Abstract:
An image forming apparatus includes: a main casing; a belt unit having a belt and a belt cleaning unit; a waste toner container; and a supporting member supporting the waste toner container and a cartridge storing toner supplied to a photosensitive member. The supporting member in the main casing is movable between a contact position where the photosensitive member contacts the belt and a separation position where the photosensitive member separates from the belt. One of the waste toner container and the belt cleaning unit is movable between a connected position providing connection to each other and a disconnected position providing disconnection from each other when the support member is in the contact position. The supporting member moves between the contact position and the separation position when one of the waste toner container and the belt cleaning unit is in the disconnected position.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from Japanese Patent Application No. 2012-285968 filed Dec. 27, 2012. The entire content of the priority application is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to an electro-photographic image forming apparatus that detachably accommodates a plurality of process cartridges therein. 
       BACKGROUND 
       [0003]    Image forming devices that detachably accommodate a plurality of process cartridges are well-known in the art. 
         [0004]    One of such printers includes a main body and an image forming unit detachably mountable in the main body. The image forming unit supports a plurality of process cartridges (for example, see Japanese Patent Application Publication No. 2010-008472). 
         [0005]    In this printer, the image forming unit includes a waste toner box to store waste toner, and the main body includes a belt waste-toner conveying tube. The belt waste-toner conveying tube is configured to convey waste toner collected by a belt cleaning device to the waste toner box. 
       SUMMARY 
       [0006]    In the above-described printer, the belt waste-toner conveying tube is fixed to the main body. On the other hand, the image forming unit, which includes the waste toner box, is configured to move relative to the main body. Specifically, the image forming unit is moved horizontally and then diagonally downward along an inclined portion to be positioned and accommodated in the main body. When accommodated in the main body, the waste toner box and the belt waste-toner conveying tube are connected to each other. 
         [0007]    However, for accommodating the image forming unit in the main body, positioning of the image forming unit is performed while the image forming unit moves relative to the main body. Conceivably, under this construction, the waste toner box and the belt waste-toner conveying tube may be not connected to each other as intended. As a result, the waste toner collected by the belt cleaning device cannot be stored in the waste toner box. 
         [0008]    In view of the foregoing, it is an object of the present invention to provide an image forming device which can ensure connection of a waste toner container and a belt cleaning unit. 
         [0009]    In order to attain the above and other objects, there is provided an image forming apparatus configured to form a toner image on a photosensitive member. The image forming apparatus includes: a main casing; a belt unit having a belt and a belt cleaning unit configured to collect waste toner adhered to the belt; a waste toner container configured to store the waste toner collected by the belt cleaning unit; and a supporting member configured to support the waste toner container and a cartridge that stores toner to be supplied to the photosensitive member. The supporting member is configured to move between an internal position where the supporting member is inside the main casing and an external position where the supporting member is at least partly outside the main casing. The supporting member in the internal position is further configured to move between a contact position where the photosensitive member is in contact with the belt and a separation position where the photosensitive member is separated from the belt. One of the waste toner container and the belt cleaning unit is configured to move between a connected position providing connection between the waste toner container and the belt cleaning unit and a disconnected position providing disconnection between the waste toner container and the belt cleaning unit when the support member is in the contact position. The supporting member is configured to move between the contact position and the separation position when one of the waste toner container and the belt cleaning unit is in the disconnected position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    In the drawings: 
           [0011]      FIG. 1  is a central cross-sectional view of a printer as an example of an image forming apparatus according to a first embodiment of the present invention, the printer accommodating a process unit that includes a waste toner cartridge; 
           [0012]      FIG. 2  is a view for explaining mounting and dismounting of the waste toner cartridge according to the first embodiment, wherein a front cover is in an open position, the waste toner cartridge is in a connected position, and the process unit is in a contact position; 
           [0013]      FIG. 3  is a view for explaining mounting and dismounting of the waste toner cartridge according to the first embodiment, wherein the front cover is in the open position, the waste toner cartridge is in a disconnected position, and the process unit is in the contact position; 
           [0014]      FIG. 4  is a view for explaining mounting and dismounting of the waste toner cartridge according to the first embodiment, wherein the front cover is in the open position, the waste toner cartridge is in the disconnected position, and the process unit is in a separation position; 
           [0015]      FIG. 5  is a view for explaining mounting and dismounting of the waste toner cartridge according to the first embodiment, wherein the front cover is in the open position, the waste toner cartridge is in a disconnected position, and the process unit is in an external position; 
           [0016]      FIG. 6  is a central cross-sectional view of a printer as an example of an image forming apparatus according to a second embodiment of the present invention, the printer accommodating the process unit that includes a waste toner cartridge according to the second embodiment; 
           [0017]      FIG. 7  is a view for explaining mounting and dismounting of the waste toner cartridge according to the second embodiment, wherein the front cover is in the open position, the waste toner cartridge is in a connected position, and the process unit is in the contact position; 
           [0018]      FIG. 8  is a view for explaining mounting and dismounting of the waste toner cartridge according to the second embodiment, wherein the front cover is in the open position, the waste toner cartridge is in a disconnected position, and the process unit is in the contact position; 
           [0019]      FIG. 9  is a view for explaining mounting and dismounting of the waste toner cartridge according to the second embodiment, wherein the front cover is in the open position, the waste toner cartridge is in the disconnected position, and the process unit is in the separation position; and 
           [0020]      FIG. 10  is a view for explaining mounting and dismounting of the waste toner cartridge according to the second embodiment, wherein the front cover is in the open position, the waste toner cartridge is in the disconnected position, and the process unit is in the external position. 
       
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       [0021]    A printer  1  as an example of an image forming apparatus according to a first embodiment of the present invention will be described with reference to  FIGS. 1 through 5 . 
       1. Overall Structure of the Printer 
       [0022]    In the following description, directions related to the printer  1  will be given assuming that the printer  1  is resting on a horizontal flat surface. More specifically, the left side of the printer  1  in  FIG. 1  will be considered the “front side”, and the right side of the printer  1  in  FIG. 1  will be considered the “rear side”. Further, the near side in  FIG. 1  will be considered the “right side”, and the far side in  FIG. 1  will be considered the “left side”. A vertical direction in  FIG. 1  will be referred to as an “up-down direction” with regard to the printer  1 . 
         [0023]    The printer  1  is a horizontal intermediate transfer type color printer. As shown in  FIG. 1 , the printer  1  includes a main casing  2  within which a sheet feeding unit  3  and image forming unit  4  are disposed. The sheet feeding unit  3  is configured to feed sheets P of paper. The image forming unit  4  is configured to form images on the sheets P fed from the sheet feeding unit  3 . 
         [0024]    (1) Main Casing 
         [0025]    The main casing  2  is formed in a substantially rectangular box-like shape in a side view. The main casing  2  accommodates the sheet feeding unit  3  and the image forming unit  4 . The main casing  2  has a front wall in which a main body aperture  6  is formed. A front cover  7  is pivotally movably provided on the front wall for covering and exposing the main body aperture  6 . Specifically, the front cover  7  is pivotably movable about its lower end portion between a closed position shown in  FIG. 1  for closing the main body aperture  6 , and an open position shown in  FIGS. 2 through 5  for opening the main body aperture  6 . 
