Abstract:
An image forming device includes a frame, a subunit detachably attached to the frame, a frame-side positioning portion, a subunit-side positioning portion, the subunit being positioned relative to the frame by making the subunit-side positioning portion contact the frame-side positioning portion, a contact regulating member attached to the frame movably between a location to contact the subunit before the subunit-side positioning portion comes into contact with the frame-side positioning portion in process of the subunit being attached to the frame from a detached state and a location to be kept from contacting the subunit, a pressing member attached to the frame movably between a position to press the subunit such that the subunit-side positioning portion is made contact the frame-side positioning portion and a position to be kept from pressing the subunit, and an interlocking member interlocking movements of the contact regulating member and the pressing member.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority under 35 U.S.C. §119 from Japanese Patent Application No. 2008-235025 filed on Sep. 12, 2008. The entire subject matter of the application is incorporated herein by reference. 
       BACKGROUND  
       [0002]    1. Technical Field 
         [0003]    The following description relates to one or more image forming devices provided with an image forming unit configured to form an image on a recording sheet, more particularly to one or more image forming devices provided with the image forming unit at least part of which is configured as a separate subunit detachably supported by one or more frames. 
         [0004]    2. Related Art 
         [0005]    So far an image forming device has been proposed that includes an image forming unit, supported by one or more frames, at least part of which unit is configured as a separate subunit supported by the frames so as to be inserted into and pulled from the frame. For example, in a tandem-type laser printer that has four sets of a photoconductive drum and a development cartridge serially aligned, such a configuration has been proposed that the four sets of the photoconductive drum and the development cartridge are provided as an integrated subunit configured to be inserted into and pulled from one or more frames. In this case, the four sets of the photoconductive drum and the development cartridge can integrally be pulled from the frames, and thus such a configuration leads to easier maintenance of the image forming device. 
         [0006]    Further, in the image forming device of this kind, a technique has been proposed in which the position of the subunit in the frames is determined by bringing a subunit-side positioning portion provided to the subunit into contact with a frame-side positioning portion provided to the frames. For instance, a technique has been proposed in which the position of the subunit in the frame is determined by engaging a notched portion as the subunit-side positioning portion that is formed at a leading end of the subunit in an inserting direction with a reference shaft as the frame-side positioning portion that links between right and left frames. 
         [0007]    Moreover, in the image forming device of this kind, a configuration has been proposed to certainly determine the position of the subunit, which configuration has a pressing member configured to press the subunit in such a direction as to bring the subunit-side positioning portion into contact with the frame-side positioning portion. Furthermore, in the image forming device of this kind, a configuration has been proposed to prevent the subunit-side positioning portion from colliding against the frame-side positioning portion when the subunit is set in, which configuration has a contact regulating member configured to regulate the contact of the subunit-side positioning portion with the frame-side positioning portion. 
       SUMMARY  
       [0008]    However, when the pressing member and the contact regulating member are separately provided, it results in a higher manufacturing cost and more difficult operations for the pressing member and the contact regulating member when the subunit is attached or detached. 
         [0009]    Aspects of the present invention are advantageous to provide one or more improved image forming devices each of which includes a contact regulating member configured to regulate contact of a subunit-side positioning portion with a frame-side positioning portion and a pressing member configured to press an subunit in such a direction as to bring the subunit-side positioning portion into contact with the frame-side positioning portion, and each of which makes it possible to present a lower manufacturing cost and a more improved operationality of the image forming device. 
         [0010]    According to aspects of the present invention, an image forming device is provided, which includes a frame, a subunit detachably attached to the frame, a frame-side positioning portion provided to the frame, a subunit-side positioning portion provided to the subunit, the subunit-side positioning portion being configured to position the subunit relative to the frame by establishing contact with the frame-side positioning portion, a contact regulating member attached to the frame movably between a first location where the contact regulating member establishes contact with the subunit before the subunit-side positioning portion comes into contact with the frame-side positioning portion in process of the subunit being attached to the frame from a detached state and a second location where the contact regulating member is kept from contacting the subunit, a pressing member attached to the frame movably between a first position where the pressing member presses the subunit in such a first direction as to bring the subunit-side positioning portion into contact with the frame-side positioning portion and a second position where the pressing member is kept from pressing the subunit, and an interlocking member configured to interlock movement of the contact regulating member to the first location with movement of the pressing member to the first position and to interlock movement of the contact regulating member to the second location with movement of the pressing member to the second position. 
     
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
         [0011]      FIG. 1  schematically shows an internal configuration of an image forming device in an embodiment according to one or more aspects of the present invention. 
           [0012]      FIGS. 2A and 2B  are respectively a front view and a side view of a drum subunit immediately after being inserted between metal plate frames in the embodiment according to one or more aspects of the present invention. 
