Abstract:
A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus includes an electrophotographic photosensitive drum, a developing roller, a developer accommodator including two frames two end portion members, supporting the roller, a first member providing an electrostatic capacity between itself and the roller when a developing bias voltage is applied to the developing roller, and a second member including a contact portion elastically contacting to a bent portion of the accommodator, and a first electrical contact portion, electrically connected to the contact portion, for transmitting, to the main assembly, an electric signal corresponding to a value of the electrostatic capacity provided between the developing roller and the first member. The second member is mounted to one end portion member such that the contact portion is inside the one end portion member and the first electrical contact portion is outside the one end portion member.

Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to a process cartridge, and also, an electrophotographic image forming apparatus in which a process cartridge is removably mountable. 
     Here, a “process cartridge” is a cartridge in which an electrophotographic photosensitive member and processing means are integrally disposed, and which is removably mountable in the main assembly of an electrophotographic image forming apparatus. “Processing means” are means for processing an electrophotographic photosensitive member. One of the examples of a process cartridge is a cartridge in which an electrophotographic photosensitive member, and at least one processing means among a developing means, a charging means, and a cleaning means, are integrally provided. Another example of a process cartridge is a cartridge in which a charging means and cleaning means, which are processing means, and an electrophotographic photosensitive member, are integrally disposed. Further, there is a cartridge in which a developing means as the processing means, and an electrophotographic photosensitive member, are integrally disposed. 
     An “electrophotographic image forming apparatus” is an apparatus which forms an image on recording medium with the use of an electrophotographic image forming method. As examples of an apparatus which can be listed as an electrophotographic image forming apparatus, there are an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer, and son on.), a facsimile apparatus, a wordprocessor, and so on. 
     “Recording medium” is medium on which an image is formed. As examples of medium which may be listed as “recording medium,” there are a sheet of paper, OHP sheet, or the like. 
     The “main assembly” of an electrophotographic image forming apparatus is what remains after the removal of process cartridges from an electrophotographic image forming apparatus. 
     A process cartridge system has long been used in the field of an electrophotographic image forming apparatus. A process cartridge makes it possible for a use of an electrophotographic image forming apparatus to maintain the electrophotographic image forming apparatus on his or her own, that is, without relying on a service person. Thus, it can drastically improve an electrophotographic image forming apparatus in operational efficiency. 
     As for the electrical contact of a process cartridge, the one structured as follows has long been known. 
     That is, a process cartridge is made up of roughly two portions. On portion, which hereafter may be referred to as the first portion, is made up of a frame, and the components supported by the frame. The other portion, which hereafter may be referred to as the second portion, is also made up of a frame, and the components supported by the frame. The first and second portions are provided with the first and second electrical contacts, respectively. The first and second electrical contacts come into contact with each other as the frame of the first portion, and the frame of the second portions, are welded to each other. More specifically, the two electrical contacts come into contact with each other at the joint between the two frames. Further, in order to prevent toner from leaking through the joint between the two frames, the area of contact between the first and second electrical contacts is surrounded by an elastic sealing member (U.S. Pat. No. 6,571,070). 
     The above-described technology is very effective to ensure that the electrical contact of the first portion, and the electrical contact of the second portion, come into contact with each other, and remain in contact with each other. 
     SUMMARY OF THE INVENTION 
     The present invention is a further development of the above-described prior technology. 
     The primary object of the present invention is to a process cartridge whose electrically conductive first member, which extends inward, as well as the outward, of the developer storage portion of the process cartridge, is significantly better positioned in terms of special efficiency than the electrically conductive first member of a process cartridge in accordance with the prior art. 
     Another object of the present invention is to provide a process cartridge whose electrically conductive first and second members are ensured to make electrical connection with each other. 
     Another object of the present invention is to provide an electrophotographic image forming apparatus in which a process cartridge in accordance with the present invention is removably mountable. 
     Another object of the present invention is to ensure that the electrical contacts in a process cartridge make contact, and remain in contact, with their counterparts. 
     According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, said process cartridge comprising an electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum; a developer accommodating portion for accommodating the developer to be used for development of the electrostatic latent image by said developing roller, said developer accommodating portion including a first frame having an opening extended in a longitudinal direction of said developing roller for supplying accommodated developer to said developing roller, and a second frame mounted to said first frame by being bonded at a periphery thereof except for a non-bonding portion provided in a direction substantially perpendicular to the longitudinal direction at one longitudinal end portion; one end portion member, mounted to said one longitudinal end portion, for supporting one end of said developing roller; an another end portion member, mounted to the other longitudinal end portion of said developer accommodating portion, for supporting the other end of said developing roller; a first electroconductive member for providing an electrostatic capacity between itself and said developing roller when a developing bias voltage is applied to said developing roller, said first electroconductive member including an inner side portion provided on said second frame along the longitudinal direction and placed in said developer accommodating portion, and an outer side portion extending from the inner side portion through the non-bonded portion to an outside of said developer accommodating portion where said outer side portion is bent to provide a bent portion; and a second electroconductive member including a contact portion elastically contacting to said bent portion, and a first electrical contact portion, electrically connected to said contact portion, for transmitting, to the main assembly, an electric signal corresponding to a value of the electrostatic capacity provided between said developing roller and said first electroconductive member, wherein said second electroconductive member is mounted to said one end portion member such that contact portion is inside said one end portion member and that first electrical contact portion is outside said one end portion member. 
