Abstract:
A developer cartridge according to one aspect of the invention is attachable to a photoconductor unit that comprises a photoconductive drum. The developer cartridge may comprise a developing frame defining a developer container configured to contain developer, the developing frame having a first side and a second side; a developing roller located at the first side of the developing frame so as to receive developer conveyed from the developer container in a first direction; a contact terminal located at the second side of the developing frame; and a memory electrically connected to the contact terminal, wherein the first side is downstream in the first direction from the second side.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. Ser. No. 13/182,141, filed Jul. 13, 2011, which was a divisional of U.S. Ser. No. 12/034,203, filed Feb. 20, 2008 which is based upon and claims the benefit of priority from Japanese Patent Application No. 2007-040029, filed on Feb. 20, 2007, and Japanese Patent Application No. 2007-122706, filed on May 7, 2007, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an image forming device, a process cartridge, and a developer cartridge. 
     BACKGROUND 
     In general, in image forming devices such as laser printers and digital copiers, a laser beam is applied to a photoconductive member to correspond to data of an image to be printed, thereby forming an electrostatic latent image on the photoconductive member. 
     In order to facilitate maintenance of the devices and reduce the maintenance cost, both or one of a photoconductive drum and a developing roller can be embodied as a replaceable cartridge to the image forming device. For example, a developer cartridge having a developing roller is attached to the image forming device, or a developer cartridge is attached to a photoconductor cartridge having a photoconductive drum to form a process cartridge and then the process cartridge is attached to the image forming device. 
     At the time of forming an image by supplying a toner to an electrostatic latent image, it is necessary that the developing roller comes in uniform and precise contact with the photoconductive drum in the axis direction. However, in the structure that the photoconductor cartridge, the developer cartridge, or the process cartridge can be replaced, the distribution of the contact force in the axis direction may not be uniform. Therefore, there is provided that a developing-roller pressing mechanism for pressing the developing roller to the photoconductive member precisely and uniformly in the axis direction even after replacing the cartridges is disposed at one position or plural positions of the image forming device or the cartridges. Such a mechanism is disclosed, for example, JP-A-2000-250378. 
     The process cartridge or the developer cartridge thereof may include a memory unit that stores information such as an amount of toner and characteristics of members useful for easily and punctually performing the replacement or maintenance of the cartridges. Such a memory unit is disclosed, for example, JP-A-8-211818. In response to a request for performance or a decrease in cost, a contact IC chip may be employed as the memory unit. In this way, when the memory unit electrically connected to the main body is provided, it is necessary to make a stable contact between a terminal of the memory unit and a terminal of the image forming device to allow the memory unit to normally work. 
     However, when an electrical contact of the memory unit is disposed independent of the developing-roller pressing mechanism of JP-A-2000-250378, the pressing force of the developing roller may not be balanced and thus the developing roller may not be pressed to the photoconductive member uniformly in the axis direction. 
     SUMMARY 
     One aspect of the invention has an object to provide an image forming device, a process cartridge, and a developer cartridge, which can electrically connect a memory unit to a main body while keeping a pressing force of a developing roller to a photoconductive drum uniform in the axis direction. 
     According to a first aspect of the invention, there is provided an image forming device comprising: a main body; a photoconductive drum; a developer cartridge comprising: a developing roller pressed to the photoconductive drum and extending in an axis direction; and a developing frame supporting the developing roller, wherein the developer cartridge comprises: a memory unit attached to the developing frame; and a first terminal exposed externally on the developing frame and electrically connected to the memory unit, and wherein the main body comprises: an electric circuit; pressing members respectively disposed at a plurality of positions with respect to the axis direction and configured to abut the developing frame to press the developing roller to the photoconductive drum uniformly in the axis direction; and a second terminal electrically connected to the electric circuit and disposed at at least one of the pressing members to contact with the first terminal. 
