Patent Publication Number: US-9429908-B2

Title: Connector, process cartridge, and image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2014-245953 filed Dec. 4, 2014. 
     BACKGROUND 
     Technical Field 
     The present invention relates to connectors, process cartridges, and image forming apparatuses. 
     SUMMARY 
     According to an aspect of the invention, there is provided a connector including a first connector member and a second connector member. The first connector member retains an integrated circuit having multiple first electrodes in a secured state and is externally contactable with the multiple first electrodes. The second connector member is attachable to and detachable from the first connector member and has a connection unit that is directly connected to the multiple first electrodes of the integrated circuit when the first connector member is attached to the second connector member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  illustrates the overall configuration of an image forming apparatus according to a first exemplary embodiment of the present invention; 
         FIG. 2  illustrates the configuration of an image forming section of the image forming apparatus according to the first exemplary embodiment of the present invention; 
         FIG. 3  is a perspective view illustrating a relevant part of a process cartridge; 
         FIG. 4  is a perspective view illustrating a relevant part of the process cartridge; 
         FIG. 5  is a perspective view illustrating a state where a front cover of the image forming apparatus is opened; 
         FIG. 6  is a perspective view illustrating a state where the process cartridge is ejected by opening the front cover of the image forming apparatus; 
         FIG. 7  is a perspective view illustrating a connector according to the first exemplary embodiment of the present invention; 
         FIG. 8  is an exploded perspective view of the connector according to the first exemplary embodiment of the present invention; 
         FIG. 9  illustrates a plug as viewed from six directions; 
         FIG. 10  is a perspective view illustrating a receptacle in an attached state; 
         FIG. 11  illustrates the configuration of a customer replaceable unit memory (CRUM); 
         FIGS. 12A and 12B  are cross-sectional views of the plug; 
         FIG. 13  is a cross-sectional view illustrating the receptacle in an attached state; 
         FIG. 14  is an exploded perspective view of the receptacle; 
         FIG. 15  is a cross-sectional view of the receptacle; 
         FIG. 16  is a perspective view of an attachment portion of the receptacle; and 
         FIG. 17  is a cross-sectional view illustrating a state where the plug and the receptacle of the connector are attached to each other. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present invention will be described below with reference to the drawings. 
     First Exemplary Embodiment 
       FIG. 1  schematically illustrates the overall configuration of an image forming apparatus to which a connector and a process cartridge according to a first exemplary embodiment of the present invention are applied.  FIG. 2  is an enlarged view illustrating a relevant part (such as an image forming device) in the image forming apparatus. 
     Overall Configuration of Image Forming Apparatus 
     An image forming apparatus  1  according to the first exemplary embodiment is, for example, a monochrome printer. The image forming apparatus  1  includes an image forming section  2  as an example of an image forming unit that forms an image onto a recording medium based on image data. 
     The image forming section  2  includes, for example, an image forming device  10  that forms a toner image to be developed by using a toner, which constitutes a developer; a transfer device  20  that transfers the toner image formed by the image forming device  10  onto recording paper  5  as an example of a recording medium; a paper feed device  50  that accommodates therein predetermined recording paper  5  to be fed to a transfer position T of the transfer device  20  and that transports the recording paper  5  thereto; and a fixing device  40  that fixes the toner image, which has been transferred on the recording paper  5  by the transfer device  20 , onto the recording paper  5 . In  FIG. 1 , reference character  1   a  denotes an image forming apparatus body formed of, for example, a support structure member, such as a frame, and an external cover. 
     The image forming device  10  is a single dedicated image forming device for forming a black (K) toner image. The image forming device  10  is disposed at a predetermined position located toward one sidewall (i.e., left sidewall in  FIG. 1 ) in the internal space of the image forming apparatus body  1   a.    
     As shown in  FIG. 1 , the image forming device  10  includes a photoconductor drum  11  as an example of a rotatable image bearing member. The photoconductor drum  11  is surrounded by the following devices. Such devices include a charging device  12  that electrostatically charges an image formable peripheral surface (i.e., image bearing surface) of the photoconductor drum  11  to a predetermined potential; an exposure device  13  as an example of an electrostatic-latent-image forming unit that radiates light onto the electrostatically-charged peripheral surface of the photoconductor drum  11  based on image information (signal) so as to form an electrostatic latent image having a potential difference; a developing device  14  as an example of a developing unit that develops the electrostatic latent image into a toner image by using a black (K) toner contained in a developer; and a drum cleaning device  15  that removes extraneous matter, such as residual toner, from the image bearing surface of the photoconductor drum  11  after the transfer process so as to clean the image bearing surface of the photoconductor drum  11 . 
     The photoconductor drum  11  is obtained by forming the image bearing surface having a photoconductor layer (photosensitive layer) composed of a photosensitive material around the peripheral surface of an electrically-grounded cylindrical or columnar base. The photoconductor drum  11  is supported such that it is rotatable in a direction indicated by an arrow A by receiving a driving force transmitted from a rotational driving device (not shown). 
     The charging device  12  is of a contact type, such as a charging roller disposed in contact with the photoconductor drum  11 . The charging device  12  receives charge voltage from a charge high-voltage power supply device (not shown). With regard to the charge voltage, in a case where the developing device  14  is configured to perform reversal development, a voltage or a current with the same polarity as the charge polarity of the toner supplied from the developing device  14  is supplied to the charging device  12 . The charging device  12  includes a roller-shaped cleaning member  121  that cleans the peripheral surface of the charging roller. 
