Abstract:
A process cartridge detachable mountable to a main assembly of an electrophotographic image forming apparatus includes an electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on the photosensitive drum with developer; a transferring roller for causing transfer of the developer image from the photosensitive drum to a recording material; a cleaner, contacted to the photosensitive drum, for removing a developer remaining on the photosensitive drum; a developer accommodating portion for accommodating developer removed from the photosensitive drum by the cleaner; and a memory including a storing portion for storing predetermined information and a communicator for effecting wireless communication of the predetermined information stored in the storing portion with a main assembly side communicator provided in the main assembly of the electrophotographic image forming apparatus. The storing portion is disposed inside the developer accommodating portion and the storing portion is disposed on the same side of the process cartridge as the photosensitive drum with respect to tangent lines passing a contact point between the photosensitive drum and the developing roller or transfer roller.

Description:
This application is a divisional of U.S. patent application Ser. No. 09/671,649, filed Sep. 28, 2000, now U.S. Pat. No. 6,438,327, issued Aug. 20, 2002. 

   FIELD OF THE INVENTION AND RELATED ART 
   The present invention relates to a process cartridge and an electrophotographic image forming apparatus. In this specification, an electrophotographic image forming apparatus means such an apparatus that records images on recording media using an electrophotographic image formation system. The examples of electrophotographic image forming apparatuses include electrophotographic copying machines, electrophotographic printers (laser printers, LED printers, and the like), facsimile apparatuses, word processors, and the like. 
   A process cartridge is: a cartridge in which a charging means, a developing means or a cleaning means, and an electrophotographic photosensitive member, are integrally placed, and which is enabled to be removably installed in the main assembly of an image forming apparatus; a cartridge in which at least one among a charging means, a developing means, and a cleaning means, and an electrophotographic photosensitive member, are integrally placed, and which is enabled to be removably installed in the main assembly of an image forming apparatus; or a cartridge in which at least a developing means and an electrophotographic photosensitive member are integrally placed, and which is enabled to be removably installed in the main assembly of an image forming apparatus. 
   In the past, an electrophotographic image forming apparatus which employs an electrophotographic image forming process has been employing a process cartridge system, according to which an electrophotographic photosensitive member, and a single or plural processing means which act on the electrophotographic photosensitive member, are integrally placed in a cartridge removably installable in the main assembly of an image forming apparatus. This process cartridge system makes it possible for a user to maintain the apparatus without relying on maintenance personnel, drastically improving operational efficiency. Thus, the process cartridge system has been widely used in the field of image forming apparatuses. 
   A process cartridge is provided with an information storing means in which the history or specification values of the process cartridge are registered. The information storing means is enabled to communicate with the main assembly of an electrophotographic image forming apparatus so that the maintenance of the electrophotographic image forming apparatus main assembly and the process cartridge can be simplified or image quality can be improved. Some process cartridges are provided with a connector or the like which connects the electrophotographic image forming apparatus main assembly to the information storing means of the process cartridge. In order to eliminate the need for a mechanical connector which tends to increase the cartridge size, it has been considered to employ a noncontact communication system. 
   However, in the case of a process cartridge employing a wireless communication system, the aforementioned information storing means is affected by the electrical noises generated by the processing members, for example, a charge roller, a development sleeve, and a transfer roller of the apparatus main assembly, to which bias is applied from the electrophotographic image forming apparatus. Therefore, there is a chance that the contents of the information storing means will be destroyed or written over with erroneous information. 
   The present information is one of the results of the further development of the above described conventional technologies. 