         [0026]    (2) Sheet Feeding Unit 
         [0027]    As show in  FIG. 1 , the sheet feeding unit  3  includes a sheet tray  10  which accommodates the sheets P of paper. The sheets P in the sheet tray  10  are conveyed between a sheet feed roller  14  and a sheet feed pad  15  by rotation of a pickup roller  13 , and are separated into individual sheets P by the rotation of the sheet feed roller  14 . Each sheet P thus separated then passes between pinch rollers  16  and is fed upward toward between a pair of registration rollers  17  by the rotation of the sheet feed roller  14 . As the registration rollers  17  rotate, the sheet P is fed between an intermediate transfer belt  41  (described later) and a secondary transfer roller  38  (described later) provided in the image forming unit  4  with a prescribed timing. 
         [0028]    (3) Image Forming Unit 
         [0029]    The image forming unit  4  is disposed upward of the sheet feeding unit  3 , and includes a scanner unit  22 , a process unit  23 , a transfer unit  24 , and a fixing unit  25 . 
         [0030]    (3-1) Scanner Unit 
         [0031]    The scanner unit  22  is disposed in a lower portion of the main casing  2 , upward of the paper feed tray  10 . The scanner unit  22  emits laser beams toward respective photosensitive drums  28  (described later), path of which are depicted by solid lines in  FIG. 1 , based on image data. The photosensitive drums  28  are thus exposed to light by the laser beams through exposure holes  80  formed on a process frame  27  (described later). 
         [0032]    (3-2) Process Unit 
         [0033]    The process unit  23  is disposed substantially in a center of the main casing  2  in the up-down (vertical) direction, upward of the scanner unit  22 . When accommodated in the main casing  2  as shown in  FIG. 1 , the process unit  23  is positioned frontward of the registration rollers  17 . More specifically, when accommodated in the main casing  2  (to be referred to as an “internal position” hereinafter), the process unit  23  is further configured to move in the up-down direction between a contact position (shown in  FIGS. 1 to 3 ) and a separation position (shown in  FIG. 4 ). When the process unit  23  is in the contact position, the photosensitive drums  28  are in contact with the intermediate transfer belt  41 . In the separation position, the photosensitive drums  28  are separated from the intermediate transfer belt  41 . Moreover, the process unit  23  is movable in a front-rear direction between the separation position and an external position shown in  FIG. 5 . In the external position, the process unit  23  is withdrawn from the main casing  2 . That is, the process unit  23  is movable between the contact position and the separation position in the up-down direction when at the internal position, and the process unit  23  is further movable between the separation position and the external position in the front-rear direction. 
         [0034]    The process unit  23  includes four process cartridges  26  corresponding to respective colors, and the process frame  27 . 
         [0035]    The process cartridges  26  are juxtaposedly arrayed and spaced away from one another in the front-rear direction (a pull-out direction). Each of the process cartridges  26  integrally holds the corresponding photosensitive drum  28 , a Scorotron charger  29 , and a developing device  30 . 
         [0036]    The photosensitive drums  28  are formed in a substantially cylindrical shape extending in a left-right direction. 
         [0037]    The Scorotron charger  29  is disposed diagonally downward and rearward of the corresponding photosensitive drum  28  so as to oppose the same with a distance therebetween. 
         [0038]    The developing device  30  is disposed downward and frontward of the corresponding photosensitive drum  28 . Each developing device  30  includes a developing device frame  98  and a developing roller  31 . 
         [0039]    The developing roller  31  is rotatably supported to an upper end portion of the developing device frame  98 . The developing roller  31  is exposed from the upper end portion of the developing device frame  98  to contact the corresponding photosensitive drum  28  from a lower front side thereof. 
         [0040]    Each developing device  30  also includes a supply roller  32 , a thickness regulating blade  33 , and a toner accommodating chamber  34 . The supply roller  32  is configured to supply toner to the corresponding developing roller  31 . The thickness regulating blade  33  serves to regulate a thickness of the toner supplied to the developing roller  31 . The toner accommodating chamber  34  is formed in the 98 rearward and downward of the supply roller  32  and severs to accommodate toner therein. 
         [0041]    The process frame  27  detachably holds the four process cartridges  26 . The process frame  27  is movable in the up-down direction within the main casing  2 . Further, the process frame  27  is also configured to slide in the front-rear direction such that the process frame  27  can be accommodated in and withdrawn from the main casing  2 . 
         [0042]    (3-3) Transfer Unit 
         [0043]    The transfer unit  24  is disposed in an upper portion of the main casing  2 , upward of the process unit  23 . The transfer unit  24  includes a belt unit  37  and the secondary transfer roller  38 . 
         [0044]    The belt unit  37  extends in the front-rear direction and is disposed upward of the process unit  23  in the contact position to oppose the photosensitive drums  28  from above. The belt unit  37  includes a driving roller  39 , a following roller  40 , the intermediate transfer belt  41 , and four primary transfer rollers  42 . 
         [0045]    The driving roller  39  and the following roller  40  are disposed to oppose each other and are separated from each other in the front-rear direction. Specifically, the following roller  40  is disposed on a front end portion of the belt unit  37 , and the driving roller  39  is disposed on a rear end portion of the belt unit  37 . 
         [0046]    The intermediate transfer belt  41  is mounted on and around the driving roller  39  and the following roller  40  in a taut state. The intermediate transfer belt  41  has a lower portion that can contact each of the photosensitive drums  28 . As the driving roller  39  rotates, the lower portion of the intermediate transfer belt  41  is circularly moved rearward, and the following roller  40  is caused to rotate along with the circular movement of the intermediate transfer belt  41 . 
         [0047]    Each of the four primary transfer rollers  42  is provided to oppose the corresponding one of the photosensitive drums  28  with the lower portion of the intermediate transfer belt  41  interposed therebetween. 
         [0048]    The secondary transfer roller  38  is provided rearward of the belt unit  37  such that the secondary transfer roller  38  opposes the driving roller  39  with the intermediate transfer belt  41  nipped therebetween. 
         [0049]    (3-4) Fixing Unit 
         [0050]    The fixing unit  25  is disposed upward of the secondary transfer roller  38 . The fixing unit  25  includes a heating roller  43  and a pressure roller  44  opposing the heating roller  43 . 
         [0051]    (4) Image Forming Operation 
         [0052]    The toner in the toner accommodating chamber  34  of each developing device  30  is supplied to the corresponding supply roller  32 , and the supply roller  32  in turn supplies the toner to the corresponding developing roller  31 . 
         [0053]    The toner supplied onto the developing roller  31  is tribocharged to a positive polarity between the supply roller  32  and the developing roller  31 , as the developing roller  31  rotates. The thickness regulating blade  33  regulates a thickness of the toner carried on the developing roller  31 , thereby maintaining the toner on the surface of the developing roller  31  at a thin layer with a uniform thickness. 
         [0054]    Meanwhile, the Scorotron charger  29  applies a uniform charge to a surface of the corresponding photosensitive drum  28 , as the photosensitive drum  28  rotates. Subsequently, the scanner unit  22  exposes the surface of the photosensitive drum  28  based on prescribed image data, thereby forming an electrostatic latent image on the surface of each photosensitive drum  28 . The toner carried on each developing roller  31  is then supplied to the electrostatic latent image formed on the surface of the corresponding photosensitive drum  28 , thereby a toner image being carried on the surface of the photosensitive drum  28 . 