     According to a second aspect of the invention, there is provided a process cartridge comprising: a photoconductor cartridge comprising a photoconductive drum supported by a photoconductor frame; and a developer cartridge detachably attached to the photoconductor cartridge and comprising a developing roller extending in an axis direction, wherein the developer cartridge comprises: a developing frame that supports the developing roller; a memory unit attached to the developing frame; and a first terminal exposed on an outer portion of the developing frame and electrically connected to the memory unit, and wherein the photoconductor cartridge comprises: pressing members respectively disposed at a plurality of positions with respect to the axis direction and configured to press the developing roller to the photoconductive drum uniformly in the axis direction; a second terminal disposed at at least one of the pressing members to contact with the first terminal and presses the developer cartridge toward the photoconductive drum; and a third terminal electrically connected to the second terminal and disposed at an outer portion of the photoconductor frame to allow an electric contact with an external electrical contact. 
     According to a third aspect of the invention, there is provided a process cartridge comprising: a photoconductor cartridge comprising a photoconductive drum supported by a photoconductor frame; and a developer cartridge detachably attached to the photoconductor cartridge and comprising a developing roller extending in an axis direction, wherein the developer cartridge comprises: a developing frame; a memory unit attached to the developing frame; pressing members respectively disposed at a plurality of positions with respect to the axis direction to press the developing roller to the photoconductive drum uniformly in the axis direction; and a first terminal electrically connected to the memory unit and disposed at at least one of the pressing members, and wherein the photoconductor cartridge comprises: second terminals respectively disposed at a plurality of positions in the axis direction to press the developer cartridge to the photoconductive drum, at least one of the second terminals being abutted on by the first terminal; and a third terminal electrically connected to the second terminal and disposed at an outer portion of the photoconductor frame to allow an electric contact with an external electrical contact. 
     According to a fourth aspect of the invention, there is provided a developer cartridge attachable to a photoconductor unit that comprises a photoconductive drum, said developer cartridge comprising: a developing frame; a developing roller rotatably supported by the developing frame, and pressed to the photoconductive drum in a pressing direction when the developer cartridge is attached to the photoconductor cartridge; a memory unit attached to the developing frame; and a terminal electrically connected to the memory unit and disposed at an outer portion of the developing frame at a position substantially opposite to the developing roller with respect to the pressing direction. 
     According to a fifth aspect of the invention, there is provided a developer cartridge attachable to a photoconductive unit, the photoconductor unit comprises: a photoconductive drum supported by a photoconductor frame; pressing members; a second terminal disposed at at least one of the pressing members; and a third terminal electrically connected to the second terminal and disposed at an outer portion of the photoconductor frame to allow an electric contact with an external electrical contact, said developer cartridge comprising: a developing roller extending in an axis direction; a developing frame that supports the developing roller; a memory unit attached to the developing frame; and a first terminal exposed on an outer portion of the developing frame and electrically connected to the memory unit, wherein, when the developer cartridge is attached to the photoconductor unit, the developing frame receives a force from the pressing members of the photoconductor unit to press the developing roller to the photoconductive drum uniformly in the axis direction, and wherein the first terminal is disposed at a position to contact with the second terminal when the developer cartridge is attached to the photoconductor unit. 
     According to a sixth aspect of the invention, there is provided a developer cartridge attachable to a photoconductive unit, the photoconductor unit comprises: a photoconductive drum supported by a photoconductor frame; a second terminal; and a third terminal electrically connected to the second terminals and disposed at an outer portion of the photoconductor frame to allow an electric contact with an external electrical contact, said developer cartridge comprising: a developing roller extending in an axis direction; a developing frame that supports the developing roller; a memory unit attached to the developing frame; pressing members respectively disposed at the developing frame at a plurality of positions with respect to the axis direction; and a first terminal disposed at at least one of the pressing members electrically connected to the memory unit, wherein, when the developer cartridge is attached to the photoconductor unit, the pressing members urges the second terminals so that the second terminals apply a force to press the developing roller to the photoconductive drum uniformly in the axis direction, and wherein, when the developer cartridge is attached to the photoconductor unit, the first terminal contacts with the second terminal 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cross-sectional view illustrating an image forming device according to a first embodiment of the invention; 
         FIG. 2  is a perspective view illustrating a photoconductor cartridge and a developer cartridge as viewed from the front side; 
         FIG. 3  is a side cross-sectional view illustrating a front portion of a process cartridge and a rear portion of a front cover in a state where the process cartridge is attached to a main casing and the front cover is closed; 
         FIG. 4  is a cross-sectional view taken along Line IV-IV of  FIG. 3 , which shows a state where a developing-frame terminal is connected to a main-body terminal; 
         FIG. 5  is a side cross-sectional view illustrating the front portion of the process cartridge and the rear portion of the front cover in a state where the process cartridge is attached to the main casing and the front cover is closed according to a second embodiment; 
         FIG. 6  is a perspective view illustrating a positional relation between the front cover and the process cartridge according to a third embodiment; and 
         FIG. 7  is a side cross-sectional view illustrating the front portion of the process cartridge and the rear portion of the front cover in a state where the process cartridge is attached to the main casing and the front cover is closed. 
