Patent Publication Number: US-9841705-B2

Title: Packaging unit including image forming apparatus with developer cartridge mounted therein and packaging member in which image forming apparatus is packaged

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation of U.S. application Ser. No. 13/315,760 filed Dec. 9, 2011, which claims priority from Japanese Patent Application No. 2010-288092 filed Dec. 24, 2010. The entire contents of the above noted applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a packaging unit 
     BACKGROUND 
     One example of a conventional electrophotographic image-forming device well known in the art is a printer provided with a detachably mounted toner cartridge for accommodating toner. Methods for packaging this type of printer for the purposes of shipping, for example, have been studied. In one method, the body of the printer and the toner cartridge are packaged in separate boxes, while other methods package the printer body and toner cartridge in the same box, with the toner cartridge outside of the printer body. 
     In both packaging methods described above, the toner cartridge is removed from the printer body for shipping. Consequently, a larger number of boxes is required when packaging the printer body and toner cartridge separately, and the size of the box increases when the printer body and toner cartridge are packaged together. 
     SUMMARY 
     Therefore, it is an object of the present invention to provide a packaging method for packaging an image-forming device by which the image-forming device and toner cartridge can be compactly accommodated while preventing toner contamination to the image-forming device and toner cartridge. It is another object of the present invention to provide a packaging unit for packaging the image-forming device according to the packaging method. 
     In order to attain the above and other objects, the invention provides a packaging unit including an image forming apparatus and a packaging member. A cartridge is detachably mounted in the image forming apparatus. The cartridge accommodates developer therein. The image forming apparatus is configured to form an image using the developer. The cartridge is formed with a first opening for allowing the developer to discharge outside from the cartridge when the cartridge is in a first posture. The cartridge is in the first posture when the image is formed. The packaging member packages the image forming apparatus therein in such a posture that the cartridge is in a second posture where leakage of the developer from the first opening is unlikely to occur as compared with a posture of the image forming apparatus in which the cartridge is in the first posture. 
     According to another aspect, the present invention provides a method comprising: mounting a cartridge into an image forming apparatus, the cartridge accommodating developer therein, the image forming apparatus being configured to form an image using the developer, the cartridge being formed with a first opening for allowing the developer to discharge outside from the cartridge when the cartridge is in a first posture, the cartridge being in the first posture when the image is formed; and packaging the image forming apparatus in a packaging member in such a posture that the cartridge is in a second posture where leakage of the developer from the first opening is unlikely to occur as compared with a posture of the image forming apparatus in which the cartridge is in the first posture. 
     According to another aspect, the present invention provides a packaging unit including an image forming apparatus and a packaging member. A cartridge is detachably mounted into the image forming apparatus. The image forming apparatus is configured to form an image using the developer. The cartridge accommodates developer therein. The cartridge is formed with an opening and having an edge defining the opening. The opening allows the developer to discharge outside from the cartridge when at least part of the edge is positioned at a position lower than a level of the developer accommodated in the cartridge. The image forming apparatus is packaged in the packaging member in such a posture that the entire edge is positioned at a position higher than the level of the developer accommodated in the cartridge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The particular features and advantages of the invention as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic cross-sectional view of a color laser printer as an image forming apparatus according to a first embodiment of the present invention; 
         FIG. 2  is a perspective view of a drum cartridge provided in the color laser printer as viewed from an upper, front, right side in the first embodiment: 
         FIG. 3  is a perspective view of a toner cartridge mounted to the color laser printer as viewed from an upper, rear, left side in the first embodiment; 
         FIG. 4  is a partial cross-sectional view of the toner cartridge shown in  FIG. 3 ; 
         FIG. 5( a )  is a perspective view of an input member provided on the toner cartridge when the input member is disposed at a protruding position in the first embodiment; 
         FIG. 5( b )  is a perspective view of the input member when the input member is disposed at a retracted position in the first embodiment; 
         FIG. 5( c )  is an upper view of the input member when the input member is disposed at the protruding position in the first embodiment; 
         FIG. 6  is a side view of a process cartridge provided on the image forming apparatus in a state that a shutter operating unit is at a closed position in the first embodiment; 
         FIG. 7  is a cross-sectional view of the process cartridge shown in  FIG. 6  in the first embodiment; 
         FIG. 8  is a side view of a process cartridge provided on the image forming apparatus in a state that a shutter operating unit is at an open position in the first embodiment; 
         FIG. 9  is a cross-sectional view of the process cartridge shown in  FIG. 8 ; 
         FIG. 10  is a cross-sectional view showing the color laser printer in a state that a front cover is opened in the first embodiment; 
         FIG. 11  is a cross-sectional view showing the color laser printer in a state that the front cover is closed in the first embodiment; 
         FIG. 12  is a cross-sectional view showing the color laser printer in a state that the process cartridge is installed in the color laser printer in the first embodiment; 
         FIG. 13  is a perspective view of a cartridge cover for covering the toner cartridge in the first embodiment; 
         FIG. 14( a )  is a perspective view of the toner cartridge covered with the cartridge cover as viewed from an upper, front, left side in the first embodiment; 
         FIG. 14( b )  is an upper view of the toner cartridge shown in  FIG. 14( a ) ; 
         FIG. 15  is a perspective view showing the toner cartridge fixed to the color laser with a tape in the first embodiment; 
         FIG. 16  is a cross-sectional view showing the toner cartridge fixed to the color laser with the tape in the first embodiment; 
         FIG. 17( a )  and  FIG. 17( b )  are perspective views of packaging member; 
         FIG. 18( a )-( c )  are side views showing how to pack the color laser in the packaging member according to the first embodiment; 
         FIG. 19  is a partial cross-sectional view showing the toner cartridge accommodated in a developer unit provided on the color laser in the first embodiment; 
         FIG. 20  is a side view of a color laser as an image forming apparatus according to a second embodiment in a state that an image is formed; 
         FIG. 21  is a side view of the color laser of  FIG. 20  in a state that a toner cartridge is removed from the color laser in the second embodiment; 
         FIG. 22  is a side view of the color laser of  FIG. 20  in a state that the toner cartridge is being installed in the color laser in the second embodiment; 
         FIG. 23  is a side view of the color laser of  FIG. 22  in a state that the toner cartridge has been installed in the color laser in the second embodiment; 
         FIG. 24  is a side view showing a state that the color laser is packaged in a packaging member in the second embodiment; and 
         FIG. 25  is a side view showing a state that the color laser is packaged in a packaging member in a modification of the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A packaging unit according to embodiments of the invention will be described while referring to the accompanying drawings wherein like parts and components are designated by the same reference numerals to avoid duplicating description. 
     The terms “upward”, “downward”, “upper”, “lower”, “above”, “below”, “beneath”, “right”, “left”, “front”, “rear” and the like will be used throughout the description assuming that an image forming apparatus of the packaging unit is disposed in an orientation in which it is intended to be used. In use, the image forming apparatus is disposed as shown in  FIG. 1 . 
     1. Laser Printer 
     As shown in  FIG. 1 , a laser printer  1  is provided with a main casing  2 . An access opening  17  is formed in the front surface of the main casing  2 . A front cover  3  is rotatably provided on the front surface of the main casing  2  and can be rotated between a second closed position for covering the access opening  17  and a second open position for exposing the access opening  17 . 
     In the following description, the side of the laser printer  1  faced by a user operating the same (i.e., the side on which the front cover  3  is provided) will be referred to as the “front side,” and rear, up, down, left, and right directions will be defined based on the user&#39;s perspective when observing any component of the laser printer  1  from the front side. 
     The main casing  2  is also provided with a process cartridge  4 . As shown in  FIGS. 1 and 12 , the process cartridge  4  can be mounted in or removed from the main casing  2  through the access opening  17  when the front cover  3  is in the second open position. The process cartridge  4  includes a drum cartridge  5 , and a toner cartridge  6 . The toner cartridge  6  holds toner and is detachably mounted on the drum cartridge  5 . 
