Abstract:
A cartridge according to one aspect of the invention is detachably attachable to a main body including a first terminal. The cartridge comprises: a case; a memory device configured to store information concerning the cartridge; a cover member configured to cover a part of the case and movably supported on the case to allow a relative movement to the case; and a second terminal provided at the cover member and electrically connected to the memory device. In a state where the cartridge is attached to the main body, the second terminal contacts with the first terminal of the main body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2007-083508, filed on Mar. 28, 2007, the entire contents of which are incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    This invention relates to an image forming device, such as a laser printer, and a cartridge detachably attachable thereto. 
       BACKGROUND 
       [0003]    An image forming device, such as a laser printer, generally includes a main body to which a cartridge detachably attachable. 
         [0004]    As an example of such a cartridge, JP-A-10-069140 discloses a process cartridge described including a process cartridge connector having an electric device such as IC memory so that necessary information can be input/output to/from the IC memory. The process cartridge connector is exposed so that a connection terminal faces downward. When the process cartridge is attached to the main body, the process cartridge connector is connected to a main body connector. Accordingly, information is transferred between the IC memory and the main body. 
         [0005]    In the process cartridge described in JP-A-10-069140, as the process cartridge connector is connected to the main body connector, attachment of the process cartridge to the main body is complete and thus abutment pressure from the main body connector acts directly on the process cartridge. In this case, the attachment position of the process cartridge to the main body may shift. 
       SUMMARY 
       [0006]    One aspect of the invention has an object to provide a cartridge capable of being reliably positioned to a main body without affecting connection of a first terminal and a second terminal, and an image forming device to which the cartridge is detachably attachable. 
         [0007]    According to an aspect of the invention, there is provided a cartridge detachably attachable to a main body including a first terminal, said cartridge comprising: a case; a memory device configured to store information concerning the cartridge; a cover member configured to cover a part of the case and movably supported on the case to allow a relative movement to the case; and a second terminal provided at the cover member and electrically connected to the memory device, wherein, in a state where the cartridge is attached to the main body, the second terminal contacts with the first terminal of the main body. 
         [0008]    According to another aspect of the invention, there is provided an image forming device comprising: a first terminal; and a main body to which a cartridge is detachably attachable, wherein the cartridge comprises: a case; a memory device configured to store information concerning the cartridge; a cover member configured to cover a part of the case and movably supported on the case to allow a relative movement to the case; and a second terminal provided at the cover member and electrically connected to the memory device, wherein, in a state where the cartridge is attached to the main body, the first terminal contacts with the second terminal of the cartridge. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a cross-sectional side view to show a laser printer as an example of an image forming device according to one embodiment of the invention; 
           [0010]      FIG. 2  shows the laser printer shown in  FIG. 1  in which a process cartridge is attached to and detached from a main body casing as an example of a main body; 
           [0011]      FIG. 3  is a perspective view of a drum shutter; 
           [0012]      FIG. 4  is a side view of the process cartridge in which a developer cartridge is attached to and detached from a drum cartridge; and 
           [0013]      FIGS. 5A and 5B  are perspective views of a developer cover,  FIG. 5A  shows the developer cover positioned at a cover position and  FIG. 5B  shows the developing cover positioned at an exposure position. 
       
    
    
     DESCRIPTION 
     1. General Configuration of Laser Printer 
       [0014]      FIG. 1  is a cross-sectional side view to show a laser printer as an example of an image forming device according to one embodiment of the invention.  FIG. 2  shows the laser printer shown in  FIG. 1  in which a process cartridge is attached to and detached from a main body casing as an example of a main body.  FIG. 3  is a perspective view of a drum shutter. 
         [0015]    A laser printer  1  includes a main body casing  2  and a sheet feed unit  3 , an image formation unit  4 , and a sheet discharge unit  5  provided in the main body casing  2  as shown in  FIG. 1 . 
         [0016]    (1) Main Body Casing 
         [0017]    The main body casing  2  has a substantially box shape and has an opening  6  formed through one side wall of the main body casing  2 . The main body casing  2  includes a front cover  7  configured to open and close the opening  6 . In a state where the front cover  7  is opened, a process cartridge  17  (described later) can be attached to or detached from the main body casing  2 . 
         [0018]    In the description to follow, the side where the front cover  7  is provided is “front” and the opposite side is “rear.” The front in the sheet thickness direction in  FIG. 1  is the left and the back in the sheet thickness direction in  FIG. 1  is the right. The left and right direction (side to side direction) is synonymous with the width direction. 