     The exposure device  13  is configured to radiate light onto the electrostatically-charged peripheral surface of the photoconductor drum  11  in accordance with image information input to the image forming apparatus  1  so as to form an electrostatic latent image on the peripheral surface. When the exposure device  13  is to form an electrostatic latent image, image information (signal) input to the image forming apparatus  1  via an arbitrary unit is transmitted to the exposure device  13 . 
     The exposure device  13  is constituted of a light-emitting-diode (LED) print head that radiates light according to the image information onto the photoconductor drum  11  by using LEDs as multiple light emitting elements arranged in the axial direction of the photoconductor drum  11 , so as form the electrostatic latent image. The exposure device  13  may alternatively be configured to scan laser light according to the image information across the photoconductor drum  11  in the axial direction thereof. 
     As shown in  FIG. 2 , the developing device  14  includes, for example, a developing roller  141 , stirring transport members  142  and  143 , a partition wall  144 , and a roller-shaped layer-thickness regulating member  145 , which are disposed within a housing  140  having an opening and accommodation chambers for a developer  4 . The developing roller  141  retains the developer  4  and transports the developer  4  to a development region that faces the photoconductor drum  11 . The stirring transport members  142  and  143  are, for example, screw augers that transport the developer  4  to make the developer  4  pass the developing roller  141  while stirring the developer  4 . The partition wall  144  separates a first accommodation chamber, which accommodates the stirring transport member  142  therein, from a second accommodation chamber, which accommodates the stirring transport member  143  therein. The layer-thickness regulating member  145  regulates the amount (i.e. layer thickness) of developer retained on the developing roller  141 . A power supply device (not shown) supplies development voltage between the developing roller  141  of the developing device  14  and the photoconductor drum  11 . Each of the developing roller  141  and the stirring transport members  142  and  143  rotates in a predetermined direction by receiving a driving force transmitted from a rotational driving device (not shown). Furthermore, the aforementioned developer  4  used is a two-component developer containing a nonmagnetic toner and a magnetic carrier. In  FIG. 1 , reference character  146  denotes a toner cartridge as an example of a developer container that accommodates therein a developer that at least contains a toner, and reference character  147  denotes a developer supplying device that supplies the developer from the toner cartridge  146  to the developing device  14 . 
     The developing device  14  includes a toner concentration sensor  148  as an example of a toner-concentration detector that detects the toner concentration in the developer  4  accommodated within the housing  140 . The toner concentration sensor  148  is attached to a lower wall surface of the second accommodation chamber, which is where the housing  140  accommodates the stirring transport member  143 . The toner concentration sensor  148  used is, for example, a magnetic permeability sensor. 
     The transfer device  20  is of a contact type equipped with a rotatable transfer roller that comes into contact with the peripheral surface of the photoconductor drum  11  at the transfer position T and that is supplied with transfer voltage. With regard to the transfer voltage, a direct-current voltage with a reversed polarity relative to the charge polarity of the toner is supplied from a power supply device (not shown). 
     As shown in  FIG. 2 , the drum cleaning device  15  includes a cleaning plate  151  that is disposed within a container-shaped body  150  and removes extraneous matter, such as residual toner, and a transport member  152  such as a screw auger (not shown) that transports the extraneous matter collected by the cleaning plate  151  to an external container. The cleaning plate  151  used is a plate-shaped member (such as a blade) composed of, for example, a rubber material. 
     In this exemplary embodiment, the image forming components, such as the photoconductor drum  11  as well as the charging device  12 , the developing device  14 , and the drum cleaning device  15  disposed around the photoconductor drum  11 , are integrally combined so as to constitute a process cartridge  30  as an example of a replaceable unit. As shown in  FIG. 3 , the process cartridge  30  includes a process cartridge body  31  to which the photoconductor drum  11 , the charging device  12 , the developing device  14 , and the drum cleaning device  15  are integrally attached. The process cartridge  30  is attachable to and detachable from the image forming apparatus body  1   a . As shown in  FIG. 4 , a front frame  32  of the process cartridge body  31  is provided with a handle  33  to be manually gripped when attaching or detaching the process cartridge  30  to or from the image forming apparatus body  1   a . Instead of including all of the image forming components, such as the photoconductor drum  11  as well as the charging device  12 , the developing device  14 , and the drum cleaning device  15  disposed around the photoconductor drum  11 , the process cartridge  30  may include some of these image forming components, such as the photoconductor drum  11 , the charging device  12 , and the developing device  14  or the photoconductor drum  11  and the developing device  14 . 
     As shown in  FIG. 5 , the image forming apparatus body  1   a  includes a front cover  60  at the front side thereof (i.e., a side surface facing a user when operating). The front cover  60  is attached to the image forming apparatus body  1   a  in an openable-closable manner via a hinge  61  provided at a lower end of the front cover  60 . 
