Abstract:
An image forming apparatus, such as a printer, may have a horizontally-loaded drawer containing, for example, a toner cartridge or an image forming unit having toner. The apparatus may have an opening through which the drawer is inserted, and a cover over the opening. The cover may include two or more protrusions to assist in forcing the drawer into place as the cover is closed. The cover may include a first protrusion that is closer to the cover&#39;s hinge, and a second that is farther from the hinge than the first. The first protrusion may also be longer, extending further from the cover, than the second, so that during the closing operation, the first protrusion makes contact with the drawer before the second. The points of contact on the drawer may be angled and/or curved such that the force exerted by the protrusions directs the drawer horizontally and, if desired, downwardly towards an operating position. A protrusion may be aligned such that, when the cover is in the closed position, the protrusion is offset from a point of contact on the drawer, and exerts no horizontal force on the drawer.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority from Japanese Patent Application No. 2006-318677, filed on Nov. 27, 2006, the entire subject matter of which is incorporated herein by reference. 
   TECHNICAL FIELD 
   Aspects described herein relate to an image forming apparatus, such as a laser printer. 
   BACKGROUND 
   Electrophotographic image forming apparatuses such as laser printers are generally configured to form an image on a recording medium such as a sheet of paper or a transparency (hereinafter referred to as a recording sheet) by transferring a developing agent or toner. However, toner is consumable and needs replenishing regularly. 
   In some of the image forming apparatuses, a process cartridge (e.g., an image forming unit), which includes a toner storing portion configured to store toner therein, is disposed in an apparatus body so as to be vertically removable. When toner decreases, the process cartridge is replaced with a new one. 
   When a process cartridge is installed in the apparatus body, the process cartridge is inserted, from above, down into the apparatus body and a cover is closed. A lever member is configured to mechanically move along with a closing movement of the cover. The lever member presses the process cartridge downward and moves it to its normal position. 
   SUMMARY 
   Aspects described herein may provide an image forming apparatus configured to move an image forming unit, which is horizontally and movably coupled to the image forming apparatus, to a normal position in association with a closing operation of a cover. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Features herein will be described in detail with reference to the following figures in which like elements are labeled with like numbers and in which: 
       FIG. 1  is a side sectional view showing a main part of a laser printer according to an illustrative embodiment; 
       FIG. 2  is a side sectional view of a drawer unit being attached to or removed from the laser printer; 
       FIG. 3  is a side sectional view of a drawer unit being attached to or removed from the laser printer; 
       FIG. 4  is a side sectional view of a drawer unit being attached to or removed from the laser printer; 
       FIG. 5  is an enlarged view of a part enclosed by A of  FIG. 4 ; 
       FIG. 6  illustrates force acting on a cover and the drawer unit; and 
       FIG. 7  is a schematic view showing feature of a second embodiment. 
   

   DETAILED DESCRIPTION 
   The following section is made with reference to the accompanying drawings. 
   The image forming apparatus features described herein may be applied to an electrophotographic image forming apparatus, such as a laser printer. It will be appreciated that aspects of the invention apply to other types of image forming apparatuses as well. 
   For purposes herein, aspects of the invention are shown in relation to an image carrier and developer carrier. In various aspects, the image carrier may include a photosensitive drum, photosensitive belt, or the combination of one of a photosensitive drum or belt and an intermediate transfer drum or belt. Further, the developer carrier may include a developer roller or other systems for conveying developer to the image carrier. 
   It is noted that various connections are set forth between elements in the following description. It is noted that these connections in general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. 
   An appearance of a laser printer  1  will be now described with reference to  FIGS. 1-5 . 
   An upper side of  FIG. 1  is referred to as the top of a laser printer  1 , and the right side of  FIG. 1  is referred to as the front side of the laser printer  1 . In the following description, top, bottom, rear, and front of objects in the laser printer  1  are used with reference to the arrows in  FIG. 1 . 
   A housing  3  provides for an apparatus body of the laser printer  1 . A sheet discharge tray  5  may be provided on the top of the housing  3 . Printed recording sheets such as plain paper or transparency may be ejected from the housing  3  and received on the sheet discharge tray  5 . 