     The drum cartridge  5  includes a drum frame  7 . The drum frame  7  retains a photosensitive drum  8 , a charger  9 , and a cleaner  10  in the rear end portion thereof. 
     The photosensitive drum  8  has a drum shaft  11  oriented in the left-to-right direction and is disposed in the drum frame  7  so as to be rotatable about the drum shaft  11 . 
     The charger  9  is disposed diagonally rearward and above the photosensitive drum  8 , while the cleaner  10  is disposed on the rear side of the photosensitive drum  8 . 
     A developing device  12  is retained in the drum cartridge  5  at a position forward from the photosensitive drum  8 . The developing device  12  includes a developing device case  13  and, a developing roller  14 , a supply roller  15 , and an auger  16  are provided inside the developing device case  13 . 
     The developing roller  14  has a developing roller shaft  18  oriented in the left-to-right direction and is provided in the developing device case  13  so as to be rotatable about the developing roller shaft  18 . Part of the peripheral surface of the developing roller  14  is exposed in the rear end of the developing device case  13  and contacts the peripheral surface of the photosensitive drum  8  on the front side thereof. 
     The supply roller  15  is disposed on the front lower side of the developing roller  14 . The supply roller  15  includes a supply roller shaft  19  oriented in the left-to-right direction and is provided in the developing device case  13  so as to be rotatable about the supply roller shaft  19 . The peripheral surface of the supply roller  15  is in contact with the peripheral surface of the developing roller  14 . 
     The auger  16  is disposed in front of the supply roller  15 . The auger  16  has an auger shaft  20  oriented in the left-to-right direction and is provided in the developing device case  13  so as to be rotatable about the auger shaft  20 . 
     Toner in the toner cartridge  6  can be supplied into the developing device case  13  when the toner cartridge  6  is mounted on the drum cartridge  5 . Toner provided to the developing device case  13  is supplied from the peripheral surface of the supply roller  15  to the peripheral surface of the developing roller  14  by the rotations of the developing roller  14  and supply roller  15 . Toner supplied to the developing roller  14  is carried on the surface of the developing roller  14  as a thin layer of uniform thickness. In short, the developing device  12  is configured of the toner cartridge  6  and a developing unit. 
     An exposure unit  21  is disposed inside the main casing  2  above the process cartridge  4 . The exposure unit  21  is provided with a laser light source or the like for emitting a laser beam LB toward the surface of the photosensitive drum  8 . 
     During image formation, the photosensitive drum  8  rotates at a constant speed clockwise when viewed from the left side. While the photosensitive drum  8  rotates, the charger  9  applies a uniform charge to the peripheral surface of the photosensitive drum  8  through corona discharge, after which the exposure unit  21  irradiates the laser beam LB onto the charged surface. The electric charge is selectively removed from areas of the surface of the photosensitive drum  8  that were exposed to the laser beam LB, forming an electrostatic latent image thereon. As the photosensitive drum  8  rotates and brings the electrostatic latent image opposite the developing roller  14 , toner is transferred from the developing roller  14  to the latent image, producing a toner image on the surface of the photosensitive drum  8 . 
     A transfer roller  22  is disposed inside the main casing  2  beneath the photosensitive drum  8 . The transfer roller  22  has a transfer roller shaft  23  oriented in the left-to-right direction and is provided so as to be rotatable about the transfer roller shaft  23 . 
     A paper cassette  24  is provided in the bottom section of the main casing  2  for accommodating sheets of paper. Various rollers feed the paper one sheet at a time from the front end of the paper cassette  24  to a transfer position between the photosensitive drum  8  and the transfer roller  22 . 
     As the sheets of paper pass between the photosensitive drum  8  and transfer roller  22 , toner images are transferred from the surface of the photosensitive drum  8  onto the paper. After toner images are transferred onto the paper, the sheets are conveyed to a fixing unit  26 . In the fixing unit  26 , the toner images are fixed to the paper by heat and pressure. After the images are formed on the paper, the sheets of paper are discharged into a discharge tray  25 . 
     2. Detailed Description of the Process Cartridge 
     (1) Drum Cartridge 
     (1-1) Drum Frame 
     As shown in  FIG. 2 , the drum frame  7  includes a pair of side plates  31  arranged parallel to each other and separated in the left-to-right direction, a bottom plate  32  bridging the lower edges of the side plates  31 , and a top plate  33  bridging the top edges of the side plates  31  in approximately the rear half of the same. 
     Both ends of the drum shaft  11  provided in the photosensitive drum  8  penetrate the corresponding side plates  31  near the rear ends thereof and protrude outward from the same. With this configuration, the photosensitive drum  8  is rotatable about the drum shaft  11  while interposed between the left and right side plates  31 . 
     Developing roller shaft receiving holes  34  are formed in both side plates  31  at positions in front of and separated from the drum shaft  11 . The developing roller shaft receiving holes  34  are elongated holes that penetrate the side plates  31 . The developing roller shaft receiving holes  34  are elongated in the front-to-rear direction and have a greater vertical dimension than the diameter of the developing roller shaft  18 . The left and right ends of the developing roller shaft  18  are rotatably inserted into the corresponding developing roller shaft receiving holes  34 . 
     Supply roller shaft receiving holes  35  are also formed in both side plates  31  at positions diagonally forward and below the developing roller shaft receiving holes  34  and separated therefrom. The supply roller shaft receiving holes  35  are elongated holes that penetrate the side plates  31 . The supply roller shaft receiving holes  35  are elongated in the front-to-rear direction and have a greater vertical dimension than the diameter of the supply roller shaft  19 . Left and right ends of the supply roller shaft  19  are rotatably inserted into the corresponding supply roller shaft receiving holes  35 . 
     Cutout parts  36  are formed in the side plates  31  at positions forward and separated from the supply roller shaft receiving holes  35 . The cutout parts  36  are substantially U-shaped and open upward. 
     The bottom plate  32  bridges the bottom edges of the side plates  31 , extending between the front edges of the side plates  31  and a position confronting the front peripheral surface of the photosensitive drum  8  (see  FIG. 7 ). With this construction, the peripheral surface of the photosensitive drum  8  is exposed on the bottom to the rear of the bottom plate  32 . 
     The top plate  33  bridges the top edges of the side plates  31  in the rear half of the same. The top plate  33  is positioned such that the front edge thereof is substantially flush with the rear edges of the cutout parts  36  in a side view. 
     An opening  37  is formed in the top plate  33  in the portion opposing the photosensitive drum  8  from above. The opening  37  spans the entire left-to-right width of the top plate  33 . With this construction, the peripheral surface of the photosensitive drum  8  is exposed on the top through the opening  37 . The laser beam LB emitted from the exposure unit  21  (see  FIG. 1 ) passes through the opening  37  and is irradiated onto the peripheral surface of the photosensitive drum  8 . The charger  9  and cleaner  10  are accommodated inside the top plate  33  farther rearward than the opening  37 . 
     (1-2) Developing Device 
     As shown in  FIGS. 2 and 7 , the developing device case  13  is integrally provided with a main body part  41  and shutter support parts  42 . The main body part  41  accommodates the developing roller  14 , supply roller  15 , and auger  16 . The shutter support parts  42  are plate-shaped and extend forward from the left and right ends of the main body part  41 . Each shutter support part  42  extends forward from the main body part  41  to a position confronting the cutout parts  36  of the drum frame  7  in the left-to-right direction. The front ends of the shutter support parts  42  are substantially arc-shaped. 
     Retaining holes  43  are formed in the shutter support parts  42 , penetrating the shutter support parts  42  in the left-to-right direction. The retaining holes  43  are substantially circular in a side view. 