           [0013]      FIGS. 2C and 2D  are respectively a front view and a side view of the drum subunit completely set between metal plate frames in the embodiment according to one or more aspects of the present invention. 
           [0014]      FIGS. 3A and 3B  are perspective views illustrating a detailed configuration and an operation of a leg portion of the drum subunit and an operation part of the metal plate frame in the embodiment according to one or more aspects of the present invention. 
           [0015]      FIG. 4A  is a top view showing engagement between bevel gears fixed to respective shafts immediately after the drum subunit is inserted between the metal plate frames in the embodiment according to one or more aspects of the present invention. 
           [0016]      FIG. 4B  is a top view showing engagement between the bevel gears fixed to the respective shafts when the drum subunit is completely set between the metal plate frames in the embodiment according to one or more aspects of the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0017]    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. 
       Overall Configuration of Laser Printer  
       [0018]    Hereinafter, an embodiment according to aspects of the present invention will be described with reference to the accompanying drawings.  FIG. 1  schematically shows an internal configuration of an image forming device  100  in an embodiment. It is noted that the following description will be given with the left side in  FIG. 1  defined as the front side of the image forming device  100 . Further,  FIG. 1  schematically shows a configuration of each element with the configuration partially omitted for the sake of explanatory convenience, and the figure is not necessarily consistent with other drawings. 
         [0019]    As illustrated in  FIG. 1 , the image forming device  100  of the embodiment includes a belt unit  10  configured with a feeding belt (transfer belt)  13  wound around a driving roller  11  and a driven roller  12 , and four process units  20 , corresponding to four colors of black (K), yellow (Y), magenta (M), and cyan (C), respectively, which are disposed above the belt unit  10 . The four process units  20  are aligned in a front-to-rear direction in the order of the black (K), yellow (Y), magenta (M), and cyan (C) from the front side, and thus configured as a direct tandem color image forming unit. In addition, the four process units  20  are respectively held by four containers (not shown) provided to a drum subunit  50  (see  FIG. 2 ), in an individually attachable and detachable manner. 
         [0020]    Each of the process units  20  is configured with a photoconductive drum  21 , a scorotron charger  22 , and a development cartridge  24 . The photoconductive drum  21  includes a metal drum body connected to ground with a surface thereof covered with a positively-electrifiable photoconductive layer. 
         [0021]    The scorotron charger  22  is disposed a predetermined distance away from the photoconductive drum  21 , at an obliquely upper rear side of the photoconductive drum  21 , so as to face the photoconductive drum  21 . The scorotron charger  22  is configured to cause an electrification wire thereof such as a tungsten wire to generate corona discharge and to charge the surface of the photoconductive drum  21  positively and evenly. The development cartridge  24  has a toner container  25  provided therein. The development cartridge  24  is a known one configured to positively charge, in a frictional manner, one-component positively-electrifiable nonmagnetic toner of a corresponding one color of the black (K), cyan (C), magenta (M), and yellow (Y), which is stored in the toner container  25  and to supply the toner to the photoconductive drum  21  via a development roller  26 . 
         [0022]    Further, the belt unit  10  has four transfer rollers  14  provided to face the photoconductive drums  21  across the feeding belt  13 , respectively. The feeding belt  13  is driven to turn in the clockwise direction in  FIG. 1  by clockwise rotation of the driving roller  11 . A sheet P is fed onto the surface of the feeding belt  13  by various rollers (not shown) such as a feed roller, from a feed tray (no shown) inserted into a lower portion of the image forming device  100 . Then, the sheet P is conveyed to the rear side of the image forming device  100 , passing through a position to face each photoconductive drum  21 . 
         [0023]    A scanner unit  30  is provided above the process units  20 . The scanner unit  30 , which is a known one configured to scan and expose the photoconductive drums  21 , includes semiconductor lasers (not shown) configured to emit laser beams Lk, Ly, Lm, and Lc corresponding to four colors of image data, respectively, and polygon mirrors (not shown) configured to deflect the laser beams L (Lk, Ly, Lm, and Lc), respectively. 
         [0024]    Therefore, first, the surface of each photoconductive drum  21  is charged evenly and positively by the charger  22  while being rotating. Thereafter, the surface of the photoconductive drum  21  is exposed through high-speed scanning of the laser beam L emitted by the scanner unit  30 , and thus an electrostatic latent image, which corresponds to an image to be formed on the sheet P, is formed on the surface of the photoconductive drum  21 . Subsequently, the positively charged toner held on the development roller  26  is supplied to the electrostatic latent image formed on the surface of the photoconductive drum  21  through rotation of the development roller  26  when facing and contacting the photoconductive drum  21 . Thereby, the electrostatic latent image on the photoconductive drum  21  is developed into a visible image as a toner image formed with the toner attached to exposed portions on the surface of the photoconductive drum  21 . 