         [0019]    (2) Sheet Feed Unit 
         [0020]    The sheet feed unit  3  includes a sheet feed tray  9 , a sheet feed roller  10 , a sheet powder removing roller  12 , a pair of registration rollers  14 , and a sheet press plate  15 . The sheet feed roller  10  is configured to feed a sheet at the top of stack of sheets placed on the sheet press plate  15  one by one at one time. The sheet  8  fed by the sheet feed roller  10  passes through the sheet powder removing roller  12  and the registration rollers  14  and then is conveyed to a transfer position (described later) of the image forming unit  4 . 
         [0021]    (3) Image Forming Unit 
         [0022]    The image forming unit  4  includes a scanner unit  16 , the process cartridge  17 , and a fixing unit  18 . 
         [0023]    (3-1) Scanner Unit 
         [0024]    The scanner unit  16  is provided in an upper portion of the main body casing  2  and includes a laser beam emission unit (not shown), a rotated polygon mirror  19 , a plurality of lenses  20 , and a plurality of reflecting mirrors  21 . A laser beam emitted from the laser beam emission unit based on image data is reflected on the polygon mirror  19  and then passes through the lenses  20  and reflected on the reflecting mirrors  21 . Thereafter, the laser beam is scanned over the surface of a photoconductive drum  25  serving as an example of a rotation body (described later) of the process cartridge  17 , as indicated by the dashed line in  FIG. 1 . 
         [0025]    (3-2) Process Cartridge 
         [0026]    The process cartridge  17  is detachably attachable to the main body casing  2  and is placed below the scanner unit  16  in the main body casing  2  when the process cartridge  17  is attached to the main body casing  2 . 
         [0027]    The process cartridge  17  includes the drum cartridge  22  and the developer cartridge  31 . The developer cartridge  31  is detachably attachable to a cartridge storing portion  33  of the drum cartridge  22 . The drum cartridge  22  and the developer cartridge  31  are an example of a cartridge. 
         [0028]    The drum cartridge  22  has a substantially box shape as shown in  FIG. 3 . The drum cartridge  22  includes a drum frame  23  forming the contour of the drum cartridge. A roughly rear side half of the drum frame  23  is adopted as a drum storing portion  32  and a roughly front side half is adopted as the cartridge storing portion  33 . 
         [0029]    The drum storing portion  32  has a substantially box shape with an opening formed through both front and rear side faces and includes the photoconductive drum  25 , a scorotron charger  26 , and a transfer roller  27 . An opening formed through the rear face of the drum storing portion  32  is called a drum rear opening  77  and an opening formed through the front face of the drum storing portion  32  is called a drum front opening  63 . Each of the drum rear opening  77  and the drum front opening  63  has a substantially rectangle relatively long in the width direction. 
         [0030]    The photoconductive drum  25  is relatively long in the width direction and is placed so that it is partially exposed from the drum frame  23  to the rear in the drum rear opening  77 . The portion exposed from the drum rear opening  77  in the photoconductive drum  25  is called a drum exposure portion  75  as an example of an exposure portion. The photoconductive drum  25  is rotatably supported on the drum frame  23 . The scorotron charger  26  is supported on the drum frame  23  with a spacing from the photoconductive drum  25  above the photoconductive drum  25 . The transfer roller  27  is placed facing the photoconductive drum  25  from below the photoconductive drum  25  and is rotatably supported on the drum frame  23 . 
         [0031]    The cartridge storing portion  33  is formed to have a closed-end frame with the upper face opened. A drum grip  24  extending to the front is formed in the upper end portion of the front end portion of the cartridge storing portion  33 . By grasping the drum grip  24 , the user can attach or detach the drum cartridge  22  to or from the main body casing  2  singly or as the process cartridge  17  with the developer cartridge  31  attached to the cartridge storing portion  33 . The drum front opening  63  of the drum storing portion  32  is exposed in the cartridge storing portion  33 , and the front portion of the photoconductive drum  25  is exposed to the inside of the cartridge storing portion  33  through the drum front opening  63 . The upper registration roller  14  of the paired registration rollers  14  described above is rotatably supported on the bottom of the cartridge storing portion  33 . 
         [0032]    The developer cartridge  31  is detachably attached to the drum cartridge  22  in the cartridge storing portion  33 . 