     Guide parts  40  are formed in the left and right inner surfaces of the corresponding shutter support parts  42  at positions along the front edges thereof. Each guide part  40  is formed as a groove that extends from the front edge of the corresponding shutter support part  42  in the front-to-rear direction and is in communication with the corresponding retaining hole  43 . The width of the groove shape is tapered so as to grow narrower toward the rear. The width of the groove on the rear edge of the guide part  40  is substantially equivalent to the width of the groove shape formed by a first engaging part  45  described later. 
     The developing device case  13  has a front wall  47  formed in a curved plate shape. The front wall  47  curves along the rear half of the peripheral edges of the retaining holes  43 . The front wall  47  bridges the left and right shutter support parts  42  and is continuously formed with the main body part  41  near the circumferential center of the front wall  47 . Three developer openings  48  (see  FIG. 2 ) are formed in the vertical center portion of the front wall  47  connected to the main body part  41 . The developer openings  48  are substantially rectangular in shape and are spaced at intervals in the left-to-right direction (one in the left-to-right center and one each on left and right ends). Thus, the developer openings  48  provide communication between the interior and exterior of the main body part  41 . 
     The developing device  12  is also provided with a developing shutter  44  for opening and closing the developer openings  48 . The developing shutter  44  has a partial cylindrical shape and is elongated in the front-to-rear direction. The left and right ends of the developing shutter  44  are rotatably supported in the retaining holes  43 . More specifically, the developing shutter  44  is integrally provided with a pair of left and right operating parts  38  and a cover part  49 . The operating parts  38  are rotatably fitted inside the corresponding retaining holes  43 . The cover part  49  has a curved plate shape and bridges the operating parts  38 . 
     The operating parts  38  are substantially disc-shaped and have a thickness nearly identical to the shutter support parts  42 . The first engaging parts  45  are formed in the left and right inner surfaces of the corresponding operating parts  38 . Each first engaging part  45  is a groove formed in the corresponding operating part  38  so as to extend diametrically through the center of the operating part  38 , spanning the entire diameter of the same. Second engaging parts  46  are formed on the left and right outer surfaces of the corresponding operating parts  38 . The second engaging parts  46  are ridge-like protrusions that extend through the center of the corresponding operating parts  38 , spanning the entire diameter of the same. The second engaging parts  46  overlap the first engaging parts  45  when the two are projected in the left-to-right direction. 
     The cover part  49  extends in the left-to-right direction and is formed in a curved plate shape that conforms to the curve in the front wall  47  of the developing device case  13 . The left and right edges of the cover part  49  are connected to the corresponding operating parts  38 . Hence, the cover part  49  moves together with the operating parts  38 . The cover part  49  is configured to cover the developer openings  48  when the first engaging parts  45  and second engaging parts  46  are oriented in the front-to-rear direction, as shown in  FIG. 2 . 
     The first engaging part  45  is rotated between a closed position (see  FIG. 7 ) in which the cover part  49  covers the front side of the developer openings  48 , and an open position (see  FIG. 9 ) in which the cover part  49  is separated from the developer openings  48 , thus exposing the same. 
     When the developing shutter  44  is in the closed position, the first engaging parts  45  are in communication with the corresponding guide parts  40 . 
     (2) Toner Cartridge 
     As shown in  FIGS. 3 and 4 , the toner cartridge  6  is provided with a cartridge case  51 . The cartridge case  51  is formed in the shape of three hollow cylindrical members aligned diametrically and joined together. 
     Specifically, the cartridge case  51  is integrally provided with a first peripheral wall  52  elongated in the left-to-right direction and having a C-shaped cross section opening rearward; a first arcing wall  53  that is arc-shaped in a cross section, with the convex side facing upward, and that is connected to the upper rear edge of the first peripheral wall  52 ; a second arcing wall  54  that is arc-shaped in a cross section, with the convex side facing downward, and that is connected to the lower rear edge of the first peripheral wall  52 ; and a second peripheral wall  55  that is C-shaped in a cross section and open toward the front, the diameter of the arc-shaped outer surface being substantially the same as the inner diameter of the front wall  47  constituting the developing device  12 , and that is connected to the rear edges of the first and second arcing walls  53  and  54 . The cartridge case  51  is also integrally provided with a pair of left and right side walls  56  for enclosing the space defined by the first peripheral wall  52 , first arcing wall  53 , and second arcing wall  54  from the left and right sides. 
     As shown in  FIG. 7 , a partitioning wall  58  is provided inside the cartridge case  51 . The partitioning wall  58  has an arcing plate shape and extends downward from the junction between the first peripheral wall  52  and first arcing wall  53  along the circumferential direction of the first arcing wall  53 . The left and right edges of the partitioning wall  58  are connected to the corresponding left and right side walls  56 . A gap is formed between the lower edge of the partitioning wall  58  and the junction between the first peripheral wall  52  and second arcing wall  54 . 
     The partitioning wall  58  partitions the space encompassed by the first peripheral wall  52  and the space defined by the first and second arcing walls  53  and  54  into a first toner accommodating section  59  and a second toner accommodating section  60 . The first and second toner accommodating sections  59  and  60  are in communication through the gap formed between the lower edge of the partitioning wall  58  and the junction between the first peripheral wall  52  and second arcing wall  54 . With the toner cartridge  6  according to the first embodiment, both the first toner accommodating section  59  and second toner accommodating section  60  are filled with toner and, hence, constitute the overall toner accommodating section. 
     An agitator  61  is provided inside the first toner accommodating section  59 . The agitator  61  includes an agitator shaft  62  that is rotatably held in the left and right side walls  56 , and an agitating film  63  supported on the agitator shaft  69 . 
     An agitator  64  is disposed in the second toner accommodating section  60 . The agitator  64  has an agitator shaft  65  rotatably held in the left and right side walls  56 , and an agitating film  66  supported on the agitator shaft  65 . 
     Three toner cartridge openings  68  are formed in the rear side of the second peripheral wall  55  in the circumferential center thereof. The toner cartridge openings  68  are substantially rectangular and spaced at intervals in the left-to-right direction at positions corresponding to the three developer openings  48  (see  FIG. 7 ). With this construction, the toner cartridge openings  68  are positioned in opposition to the developer openings  48  when the toner cartridge  6  is mounted in the drum cartridge  5 . 
     As shown in  FIGS. 4 and 7 , a cartridge shutter  71  having a partial cylindrical shape is rotatably provided inside the second peripheral wall  55 . The cartridge shutter  71  is elongated in the left-to-right direction and is rotatably supported in the second peripheral wall  55 , with the left and right endfaces of the cartridge shutter  71  exposed in the left and right ends of the second peripheral wall  55 . 
     Specifically, the cartridge shutter  71  is integrally provided with a pair of left and right operating parts  72  that are rotatably fitted inside the left and right ends of the second peripheral wall  55 , and a cover part  74  having a curved plate shape that spans between the operating parts  72 . 
     The operating parts  72  are substantially disc-shaped, and their outer left and right endfaces are substantially flush with the left and right ends of the second peripheral wall  55 . An engagement part  73  is formed on the outer surface of each of the left and right operating parts  72 . The first engagement parts  73  are ridge-like protrusions extending along a diameter of the operating parts  72  and can engage with the corresponding first engaging parts  45 . 
     The cover part  74  is elongated in the left-to-right direction and has a curved plate shape that conforms to the curve of the second peripheral wall  55 . The left and right edges of the cover part  74  are connected to the operating parts  72 . Thus, the cover part  74  can move together with the operating parts  72 . The cover part  74  is positioned so as to cover the toner cartridge openings  68  when the first engagement parts  73  are aligned in the front-to-rear direction. 