     
    
    
     DESCRIPTION 
     (First Embodiment) 
     &lt;Entire Configuration of Image Forming Device&gt; 
     Hereinafter, an embodiment of the invention will be described in detail with reference to the attached drawings. In the drawings,  FIG. 1  is a side cross-sectional view illustrating an image forming device and  FIG. 2  is a perspective view illustrating a photoconductor cartridge and a developer cartridge. In the following description, the right side in  FIG. 1  is defined as a front and the left side is defined as a rear. Also, regarding directions of a process cartridge  30 , a photoconductor cartridge  31 , and a developer cartridge  33  (which will be described later), the following description refers to directions in a state where they are attached to an image forming device (see  FIG. 1 ). 
     As shown in  FIG. 1 , an image forming device  1  includes a feeder unit  4  that feeds a sheet  3  into a main casing  2  (main body) and an image forming unit  5  that forms an image on the fed sheet  3 . 
     A front cover  11  (opening and closing member) that can be freely opened and closed is disposed at a front portion of the main casing  2 . A process cartridge  30  to be described later is detachably attached through an opening formed when the front cover  11  is opened. 
     &lt;Configuration of Feeder Unit&gt; 
     The feeder unit  4  includes a sheet feeding tray  12  that is detachably attached to the bottom of the main casing  2  and a sheet pressing plate  13  disposed in the sheet feeding tray  12 . The feeder unit  4  further includes a feed roller  14  disposed above an end of the sheet feeding tray  12 , a feed pad  15 , and sheet-powder removing rollers  16  and  17  disposed more downstream in a direction in which the sheet  3  is conveyed than the feed roller  14 . The feeder unit  4  includes a registration roller  18  disposed more downstream than the sheet-powder removing rollers  16  and  17 . 
     In the feeder unit  4  having the above-mentioned configuration, the sheet  3  in the sheet feeding tray  12  is made to move to the feed roller  14  by the sheet pressing plate  13 . The sheet  3  is sent from the feed roller  14  and the feed pad  15 , and then passes through the sheet-powder removing rollers  16 ,  17  and the registration roller  18 . Accordingly, the sheet  3  is conveyed to the image forming unit  5  sheet by sheet. 
     &lt;Configuration of Image Forming Unit&gt; 
     The image forming unit  5  includes a scanner unit  20 , a process cartridge  30 , and a fixing unit  40 . 
     &lt;Configuration of Scanner Unit&gt; 
     The scanner unit  20  is disposed in an upper portion in the main casing  2  and includes a laser emitting portion (not shown), a polygon mirror  21  that is rotationally driven, lenses  22  and  23 , and reflecting mirrors  24 ,  25 , and  26 . As indicated by a dotted line, a laser beam based on image data and emitted from the laser emitting portion is subjected to reflection or transmission in the order of the polygon mirror  21 , the lens  22 , the reflecting mirrors  24  and  25 , the lens  23 , and the reflecting mirror  26  and is applied to the surface of a photoconductive drum  32  of the process cartridge  30  at a high speed. 
     &lt;Configuration of Process Cartridge&gt; 
     The process cartridge  30  is disposed below the scanner unit  20  and is detachably attached to the main casing  2 . The process cartridge  30  includes a photoconductor cartridge  31  and a developer cartridge  33  as an example of the cartridge. 
     &lt;Configuration of Developer Cartridge&gt; 
     The developer cartridge  33  is detachably attached to a hollow photoconductor frame  31 A constituting the outer frame of the photoconductor cartridge  31  (see  FIG. 2 ) and includes a developing roller  36 , a thickness regulating blade  37 , a supply roller  38 , and a toner hopper  39  as an example of the developer container. The developing roller  36  is rotatably supported by a hollow developing frame  33 A (cartridge frame) constituting the outer frame of the developer cartridge  33 . 