   As shown in  FIGS. 2-4 , an opening  3 A may be provided on the front side of the housing  3 . The opening  3 A may be opened and closed by a front cover  100  pivotally coupled to a lower end of the housing  3  via a hinge mechanism  110  as shown in  FIG. 1 . 
   The hinge mechanism  110  may be provided with slots formed on the front cover  100  and the housing  3 , pins inserted into the slots, and substantially L-shaped spring plates (not shown) that draw the pins to the housing  3  or the front cover  100 . The slots respectively formed on the housing  3  and the front cover  100  may be disposed substantially perpendicularly to each other when the front cover  100  is closed as shown in  FIG. 1 . 
   A frame member (not shown) made of metal or resin may be provided in the housing  3 , and a drawer unit  70  and a fixing unit  80  may be coupled to the frame member in a detachable manner. 
   An internal structure of the laser printer  1  will be described. 
   The laser printer  1  may include an image forming portion  10 , a feeder portion  20 , and a feed mechanism  30 . The image forming portion  10  functions as an image forming device that is configured to form an image onto a recording sheet. The feeder portion  20  may function as a part of a feeding device configured to supply a recording sheet to the image forming portion  10 . The feed mechanism  30  may be configured to feed a recording sheet to four image forming units  70 K,  70 Y,  70 M,  70 C that make up the image forming portion  10 . 
   After an image has been recorded on the recording sheet, an intermediate feed roller  90  and an ejection chute (not shown) may take the recording sheet and feed it upwards towards ejection rollers  91 . The ejection rollers  91  may cause the sheet to be ejected from the ejection portion  7  and onto the ejection tray  5 . 
   The feeder portion  20  may include a sheet supply tray  21 , a sheet supply roller  22 , and a separation pad  23 . The sheet supply tray  21  may be disposed in the lowermost part of the housing  3 , and may be configured to hold a stack of recording sheets. The sheet supply roller  22  may be disposed at an upper front end of the sheet supply tray  21 , and may be configured to supply or feed a recording sheet from the sheet supply tray  21  to the image forming portion  10 . The separation pad  23  may be disposed downstream of the sheet supply roller  22  in the direction of the roller&#39;s rotation, and may be configured to apply a resistance to separate a topmost sheet from the stack of recording sheets in the sheet supply tray  21 . 
   The recording sheet stored in the sheet supply tray  21  makes a u-turn (e.g., is flipped over) at the front side of the housing  3 , and fed to the image forming portion  10 , which may be centrally disposed in the housing  3 . A feed roller  24  may be disposed where the u-turn is made, and may be located along a sheet feed path extending from the sheet supply tray  21  to the image forming portion  10 . The feed roller  24  may be configured to give a feeding force to a recording sheet being fed to the image forming portion  10  while the sheet makes its u-turn. 
   A pressure roller  25  may be disposed facing the feed roller  24 . The pressure roller  25  may be configured to press a recording sheet toward the feed roller  24 . The pressure roller  25  may be urged toward the feed roller  24  by an elastic member such as a coil spring (not shown). 
   A feed chute  26  is disposed downstream of the feed roller  24  with respect to a direction where a recording sheet is fed (hereinafter referred to as a sheet feeding direction). The feed chute  26  functions as a guiding device that guides a recording sheet by contact with an outer surface of the recording sheet being fed in a u-shape. A pressure roller  27  is disposed on an inner side of the feed path bent in a u-shape. The pressure roller  27  is configured to press the recording sheet being fed toward the feed chute  26 . 
   In one example embodiment, the feed chute  26  may be integrally formed with the front cover  100  while the pressure roller  27 , the feed roller  24  and the pressure roller  25  are coupled to the housing  3 . 
   The feed mechanism  30  may include a drive roller  31 , a driven roller  32 , a conveyor belt  33 , and a belt cleaner  34 . The drive roller  31  may be configured to rotate along with an operation in the image forming portion  10 . The driven roller  32  may be spaced away from the drive roller  31  and may be configured to rotate. The conveyor belt  33  may be stretched between the drive roller  31  and the driven roller  32 . The belt cleaner  34  may be configured to remove toner adhering on a surface of the conveyor belt  33 . 