     Hence, the cartridge shutter  71  can be rotated between a first closed position (see  FIG. 7 ) in which the cover part  74  covers the toner cartridge openings  68  on the front side for restricting the discharge of toner, and a first open position (see  FIG. 9 ) in which the cover part  74  is retracted from the toner cartridge openings  68 , thus exposing the toner cartridge openings  68  and allowing the discharge of toner. 
     An auger  78  is provided inside the second peripheral wall  55 . The auger  78  has an auger shaft  79  aligned in the left-to-right direction and is rotatable about the auger shaft  79 . 
     As shown in  FIGS. 3 through 5 ( c ), the cartridge case  51  also has shutter operating units  57 , with one on each of the left and right sides of the second peripheral wall  55  and cartridge shutter  71 . The shutter operating units  57  are substantially disc-shaped and oppose the second peripheral wall  55  and cartridge shutter  71  in the left and right directions while separated therefrom. 
     The shutter operating units  57  have a larger diameter than that of the second peripheral wall  55  and are disposed so as to share the same central axis as the cartridge shutter  71 . Each shutter operating unit  57  includes an operating unit frame  80  that is substantially annular in shape, and an operating member  81  that is substantially disc-shaped. The operating member  81  is rotatably fitted inside the operating unit frame  80 . 
     The operating unit frame  80  is integrally configured of a receiving part  85  and a support part  86 . The receiving part  85  is arc-shaped in a cross-sectional view, opening rearward, and extends from the rear edge of the corresponding side wall  56  constituting the cartridge case  51  outward in the left-to-right direction. The support part  86  is substantially annular in shape and is formed continuously with the left and right outer edge of the receiving part  85 . 
     The inner periphery of the receiving part  85  has substantially the same curvature as the outer periphery of the front edge of the shutter support part  42  (see  FIG. 2 ) and is capable of receiving this front edge of the shutter support part  42 . The receiving part  85  also has a longer left-to-right dimension than that of the first engagement part  73 . 
     The support part  86  has an outer diameter substantially equivalent to that of the receiving part  85 . The front edge of the support part  86  is connected to the receiving part  85  so that the support part  86  protrudes rearward therefrom. A guide part  87  is formed in the rear edge of the support part  86  on the inner surface side with respect to the left-to-right direction. 
     The guide part  87  is a groove extending forward from the rear edge of the support part  86  along a radial to the same so as to pass radially from the outer side of the support part  86  to the inner side. The guide part  87  has a tapered shape, growing narrower toward the front. The width of the groove on the front edge of the guide part  87  is substantially equivalent to that of a second engagement part  83 . 
     The operating member  81  is provided with a fitting member  82  and an input member  84 . The fitting member  82  is substantially disc-shaped and is fitted inside the support part  86 . The input members  84  protrude outward in left and right directions from the corresponding outer left and right surfaces of the fitting members  82 . 
     Formed in each fitting member  82  are a second engagement part  83  (see  FIG. 3 ), and an input member accommodating part  88 . 
     The second engagement part  83  is a groove formed in the left or right inner surface of the corresponding fitting member  82  and extends diametrically through the center of the fitting member  82 , spanning the entire diameter thereof. 
     The input member accommodating part  88  is a groove cut out from the outer surface of the fitting member  82  inward in the left or right direction and extends along a diameter of the fitting member  82 . 
     The input member  84  is substantially rod-shaped, extending in a diametrical direction of the fitting member  82 , and is slidably fitted into the corresponding input member accommodating part  88  in the left-to-right direction. The input member  84  can be slid between a protruding position protruding outward in the left-to-right direction from the outer surface of the corresponding fitting member  82  (see  FIG. 5( a ) ), and a retracted position retracted inside the input member accommodating part  88  so that the outer surface in the left-to-right direction is substantially flush with the outer surface of the fitting member  82  (see  FIG. 5( b ) ). 
     As shown in  FIG. 5( c ) , compressed springs  89  are connected on one end to a bottom wall (inner wall with respect to the left-to-right direction) of the corresponding input member accommodating part  88  and on the other end to the inner side of the input member  84  with respect to the left-to-right direction. The compressed springs  89  constantly urge the input member  84  toward the protruding position. 
     When the fitting member  82  is rotated so that the input member  84  is aligned in the front-to-rear direction, as shown in  FIG. 3 , the second engagement part  83  and guide part  87  are in communication with each other. 
     (3) Mounting and Removing the Toner Cartridge Relative to the Drum Cartridge 
     Operations for mounting the toner cartridge  6  on and removing the toner cartridge  6  from the drum cartridge  5  will be described next with reference to  FIGS. 2 and 3 . 
     When the toner cartridge  6  is separated from the drum cartridge  5 , the developing shutter  44  of the drum cartridge  5  is in the closed position shown in  FIG. 2 . Thus, the cover part  49  of the developing shutter  44  confronts and closes the developer openings  48 . 
     Further, the cartridge shutter  71  is disposed in the first closed position and the operating members  81  of the toner cartridge  6  have been rotated so that the corresponding second engagement parts  83  and input members  84  are aligned in the front-to-rear direction, as shown in  FIGS. 3 and 4 . At this time, the cover part  74  of the cartridge shutter  71  opposes and closes the toner cartridge openings  68 . 
     The toner cartridge  6  is mounted on the drum cartridge  5  from the front side. Specifically, first the toner cartridge  6  is positioned in front of the drum cartridge  5 . Next, the drum cartridge  5  and toner cartridge  6  are placed at the same vertical position such that the first engagement parts  73  are aligned with the first engaging parts  45  and the second engagement parts  83  are aligned with the second engaging parts  46 . Subsequently, the toner cartridge  6  is assembled to the front of the drum cartridge  5  by inserting the shutter support parts  42  of the drum cartridge  5  between the cartridge shutter  71  and corresponding shutter operating units  57  of the toner cartridge  6 . 
     During this operation, the first engagement parts  73  are guided by the guide parts  40  into the first engaging parts  45 , while the second engaging parts  46  are guided by the guide parts  87  into the corresponding second engagement parts  83 . 
     At this time, the first engaging parts  45  of the drum cartridge  5  are engaged with the first engagement parts  73  of the toner cartridge  6 , while the second engaging parts  46  of the drum cartridge  5  are engaged with the second engagement parts  83  of the toner cartridge  6 . Accordingly, the operating members  81 , the developing shutter  44 , and the cartridge shutter  71  are rotatably interlocked. 
     When the front end of the second peripheral wall  55  contacts the cover part  49  of the developing shutter  44 , as shown in  FIG. 7 , the operation for mounting the toner cartridge  6  on the drum cartridge  5  is complete. 
     After the toner cartridge  6  has been completely mounted on the drum cartridge  5 , the operating members  81  oppose the corresponding cutout parts  36  in the drum frame  7  with respect to the left and right directions and are exposed outside the corresponding left and right cutout parts  36 , as shown in  FIG. 6 . 
     If the operating members  81  are rotated a prescribed angular distance counterclockwise in a left side view, as shown in  FIG. 8 , the developing shutter  44  of the drum cartridge  5  is rotated counterclockwise in a left side view into its open position, as illustrated in  FIG. 9 . When the developing shutter  44  is rotated in this way, the cover part  49  of the developing shutter  44  slides down below the developer openings  48 , thereby allowing communication between the developer openings  48  and the toner cartridge openings  68 . At the same time, the cartridge shutter  71  of the toner cartridge  6  is rotated counterclockwise in a left side view into its first open position. When the cartridge shutter  71  is rotated in this way, the cover part  74  of the cartridge shutter  71  slides down below the toner cartridge openings  68 , thereby opening the toner cartridge openings  68  and allowing communication between the toner cartridge  6  and developing device  12 . 
     4. Detailed Description of the Main Casing 
     As shown in  FIG. 10 , the main casing  2  includes guide grooves  100  for guiding the process cartridge  4  when the process cartridge  4  is mounted in or removed from the main casing  2 , and opening and closing mechanisms  101  for operating the operating members  81  to open and close the developing shutter  44 . 