   SUMMARY OF THE INVENTION 
   The primary object of the present invention is to provide a process cartridge enabled to wirelessly communicate with the main assembly of an electrophotographic image forming apparatus, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge capable of preventing the contents of the information storing means, which communicates with the main assembly of an electrophotographic image forming apparatus, from being destroyed or written over with erroneous information, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge in which an electrophotographic photosensitive drum is supported by a supporting means, and the information storing means is placed in the dead angle created by the electrophotographic photosensitive drum supporting means, as seen from any point on the linear interface between the charging means and the electrophotographic photosensitive means toward the photosensitive drum in a direction perpendicular to the longitudinal direction of the photosensitive drum, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge in which the information storing means is placed on the electrophotographic photosensitive drum side with respect to a plane, which is tangent to the peripheral surface of the electrophotographic photosensitive drum at the linear interface between the electrophotographic photosensitive drum and charging means, and is perpendicular to the longitudinal direction of the electrophotographic photosensitive drum, and also to provide an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge in which an information storing means is placed on the electrophotographic photosensitive drum side, with respect to a plane which is tangent to the peripheral surface of the electrophotographic photosensitive drum at the linear interface between the transferring means and electrophotographic photosensitive drum, and is perpendicular to the longitudinal direction of the electrophotographic photosensitive drum, and also to provide an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge in which the information storing means is placed on the electrophotographic photosensitive drum side, with respect to the plane which is tangent to the peripheral surface of the electrophotographic photosensitive drum at the linear interface between the electrophotographic photosensitive drum and developing means, and is perpendicular to the longitudinal direction of the electrophotographic photosensitive drum, and also to provide an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   Another object of the present invention is to provide a process cartridge in which the information storing means is placed outside a theoretical cylinder, the center line of which coincides with the axial line of the electrophotographic photosensitive drum, and which envelops the charging means, developing means, and transferring means, and also to provide an electrophotographic image forming apparatus in which such a process cartridge is removably installable. 
   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 an electrophotographic image forming apparatus in accordance with the present invention. 
       FIG. 2  is a sectional view of the process cartridge in the first embodiment of the present invention. 
       FIG. 3  is a sectional view of the process cartridge in the second embodiment of the present invention. 
       FIG. 4  is a sectional view of the process cartridge in the third embodiment of the present invention. 
       FIG. 5  is a sectional view of the process cartridge in the fourth embodiment of the present invention. 
       FIG. 6  is a sectional view of the process cartridge in the fifth embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, the preferred embodiments of the present invention will be described with reference to the appended drawings. 
   Embodiment 1 
   Referring to  FIGS. 1 and 2 , a process cartridge will be described along with an electrophotographic image forming apparatus in which a process cartridge is removably installable.  FIG. 1  is a sectional view of an electrophotographic image forming apparatus (laser beam printer) in which a process cartridge has been installed, and depicts the general structure of the apparatus.  FIG. 2  is a sectional view of a process cartridge, and depicts the general structure thereof. 
   As for the order of descriptions, first, the general structure of an electrophotographic image forming apparatus in which a process cartridge has been installed will be described, and then, the structure of a process cartridge will be described. 
   (General Structure) 
   Referring to  FIG. 1 , this electrophotographic image forming apparatus A (laser beam printer) is such an apparatus that forms an image on recording media (for example, recording paper, OHP sheet, fabric, and the like) with the use of an electrophotographic image formation process. In operation, it forms a toner image (developer image) on an electrophotographic photosensitive drum  7  (hereinafter, “photosensitive drum”) in the form of a drum. More specifically, the photosensitive drum  7  is charged by a charging means  8 , and then, the photosensitive drum  7  is exposed to a laser beam projected onto the photosensitive drum  7  from an optical means  1  while being modulated with image formation information, to form an electrostatic latent image in accordance with the image formation information, on the photosensitive drum  7 . The thus formed electrostatic latent image is developed into a toner image by a developing means  9 . 
   Meanwhile, a recording medium  2  having been placed in a cassette  3   a  is conveyed by a conveying means  3  comprising a pickup roller  3   b , a combination  3   c  of a feed roller and retard roller, two pairs  3   d  and  3   e  of conveying rollers, and the like, while being turned over, in synchronism with the toner image formation. Next, the toner image formed on the photosensitive drum  7  in the process cartridge B is transferred onto the recording medium  2  by applying voltage (transfer bias) to a transfer roller  4  as a transferring means with which the main assembly A 1  (hereinafter, “image forming apparatus main assembly”) of an electrophotographic image forming apparatus is provided. The transfer roller  4  comes into contact with the photosensitive drum  7  in such a manner that the linear interface between the two rollers becomes parallel to the longitudinal direction (axial line direction) of the photosensitive drum  7 , as the process cartridge B is installed into the image forming apparatus main assembly A 1 . 
   After receiving the toner image, the recording medium  2  is conveyed to a fixing means  5  by a conveyer belt  3   f . The fixing means  5  comprises a driver roller  5   a  and a rotational fixing member  5   b . The rotational fixing member  5   b  is a cylindrical sheet, and contains a heater. It is rotatably supported by a supporting member. The fixing means  5  applies pressure and heat to the recording medium  2  to fix the transferred toner image to the recording medium  2  while the recording medium  2  is passing through the fixing means  5 . 
