Patent Publication Number: US-8121518-B2

Title: Combination in which toner cartridge is removably installed in developing cartridge, which is removably installed in photoconductor cartridge

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 11/382,579, filed May 10, 2006, which claims priority from Japanese Patent Application Nos. 2005-138779, filed on May 11, 2005, and 2005-149750, filed May 23, 2005, the entire subject matter of which is incorporated herein by reference. 
    
    
     FIELD 
     Aspects of the present invention relate to an image forming apparatus of a so-called electronic photographic system that forms an image by developing an electrostatic latent image formed on an image carrier body using toner and causing the image to adhere to a recording medium, and to a process cartridge, a main body cartridge, an image carrier body cartridge, a developing cartridge, and a toner cartridge that can be used in the image forming apparatus. 
     BACKGROUND 
     In the past, image forming apparatuses have included an image carrier body, having a surface on which an electrostatic latent image is formed, a developing roller, which causes toner to adhere to the surface of the image carrier body to develop the electrostatic latent image, a transfer roller, which transfers to a recording medium the toner that has adhered to the surface of the image carrier body by the developing roller, and a toner cartridge, in which the toner is accommodated and that is configured so that it can be installed and removed. 
     In this type of image forming apparatus, when an electrostatic latent image is formed on the surface of the image carrier body, the developing roller causes toner that is held in a toner cartridge to adhere to the surface of the image carrier body to develop the electrostatic latent image. Then, it is possible to form an image that corresponds to the electrostatic latent image on the recording medium by the transfer roller transferring the toner that has adhered to the surface of the image carrier body to the recording medium. 
     In addition, in this type of image forming apparatus, pressure attachment of a developing means such as a developing roller to an image carrier body that uses and OPC (organic photoconductor), etc. is performed using a spring, etc., and the development is performed. However, when the OPC and the developing roller continue to be mutually pressure attached for a long period of time without rotation, there is a possibility of chemical damage to the OPC occurring or of the developing roller becoming permanently deformed. In this regard, it has been proposed that the two be separated by configuring the developing roller and the image carrier body so that they can approach and separate and inserting a wedge member between the developing means and the image carrier body at the time of shipping of the image forming apparatus. 
     SUMMARY 
     Certain aspects of the present invention are directed to a process cartridge. According to one illustrative aspect a process cartridge includes an image carrier body having a surface on which an electrostatic latent image is formed, a developing roller configured to cause toner to adhere to the surface of the image carrier body to develop the electrostatic latent image, and a single or plural separable housing configured to support the image carrier body and the developing roller, the housing configured to allow the developing roller to be attached to said image carrier body and to be detached from said image carrier body in response to a pressing force. Also, the process cartridge includes a toner cartridge, for holding the toner, the toner cartridge being configured to be installed in and removed from the housing, and a pressure attachment device that is configured to attach the image carrier body and the developing roller by applying a pressing force when the toner cartridge is installed in the housing and is configured release the pressure attachment of the image carrier body and the developing roller when the toner cartridge is removed from the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an oblique view that shows the external appearance of a laser printer to according to illustrative aspects of the present invention. 
         FIG. 2  is an oblique view that shows the operation of releasing the lid part of the laser printer of  FIG. 1 . 
         FIG. 3  is a vertical cross sectional view that shows the internal configuration of the laser printer of  FIG. 1 . 
         FIG. 4  is a side surface view that shows the external appearance of the photoconductor cartridge, the developing cartridge, and the toner cartridge of the laser printer of  FIG. 1 . 
         FIG. 5  is an explanatory drawing that shows the configuration of the mechanism that switches between linking and separating of the developing cartridge and the toner cartridge of the laser printer of  FIG. 1 . 
         FIG. 6  is an explanatory drawing that shows an illustrative condition in which the toner cartridge has been installed in the developing cartridge from the front side surface. 
         FIG. 7  is a side surface view that shows the configuration of the photoconductor cartridge of the laser printer and a partial view that shows the configuration from the inner surface side. 
         FIG. 8  is an explanatory drawing that shows displacement of the developing roller according to the installation and removal of the toner cartridge. 
         FIG. 9  is an explanatory drawing that shows an illustrative configuration of the left side inner wall surface of the laser printer main body. 
         FIG. 10  is a left side surface view and a right side surface view, which show illustrative configurations of the developing cartridge and toner cartridge. 