     The guide grooves  100  are formed in the inner surfaces of the left and right side walls constituting the main casing  2 , with one guide groove  100  formed in each side wall. Each guide groove  100  is configured of a first guide groove  102 , and a second guide groove  103 . The first guide groove  102  begins from the front edge of the side wall and extends rearward in substantially a horizontal direction, but subsequently bends and follows a downward slope toward the rear end. The second guide groove  103  branches off the front end of the first guide groove  102  and slopes further downward toward the rear than the first guide groove  102 . 
     The first guide grooves  102  extend from the front edge of the main casing  2  to a position above the transfer roller  22  and function to receive and guide the drum shaft  11  of the photosensitive drum  8 . 
     The second guide grooves  103  lead to a position below the approximate front-to-rear center of the first guide grooves  102  and serve to receive and guide the input members  84  of the operating members  81 . 
     One of the opening and closing mechanisms  101  is provided in each of the left and right side walls of the main casing  2 . The opening and closing mechanisms  101  operate the operating members  81  in association with the opening and closing operation of the front cover  3 . 
     More specifically, each opening and closing mechanism  101  includes a rotating member  104  that is fitted onto the corresponding input member  84 , and a coupling member  105  for connecting the rotating member  104  to the front cover  3 . 
     The rotating member  104  is substantially circular in a side view and is rotatably embedded in the corresponding side wall of the main casing  2 . A fitting groove  99  is formed in the rotating member  104  for fitting the input member  84  therein. The fitting groove  99  extends along a diametrical direction of the rotating member  104  and spans the entire diameter of the same. 
     The rotating member  104  can be rotated between a first position (see  FIG. 10 ) in which the fitting groove  99  is in communication with the corresponding second guide groove  103 , and a second position (see  FIG. 11 ) rotated counterclockwise in a left side view a prescribed angular distance from the first position. 
     The coupling member  105  is substantially rod-shaped and aligned in the front-to-rear direction. The rear end of the coupling member  105  is connected to a peripheral edge portion of the rotating member  104 , while the front end is connected to the front cover  3 . A hinge part  108  is provided in a front-to-rear midpoint of the coupling member  105 , enabling the coupling member  105  to bend. 
     The front cover  3  is provided with coupling arms  106  that are substantially arc-shaped in a side view. A coupling hole  107  is formed in each coupling arms  106  and is elongated in an arc shape that follows the shape of the coupling arms  106 . The front ends of the coupling members  105  are coupled in the coupling holes  107  of the corresponding coupling arms  106  and are capable of sliding within the coupling holes  107 . 
     When the front cover  3  is in its open state, the front ends of the coupling members  105  are positioned in the rearmost ends of the coupling holes  107 . By opening the front cover  3  in this way, the rotating members  104  are moved to their first position by the coupling members  105 . 
     When the front cover  3  is closed, the front ends of the coupling members  105  slide to the front ends of the coupling holes  107  as the front cover  3  rotates. When the front ends of the coupling members  105  reach the front ends of the coupling holes  107 , the front cover  3  is still slightly open, as indicated by the broken lines in  FIG. 10 . 
     When the operator pushes the front cover  3  completely closed, as shown in  FIG. 11 , the coupling arms  106  press the front ends of the coupling members  105  rearward, forcing the coupling members  105  to move rearward while rotating the rotating members  104  counterclockwise in a left side view. Thus, the rotating members  104  are moved to their second position. 
     5. Mounting and Removing the Process Cartridge Relative to the Main Casing 
     As shown in  FIG. 12 , the process cartridge  4  is mounted in the main casing  2  while the front cover  3  is in its open state. To mount the process cartridge  4  into the main casing  2 , both ends of the drum shaft  11  in the photosensitive drum  8  are inserted into the corresponding first guide grooves  102 , and the process cartridge  4  is pushed rearward. As the process cartridge  4  moves rearward, both ends of the drum shaft  11  are guided in the first guide grooves  102 . 
     At the point the rear half of the process cartridge  4  has been inserted into the main casing  2  and the operating members  81  are beginning to advance into the main casing  2 , the input members  84  of the operating members  81  enter the corresponding second guide grooves  103 . 
     As the process cartridge  4  continues to move rearward, the ends of the drum shaft  11  are guided in the first guide grooves  102  while the input members  84  on the operating members  81  are guided in the second guide grooves  103 . As a result, the process cartridge  4  moves along a downward slope toward the rear. 
     When the ends of the drum shaft  11  arrive at the rear ends of the first guide grooves  102 , the process cartridge  4  is completely mounted in the main casing  2  and the input members  84  of the operating members  81  are fitted into the fitting grooves  99  of the rotating members  104 . When the front cover  3  is closed after the process cartridge  4  has been completely mounted in this way, the coupling members  105  of the opening and closing mechanisms  101  move rearward, rotating the rotating members  104 , as described above. As the rotating members  104  are rotated, the operating members  81  also rotate a prescribed angular distance counterclockwise in a left side view. 
     As described above, in association with this rotation of the operating members  81 , the developing shutter  44  is moved from the closed position to the open position, and the cartridge shutter  71  is moved from the first closed position to the first open position. As a result, the toner cartridge  6  is now in communication with the developing device  12 . 
     In order to remove the process cartridge  4  from the main casing  2 , the procedure for mounting the process cartridge  4  described above is performed in reverse. That is, first the operator opens the front cover  3 , causing the coupling arms  106  of the front cover  3  to pull the coupling members  105  forward. This movement of the coupling members  105  then rotates the operating members  81  a prescribed angular distance clockwise in a left side view. 
     In association with the movement of the operating members  81 , the developing shutter  44  is moved from the open position to the closed position, and the cartridge shutter  71  is moved from the first open position to the first closed position. As a result, the cover part  49  of the developing shutter  44  closes the developer openings  48 , and the cover part  74  of the cartridge shutter  71  closes the toner cartridge openings  68 . 
     Further, the rotating members  104  are in the first position at this time, allowing communication between the fitting grooves  99  and corresponding second guide grooves  103 . Thereafter, the operator can pull the process cartridge  4  forward from the main casing  2  and extract the process cartridge  4  therefrom. 
     6. Toner Agitation and Circulation 
     Next, the processes for agitating and circulating toner in the process cartridge  4  will be described with reference to  FIG. 9 . 
     When the process cartridge  4  is mounted in the main casing  2 , a drive force from a drive mechanism (not shown) rotates the agitators  61  and  64  and the augers  16  and  78 . 
     The agitator  61  rotates clockwise in a left side view. By rotating, the agitator  61  agitates toner in the first toner accommodating section  59 , while supplying some of the toner to the second toner accommodating section  60  through the gap between the bottom edge of the partitioning wall  58  and the junction between the first peripheral wall  52  and second arcing wall  54 . 
     The agitator  64  rotates counterclockwise in a left side view. By rotating the agitator  64  agitates toner in the second toner accommodating section  60 , while supplying some of the toner to the second peripheral wall  55 . The rotating agitator  64  also returns some of the toner to the first toner accommodating section  59  through the gap between the bottom edge of the partitioning wall  58  and the junction between the first peripheral wall  52  and second arcing wall  54 . In this way, toner is circulated between the first and second toner accommodating sections  59  and  60 . 
     The rotating auger  78  conveys toner in the second peripheral wall  55  toward the left-to-right center of the same, discharging some of the toner from the toner cartridge  6  through the center toner cartridge opening  68  and supplying the toner into the developing device case  13  through the center developer opening  48 . Here, toner in the second peripheral wall  55  has a level L 1  (indicated by the broken line in  FIG. 9 ) higher than the bottom edge of the toner cartridge openings  68 , and the toner cartridge opening  68  is formed on the rear side of the toner cartridge  6  to enable the discharge of toner from the same. In other words, the toner cartridge opening  68  allows the toner to discharge outside from the cartridge when at least part of an opening edge of the toner cartridge opening  68  is positioned at a position lower than a level of the toner accommodated in the toner cartridge  6 . 