     According to another aspect of the present invention, there is provided an electrophotographic image forming apparatus to which said process cartridge is detachably mounting, said apparatus comprising a process cartridge including, a electrophotographic photosensitive drum, a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum, a developer accommodating portion for accommodating the developer to be used for development of the electrostatic latent image by said developing roller, said developer accommodating portion including a first frame having an opening extended in a longitudinal direction of said developing roller for supplying accommodated developer to said developing roller, and a second frame mounted to said first frame by being bonded at a periphery thereof except for a non-bonding portion provided in a direction substantially perpendicular to the longitudinal direction at one longitudinal end portion, one end portion member, mounted to said one longitudinal end portion, for supporting one end of said developing roller, an another end portion member, mounted to the other longitudinal end portion of said developer accommodating portion, for supporting the other end of said developing roller, a first electroconductive member for providing an electrostatic capacity between itself and said developing roller when a developing bias voltage is applied to said developing roller, said first electroconductive member including an inner side portion provided on said second frame along the longitudinal direction and placed in said developer accommodating portion, and an outer side portion extending from the inner side portion through the non-bonded portion to an outside of said developer accommodating portion where said outer side portion is bent to provide a bent portion, and a second electroconductive member including a contact portion elastically contacting to said bent portion, and a first electrical contact portion, electrically connected to said contact portion, for transmitting, to said main assembly, an electric signal corresponding to a value of the electrostatic capacity provided between said developing roller and said first electroconductive member, wherein said second electroconductive member is mounted to said one end portion member such that contact portion is inside said one end portion member and that first electrical contact portion is outside said one end portion member; and b) detecting means for detecting an amount of the developer of said process cartridge by an electric signal received from said first electrical contact portion. 
     These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of the image forming apparatus in the preferred embodiment of the present invention. 
         FIG. 2  is an enlarged sectional view of the cartridge in the preferred embodiment. 
         FIG. 3  is a perspective view of the cartridge in the preferred embodiment of the present invention, which shows the frame structure of the cartridge. 
         FIG. 4  also is a perspective view of the cartridge in the preferred embodiment of the present invention, which shows the frame structure of the cartridge. 
         FIGS. 5(   a ) and  5 ( b ) are perspective views of the cartridge compartment of the image forming apparatus in the preferred embodiment, as seen from the side from which the cartridge is driven, and the side from which the cartridge is not driven, respectively. 
         FIG. 6  is a perspective view of the developer storage container and its lid of the process cartridge, which is for showing the structure of the toner remainder amount detecting member. 
         FIG. 7  is a perspective view of one of the side covers of the toner storage container, and the corresponding lengthwise end portion of the storage container, of the process cartridge, which is for showing the structure of the contact portion of the toner remainder amount detecting member. 
         FIG. 8  is a perspective view of the portions of the cartridge having the electrically conductive first member and toner sealing member, which is for showing the structure of the toner sealing member. 
         FIG. 9  is a sectional view of the end portion of the toner storage container having the electrically conductive first member, after the welding of the toner storage container lid to the container. 
         FIGS. 10(   a )- 10 ( c ) are sectional views of the first portion of the process cartridge, which shows the relationship among the stirring member, toner conveying member, and toner remainder amount detecting member. 
         FIGS. 11(   a ) and  11 ( b ) are sectional views of the electrical contact of the toner remainder amount detecting member of the cartridge, and the portion of the toner storage container, after the attachment of the electrical contact to the toner storage container. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, the preferable embodiment of the present invention will be described with reference to the appended drawings. However, the functions, materials, and shapes of the structural components of the process cartridge and image forming apparatus in the preferred embodiment of the present invention, and the positional relationship among the structural components, are not intended to limit the present invention in scope, unless specifically noted. Further, once a given structural component (member) is described, it is the same in material, shape, etc., throughout this specification, unless specifically noted. 
     (General Structure) 
       FIG. 1  is a sectional view of the electrophotographic image forming apparatus  300 , in the preferred embodiment of the present invention, which is made up of the main assembly  1  of the image forming apparatus (which hereafter may be referred to simply as apparatus main assembly) and a process cartridge  2  (which hereafter may be referred to simply as cartridge).  FIG. 2  is an enlarged sectional view of the cartridge  2 . Next, referring to  FIGS. 1 and 2 , the overall structure of the image forming apparatus, and the image formation process of the image forming apparatus, will be described. The apparatus main assembly  1  is what remains after the removal of the cartridge  2  from the image forming apparatus  300 . 
     The electrophotographic image forming apparatus  300  in this embodiment is a laser beam printer made up of the main assembly  1 , and the cartridge  2  which is removably mountable in the main assembly  1 . The apparatus main assembly  1  is provided with an exposing apparatus  3  (laser scanner unit). The apparatus main assembly  1  is structured so that when the cartridge  2  is in its image forming position in the main assembly  1 , the exposing apparatus  3  is above the cartridge  2 . The apparatus main assembly  1  is also provided with a sheet tray  4  for holding sheets P of recording medium. The apparatus main assembly  1  is structured so that when the cartridge  2  is in its image forming position in the apparatus main assembly  1 , the sheet tray  4  is below the cartridge  2 . Further, the apparatus main assembly  1  is provided with a pickup roller  5   a , a pair of sheet conveyance rollers  5   b , two pairs of sheet conveyance rollers  5   c , a sheet transfer guide  6 , a transfer charge roller  7 , a sheet conveyance guide  8 , a fixing apparatus  9 , a pair of discharge rollers  10 , a delivery tray  11 , etc., which are positioned in the order in which they are listed. 
     (Description of Image Formation Process) 
     Next, the image formation process of this image forming apparatus will be described. First, a print start signal is to be inputted. As a print start signal is inputted, the electrophotographic photosensitive drum  20  (which hereafter will be referred to simply as drum  20 ) begins to be rotated in the direction indicated by an arrow mark R 1  at a preset peripheral velocity (process speed). The peripheral surface of the drum  20  is in contact with a charge roller  12  to which bias voltage is being applied. Thus, the peripheral surface of the drum  20  is uniformly charged to a preset potential level by the charge roller  12 . 