         FIG. 11  is an explanatory drawing that shows an illustrative configuration and action of a modified form of the photoconductor cartridge. 
         FIG. 12  is an explanatory drawing that shows an illustrative configuration and action of a modified form of the toner cartridge. 
         FIG. 13  is an explanatory drawing that shows an illustrative configuration and action of a modified form of a photoconductor cartridge corresponding to the toner cartridge. 
         FIG. 14  is an explanatory drawing that shows an illustrative configuration of a modified form of the laser printer main body. 
     
    
    
     DETAILED DESCRIPTION 
     It is noted that various connections are set forth between elements in the following description. It is noted that these connections in general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. 
     Next, illustrative aspects of the present invention will be explained using the drawings.  FIG. 1  is an oblique view that shows the external appearance of a laser printer  1  functioning as the image forming apparatus according to an illustrative application of the present invention. As shown in  FIG. 1 , a paper feed cassette  3  is installed at the bottom part of the cover  2  that covers the main body of a laser printer  1  from the outer circumference A lid portion  4  of the cover  2  is provided at the front surface (specifically, at the surface arranged in the front at the time of installation of the laser printer  1 ) of the cover  2 . 
     The lid part  4  includes a finger grip part  4   a  at the top of both of the left and right ends. By pulling the finger grip part  4   a , it is possible to open the lid part  4  in a forward direction centering on the hinge  4   b  of the lower end as shown in  FIG. 2 . In addition, as shown in  FIG. 2 , a paper feed cassette  3  is provided so that it can be pulled out toward the front. As such, the paper feed cassette  3  can be installed in and removed from a laser printer  1 . 
     Next,  FIG. 3  is a vertical cross sectional drawing that shows the internal configuration of the laser printer  1 . As shown in  FIG. 3 , a support plate  5  that has energy imparted to it in an upward direction by a spring  6  is provided in the interior of the paper feed cassette  3 , and a paper feed roller  9 , which feeds paper (not shown in the drawing) held in a stacked state on the support plate  5  toward the image forming part  7  separately one sheet at a time, is arranged further up on the front surface side of the support plate  5 . In addition, a conveyance roller  11 , which operates in conjunction with the paper feed roller  9  to convey the paper, and a guide  13 , which returns the paper conveyed by the conveyance roller  11  approximately 180° along the outer circumference of the paper feed roller  9 , and a pair of resist rollers  14  and  15 , which catch the front edge of the paper by appropriately stopping and adjusting the angular advance of the paper, are sequentially arranged in the conveyance path of the paper from the paper feed roller  9  to the image forming part  7 . 
     The image forming part  7  includes a photoconductor drum  21  as the image carrier body provided inside the photoconductor cartridge  20  and a transfer roller  22  opposing the photoconductor drum  21 . Note that the photoconductor drum  21  is a well-known type that forms an organic photoconductor (OPC) layer on the surface of a grounded metal core. 
     The paper, which passes between this photoconductor drum  21  and transfer roller  22  and on which an image resulting from toner is formed in the manner discussed below, is fed to a fixing part  31 . At the fixing part  31 , the toner image that is formed on the paper is held between a heating roller  33  and a transfer roller  35  and fixed by the heat, and the paper on which the image has been fixed is further conveyed by a pair of conveyance rollers  36  and  36 . 
     The paper, which has been conveyed by the conveyance rollers  36  and  36 , is guided above the cover  2  by a guide  37 , and is ejected to a paper eject tray  39  provided on the upper surface of the cover  2  by a pair of paper eject rollers  38  and  38 . In addition, a scanner unit  90 , which exposes the photoconductor drum  21  using laser light L, is arranged between the paper eject tray  39  and the photoconductor cartridge  20 . 
     Next, the configuration of the image forming part  7  and the scanner unit  90  will be explained in further detail. The photoconductor cartridge  20  as the image carrier body cartridge includes a photoconductor drum  21  so as to be rotatable and further includes a scorotron charging unit  23  that uniformly charges the surfaces of the transfer roller  22  and the photoconductor drum  21 . An electrostatic latent image is formed by laser light L incident from the scanner unit  90  via an exposure aperture part  20   a  on the surface of the photoconductor drum  21  charged by the scorotron charging unit  23 . Next, the electrostatic latent image is developed by a developing roller  41  provided on a developing cartridge  40  by supplying toner to the surface of the photoconductor drum  21 . This is because the toner that has adhered to the photoconductor drum  21  is transferred to the paper that has passed the aforementioned transfer roller  22 , and an image is formed on that paper by the above operation. 