   Thereafter, the recording medium  2  is conveyed through a reversing path, and discharged into a delivery tray  6 , by two pairs  3   g  and  3   h  of discharge rollers. The aforementioned optical means  1  comprises a laser diode, a polygon mirror, a lens, and a refection mirror, although they are not illustrated. 
   (Process Cartridge Structure) 
   The process cartridge B is such a cartridge that is provided with an electrophotographic photosensitive member, and at least one processing means. As for processing means, there are a charging means for charging an electrophotographic photosensitive member, a developing means for developing an electrostatic latent image formed on an electrophotographic photosensitive member, and a cleaning means for cleaning the toner particles remaining on the peripheral surface of an electrophotographic photosensitive member, for example. Referring to  FIG. 2 , in the process cartridge B in this embodiment, the photosensitive drum  7  with a photosensitive layer is rotated, and while it is rotated, its peripheral surface is uniformly charged by the voltage (charge bias) applied to a primary charge roller  8  (hereinafter, “charge roller”) as a charging means. Then, a laser beam modulated with the image formation information from the optical means  1  is projected upon the photosensitive drum  7  through an exposure opening (unillustrated) to form an electrostatic latent image. This electrostatic latent image is developed by the developing means  9  which uses toner. More specifically, the charge roller  8  is placed in contact with the photosensitive drum  7  in such a manner that the longitudinal axes of the two components become parallel to each other. As charge bias is applied to the charge roller  8  from the image forming apparatus main assembly A 1 , the photosensitive drum  7  is charged. The charge roller  8  rotates by following the rotation of the photosensitive drum  7 . The developing means  9  supplies the development region of the photosensitive drum  7  with toner to develop the electrostatic image formed on the photosensitive drum  7 . 
   The developing means  9  sends the toner within the toner container  11  toward a development sleeve  9   a  by the rotation of a toner conveying member  9   b . Further, it rotates the development sleeve  9   a , in which a stationary magnet is contained, and forms a layer of toner on the peripheral surface of the development sleeve  9   a , while triboelectrically charging the toner, by a development blade  9   d . The triboelectrically charged toner on the peripheral surface of the development sleeve  9   a  is supplied to the development region of the photosensitive drum  7 . The development sleeve  9   a  is provided with a pair of spacer rings  9   i  as a gap maintaining means, which are fitted one for one around the longitudinal (axial direction) end portions of the development sleeve  9   a , and remain in contact with the peripheral surface of the photosensitive drum  7  at the longitudinal ends of the photosensitive drum  7 , maintaining a predetermined distance between the peripheral surface of the development sleeve  9   a  and photosensitive drum  7 . In operation, development bias is applied from the image forming apparatus main assembly A 1  to the development sleeve  9   a  so that the toner on the development sleeve  9   a  is transferred onto the photosensitive drum  7  in accordance with the pattern of the aforementioned electrostatic latent image to form a toner image, or a visual image. The development blade  9   d  is a blade for regulating the amount of the toner on the peripheral surface of the development sleeve  9   a , as well as for charging the toner. In the areas adjacent to the development sleeve  9   a , a toner stirring member  9   e  for recirculating the toner within the development chamber is rotatably mounted. 
   After the toner image formed on the photosensitive drum  7  is transferred onto the recording medium  2  by applying voltage (transfer bias) opposite in polarity to the toner image, to the transfer roller  4 , the toner particles remaining on the photosensitive drum  7  are removed by the cleaning means  10 . More specifically, the cleaning means  10  scrapes the toner particles remaining on the photosensitive drum  7 , down into the waste toner bin  10   c  by the rubber cleaning blade  10   a  attached to the longitudinal tip portion of a cleaning blade holding member  10   b . The cleaning blade holding member  10   b  is formed of a piece of electrically conductive plate, and holds the rubber cleaning blade  10   a  in such a manner that the rubber cleaning blade  10   a  extends in the longitudinal direction of the photosensitive drum  7 . 
