical connector  28  and its adjacencies in the seventh embodiment are different from the electrical connector  21 - 26  and their adjacencies in the first to sixth embodiments is that in this embodiment, the drum shaft  63  is supported by the flange  42  by being fitted in the flange  42 . The structure of the electrical connector  28  is the same as that of the electrical connector  27 . 
         [0086]    Referring to  FIG. 14 , the electrical connector  28  is a component which contacts the cylindrical member  707   e  (which is electrically conductive, and peripheral surface of which is covered with photosensitive layer). It has a pair of first portions of contact  21   a  which contact the inward surface of the cylindrical member  7   e.  It contacts also the drum shaft  63 , as the “external electrical connector”, which has electrical connection with the outside of the cylindrical member  7   e.  It has also a second portion of contact  27   b  which contacts the drum shaft  63  which extends outward of the cylindrical member  707   e.  The electrical connector  28  is made of electrically conductive metallic plate, and is structured as described above to maintain electrical connection with the outside. 
         [0087]    The flange  42  has a through hole  42   f,  through which the drum shaft  63  (external electrical connector) is put in such a manner that there is virtually not gap between the peripheral surface  63   h  of the drum shaft  63  and the inward surface of the hole  42   f.  In other words, the drum shaft  63  is supported by the flange  42 , whereby the both the second portion of contact  27   b  (protrusion  27   e ), and the drum shaft  63  (flat surface  63   a  at the inward end of shaft  63 ) are properly positioned relative to each other. Therefore, the combination of the electrical connector  28 , flange  43 , and shaft  63  is more stable in electrical connection than those in the first to sixth embodiments. 
         [0088]    The structural arrangement related to the abovementioned combination may be modified so that the drum shaft  63  is fastened to the flange  42  by crimping to make the drum shaft  63  an integral part of the structural component of the photosensitive drum  707 , and therefore, the drum shaft  63  rotates with the photosensitive drum  707 . 
         [0089]    Further, the structural arrangement related to the abovementioned combination may be modified so that the drum shaft  63  is solidly attached to the frame of the cartridge  101  or apparatus main assembly  100 A, and a minute gap is present between the peripheral surface of the drum shaft  63  and the internal surface of the hole  42   f  of the flange  42  to rotatably support the photosensitive drum  707  with the drum shaft  63 . In such a case, as the photosensitive drum  707  rotates, the protrusion  28   e  of the electrical connector  28  slides on the flat surface  63   a  of the drum shaft  63 , maintaining thereby electrical connection between the electrical connector  28  and drum shaft  63 . Further, in such a case, the point of contact between the protrusion  28   e  and drum shaft  63  virtually coincides with the rotational axis of the drum shaft  63  (photosensitive drum  707 ). Therefore, the electrical connector  28  is more stable in electrical connection. 
       Embodiment 8 
       [0090]    “ FIG. 15(   a ) is a perspective view of the combination of the electrical connector  29 , external electrical connector  14 , flange  42 , and cartridge frame  71  in the eighth preferred embodiment of the present invention. It shows the structure of the combination.  FIG. 15(   b ) is a plan view of the combination of the cylindrical member  7   e,  electrical connector  29 , and flange  42 . It shows the structure of the combination.  FIG. 15(   c ) is a sectional view of the right end portion of the photosensitive drum  807 . It shows the structure of the right end portion.  FIGS. 15(   d ) and  15 ( e ) are enlarged perspective views of the electrical connector  29 . They show the structure of the electrical connector  29 . The structural components of the photosensitive drum  807 , cartridge, and image forming apparatus in the eighth embodiment, which are the same in structure and effects as the counterparts in the first to seventh embodiments, are given the same referential codes as those given to the counterparts, one for one, and are not going to be described here. The cartridge and image forming apparatus in the eighth embodiment are the same as those in the first embodiment, and therefore, are not going to be described here. The difference between the electrical connector  29  and its adjacencies in the eighth embodiment, and the electrical connector  21 - 26  and their adjacencies in the first to seventh embodiments is as follows: 
         [0091]    To begin with, the electrical connector  29  has a base section  29   k  by which the electrical connector  29  is fastened to the flange  42 . The base section  29   k  has a through hole  29   h,  which is parallel to the axial line L of the cylindrical member  807   e.  The second portion of contact  29   b  of the electrical connector  29  is long enough to extend beyond the base section  29   k.  Further, the external electrical connector  14  is supported by the flanges  42  and cartridge frame  71 . 