         [0055]    The toner images carried on the surfaces of the photosensitive drums  28  are then sequentially transferred onto the lower portion of the intermediate transfer belt  41  that moves rearward while the intermediate transfer belt  41  circularly moves (primary transfer). A color image is thus formed on the lower portion of the intermediate transfer belt  41 . 
         [0056]    The color image formed on the intermediate transfer belt  41  is subsequently transferred onto the sheet P fed from the sheet feeding unit  3 , as the sheet P passes between the intermediate transfer belt  41  and the secondary transfer roller  38  (secondary transfer). 
         [0057]    The color image which has been transferred onto the sheet P is then thermally fixed thereon by heat and pressure while the sheet P passes between the heating roller  43  and the pressure roller  44 . 
         [0058]    (5) Sheet Discharge 
         [0059]    The main casing  2  has an upper surface in which a discharge tray  47  is formed for receiving the image-formed sheet P. The main casing  2  has an upper-rear end portion from which a discharge unit  48  protrudes upward. The discharge unit  48  protrudes further upward than the discharge tray  47  in the up-down direction. 
         [0060]    The discharge unit  48  includes a discharge outlet  49  through which the sheet P is discharged. The discharge outlet  49  is positioned higher than the discharge tray  47  in the up-down direction. The discharge unit  48  also includes two discharge rollers  50  adjacent to the discharge outlet  49  for discharging the sheet P to the discharge tray  47  through the discharge outlet  49 . 
         [0061]    The discharge rollers  50  rotate to convey the image-formed sheet P toward outside of the main casing  2  through the discharge outlet  49  to be finally received in the discharge tray  47 . 
       2. Detailed Structure of the Belt Unit 
       [0062]    The belt unit  37  includes a belt cleaning unit  55 . 
         [0063]    The belt cleaning unit  55  is provided on the front end portion of the belt unit  37 . The belt cleaning unit  55  includes a belt cleaner  56  and a belt-side connecting part  57 . 
         [0064]    The belt cleaner  56  includes a belt cleaner frame  60 , a blade member  61 , and a belt-side auger  62 . 
         [0065]    The belt cleaner frame  60  is formed in a substantially box-like shape. As shown in  FIG. 1 , the belt cleaner frame  60  is disposed to confront the following roller  40  from above in an inclined state in a side view. Specifically, the belt cleaner frame  60  slopes diagonally frontward and downward from the front end portion of the belt cleaning unit  55 . The belt cleaner frame  60  integrally includes an auger accommodating part  63  and a blade mounting part  64 . 
         [0066]    The auger accommodating part  63  occupies a rearward portion of the belt cleaner frame  60 , the rearward portion constituting substantially one-third of the belt cleaner frame  60  in the front-rear direction. The auger accommodating part  63  is formed in a partial cylindrical shape extending in the left-right direction. The auger accommodating part  63  has a right end portion that is closed, and a left end portion that is in communication with the belt-side connecting part  57  as will be described later. The auger accommodating part  63  has a lower end portion that is open generally downward to oppose the following roller  40 . 
         [0067]    The blade mounting part  64  is formed frontward of the auger accommodating part  63  and constitutes substantially two-thirds of the belt cleaner frame  60  in the front-rear direction. The blade mounting part  64  is formed in a partial rectangular tube-like shape extending in the left-right direction, with both left and right end portions closed. The blade mounting part  64  has a rear lower portion that is open generally downward. 
         [0068]    The blade member  61  is disposed on a rear end portion of the blade mounting part  64 . The blade member  61  formed in a substantially plate-like shape extending in the left-right direction and has a thickness in the front-rear direction. The blade member  61  has a front end portion that is fixed to the rear end portion of the blade mounting part  64 . The blade member  61  has a rear end portion (distal end portion) that is exposed from the blade mounting part  64 . The rear end portion of the blade member  61  extends beneath the auger accommodating part  63  to confront the open lower end portion of the auger accommodating part  63 . The rear end portion of the blade member  61  contacts the intermediate transfer belt  41  provided on a circumferential surface of the following roller  40  from upward and frontward thereof. 
         [0069]    The belt-side auger  62  is an auger screw extending in the left-right direction. The belt-side auger  62  is disposed within the auger accommodation part  63 . The belt-side auger  62  has a left end portion that is disposed within the belt-side connecting part  57  (described later). 
         [0070]    The belt-side connecting part  57  is formed in a substantially cylindrical shape. The belt-side connecting part  57  extends leftward from the left end portion of the auger accommodation part  63 , then bends downward and frontward, and then extends downward. In other words, the belt-side connecting part  57  is provided leftward (outward) of the left end portion of the auger accommodation part  63  in the left-right direction. The belt-side connecting part  57  has a lower end portion in which a belt-side communication port  68  is defined. The belt-side communication port  68  is substantially circular in bottom view. Interior and exterior of the belt cleaning unit  55  are in communication with each other through the belt-side communication port  68 . The belt-side connecting part  57  includes a belt-side shutter  69 . 
         [0071]    The belt-side shutter  69  is formed in a substantially flat plate-like shape. The belt-side shutter  69  is slidably movable between an open position (shown in  FIGS. 1 and 2 ) opening the belt-side communication port  68  and a closed position (shown in  FIGS. 3 through 5 ) closing the closes the belt-side communication port  68 . The belt-side shutter  69  is constantly biased toward the closed position by a biasing spring (not shown). 
       3. Detailed Structure of the Process Unit 
       [0072]    The process unit  23  includes the process frame  27  and the four process cartridges  26 . In addition, the process unit  23  includes a waste toner cartridge  101 . 
         [0073]    (1) Process Frame 
         [0074]    The process frame  27  is formed in a substantially rectangular frame-like shape with a closed bottom in a plan view, as shown in  FIG. 1 . The process frame  27  includes a pair of side walls (not shown), a front wall  73 , a rear wall  74 , and a bottom wall  75 . 
         [0075]    The pair of side walls (not shown) is formed in a substantially rectangular plate-like shape in a side view, extending in the front-rear direction. The side walls are disposed in opposition to and in separation from each other in the left-right direction. 
         [0076]    The front wall  73  is formed in a substantially plate-like shape extending in the left-right direction. The front wall  73  is disposed to connect front end portions of the side walls. The front wall  73  has a front surface on which a grip part  76  is provided for a user to grasp the same. As shown in  FIG. 2 , the front wall  73  has a left and right end portions to which a front guide roller  77  is rotatably supported. The front guide roller  77  is formed in a substantially cylindrical shape extending in the left-right direction. 
         [0077]    The front guide roller  77  is positioned lower than the belt-side connecting part  57  in the up-down direction the when the process unit  23  is accommodated in the main casing  2 . 
         [0078]    The rear wall  74  is formed in a substantially plate-like shape extending in the left-right direction and has a thickness in the front-rear direction. The rear wall  74  is disposed to bridge rear end portions of the not shown side walls. The rear wall  74  has left and right end portions to which a rear guide roller  78  is rotatably supported. The rear guide roller  78  is formed in a substantially cylindrical shape extending in the left-right direction. 
         [0079]    The rear guide roller  78  is positioned lower than the belt-side connecting part  57  in the up-down direction when the process unit  23  is accommodated in the main casing  2 . 