     A beam of laser light L is outputted from the exposing apparatus  3  while being modulated in accordance with the information regarding the image to be formed. More specifically, the beam of laser light L is projected into the cartridge  2  through an opening  53 , with which the top wall of the cartridge  2  is provided. As the beam of laser light L is projected into the cartridge  2 , it scans the charged portion of the peripheral surface of the drum  20 . As a result, an electrostatic latent image, which is in accordance with the information regarding the intended image, is formed on the peripheral surface of the drum  20 . This electrostatic latent image is developed by developer T (which hereafter may be referred to as toner), into a visible image, that is, an image formed of toner. The developer T is stored in a development unit  30 . 
     To describe in more detail, the charge roller  12  is in contact with the drum  20 , and charges the drum  20 . It is rotated by the rotation of the drum  20 . The development unit  30  develops the latent image on the drum  20 , by supplying the portion of the drum  20 , which is in the development area (station), with toner T. 
     The toner T is in a toner chamber  45 , that is, a developer chamber. A stirring member  43  sends the toner T into a toner supply chamber  44  by its rotation. In the toner supply chamber  44 , a development roller  41 , which internally holds a magnetic roller  41   a  (stationary magnet), is rotated. Thus, as the development roller is rotated, the toner in the toner supply chamber  44  is coated on the peripheral surface of the development roller  41  by a development blade  42 , while being frictionally charged. As a result, a layer of charged toner is formed on the peripheral surface of the development roller  41 . Then, the toner T is transferred from the development roller  41  onto the drum  20  in the pattern of the latent image on the drum  20 . As a result, an image which reflects the latent image is formed of toner T, on the peripheral surface of the drum  20 . That is, the development roller  41  develops the electrostatic latent image formed on the drum  20 , with the use of the toner T. The development blade  42  regulates the amount by which the toner T is coated on the peripheral surface of the development roller  41  per unit area, while frictionally charging the toner T. 
     The development unit  30  has the stirring member  43  and toner chamber  45 . 
     While a toner image is formed on the peripheral surface of the drum  20 , recording mediums P are fed by the pickup roller  5   a , from the sheet tray  4 , into the apparatus main assembly  1  in synchronism with the timing with which the aforementioned beam of light L is outputted. Then, the recording medium P is conveyed further into the apparatus main assembly  1  by the pair of sheet conveyance rollers  5   b , and the pairs of sheet conveyance rollers  5   c . Incidentally, the sheet tray  4  is in the bottom portion of the apparatus main assembly  1 . After being fed into the apparatus main assembly  1 , the recording medium P is conveyed by way of the transfer guide  6 , and then, is delivered to a transfer station, which is the interface between the drum  20  and transfer charge roller  7 . In the transfer station, the toner image is transferred from the drum  20  onto the recording medium P as if it were peeled away from the drum  20 . 
     After the transfer of the toner image onto the recording medium P, the recording medium P is separated from the drum  20 , and then, is conveyed to the fixing apparatus  9  along the conveyance guide  8 . Then, the recording medium P is conveyed through the nip (interface) between a fixation roller  9   a  and a pressure roller  9   b , of which the fixing apparatus  9  is made up. In this nip, the toner particles, of which the toner image is formed, are subjected to heat and pressure. As a result, the toner image becomes fixed to the recording medium P. After the fixation, the recording medium P is discharged into the delivery tray  11  by the pair of discharge rollers  10 . 
     After the transfer of the toner image from the drum  20 , the toner particles remaining on the peripheral surface of the drum  20  are removed by a cleaning blade  52 . Then, the cleaned portion of the peripheral surface of the drum  20  is used again for the above described image formation process, which begins with the charging step. The toner removed from the drum  20  is stored in a toner chamber  52   a  for the removed toner. 
     In the case of the electrophotographic image forming apparatus in this embodiment, the charge roller  12 , development roller  41 , and cleaning blade  52 , are the processing means for processing the drum  20 . 
     (Structure of Process Cartridge) 
       FIGS. 3 and 4  are perspective views of the process cartridge  2 , which are for describing the structure of the process cartridge  2 . 
     Next, referring to  FIGS. 2-4 , the cartridge  2  will be described about its structure. 
     Referring to  FIG. 2 , a drum unit  50  is made up of the drum  20 , charge roller  12 , cleaning blade  52 , and a drum unit frame  51 , to which the preceding components are integrally attached. 
     The development unit  30  is made up of a toner storage container  31  (first sub-frame) and a lid  32  (second sub-frame). It has the toner chamber  41  as a developer storage portion, and the toner supply chamber  44 . The toner storage container  31  and its lid  32  are integrated by welding or the like method. The development unit  30  is provided with an opening  31   a . Before the cartridge  2  is used for the first time by a user, the opening  31   a  remains sealed with a removable developer seal  47  (which hereafter may be referred to as toner seal); after the filling of toner storage container  31  with toner, the toner seal  47  is welded to the toner storage chamber  31  to seal the opening  31   a  to keep the toner sealed in the toner chamber  45 . 
     Before the cartridge  2  is used for the first time, more specifically, before the cartridge  2  is mounted into the apparatus main assembly  1  for the first time, the toner seal  47  is to be pulled out through a toner seal removal slot  62   c  in order to expose the opening  31   a . As the toner seal  47  is pulled out, the toner T in the toner chamber  45  is supplied to the area in which the development roller  41  is located. 