         [0092]    The electrical connector  29  contacts the cylindrical member  807   e  (which is electrically conductive, and peripheral surface of which is covered with photosensitive layer). It has a pair of first portions of contact  29   a  which contact the inward surface of the cylindrical member  7   e.  It contacts also the external electrical connector  14 , as the “external electrical connector”, which has electrical connection with the outside of the cylindrical member  7   e.  It has also a second portion of contact  29   b  which contacts the external electrical connector  14  which extends outward of the cylindrical member  807   e.  The electrical connector  29  is made of electrically conductive metallic plate, and is structured as described above to maintain electrical connection with the outside. 
         [0093]    Referring to  FIG. 15(   d ), the electrical connector  29  has the base section  29   k  by which it is fastened to the flange  42 . It is structured so that its second portion of contact  29   b  extends toward the external electrical connector  14  beyond the base section  29   k  through the hole  29   h  of the base section  29   k.  Next, referring to  FIG. 15(   e ), the end of the second portion of contact  29   b  has a protrusion  29   e.  Next, referring to  FIG. 15(   a ), the outward end of the external electrical connector  14  is solidly attached to the frame  71  of the cartridge  101  by being pressed into a hole with which the frame  71  is provided for the external electrical connector  14 , or the like method, whereas the inward end portion of the external electrical connector  14  is fitted in the through hole of the flange  42  with the presence of virtually no gap between the peripheral surface of the external electrical connector  14  and the inward surface of the through hole of the flange  42  so that the photosensitive drum  807  is rotatably supported by the external electrical connector  14 . In a case where the dimension of the external electrical connector  14  in the direction parallel to the diameter direction of the cylindrical member  7   e  is greater than the dimension of the second portion of contact  29   b  in the same direction, the electrical connector  29  can be made greater in rigidity by putting the second portion of contact  29   b  through the hole  29   h  of the base section  29   k.  Further, the smaller the hole  29   h  of the base section  29   k,  the more rigid the electrical connector  29 . In other words, the electrical connector  29  in this embodiment is greater in rigidity, being therefore more resistant to the external load, and therefore, more stable in electrical connector, than the counterparts in the first to seventh embodiments. 
         [0094]    In this embodiment, the electrical connector  29  is attached to the cylindrical member  807   e  with the use of the flange  42 . However, the present invention is compatible with the electrical connector  29  even if the electrical connector  29  is modified to be directly fastened to the cylindrical member  807   e  ( FIGS. 7 and 8 ). The effects of the modified version of the electrical connector  29  are the same as the original version of the electrical connector  29 , which is to be attached to the cylindrical member  7   e  with the use of the flange  42 . 
         [0095]    Further, the above-described structural arrangement can be used to rotatably support the photosensitive drum  807  with the external electrical connector  14  by solidly supporting the external electrical connector  14  with the frame  71  of the cartridge  101  or the frame (unshown) of the apparatus main assembly  100 A, by the peripheral surface  14   h  of the external electrical connector  14  as shown in  FIGS. 15(   c ). In such a case, as the photosensitive drum  807  rotates, the protrusion  29   e  of the electrical connector  29  slides on the flat surface  14   a  of the inward end of the external electrical connector  14 , remaining thereby electrically in connection to the external electrical connector  14 . Further, the electrical connector  29  is structured so that the point of contact between the protrusion  29   e  of the electrical connector  29  and the external electrical connector  14  coincides with the rotational axis of the photosensitive drum  808 , that is, the rotational axis of the external electrical connector  14 . Therefore, the electrical connector  29  in this embodiment is more stable in electrical connector. 
         [0096]    According to the first to eighth preferred embodiments, the electrical connector  21 - 29  have the first and second flexible sections  21 X and  21 Y formed by putting a strip of electrically conductive springy metallic plate through such processes as bending by 90° or in curvature, doubling back, etc. The first flexible section  21 X has the first vertical portion, which extends in the first diameter direction X, whereas the second flexible section  21 Y has the second vertical portion which extends in the second diameter direction Y across the axial line L. Therefore, the electrical connector  21 - 29  to which the contact pressure between the external electrical connector  14  and second portion of contact of each of the electrical connector  21 - 29 , or the drum shaft  61 ,  62 , or  63  and the second portion of the contact can be made longer. Therefore, not only can the electrical connector  21 - 29  provide a contact pressure which is greater than a preset value, between the external electrical connector  14  and themselves, or between the drum shaft  61 ,  62 ,  63 , or  64  and themselves, but also, are substantially more resistant to the permanent deformation (plastic deformation). Therefore, they are more stable in terms of the electrical connection between themselves and the external electrical connector  14  or drum shaft  61 ,  62 ,  63 , or  64 , being therefore superior in terms of the release of the residual electrical charge of the photosensitive drum  7 ,  207 ,  307 ,  407 ,  507 ,  1507 ,  607 ,  707 , or  807 , to the apparatus main assembly  100 A, than any of the conventional counterparts. Therefore, they ensure that an image forming apparatus outputs excellent prints. 