   As the conveyor belt  33  rotates with a recording sheet placed thereon, the recording sheet supplied from the sheet supply tray  21  can be fed to the four image forming units  70 K,  70 Y,  70 M, and  70 C successively. 
   The image forming portion  10  may be a direct-tandem type, where color printing is possible, and may include a scanner unit  60 , the four image forming units  70 K,  70 Y,  70 M, and  70 C, and a fixing unit  80 . 
   The four image forming units  70 K,  70 Y,  70 M, and  70 C may correspond to four color types of toner, such as black, yellow, magenta, and cyan, respectively, and may be arranged in a line along a sheet feeding direction. 
   The scanner unit  60  may be disposed in an upper portion of the housing  3 , and may be configured to form electrostatic latent images on corresponding surfaces of photosensitive drums (image carriers)  71  disposed in the four image forming units  70 K,  70 Y,  70 M, and  70 C, respectively. The scanner unit  60  may include a laser light source, a polygon mirror, fθ lens and reflecting mirrors. 
   A laser beam emitted from the laser light source, based on image data, may be deflected by the polygon mirror, pass through the fθ lenses, and be folded by the reflecting mirror to be directed to a surface of the photosensitive drum  71 , on which an electrical latent image is formed. 
   A drawer unit  70  will be described. 
   The drawer unit  70  may include the four image forming units  70 K,  70 Y,  70 M, and  70 C that form the image forming unit  10 , and may include a slider casing  75  that stores the cartridges  70 K,  70 Y,  70 M, and  70 C therein. The slider casing  75  may be coupled to the housing  3  so as to move in a horizontal direction, i.e., in a front-rear direction of the laser printer  1  in this embodiment, while being supported by rails (not shown) disposed in the frame member of the housing  3 . 
   The four image forming units  70 K,  70 Y,  70 M, and  70 C may be part of a drawer unit  70  that is integrally formed with the slider casing  75 , and the drawer unit  70  may be detachably attached to the housing  3 . As shown in  FIGS. 2-4 , the drawer unit  70  may be attached to and removed from the housing  3  via the opening  3 A in the front-rear direction when the front cover  100  is open. The structure and operation to attach and remove the drawer unit  70  will be described later. 
   The four image forming units  70 K,  70 Y,  70 M, and  70 C may be identical in structure, but with different colors of toner. Thus, in the following description, the structure of the image forming units will be described by using the image forming unit  70 C as an example. 
   As shown in  FIG. 1 , the image forming unit  70 C may include a photosensitive drum  71 , a charger  72 , and an image forming unit  74  inside. A transfer roller  73  may be rotatably supported by the frame member so as to face the photosensitive drum  71  on the opposing side of the conveyor belt  33 . 
   The photosensitive drum  71  may be configured to carry an image that is to be transferred onto a recording sheet. The photosensitive drum  71  may be cylindrically shaped, and its outermost layer may be a positively charged photosensitive layer made of polycarbonate. The charger  72  may be configured to charge the surface of the photosensitive drum  71 . The charger  72  may be disposed away from the photosensitive drum  71 , so as to face the photosensitive drum  71  diagonally rearward from above. 
   The charger  72  according to this illustrative embodiment may be a scorotron charger that charges the surface of the photosensitive drum  71  substantially uniformly and positively by corona discharge from a charging wire made of tungsten or the like. 
   The transfer roller  73  may be disposed to face the photosensitive drum  71 , and may be configured to rotate along with the rotation of the conveyor belt  33 . Also, the transfer roller  73  may apply an electrical charge, having a polarity (a negative charge in this illustrative embodiment) opposite to an electrical charge of the photosensitive drum  71 , to the recording sheet from the bottom side (opposite the print surface) of the recording sheet as it passes through the photosensitive drum  71 . 
   A toner storing portion  74  may include a toner chamber  74 A, a toner supply roller  74 B, a developing roller (developer carrier)  74 C, and an agitator  74 D. Toner may be stored in the toner chamber  74 A. The toner supply roller  74 B and the developer carrier  74 C may be configured to supply toner to the photosensitive drum  71 . The agitator  74 D may be configured to agitate toner stored in the toner chamber  74 A. 