     As for the means for attaching the lid  32  to the toner storage container  31 , it does not need to be limited to welding. For example, the lid  32  and toner storage container  31  may be attached to each other by an adhesive, resin-to-resin bonding, or the two may be mechanically connected. Further, the means for attaching the toner seal  47  to the unit  30  does not need to be limited to welding. For example, it may be an adhesive or the like. 
     The toner storage container  31  is provided with a toner remainder amount detecting member  70  and a toner conveying member  46 . The toner remaining amount detecting member  70  may be referred to as the first electrically conductive member. The toner conveying member  46  is a piece of flexible sheet. The toner remainder amount detecting member  70  and toner conveying member  46  are within the toner chamber  45 . They are attached to the inward surface of the lid  32 , that is, the surface which will become the bottom surface of the toner storage container  31  as the cartridge  2  is mounted into its image forming position in the apparatus main assembly  1 . 
     As a development bias is applied to the development roller  41  from the apparatus main assembly  1  after the mounting of the cartridge  2  into the apparatus main assembly  1 , a certain amount of static electricity is induced between development roller  41  and toner remainder amount detecting member  70 . The amount of toner between the development roller  41  and toner remainder detecting member  70  changes with the consumption of the toner T. The dielectric constant of the toner T is greater than that of the air. Therefore, as the body of toner T in the development unit  30  changes in amount, it gradually changes in electrostatic capacity. Thus, the amount of the developer in the toner chamber  45  can be detected by sending electrical signals, which reflect the value of the abovementioned electrostatic capacity, to a detecting means  80  ( FIG. 1 ) with which the control portion  200  of the apparatus main assembly  1  is provided. 
     As for the choice of the detecting means  80 , any of the known detecting means may be employed as fits. 
     That is, if the amount of the toner T detected by the detecting means  80  is smaller than a preset value, it is displayed on a monitor portion  400  ( FIG. 1 ), with which the apparatus main assembly  1  is provided, that the amount of developer in the development unit  30  became smaller than a desirable one. This information may be displayed on the monitor (unshown) of a personal computer or the like, to which the printer is connected. Thus, a user can recognized by watching the monitor that the amount of the toner T in the toner chamber  45  has become smaller than a preset one. Thus, the user can prepare a brand-new cartridge  2 . 
     Regarding the display of the estimated amount of the toner in the toner chamber  45  on the abovementioned monitor portion of the printer, or monitor of the personal computer, the information on the monitor or the monitor portion is controlled by the electrical signals outputted by the control portion  200 , which receives electrical signals from the detecting means  80 . Further, the electrical signals which are outputted by the detecting member  70 , and which reflect the value of the abovementioned electrostatic capacity, are transmitted to the detecting means  80  through a contact point  70   c , a contact point  64   a , contact point  64   b , and a contact point  101 . The contact points  70   c ,  64   a , and  64   b  are the contact points of the process cartridge  2 . The contact point  101  is the contact point of the contact of the detecting means  80  of the apparatus main assembly  1 . 
     The detailed description of the toner remainder amount detecting member and toner conveying member will be given later. 
     Next, referring to  FIGS. 3 and 4 , the development unit  30  is provided with a pair of side covers  61  and  62 , which make up the lengthwise end portions of the unit  30  (in terms of direction parallel to axial line of development roller  41 ), one for one. The side covers  61  and  62  support bearing members (unshown), one for one, by which the development roller  41  is rotatably supported. 
     The side covers  61  and  62  are provided with arm portions  61   a  and  62   a , respectively, whose end portions have a through hole  61   b  (which is round in cross section) and a through hole  62   b  (which is oval in cross section), respectively. The drum unit frame  51  is provided with holes  51 R and  51 L for a pair of connective member  54 , one for one, which are positioned so that as the drum unit  50  and development  30  unit are positioned in such a manner that the arm portions  61   a  and  62   a  fit into preset portions of the drum unit frame  51 , the holes  61   b  and  62   b  of the arm portions  61   a  and  62   a  align with the holes  51 R and  51 L of the frame of the development unit  30 , respectively. Thus, as the connective members  54  are put through the holes  61   b ,  51 R,  51 L, and  62   b , the units  50  and  30  become connected to each other in such a manner that they are allowed to rotationally move relative to each other about the connective members  54 . With the two units  50  and  30  being connected as described above, a pair compression springs  63  attached to the base portions of the arm portions  61   a  and  62   a , respectively, remain in contact with the drum unit frame  51  and keep the unit  30  pressed downward. Therefore, it is ensured that the development roller  41  ( FIG. 2 ) is kept pressed toward the drum  20 . Since the lengthwise end portions of the development roller  41  are fitted with a pair of gap maintaining members (unshown), one for one, the development roller  41  is held with the presence of a preset amount of gap from the drum  20 . That is, the gap maintaining members (unshown) maintain the preset amount of gap (roughly 300μ) between the development roller  41  and drum  20  by remaining in contact with the drum  20 . 
     Further, one of the lengthwise ends of the unit  50  is provided with a coupling member  150  for rotating the drum  20  by receiving driving force from the apparatus main assembly  1 . Referring to  FIG. 4 , the side cover  62  holds the electrical contact  64  of the toner remainder amount detecting member, and the electrical contact  65  for applying voltage to the development roller  41 . Further, the side cover  62  has a slit  62   c , through which the toner seal  47  is pulled out by a user. 
     Prior to the first time usage of the cartridge, one of the lengthwise end portions of the toner seal  47  remains exposed from the cartridge  2  through the slit  62   c  so that when a brand-new cartridge  2  is used for the first time, the toner seal  47  can be pulled out by a user. 