     The developing roller  41  is rotatably supported by the developing cartridge  40  as shown in  FIG. 3  and comes into contact with the photoconductor drum  21  and is rotated and driven by a mechanism discussed below. The developing cartridge  40  includes an installation part  42  that supports a toner cartridge  60  so that it can be installed and removed and an aperture part  42   a , by which toner is supplied from the toner cartridge  60 , is bored into the installation part  42 . In addition, a lower auger  43 , which conveys the toner supplied from the aperture part  42   a  provided at the center portion in the shaft direction to both sides in the shaft direction, an upper auger  44 , which conveys the toner that has been conveyed by the lower auger  43  and has accumulated at both sides in the shaft direction to the center portion of the shaft direction and returns it to the toner cartridge  60  via the aperture part  42   a , a supply roller  45 , which feeds the toner conveyed by the lower auger  43  toward the developing roller  41 , and a developing blade  47 , which through friction charges the toner that has adhered to the surface of the developing roller  41  by the supply roller  45  and forms a thin layer of toner, are provided in the developing cartridge  40 . Also, an agitator  61  for agitating the accommodated toner and supplying it to the developing cartridge  40  side is provided in the interior of the toner cartridge  60 . 
     Next, the configuration of the scanner unit  90  will be explained. Scanner unit  90  includes a polygon mirror  91 , which deflects and scans the laser light L generated by a laser emission part that is not shown in the drawing, and mirrors  92 ,  93  that return the laser light L deflected by that polygon mirror  91  toward the photoconductor drum  21 . Also, an fθ lens  95  and a cylindrical lens  97  are respectively fixed in the optical path of the laser light L that has reached mirror  92  from the polygon mirror  91  and in the optical path of the laser light L that has reached mirror  93  from mirror  92 . 
     Through the above configuration, it is possible to form an electrostatic latent image on the surface of the photoconductor drum  21  by emitting laser light L at the appropriate timing while rotating the polygon mirror  91  and the photoconductor drum  21 . Then, in the aforementioned way, image formation by an electronic photographic system is possible by developing the electrostatic latent image using toner via a developing roller  41  and transferring it to paper. 
       FIG. 4  is a side view that shows the external appearance of the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60 . At the time of image formation, the operation part  62  of the toner cartridge  60  is arranged at the installation position shown in  FIG. 3  and  FIG. 4(A) , and in this state, the three parts, which are the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60 , are unified. For this reason, when the lid part  4  is opened and, also, the operation part  62  is pulled forward when the operation part  62  has been arranged at the installation position, the aforementioned three parts can be taken out as a unit from the installation and removal port  2   a  (see  FIG. 3 ) to outside the main body of the laser printer  1 . Note that the installation and removal port  2   a  is an aperture part of the cover  2  that is closed by the lid  4 . 
     When the operation part  62  of the toner cartridge  60  is rotated upward and arranged at the removal position shown in  FIG. 4(B) , the toner cartridge  60  is separated from a photoconductor cartridge  20  and a developing cartridge  40 , and when that operation part  62  is further pulled forward, it is possible to separate only the toner cartridge  60  as shown in  FIG. 4(B)  and take it out from the removal port  2   a  to outside the main body of the laser printer  1 . Through this, it is possible to replace the toner cartridge  60 . 
     In addition, a rotary shaft  41   a  (see  FIG. 5 ) of the developing roller  41  protrudes from the side surface of the developing cartridge  40 , and fits into a slot  20   b  that is bored into the photoconductor cartridge  20 . Due to this fitting, the developing cartridge  40  is movably linked to the photoconductor cartridge  20  along the line that joins the photoconductor drum  21  and the installation part  42 . In addition, when the operation part  62  is arranged at the installation position, the developing roller  41  is attached to the photoconductor drum  21  by applying a pressing force as explained below, and when the operation part  62  is arranged at the removal position, the pressing force is released. 
     Next, the configuration for installing and removing the toner cartridge  60  in this way will be explained. First, the configuration for switching between linkage and separation of the developing cartridge  40  and the toner cartridge  60  will be explained. 
       FIGS. 5(A)  and (B) show how the operation part  62  of the toner cartridge  60  has been arranged at the removal position, where  FIG. 5(A)  is a drawing of the installation part  42  of the developing cartridge  40  as seen from the toner cartridge  60  side, and  FIG. 5(B)  is a drawing of the toner cartridge  60  as seen from the installation part  42  side. 