         [0033]    The developer cartridge  31  has a substantially box shape. The developer cartridge  31  includes a developing frame  28  as an example of a case forming the contour of the developer cartridge  31 . An opening (called a developing opening  59 ) of almost the same shape as the drum front opening  63  is formed through the rear face of the developing frame  28 . The inside of the developing frame  28  is partitioned into a toner storage chamber  29  on the front and a developing chamber  30  on the rear. The toner storage chamber  29  and the developing chamber  30  communicate with each other. A developing grip  35  extending to the front is formed in the upper end portion of the front end portion of the developing frame  28 . By grasping the developing grip  35 , the user can attach or detach the developer cartridge  31  to or from the drum cartridge  22 . 
         [0034]    The developing chamber  30  includes a supply roller  36 , a developing roller  37  as an example of a developer carrier, and a layer thickness regulation blade  38 . 
         [0035]    The developing roller  37  is relatively long in the width direction and is placed so that the developing roller  37  is partially exposed from the developing frame  28  to the rear in the developing opening  59 . The portion exposed from the developing opening  59  in the developing roller  37  is called a developing exposure portion  76  as an example of an exposure portion. The developing opening  59  and the drum front opening  63  face each other in a state where the developer cartridge  31  is attached to the drum cartridge  22 . In this state, the developing roller  37  is in contact with the photoconductive drum  25  from the front in the developing exposure portion  76 . The developing roller  37  and the supply roller  36  are rotatably supported on the developing frame  28 . Both end portions in the width direction of the rotation shaft of the developing roller  37  are exposed from both side walls in the width direction of the developing frame  28 . The layer thickness regulation blade  38  includes a plate spring member  45  formed like a thin plate and press contact rubber  46  provided in a lower end portion of the plate spring member  45 . An upper end portion of the plate spring member  45  is fixed to the developing frame  28  and the press contact rubber  46  presses the surface of the developing roller  37  by the elastic force of the plate spring member  45 . 
         [0036]    An agitator is rotatably provided in the toner storage chamber  29 . Nonmagnetic single-component toner having positive electrostatic property as an example of a developer is stored in the toner storage chamber  29 . 
         [0037]    The toner in the toner accommodation chamber  29  is agitated by rotation of the agitator  40  and is released into the developing chamber  30  and is supplied to the supply roller  36 , as shown in  FIG. 1 . The toner supplied to the supply roller  36  is supplied to the developing roller  37  by rotation of the supply roller  36 . At this time, the toner is frictionally charged to the positive polarity between the supply roller  36  and the developing roller  37 . Subsequently, the toner supplied to the developing roller  37  enters the nip between the press contact rubber  46  and the developing roller  37  with rotation of the developing roller  37  and is carried on the surface of the developing roller  37  as a thin layer while the layer thickness is regulated between the press contact rubber  46  and the developing roller  37 . 
         [0038]    The surface of the photoconductive drum  25  is positively charged uniformly by the scorotron charger  26  with rotation of the photoconductive drum  25  and then is exposed to light by a laser beam from the scanner unit  16  and an electrostatic latent image based on the image data is formed. Next, when the toner carried on the surface of the developing roller  37  faces the photoconductive drum  25  and comes in contact therewith by rotation of the developing roller  37 , the toner is supplied to the electrostatic latent image formed on the surface of the photoconductive drum  25 . Accordingly, the electrostatic latent image is developed (is made visible) and the toner image is carried on the surface of the photoconductive drum  25 . The toner image is transferred onto the sheet  8  conveyed to the nip between the photoconductive drum  25  and the transfer roller  27  (transfer position). The sheet  8  onto which the toner image is transferred is conveyed to the fixing unit  18 . 
         [0039]    (3-3) Fixing Unit 
         [0040]    The fixing unit  18  is provided at the rear of the process cartridge  17 . The fixing unit  18  includes a heating roller  48 , a pressurization roller  49  pressed against the heating roller  48  from below, and a pair of conveying rollers  50  placed at the rear of them. 
         [0041]    In the fixing unit  18 , the toner transferred onto the sheet  8  at the transfer position is thermally fixed while the sheet  8  passes through the nip between the heating roller  48  and the pressurization roller  49  and then the sheet  8  is conveyed to the sheet discharge unit  5  by the pair of conveying rollers  50 . 
         [0042]    (4) Sheet Discharge Unit 
         [0043]    The sheet discharge unit  5  includes a sheet discharge path  51 , a sheet discharge roller  52 , and a sheet discharge tray  53 . The sheet  8  conveyed from the fixing unit  18  to the sheet discharge path  51  is conveyed from the sheet discharge path  51  to the sheet discharge roller  52  and is discharged onto the sheet discharge tray  53  by the sheet discharge roller  52 . 