     With the provision of the above described structural features, it is possible to obtain the process cartridge  2  whose units  50  and  30  are integrally connected to each other in such a manner that the two units  50  and  30  are allowed to rotationally move relative to each other. 
     Next, the apparatus main assembly  1  will be described. 
     Referring to  FIGS. 5(   a ) and  5 ( b ), the apparatus main assembly  1  is provided with a cartridge mounting means  130 , which is made up of a pair guiding rails for guiding the cartridge  2  when the cartridge  2  is mounted into the apparatus main assembly  1  or removed from the apparatus main assembly  1 . The cartridge  2  is to be mounted into the apparatus main assembly  1  by a user along the cartridge mounting means  130  while remaining held by the user. As the cartridge  2  is mounted into the apparatus main assembly  1 , the coupling member  150 , which is the rotational force transmitting component of the cartridge  2 , couples with a drive shaft  100  with which the apparatus main assembly  1  is provided, making it possible for the drum  20  to be rotated by the driving force from the apparatus main assembly  1 . The drive shaft  100  and coupling member  150  are structured so that the coupling member  150  can couple with the drive shaft  100  from the direction which is virtually perpendicular to the axial line of the drive shaft  100 , and also, so that when removing the cartridge  2  from the apparatus main assembly  1 , the coupling member  150  can be uncoupled from the drive shaft  100  in the abovementioned direction. The drum  20  and development roller  41  are rotated by the rotational force received by the coupling member  150  from the drive shaft  100 . 
     While the cartridge  2  is in its image forming position in the apparatus main assembly  1 , the electrical contact  64  of the cartridge  2  remains in contact with the electrical contact  101  of the apparatus main assembly  1 , and the development contact  65  of the cartridge  2  remains in contact with the development contact  102  of the apparatus main assembly  1 . Therefore, voltage can be applied to the cartridge  2  from the apparatus main assembly  1 . 
     (Structure of Toner Remainder Amount Detecting Member and its Adjacencies) 
     Referring to  FIG. 6 , the surface  32   a  of the lid  32  is the surface which comes into contact with the toner storage container  31  as the lid  32  is attached to the toner storage container  31 . It is provided with a welding rib  32   b  for welding the lid  32  to the container  31 . The welding rib  32   b  is almost as long as the contacting surface  32   a ; the welding rib  32   b  has a gap  32   c . The toner storage container  31  is provided with a lid contacting surface  31   b , which comes into contact with the welding rib  32   b  as the lid  32  is attached to the container  31 . 
     In this embodiment, the toner storage container  31  and lid  32  are joined by welding. However, the two may be joined with an adhesive, as described before. 
     The cartridge  2  in this embodiment has the toner remainder amount detecting means for detecting the amount of the toner T remaining in the toner storage container  31 . The amount of the toner T remaining in the toner storage container  31  is detected by the detecting means  80  with which the apparatus main assembly  1  is provided. 
     Referring to  FIG. 6 , the toner remainder amount detecting member  70  is made up of a piece of metallic plate. More concretely, the detecting means  70  has a detecting portion  70   a , an intermediary portion  70   b , and a contact portion  70   c . The detecting portion  70   a  is the portion within the toner chamber  45 , and the intermediary portion  70   b  is the portion between the detecting portion  70   a  and contact portion  70   c . The contact portion  70   c  is the portion that extends outward from the intermediary portion  70   b . It is slightly bend. The toner remainder amount detecting portion  70   a  is firmly attached to the lid  32  with a piece of two-sided adhesive tape (unshown). 
     The detecting member  70  is attached to the lid  32  in such a manner that its lengthwise direction is parallel to the lengthwise direction of the development roller  41 , and also, that its intermediary portion  70   b  coincides in position to the gap  32   c . The intermediary portion  70   b  is held to the portion of the lid  32 , which corresponds in position to the gap  32   c  of the welding rib  32   b , with a bonding means  72  such as a piece of two-sided adhesive tape. Further, the toner remainder amount detecting member  70  is bent toward the toner storage container  31 , at the border between the detecting portion  70   a  and intermediary portion  70   c , in such a manner that after the welding of the lid  32  to the container  31 , the contact portion  70   c  faces a trapezoidal protrusion  31   d , which is on the outward side of the lengthwise end of the container  31 . 
     The container  31  is provided with a toner sealing member  71 , which is an elastic sealing member formed of foamable substance. The toner sealing member  71  is attached to the container  31  with the use of a piece of two-side adhesive tape or the like, in such a manner than its overlaps with the intermediary portion  70   b  of the toner remainder amount detecting member  70 . 
     The lid  32  is provided with a sheet as the toner conveying member  46 . This sheet  46  is fixed to the lid  32 , by its edge which corresponds in position to the top edge of the slanted surface of the lid  32 , by thermal crimping, or with the use of a piece of two-side adhesive tape or the like. 
     Incidentally, in this embodiment, two-sided adhesive tape is used as the bonding means. However, as long as the above described members, portions, etc., can be satisfactorily bonded, the bonding means does not need to be two-sided adhesive tape. 
     The container  31  and lid  32  are welded to each other using the following method. First, the components which are to be placed in the toner chamber  45  are attached to the inward side of the toner chamber  45 . Then, the container  31  is fitted with the lid  32  so that the flange portion  31   c  of the container  31  catches the flange portion  32   f  ( FIG. 30 ) of the lid  32 . Then, ultrasonic vibrations are transmitted to the rib  32   b  of the lid  32  while keeping the flange portions  31   c  and  32   f  cramped together so that the rib  32   b  is melted by the frictional heat, and welds itself to the bonding surface  31   b  of the container  31 , except for the gap portion  32   c . That is, the container  31  and lid  32  are integrated by the bonding. Because the lid  32  is welded to the container  31  while the flange portion  31   c  of the container  31  and the flange portion  32   f  of the lid remaining cramped together, the toner sealing member  71  remains compressed in a manner to conform in shape to the gap formed by the container  31  and lid  32 . 