     The image forming apparatus body  1   a  includes an internal cover  62  that becomes exposed by opening the front cover  60 . The front surface of the internal cover  62  has a substantially rectangular opening  63  used for attaching and detaching the process cartridge  30  and a substantially circular opening  64  used for attaching and detaching the toner cartridge  146 . The process cartridge  30  is attached to or detached from the image forming apparatus body  1   a  by being moved, via the opening  63 , along a guide member, such as a guide rail (not shown), provided within the image forming apparatus body  1   a . By becoming attached to the image forming apparatus body  1   a , the process cartridge  30  receives a driving force and electric power from the image forming apparatus body  1   a . Moreover, by being attached to the image forming apparatus body  1   a , the process cartridge  30  becomes electrically connected to a controller  100  in the image forming apparatus body  1   a  via a connector  70 , which will be described later, so as to become capable of exchanging electric signals (i.e., become communicable) therewith. 
     As shown in  FIG. 1 , the fixing device  40  includes, for example, a heating rotatable member  41  and a pressing rotatable member  42 . The heating rotatable member  41  is of a roller type or a belt type (a roller type in this exemplary embodiment) that is heated by a heater so that the surface temperature of the heating rotatable member  41  is maintained at a preset temperature. The pressing rotatable member  42  is of a roller type or a belt type (a belt type in this exemplary embodiment) that rotates by coming into contact with the heating rotatable member  41  at a predetermined pressure. In the fixing device  40 , a contact area where the heating rotatable member  41  and the pressing rotatable member  42  are in contact with each other serves as a fixing section that performs a predetermined fixing process (i.e., heating and pressing). 
     The paper feed device  50  is disposed at a lower position of the image forming apparatus body  1   a . The paper feed device  50  includes a single (or multiple) paper accommodation member  51  that accommodates therein a stack of recording paper  5  of a desired size and type, and delivering devices  52   a  and  52   b  that deliver the recording paper  5  one-by-one from the paper accommodation member  51 . The paper accommodation member  51  is, for example, attached in a manner such that it is ejectable toward the front side of the image forming apparatus body  1   a.    
     A paper-feed transport path  56  that includes multiple pairs of paper transport rollers  53  and  54  and a transport guide member  55  is provided between the paper feed device  50  and the transfer device  20 . The multiple pairs of paper transport rollers  53  and  54  transport the recording paper  5  delivered from the paper feed device  50  to the transfer position T. In the paper-feed transport path  56 , the pair of paper transport rollers  54  disposed immediately in front of the transfer position T serves as, for example, rollers (registration rollers) that adjust the transport timing of the recording paper  5 . 
     A transport guide member  57  that transports the recording paper  5  having the toner image transferred thereon by the transfer device  20  toward the fixing device  40  is disposed downstream of the transfer device  20 . Moreover, the entrance of the fixing device  40  is provided with an entrance guide member  43  that guides the recording paper  5  toward the fixing section where the heating rotatable member  41  and the pressing rotatable member  42  are in contact with each other. The exit of the fixing device  40  is provided with a transport roller  44  that transports the recording paper  5  that has undergone the fixing process. 
     A paper-output transport path  59  is provided downstream of the fixing device  40 . The paper-output transport path  59  includes a paper output roller  58  for outputting the recording paper  5  having the toner image fixed thereon by the fixing device  40  onto a paper output section  68  disposed at the top of the image forming apparatus body  1   a.    
     In  FIG. 1 , reference character  100  denotes a controller that controls the overall operation of the image forming apparatus  1 . The controller  100  includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and a bus or a communication interface that connects, for example, the CPU and the ROM. 
     Basic Operation of Image Forming Apparatus 
     The basic image forming operation performed by the image forming apparatus  1  will be described below. 
     The following description relates to image forming operation performed when forming a monochrome image constituted of a black toner image by using the image forming device  10 . 
     When the image forming apparatus  1  receives command information requesting image forming operation (printing operation), for example, the image forming device  10 , the transfer device  20  and the fixing device  40  start operating. 
     Then, in the image forming device  10 , the photoconductor drum  11  first rotates in the direction of the arrow A, and the charging device  12  electrostatically charges the surface of the photoconductor drum  11  to a predetermined polarity (negative polarity in this exemplary embodiment) and a predetermined electric potential. Then, the exposure device  13  radiates light onto the electrostatically-charged surface of the photoconductor drum  11  based on an image signal input to the image forming apparatus  1  so as to form an electrostatic latent image having a predetermined potential difference on the surface. 
     Subsequently, the developing device  14  develops the electrostatic latent image formed on the photoconductor drum  11  by supplying a toner, which is electrostatically charged to a predetermined polarity (negative polarity), to the electrostatic latent image and electrostatically adhering the toner thereto. As a result of this developing process, the electrostatic latent image formed on the photoconductor drum  11  becomes a visible toner image developed using the toner. The developing device  14  consumes the toner by making the electrostatic latent image into a visible toner image. The toner concentration within the housing  140  of the developing device  14  is detected by the toner concentration sensor  148  disposed in the second accommodation chamber. A detection signal of the toner concentration sensor  148  is transmitted to the controller  100 . Based on the toner concentration within the developing device  14  detected by the toner concentration sensor  148 , the controller  100  drives a developer supplier  147  at a predetermined timing so as to supply the developer that at least contains the toner from the toner cartridge  146  to the developing device  14 . 
     Subsequently, when the toner image formed on the photoconductor drum  11  of the image forming device  10  is transported to the transfer position T, the transfer device  20  transfers the toner image onto the recording paper  5 . 