       2. Details of Main Body Casing and Drum Cartridge 
       [0044]    (1) Main Body Casing 
         [0045]    In the main body casing  2 , a guide wall  39  extending substantially along the back and forth direction is provided slightly above the process cartridge  17  attached to the main body casing  2 . The lower face of the guide wall  39  is partitioned by a horizontal portion  41  and an inclined portion  42 . The inclined portion  42  is a slope extending downward to the slanting rear from the opening  6  to the inside of the main body casing  2 , and the front end corresponds to the upper end of the opening  6 . The horizontal portion  41  is a substantially horizontal plane extending from the rear end of the inclined portion  42  to the rear along the back and forth direction (or slightly downward inclined). A main body terminal  54  as an example of a first terminal is provided in the vicinity of the rear end of the horizontal portion  41 . The main body terminal  54  is formed of an electrical conductive plate spring having elasticity or the like and projects downward from the horizontal portion  41 . The main body terminal  54  is connected to a CPU (not shown) provided in the main body casing  2 . 
         [0046]    (2) Drum Cartridge 
         [0047]    The drum cartridge  22  includes a drum cover  44  as an example of a cover member on the rear face of the drum frame  23  (drum storing portion  32 ). 
         [0048]    The drum cover  44  is formed like a thin plate having a substantially inverted-J shape in the left sectional view, for example, as shown in  FIG. 3 . For the convenience of the description, the upper flat portion of the drum cover  44  is called as a flat portion  47  and the lower bent portion of the drum cover  44  is called as a bend portion  55 . The bend portion  55  is bent downward in a direction toward the rear face of the drum frame  23  (namely, the front in  FIG. 3 ). In the drum cover  44 , a memory device  64  and a drum terminal  65  as an example of a second terminal electrically connected to the memory device  64  are provided on a side face on the opposite side to the side opposed to the rear face of the drum frame  23  (namely, the rear face in  FIG. 3 ). The memory device  64  is memory for storing information concerning the drum cartridge  22  (for example, drive condition of the photoconductive drum  25 , etc.,) in such a manner that the information can be read and can be written. The memory device  64  and the drum terminal  65  may be formed in one piece, i.e., the drum terminal  65  may be integrated with the memory device  64 . The memory device  64  may be provided in the drum frame  23  rather than the drum cover  44 . In this case, the memory device  64  is electrically connected to the drum terminal  65  of the drum cover  44  by an electric wire or a plate. 
         [0049]    A swing shaft  56  extending in the width direction is inserted into the drum cover  44 . The drum cover  44  is supported in the rear end portion of the upper wall of the drum frame  23  through the swing shaft  56  and swingable around the swing shaft  56  (see  FIG. 1 ). In particular, the drum cover  44  can move between a cover position (an example of a first position) and an exposure position (an example of a second position) described later. The swing shaft  56  is roughly at the center position in the up and down direction of the flat portion  47 ; hereinafter, in the flat portion  47 , the portion above the swing shaft  56  will be referred as an upper portion  57  and the portion below the swing shaft  56  will be referred as a lower portion  58 . 
         [0050]    When the drum cover  44  is positioned at the cover position, the lower end portion of the bend portion  55  abuts the rear end portion of the bottom wall of the drum frame  23  from the rear, and the drum cover  44  covers the drum rear opening  77  formed through the drum frame  23  and the drum exposure portion  75  exposed from the drum rear opening  77  from the rear, as indicated by the solid line in  FIG. 2 . At this time, the drum cover  44  is made upright roughly along the up and down direction so that the upper portion  57  projects upward to the slanting front from the upper wall of the drum frame  23 . The drum terminal  65  faces backward. 
         [0051]    On the other hand, when the drum cover  44  is positioned at the exposure position, the lower end portion of the bend portion  55  is away from the rear end portion of the bottom wall of the drum frame  23  to the rear and the drum cover  44  exposes the drum rear opening  77  and the drum exposure portion  75  to the rear, as shown in  FIG. 1 . The drum cover  44  is inclined roughly along the back and forth direction so that the flat portion  47  is almost along the upper wall of the drum frame  23 . When the drum cover  44  is positioned at the exposure position, the drum terminal  65  faces upward. 
         [0052]    Thus, the drum cover  44  can move relative to the drum frame  23 . 