     As shown in  FIG. 5(B) , the toner cartridge  60  includes a long cylindrical inner cylinder  63  whose interior accommodates the toner and an outer cylinder  64  that fits onto the outside of the center portion of that inner cylinder  63 . The outer cylinder  64  is installed on the installation part  42  so that it cannot be rotated by engaging a protruding stripe  64   a  that protrudes at the installation part  42  side with a long groove  42   b  formed on the inner wall surface of the installation part  42 . The inner cylinder  63  is such that the aforementioned operation part  62  is molded as a unit, and it is configured at the inner side of the outer cylinder  64  so that it is able to rotate according to the operation of the operation part  62 . 
     In addition, as shown in  FIG. 5(A) , a shutter  48  including a metal plate is arranged at the inside of the installation part  42 . The shutter  48  is arranged so that it is movable in the direction of the inner circumference of the installation part  42  between the position at which the aperture part  42   a  of the installation part  42  is closed and a position (refer to  FIG. 5(C) ) arranged to be shifted above the aperture part  42   a  as shown in  FIG. 5(A)  by supporting both ends by the rails  42   c  formed at the inner wall surface of the installation part  42 . 
     Four protrusions  63   a  which interpose the vicinity of both ends of the shutter  48  from both sides of the circumferential direction are formed on the surface of the inner cylinder  63 . For this reason, the shutter  48  moves according to the rotation of the inner cylinder  63 , and when the operation part  62  is arranged at the removal position, as shown in  FIG. 5(A) , the shutter  48  is arranged at a position that closes the aperture part  42   a . Note that the long groove  42   b  discussed above is formed further below that so that it does not stack with the shutter  48  arranged at this position. In addition, the aperture part  42   a  is formed in a lengthwise shape that is long in the horizontal direction, and a rectangular frame-shaped sponge  49  that surrounds the aperture part  42   a  is affixed at the inner wall surface of the installation part  42  in that vicinity. 
     An aperture part  64   b  of the same shape as aperture part  42   a  is formed at a portion of the outer cylinder  64  that opposes aperture part  42   a  when the protruding stripe  64   a  is engaged with the long groove  42   b , and a sponge  65  of the same shape as sponge  49  is affixed in the vicinity thereof. In addition, an aperture part  63   b  of the same shape as aperture part  64   b  is formed on the inner cylinder  63  as well, but when the operation part  62  is arranged at the removal position, aperture part  64   b  and aperture part  63   b  do not stack at all, as shown in  FIG. 5(B) . For this reason, the toner of the interior does not spill even when the toner cartridge  60  is removed. 
     In addition, after the protruding stripe  64   a  has engaged with the long groove  42   b , when the operation part  62  of the toner cartridge  60  is arranged at the installation position, aperture part  64   b  and aperture part  63   b  stack as shown in  FIG. 5(D) . In addition, at this time, as shown in  FIG. 5(C) , the shutter  48  is moved to above aperture part  42   a  by the protrusions  63   a , so both aperture part  64   b  and aperture part  42   a  communicate, and it becomes possible to supply the toner from the toner cartridge  60  to developing cartridge  40 . 
     Also, at this time, sponge  49  and sponge  65  closely adhere, and, moreover, the engagement parts  63   c  formed on the outer circumference surface of the inner cylinder  63  engage with the rails  42   c , so the vicinities of aperture parts  64   b  and  42   a  are tightly sealed, and toner is prevent from spilling out to the exterior. In addition, through this engagement of the engagement parts  63   c  and rails  42   c , the developing cartridge  40  and the toner cartridge  60  are linked. Conversely, by arranging the operation part  62  at the removal position and releasing the engagement of the engagement parts  63   c  and the rails  42   c , the direct linkage between the developing cartridge  40  and the toner cartridge  60  is released. 
     Also, a gear  901  that rotates in unison with the agitator  61  is arranged at the outer side of one end of the inner cylinder  63 , and a gear  902  for transmitting driving force to that gear  901  is exposed at a position that opposes the gear  901  of the installation part  42 . For this reason, by installing the toner cartridge  60  in the installation part  42  and engaging the engagement parts  63   c  with the rails  42   c  in the manner discussed above, it is possible to drive the agitator  61  via gears  902  and  901 . 