     In the meantime, the auger  16  provided on the developing device case  13  side rotates to convey toner supplied into the developing device case  13  out from the center of the developing device case  13  in the left and right directions, returning some of the toner into the toner cartridge  6  through the left and right developer openings  48  and toner cartridge openings  68 . 
     Through this process, toner is agitated in the toner cartridge  6  and circulated between the toner cartridge  6  and developing device case  13 . 
     7. Packaging for a Laser Printer 
     (1) Toner Cartridge Cover 
     When shipping the laser printer  1  of the preferred embodiment, rather than packaging the process cartridge  4  and main casing  2  separately, the laser printer  1  is packaged with the process cartridge  4  accommodated in the main casing  2 . 
     Before mounting the process cartridge  4  in the main casing  2  in this case, a toner cartridge cover  111  shown in  FIG. 13  is mounted on the process cartridge  4  in order to cover both left and right operating members  81  of the toner cartridge  6  (see  FIG. 3 ). 
     The toner cartridge cover  111  is formed of a flexible material, such as a resin. The toner cartridge cover  111  is substantially cylindrical in shape and is elongated in the left-to-right direction, the direction being based on the toner cartridge cover  111  mounted on the process cartridge  4 . Both left and right ends  111 A of the cylindrically shaped toner cartridge cover  111  are closed. The left-to-right length of the toner cartridge cover  111  is substantially equivalent to the left-to-right dimension of the toner cartridge  6  at the rear end thereof (specifically, the distance between the left endface of the left fitting member  82  and the right endface of the right fitting member  82 . The inner diameter of the toner cartridge cover  111  is greater than the outer diameter of the shutter operating unit  57 . 
     A developing device side opening  113  is formed in the circumferential surface of the toner cartridge cover  111  on one side relative to a radial direction of the toner cartridge cover  111  for receiving the front end of the developing device  12 . A toner cartridge side opening  112  is formed in the circumferential surface of the toner cartridge cover  111  on the opposite side from the developing device side opening  113  for receiving the second peripheral wall  55  and the front end of the second toner accommodating section  60  constituting the toner cartridge  6 . 
     The developing device side opening  113  has a substantially rectangular shape, with a left-to-right dimension greater than the left-to-right dimension of the developing device  12  (specifically, the distance between the left edge of the left shutter support part  42  and the right edge of the right shutter support part  42 ). 
     The toner cartridge side opening  112  is also substantially rectangular in shape, with substantially the same left-to-right dimension as the developing device side opening  113  and a vertical dimension sufficient to receive the front end of the second toner accommodating section  60 . 
     (2) Inserting the Process Cartridge in the Main Casing 
     In order to place the process cartridge  4  in the main casing  2 , first the toner cartridge cover  111  is mounted on the toner cartridge  6  with the cartridge shutter  71  disposed in the first closed position, as shown in  FIG. 14( a ) . 
     In order to mount the toner cartridge cover  111  on the toner cartridge  6 , the operator stretches both left and right ends  111 A of the toner cartridge cover  111  on the front side outward in left and right directions so as to widen the left-to-right dimension of the toner cartridge side opening  112 . Subsequently, the operator places the toner cartridge cover  111  over the rear end of the toner cartridge  6  from the rear side thereof. 
     Next, the operator releases the left and right ends  111 A of the toner cartridge cover  111  so that the shutter operating units  57  remain accommodated inside the left and right ends  111 A of the toner cartridge cover  111 . As a result, the left and right ends  111 A of the toner cartridge cover  111  return to their original shape and remain fitted around the outer left and right sides of the respective shutter operating units  57 . 
     As shown in  FIG. 14( b ) , the left and right ends  111 A of the toner cartridge cover  111  press the input members  84  of the corresponding shutter operating units  57  inward in left and right directions, pushing the input members  84  into their retracted positions inside the input member accommodating parts  88 . Consequently, the toner cartridge cover  111  restricts operations of the input members  84 . 
     Next, before inserting the process cartridge  4  into the main casing  2 , a masking tape  121  is applied to the toner cartridge  6 , as shown in  FIG. 15 . The masking tape  121  is a long strip of tape. One end of the masking tape  121  is applied to the upper edge of the second peripheral wall  55  constituting the toner cartridge  6  near the left side. A marker  122  is provided on the other end of the masking tape  121 . The marker  122  has a substantially rectangular plate shape. 
     Next, the toner cartridge  6  is mounted in the drum cartridge  5  while the toner cartridge cover  111  and masking tape  121  remain attached thereto. As described above, in order to mount the toner cartridge  6  on the drum cartridge  5 , the toner cartridge  6  is assembled to the front of the drum cartridge  5  such that the shutter support parts  42  are inserted between the operating parts  72  of the cartridge shutter  71  and respective shutter operating units  57  of the toner cartridge  6 . 
     Through this operation, the shutter support parts  42  are inserted through the developing device side opening  113  formed in the toner cartridge cover  111  and between the cartridge shutter  71  and shutter operating units  57  of the toner cartridge  6 . Hence, the toner cartridge  6  is mounted on the drum cartridge  5  while the toner cartridge cover  111  and masking tape  121  remain attached to the toner cartridge  6 . 
     At this time, the left and right ends  111 A of the toner cartridge cover  111  confront the cutout parts  36  formed in the drum frame  7  and are exposed outside the cutout parts  36  on both left and right sides. 
     Next, the process for inserting the process cartridge  4  into the main casing  2  will be described with reference to  FIG. 16 . In order to mount the process cartridge  4  in the main casing  2 , first the front cover  3  is opened, as described above. Next, the ends of the drum shaft  11  in the photosensitive drum  8  are inserted into the respective first guide grooves  102 , and the process cartridge  4  is pushed rearward until the ends of the drum shaft  11  reach the rear ends of the first guide grooves  102 . 
     The process cartridge  4  is completely mounted in the main casing  2  when the ends of the drum shaft  11  reach the rear ends of the first guide grooves  102 . At this time, the left and right ends  111 A of the toner cartridge cover  111  confront the corresponding left and right fitting grooves  99  of the rotating members  104  from the inside thereof. 
     Consequently, the toner cartridge cover  111  prevents the input members  84  of the operating members  81  from being fitted into the fitting grooves  99  of the rotating members  104 , interrupting the associative movement between the front cover  3  and operating members  81 . In this way, the developing shutter  44  is held in its closed position while the cartridge shutter  71  is held in its first closed position. 
     Before closing the front cover  3 , the free end of the masking tape  121  is drawn out through the access opening  17  formed in the main casing  2 , and a cushioning member  123  is inserted through the access opening  17 . The front cover  3  is then closed so that the cushioning member  123  is positioned between the front cover  3  and process cartridge  4 , and the free end of the masking tape  121  remains outside the main casing  2 . Next, the marker  122  of the masking tape  121  is affixed to the bottom surface of the laser printer  1  on the left side thereof. Through this operation, the process cartridge  4  is now completely accommodated in the main casing  2 , as shown in  FIG. 16 . 
     (3) Packaging for a Laser Printer 
     (3-1) Packaging Member 
     The laser printer  1  is packed into a packaging member  124 , after the process cartridge  4  has been inserted in the main casing  2  according to the method described above. 
     As shown in  FIGS. 17( a ), 17( b ), and 18( a ) , the packaging member  124  includes a packing box  125 , a bottom cushioning member  126 , and a top cushioning member  127 . 