   The process cartridge B in this embodiment comprises: a toner container  11  which stores toner, and has a toner conveying member  9   b ; a developing means container  12  which holds the developing means such as the development sleeve  9   a , development blade  9   d , and the like; a cleaning means frame  13  to which the photosensitive drum  7 , the cleaning means  10  such as the rubber cleaning blade  10   a , cleaning blade holding member  10   b , and the like, and the charge roller  8 , are attached. In assembling the process cartridge B, first, the toner container  11  and developing means container  12  are joined together, forming a developing means frame  15 , and then, the developing means frame  15  is integrated with the cleaning means frame, completing the process cartridge B, which is removably installable into the cartridge installing means of the image forming apparatus main assembly A 1  by an operator. 
   Referring again to  FIG. 1 , the cartridge installing means comprises a lid  16  which can be rotationally opened about an axis  16   a , and cartridge guiding members (unillustrated) located on the internal surfaces of the left and right side walls of the cartridge installation space, which can be exposed by opening the lid  16 . During the installation or removal of the process cartridge B, the guiding portions of the process cartridge B, which comprise bosses and ribs, engage with the cartridge installation guiding means on the image forming apparatus main assembly A 1  side and are guided thereby, so that the process cartridge B is installed into or removed from the image forming apparatus main assembly in the direction of an arrow mark A. 
   (Description of Electrical Contact Points) 
   The process cartridge B is provided with a charge bias contact point (unillustrated) for applying charge bias to the charge roller  8  from the image forming apparatus main assembly A 1 , a development bias contact point (unillustrated) for applying development bias to the development sleeve  9   a , and a ground contact point (unillustrated) for grounding the photosensitive drum  7 , which are placed at predetermined locations. The image forming apparatus main assembly A 1  is provided with a charge bias contact point member (unillustrated), a development bias contact point member (unillustrated), and a ground contact point member (unillustrated), which make electrical contact with the charge bias contact point, development bias contact point, and ground contact point, correspondingly, as the process cartridge B is inserted to a predetermined point in the aforementioned cartridge installation space. Thus, as the process cartridge B arrives at the predetermined point in the cartridge installation space by being guided by the installation guiding member of the image forming apparatus main assembly A 1 , the charge bias contact point makes electrical contact with the charge bias contact point member, the development bias contact point makes electrical contact with the development bias contact point member, and the ground contact point makes electrical contact with the ground contact point member. As a result, it becomes possible for the charge bias (compound bias comprising AC voltage and DC voltage) to be applied to the charge roller  8  from an unillustrated bias supplying source (electrical power source) of the image forming apparatus main assembly A 1  through the charge bias contact point member and charge bias contact point, and for the development bias to be applied to the development sleeve  9   a  from the above mentioned bias supplying source through the development bias contact point member and development bias contact point. Further, it becomes possible for the transfer bias to be applied to the transfer roller  4  from the aforementioned bias supplying source. 
   (Means for Preventing Bias Application Noise Reaching Information Storing Means) 
   Referring to  FIGS. 1 and 2 , the process cartridge B in this embodiment is provided with an information storing means  14  for communicating with the image forming apparatus main assembly A 1  in a noncontact manner, that is, wirelessly. The information storing means  14  is placed within the cleaning means frame  13 . As the process cartridge B is installed into the image forming apparatus main assembly A 1 , the information storing means  14  comes to face a communication antenna  15  as the communicating means in the image forming apparatus main assembly A 1 , being therefore enabled to communicate with the image forming apparatus main assembly A 1 . The information storing means  14  comprises an information storing portion  14   a  for storing predetermined information, and a communicating means  14   b  for communicating with the image forming apparatus main assembly A 1 , which are integrated. 
   In this embodiment, a wireless communication system based on electromagnetic induction is employed as a noncontact communication system. More specifically, a magnetic core integral with the information storing portion  14   a  of the information storing means  14  is used as the communicating means  14   b  on the process cartridge B side, and the image forming apparatus main assembly A 1  is provided with an inductor as the communicating means on the image forming apparatus main assembly A 1  side, so that the communication between the image forming apparatus main assembly A 1  and process cartridge B can be carried out by electromagnetic induction through the magnetic core. In operation, predetermined types of information, for example, service history or cartridge specification values, are registered in the information storing portion  14   a  of the information storing means  14 , so that the maintenance of the image forming apparatus main assembly A 1  or process cartridge B is simplified, and/or image quality is improved through the communication between the process cartridge B and image forming apparatus main assembly A 1 . 