     Furthermore, the rotary shaft  903  of gear  901  protrudes to the left and right as shown in  FIGS. 5(B)  and (D), and a gear  905  is arranged at the other end of the rotary shaft  903 . A gear  906  for transmitting driving force to the lower auger  43  and the upper auger  44  is exposed at a position that opposes gear  905  of the installation part  42 . Note that the driving force transmission mechanisms of these will be discussed below. 
     As shown in  FIG. 4 , guide grooves  42   d  that guide this rotary shaft  903  are formed at the left and right end surfaces of the installation part  42 . The rotary shaft  903  is guided by the guide grooves  42   d  at the time of installation of the toner cartridge  60 , so it is easy to engage the protruding stripe  64   a  with the long groove  42   b.    
     Next,  FIG. 6(A)  is a drawing of the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60  as seen from the front surface side when the operation part  62  has been arranged at the aforementioned installation position, and  FIG. 6(B)  is a drawing of the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60  as seen from the front surface side when the operation part  62  has been arranged at the aforementioned removal position. 
     As shown in  FIGS. 6(A)  and (B), an aperture part  64   d  that passes through the operation part  62  so that rotation is possible in the aforementioned way is formed on the front surface side of the outer cylinder  64 . In addition, protruding parts  67  that are supported on the surface of the inner cylinder  63  by support parts  66  and that protrude in the left and right direction further than the installation part  42  are provided on both the left and right side surfaces of the operation part  62 . 
       FIG. 7(A)  is a side view that shows the configuration of the photoconductor cartridge  20 , and  FIG. 7(B)  is a partial view that shows the configuration of the front surface side end portion of the photoconductor cartridge  20  from the inner surface side. As shown in  FIG. 7(B) , concave spring parts  25  into which protruding parts  67  fit when the operation part  62  has been arranged at the installation position are arranged in the vicinity of the front surface side end part of the photoconductor cartridge  20 . The spring parts  25  are configured to be slidable centering on fulcrums  25   a  and impart energy in the direction of the photoconductor drum  21  through compression coil springs  26  in relation to receiving plates  20   c  molded as a unit at the front surface side of the photoconductor cartridge  20 . 
     For this reason, when the operation part  62  is rotated to the installation position, and the protruding parts  67  are fit into the spring parts  25 , as shown in  FIG. 8(A) , the developing cartridge  40  is pressed in the direction of the photoconductor drum  21  via the toner cartridge  60 , and the developing roller  41  is pressure attached to the photoconductor drum  21 . In addition, at this time, the shutter  48  is opened, engagement parts  63   c  and rails  42   c  engage, and aperture parts  42   a ,  63   b , and  64   b  communicate, so it is possible to perform image formation in the aforementioned way. 
     Conversely, when the operation part  62  is rotated to the removal position, and the fitting of the protruding parts  67  and the spring parts  25  is undone, as shown in  FIG. 8(B) , the aforementioned pressing is released. In addition, at this time, the shutter  48  is closed, the engagement of engagement parts  63   c  and rails  42   c  is released, and aperture parts  63   b  and  64   b  are arranged to be mutually unaligned, so it is possible to remove the toner cartridge  60  without spilling toner. Note that, as shown in  FIG. 6 , the receiving plates  20   c  and the spring parts  25  are arranged at the outer side in the left and right directions of the toner cartridge  60  and the installation part  42 , so these do not become and obstruction at the time of installation and removal of the toner cartridge  60 . Also, as shown in  FIG. 2  and  FIG. 3 , and interference member  4   c  is provided in a protruding manner at the inner surface of the lid part  4 , and the configuration is such that, if the operation part  62  is not arranged at the installation position, that operation part  62  and interference member  4   c  interfere with each other, and it is not possible to close the lid part  4 . 
     Next, the mechanism for transmitting driving force to the developing roller  41 , etc. will be explained. Returning to  FIG. 7(A) , a metal rotary shaft  21   a  of the photoconductor drum  21  protrudes from the photoconductor cartridge  20  at both the left and right sides, and a gear  21   b  that rotates in unison with the photoconductor drum  21  is exposed from the end portion of the rear side (installation direction side) of the photoconductor cartridge  20 . 
     In contrast with this, as shown in  FIG. 9 , a guide groove  121  that guides the rotary shaft  21   a  is formed on the inner wall surface of the left side of the main body of the laser printer  1 , and a gear  121   b  that meshes with gear  21   b  is provided. By this gear  21   b  and gear  121   b  meshing with each other at the time of installation of the photoconductor drum  20 , driving force can be transmitted from the main body side to the photoconductor drum  21 . 