     In the image forming device  10  that has completed the transfer process, the drum cleaning device  15  cleans the surface of the photoconductor drum  11  by scraping off extraneous matter, such as residual toner, remaining on the surface of the photoconductor drum  11 . Thus, the image forming device  10  becomes ready for subsequent image forming operation. 
     In the paper feed device  50 , the predetermined recording paper  5  is delivered to the paper-feed transport path  56  in accordance with the image forming operation. In the paper-feed transport path  56 , the pair of paper transport rollers  54  as registration rollers delivers the recording paper  5  to the transfer position T in accordance with the transfer timing. 
     Subsequently, the recording paper  5  having the toner image transferred thereon is transported to the fixing device  40  via the transport guide member  57 . In the fixing device  40 , the recording paper  5  that has undergone the transfer process is introduced to and made to pass through the fixing section between the rotating heating rotatable member  41  and the rotating pressing rotatable member  42  via the entrance guide member  43 , so that a fixing process is performed on the recording paper  5 . Thus, the unfixed toner image becomes fixed onto the recording paper  5 . Finally, the recording paper  5  that has undergone the fixing process is output onto, for example, the paper output section  68 , which is provided at the top of the image forming apparatus  1 , by the paper output roller  58  via the paper-output transport path  59 . 
     As a result of the above operation, the recording paper  5  having a monochrome image formed on one face thereof is output. 
     Every time the image forming operation is executed, the controller  100  accumulatively counts lifespan parameters, such as the number of rotations of the photoconductor drum  11  and the number of printed sheets. When the image forming operation is completed, the controller  100  writes the lifespan parameters, such as the counted number of rotations of the photoconductor drum  11  and the counted number of printed sheets, into a storage unit provided in the toner cartridge  146 , which will be described later. 
     In the image forming apparatus  1 , the layer thickness of the photoconductor layer of the photoconductor drum  11  decreases due to, for example, abrasion while the image forming operation is being continuously performed. Therefore, when the process cartridge  30  including the photoconductor drum  11  reaches its lifespan, such as when the layer thickness of the photoconductor layer of the photoconductor drum  11  decreases to a predetermined value, or when the process cartridge  30  reaches near its lifespan, the controller  100  detects this state based on the lifespan parameters. Then, the controller  100  causes a user interface (not shown) or a display screen of a personal computer connected to the image forming apparatus  1  to display a message prompting the user to replace the process cartridge  30 . The user may then replace the process cartridge  30  as a replaceable unit with a new one. 
     The process cartridge  30  includes a customer replaceable unit memory (CRUM)  712  as an example of a storage unit (integrated circuit) that stores the lifespan parameters, such as the accumulative number of rotations of the photoconductor drum  11  and the accumulative number of printed sheets having images formed thereon by the process cartridge  30 , and that is used for detecting the lifespan of the photoconductor drum  11 . The information stored in the CRUM  712  may be information with which the lifespan of the photoconductor drum  11  is detectable. For example, in addition to or as an alternative to the accumulative number of rotations of the photoconductor drum  11  and the accumulative number of printed sheets, the information may include the accumulative number of pixels in image data, the accumulative operating time of the developing device  14 , and the accumulative amount of toner supplied to the developing device  14 . 
     As shown in  FIG. 6 , in order to replace the process cartridge  30 , the user opens the front cover  60  of the image forming apparatus body  1   a  and pulls the process cartridge  30  toward the front side of the image forming apparatus body  1   a  by using the handle  33  of the process cartridge  30 , thereby taking the used process cartridge  30  out of the image forming apparatus body  1   a.    
     Subsequently, a new process cartridge  30  is pushed through the opening  63  of the image forming apparatus body  1   a  to a predetermined position within the image forming apparatus body  1   a  while being guided by a guide member (not shown), so that the new process cartridge  30  becomes attached to the predetermined position of the image forming apparatus body  1   a.    
     By being attached to the predetermined position of the image forming apparatus body  1   a , the process cartridge  30  becomes capable of receiving a driving force and electric power from the image forming apparatus body  1   a  and also becomes electrically connected to the controller  100  in the image forming apparatus body  1   a.    
     As shown in  FIG. 7 , the image forming apparatus  1  includes a connector  70  used for electrically connecting and disconnecting the process cartridge  30  and the image forming apparatus body  1   a  to and from each other. 
     Configuration of Connector 
       FIG. 7  is a perspective view illustrating the connector  70  according to the first exemplary embodiment of the present invention together with a wire harness.  FIG. 8  is an exploded perspective view of the connector  70 .  FIG. 9  illustrates the connector  70  in an assembled state, as viewed from six directions. 
     As shown in  FIGS. 7 to 9 , the connector  70  includes a male plug  71  as an example of a first connector member to be attached to the process cartridge  30  and a female receptacle  72  as an example of a second connector member to be attached to the image forming apparatus body  1   a . The plug  71  and the receptacle  72  are attachable and detachable to and from each other. As shown in  FIG. 3 , the plug  71  is attached in state where it is secured by being fitted or screwed to the inner surface (located inside the image forming apparatus body  1   a ) of the frame  32  of the process cartridge body  31 . On the other hand, as shown in  FIG. 10 , the receptacle  72  is attached to the image forming apparatus body  1   a  at a position corresponding to the plug  71  of the process cartridge  30 , which is a position where the process cartridge  30  is attached to the image forming apparatus body  1   a , in a so-called floating state such that the receptacle  72  allows the process cartridge  30  to move relative to the image forming apparatus body  1   a  in two directions intersecting the attaching-detaching direction, namely, the vertical direction and the horizontal direction, so as to compensate for an error (i.e., positional displacement) in the attached position of the process cartridge  30 . In  FIG. 10 , reference character  34  denotes a stopper member that is provided at the process cartridge  30  and is used for positioning the plug  71  by being brought into abutment with an internal frame  65  of the image forming apparatus body  1   a.    