     The toner chamber  45  (developer storage portion) stores the developer T, which is used for developing the above described electrostatic latent image, by the development roller  41 . Further, the toner chamber  45  has the toner storage container  31  (first sub-frame portion) and the lid  32  (second sub-frame portion). It also has a hole  31   a  through which the developer T in the container  31  is supplied to the development roller  41 . The hole  31   a  extends in the direction parallel to the lengthwise direction of the development roller  41 , from one end of the container  31  to the other. Further, the lid  32  remains attached to the container  31  by being bonded to the container  31  by its flange portion which surrounds the lid  31 , except for the gap portion  32   c  provided at one of the lengthwise end of the lid  31 . Incidentally, the gap  32   c  is provided by the lid  32 . 
     Next, referring to  FIG. 7 , the side cover  62  holds the toner remainder amount detection electrical contact  64  and a development electrical contact  65 . The detection contact  64  is the electrically conductive second member of the cartridge, and the development contact  65  is the electrically conductive third member of the cartridge  2 . The contact  64  has a portion  64   a  and a portion  64   b . The portion  64   a  contacts the contact portion  70   c  (bend portion) of the detecting member  70 . The portion  64   b , which is the first electrical contact of the cartridge  2 , contacts the electrical point  101  ( FIG. 5 ) of the main assembly  1 . The detection contact  64  is attached to the side cover  62  in such a manner that the contact portions  64   a  and  64   b  are on the inward and outward sides, respectively, of the side cover  62 . 
     Further, the contact  65  has a contact point  65   a  and a second electrical contact  65   b . The contact point  65   a  contacts a development roller electrode  41   b , which is electrically in contact with the development roller  41 . The second electrical contact point  65   b  receives development bias by contacting the development contact  102  ( FIG. 5 ) of the apparatus main assembly  1 . 
     The toner storage container  31  is provided with a pair of side cover anchoring receptacles  31   e , whereas the side cover  62  is provided with a pair of side cover anchoring projections  62   d . Thus, the side cover  62  is solidly attached to the toner storage container  31  with the use of resin, smaller screws, or the like means, with the side cover anchoring projections  62   d  of the side cover  62  fitted in the side cover anchoring receptacles  31   e  of the toner storage container  31 , one for one. 
       FIG. 11  is a sectional view of the contact ( 64 ) anchoring portion  62   c  of the toner storage container  31 . 
     Referring to  FIG. 11(   a ), in a case where the side cover  62  is solidly attached to the container  31  by bonding, first, the contact  64  is placed on the side cover  62  in such a manner that the anchoring projections  62   d  of the side cover  62  fit into the through holes  64   c  with which the contact  6  is provided. Then, the side cover  62  is fixed to the container  31  by injecting resin J (hatched area in  FIG. 11(   a )) between the anchoring projection  62   d  and container  31 , so that the contact  64  becomes solidly attached to the container  31  by being sandwiched between the side cover  62  and container  31 . The contact  64  is shaped like a leaf spring whose free end constitutes the contact point  64   a . Thus, the contact point  64   a  is kept in contact with the contact point  70   c  of the detecting member  70  by the elasticity of the contact  64  (leaf spring). 
     The above described structural arrangement ensures that the contact point  64   a  of the contact  64  remains in contact with the contact point  70   c  of the detecting member  70 . 
     On the other hand, referring to  FIG. 11(   b ), in a case where the side cover  62  is solidly attached to the container  31  with the use of small screws, a small screw  66  is put through the through hole  64   c  of the contact  64 . Also in this case, the contact  64  is solidly attached to the container  31  by being sandwiched between the side cover  62  and container  31  as it is in the case where resin is used as the means for securely holding the contact  64 . 
     The side cover  62  and container  31  are structured so that whether the side cover  62  is attached to the container  31  with the use of resin or small screws, the anchoring portion  62   d  presses the adjacencies of the base portion of the contact  64  (leaf spring) whose tip portion is the contact point  64   a . Thus, this structural arrangement makes it possible to prevent the problem that the contact  64  is dislodged by the pressure which the contact  64  receives. That is, it ensures that the contact pressure remains stable. 
     Next, referring to  FIGS. 8 and 9 , the toner sealing portion will be described. 
       FIG. 8  is a perspective view of the toner remainder amount detecting member  70  and toner sealing member  71  before the welding of the lid  32  to the container  31 .  FIG. 9  is a sectional view of the toner remainder amount detecting member  70  and toner sealing member  71  after the welding of the lid  32  to the container  31 . The intermediary portion  70   b  of the detecting member  70  is fixed to the lid  32  with the use of a piece of two-sided adhesive tape. The sealing member  71  is bonded to the container  31 . Further, after the welding of the lid  32  to the container  31 , the sealing member  71  remains compressed in its thickness direction, and therefore, the detecting member  70  remains sandwiched between the two-sided adhesive tape and sealing member  71 . That is, the sealing member  7  keeps sealed the outward toner passage from the toner chamber  45 . That is, the presence of the sealing member  71  prevents the toner in the toner chamber  45  from leaking outward. The contact point  70   c  of the detecting member  70  remains pressed by the contact  64  of the side cover  62 , in the direction indicated by an arrow mark S. The container  31  is provided with the trapezoidal protrusion  31   d , which is positioned so that it can back up the detecting member  70  against the contact pressure. That is, the protrusion  31   d  prevents the contact point  70   c  from being excessively flexed by the contact pressure. In other words, the trapezoidal protrusion  31   d  prevents the contact point  70   c  from collapsing. 