         [0080]    The bottom wall  75  connects between lower end portions of the front wall  73  and the rear wall  74 , and between lower end portions of the side walls (not shown) of the process frame  27 . The bottom wall  75  is formed in a substantially rectangular shape in a plan view. The bottom wall  75  is formed with four partitioning walls  79  and the four exposure holes  80 . 
         [0081]    The four exposure holes  80  are aligned and spaced away from each other in the front-rear direction. Each of the exposure holes  80  has a substantially rectangular shape extending in the left-right direction in a plan view and penetrates through the bottom wall  75  in the up-down direction. up-down direction 
         [0082]    The four partitioning walls  79  are formed frontward of and separated from the respective four exposure holes  80 . The partitioning walls  79  have a substantially right triangular shape in a side view. More specifically, each partitioning wall  79  protrudes upward from an upper surface of the bottom wall  75  and has a front surface extending in the up-down direction. Each partitioning wall  79  has left and right ends connected to the not illustrated side walls of the process frame  27 . 
         [0083]    In the process frame  27 , four process cartridge accommodating sections  83  are defined by the four partitioning walls  79 , the rear wall  74  and the side walls (not shown). Specifically, three spaces enclosed by the neighboring partitioning walls  79  and the side walls, and a space enclosed by the rearmost partitioning wall  79 , the rear wall  74  and the side walls are defined as the process cartridge accommodating sections  83  for receiving the process cartridges  26 . 
         [0084]    Further, a space enclosed by the frontmost partitioning wall  79 , the front wall  73 , and the side walls of the process frame  27  is defined as a waste toner cartridge accommodating section  84  for receiving the waste toner cartridge  101 . 
         [0085]    Each process cartridge  26  is detachably accommodated in the corresponding process cartridge accommodating section  83 . Each process cartridge  26  includes a drum unit  88  and the developing device  30 . 
         [0086]    Each drum unit  88  includes a drum frame  89 . 
         [0087]    Each drum frame  89  is formed in a substantially box-like shape whose top and bottom sides are open. Each drum frame  89  has side walls (left and right side walls) to which the corresponding photosensitive drum  28  is rotatably supported. The photosensitive drum  28  has top and bottom end portions exposed from the drum frame  89 . Each drum frame  89  has a rear wall in which the corresponding Scorotron charger  29  is embedded. Each drum frame  89  includes a pair of drum-side engaging parts  91 . 
         [0088]    The drum-side engaging parts  91  are provided each on a lower end portion of each side wall of the corresponding drum frame  89 . Each drum-side engaging part  91  has a substantially right triangular plate-like shape in a side view, extending frontward from the lower end portion of each side wall of the drum frame  89 . 
         [0089]    Each developing device  30  includes the developing device frame  98 . 
         [0090]    The developing device frame  98  is formed in a substantially box-like shape which is open diagonally upward and rearward. The developing device frame  98  has a pair of side walls to which the developing roller  31  and supply roller  32  are rotatably supported. The developing device frame  98  has a lower rear portion in which the toner accommodating chamber  34  is formed. The developing device frame  98  also includes a pair of developing-side engaging parts  99 . 
         [0091]    The developing-side engaging parts  99  are formed each on a lower end portion of each side wall of the developing device frame  98 . The developing-side engaging parts  99  are in a substantially semicircular shape in a side view, extending rearward respectively from the lower end portions of the side walls of the developing device frame  98 . 
         [0092]    The developing-side engaging parts  99  and the drum-side engaging parts  91  are engaged with each other such that the developing roller  31  and the photosensitive drum  28  are in contact with each other. The developing device  30  and the drum unit  88  thus engaged with each other constitute the process cartridge  26 . Further, the developing device  30  and the drum unit  88  are pivotably movable relative to each other about the developing-side engaging parts  99  and the drum-side engaging parts  91 . Hence, when the process cartridge  26  is removed from the main casing  2 , the developing roller  31  and the photosensitive drum  28  can contact and separate from each other. 
         [0093]    In the process cartridge  26 , the developing-side engaging parts  99  and the drum-side engaging parts  91  are engaged at positions outward of the photosensitive drum  28  in the left-right direction. The bottom end portion of the photosensitive drum  28  is thus exposed downward from the drum frame  89 . Therefore, the laser beams from the scanner unit  22  can pass through the exposure holes  80  formed on the bottom wall  75  of the process frame  27  to expose the surfaces of the corresponding photosensitive drums  28  to light. 
         [0094]    The waste toner cartridge  101  is detachably accommodated in the waste toner cartridge accommodating section  84 . In other words, the waste toner cartridge  101  is disposed frontward of the frontmost process cartridge  26  in the process unit  23 . The waste toner cartridge  101  includes a waste toner accommodating part  102  and an accommodating-side connecting part  103 . 
         [0095]    The waste toner accommodating part  102  includes an accommodating frame  104 , an accommodating-side auger  105 , and an auger partitioning wall  108 . 
         [0096]    The accommodating frame  104  is formed in a substantially box-like shape extending in the left-right direction and has an upper wall, a rear wall and a pair of side walls. The accommodating frame  104  has a substantially trapezoidal shape in a cross-sectional side view. The accommodating frame  104  has an upper portion whose left side wall is pierced in the left-right direction. 
         [0097]    The accommodating-side auger  105  is an auger screw extending in the left-right direction and is rotatably disposed in the upper portion of the accommodating frame  104 . The accommodating-side auger  105  has a left end disposed within the accommodating-side connecting part  103 . As will be described later, the accommodating-side connecting part  103  is provided leftward of a left end portion of the upper portion of the accommodating frame  104  in the left-right direction. 
         [0098]    The auger partitioning wall  108  connects between the pair of side walls of the accommodating frame  104 . The auger partitioning wall  108  is formed in the upper portion of the accommodating frame  104 . More specifically, the auger partitioning wall  108  extends frontward from an upper portion of the rear wall of the accommodating frame  104  and curves upward to have a substantially arcuate shape in a side cross-sectional view, in conformance with an outer profile of the accommodating-side auger  105 . 
         [0099]    An opening is thus defined by an upper-front peripheral edge of the auger partitioning wall  108 , the upper wall and the pair of side walls of the accommodating frame  104 . This opening serves as a waste toner leakage outlet  109  of the waste toner accommodating part  102 . 
         [0100]    The accommodating-side connecting part  103  has a substantially cylindrical shape, extending leftward from the left end portion on the upper portion of the accommodating frame  104  and then bending upward. The accommodating-side connecting part  103  has an upper end portion in which an accommodating-side communication port  106  is formed. The accommodating-side communication port  106  has a substantially cylindrical shape in a plan view. Interior and exterior of the waste toner cartridge  101  are in fluid communication with each other through the accommodating-side communication port  106 . 
         [0101]    The accommodating-side connecting part  103  also includes an accommodating-side shutter  107 . 
         [0102]    The accommodating-side shutter  107  is plate-like shaped and has a substantially L-shaped shape in a side view. The accommodating-side shutter  107  is pivotably movable, about a lower end portion thereof, between an open position and a closed position. The accommodating-side shutter  107  at the open position opens the accommodating-side communication port  106 , as shown in  FIGS. 1 and 2 . The accommodating-side shutter  107  at the closed position closes the accommodating-side communication port  106 , as shown in  FIGS. 3 through 5 . The accommodating-side shutter  107  is normally biased toward the closed position by a biasing spring (not shown). 