     The plug  71  includes a substantially-rectangular-parallelepiped plug housing  710  composed of an insulation material, such as synthetic resin. As shown in  FIG. 7 , the plug housing  710  has a vertically-long rectangular shape whose width is smaller than the height thereof when viewed from the front side of the image forming apparatus  1 . Furthermore, the front end surface of the plug housing  710  is provided with a vertically-long rectangular opening  711  having a small width. The opening  711  is provided for attaching and detaching the CRUM  712 , which is an integrated-circuit (IC) memory as an example of an integrated circuit having multiple first electrodes, to and from the plug housing  710 . The integrated circuit includes not only the integrated circuit itself but also an integrated circuit mounted on a circuit substrate. The multiple electrodes included in the integrated circuit includes not only multiple electrodes (terminals) provided in the integrated circuit itself but also multiple electrodes that are provided in the substrate on which the integrated circuit is mounted and that are respectively connected to the multiple electrodes of the integrated circuit. As shown in  FIG. 11 , the CRUM  712  includes an IC substrate  713  formed of a printed substrate having a substantially rectangular shape in plan view. An electrically erasable programmable read-only memory (EEP-ROM)  714 , which is a nonvolatile memory as an example of an integrated circuit, is mounted on a first surface of the IC substrate  713 . A second surface of the IC substrate  713  is provided with multiple (four in  FIG. 11 ) first electrodes  715   1  to  715   4  that are connected to the terminals of the EEP-ROM  714  and are exposed to the outside such that they are externally contactable. The four first electrodes  715   1  to  715   4  are respectively connected to a GND terminal, a CLK terminal, a VCC terminal, and a DATA terminal of the EEP-ROM  714 . Although four first electrodes  715   1  to  715   4  are provided relative to the EEP-ROM  714  in the exemplary embodiment shown in  FIG. 11 , the number of first electrodes  715   1  to  715   4  is not limited to four and may be three or fewer or five or more. The number of electrode terminals of the EEP-ROM  714  and the number of first electrodes  715  do not have to be equal to each other, and the number of first electrodes  715  may be smaller than the number of electrode terminals of the EEP-ROM  714 . In  FIG. 11 , reference characters  713   a  and  713   b  denote holes to be used when, for example, removing the CRUM  712  from the plug housing  710 . 
     Accordingly, the CRUM  712  is a module that includes the EEP-ROM  714 , which is a replaceable nonvolatile memory. The four first electrodes  715   1  to  715   4  of the IC substrate  713  each have an elongate rectangular shape in the inserting direction and are arranged parallel to one another with a predetermined distance therebetween in the direction intersecting the inserting direction. Of the four first electrodes  715   1  to  715   4 , a GND electrode  715   1  disposed at one end protrudes toward the leading edge in the inserting direction and is given a length that is larger than those of the remaining electrodes  715   2  to  715   4 . Therefore, when the CRUM  712  is inserted into the plug  71 , the GND electrode  715   1  is first connected to one of contacts  723  of the receptacle  72 , which will be described later, by being brought into contact therewith, and the remaining electrodes  715   2  to  715   4  are subsequently connected to the remaining contacts  723  of the receptacle  72  by being brought into contact therewith. 
     As shown in  FIG. 8 , the plug housing  710  includes a retainer  716  at one side surface thereof in a direction X intersecting an attaching-detaching direction Z. For example, by press-fitting the CRUM  712  with a small force, the retainer  716  retains the CRUM  712  in a secured state. The retainer  716  spatially communicates with the opening  711  provided in the end surface of the plug housing  710  and used for attaching and detaching the CRUM  712 . The retainer  716  has a planar shape substantially similar to that of the IC substrate  713  of the CRUM  712 . Opposite ends of the retainer  716  in a width direction Y intersecting the attaching-detaching direction Z of the CRUM  712  are respectively provided with a guide groove  716   a  and a guide wall  716   b . The guide groove  716   a  guides a first edge of the CRUM  712  while covering front and rear surfaces thereof. The guide wall  716   b  guides a second edge of the CRUM  712  while being in contact therewith. Moreover, the leading end of the retainer  716  in the attaching-detaching direction Z is provided with a stopper wall  716   c  with which the leading edge of the CRUM  712  is brought into abutment so as to position the CRUM  712  in a retained state. Furthermore, the retainer  716  includes a recess  716   d  that is depressed inward from the one side surface of the plug housing  710  so as to accommodate the EEP-ROM  714  mounted on one surface of the CRUM  712 . As shown in  FIGS. 7 and 8 , opposite ends of the recess  716   d  in the width direction Y intersecting the attaching-detaching direction Z are respectively provided with protrusions  717  that extend in the attaching-detaching direction Z and that guide the CRUM  712  by coming into contact with one surface of the CRUM  712 . The CRUM  712  is retained with an appropriate retaining force by appropriately setting, for example, the width of the guide groove  716   a  of the retainer  716  and the spacing between the guide groove  716   a  and the guide wall  716   b  so that, in a state where the CRUM  712  is inserted in the plug housing  710 , the CRUM  712  does not accidentally move even when an external force is applied to the process cartridge  30  during an attaching or detaching process thereof. 