         [0097]    Referring to  FIG. 6(   c ), in the first embodiment, the electrical connector  21  is structured so that the first and second vertical portions  21   c  and  21   d  extend in the first and second diameter directions X and Y, respectively, which is parallel to the hypothetical plane M which coincides with the axial line of the cylindrical member  7   e.  This structural arrangement is most effective to prevent the second portion of contact  21   b  from being displaced in the direction perpendicular to the axial line L. 
         [0098]    Next, referring to  FIG. 6(   b ), also in the first embodiment, the electrical connector  21  is structured so that the second vertical portion  21   d  of the electrical connector  21  is created by bending the second horizontal portion  21   g  in the opposite direction from the direction in which the first horizontal portion  21   f  is bent to form the first vertical portion  21   c.  This structural arrangement is very useful to create an electrical connector such as the electrical connector  21  which is substantial in length, and yet, can be placed in a small space. 
         [0099]    Further, in the first to eighth embodiments, the electrical connectors  21 - 28  are structured so that the centerline of the second portion of contact virtually coincides with the hypothetical plane M. In other words, the center line of the second portion of contact, centerline of the first vertical portions  21   c,  and centerline of the second vertical portion  21   d  virtually coincide with the hypothetical plane M. Thus, as the second portion of contact displaces in the direction parallel to the axial line L, the first and second horizontal portions  2   c  and  2   d  deform, accommodating thereby the movement (displacement) of the second portion of contact in the direction parallel to the axial line L. Therefore, the electrical connector  21 - 28  are minimized in terms of the distance by which the point of contact between the second portion of contact and the external electrical connector  14 , and the point of contact between the second portion of contact and the drum shafts  61 ,  62 ,  63 , or  64 , moves in the direction perpendicular to the axial line of the cylindrical member  7   e;  the displacement of the second portion of contact and drum shaft relative to each other is minimized. In other words, from the stand point of the design of the electrical connector, the second portion of contact and its area of contact does not need to be as large as the counterparts of the conventional electrical contact for a photosensitive drum, making it possible to reduce the electrical connector in cost. 
         [0100]    For example, in the first to eighth embodiments, the electrical connectors  21 - 28  are structured so that the second portion of contact intersects with the axial line L. Therefore; as the second portion of contact slides on the external electrical connector  14 , drum shaft  61 ,  62 ,  63 , or  64 , the point of contact remains on the rotational axis of the cylindrical member. Therefore, the electrical connector  21 - 28  are more stable in terms of the electrical connection between the second portion of contact and the external electrical connector  14 , drum shaft  61 ,  62 ,  63  or  64  than the conventional counterparts. 
         [0101]    According to the structural arrangement ( FIG. 7 ) for the electrical contact in the second embodiment, not only can the same effects as those provided by that in the first embodiment be provided, but also, the flange  41 , etc., can be eliminated. In other words, it can reduce an image forming apparatus, a process cartridge, etc., in component count, and therefore, can reduce them in cost. 
         [0102]    According to the structural arrangement (FIG.  9 ) for the electrical connector  23  in the third embodiment, the first “flexible” portion  23   c  is semicircular. However, the effects of this structural arrangement are the same as those obtainable by the structural arrangement for the electrical connector  21  in the first embodiment. Incidentally, the second “flexible” portion does not need to be semicircular. That is, it may be in any form, as long as it extends in the direction perpendicular to the axial line L across the axial line L. 
         [0103]    According to the structural arrangement ( FIG. 10 ) for the electrical connector  24  and its adjacencies in the fourth embodiment, the direction in which the electrical connector  24  extends is opposite to the direction in which the electrical connector  21  in the first embodiment does. However, the effect of this structural arrangement is the same as those obtainable by the electrical connector  21  in the first embodiment. That is, the direction in which the various portions of the electrical connector is to be bent in a manner of doubling back is optional, and so is the combination in which the various portions of the electrical connector are bent in a manner of doubling back. All that is necessary is that the electrical connector is shaped so that the first vertical portion  24   c  extends perpendicular to the axial line L across the axial line L within the cylindrical member  7   e,  and the second vertical portion  24   d  also extends perpendicular to the axial line across the axial line L in a manner of doubling back relative to the first vertical portion  24   c,  within the cylindrical member  7   e.    