         [0103]    The waste toner cartridge  101  has a lower front end portion in which a shaft is provided to define an axis A. The waste toner cartridge  101  is pivotably movable about the axis A when accommodated in the waste toner cartridge accommodating section  84 . 
         [0104]    The waste toner cartridge  101  is thus movable between a connected position and a disconnected position within the main casing  2 . When the waste toner cartridge  101  is in the connected position, the accommodating-side communication port  106  opposes the belt-side communication port  68  of the belt cleaning unit  55  and is in fluid communication therewith, as shown in  FIGS. 1 and 2 . The waste toner cartridge  101  is thus connected to the belt cleaning unit  55  in the connected position. When the waste toner cartridge  101  is in the disconnected position, the accommodating-side communication port  106  is displaced frontward of the belt-side communication port  68  and the waste-toner cartridge  101  is disconnected from the belt cleaning unit  55 , as shown in  FIG. 3 through 5 . 
       4. Process Unit Mounted in the Main Casing 
       [0105]    In order to perform image formation, as shown in  FIG. 1 , the process unit  23  is disposed in the contact position within the main casing  2 . When the process unit  23  is in the contact position, each of the photosensitive drums  28  is in contact with the intermediate transfer belt  41  from below. 
         [0106]    Incidentally, the waste toner cartridge  101  is in the connected position. The accommodating-side communication port  106  of the accommodating-side connecting part  103  and the belt-side communication port  68  of the belt-side connecting part  57  are in communication with each other. At this time, the accommodating-side shutter  107  abuts on the belt-side connecting part  57  from its front side and is displaced to the open position against a biasing force of the biasing spring (not shown). The belt-side shutter  69  abuts on the accommodating-side connecting part  103  from its rear side and is displaced to the open position against a biasing force of the biasing spring (not shown). 
         [0107]    The front cover  7  is in the closed position to close the main body aperture  6 . 
       5. Operations for Collecting Materials Adhered to the Intermediate Transfer Belt 
       [0108]    During image forming operations, residual toner that has not been transferred onto the sheet P from each of the photosensitive drums  28  and paper dusts coming from the sheet P may be deposited on the intermediate transfer belt  41  that is in contact with the photosensitive drums  28 . These foreign matters adhered to the intermediate transfer belt  41  (residual toner and paper dust) are scraped off by the blade member  61  that is in contact with the intermediate transfer belt  41 , as the intermediate transfer belt  41  circularly moves. These matters scraped off from the intermediate transfer belt  41  are then collected into the auger accommodation part  63 . 
         [0109]    As the belt-side auger  62  rotates, the foreign materials collected into the auger accommodation part  63  are conveyed leftward within the auger accommodation part  63  and then to the belt-side connecting part  57 . The foreign materials conveyed to the belt-side connecting part  57  fall downward, due to self-weight of the materials themselves, pass through the belt-side communication port  68  and the accommodating-side communication port  106 , and come into the accommodating-side connecting part  103 . 
         [0110]    The foreign materials entering in the accommodating-side connecting part  103  are then conveyed rightward within the accommodating frame  104 , by the rotation of the accommodating-side auger  105 , following an upper surface of the auger partitioning wall  108 . As conveyed rightward by the accommodating-side auger  105 , the foreign materials partially leaks from the waste toner leakage outlet  109  and fall downward across an entire dimension thereof in the right-left direction within the accommodating frame  104 . 
         [0111]    In this way, the materials adhered to the intermediate transfer belt  41  are ultimately accumulated in the waste toner accommodating part  102  of the waste toner cartridge  101 . 
       6. Attachment and Detachment of the Waste Toner Cartridge and the Process Cartridges 
       [0112]    In order to remove the waste toner cartridge  101  and the process cartridges  26  from the main casing  2 , the process unit  23  is first pulled out to the external position. 
         [0113]    In order to pull out the process unit  23  to the external position, an operator first pivotally moves the front cover  7  counterclockwise in a right side view to, moving the front cover  7  from the closed position to the open position to open the main body aperture  6 , as shown in  FIG. 2 . 
         [0114]    Next, the operator directly grasps the waste toner cartridge  101  and pivotably moves the waste toner cartridge  101  about the axis A in a counterclockwise direction in a right side view. In other words, the waste toner cartridge  101  functions as an example of a claimed operation part. 
         [0115]    As the waste toner cartridge  101  is pivotally moved, the accommodating-side communication port  106  of the accommodating-side connecting part  103  is displaced frontward relative to the belt-side communication port  68  of the belt-side connecting part  57 . The accommodating-side connecting part  103  and the belt-side connecting part  57  are thus disconnected to each other, as shown in  FIG. 3 . 
         [0116]    At this time, in accordance with the pivotal movement of the waste toner cartridge  101 , the accommodating-side shutter  107  is also moved to the closed position by the biasing force of the biasing spring (not shown). Also, the belt-side shutter  69  is moved forward to the closed position by the biasing force of the biasing spring (not shown). The belt-side communication port  68  is thus closed by the belt-side shutter  69 . 
         [0117]    The waste toner cartridge  101  is thus moved to the disconnected position. 
         [0118]    Next, the operator grips the grip part  76  to move the process unit  23  downward, as shown in  FIG. 4 . 
         [0119]    The operator&#39;s operation to move the process unit  23  downward causes the photosensitive drums  28  to be separated from the intermediate transfer belt  41 . The process unit  23  is thus placed at the separation position. 
         [0120]    Next, the operator pulls out the process unit  23  frontward from the main casing  2 , while gripping the grip part  76 . 
         [0121]    The process unit  23  is thus moved to the external position, as shown in  FIG. 5 . As a result, the waste toner cartridge  101  and the process cartridges  26  are exposed from above. 
         [0122]    The operator can now remove the waste toner cartridge  101  and the process cartridges  26  from the process unit  23 . 
         [0123]    For removing the waste toner cartridge  101  and the process cartridges  26  from the process unit  23 , the operator can pull the waste toner cartridge  101  and the process cartridges  26  upward from the process unit  23 . 
         [0124]    In this way, maintenance and replacement of the waste toner cartridge  101  and the process cartridges  26  can be performed. 
         [0125]    The detachment of the waste toner cartridge  101  and the process cartridges  26  from the main casing  2  is thus completed. 
         [0126]    For mounting the waste toner cartridge  101  and the process cartridges  26  in the main casing  2 , the steps described above should be performed in reverse. 
         [0127]    Specifically, the waste toner cartridge  101  and the process cartridges  26  are mounted in the waste toner cartridge accommodating section  84  and the process cartridge accommodating sections  83  of the process frame  27 , respectively, from above. 
         [0128]    Next, the operator pushes the process unit  23  rearward to have the process unit  23  accommodated in the main casing  2 , as shown in  FIG. 4 . The process unit  23  is thus placed at the separation position. 
         [0129]    Then, grasping the grip part  76 , the operator moves the process unit  23  upward, causing the photosensitive drums  28  to be brought into contact with the intermediate transfer belt  41 , as shown in  FIG. 3 . The process unit  23  is thus moved to the contact position. 
         [0130]    Next, the operator grasps and pivotally moves the waste toner cartridge  101  about the axis A in a clockwise direction in a right side view. 