     A toner (not shown) as an example of the developer contained in the toner hopper  39  is supplied to the developing roller  36  with the rotation in the arrow direction (in the counterclockwise direction) of the supply roller  38 . At this time, the toner is frictionally charged positive between the supply roller  38  and the developing roller  36 . The toner supplied to the developing roller  36  enters between the thickness regulating blade  37  and the developing roller  36  with the rotation in the arrow direction (in the counterclockwise direction) of the developing roller  36  and is held as a thin layer having a constant thickness on the developing roller  36 . 
     &lt;Configuration of Photoconductor Cartridge&gt; 
     The photoconductor cartridge  31  includes a photoconductive drum  32 , a scorotron charging unit  34 , and a transfer roller  35 . The photoconductive drum  32  is supported by the photoconductor frame  31 A so as to be rotatable in the arrow direction (in the clockwise direction). The drum body of the photoconductive drum  32  is grounded and the surface thereof is formed of a positively-charging photoconductive layer made of polycarbonate. 
     The scorotron charging unit  34  is disposed above the photoconductive drum  32  with a predetermined gap therebetween so as not to contact with the photoconductive drum  32 . The scorotron charting unit  34  is a positively-charging scorotron charger that generates a corona discharged from a charging wire made of tungsten or the like and uniformly charges the surface of the photoconductive drum  32  in a positive polarity. 
     The transfer roller  35  is disposed below the photoconductive drum  32  so as to contact with the photoconductive drum  32  and is supported by the photoconductor frame  31 A so as to be rotatable in the arrow direction (in the counterclockwise direction). In the transfer roller  35 , a metal roller shaft is coated with a conductive rubber material. A transfer bias is applied to the transfer roller  35  by static current control at the time of transfer. 
     In the photoconductor cartridge  31  having the above-mentioned configuration, the surface of the photoconductive drum  32  is positively charged by the scorotron charging unit  34  and then is exposed by means of high-speed scanning of a laser beam from the scanner unit  20 . Accordingly, the potential of the exposed portion is lowered to form an electrostatic latent image based on image data. 
     Here, the “electrostatic latent image” means the exposed portion of which the potential is lowered by means of the exposure to the laser beam, on the surface of the photoconductive drum  32  uniformly charged in a positive polarity. 
     Next, when the toner held on the developing roller  36  comes in contact with the photoconductive drum  32  with the rotation of the developing roller  36 , the toner is supplied to the electrostatic latent image formed on the surface of the photoconductive drum  32 . In this way, the toner is selectively held on the surface of the photoconductive drum  32  and is thus visualized, thereby forming a toner image by means of a reversal development. 
     Thereafter, the photoconductive drum  32  and the transfer roller  35  are rotationally driven to convey the sheet  3 . By conveying the sheet  3  between the photoconductive drum  32  and the transfer roller  35 , a toner image held on the surface of the photoconductive drum  32  is transferred to the sheet  3 . 
     &lt;Configuration of Fixing Unit&gt; 
     The fixing unit  40  is disposed on the downstream side of the process cartridge  30  and includes a heating roller  41 , a pressing roller  42  that is disposed to be opposite the heating roller  41  so as to press the heating roller  41 , and a pair of conveying roller  43  disposed more downstream than the heating roller  41  and the pressing roller  42 . 
     In the fixing unit  40  having the above-mentioned configuration, the toner transferred to the sheet  3  is thermally fixed while the sheet  3  passes between the heating roller  41  and the pressing roller  42  and thereafter, the sheet  3  is conveyed to a sheet discharging path  44  by the conveying rollers  43  and a flapper  49 . The sheet  3  sent to the sheet discharging path  44  is discharged to a sheet discharging tray  46  by the discharge roller  45 . A part of the rear portion of the main casing  2  is formed of a cover that is opened and closed to expose or cover the fixing unit  40 . 