   Toner stored in the toner chamber  74 A may be supplied to the developer carrier  74 C along with the rotation of the toner supply roller  74 B. The toner supplied to the developer carrier  74 C may be carried on a surface of the developer carrier  74 C, regulated to a uniform thickness by a layer thickness regulating blade  74 E, and then supplied to the surface of the photosensitive drum  71  that is exposed to light by the scanner unit  60 . 
   The fixing unit  80  may be disposed rearward from the photosensitive drum  71  with respect to the sheet feeding direction, and may be configured to melt toner transferred onto the recording sheet by heat and fix it to the recording sheet. The fixing unit  80  may be removable from the body frame. 
   The fixing unit  80  may include a heat roller  81  and a pressure roller  82 . The heat roller  81  may be disposed to face the print surface of a recording sheet, and may be configured to give a feeding force to a recording sheet while heating the toner on the recording sheet. The pressure roller  82  may be disposed to face the heat roller  81  from below, and may be configured to press against the heat roller  81 . 
   The heat roller  81  may be rotated in synchronization with the developer carrier  74 C and the conveyor belt  33 . The pressure roller  82  may receive a rotational force from the heat roller  81  via a recording sheet that is sandwiched between the rollers  81 ,  82 . 
   In the image forming portion  10 , an image may be formed on a recording sheet as follows. 
   As the photosensitive drum  71  rotates, the surface of the photosensitive drum  71  may be charged uniformly and positively by the charger  72 , and then exposed to a laser beam emitted from the scanner portion  60  at high speed scanning. In this manner, an electrostatic latent image corresponding to the image to be formed on a recording sheet may be formed on the surface of the photosensitive drum  71 . 
   With the rotation of the developer carrier  74 C, toner carried on the developer carrier  74 C and positively charged makes contact with the photosensitive drum  71 , and is supplied to the electrostatic latent image formed on the surface of the photosensitive drum  71 . The toner may be supplied to the uniformly and positively charged surface of the photosensitive drum  71  at a portion where the potential has become low due to exposure to the laser beam. As a result, the latent image on the photosensitive drum  71  becomes visible and a reversal takes place. Thus, a toner image may be formed on the photosensitive drum  71 . 
   The toner image carried on the photosensitive drum  71  may be transferred onto the recording sheet by a transfer bias applied to the transfer roller  73 . Then, the recording sheet may be fed to the fixing unit  80  and heated by the fixing unit  80  so that the toner transferred onto the recording sheet as the toner image is fixed on the recording sheet, and image formation is finished. 
   Installation and removal of the drawer unit  70  from the laser printer  1  will be described below. 
   When the drawer unit  70  is installed in a normal position, as shown in  FIG. 1 , the photosensitive drum  71  may be disposed in proximity to the conveyor belt  33 . The drawer unit  70  may be fixed in this position, such that the drawer unit  70  cannot be moved in the front-rear direction with respect to the frame member of the housing  3 . The normal position is a position that causes the image forming units  70 C,  70 M,  70 Y,  70 K to form an image on a recording sheet, that is, the position that causes the image forming units  70 C,  70 M,  70 Y,  70 K to print. 
   When the drawer unit  70  is to be removed from the housing  3 , the front cover  100  may be opened, and a handle portion  75 A provided in the slider casing  75  may be grasped to pull the drawer unit  70  toward the opening  3 A. 
   The slider casing  70  of the drawer unit  70  moves on inclined surfaces (not shown) of rails formed on longitudinal ends thereof, the drawer unit  70  entirely moves upward away from the conveyor belt  33  as shown in  FIGS. 2-4 , and rises on the rails extending in the front-rear direction. 
   When the drawer unit  70  is pulled toward the opening  3 A with the drawer unit  70  on the rails extending in the front-rear direction, the drawer unit  70  may be removed from the housing  3 . 
   The front cover  100  may be provided with a first pressing portion  101  and a second pressing portion  102  on a side facing the drawer unit  70 , and may be protrusions or projections extending from the cover  100 . The pressing portions  101 ,  102  may be configured to press the drawer unit  70  to its normal position (toward the inside from the opening  3 A) when the drawer unit  70  is installed in the housing  3 . 