         [0131]    In accordance with the pivotal movement of the waste toner cartridge  101 , the accommodating-side connecting part  103  abuts on the belt-side shutter  69  from frontward, and the belt-side shutter  69  is caused to move (slide) rearward against the biasing force of the biasing spring (not shown), as shown in  FIG. 2 . Meanwhile, the belt-side connecting part  57  abuts on the accommodating-side shutter  107  from its rear side to cause the accommodating-side shutter  107  to pivotally move forward against the biasing force of the biasing spring (not shown). 
         [0132]    As the waste toner cartridge  101  is further pivotally moved, the accommodating-side communication port  106  of the accommodating-side connecting part  103  and the belt-side communication port  68  of the belt-side connecting part  57  oppose each other to establish fluid communication therebetween. The belt-side shutter  69  and the accommodating-side shutter  107  are at the respective open positions. 
         [0133]    The waste toner cartridge  101  is thus positioned in the connected position. 
         [0134]    Next, the operator pivotably moves the front cover  7  in the clockwise direction in a right side view for placing the front cover  7  in the closed position. The main body aperture  6  is closed accordingly, as shown in  FIG. 1 . 
         [0135]    The attachment of the waste toner cartridge  101  and the process cartridges  26  to the main casing  2  is thus completed. 
       7. Operational and Technical Advantages 
       [0136]    (1) With the above-described structure of the printer  1  according to the first embodiment, the waste toner cartridge  101  is pivotably movable between the connected position and the disconnected position when the process unit  23  is placed at the contact position in the internal position. This means that the waste toner cartridge  101  can be moved to the connected position, after the process unit  23  and the photosensitive drums  28  are respectively positioned relative to the main casing  2 . In other words, the accommodating-side connecting part  103  of the waste toner cartridge  101  and the belt-side connecting part  57  of the belt cleaning unit  55  can be brought into communication with each other after positioning of the process unit  23  and the photosensitive drums  28  are performed. 
         [0137]    Further, the process unit  23  is in the contact position when the waste toner cartridge  101  is in the connected position, as shown in  FIG. 1 . 
         [0138]    With this structure, since the waste toner cartridge  101  and the belt cleaning unit  55  are in communication with each other when the process unit  23  is in the contact position, materials adhered to the intermediate transfer belt  41  during image formation can be reliably collected. Moreover, since the waste toner cartridge  101  is operated after the process unit  23  is fixed in position relative to the main casing  2 , operating the waste toner cartridge  101  can be carried out in a simple manner. 
         [0139]    In order to placing the process unit  23  in the external position, the waste toner cartridge  101  is first pivotably moved from the connected position to the disconnected position when the process unit  23  is positioned at the contact position in the internal position, as shown in  FIG. 3 . Then, the process unit  23  is moved from the contact position to the separation position, as shown in  FIG. 4 . That is, the waste toner cartridge  101  is in the disconnected position when the process unit  23  is in the separation position. 
         [0140]    This configuration realizes disconnection of the waste toner cartridge  101  and the belt cleaning unit  55  in a state where the process unit  23  and the photosensitive drums  28  are respectively fixed in position relative to the main casing  2 , as shown in  FIGS. 2 and 3 . Hence, disconnection of the waste toner cartridge  101  and the belt cleaning unit  55  can be performed stably, although the waste toner cartridge  101  is provided in the process unit  23 . 
         [0141]    Further, the process unit  23  can be moved to the external position in a state where the photosensitive drums  28  are separated from the intermediate transfer belt  41 , and the waste toner cartridge  101  is disconnected from the belt cleaning unit  55 , as shown in  FIGS. 4 and 5 . This construction can prevent the accommodating-side connecting part  103  of the waste toner cartridge  101  and the belt-side connecting part  57  of the belt cleaning unit  55  from being damaged while the process unit  23  is moved (pulled out) to the external position from the separation position. 
         [0142]    Further, as shown in  FIGS. 2 and 3 , since the waste toner cartridge  101  can be moved between the connected position and the disconnected position while the process unit  23  is placed at the contact position in the internal position, the accommodating-side connecting part  103  of the waste toner cartridge  101  and the belt-side connecting part  57  of the belt cleaning unit  55  can be reliably connected to each other. 
         [0143]    (2) According to the printer  1  of the first embodiment, the waste toner cartridge  101  can be reliably pivotably moved between the connected position and the disconnected position as shown in  FIGS. 2 and 3 , since the operator directly grips and operates the waste toner cartridge  101 . 
         [0144]    (3) According to the printer  1  of the first embodiment, as shown in  FIG. 5 , the process unit  23  is pulled out frontward in the front-rear direction (also referred to as a pull-out direction). The waste toner cartridge  101  is exposed from the main casing  2  even sooner than the process cartridges  26  when the process unit  23  is moved toward the external position. 
         [0145]    For this reason, the waste toner cartridge  101  can be detached from and attached to the process unit  23  in such a state that the process unit  23  is partially withdrawn from the main casing  2  and only the waste toner cartridge  101  is exposed from the main casing  2 . Also, the operator can easily pivotably move the waste toner cartridge  101  between the connected position and the disconnected position, since the waste toner cartridge  101  is disposed most downstream in the pull-out direction in the process unit  23 . 
         [0146]    (4) According to the printer  1  of the first embodiment, as shown in  FIGS. 3 and 4 , the process unit supports the process cartridges  26  having the photosensitive drums  28 . Thus the photosensitive drums  28  can be moved together with the process unit  23  when the process unit  23  is in the internal position. 
         [0147]    Hence, the process unit  23  is reliably movable between the contact position at which the photosensitive drums  28  contact the intermediate transfer belt  41  and the separation position at which the photosensitive drums  28  separate from the intermediate transfer belt  41 . 
         [0148]    (5) According to the printer  1  of the first embodiment, as shown in  FIGS. 3 and 4 , even if the process unit  23  supports the plurality of process cartridges  26 , the process unit  23  can reliably move between the contact position (the photosensitive drums  28  contact the intermediate transfer belt  41 ) and the separation position (the photosensitive drums  28  separate from the intermediate transfer belt  41 ). 
       8. Variation of the First Embodiment 
       [0149]    In the first embodiment described above, for removing the waste toner cartridge  101  and the process cartridges  26  from the main casing  2 , the front cover  7  is first moved to the open position and subsequently the waste toner cartridge  101  is manually moved to the disconnected position. 
         [0150]    In contrast, as a variation of the first embodiment, the waste toner cartridge  101  may be moved to the disconnected position in conjunction with the operation to move the front cover  7  to the open position using a known linking mechanism. 
         [0151]    With this configuration, the operation to open the front cover  7  and the movement (displacement) of the waste toner cartridge  101  from the connected position to the disconnected position can be mechanically linked to each other. 
         [0152]    For this reason, the process unit  23  can be displaced to the external position after the waste toner cartridge  101  is reliably placed at the disconnected position. 
         [0153]    Further, this configuration of the variation of the first embodiment can achieve the same technical advantages as the first embodiment. 
       Second Embodiment 
       [0154]    Next, a waste toner cartridge  115  and a belt-side connecting part  124  according to a second embodiment of the present invention will be described with reference to  FIGS. 6 through 10 , wherein like parts and components are designated with the same reference numerals with those of the first embodiment to avoid duplicating description. 