   Referring to  FIG. 2 , the information storing means  14  is placed in a dead region P 1  (hatched region) created by the cleaning blade holding member  10   b , in terms of the electromagnetic waves radiating from any point on the linear interface P 11  between the charge roller  8  and photosensitive drum  7  in the direction intersecting (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 . This placement of the information storing means  14  is effective to make the cleaning blade holding member  10   b  shield the information storing means  14  from the noises created by the bias applied to the charge roller  8 , making it possible to prevent the information storing portion  14   a  of the information storing means from being affected by the above described noise; it is effective to prevent the information stored in the information storing portion  14   a  from being destroyed by the noise. In other words, since the information storing portion  14   a  is shielded by the cleaning blade holding member  10   b  from the effects of the noises generated by the charge bias applied to the charge roller  8 , the predetermined information stored in the information storing member  14   a  of the information storing means  4  is prevented from being destroyed or written over with erroneous information. Thus, it is possible to prevent the effects of the noises generated by the charge bias applied to the charge roller  8  that the information storing means  14  destroys the information stored therein, or erroneously operates. 
   Embodiment 2 
   In this embodiment, another example of a process cartridge in accordance with the present invention will be described. In this cartridge, in order to prevent the information storing means  14  from being affected by the noises caused by the charge bias applied to the charge roller  8  of the process cartridge B, the information storing means  14  is placed within the cleaning means frame  13 . The components in this cartridge similar to those in the process cartridge B in the first embodiment are given the same reference codes as those in the first embodiment. 
     FIG. 3  is a sectional view of the process cartridge in this embodiment. In this embodiment, the information storing means  14  is placed in a region P 2  (hatched region), which is on the photosensitive drum  7  side with respect to a plane L 1 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 22  between the charge roller  8  and photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , as shown in FIG.  3 . Since the information storing means  14  is placed in the region P 2  (hatched region), which is on the photosensitive drum  7  side with respect to a plane L 1 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 22  between the charge roller  8  and photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , the information storing means  14  is shielded by the photosensitive drum  7  from the noises generated by the charge bias applied to the charge roller  8 . More specifically, the photosensitive drum  7  is electrically connected to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point, and therefore, the noises from the charge bias are led to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point. of the photosensitive drum  7 . In other words, the noises which dissipate from the linear interface P 22  are blocked by the portion of the peripheral surface of photosensitive drum  7  in the region P 2  on the photosensitive drum  7  side with respect to the aforementioned plane L 1  tangent to the peripheral surface of the photosensitive drum  7  at the linear interface P 22 . With this arrangement, it is possible to prevent the problem that the predetermined information stored in the information storing portion  14   a  of the information storing means  14  is destroyed, or written over with erroneous information, by the effects of the noises from the charge bias applied to the charge roller  8 . Thus, it is possible to prevent the problem that the information storing means  14  is caused to destroy the information stored therein, or to erroneously operate, by the noises from the charge bias applied to the charge roller  8 . 
   Embodiment 3 
   In this embodiment, another example of a process cartridge in accordance with the present invention will be described. In this cartridge, in order to prevent the information storing means  14  from being affected by the noises caused by the transfer bias applied to the transfer roller  4  of the process cartridge B, the information storing means  14  is placed within the cleaning means frame  13 . The components in this cartridge similar to those in the process cartridge B in the first embodiment are given the same reference codes as those in the first embodiment. 
     FIG. 4  is a sectional view of the process cartridge in this embodiment. In this embodiment, the information storing means  14  is placed in a region P 3  (hatched region), which is on the photosensitive drum  7  side with respect to a plane L 2 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 33  between the transfer roller  4  and photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , as shown in FIG.  4 . Since the information storing means  14  is placed in the region P 3  (hatched region), which is on the photosensitive drum  7  side with respect to a plane L 2 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 33  between the transfer roller  4  and photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , the noises caused by the transfer bias applied to the transfer roller  4  are blocked by the photosensitive drum  7 . More specifically, the photosensitive drum  7  is electrically connected to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point, and therefore, the noises from the transfer bias are led to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point of the photosensitive drum  7 . In other words, the noises which dissipate from the linear interface P 33  are blocked by the portion of the peripheral surface of photosensitive drum  7  in the region P 3  on the photosensitive drum  7  side with respect to the aforementioned plane L 2  tangent to the peripheral surface of the photosensitive drum  7  at the linear interface P 33 . With this arrangement, it is possible to prevent the problem that the predetermined information stored in the information storing portion  14   a  of the information storing means  14  is destroyed, or written over with erroneous information, by the effects of the noises from the transfer bias applied to the transfer roller  4 . Thus, it is possible to prevent the problem that the information storing means  14  is caused to destroy the information stored therein, or to erroneously operate, by the noises from the transfer bias applied to the transfer roller  4 . 