     As shown in  FIGS. 12A and 12B , a side surface of the plug housing  710  opposite the side thereof to which the CRUM  712  is inserted is provided with a second retainer  719  that securely retains multiple (three in  FIGS. 12A and 12B ) contacts  718  as an example of second electrodes to be connected to a wire harness  148   a  of the toner concentration sensor  148 . The second retainer  719  is constituted of multiple (three in  FIGS. 12A and 12B ) grooves  719   a  that are provided in the attaching-detaching direction of the plug housing  710  at one end of the plug housing  710  in the direction intersecting the attaching-detaching direction. The base ends of the grooves  719   a  spatially communicate with an insertion hole  719   b  provided at the base end of the plug housing  710 . 
     As mentioned above, the contacts  718 , to which signal wires  148   b  of the wire harness  148   a  of the toner concentration sensor  148  are to be contact-bonded, are securely retained in the grooves  719   a  by, for example, press-fitting the contacts  718  therein. As shown in the lower part of  FIG. 8 , the contacts  718  are each formed into a hollow or solid rod shape, such as a prismatic shape or a columnar shape, with a pointy end  718   a  by bending or shaping a plate-shaped or rod-shaped electrically conductive material, such as a thin metal plate, by pressing where appropriate. A base end  718   b  of each contact  718  (i.e., the end to be connected to the wire harness  148   a  of the toner concentration sensor  148 ) is folded into a substantially U-shape in cross section so as to enhance rigidity and also to ensure the connection with the wire harness  148   a . The base ends  718   b  of the contacts  718  are connected to the signal wires  148   b  of the wire harness  148   a  by, for example, contact bonding. 
     The contacts  718  are inserted through the insertion hole  719   b  and are securely retained in the grooves  719   a  so as to be fixed to predetermined positions in the plug housing  710 . Moreover, each contact  718  is attached such that a portion thereof (i.e., the lower surface thereof in  FIG. 12A ) is exposed, thus making the contact  718  contactable from the outside. 
     As shown in  FIG. 8 , opposite outer side surfaces of the plug housing  710  in the direction Y intersecting the inserting direction Z of the CRUM  712  are respectively provided with grooves  719   c  for positioning the plug  71  relative to the receptacle  72  in the direction X intersecting the inserting direction Z when attaching the plug  71  to the receptacle  72 . 
     The receptacle  72  to be attached to the image forming apparatus body  1   a  includes a substantially-rectangular-parallelepiped receptacle housing  720  that is slightly larger than the plug  71  composed of an insulation material, such as synthetic resin. As shown in  FIG. 7 , the front end surface of the receptacle housing  720  is provided with a vertically-long-rectangular opening  721  used for attaching and detaching the plug  71 . Furthermore, as shown in  FIG. 13 , in order to accommodate the plug  71  while being in spatial communication with the opening  721 , the receptacle housing  720  is provided with a recess  722  therein, which has a shape corresponding to the outer peripheral shape of the plug  71 . 
     Furthermore, as shown in  FIG. 14 , the receptacle housing  720  includes a total of seven receptacle contacts  723 , four on one side and three on the other side. The receptacle contacts  723  are provided as connection units that are directly connected to the multiple first electrodes  715   1  to  715   4  of the CRUM  712  and the multiple contacts  718   1  to  718   3  when the plug  71  is attached. The seven receptacle contacts  723  have identical configurations. 
     As shown in an enlarged view in  FIG. 14 , each receptacle contact  723  is formed into a substantially H-shape in front view by bending, connecting, or shaping a plate-shaped or rod-shaped electrically conductive material, such as a thin metal plate, by pressing where appropriate. The receptacle contact  723  has an intermediate portion  723   a  that forms an elongate rectangular flat plate. One long edge of the intermediate portion  723   a  forming an elongate rectangular flat plate is provided with locking segments  723   b  that protrude away from each other in the longitudinal direction of the intermediate portion  723   a  and that are to be securely fitted in the receptacle housing  720 . The other long edge of the intermediate portion  723   a  is provided with a first connection segment  723   c  and a second connection segment  723   d  that protrude away from each other. The first connection segment  723   c  is to be connected to a signal wire of a wire harness  101 , which is for connecting to the controller  100 , by, for example, pressure contact. The second connection segment  723   d  is to be electrically connected to one of the multiple electrodes  715   1  to  715   4  of the CRUM  712  and one of the contacts  718   1  to  718   3  in the plug  71  by being brought into contact therewith. More specifically, the first connection segment  723   c  protrudes outward from the receptacle housing  720 , whereas the second connection segment  723   d  protrudes inward to the receptacle housing  720 . A side surface of the second connection segment  723   d  located toward the distal end thereof (i.e., a surface facing inwardly toward the recess  722 ) is provided with a small substantially-triangular protrusion  723   d ′ that comes into contact with one of the multiple electrodes  715   1  to  715   4  of the CRUM  712  and one of the contacts  718   1  to  718   3  in the plug  71 . The second connection segment  723   d  is formed to be longer than the first connection segment  723   c.    