       1. Configuration in the Second Embodiment 
       [0155]    The belt cleaning unit  55  of the first embodiment includes the belt-side connecting part  57  that is incapable of moving relative to the belt cleaner  56 , as shown in  FIGS. 2 and 3 . The process unit  23  of the first embodiment includes the waste toner cartridge  101  that is pivotally movable about the axis A between the connected position (connected to the belt cleaning unit  55 ) and the disconnected position (disconnected from the belt cleaning unit  55 ) when accommodated within the waste toner cartridge accommodating section  84 . 
         [0156]    In contrast, in the second embodiment, the process unit  23  includes the waste toner cartridge  115 . As shown in  FIG. 6 , unlike the waste toner cartridge  101  of the first embodiment, the waste toner cartridge  115  of the second embodiment cannot pivotally move when accommodated in the waste toner cartridge accommodating section  84 . The belt cleaning unit  55  includes the belt-side connecting part  124  of the second embodiment that is pivotably movable about an axis B relative to the belt cleaner  56 , the axis B being coincident with an axis of the belt-side auger  62 . 
         [0157]    The waste toner cartridge  115  is accommodated in the waste toner cartridge accommodating section  84 . The waste toner cartridge  115  includes a waste toner accommodating part  116  and an accommodating-side connecting part  117 . 
         [0158]    The waste toner accommodating part  116  includes an accommodating frame  118 , an accommodating-side auger  119 , and an auger partitioning wall  122 . 
         [0159]    The accommodating frame  118  is formed in a substantially box-like shape extending in the left-right direction and has an upper wall, a rear wall and a pair of side walls. The accommodating frame  118  has a substantially rectangular shape in a side cross-sectional view. The accommodating frame  118  has an upper rear portion whose left side wall is pierced in the left-right direction. 
         [0160]    The accommodating-side auger  119  is an auger screw extending in the left-right direction. The accommodating-side auger  119  is disposed in the upper rear portion of the accommodating frame  118 . Moreover, the accommodating-side auger  119  has a left end disposed within the accommodating-side connecting part  117  (described later). The accommodating-side connecting part  117  is provided leftward of a left end portion of the accommodating frame  118  in the left-right direction. 
         [0161]    The auger partitioning wall  122  connects between the pair of side walls of the accommodating frame  118 . The auger partitioning wall  122  extends frontward from a front surface on an upper portion of the rear wall of the accommodating frame  118  and curving upward to have a substantially arcuate shape in a side cross-sectional view, in conformance with an outer profile of the accommodating-side auger  119 . 
         [0162]    Further, an opening is defined by an upper-front peripheral edge of the auger partitioning wall  122 , the upper wall and the pair of side walls of the accommodating frame  118 . This opening serves as a waste toner leakage outlet  123  of the waste toner accommodating part  116 . 
         [0163]    The accommodating-side connecting part  117  has a substantially cylindrical shape, extending leftward from the left end portion on the upper-rear portion of the accommodating frame  118  and then bending upward. The accommodating-side connecting part  117  has an upper end portion in which an accommodating-side communication port  120  is formed. The accommodating-side communication port  120  has a substantially circular shape in a plan view. Interior and exterior of the waste toner cartridge  115  are in fluid communication with each other through the accommodating-side communication port  120 . The accommodating-side connecting part  117  includes an accommodating-side shutter  121 . 
         [0164]    The accommodating-side shutter  121  is plate-like shaped and has a substantially L-shaped shape in a side view. The accommodating-side shutter  121  is pivotably movable, about a lower end portion thereof, between an open position and a closed position. The accommodating-side shutter  121  at the open position opens the accommodating-side communication port  120 , as shown in  FIGS. 6 and 7 . The accommodating-side shutter  121  at the closed position closes the accommodating-side communication port  121 , as shown in  FIGS. 8 through 10 . 
         [0165]    The belt-side connecting part  124  has a substantially cylindrical shape. As shown in  FIG. 6 , the belt-side connecting part  124  extends leftward from the left end portion of the auger accommodation part  63  of the belt cleaner frame  60 , then bends downward and frontward, and then extends downward. The belt-side connecting part  124  has a lower end portion in which a belt-side communication port  125  is formed. The belt-side communication port  125  has a substantially circular in a bottom view. Interior and exterior of the belt cleaning unit  55  are in fluid communication with each other through the belt-side communication port  125 . The belt-side connecting part  124  is also provided with a belt-side shutter (not shown). The belt-side shutter is movable between an open position opening the belt-side communication port  125  and a closed position closing the belt-side communication port  125 . 
         [0166]    The belt-side connecting part  124  is pivotally movable about the axis B relative to the belt cleaner frame  60 . 
         [0167]    With this structure, the belt-side connecting part  124  is movable between a connected position and a disconnected position within the main casing  2 . In the connected position, the belt-side connecting part  124  opposes the accommodating-side communication port  120  of the waste toner cartridge  115  and is in fluid communication therewith, as shown in  FIGS. 6 and 7 . The belt-side connecting part  124  is thus connected to the waste toner cartridge  115 . In the disconnected position, the belt-side communication port  125  is moved frontward of the accommodating-side communication port  120  and the belt-side connecting part  124  is thus disconnected from the waste toner cartridge  115 , as shown in  FIG. 8 through 10 . 
         [0168]    Incidentally, the left end portion of the belt-side auger  62  (disposed within the auger accommodating part  63 ) is disposed within the belt-side connecting part belt-side connecting part  124 . 
       2. Process Unit Mounted in the Main Casing in the Second Embodiment 
       [0169]    As shown in  FIG. 6 , the process unit  23  is disposed in the contact position within the main casing  2 . When the process unit  23  is in the contact position, each of the photosensitive drums  28  is in contact with the intermediate transfer belt  41  from below. 
         [0170]    The belt-side connecting part  124  is in the connected position. Thus the belt-side communication port  125  of the belt-side connecting part  124  is in fluid communication with the accommodating-side communication port  120  of the accommodating-side connecting part  117  of the waste toner cartridge  115 . At this time, the belt-side shutter (not shown) and the accommodating-side shutter  121  are both in the open position. 
         [0171]    The front cover  7  is in the closed position. The main body aperture  6  is thus closed. 
       3. Operations for Collecting Materials Adhered to the Intermediate Transfer Belt in the Second Embodiment 
       [0172]    As described in the first embodiment, foreign matters adhered to the intermediate transfer belt  41  (such as residual toner and paper dust) are scraped off by the blade member  61  that is in contact with the intermediate transfer belt  41 , as the intermediate transfer belt  41  circularly moves. These foreign matters scraped off from the intermediate transfer belt  41  are then collected into the belt-side connecting part  124  by the belt-side auger  62 . 
         [0173]    The foreign materials collected in the auger accommodation part  124  fall downward, due to self-weight of the materials themselves, pass through the belt-side communication port  125  and the accommodating-side communication port  120 , and enters into the accommodating-side connecting part  117 . 
         [0174]    The foreign materials coming into the accommodating-side connecting part  117  are then conveyed rightward within the accommodating frame  118  by the rotation of the accommodating-side auger  119 , following an upper surface of the auger partitioning wall  122 . As conveyed rightward by the accommodating-side auger  119 , the foreign materials partially leaks from the waste toner leakage outlet  123  and fall downward across an entire dimension thereof in the right-left direction within the accommodating frame  118 . 
         [0175]    The materials adhered to the intermediate transfer belt  41  are thus ultimately accumulated in the waste toner accommodating part  116  of the waste toner cartridge  115 . 