     &lt;Configuration of Pressing Member&gt; 
       FIG. 3  is a side cross-sectional view illustrating a front portion of a process cartridge and a rear portion of a front cover in a state where the process cartridge is attached to a main casing and the front cover  11  is closed.  FIG. 4  is a cross-sectional view taken along Line IV-IV of  FIG. 3 , which illustrates a state where a developing-frame terminal comes in contact with a main-body terminal 
     As shown in  FIGS. 3 and 4 , pressing members  70  are disposed at plural positions of the photoconductor frame  31 A in an axis direction of the developing roller  36 , that is, at two positions in the vicinity of the inside of both side walls of the photoconductor frame  31 A. The pressing members  70  are symmetrically disposed with respect to a plane passing through the center position in the axis direction of the developing roller  36  and perpendicular to the axis direction. Accordingly, as described later, the developer cartridge  33  is pressed to the photoconductive drum  32  with a force distributed uniformly in the axis direction. 
     Each pressing member  70  includes a pressing-member supporting portion  701  protruding from the photoconductor frame  31 A, a spring  702 , and a spring cover  703 . The pressing-member supporting portion  701  is formed in a concave shape that extends from the front to the rear and the end is divided into two branches and is spread slightly upward. The spring  702  is attached to the bottom of the concave shape. The spring cover  703  surrounds the end of the pressing-member supporting portion  701  to which the spring  702  is attached and engages with the pressing-member supporting portion  701  so as to be slidable in the anteroposterior direction. A compression coil spring is employed as the spring  702 . 
     &lt;Main-body Terminal&gt; 
     As shown in  FIG. 3 , the inner surface of the front cover  11 , that is, the surface opposed to the process cartridge  30 , is provided with a main-body terminal  19 . The main-body terminal  19  is connected to a controller  6  (an electric circuit) and disposed in the main body. 
     &lt;Inner Terminal and Outer Terminal&gt; 
     The end of each of the spring covers  703  is formed flat and an inner terminal  61  is disposed on the rear surface thereof. An outer terminal  62  is disposed on the front surface of the photoconductor frame  31 A, that is, on the outer surface on a side of the front cover  11 . 
     The inner terminals  61  and the outer terminal  62  are electrically connected to each other through a contact of a metal plate or a wire. In the example shown in  FIG. 3 , the outer terminal  62  is exposed partially from the hole formed in the front wall of the photoconductor frame  31 A to the inside of the photoconductor frame  31 A and the exposed portion is connected to the inner terminals  61  through wires. 
     The outer terminal  62  is disposed to come in contact with the main-body terminal  19 . In the example shown in  FIG. 4 , the main-body terminal  19  comes in contact with the outer terminal  62 , in a state where the process cartridge  30  is attached to the main casing  2  and the front cover  11  is closed. 
     &lt;Developing-Frame Terminal&gt; 
     As shown in  FIG. 3 , memory units  52  and developing-frame terminals  51  are disposed on the outer surface of the developing frame  33 A. The number of memory units  52  may be arbitrary. 
     The developing-frame terminals  51  are respectively electrically connected to the memory units  52  through the contacts of metal plates or wires. In the example shown in  FIG. 3 , the memory units  52  are respectively disposed on the rear surfaces of prism-shaped protrusions  53 . Each of the prism-shaped protrusions  53  protrudes externally from the side surface of the developing frame  33 A. The developing-frame terminals  51  are respectively disposed on the front surfaces of the prism-shaped protrusions  53 . The developing-frame terminals  51  are drawn into the lower sides of the protrusions  53  and are electrically connected to the memory units  52 , respectively. 
     Each of the protrusion  53  has an inclined surface of which the lower side goes up toward the front. When the developer cartridge  33  is pushed into the photoconductor frame  31 A from the upside, the inclined surfaces enter the lower sides while contracting the pressing members  70 . 
     Each of the developing-frame terminals  51  is disposed at a position opposed to the inner terminal  61  in a state where the developer cartridge  33  is attached to the photoconductor frame  31 A. More specifically, each of the developing-frame terminals  51  is disposed to come in contact with the respective one of inner terminals  61  at a position which is closer to the photoconductive drum  32  than the position of the respective one of inner terminals  61  when the respective one of springs  702  is the shortest and more distant from the photoconductive drum  32  than the position of the respective one of inner terminals  61  when the respective one of springs  702  is not pressed. 