     To continue,  FIG. 10(A)  is a left side surface view that shows the configuration of the developing cartridge  40  and the toner cartridge  60 , and  FIG. 10(B)  is a right side surface view that shows the configuration of the developing cartridge  40  and the toner cartridge  60 . As shown in  FIG. 10(A) , a drive shaft  51  through which driving force is transmitted from the drive shaft  151  (see  FIG. 9 ) of the main body side is provided at the left side surface of the developing cartridge  40 . Note that, in addition to drive shaft  151 , at the end face, comprising a flat protruding part  151   a  and drive shaft  51  being formed into a cylindrical concave part into which drive shaft  151  can fit, a protrusion  51   a  that is able to engage with flat protruding part  151   a  is formed, and a so-called drive coupling is formed by the two. 
     As shown in  FIG. 10(A) , a gear  51   b  that rotates in unison is formed on drive shaft  51 , and this gear  51   b  meshes with a gear  41   b  that rotates in unison with the developing roller  41 , a gear  45   a  that rotates in unison with the supply roller  45 , and gear  902  discussed above. In addition, gear  901 , which rotates in unison with rotary shaft  903  of the agitator  61  meshes with gear  902  at the time of installation of the toner cartridge  60  in the aforementioned way, and, in the same way, driving force is transmitted to a gear  906  via a gear  905  that rotates in unison with rotary shaft  903 . 
     As shown in  FIG. 10(B) , gear  906  meshes with gears  43   a  and  44   a , which respectively rotate in unison with the lower auger  43  and the upper auger  44 . For this reason, driving force is transmitted from drive shaft  151  to drive shaft  51 , and, through that driving force, it is possible to rotate the developing roller  41 , the supply roller  45 , the agitator  61 , the lower auger  43 , and the upper auger  44 . 
     In a laser printer  1  configured in the above way, if the toner cartridge  60  is caused to be removed from the installation part  42  at the time of shipping, it is possible to maintain a state in which the pressure attachment of the photoconductor drum  21  and the developing roller  41  has been released as shown in  FIG. 8(B) . For this reason, it is possible to prevent chemical damage to the photoconductor drum  21  and permanent deformation of the developing roller  41 . 
     Also, as shown in  FIG. 8(A) , it is possible to pressure attach the developing roller  41  to the photoconductor drum  21  merely by installing the toner cartridge  60  in the installation part  42 , so operability at the time of the start of usage is improved. Furthermore, the pressure attachment is released again when the toner cartridge  60  is removed from the installation part  42  and replaced, so it is possible to better prevent chemical damage to the photoconductor drum  21  and permanent deformation of the developing roller  41 . Moreover, at this time, the rotary shaft  41   a  of the developing roller  41  is guided by a slot  20   b , so it is possible to perform the pressure attachment and pressure attachment release even more smoothly, and the positional relationship between the photoconductor drum  21  and the developing roller  41  also becomes difficult to move. 
     In addition, if the toner cartridge  60  is installed in the installation part  42 , in the manner discussed above, the photoconductor drum  20 , the developing cartridge  40 , and the toner cartridge  60  are made into a unit, and it is possible to perform installation and removal as a unit along the guide groove  121 . Therefore, in the laser printer  1 , the ability to resolve jam handling can be improved. Also, by the protruding parts  67  fitting into the spring parts  25  and pressing the toner cartridge  60  in the direction of the developing cartridge  40 , a state in which the photoconductor drum  20 , the developing cartridge  40 , and the toner cartridge  60  are joined is maintained at least two locations, making it possible to reinforce the strength of the rails  42   c  and the engagement parts  63   c.    
     Note that, in the above illustrative aspect, the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60  can correspond to a process cartridge, the photoconductor cartridge  20  and the developing cartridge  40  can correspond to the main body cartridge, the housing portion of the photoconductor cartridge  20  and the developing cartridge  40  can correspond to the housing, protruding parts  67 , spring parts  25 , and compression coil springs  26  or like can correspond to the pressure attachment device, rails  42   c  and engagement parts  63   c  can correspond to the engagement parts, protruding parts  67  and the fitting parts can correspond to the action receiving parts, spring parts  25  can correspond to the fitting receiving parts, and shutter  48  and outer cylinder  64  can correspond to the shielding member. 