     Not only can the above described structure arrangement make it possible to better seal the toner storage container  31 , but also, to stabilize the contact pressure between the toner remainder amount detecting member  70  and contact  64 . 
     (Description of Structure of Stirring means) 
       FIG. 10  is a sectional view of the development unit  30 . 
     As described above, the flexible sheet  46 , which is a member for conveying toner, is on the bottom surface of the toner chamber  45 , that is, the inward surface of the lid  32 . It is positioned so that the edge portion of the sheet  46 , which is on the toner outlet side, overlaps with the top edge portion of the detecting member  70 , in terms of the vertical direction. 
     When the cartridge  2  is in its image forming position in the apparatus main assembly  1 , the first surface  32   d  of the toner chamber  45 , which is holding the detecting member  70 , inclines downward from the second surface  32   e , by which the sheet  46  is held. Further, the edge portion  46   a  ( FIG. 10 ) of the sheet  46 , which is on the toner outlet side, projects beyond the second surface  32   e.    
       FIG. 10(   a ) shows, in cross section, the development unit  30  immediately before the sweeping edge portion  42   a  of the stirring member  43  comes into contact with the sheet  46 . Next, referring to  FIG. 10(   b ), as the stirring member  43  rotates, it causes the sweeping edge portion  42   a  of the stirring member to flex. Thus, as the stirring member  43  rotates further, the edge portion  46   a  of the sheet  46  snaps back. As a result, the edge portion  46   a  of the sheet  46  (toner conveying member) vibrates, making it easier for the toner on the sheet  46  to slide downward on the sheet  46 . Next, referring to  FIG. 10(   c ), as the stirring member  43  rotates further after it allowed the edge portion  46   a  of the sheet  46  to snap back, the edge portion  46   a  of the sheet  46  sweeps (rubs) the inward surface of the detecting member  70 . 
     The above described structural arrangement for the cartridge  2  makes it possible to provide a process cartridge  2 , which is significantly smaller in the angle of the lid  32  relative to the horizontal direction when the cartridge  2  is in the image forming position in the apparatus main assembly  1 , than a cartridge in accordance with the prior art, that is, a cartridge  2  in which the sheet  46  is not present. In other words, the above described structural arrangement for the cartridge  2  makes it possible to more efficiently use the internal space of the toner chamber  45 . Further, it makes the edge portion  46   a  of the sheet  46  overlap with the top edge portion of the detecting member  70 . Therefore, it makes it possible to provide a process cartridge which is smaller in the area in which the edge portion of the detecting member  70  rubs against toner, being therefore smaller in the amount of toner deterioration than a cartridge in accordance with the prior art. 
     The above described structural arrangement for the cartridge  2  in this embodiment can be summarized as follows: 
     (1) The cartridge  2  is removably mountable in the main assembly  1  of an image forming apparatus  300 . The cartridge  2  has: the drum  20 ; development roller  41  for developing an electrostatic latent image formed on the drum; and toner chamber  45  (developer storage) in which the developer T to be used for the development of the electrostatic latent image is stored. The toner chamber  45  has the toner storage container  31  (first sub-frame portion), which has the long and narrow hole  31   a , which is provided for supplying the development roller  41  with the developer T stored in the toner chamber  45 , and which extends in parallel to the development roller  41 , virtually from one end of the toner chamber  45  to the other. Further, the toner chamber  45  has the lid  32  (second frame portion), which is bonded to the container  31  by its peripheral portion (flange-like portion), except for the gap  32   c  of the welding rib  32   b , which is at one of the lengthwise ends of the lid  32 . 
     Further, the cartridge  2  has: the side cover  62 , which is attached to one of the lengthwise ends of the toner chamber  45  to support one end of the development roller  41 ; and the side cover  61  attached to the other lengthwise end of the toner chamber  45  to support the other end of the development roller  41 . Further, the cartridge  2  has the electrically conductive first member  70 , which is for generating static electricity between itself and development roller  41  as development bias is applied to the development roller  41 . 
     The electrically conductive member  70  is attached to the lid  32  (second sub-frame portion) in such a manner that its lengthwise direction becomes parallel to the abovementioned lengthwise direction. The electrically conductive member  70  has: the inward portion  70   a , which is inside the toner chamber  45 ; intermediary portion  70   b , which extends from the inward portion  70   a  to the outward surface of the toner chamber  45  through the gap  32   c ; and outward portion  70   c , which is slightly bent portion and extends roughly perpendicularly from the outward end of the intermediary portion  70   c.    
     Further, the cartridge  2  has the electrically conductive second member  64  (second contact). The electrically conductive second member  64  has: the contact point  64   a , which is kept in contact with the outward portion  70   c  of the electrically conductive member  70  by the elasticity of the conductive member  70 ; and electrically conductive first contact point  64   b , which is in electrical connection to the contact point  64   a . The contact point  64   b  is for transmitting to the apparatus main assembly  1 , electrical signals which reflect the amount of static electricity generated between the development roller  41  and electrically conductive member  70 . Further, the contact  64  is attached to the side cover  62  in such a manner that the contact points  64   a  and  64   b  are positioned on the inward and outward sides, respectively, of the side cover  62 . 
     The above described structural arrangement makes it possible to simplify in structure the contacts, which extend from the inward side of the toner chamber  45  to the outward side. Therefore, it can reduce the cartridge  2  in cost. 