   The first pressing portion  101  may be disposed closer to the hinge mechanism  110  than the second pressing portion  102 . As shown in  FIG. 3 , as the front cover  100  is being closed, the first pressing portion  101  may press against a front end of the slider casing  75  of the drawer unit  70 , forcing the drawer unit  70  toward the normal position. The front end of the slider casing  75  may extend in a width direction of the slider casing  75  of the drawer unit  70 , or a horizontal direction substantially perpendicular to a direction in which the drawer unit  70  is moved. 
   Specifically, the first pressing portion  101  may be disposed in an end of a tip of the feed chute  26 , which is shifted from a guide surface that contacts and guides a recording sheet. As shown in  FIG. 1 , a feed chute  75 B may be disposed on the front of the slider casing  75  to face the guide surface of the feed chute  26  thereby defining the feed path. In other words, the feed chute  75 B may be shifted in the width direction from a position where the drawer unit  70  contacts the first pressing portion  101 . 
   The second pressing portion  102  may be disposed in a position that is close to an upper end of the front cover  100  and away from the hinge mechanism  110  further than the first pressing portion  101 . As shown in  FIG. 4 , the second pressing portion  102  may press the drawer unit  70  toward the normal position by pressing against the handle portion  75 A of the slider casing  75 . The second pressing portion  102  may be formed as a protrusion protruding toward the drawer unit  70 . 
   As illustrated, when the front cover  100  is being closed, the first pressing portion  101  first contacts the drawer unit  70  in advance of the second pressing portion  102  and presses the drawer unit  70  toward the normal position, and then the second pressing portion  102  presses the drawer unit  70  toward the normal position. 
   As shown in  FIG. 5 , the handle portion  75 A may include a first planar surface  75 C that is substantially parallel to the moving direction of the drawer unit  70 , a second planar surface  75 D that faces the front cover  100  and extends in a direction substantially perpendicular to the first planar surface  75 C, and an inclined surface  75 E that is rounded so as to smoothly connect the first planar surface  75 C and the second planar surface  75 D. The tip of the second pressing portion  102  may contact the inclined surface  75 E and press the drawer unit  70 . 
   When the drawer unit  70  is installed in the housing  3 , a user may first press the drawer unit  70  more than half way toward the normal direction as shown in  FIG. 2 , i.e. toward the left in  FIG. 2 . Then, as the user is closing the front cover  100 , the first pressing portion  101  may first contact the feed chute  75 B of the slider casing  75  as shown in  FIG. 3 , and press the drawer unit  7  closer to the normal position. 
   As the user is further closing the front cover  100 , the second pressing portion  102  may contact the handle portion  75 A as shown in  FIG. 4 , and press the drawer unit  70  further closer to the normal position. At this time, a tip of the second pressing portion  102  may make contact with the inclined surface  75 E and press the drawer unit  70 . Thus, as shown in  FIG. 5 , the drawer unit  70  receives a force F 1  directed toward the normal position and a force F 2  directed downward (toward the feed mechanism  30 ). 
   When the drawer unit  70  is moved to inclined surfaces of the rails formed on longitudinal ends thereof, it may be pressed downward with the force F 2  in proximity of the feed mechanism  30  or the conveyor belt  33 , and installed in the normal position. 
   When the drawer unit  70  is installed in the normal position, the tip of the second pressing portion  102  may be located inside the housing  3  offset from the second planar surface  75 D as shown in  FIG. 1  and at a position shifted in a direction perpendicular to the first planar surface  75 C, e.g., upward in this embodiment. 
   An image forming apparatus configured such that a process cartridge is disposed under a top cover of a housing is known. In this type of image forming apparatus, when the process cartridge is inserted into the housing from the top, the process cartridge moves down, under its own weight, to the normal position set in a lower position in the housing. Thus, as the top cover is closed to install the process cartridge into the housing, there is no need to strongly press the process cartridge down at an earlier stage. The image forming apparatus may be configured in any way as long as the process cartridge is pressed only at a final stage when the top cover is nearly closed. 
   However, the laser printer  1  is configured such that the image forming units  70 C,  70 M,  70 Y,  70 K are inserted into and removed from the housing  3  horizontally in the front-rear direction. When the image forming units  70 C,  70 M,  70 Y,  70 K are first inserted into the housing  3 , the image forming units  70 C,  70 M,  70 Y,  70 K are not necessarily subjected to any force to move under their own weight. 