     Also, aspects of the present invention are not limited in any way to the above described aspects, and it is possible to implement various modes within a scope that comports with aspects of the present invention. For example, as shown in  FIG. 11 , the slot  20   b  may be opened on the toner cartridge  60  side. In this case, from the state shown in  FIG. 11(A) , when the toner cartridge  60  is removed as shown in  FIG. 11(B)  in the same way as in the above aspect, as shown in  FIG. 11(C) , it is possible to easily separate the developing cartridge  40  from the photoconductor cartridge  20 . Therefore, it is possible to respectively individually replace the photoconductor cartridge  20 , the developing cartridge  40 , and the toner cartridge  60  according to the lifespan of the photoconductor drum  21  and the developing roller  41 , etc. 
     In addition, an elastic member that generates a pressing force for attaching the developing roller  41  to the photoconductor drum  21  may be provided on the toner cartridge  60  side.  FIG. 12(A)  is a side surface view that shows the configuration of the toner cartridge  60  according to this aspect. As shown in  FIG. 12(A)  and in  FIG. 12(B)  as a partial enlarged drawing thereof, in addition to holes  62   a  being bored in the vicinity of protruding parts  67  of the operation part  62 , protruding parts  67  are formed by a single shaft that passes through the holes  62   a . In addition, the support parts  66  of protruding parts  67  are formed by elastic members such as rubber, and the protruding parts  67  are made displaceable within the holes  62   a  shown in  FIG. 12(C)  by elastic deformation of the support parts  66 . 
     In this case, there is no need to provide spring parts  25  in the photoconductor cartridge  20 , and, as shown in  FIG. 13 , concave fitting receiving parts  20   d  into which the protruding parts  67  fit may be provided. According to this aspect, when the operation part  62  is arranged at the installation position, and the protruding parts  67  are fit into the fitting receiving parts  20   d  as shown in  FIG. 13(A) , it is possible apply a pressing force to attach a developing roller  41  to a photoconductor drum  21  by the imparted energy applied from the support parts  66 . When the operation part  62  is arranged at the removal position as shown in  FIG. 13(B) , the aforementioned fitting is undone, and it is possible to release the aforementioned pressure attachment, and, in that state, it is possible to remove the toner cartridge  60  as shown in  FIG. 13(C) . Note that, according to this aspect, the support parts  66  may be configured by coil springs or plate springs other than rubber ones. Furthermore, the attachment may be performed by fitting resin protruding parts and fitting receiving parts with each other without using elastic members. 
     Furthermore, aspects of the present invention can also be applied to image forming apparatuses of the type in which the toner cartridge is installed and removed from the side of the developing cartridge. In this case as well, if the configuration is such that the toner cartridge is replaced once the entire process cartridge is removed, by using an appropriate link mechanism, etc., it is possible to link the installation and removal of the toner cartridge with the aforementioned pressure attachment/pressure attachment release. However in the above respective aspects, it is possible to individually replace the toner cartridge  60  from the front side of the laser printer  1 , which can result in improved maintenance. 
     In addition, the pressure attachment device may be provided on the image forming apparatus main body.  FIG. 14  is a vertical cross sectional view that shows the configuration according to this aspect. As shown in  FIG. 14 , a pressing member  102  as the pressure attachment device is arranged on a support plate  101  that supports the photoconductor cartridge  20  in the main body of the laser printer  1 . This pressing member  102  is provided so that it is able to slide in the forward and back directions by way of a guide  101   a  integrated with the support part  101 . The pressing member  102  also imparts energy toward the back by a coil spring  103 . In addition, the pressing member  102  includes a groove part  102   a  that engages with the operation part  62  when that operation part  62  is arranged at the installation position. 
     For this reason, when the toner cartridge  60  is installed on the installation part  42 , and the operation part  62  is rotated to the operation position, the operation part  62  engages with the groove part  102   a , and the imparted energy of the coil spring  103  is transmitted to the developing roller  41  by the toner cartridge  60 . On the other hand, at the time of replacement of the toner cartridge  60 , the operation part  62  is rotated to the removal position while pulling the pressing member  102  to the front. When this is done, the aforementioned imparted energy is transmitted to the developing roller  41 , and it also becomes possible to remove the toner cartridge  60 . Therefore, according this aspect, the same action and effects as in the aforementioned respective aspects are produced. 
     While the invention has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.