         [0053]    A spring  66  (an example of an urging member) is intervened between the rear end portion of the upper wall of the drum frame  23  and the upper portion  57  of the drum cover  44  for urging the upper portion  57  of the drum cover  44  so as to project upward from the upper wall of the drum frame  23 , as shown in  FIG. 2 . Accordingly, the drum cover  44  is urged so as to position at the cover position normally (namely, when the drum cartridge  22  is outside the main body casing  2 ). The drum cover  44  protects the drum exposure portion  75  of the photoconductive drum  25  in a state where it positions at the cover position. 
         [0054]    (3) Attaching and Detaching of Process Cartridge to and from Main Body Casing 
         [0055]    The drum cartridge  22  including the drum cover  44  is attached to the main body casing  2 . For the convenience of the description, the description shows an example where the drum cartridge  22  to which the developer cartridge  31  is attached, namely, the process cartridge  17  is attached to the main body casing  2 , rather than the drum cartridge  22  is solely attached to the main body casing  2 . However, the drum cartridge  22  solely may also be attached to and detached from the main body casing  2 . The drum cover  44  is positioned at the cover position when attachment of the process cartridge  17  is started. 
         [0056]    First, the front cover  7  is opened for opening the opening  6  and the process cartridge  17  is inserted into the main body casing  2  from the front roughly along the horizontal direction. At this time, the upper portion  57  of the drum cover  44  at the cover position is opposed to the inclined portion  42  of the guide wall  39  with a spacing in the back and forth direction. Thus, if the process cartridge  17  is continuously inserted into the main body casing  2  roughly along the horizontal direction, the upper portion  57  is abutted against the inclined portion  42 . Accordingly, the drum cover  44  starts to swing toward the exposure position against the urging force of the spring  66  (see the drum cover  44  indicated by the dotted line in  FIG. 2 ). If the process cartridge  17  is continuously inserted into the main body casing  2  roughly along the horizontal direction, the upper portion  57  is abutted against the horizontal portion  41  following the inclined portion  42  and the drum cover  44  swings to the exposure position (see the drum cover  44  indicated by the alternate long and short dash line in  FIG. 2 ). Since the horizontal portion  41  is a roughly horizontal plane as described above, the drum cover  44  is maintained at the exposure position while the upper portion  57  is abutted against the horizontal portion  41 . When inserting of the process cartridge  17  into the main body casing  2  stops, placing the process cartridge  17  in the main body casing  2  is complete as shown in  FIG. 1 . At this time, the drum cover  44  is positioned at the exposure position and thus the drum terminal  65  faces upward as described above and abuts the main body terminal  54 . Accordingly, the drum terminal  65  and the main body terminal  54  are electrically connected, so that the CPU (not shown) and the memory device  64  provided in the main body casing  2  are electrically connected. In this state, the CPU (not shown) can read the information stored in the memory device  64  and can rewrite the information stored in the memory device  64  in response to the image formation operation. 
         [0057]    On the other hand, the front cover  7  is opened in a state where the process cartridge  17  is attached to the main body casing  2 , and the process cartridge  17  is drawn out to the front. Accordingly, the drum terminal  65  is brought away from the main body terminal  54  and thereby electrically disconnected from the main body terminal  54 . The drum cover  44  is continuously at the exposure position as indicated by the alternate long and short dash line in  FIG. 2  in a state where the upper portion  57  is abutted against the horizontal portion  41 . When the process cartridge  17  is drawn out to the front and the upper portion  57  passes through the horizontal portion  41  and is abutted against the inclined portion  42 , the drum cover  44  starts to swing toward the cover position by the urging force of the spring  66  (see the drum cover  44  indicated by the dotted line in  FIG. 2 ). When the upper portion  57  passes through the inclined portion  42 , the drum cover  44  swings to the cover position. When the process cartridge  17  is completely drawn out from the main body casing  2 , detaching the process cartridge  17  from the main body casing  2  is complete. 
       3. Function and Effect of the Embodiment 
       [0058]    As shown in  FIG. 1 , when the drum cover  44  is moved in one direction (in particular, to the exposure position) at the attachment completion position of the process cartridge  17  (in particular, the drum cartridge  22 ) in the main body casing  2 , the drum terminal  65  provided on the drum cover  44  abuts the main body terminal  54 . Then, the drum terminal  65  and the main body terminal  54  are electrically connected and information can be transferred between the memory device  64  and the CPU (not shown) provided in the main body casing  2 . 