     Operations of the photoconductor cartridge  31 , the developer cartridge  33 , and the image forming device  1  will be described. 
     The developer cartridge  33  shown in  FIG. 2  is attached to the photoconductor frame  31 A to constitute the process cartridge  30 . 
     When the developer cartridge  33  is attached to the photoconductor frame  31 A, the springs  702  of the pressing members  70  disposed at plural positions inside the photoconductor frame  31 A are pressed to the protrusions  53  disposed at plural positions outside the developing frame  33 A and are contracted. 
     As shown in  FIG. 3 , when the developer cartridge  33  is completely attached to the photoconductor frame  31 A, the expanding pressure of the springs  702  of the pressing members  70  is always applied to the protrusions  53  and thus the pressing force toward the photoconductive drum  32  is applied to the developing frame  33 A (pressing operation). By means of the pressing operation, the developing roller  36  supported by the developing frame  33 A is pressed to and comes in contact with the photoconductive drum  32  (pressed state). Since the pressing members  70  are disposed symmetrically at two positions of the photoconductor frame  31 A in the axis direction of the developing roller  36 , the developing roller  36  is pressed to the photoconductive drum  32  uniformly in the axis direction. 
     By means of the pressing operation, the developing roller  36  is pressed to the photoconductive drum  32  and the developing-frame terminals  51  disposed at the protrusions  53  come in contact with the inner terminals  61  disposed on the surfaces of the spring covers  703  of the pressing members  70 . 
     When the front cover  11  is opened and the process cartridge  30  is attached to the main casing  2  through the opening and thereafter the front cover  11  is closed, as shown in  FIGS. 3 and 4 , the main-body terminal  19  disposed at the front cover  11  comes in contact with the outer terminal  62  disposed at the outer front portion of the photoconductor frame  31 A. 
     In the pressed state, the memory units  52  are connected to the controller  6  of the main body through the developing-frame terminals  51 , the inner terminals  61 , the outer terminal  62 , and the main-body terminal  19 . 
     In the image forming device  1  according to this embodiment, since the inner terminals  61  are respectively disposed at the pressing members  70 , a simple configuration is obtained. The inner terminals  61  disposed at the pressing members  70  respectively come in contact with the developing-frame terminals  51  and the pressing members  70  press the developing frame  33 A to the photoconductive drum  32 , thereby matching a pressing position for pressing the developing roller  36  to the photoconductive drum  32  with an electrical connection position for the memory units  52 . 
     Since the contact pressure when the main-body terminal  19  comes in contact with the outer terminal  62  is relatively small and acts on the entire process cartridge, it does not prevent the pressing members  70  from uniformly pressing the developing roller  36  to the photoconductive drum  32 . 
     (Second Embodiment) 
     The basic configuration of an image forming device according to a second embodiment of the invention is the same as the first embodiment and thus only different points are described. 
       FIG. 5  is a side cross-sectional view illustrating a front portion of a process cartridge and a rear portion of a front cover in a state where the process cartridge is attached to the main casing and the front cover is closed. 
     &lt;Arrangement of Pressing Members&gt; 
     As shown in  FIG. 5 , each pressing member  70  includes a pressing-member supporting portion  701 , a spring  702 , and a spring cover  703 , similarly to the first embodiment. 
     The pressing members  70  are disposed symmetrically at two positions outside both side walls of the developing frame  33 A (only one position is shown). 
     &lt;Developing-Frame Terminal&gt; 
     The end of the spring cover  703  of each pressing member  70  is formed flat, and each of developing-frame terminals  51  is disposed on the outer (front) surface thereof Each of the memory units  52  is disposed at the pressing member  70  as a part of the developing frame  33 A. The memory units  52  are electrically connected to the developing-frame terminal  51 . 
     &lt;Inner Terminal and Outer terminal&gt; 
     As shown in  FIG. 5 , the inner terminals  61  are disposed on the inner surface of the front wall of the photoconductor frame  31 A so as to respectively come in contact with the developing-frame terminals  51  in a state where the developer cartridge  33  is attached to the photoconductor frame  31 A. 