         [0104]    Further, the electrical connector may be shaped so that a pair of portions of the electrical connector other than the combination of the first and second vertical portions  24   c  and  24   d  are parallel to each other and extend in a manner of doubling back relative to each other. For example, the electrical connector may be shaped so that the base section  21   k  and first vertical portion  24   c  are parallel to each other and extend in a manner of doubling back relative to each other. Further, it is desired that not only the electrical connector is shaped as described above in terms of the “doubling back”, but also, the pair of portions which extend in a manner of doubling back relative to each other are parallel to the first or second diameter direction X or Y and extend across the axial line L of the cylindrical member  7   e.  This structural arrangement is superior in terms of the minimization of the movement of the second portion of contact  24   b  in the diameter direction of the cylindrical member  7   e.    
         [0105]    According to the structural arrangement ( FIGS. 11 and 12 ) for the electrical connector  25  and  26  in the fifth embodiment, the second portions of contact  25   b  and  26  have the protrusions  25   e  and  26   e,  respectively, which are protrusive toward the drum shaft  62 . That is, the electrical connector  25  and  26  are provided with a specific point of contact, with which they contact the drum shaft  62 . Therefore, they are more stable in terms of electrical connection. Further, the second portions of contacts  25   b  and  26   b  themselves do not function as a spring. Therefore, even in consideration of the errors in the manufacturing of an electrical connector, the area of the electrical connector  25  and that of the electrical connector  26 , by which the electrical connector  25  and  26  contact the drum shaft  62  may be smaller than the counterparts in the first to fourth embodiments. In other words, this structural arrangement can afford more latitude in the control of the manufacturing process for an electrical connector. Therefore, it makes it easier to manufacture an electrical connector. 
         [0106]    According to the structural arrangement ( FIG. 13 ) for the electrical connector  27  in the sixth embodiment, the electrical connector  27  has the horizontal portions  21   f  and  21   g,  and the first and second vertical portions  27   c  and  27   d.  Further, the electrical connector  27  is structured so that the first and second vertical portions  27   c  and  27   d  are partially narrower than the horizontal portions  21   f  and  21   g.  Therefore, the first and second vertical portions  27   c  and  27   d,  which are to function as a spring, are more flexible in the direction in which the second portion of contact  27   b  displaces. Therefore the horizontal portions  21   f  and  21   g  which are not to function as a spring are unlikely to bend. Thus, the electrical connector  27  in the sixth embodiment is more resistant to the permanent deformation (plastic deformation) than the electrical connector in the first to sixth embodiments. 
         [0107]    Also referring to  FIG. 13 , this structural arrangement makes it possible to move a flattening horn toward the positioning pins  41   b  in a straight line indicated by an arrow mark P when thermally flattening the head portions of the positioning pins  41   b.  That is, this structural arrangement can provide a space through which a flattening horn can be easily inserted. That is, this structural arrangement makes it possible to more reliably fasten an electrical connector to the flange  41 . Thus, not only is the electrical connector  27  in this embodiment more stable in electrical connection, but also, easier to attach to the flange  41 . 
         [0108]    According to the structural arrangement ( FIG. 14 ) for the electrical connector  28  and its adjacencies in the seventh embodiment, the drum shaft  63  is supported by the flange  42 . Therefore, the positional relation between the second portion of contact  27   b  and drum shaft  63  is determined by the flange  42 , whereby the second portion of contact  27   b  and drum shaft  63  are positioned more precisely positioned relative to each other than the counterparts in the first to seventh embodiments. Therefore, the cartridge and image forming apparatus in this embodiment are more stable in electrical connection. 
         [0109]    According to the structural arrangement ( FIG. 15 ) for the electrical connector  29  and its adjacencies in the eighth embodiment, the electrical connector  29  has the base section  29   k,  and the second portion of contact  29   b  extends toward the drum shaft  63  through the hole of the base section  29   k.  Further, in a case where the diameter of the drum shaft  63  is greater than the dimension of the second portion of contact  29   b  in terms of the diameter direction of the cylindrical member  807   e,  not only can the hole, with which the base section  29   k  of the electrical connector  29  has to provided, be minimized in diameter by putting the second portion of contact  29   b,  which is narrower than the diameter of the drum shaft  63 , through the hole of the electrical connector  29 , but also, the electrical contact  29  can be made more rigid. That is, the structural arrangement for the electrical connector  29  in the eighth embodiment can make an electrical connector easier to handle during the manufacturing of the cartridge  101  and image forming apparatus  100 , and also, can make an electrical connector more stable in electrical connection. 