         [0059]    When the drum terminal  65  abuts the main body terminal  54 , the abutment pressure received by the drum terminal  65  from the main body terminal  54  is received at the drum cover  44 , so that the abutment pressure can be prevented from acting directly on the drum frame  23  and the drum frame  23  can be prevented from moving from a predetermined attachment completion position. Thus, shift of the attachment position of the process cartridge  17  (drum cartridge  22 ) relative to the main body casing  2  can be prevented. 
         [0060]    Consequently, positioning the process cartridge  17  to the main body casing  2  can be reliably executed without affecting connection of the main body terminal  54  and the drum terminal  65 . 
         [0061]    The drum cover  44  can move between the cover position for covering the drum exposure portion  75  of the photoconductive drum  25  (see the solid line portion in  FIG. 2 ) and the exposure position for exposing the drum exposure portion  75  (see  FIG. 1 ). Thus, when the drum cover  44  is moved to the exposure position, a toner image can be transferred from the photoconductive drum  25  to a sheet  8 , and the sheet  8  with the toner image can pass through the drum rear opening  77  uncovered with the drum cover  44 . On the other hand, when the drum cover  44  is moved to the cover position, the drum exposure portion  75  can be protected (see  FIG. 2 ). Thus, the photoconductive drum  25  as a rotation body rotatably supported on the drum frame  23  is covered with the drum cover  44  at the cover position. 
         [0062]    When the drum cover  44  is positioned at the exposure position, the drum terminal  65  abuts the main body terminal  54  and thus information can be transferred between the memory device  64  and the CPU (not shown) in the main body casing  2  at the same time as the transfer operation described above, so that operability can be improved. 
       4. Modified Examples 
     (1) Modified Example 1 
       [0063]    A developing cover  60  may be provided as an example of a cover member in addition to or in place of the drum cover  44 . The developer cartridge  31  and the drum cartridge  22  when the developing cover  60  is provided will be discussed below. 
         [0064]      FIG. 4  is a side view of the process cartridge in which the developer cartridge is attached to and detached from the drum cartridge.  FIG. 5A  shows the developing cover positioned at a cover position and  FIG. 5B  shows the developing cover positioned at an exposure position. 
         [0065]    (1-1) Developing Cartridge 
         [0066]    The developing cover  60  is included in the developer cartridge  31  and is formed like a thin plate relatively long in an up and down direction and roughly rectangular in the front view, for example, as shown in  FIGS. 5A and 5B . The upper end portion and the lower end portion of the developing cover  60  are formed so as to project one step to both sides in the width direction. The portions projecting to both sides in the width direction in the upper end portion of the developing cover  60  are called upper projection portions  62  (an example of a distal end portion), and the portions projecting to both sides in the width direction in the lower end portion of the developing cover  60  are called lower projection portions  67 . In the developing cover  60 , a through hole  61  of almost the same shape as the developing opening  59  is formed at a position slightly shifted to the lower side from the center of the developing cover  60  in the up and down direction thereof. 
         [0067]    The developing cover  60  is slidably supported in the up and down direction by the rear end portions of both side walls in the width direction of the developing frame  28 . In particular, the portion of the developing cover  60  between the upper projection portions  62  and the lower projection portions  67  in the up and down direction is sandwiched between the rear end portions of both side walls in the width direction of the developing frame  28 . In this state, the developing cover  60  can move between a cover position described later and an exposure position above the cover position. 
         [0068]    When the developing cover  60  is positioned at the cover position, the developing opening  59  is covered with the upper portion above the through hole  61  in the developing cover  60  from the rear, as shown in  FIG. 5A . Accordingly, the developing exposure portion  76  is also covered with the developing cover  60  from the rear. That is, when the developing cover  60  is positioned at the cover position, the developing cover  60  covers the developing opening  59  formed through the developing frame  28  and the developing exposure portion  76  exposed from the developing opening  59  from the rear. The roughly lower half portion of the developing cover  60  projects downward from the developing frame  28 . When the developing cover  60  moves down to the cover position, the upper projection portions  62  abut the rear end portions of both side walls in the width direction of the developing frame  28  from above, so that the developing cover  60  is prevented from further moving from the cover position and dropping out from the developing frame  28 . The developing cover  60  is normally positioned at the cover position under its own weight. 