     (2) The portion of the electrically conductive member  70 , which corresponds in position to the gap  32   c , is pasted to the lid  32 , with the use of a piece of two-sided adhesive tape  72  (bonding member). Further, this portion of the electrically conductive member  70  is held to the toner chamber  45  by being sandwiched between the piece of two-sided adhesive tape  72 , and the elastic sealing member  71  attached to the container  31 . 
     Thus, not only did the usage of the above described structural arrangement make it possible to simplify the electrical contacts in structure, but also, to better seal the cartridge  2  in terms of toner leakage. 
     (3) The bent portion  70   c  of the electrically conductive member  70  faces the trapezoidal protrusion  31   d , which is on one of the lengthwise outward end surfaces of the toner chamber  45 . Thus, as the contact point  64   a  is pressed upon the bent portion  70   c , the bent portion  70   c  comes into contact with the protrusion  31   d . That is, the protrusion  31   d  prevents the bent portion  70   c  from being flexing beyond where the protrusion  31   d  is. 
     The usage of this structural arrangement made it possible to minimize the fluctuation of the contact pressure between the electrically conductive member  70  and contact  64 . Thus, it made it possible to provide a process cartridge which is reliable in terms of the electrical connection between its electrically conductive member  70  and contact  64 . 
     (4) The side cover  62  holds the electrically conductive third member  65 , which has the second electrical contact point  65   a  for receiving the development bias to be applied to the development roller  41  from the apparatus main assembly  1  when the cartridge  2  is in the image forming position in the apparatus main assembly  1 . 
     This structural arrangement uses only the side cover  62  to precisely position the electrically conductive members  64  and  65 . Therefore, it can minimize the fluctuation of the electrostatic capacity between the electrically conductive members  64  and  65 , and therefore, can provide a process cartridge  2  capable of detecting the amount of the toner remainder therein at a significantly higher level of accuracy than a process cartridge in accordance with the prior art. 
     (5) The cartridge  2  is provided with the removable toner seal  47  (developer seal) for sealing the hole  31   a . Further, the side cover  62  is provided with the hole  62   c , through which one of the lengthwise ends of the toner seal  47  is extended outward from the cartridge  2  to allow a user to pull the toner seal  47  out of the cartridge  2  before the cartridge  2  is used for the first time. 
     Providing the cartridge  2  with the removable toner seal  47  made it possible to keep the cartridge  2  better sealed before the cartridge  2  is used for the first time. 
     (6) The cartridge  2  is provided with the stirring member  43  which is rotated for stirring the developer T in the toner chamber  45 . The stirring member  43  rubs the inwardly facing surface  70   a  of the electrically conductive member  70 . 
     This structural arrangement made it possible to reduce the amount by which the toner remains on the detecting member  70 , and therefore, made it possible to provide a process cartridge capable of detecting the amount of the toner remainder therein at a significantly higher level of accuracy than a process cartridge in accordance with the prior art. 
     (7) The cartridge  2  and apparatus main assembly  1  are structured so that when the cartridge  2  is in its image forming position in the apparatus main assembly  1 , the lid  32  faces downward. Further, the cartridge  2  is provided with the flexible sheet  46 , which partially overlaps with a part  70   a  of the electrically conductive member  70 , in terms of the vertical direction, when the cartridge  2  is in its image forming position in the apparatus main assembly  1 . 
     This structural arrangement can prevent the stirring member  43  from directly rubbing the part  70   a  of the electrically conductive member  70 , and therefore, can reduce the amount by which the toner is deteriorated. 
     (8) The cartridge  2  and apparatus main assembly  1  are structured so that when the cartridge  2  is in its image forming position in the apparatus main assembly  1 , the first surface  32   d , which holds the electrically conductive member  70 , extends diagonally downward from the second surface  32   e , which holds the flexible sheet  46 . Further, the bottom edge portion  46   a  of the sheet  46  extends beyond the second surface  32   e . Thus, when the stirring member  43  rotates, the sweeping edge portion  42   a  of the stirring member  43  causes the sheet  46  to vibrate, by coming into contact with the bottom edge portion  46   a  of the sheet  46 . Further, the sweeping edge portion  42   a  of the stirring member  43  rubs the surface of the inward portion  70   a  of the electrically conductive member  70 . 
     This structural arrangement makes it possible for the toner to be conveyed even if the angle of the second surface  32   e  is significantly smaller than the angle of the counterpart in a cartridge in accordance with the prior art. That is, it makes it possible to more efficiently use the internal space of a cartridge. Therefore, this structural arrangement makes it possible to provide an electrophotographic image forming apparatus  300  which is significantly smaller than an electrophotographic image forming apparatus  300  in accordance with the prior art. 
     (9) The main assembly  1  of the electrophotographic image forming apparatus  300  has the detecting means  80  ( FIG. 10 ) for detecting the amount of the developer in the cartridge  2 , based on the electrical signals received from the first portion  64   b  of the electrical contact  64 . Therefore, the amount of the developer in the cartridge  2  can be detected by the apparatus main assembly  1 , based on the electrical signals sent from the cartridge  2 . 
     According to the preferred embodiment described above, the electrically conductive first member of a process cartridge, which is to extend from the inward side of the development unit of the process cartridge to the outward side of the development unit, can be more efficiently attached to the development unit, in terms of spatial efficiency, compared to the counterpart of a process cartridge in accordance with the prior art. 
     Further, according to the preferred embodiment, it is possible to ensure that the electrically conductive first and second members make contact, and remain in contact, with each other. 
     Also according to the preferred embodiment described above, it is possible to ensure that the contact points in a process cartridge make contact, and remain contact, with the counterparts. 
     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. 
     This application claims priority from Japanese Patent Application No. 198424/2008 filed Jul. 31, 2008 which is hereby incorporated by reference.