         [0110]    Further, the drum shaft  63  is supported by the flange  42 . Thus, the positional relationship between the second portion of contact  29   b  and drum shaft  63  is determined by the flange  42 . Therefore, the second portion of contact  29   b  and drum shaft  63  are more precisely positioned relative to each other. In other words, this structural arrangement can make the cartridge and image forming apparatus more stable in electrical connection than those in the first to seventh embodiments. 
         [0111]    The first and second portions of contact  21   a  and  21   b  of each of the electrical connector  21 - 29 , and the first and second sections  21 X and  21 Y of each of the electrical connectors  21 - 29 , in the first to eighth embodiments, respectively, are formed of a single piece of plate spring, being therefore smaller in component count, and therefore, smaller is the number of assembly steps, compared to electrical connectors made of two or more components. 
         [0112]    In the first, third, fifth, sixth, seventh, and eighth embodiments, and modified version of the fifth embodiment, the electrical connector  21 - 29  are fastened to the flange  41  or  42 , and the flanges  41  and  42  are fastened to one of the lengthwise ends of the cylindrical member  7   e.  This structural arrangement makes it possible for the electrical connector  21 - 29  to be attached to the cylindrical member  7   e  after being fastened to the flange  41  or  42 , which is rigid. Thus, this structural arrangement is superior in terms of assembly efficiency than the structural arrangement for the electrical connector  21 - 29  and their adjacencies, which requires the electrical connector  21 - 29  to be directly attached to the cylindrical member  7   e.    
         [0113]    In the seventh and eighth embodiments, the cartridge has a photosensitive drum, and the “external electrical connector” of the cartridge is the drum shaft  63  or external electrical connector  14 , which is electrically conductive. Further, the photosensitive drum is rotatably supported by the drum shaft  63  or external electrical connector  14 , with the presence of the flange  41  or  42  between the cylindrical member  7   e  and drum shaft  63  or external electrical connector  14 . This structural arrangement makes it possible for the drum shaft  63  or external electrical connector  14  to support the photosensitive drums  7 ,  207 ,  307 ,  407 ,  507 ,  1507 ,  607 ,  707 , and  808  while functioning as an electrical connector. Further, this structural arrangement makes the point of contact between an electrical connector and a drum shaft or external electrical connector coincides with the axial line of the drum shaft or external electrical connector. Therefore, it can make a process cartridge and an image forming more stable in electrical connection than those in the other embodiments. 
         [0114]    The electrical connector  21 - 29  in the first to eighth embodiments, respectively, are compatible with the photosensitive drums  7 ,  207 ,  307 ,  407 ,  507 ,  1507 ,  607 ,  707 , and  807 . Further, these photosensitive drums are compatible with various cartridges such as the cartridge  101 , which are compatible with various image forming apparatuses such as the image forming apparatus  100 . The effects of the application of the electrical connector  21 - 29  to the various photosensitive drums, cartridges, image forming apparatuses are the same as those obtained in the first to eighth embodiments. 
         [0115]    Further, in the first to eighth embodiments, each electrical connector is structured so that it has two vertical portions. However, these embodiments are not intended to limit the present invention in terms of the number of the vertical portions of an electrical connector. That is, the number of the vertical portions of an electrical connector may be three or more. 
         [0116]    As described above, according to the present invention, an electrical connector for an electrophotographic photosensitive drum, which contributes to the contact pressure between itself and the external electrical connector, is structured so that its first and second vertical portions, which function as springs, extend in the diameter direction of the photosensitive drum. Thus, not only can it be placed in the limited internal space of the cylindrical member of the photosensitive drum, but also, it is significantly longer, being therefore more stable in electrical connection (contact pressure), than a conventional electrical connector for an electrophotographic photosensitive drum. That is, the present invention can provide an electrical connector for an electrophotographic photosensitive drum, which is stable in the amount of contact pressure between its second portion of contact and an external electrical connector, and highly resistant to permanent deformation (plastic deformation). In other words, the present invention can provide an electrical connector for an electrophotographic photosensitive drum, which is significantly more stable in electrical connection than a conventional electrical connector for an electrophotographic photosensitive drum. 
         [0117]    While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims. 
         [0118]    This application claims priority from Japanese Patent Application No. 192104/2010 filed Aug. 30, 2010 which is hereby incorporated by reference.