         [0069]    On the other hand, when the developing cover  60  is positioned at the exposure position, the developing opening  59  faces the through hole  61  in the back and forth direction and communicates with the through hole  61  as shown in  FIG. 5B . Accordingly, the developing exposure portion  76  is exposed to the front through the developing opening  59  and the through hole  61 . That is, when the developing cover  60  is positioned at the exposure position, the developing cover  60  exposes the developing exposure portion  76  to the rear. The roughly upper half portion of the developing cover  60  projects upward from the developing frame  28 . 
         [0070]    Thus, when the developing cover  60  moves from the cover position to the exposure position, the developing cover  60  moves up (an example of a first direction) relative to the developing opening  59 ; when the developing cover  60  moves from the exposure position to the cover position, it moves down relative to the developing opening  59 . This means that the developing cover  60  can make a relative movement to the developing frame  28  containing the developing opening  59 . 
         [0071]    In the developing cover  60 , the above-described memory device  64  is provided above the through hole  61  on a side face on the opposite side to the side opposed to the developing opening  59  (namely, the rear face in  FIGS. 5A and 5B ). The memory device  64  according to modified example 1 stores information concerning the developer cartridge  31  (for example, the toner storage amount, etc.,). A developing terminal  68  as an example of a second terminal electrically connected to the memory device  64  is provided on the upper end face of the developing cover  60 . The memory device  64  and the developing terminal  68  may be formed in one piece. The memory device  64  may be provided in the developing frame  28  rather than the developing cover  60 . In this case, the memory device  64  is electrically connected to the developing terminal  68  of the developing cover  60  by an electric wire or a plate. 
         [0072]    (1-2) Drum Cartridge 
         [0073]    As shown in  FIG. 4 , in the drum cartridge  22 , the upper end faces of both side walls of the cartridge storing portion  33  in the width direction thereof (called guide rails  69 ) are formed so as to incline downward to the slanting rear. The rear end margins of the guide rails  69  are connected roughly to the center in the up and down direction of the front end margins of both side walls of the drum storing portion  32  in the width direction thereof. A concave portion  70  recessed downward to the slanting rear continuous from the rear end margin of the guide rail  69  is formed on both side walls of the drum storing portion  32  in the width direction thereof. Each concave portion  70  pierces the corresponding width direction side wall in the drum storing portion  32  in the width direction. 
         [0074]    A guide groove  71  is formed on the width direction inner faces of both side walls of the drum cartridge  22  in the width direction thereof corresponding to the developing cover  60 . The guide grooves  71  are formed by notching the width direction inner faces of both side walls of the drum cartridge  22  in the width direction thereof from the upper end margins to the lower side. In particular, the groove bottom (lower end face) of each guide groove  71  is formed so that it extends like a circular arc from the rough center position in the back and forth direction of the corresponding guide rail  69  to the rear lower side (this portion is called a circular arc groove bottom  73 ) and then extends to the rear roughly horizontally (this portion is called a horizontal groove bottom  74 ). 
         [0075]    (1-3) Attaching and Detaching of Developing Cartridge to and from Drum Cartridge 
         [0076]    The direction in which the developer cartridge  31  is attached to and detached from the drum cartridge  22  is a direction crossing the horizontal direction (see the thick arrow in  FIG. 4 ). 
         [0077]    The developer cartridge  31  with the developing cover  60  at the cover position (see the solid line indication portion in  FIG. 4 ) is inserted into the cartridge storing portion  33  of the drum cartridge  22  downward to the slanting rear. At this time, first, the corresponding lower projection portions  67  are accepted in the guide grooves  71 . Portions exposed from both side walls of the developing frame  28  in the width direction thereof in the rotation shaft of the developing roller  37  (called exposure shafts  72 ) are placed in the corresponding guide rails  69 . In this state, if the developer cartridge  31  is inserted into the cartridge storing portion  33 , the lower projection portions  67  are guided along the guide grooves  71  (in particular, the circular arc groove bottoms  73 ), the exposure shafts  72  are guided along the guide rails  69 , and the developer cartridge  31  moves downward to the slanting rear. When the lower projection portions  67  pass through the circular arc groove bottoms  73  and arrive at the horizontal groove bottoms  74 , the positions of the lower projection portions  67  in the up and down direction are fixed and it is made impossible for the developing cover  60  to further move down. Thus, if the developer cartridge  31  (in particular, the developing frame  28 ) is further moved down, the developing frame  28  moves down relative to the developing cover  60  of which the downward movement is regulated (see the alternate long and short dash line portion in  FIG. 4 ). Accordingly, the developing cover  60  moves up relative to the developing frame  28  and moves to the exposure position. 