     The outer terminal  62  is disposed on the outer surface of the photoconductor frame  31 A and the inner terminals  61  and the outer terminal  62  are electrically connected to each other through the contact of a metal plate or a wire. In the example shown in  FIG. 5 , the outer terminal  62  is exposed partially from the hole formed in the photoconductor frame  31 A to the inside of the photoconductor frame  31 A and the exposed portion of the outer terminal  62  is connected to the inner terminals  61  through wires. 
     The outer terminal  62  is disposed to come in contact with the main-body terminal  19 . In the example shown in  FIG. 5 , the main-body terminal  19  comes in contact with the outer terminal  62 , in a state where the photoconductor cartridge  31  is attached to the main casing  2  and the front cover  11  is closed. 
     The main-body terminal  71  serves as an external electric contact of the outer terminal  62 . 
     The developing-frame terminals  51  are disposed at a position where the developer cartridge  33  can be pressed to the photoconductive drum  32  with the expanding pressure of the springs  702  of the pressing members  70  while coming in contact with the inner terminals  61 , in a state where the developer cartridge  33  is attached to the photoconductor frame  31 A. That is, each of the developing-frame terminals  51  is disposed to come in contact with the respective one of inner terminals  61  at a position which is more distant from the photoconductive drum  32  than the position of the respective one of inner terminals  61  when the respective one of springs  702  is the shortest and closer to the photoconductive drum  32  than the position of the respective one of inner terminals  61  when the respective one of springs  702  is not pressed. 
     The operations of the photoconductor cartridge  31 , the developer cartridge  33 , and the image forming device  1  are basically equal to those of the first embodiment, except that the pressing members  70  are disposed at the developing frame  33 A and the directions of the pressing members  70  are inverted. 
     When the developer cartridge  33  is attached to the photoconductor frame  31 A, the springs  702  of the pressing members  70  disposed at the plural positions outside the developing frame  33 A are pressed to the inner terminals  61  disposed at plural positions inside the photoconductor frame  31 A and are contracted. 
     As shown in  FIG. 5 , when the developer cartridge  33  is completely attached to the photoconductor frame  31 A, the expanding pressure of the springs  702  of the pressing members  70  is always applied to the inner terminals  61 . The expanding pressure acts in a direction in which the developing frame  33 A is pressed to the photoconductive drum  32  (pressing operation). By means of the pressing operation, the developing roller  36  supported by the developing frame  33 A is pressed to the photoconductive drum  32  and comes in contact therewith (pressed state). Since the pressing members  70  are disposed symmetrically at the plural positions of the developing frame  33 A in the axis direction of the developing roller  36 , the developing roller  36  is pressed to the photoconductive drum  32  uniformly in the axis direction. 
     In the image forming device  1  according to this embodiment, since the developing-frame terminals  51  are disposed at the pressing members  70 , a simple and compact configuration is obtained. Since the developing-frame terminals  51  disposed at the pressing members  70  come in contact with the inner terminals  61  and presses the developing frame  33 A to the photoconductive drum  32 , it is possible to match the pressing positions with the electrical connection positions. Since the contact pressure when the main-body terminal  19  comes in contact with the outer terminal  62  is relatively small and acts on the entire process cartridge, it does not prevent the pressing members  70  from uniformly pressing the developing roller  36  to the photoconductive drum  32 . 
     (Third Embodiment) 
     The basic configurations of an image forming device according to a third embodiment of the invention are the same as the first embodiment and thus only different points are described below. 
       FIG. 6  is a perspective view illustrating a positional relation between the front cover  11  and the process cartridge  30 .  FIG. 7  is a side cross-sectional view illustrating the process cartridge  30  and the front cover  11  in a state where the process cartridge  30  is attached to the main casing  2  and the front cover  11  is closed. 
     In this embodiment, the photoconductive drum  32  may be disposed in the photoconductor frame  31 A or the photoconductor frame  31 A may not be provided. 
     &lt;Pressing Members&gt; 
     The configuration of the pressing members  70  is the same as the first and second embodiments and thus the arrangement of the pressing members are described. 
     As shown in  FIGS. 6 and 7 , the pressing members  70  are disposed on the inner surface of the front cover  11 , that is, the surface opposed to the process cartridge  30 . The pressing members  70  are disposed at plural positions in the axis direction of the developing roller  36 . 