   Embodiment 4 
   In this embodiment, another example of a process cartridge in accordance with the present invention will be described. In this cartridge, in order to prevent the information storing means  14  from being affected by the noises caused by the development bias applied to the charge roller  8  of the process cartridge B, the information storing means  14  is placed within the cleaning means frame  13 . The components in this embodiment similar to those the first embodiment are given the same reference codes as those in the first embodiment. 
     FIG. 5  is a sectional view of the process cartridge in this embodiment. In this embodiment, the information storing means  14  is placed in a region P 4  (hatched region), which is on the photosensitive drum  7  side with respect to a plane L 3 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 44  between the spacer ring  9   i  of the development sleeve  9   a  and the photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , as shown in FIG.  5 . Since the information storing means  14  is placed in the region P 4  (hatched region), which is on the photosensitive drum  7  side with respect to the plane L 3 , which is tangent to peripheral surface of the photosensitive drum  7  at the linear interface P 44  between the spacer ring  9   i  of the development sleeve  9   a  and the photosensitive drum  7 , and intersects (approximately perpendicular) the longitudinal direction of the photosensitive drum  7 , the noises caused by the development bias applied to the development sleeve  9   a  are blocked by the photosensitive drum  7 . More specifically, the photosensitive drum  7  is electrically connected to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point, and therefore, the noises from the development bias are led to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point of the photosensitive drum  7 . In other words, the noises which dissipate from the linear interface P 44  are blocked by the portion of the peripheral surface of photosensitive drum  7  in the region P 4  on the photosensitive drum  7  side with respect to the aforementioned plane L 3  tangent to the peripheral surface of the photosensitive drum  7  at the linear interface P 44 . Therefore, it is possible to prevent the problem that the predetermined information stored in the information storing portion  14   a  of the information storing means  14  is destroyed or written over with erroneous information, by the effects of the noises from the development bias applied to the development sleeve  9   a . Thus, it is possible to prevent the problem that the information storing means  14  is caused to destroy the information stored therein, or to erroneously operate, by the noises from the development bias applied to the development sleeve  9   a.    
   Embodiment 5 
   This embodiment, which will be described next, is a case in which the information storing means  14  is placed within the cleaning means frame  13  to prevent the information storing means  14  from being subjected to the effects of the noises generated by the charge bias applied to the charge roller  8  of the process cartridge B, the noises generated by the development bias applied to the development sleeve  9   a  of the process cartridge B, and the noises generated by the transfer bias applied to the transfer roller  4  of the image forming apparatus main assembly A 1 . The components in this embodiment similar to those in the first embodiment are given the same reference codes as those in the first embodiment. 
     FIG. 6  is a sectional view of the process cartridge in this embodiment. In this embodiment, the information storing means  14  is in a region P 5  (hatched region), that is, the region outside a theoretical cylinder P 55 , the axial line of which coincides with the rotational center (axial line) of the photosensitive drum  7 , and which is in contact with the peripheral surface of the photosensitive drum  7  and envelops all the processing members, that is, the transfer roller  4 , charge roller  8 , and development sleeve  9   a , to which bias is applied from the image forming apparatus main assembly A 1 . Since the information storing means  14  is placed outside the theoretical cylinder P 55 , the axial line of which coincides with the rotational center (axial line) of the photosensitive drum  7 , and which is in contact with the peripheral surface of the photosensitive drum  7  and envelops all the processing members to which bias is applied from the image forming apparatus main assembly A 1 , the noises generated by the transfer bias applied to the transfer roller  4 , the noises generated by the charge bias applied to the charge roller  8 , and the noises generated by the development bias applied to the development sleeve  9   a , are all blocked by the photosensitive drum  7 . More specifically, the photosensitive drum  7  is electrically connected to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point, and therefore, the noises generated by the transfer bias, charge bias, and development bias, at the-linear interface P 22  between the photosensitive drum  7  and transfer roller  4 , the linear interface P 33  between the photosensitive drum  7  and charge roller  8 , and the linear interface P 44  between the photosensitive drum  7  and development roller  9   a , correspondingly, are led to the ground contact point member of the image forming apparatus main assembly A 1  through the ground contact point of the photosensitive drum  7 . In other words, the noises which dissipate from the linear interface P 22  between the photosensitive drum  7  and transfer roller  4 , the linear interface P 33  between the photosensitive drum  7  and charge roller  8 , and the linear interface P 44  between the photosensitive drum  7  and development roller  9   a , correspondingly, are blocked by the portion of the peripheral surface of the photosensitive drum  7  at and in the adjacencies of the linear interfaces P 22 , P 33 , and P 44 , within the theoretical cylinder P 55 . Therefore, it is possible to prevent the problem that the predetermined information which the information storing portion  14   a  of the information storing means  14  stores is destroyed or written over with erroneous information by the effects of the noises generated by the biases applied to the aforementioned processing members. Thus, it is possible to prevent the problem that the information storing means  14  is caused by the effects of the noises generated by the biases applied to the processing members, to destroy the contents of the information storing portion  14   a , or to erroneously operate. 