   Thus, to move the image forming units  70 C,  70 M,  70 Y,  70 K mechanically in connection with the closing movement of the front cover  100 , there is a need to press the image forming units  70 C,  70 M,  70 Y,  70 K toward the normal position continuously from the early stage to the final stage of the closing operation of the front cover  100 . 
   In this embodiment, as described above, the first pressing portion  101  presses the drawer unit  70  toward the normal position in an early stage of the closing operation of the front cover  100 , while the second pressing portion  102  presses the drawer unit  70  toward the normal position in a final stage of the closing operation of the front cover  100 . Thus, the drawer unit  70  can be moved toward the normal position continuously from the first stage to the final stage of the closing operation of the front cover  100 . 
   If the drawer unit  70  is pressed with only one of the first and second pressing portions  101 ,  102  continuously from the first stage to the final stage of the closing operation of the front cover  100 , the pressing portion may be worn out early. 
   On the contrary, in this embodiment, the drawer unit  70  may be pressed with both of the first and second pressing portions  101 ,  102  continuously from the first stage to the final stage of the closing operation of the front cover  100 . Thus, the first and second pressing portions  101 ,  102  will suffer less wear. 
   Alternatively, the drawer unit  70  may be pressed only with the second pressing portion  102  continuously from the first stage to the final stage of the closing movement. In this alternative, the second pressing portion  102  may contact the drawer unit  70  upon the first stage of the closing movement, that is, when the front cover  100  is beginning to close. 
   The second pressing portion  102  may be disposed at the end of the front cover  100  away from the hinge mechanism  110 , and the front cover  100  may be pivotally coupled to the housing  3 . When the front cover  100  is fully opened, a distance from the second pressing portion  102  to the drawer unit  70  is greater than a distance from the first pressing portion  101  to the drawer unit  70 . In other words, the second pressing portion  102  may be shorter in length than the first pressing portion  101 . 
   Thus, for configurations in which the drawer unit  70  is pressed only by the second pressing portion  102  during the closing operation of the front cover  100 , the second pressing portion  102  should protrude more, and will increase in size. 
   However, if the second pressing portion  102  increases in size, it obstructs the removal of the drawer unit  70  even when the front cover  100  is fully opened, and it may be difficult to remove the drawer unit  70  easily. 
   When the front cover  100  is completely closed, the second pressing portion  102  may be accommodated in the housing  3 . However, if the second pressing portion  102  increases in size, it may be very hard to spare space for the increased second pressing portion  102  in the housing  3 . 
   As described above, when the cover  100  is fully open, the top end of the first pressing portion  101  is closer to the drawer unit  70  than the top end of the second pressing portion  102 . Thus, the first pressing portion  101  can be brought in contact with the drawer unit  70  from the first stage of the closing operation of the front cover  100  without increasing the size of the first pressing portion  101 . 
   As a result, as long as the arrangement is such that the first pressing portion  101  contacts the drawer unit  70  in advance of the second pressing portion  102  when the front cover  100  is being closed as described above, there is no need to increase the size of the second pressing portion  102 . With this arrangement, the drawer unit  70  can be kept pressed continuously from the first stage to the final stage of the closing operation of the front cover  100 , and space for the second pressing portion  102  can be spared in the housing  3  relatively easily. 
     FIG. 6  shows forces exerted on the front cover  100  and the drawer unit  70 . M indicates a moment that causes the front cover  100  to close. F 0  indicates a force that the front cover  100  presses the drawer unit  70 . F 1  indicates a component of the force F 0  applied in a horizontal direction substantially parallel to the moving direction of the drawer unit  70 . F 2  indicates a component of the force F 0  applied in a vertical direction. As is apparent from  FIG. 6 , the component F 1  may be smaller at an earlier stage of closing movement of the front cover  100 . 
   According to the principle of leverage, the force F 0  may be greater in a position closer to the hinge mechanism  110 . Thus, if the drawer unit  70  is pressed with the first pressing portion  101 , the component F 1  that presses the drawer unit  70  increases. 