       4. Attachment and Detachment of the Waste Toner Cartridge and the Process Cartridges in the Second Embodiment 
       [0176]    In order to remove the waste toner cartridge  115  and the process cartridges  26  from the main casing  2 , the process unit  23  is first pulled out to the external position. 
         [0177]    In order to pull out the process unit  23  to the external position, the operator pivotally moves the front cover  7  counterclockwise in a right side view to the open position to open the main body aperture  6 , as shown in  FIG. 7 . 
         [0178]    Next, the operator directly grasps the belt-side connecting part  124  and pivotably moves the belt-side connecting part  124  about the axis B in the counterclockwise direction in a right side view. In other words, the belt-side connecting part  124  functions as another example of the claimed operation part. 
         [0179]    As the belt-side connecting part  124  is pivotally moved, the belt-side communication port  125  of the belt-side connecting part  124  is displaced frontward and upward relative to the accommodating-side communication port  120  of the accommodating-side connecting part  117  to be distanced therefrom, as shown in  FIG. 8 . The belt-side connecting part  124  is thus disconnected from the accommodating-side connecting part  117 . 
         [0180]    Then the operator moves the belt-side shutter (not shown) to the closed position to close the belt-side communication port  125 . The operator also moves the accommodating-side shutter  121  to its closed position to close the accommodating-side communication port  120 . 
         [0181]    The belt-side connecting part  124  is thus displaced to the disconnected position from the connected position. 
         [0182]    Subsequently, with the same procedures as the first embodiment, the operator moves the process unit  23  to the separation position, as shown in  FIG. 9 , and then to the external position, as shown in  FIG. 10 . 
         [0183]    The waste toner cartridge  115  and the process cartridges  26  are then removed from the process unit  23 . 
         [0184]    To detach the waste toner cartridge  115  and the process cartridges  26  from the process unit  23 , the operator pulls the waste toner cartridge  115  and the process cartridges  26  upward from the process unit  23 . 
         [0185]    Maintenance and replacement of the waste toner cartridge  115  and the process cartridges  26  can be performed. 
         [0186]    The detachment of the waste toner cartridge  115  and the process cartridges  26  from the main casing  2  is thus completed. 
         [0187]    In order to mount the waste toner cartridge  115  and the process cartridges  26  in the main casing  2 , the steps described above are performed in reverse. 
         [0188]    Specifically, the waste toner cartridge  115  and the process cartridges  26  are accommodated in the waste toner cartridge accommodating section  84  and the process cartridge accommodating sections  83  of the process frame  27 , respectively, from above. 
         [0189]    Next, with the same steps as in the first embodiment, the process unit  23  is moved to the separation position, as shown in  FIG. 9 , and to the contact position, as shown in  FIG. 10 . 
         [0190]    The operator operates the belt-side shutter (not shown) to move the same to the open position to open the belt-side communication port  125 . The operator also operates the accommodating-side shutter  121  to move the same to the open position to open the accommodating-side communication port  120 . 
         [0191]    Next, the operator pivotally moves the belt-side connecting part  124  about the axis B in the counterclockwise direction in a right side view. 
         [0192]    The belt-side connecting part  124  is thus moved to the connected position. 
         [0193]    Finally, as shown in  FIG. 6 , the front cover  7  of the main casing  2  is pivotably moved clockwise in a right side view to be displaced to the closed position to close the main body aperture  6 . 
         [0194]    The attachment of the waste toner cartridge  115  and the process cartridges  26  to the main casing  2  is thus completed. 
       5. Operational and Technical Advantages 
       [0195]    According to the printer  1  of the second embodiment, as shown in  FIGS. 7 and 8 , the belt-side connecting part  124  can be pivotably moved between the connected position and the disconnected position when the process unit  23  is disposed at the contact position in the internal position. In other words, the belt-side connecting part  124  of the belt cleaning unit  55  can be connected to the accommodating-side connecting part  117  of the waste toner cartridge  115  to be in fluid communication therewith (i.e., the belt-side connecting part  124  is in the connected position) after the process unit  23  and the photosensitive drums  28  are respectively fixed in position relative to the main casing  2 . 
         [0196]    In other words, the process unit  23  is situated in the contact position when the belt-side connecting part  124  is in the connected position, as shown in  FIG. 6 . 
         [0197]    With this structure, since the waste toner cartridge  115  and the belt cleaning unit  55  are in communication with each other when the process unit  23  is in the contact position, the materials adhered to the intermediate transfer belt  41  during image formation can be reliably collected. Moreover, since the waste toner cartridge  115  is operated after the process unit  23  is fixed relative to the main casing  2 , the operator can easily manipulate the waste toner cartridge  115 . 
         [0198]    In order to moving the process unit  23  to the external position, the operator first moves the belt-side connecting part  124  from the connected position to the disconnected position when the process unit  23  is in the contact position of the internal position, as shown in  FIG. 8 . Then, the operator moves the process unit  23  from the contact position to the separation position, as shown in  FIG. 9 . That is, the belt-side connecting part  124  is in the disconnected position when the process unit  23  is in the separation position. 
         [0199]    This configuration realizes disconnection of the waste toner cartridge  115  and the belt cleaning unit  55  in a state where the process unit  23  and the photosensitive drums  28  are respectively fixed in position relative to the main casing  2 , as shown in  FIGS. 7 and 8 . Hence, disconnection of the waste toner cartridge  115  and the belt cleaning unit  55  can be performed stably, although the waste toner cartridge  115  is provided in the process unit  23 . 
         [0200]    Further, the process unit  23  can be moved (pulled out) to the external position from the separation position in a state where the photosensitive drums  28  are separated from the intermediate transfer belt  41  and the belt-side connecting part  124  of the belt cleaning unit  55  is disconnected from the accommodating-side connecting part  117  of the waste toner cartridge  115 , as shown in  FIGS. 9 and 10 . This construction can prevent the accommodating-side connecting part  117  and the belt-side connecting part  124  from being damaged while the process unit  23  is pulled out to the external position. 
         [0201]    Further, as shown in  FIGS. 7 and 8 , since the belt-side connecting part  124  can be displaced between the connected position and the disconnected position while the process unit  23  is placed at the contact position in the internal position, the belt-side connecting part  124  of the belt cleaning unit  55  can be reliably connected to the accommodating-side connecting part  117  of the waste toner cartridge  115 . 
         [0202]    Further, the construction of the second embodiment can realize the same operational and technical advantages as in the first embodiment. 
       6. Variation of the Second Embodiment 
       [0203]    In the above-described second embodiment, for removing the waste toner cartridge  115  and the process cartridges  26  from the main casing  2 , the front cover  7  is first moved to the open position and subsequently the belt-side connecting part  124  is manually moved to the disconnected position. 
         [0204]    In contrast, as a variation of the second embodiment, the belt-side connecting part  124  may be moved to the disconnected position in conjunction with the operation to move the front cover  7  to the open position using a known linking mechanism. 
         [0205]    With this configuration, as shown in  FIGS. 6 and 8 , the operation to open the front cover  7  and the movement (displacement) of the belt-side connecting part  124  from the connected position to the disconnected position can be mechanically linked to each other. 
         [0206]    Therefore, the process unit  23  can be moved to the external position after the belt-side connecting part  124  is reliably placed in the disconnected position. 
         [0207]    The configuration of the variation of the second embodiment also realizes the same operational and technical advantages as in the second embodiment. 
         [0208]    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.