     The packing box  125  is formed of a thick paper, such as corrugated cardboard, and is configured in a box shape that is elongated vertically. The bottom surface has a smaller surface area than each side surface. In other words, the footprint of the packing box  125  is smaller than the footprint required if the packing box  125  were laid on its side. 
     The bottom cushioning member  126  is formed of Styrofoam or another material and is roughly block-shaped with a depression in the top surface formed to receive the front end of the laser printer  1 . Note that the bottom cushioning member  126  has horizontal outer dimensions corresponding to the horizontal inner dimensions of the packing box  125 , so that the bottom cushioning member  126  does not move around in the packing box  125  during transit. The bottom cushioning member  126  is placed in the bottom of the packing box  125  for packaging the laser printer  1 . 
     As with the bottom cushioning member  126 , the top cushioning member  127  is formed of Styrofoam or a similar material and is roughly block-shaped with a depression in the bottom surface formed to receive the rear end of the laser printer  1 . The horizontal outer dimensions of the top cushioning member  127  correspond to the horizontal inner dimensions of the packing box  125 . The packaging box  125  has a bottom surface  125 A and a side surface  125 B whose dimension is greater than a dimension of the bottom surface  125 A. 
     (3-2) Packaging the Laser Printer 
     When packing the laser printer  1 , first the top end of the packing box  125  is opened, and the laser printer  1  is positioned above the opening in the packing box  125 , with the rear end of the laser printer  1  facing upward, as shown in  FIG. 18( a ) . Next, the laser printer  1  is inserted front end first into the packing box  125 , and the front end of the laser printer  1  is fitted into the depression formed in the bottom cushioning member  126 . The bottom surface  125 A faces an installation surface when the packaging member is installed on the installation surface. 
     Next, the top cushioning member  127  is placed over the top of the laser printer  1  so that the rear end of the laser printer  1  is fitted into the depression formed in the top cushioning member  127 , as shown in  FIG. 18( b ) . Lastly, the top end of the packing box  125  is closed, as shown in  FIG. 18( c ) . This completes the process for packing the laser printer  1  in the packaging member  124 . The resulting packaging unit  1000  includes the vertically oriented laser printer  1  packed inside the packaging member  124 . Consequently, the rear end of the laser printer  1  faces upward while packed in the packaging member  124 . Hence, the toner cartridge openings  68  formed in the rear end of the toner cartridge  6  (see  FIG. 15 ) are arranged on the top end of the toner cartridge  6  when the laser printer  1  is in a packaged state and, therefore, face upward, unlike when the laser printer  1  is in an operational state (see  FIG. 11 ) and the toner cartridge openings  68  face rearward. In other words, the color laser  1  is packaged in the packaging member  124  in such a posture that the toner cartridge  6  is in a second posture (see  FIG. 18 ) where leakage of the toner from the cartridge opening  68  is unlikely to occur as compared with a posture of the color laser  1  in which the toner cartridge  68  is in a first posture (see  FIG. 7 ). Further, the cartridge opening  68  is in a predetermined position (see  FIG. 7 ) when an image is formed, and is in a developer-leakage preventing position angularly offset from the predetermined position when the toner cartridge  6  is in the second posture (see  FIG. 18 ). The developer-leakage preventing position can be set to fall within a prescribed angular range determined depending upon the predetermined position. In this embodiment, the toner cartridge  6  opens diagonally downward when the cartridge opening  68  is in the predetermined position as shown in  FIG. 7  and opens upward when the cartridge opening  68  is in the developer-leakage preventing position as shown in  FIG. 19 . 
     In this way, the toner cartridge openings  68  are positioned above the first toner accommodating section  59  and second toner accommodating section  60  and are also above a level L 2  of toner in the toner cartridge  6  (see  FIG. 19 ), ensuring that toner is not discharged through the toner cartridge openings  68 . In other words, the laser printer  1  is packaged in the packaging member  12  in such a posture that the entire opening edge of the toner cartridge openings  68  is positioned at a position higher than the level of the toner accommodated in the toner cartridge  6 . 
     The developing roller  14  supported in the rear end of the developing device  12  is positioned at the top end of the developing device  12  when the laser printer  1  is in a packaged state. Thus, the developing roller  14  is positioned higher than the developer openings  48  and toner cartridge openings  68 . 
     8. Installing the Laser Printer 
     In order to unpack the laser printer  1  for usage, the top of the packaging member  124  is opened, and the laser printer  1  is extracted from the packaging member  124 . The laser printer  1  is then placed on a level installation surface with the discharge tray  25  facing upward. 
     At this time, the marker  122  is interposed between the bottom edge of the laser printer  1  and the installation surface, preventing the laser printer  1  from lying in a stable, level orientation. In order to place the laser printer  1  in a stable, level orientation, the operator removes the marker  122  from the bottom of the laser printer  1 . Subsequently, the operator rotates the front cover  3  forward into the second open position, exposing the access opening  17 . 
     Next, the user pulls the process cartridge  4  out of the main casing  2  through the access opening  17 . After removing the process cartridge  4 , the user peels off the masking tape  121  from the process cartridge  4  and removes the toner cartridge cover  111 . The latter is removed by pulling the left and right ends  111 A of the toner cartridge cover  111  outward in left and right directions, thereby widening the toner cartridge side opening  112  so that the toner cartridge cover  111  can be pulled off the shutter operating units  57  and removed from the toner cartridge  6 . 
     After having removed the masking tape  121  and toner cartridge cover  111  from the toner cartridge  6 , the toner cartridge  6  is remounted in the main casing  2  according to the process described earlier, and the front cover  3  is closed. At this time, the laser printer  1  is ready to use. Further, the toner cartridge openings  68  formed in the toner cartridge  6  now face rearward, and the level L 1  of toner accommodated in the toner cartridge  6  (see  FIG. 9 ) is higher than the lower edges  68 A of the toner cartridge openings  68 . 
     9. Operations and Effects 
     (1) With the package and the method of packaging the laser printer  1  according to the present invention, the laser printer  1  is packaged with its rear end facing upward, while the toner cartridge  6  is accommodated inside the laser printer  1 , as shown in  FIG. 18 . In this way, the toner cartridge openings  68  formed in the toner cartridge  6  face upward and are higher than a position at which toner could be discharged from the toner cartridge  6 . 
     Accordingly, rather than increasing the number of boxes required for packaging, this method reduces the size of the box used for packaging by an amount saved by accommodating the toner cartridge in the body of the printer. 
     Since the printer is transported with the toner cartridge accommodated in the body thereof, vibrations and other disturbances applied to the packaged printer during transport and the like may cause toner to leak from the cartridge and contaminate the printer in some cases. 
     However, with the laser printer  1  oriented with its rear end facing upward, the toner remains settled in the toner cartridge  6  by its own weight despite vibrations or other disturbances that may be applied to the laser printer  1  during transport. As a result, this method prevents toner from leaking into the laser printer  1  when the laser printer  1  is packaged with the toner cartridge  6  accommodated therein. 
     (2) Further, when the laser printer  1  is packaged according to the package and packaging method of the present invention, the cartridge shutter  71  is disposed in the first closed position shown in  FIG. 7 . Hence, the cartridge shutter  71  can restrict toner from leaking out of the toner cartridge openings  68 . Accordingly, this construction reliably prevents toner from leaking into the laser printer  1 . 
     (3) When the laser printer  1  is packaged according to the package and packaging method of the present invention, the process cartridge  4  is inserted into the main casing  2  with the toner cartridge cover  111  attached thereto. The toner cartridge cover  111  interferes with the input members  84  of the toner cartridge  6  so that the cartridge shutter  71  is maintained in the first closed position. 
     Accordingly, the cartridge shutter  71  can be maintained in the first closed position, even when the packaged laser printer  1  is subjected to vibrations or other disturbances, thereby reliably preventing toner from leaking into the laser printer  1 . 