     As shown in  FIG. 6 , it is preferable that the pressing members  70  are disposed at plural positions to be symmetric with respect to a plane passing through the center position in the axis direction of the developing roller  36  and perpendicular to the axis direction. 
     &lt;Main-body Terminal&gt; 
     The ends of the spring covers  703  of the pressing members  70  are formed flat, and the main-body terminals  71  are respectively disposed on the flat surfaces to protrude therefrom. The main-body terminals  71  are electrically connected to the controller  6  disposed in the main body. 
     &lt;Developing-frame Terminal&gt; 
     As shown in  FIGS. 6 and 7 , the developing-frame terminals  51  are disposed at positions, which are exposed from the photoconductor frame  31 A when it is attached to the photoconductor frame  31 A, on the outer surface of the front portion of the developing frame  33 A. As shown in  FIGS. 6 and 7 , the developing-frame terminals  51  are disposed at positions where they come in contact with the main-body terminals  71  disposed at the spring covers  703  of the pressing members  70 , in the state where the front cover  11  is closed. 
     The developing-frame terminals  51  are electrically connected to the memory unit  52  disposed on the front surface of the developing frame  33 A through wires. 
     Operations of the image forming device  1  having the above-mentioned configuration will be described. 
     The developer cartridge  33  is attached to the photoconductor frame  31 A and the resultant structure is attached to the main body of the image forming device  1 . When the front cover  11  is closed, the pressing members  70  come in contact with the developing-frame terminals  51 . Then, the springs  702  of the pressing members  70  are pressed and contracted by the developing-frame terminals  51 . 
     As shown in  FIG. 7 , in the state where the front cover  11  is closed, the expanding pressure of the springs  702  of the pressing members  70  is always applied to the developing-frame terminals  51  and a pressing force toward the photoconductive drum  32  is applied to the developing frame  33 A. By means of the pressing force, the developing roller  36  supported by the developing frame  33 A is pressed to the photoconductive drum  32  and comes in contact therewith (pressed state). Since the pressing members  70  are disposed at plural positions of the front cover  11  in the axis direction of the developing roller  36  and applies the pressing force thereto, the developing roller  36  is pressed to the photoconductive drum  32  uniformly in the axis direction. 
     In this pressed state, since the developing-frame terminals  51  come in contact with the main-body terminals  71  disposed on the surfaces of the spring covers  703  of the pressing members  70 , the memory unit  52  is connected to the controller  6  disposed in the main body through the developing-frame terminals  51  and the main-body terminals  71 . 
     In the image forming device  1  according to this embodiment, since the main-body terminals  71  are disposed at the pressing members  70 , a simple configuration is obtained. Since the main-body terminals  71  disposed at n the pressing members  70  come in contact with the developing-frame terminals  51  and press the developing frame  33 A to the photoconductive drum  32 , it is possible to match the pressing positions with the electrical connection positions, thereby not affecting the pressing force of the developing roller  36  supported by the developing frame  33 A to the photoconductive drum  32 . 
     Although the embodiments of the invention have been described, the invention is not limited to the embodiments, but may be properly modified in various forms. For example, in the above-mentioned embodiments, a leaf spring shape is employed as an example of a terminal, the invention is not limited to it, but a pin shape may be employed. 
     Further, in the embodiments, the pressing members  70  are disposed at two positions, but three or more pressing members may be provided. In this case, by disposing the pressing members to be as symmetric as possible, it is possible to press the developing roller  36  to the photoconductive drum  32  uniformly in the axis direction. 
     In the embodiments, the terminals are disposed at all the pressing members  70 , but the terminals may not be disposed at all the pressing members  70 . For example, one terminal may be disposed as an electrical contact only at one pressing member  70 . 
     In the above-mentioned embodiments, a combination of the compression coil spring and the supporting member is employed as an example of the pressing member, but the invention is not limited to it, and any member may be used so long as it can perform the pressing with high precision. That is, the materials or structures may be properly modified without departing from the technical spirit of the invention. 
     In the embodiments, the photoconductor cartridge are exemplified as a photoconductor unit detachably attached to the image forming device. However, an unexchangeable photoconductor unit may be provided in the image forming apparatus.