   Miscellaneous Embodiments 
   The process cartridges in the preceding embodiments were for forming a monochromatic image. However, the present invention is also applicable, with excellent results, to a process cartridge which is enabled to form a multicolor image (for example, two tone image, three tone image, or full-color image) with the provision of a plurality of developing means. 
   The selection of the electrophotographic photosensitive member does not need to be limited to the aforementioned photosensitive drum. For example, it may include the following. As for the photosensitive material, various photoconductors, for example, amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, as well as organic photoconductors, may be employed. As for the shape of the base member on which the photosensitive material is borne, it may be in the form of a drum or a belt, for example. In the case of a drum type photosensitive member, it is produced by depositing or painting photoconductor on the peripheral surface of a cylindrical base member formed of aluminum alloy or the like. 
   The definition of the aforementioned process cartridge, in other words, a cartridge to which the present invention is applicable, is such a cartridge that comprises, for example, an electrophotographic photosensitive member, and at least one processing means. In other words, in addition to the process cartridge referred to in the descriptions of the preceding embodiments, there are many process cartridges of various forms, to which the present invention is applicable; for example, a cartridge in which an electrophotographic photosensitive member and a charging member are integrally placed so that they can be removably installed in the apparatus main assembly, a cartridge in which an electrophotographic photosensitive member and a developing means are integrally placed so that they can be removably installed in the apparatus main assembly, a cartridge in which an electrophotographic photosensitive member and a cleaning means are integrally placed so that they can be removably installed in the apparatus main assembly, a process cartridge in which an electrophotographic photosensitive member and a combination of two or more among the aforementioned processing means are integrally placed so that they can be removably installed in the apparatus main assembly, and the like cartridges. 
   In other words, the definition of the aforementioned process cartridge is a cartridge which is removably installable in the image forming apparatus main assembly, and in which a charging means, a developing means or a cleaning means, and an electrophotographic photosensitive member, are integrally placed, a cartridge which is removably installable in the image forming apparatus main assembly, and in which at least one among a charging means, a developing means and a cleaning means, and an electrophotographic photosensitive member, are integrally placed, or a cartridge which is removably installable in the image forming apparatus main assembly, and in which at least a developing means and an electrophotographic photosensitive member are integrally placed. Thus, the apparatus main assembly can be maintained by a user himself or herself. 
   Further, in the preceding embodiments, a laser beam printer was referred to as an electrophotographic image forming apparatus. However, the application of the present invention does not need to be limited to a laser beam printer. Obviously, the present invention is also applicable to electrophotographic image forming apparatus of other forms, for example, electrophotographic copying machines, facsimile apparatuses, and word processors. 
   As described above, a process cartridge in accordance with the present invention can prevent the problem that the contents of the information storing means which wirelessly communicates with the electrophotographic image forming apparatus main assembly are destroyed or written over with erroneous information by the effects of the electrical noises generated by bias application. 
   An electrophotographic image forming apparatus in accordance with the present invention can removably accommodate a process cartridge in accordance with the present invention which can prevent the problem that the contents of the information storing means which wirelessly communicates with the electrophotographic image forming apparatus main assembly are destroyed or written over with erroneous information by the effects of the electrical noises generated by bias application. 
   While the invention has been described with reference to the structured 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.