   As a result, when the first pressing portion  101  disposed near the hinge mechanism  110  presses the drawer unit  70  during the first stage of the closing operation of the front cover  100 , the drawer unit  70  can be pressed toward the normal position with a greater force, and without a need to increase the force exerted on the front cover  100 . 
   Accordingly, the drawer unit  70  can be pressed toward the normal position while the front cover  100  is closed with a relatively small force such as to prevent wear of the first and second pressing portions  101 ,  102  and to not obstruct removability of the drawer unit  70 . 
   If the arrangement is such that the second pressing portion  102  presses the drawer unit  70  at the second planar surface  75 D, the protrusion forming the second pressing portion  102  contacts the second planar surface  75 D even when the opening  3 A is closed by the front cover  100 . Thus, the laser printer  1  increases in length or a dimension in the front-rear direction at least by a dimension of the protrusion. 
   However, as described above, when the front cover  100  is closed, the tip of the second pressing portion  102  is located inside the housing  3  and above the second planar surface  75 D, as shown in  FIG. 1 , e.g., at a position shifted in a direction perpendicular to the first planar surface  75 C. The protrusion forming the second pressing portion  102  may be located inside further from the second planar surface  75 D. 
   Thus, the size front-to-back of laser printer  1  can be reduced, while the drawer unit  70  can still be pressed toward the normal position. 
   As illustrated, as the drawer unit  70  includes the four image forming units  70 K,  70 Y,  70 M,  70 C, the drawer unit  70  may be heavy compared with a drawer unit for a monochrome laser printer having only one image forming unit. However, in the laser printer  1 , the drawer unit  70  can be moved toward the normal position while the front cover  100  is closed with a relatively small force. This arrangement is effective especially when applied to the color laser printer  1  in which the drawer unit  70  becomes relatively heavy. 
   A second embodiment will be described with reference to  FIG. 7 . 
   In the second embodiment, a recessed portion  103  may be formed on the front cover  100  and a protrusion  3 B may be formed on the housing  3 . When the front cover  100  is closed to the housing  3 , the recessed portion  103  may be engaged with the protrusion  3 B. Alternatively, the recessed portion  103  may be formed on the housing  3  and the protruding portion  3 B may be formed on the front cover  100 . 
   With this structure, for example, even if a great impact (acceleration) acts on the laser printer  1  during transportation and a great force (inertia force) acts on the front cover  100 , the force (inertia force) exerted on the front cover  100  can be received by the hinge mechanism  110  and the protrusion  3 B of the housing  3 . 
   Thus, the hinge mechanism  110 , especially pins thereof, can be prevented from undergoing a great force, thereby minimizing trouble that is likely to occur during transportation of the laser printer  1 , such as damage on the hinge mechanism  110 . 
   The discussion above addresses a color laser printer. However, the features herein may be applied to other printers, such as a monochrome laser printer. 
   The discussion above addresses a direct tandem-type laser printer. However, the present application is not limited to this type of printer. 
   As illustrated, the second pressing portion  102  contacts the handle portion  75 A of the slider casing  75 . However, the contact may be made elsewhere. 
   As illustrated, the first pressing portion  101  is formed on the feed chute  26  disposed on the front cover  100 . However, the portion may be formed elsewhere. 
   As illustrated, the hinge mechanism  110  includes long holes and pins. However, other hinge mechanisms may be used. 
   The inclined surface  75 E is shown as rounded in the figures. However, the inclined surface  75 E may be flat or beveled. Additionally, the first and second planar surfaces are illustrated in  FIG. 5  as being substantially perpendicular to one another. These surfaces need not be exactly perpendicular, however, and other angles may be used. For example, the surfaces may form an oblique angle, such as 60°, as illustrated in the example handle  75 A in  FIG. 1 . 
   While the features herein have been described in connection with various example structures and illustrative aspects, it will be understood by those skilled in the art that other variations and modifications of the structures and aspects described above may be made without departing from the scope of the invention. Other structures and aspects will be apparent to those skilled in the art from a consideration of the specification or practice of the features disclosed herein. It is intended that the specification and the described examples only are illustrative with the true scope of the inventions being defined by the following claims.