     (4) When the laser printer  1  is packaged according to the package and packaging method of the present invention, the developing roller  14  is arranged above the toner cartridge openings  68  and developer openings  48 , as shown in  FIG. 19 . 
     Therefore, even if the user were to package a used laser printer  1  to be sent for repairs, for example, the laser printer  1  would be packaged so that no toner is present near the developing roller  14 . This configuration suppresses toner that may have become deposited on sealing parts or the like provided near the developing roller  14  from falling inside the laser printer  1 . 
     (5) With the package and the packaging method for the laser printer  1  according to the present invention, the footprint of the packing box  125  is smaller than the footprint of the packing box  125  when laid on its side (i.e., when the packing box is placed in the same orientation as the laser printer  1  in its operational state), as shown in  FIG. 17 . Hence, packaged laser printers  1  can be stored with better space savings. 
     (6) When the laser printer  1  is packaged according to the package and packaging method of the present invention with the developing unit (i.e., the toner cartridge  6  and developing device  12 ) accommodated in the main casing  2 , the level L 2  of toner in the toner cartridge  6  is lower than the bottom edges  68 A of the toner cartridge openings  68 , as shown in  FIG. 19 . This arrangement further prevents toner from leaking into the laser printer  1 . 
     10. Variations of the Embodiment 
     In the first embodiment described above, the compressed springs  89  are provided between the bottom wall (inner wall in the left-to-right direction) of the input member accommodating parts  88  and the inner side of the corresponding input members  84  with respect to the left-to-right direction. However, a leaf spring, sponge, or the like may be used in place of the compressed springs  89 . 
     Further, when the laser printer  1  is arranged in its operational state in the first embodiment, the toner cartridge openings  68  formed in the toner cartridge  6  face rearward. However, as shown in  FIGS. 20-24 , a laser printer  141  according to a second embodiment of the present invention may be provided with a toner cartridge  142  having toner cartridge openings  143 . According to the second embodiment, the toner cartridge openings  143  face downward when the laser printer  141  is arranged in its operational state. 
     More specifically, the toner cartridge  142  has a cartridge case  151  that is mounted on and removed from the drum cartridge  5  vertically. The cartridge case  151  has a substantially hollow cylindrical shape and accommodates toner. The toner cartridge openings  143  are formed in the bottom portion of the cartridge case  151 , penetrating the peripheral wall of the same. 
     A cartridge shutter  144  is also provided on the toner cartridge  142  for opening and closing the toner cartridge openings  143 . The cartridge shutter  144  includes a cover member  148 , and a pair of left and right arms  149 . 
     The cover member  148  is formed in a curved plate shape elongated in the left-to-right direction. The curve of the cover member  148  conforms to the peripheral surface of the cartridge case  151 . 
     Each of the arms  149  is substantially rod-shaped and extends vertically. The arms  149  are rotatably connected to the left and right sides of the cartridge case  151  via connecting parts  152  provided one in substantially the vertical center of each arm  149 . The bottom ends of the arms  149  are connected to the respective left and right ends of the cover member  148 . A substantially rod-shaped grip  153  extending in the left-to-right direction bridges the top ends of the arms  149  for coupling the same. 
     In addition, the portions of the arms  149  above the connecting parts  152  are capable of bending at hinge parts  150 . The portion of the arms  149  above the hinge parts  150  move between a horizontal position (see  FIG. 23 ) rotated forward about the hinge part  150  to approximately the horizontal, and an erect position (see  FIG. 22 ) erected so the entire arms  149  extend substantially linearly. 
     With the arms  149  in their erect state, the cartridge shutter  144  rotates about the connecting parts  152  between a first closed position (see  FIG. 22 ) at which the cover member  148  covers the toner cartridge openings  143  from the bottom, and a first open position (see  FIG. 20 ) at which the cover member  148  does not cover the toner cartridge openings  143 . 
     An access opening  145  is formed in the top of the main casing  2  near the front side thereof. A cover  146  is rotatably provided on the top of the main casing  2  and is capable of pivoting between a second closed position (see  FIG. 20 ) for covering the access opening  145 , and a second open position (see  FIG. 21 ) for exposing the access opening  145 . 
     After installing the laser printer  141  in a level state and mounting the toner cartridge  142  on the drum cartridge  5 , the laser printer  141  can be operated when the cartridge shutter  144  is disposed in the first open position. When the cartridge shutter  144  is in the first open position, toner accommodated in the toner cartridge  142  is discharged downward through the toner cartridge openings  143  and supplied into the developing device  12 . 
     In order to package the laser printer  141 , the toner cartridge  142  is first mounted inside the main casing  2 . This is achieved by opening the cover  146  to expose the access opening  145 , as shown in  FIG. 21 , and by inserting the toner cartridge  142  downward through the access opening  145  into the main casing  2 , as illustrated in  FIG. 22 . 
     At this time, the portion of the arms  149  above the corresponding hinge parts  150  are in the erect position, protruding above the access opening  145 . Accordingly, even if the user were to attempt to rotate the cover  146  into the second closed position, the cover  146  would halt before reaching the second position when contacting the top ends of the arms  149 , as indicated by the broken line in  FIG. 22 . 
     As shown in  FIG. 23 , the portions of the arms  149  above the corresponding hinge parts  150  have been bent forward into the horizontal position and are accommodated inside the main casing  2 , rather than protruding out of the access opening  145 . Thereafter, the cover  146  can be rotated into its second closed position, thereby completing the operation to mount the toner cartridge  142  in the main casing  2 . Note that the toner cartridge  142  is accommodated in the main casing  2  while the cartridge shutter  144  is maintained in its first closed position. 
     When packing the laser printer  141 , the laser printer  141  is packed into a packing box  147  with its bottom end facing upward, as shown in  FIG. 24 . With this method, the toner cartridge openings  143  formed in the bottom of the toner cartridge  142  and facing downward when the laser printer  141  is in its operational state are disposed on the top of the toner cartridge  142  facing upward when the laser printer  141  is in the packaged state. Accordingly, the toner cartridge openings  143  are positioned higher than a level L 3  of toner accommodated in the toner cartridge  142 . 
     In order to unpack the laser printer  141  for usage, the laser printer  141  is extracted from the packing box  147  and placed on a level installation surface. Next, the user opens the cover  146  and bends the top portions of the arms  149  back to their erect position. Subsequently, the user extracts the toner cartridge  142  from the main casing  2 , and the opening and closing operations of the cartridge shutter  144  are enabled. 
     Next, the user remounts the toner cartridge  142  in the main casing  2 . At this time, when the arms  149  are in their erected state and the cartridge shutter  144  is in its first closed position, the arms  149  protrude out of the main casing  2  through the access opening  145 , preventing the cover  146  from being closed, as described above. 
     Hence, the user will notice that the cartridge shutter  144  is still in its first closed position. Upon noticing that the cartridge shutter  144  is in its first closed position, the user presses the arms  149  rearward, rotating the cartridge shutter  144  counterclockwise in a left side view about the connecting parts  152  and shifting the cartridge shutter  144  from its first closed position to its first open position. Consequently, the arms  149  are accommodated in the main casing  2  rather than protruding out through the access opening  145 , enabling the user to close the cover  146 . 
     At this time, the toner cartridge openings  143  are open, and toner is discharged downward through the toner cartridge openings  143 . Hence, the laser printer  141  is now operational. 
     While the invention has been described in detail with reference to the embodiments 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. 
     For example, when packaging the laser printer  141  in the packing box  147 , the laser printer  141  can be tilted with its bottom edge facing upward at an angle, as illustrated in  FIG. 25 . In this case, the toner cartridge openings  143  formed in the bottom of the toner cartridge  142  and facing downward when the laser printer  141  is in its operational state are facing diagonally upward when the laser printer  141  is in the packaged state and are positioned above a level L 4  of toner accommodated in the toner cartridge  142 .