     As shown in  FIG. 14 , the receptacle contacts  723  are fitted in a state where they are inserted into first and second recesses  724  and  725  provided in the base end surface of the receptacle housing  720  (i.e., the end surface thereof to be attached to the image forming apparatus body  1   a ). In this case, as shown in  FIG. 15 , the second connection segments  723   d  of the receptacle contacts  723  are securely positioned such that the protrusions  723   d ′ thereof protrude to predetermined positions in the recess  722  in the receptacle housing  720 . As a result, the protrusions  723   d ′ of the second connection segments  723   d  of the receptacle contacts  723  are respectively positioned at positions corresponding to the four first electrodes  715   1  to  715   4  of the CRUM  712  of the plug  71  and the three contacts  718  ( 718   1  to  718   3 ). 
     As shown in  FIG. 14 , the first and second recesses  724  and  725  of the receptacle housing  720  are provided with grooves  724   a  and  725   a  that are spaced apart by a predetermined distance for guiding and securely positioning the receptacle contacts  723 . Moreover, as shown in  FIG. 8 , a four-pole pressure-contact socket  726  composed of synthetic resin or synthetic rubber for connecting four signal wires  101   a  of the wire harness  101 , which is for connecting to the controller  100 , to the first connection segments  723   c  of the receptacle contacts  723  by pressure contact are fitted to the first recess  724  of the receptacle housing  720  by, for example, press-fitting. The ends of the four signal wires  101   a  of the wire harness  101  have terminals  101   b  connected thereto by, for example, contact bonding. The terminals  101   b  connected to the signal wires  101   a  are secured in a state where they are inserted to predetermined positions of the pressure-contact socket  726 , so that the terminals  101   b  and the first connection segments  723   c  of the receptacle contacts  723  are connected to each other by pressure contact inside the pressure-contact socket  726 . 
     Furthermore, a three-pole pressure-contact socket  727  composed of synthetic resin or synthetic rubber for connecting three signal wires  101   c  of the wire harness  101 , which is for connecting to the controller  100 , to the first connection segments  723   c  of the receptacle contacts  723  by contact bonding is press-fitted to the second recess  725  of the receptacle housing  720 . The three signal wires  101   c  of the wire harness  101  have terminals (not shown) similar to the terminals  101   b  connected to the ends thereof by, for example, contact bonding. Moreover, the terminals connected to the respective signal wires  101   c  are secured in a state where they are inserted in the pressure-contact socket  727 , and the terminals and the first connection segments  723   c  of the receptacle contacts  723  are connected to each other by pressure contact inside the pressure-contact socket  727 . 
     As shown in  FIG. 13 , the receptacle housing  720  includes an attachment portion  728  to be attached to the image forming apparatus body  1   a . The attachment portion  728  is constituted of snap joining portions provided at opposite side surfaces of the receptacle housing  720 . The attachment portion  728  includes side plates  728   a  that are provided at opposite sides of the opening  721  in the receptacle housing  720  and that slightly protrude outward, and flexible plates  728   b  that extend substantially parallel to the opposite side surfaces of the receptacle housing  720  from the outer edges of the side plates  728   a  and that are relatively thin so as to be bendable. The end of each flexible plate  728   b  is provided with an engagement projection  728   c  that is substantially triangular in cross section and that protrudes laterally from the surface of the flexible plate  728   b . The ends of the two engagement projections  728   c  are separated from each other by a distance that is smaller than the opening width of an opening  66  in the internal frame  65 , which will be described below. 
     Furthermore, the base end of the receptacle housing  720  is provided with positioning portions  729  used for positioning the receptacle housing  720  in the attaching-detaching direction by being brought into contact with the internal cover  62  of the image forming apparatus body  1   a . The positioning portions  729  are provided at four locations corresponding to the four corners at the base end of the receptacle housing  720 . 
     As shown in  FIG. 16 , the internal frame  65  of the image forming apparatus body  1   a  is provided with the opening  66  having a substantially rectangular shape that is slightly larger than the outer shape of the receptacle housing  720  so that the receptacle housing  720  of the receptacle  72  is insertable through the opening  66 . The opening width of the opening  66  is larger than the width of the receptacle housing  720 , and the opening height of the opening  66  is larger than the height of the receptacle housing  720  (i.e., the distance between the left and right flexible plates  728   b  to be described later). In  FIG. 16 , reference character  67  denotes an opening provided in the internal frame  65  for attaching and detaching the process cartridge  30 . 
     As shown in  FIG. 13 , with regard to the receptacle  72 , the receptacle housing  720  is inserted through the opening  66  formed in the internal frame  65  of the image forming apparatus body  1   a  and is pushed until the positioning portions  729  of the receptacle housing  720  come into contact with the surface of the internal frame  65  of the image forming apparatus body  1   a , so that the inclined surfaces of the substantially-triangular engagement projections  728   c  included in the attachment portion  728  constituted of the snap joining portions come into contact with the inner peripheral edge of the opening  66  of the internal frame  65 , thereby causing the left and right flexible plates  728   b  to elastically bend inward. When the base ends of the engagement projections  728   c  have passed through the opening  66 , the left and right flexible plates  728   b  restore their original shape. Accordingly, in a state where the internal frame  65  is securely clamped by the positioning portions  729  and the engagement projections  728   c , the receptacle housing  720  is securely attached to a predetermined position of the image forming apparatus body  1   a . In this case, since there is a gap between the opening  66  of the image forming apparatus body  1   a  and the receptacle housing  720 , the receptacle housing  720  is allowed to move within the range of the gap in the direction intersecting the attaching direction of the receptacle  72 . 