         [0078]    When the exposure shafts  72  pass through the corresponding guide rails  69  and are fitted into the corresponding concave portions  70 , placing the developer cartridge  31  in the drum cartridge  22  is complete (see the dotted line portion in  FIG. 4 ). At this time, the through hole  61  of the developing cover  60  at the exposure position, the developing opening  59 , and the drum front opening  63  face each other and the developing exposure portion  76  of the developing roller  37  comes in contact with the photoconductive drum  25 . The upper end portion of the developing cover  60 , in particular the developing terminal  68  projects upward from each upper wall of the drum frame  23  and the developing frame  28 . Thus, if the drum cartridge  22  to which the developer cartridge  31  is attached, namely, the process cartridge  17  is attached to the main body casing  2 , the developing terminal  68  abuts the main body terminal  54 . Accordingly, the CPU (not shown) provided in the main body casing  2  and the memory device  64  are electrically connected and the CPU (not shown) can read and rewrite the information stored in the memory device  64  as described above. If the process cartridge  17  is detached from the main body casing  2 , the developing terminal  68  is brought away from the main body terminal  54  and thereby electrically disconnected from the main body terminal  54 . 
         [0079]    On the other hand, when the developer cartridge  31  attached to the drum cartridge  22  is drawn out to the front, the developer cartridge  31  moves up to the slanting front. At this time, the lower projection portions  67  are guided along the guide grooves  71  (in particular, the horizontal groove bottoms  74 ) and the exposure shafts  72  are placed out of the concave portions  70  and are guided along the guide rails  69 . The developing cover  60  cannot move up under its own weight; whereas, the developing frame  28  moves up and thus the developing cover  60  moves down relative to the developing frame  28  and moves to the cover position. When the exposure shafts  72  are placed out of the guide rails  69  and the lower projection portions  67  are placed out of the guide grooves  71  (in particular, the circular arc groove bottoms  73 ) and the developer cartridge  31  is completely drawn out from the cartridge storing portion  33 , detaching the developer cartridge  31  from the drum cartridge  22  is complete. 
         [0080]    (1-4) Function and Effect of Modified Example 1 
         [0081]    In modified example 1, the developing cover  60  can move between the cover position for covering the developing exposure portion  76  of the developing roller  37  (see  FIG. 5A ) and the exposure position for exposing the developing exposure portion  76  (see  FIG. 5B ). Thus, if the developing cover  60  is moved to the exposure position, toner can be supplied from the developing exposure portion  76  to the photoconductive drum  25  (see the dotted line portion in  FIG. 4 ) and if the developing cover  60  is moved to the cover position, the developing exposure portion  76  can be protected (see the solid line portion in  FIG. 4 ). Thus, the developing roller  37  as a rotation body rotatably supported on the developing frame  28  is covered with the developing cover  60  at the cover position. 
         [0082]    When the developing cover  60  is positioned at the exposure position, the developing terminal  68  abuts the main body terminal  54  and thus information can be transferred between the memory device  64  and the CPU (not shown) in the main body casing  2  at the same time as the toner supply described above, so that operability can be improved. 
       (2) Modified Example 2 
       [0083]    In the embodiment described above, as the process cartridge  17 , the drum cartridge  22  and the developer cartridge  31  can be separated. However, the process cartridge  17  into which the drum cartridge  22  and the developer cartridge  31  are combined as one piece may be adopted as an example of a cartridge. In this case, the process cartridge  17  is provided with the drum cover  44 , but not with the developing cover  60 . As information concerning the process cartridge  17 , both the information concerning the drum cartridge  22  described above and the information concerning the developer cartridge  31  are stored in the memory device  64  of the drum cover  44 . 
         [0084]    In the embodiment described above, the toner storage chamber  29  and the developing chamber  30  are provided in the developing frame  28  of the developer cartridge  31 , but the portion corresponding to the toner storage chamber  29  may be attached to and detached from the developing frame  28  as a toner cartridge. 
         [0085]    The developer cartridge  31  may also be detachably attachable to the drum cartridge  22  in a state where the drum cartridge  22  is attached to the main body casing  2 . The photoconductive drum  25 , the scorotron charger  26 , and the transfer roller  27  may be provided in the main body casing  2  and the developer cartridge  31  may be detachably attachable to the main body casing  2 . 
       (3) Modified Example 3 
       [0086]    In the embodiment described above, the monochrome laser printer  1  is illustrated; however, for example, the image forming device can also be implemented as a color laser printer (containing tandem type, intermediate transfer type).