     Operation of Characteristic Section of Image Forming Apparatus 
     In the image forming apparatus  1  to which the connector  70  according to this exemplary embodiment is applied, the process cartridge  30  is replaced in the following manner. 
     As shown in  FIG. 7 , with regard to the process cartridge  30 , the controller  100  is capable of reading and writing information related to, for example, the lifespan of the photoconductor drum  11  stored in the CRUM  712  via the connector  70 , and the controller  100  is capable of receiving a detection signal from the toner concentration sensor  148  via the wire harness  148   a . When the controller  100  determines that a predetermined replacement condition is satisfied, such as when the controller  100  determines that the layer thickness of the photoconductor layer of the photoconductor drum  11  has decreased to a predetermined value, based on the information related to, for example, the lifespan of the photoconductor drum  11  stored in the CRUM  712 , the controller  100  causes, for example, the user interface or the display screen of the personal computer connected to the image forming apparatus  1  to display a message prompting a user to replace the process cartridge  30  with a new one. As shown in  FIG. 5 , when replacing the process cartridge  30 , the process cartridge  30  is pulled toward the front side of the image forming apparatus body  1   a  in a state where the front cover  60  of the image forming apparatus  1  is opened, and the used process cartridge  30  is removed from the image forming apparatus body  1   a.    
     In this case, as shown in  FIG. 3 , the plug  71  provided at the process cartridge body  31  moves toward the front side of the image forming apparatus body  1   a  as the process cartridge  30  moves, and the plug  71  is removed from the receptacle  72  provided at the image forming apparatus body  1   a.    
     Subsequently, a new process cartridge  30  is inserted to a predetermined position inside the image forming apparatus body  1   a  through the opening  63  provided in the front surface of the image forming apparatus body  1   a . As a result of this inserting process of the process cartridge  30 , the plug  71  of the connector  70  provided at the process cartridge  30  becomes attached to the receptacle  72  provided at the image forming apparatus body  1   a . Then, the front cover  60  of the image forming apparatus  1  is closed. 
     As shown in  FIG. 17 , when the plug  71  of the connector  70  is attached to the receptacle  72 , the four electrodes  715   1  to  715   4  of the CRUM  712  exposed at one side surface of the plug  71  and the four contacts  723  disposed at one side surface inside the receptacle  72  come into contact or pressure contact with each other, and the three contacts  718   1  to  718   3  connected to the wire harness  148   a  of the toner concentration sensor  148  exposed at the other side surface of the plug  71  and the three contacts  723  disposed at the other side surface inside the receptacle  72  come into contact or pressure contact with each other, whereby an electrical connection is established. As a result, the toner concentration sensor  148  and the CRUM  712  of the process cartridge  30  become capable of exchanging signals (i.e., become communicable) with the controller  100  in the image forming apparatus body  1   a.    
     More specifically, as shown in  FIG. 17 , when the plug  71  is attached to the receptacle  72 , the protrusions  723   d ′ of the second connection segments  723   d  of the receptacle contacts  723 , which are disposed at one side, come into contact with the four first electrodes  715   1  to  715   4  of the CRUM  712 , and the protrusions  723   d ′ of the receptacle contacts  723 , which are disposed at the other side, come into contact with the three contacts  718  connected to the toner concentration sensor  148 , so as to become respectively connected to the CRUM  712  in the plug  71  and the toner concentration sensor  148 . 
     The contact pressure of the receptacle contacts  723  relative to the four first electrodes  715   1  to  715   4  and the three contacts  718   1  to  718   3  is appropriately set in accordance with, for example, the arrangement and the shape of the receptacle contacts  723  relative to the receptacle housing  720 . 
     Accordingly, in the connector  70  according to the above exemplary embodiment, the plug  71  provided at the process cartridge  30  is not provided with a connection unit, such as connection terminals, for electrically connecting to the CRUM  712  fitted in the plug  71  and the wire harness  148   a  extending from the toner concentration sensor  148 , so that the configuration of the plug  71  may be simplified. Moreover, since the plug  71  provided at the process cartridge  30  is not provided with a connection unit, the plug  71  may be reduced in size and the component cost may be reduced. In addition, the process cartridge  30  to which the plug  71  is attached may also be reduced in size, and the image forming apparatus  1  may also be reduced in size. 
     Although the exemplary embodiment described above is applied to a monochrome image printing apparatus as an image forming apparatus, the exemplary embodiment may alternatively be applied to a full-color image forming apparatus equipped with an image forming device corresponding to yellow (Y), magenta (M), cyan (C), and black (K) colors. 
     Furthermore, although the exemplary embodiment described above relates to a connector equipped with a plug and a receptacle, the connector may alternatively be constituted of a combination of, for example, a male plug and a female plug. 
     Furthermore, although the exemplary embodiment described above relates to a case where a connector is applied to an image forming apparatus, the connector may alternatively be applied to an apparatus, such as an image reading apparatus, other than the image forming apparatus. 
     The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.