         [0025]    After that, the toner image held on the surface of each photoconductive drum  21  is sequentially transferred onto the sheet P by a negative transfer bias applied to the transfer roller  14  under constant current control when the sheet P being conveyed by the feeding belt  13  passes between the photoconductive drum  21  and the transfer roller  14 . Next, the sheet P with the toner transferred thereon in this manner is conveyed to a fixing unit  40  provided behind the belt unit  10 . 
         [0026]    The fixing unit  40  includes a heating roller  41  that is provided with a heat source and configured to be rotated, and a pressing roller  42  that is disposed below the heating roller  41  so as to face and press the heating roller  41  and configured to be rotated in accordance with rotation of the heating roller  41 . The fixing unit  40  heats the sheet P with four colors of toner images formed thereon while pinching and conveying between the heating roller  41  and the pressing roller  42 , and thus thermally fixes the toner images on the sheet P. Then, the sheet P with the toner images thermally fixed thereon is ejected by various rollers (not shown) onto a catch tray (not shown) provided on an upper surface of the image forming device  100 . 
       Configuration of Main Body Frame  
       [0027]    As illustrated in  FIGS. 2A to 2D , the drum subunit  50  in which the four process units  20  are stored is configured as a ship-shaped container with an upper side thereof opened. The drum subunit  50  is supported by a pair of metal plate frames  70  provided at right and left sides in the image forming device  100  so as to be inserted and pulled relative to the frames  70  in the front-to-rear direction. The drum subunit  50  has a handle  51  provided at the center of a front end. Gripping the handle  51 , at the front side of the image forming device  100 , a user can insert into or pull from between the metal plate frames  70 . Further, the following configuration is not shown in any drawings, but the aforementioned scanner unit  30  is disposed above the metal plate frames  70 , and an outer surface of each metal plate frame  70  is covered with a resin exterior cover. When a front cover provided to the exterior cover in an openable and closable manner is opened, the drum subunit  50  can be inserted and pulled relative to the metal plate frames  70  at the front side of the image forming device  100 . 
         [0028]      FIG. 2A  is a front view of the drum subunit  50  immediately after being inserted between the metal plate frames  70 .  FIG. 2B  is a side view showing a configuration of the drum subunit  50  in the same state as above and surrounding members. As illustrated in  FIGS. 2A and 2B , rollers  52  are disposed at an upper rear end so as to protrude from a right side face and a left side face, respectively. Each of the metal plate frames  70  is provided with a guide  72  configured to guide a corresponding one of the rollers  52  in the front-to-rear direction. Each of the metal plate frames  70  is configured as a plate that vertically stands and faces the other. The guides  72  are respectively provided on inner surfaces of the metal plate frames  70  and configured to protrude inward. An upper surface of each guide  72  that supports the roller  52  is configured with most thereof provided horizontally in the front-to-rear direction and a rear end thereof inclined down (inclined portion  72 A). Therefore, when the drum subunit  50  is pushed rearward to a certain degree and the rollers  52  are put onto the inclined portions, the drum subunit  50  is guided further rearward owing to its own weight. 
         [0029]    Further, the drum subunit  50  has supporting shafts  53  provided at the front end thereof, which are configured to protrude from the right and left side faces of the drum subunit  50 , respectively. Each of the metal plate frames  70  has a supporting shaft insertion hole  73  formed at a front end thereof, which is open forward such that the supporting shaft  53  is inserted thereinto from the front side. A lower end of each supporting shaft insertion hole  73  that supports the supporting shaft  53  is halfway inclined down rearward. Thus, when the drum subunit  50  is pushed rearward to a certain degree, the drum subunit  50  is guided further rearward owing to its own weight. 
         [0030]    Further, as illustrated in  FIG. 2B , a reference shaft  74  formed in a shape of round bar is provided behind the metal plate frames  70  so as to extend horizontally in the right-to-left direction. At a lower rear end of the drum subunit  50 , a notched portion  54  is formed to engage with the reference shaft  74 .  FIGS. 2C and 2D  are respectively a front view and a side view of the drum subunit  50  completely set between the metal plate frames  70 . As illustrated in  FIG. 2D , the notched portion  54  is formed at a rear end of the drum subunit  50  to be open in a laterally-facing U-shape. Due to contact between the notched portion  54  and the reference shaft  74 , the rear end of the drum subunit  50  is positioned relative to the metal plate frames  70  in the vertical direction and the front-to-rear direction. It is noted that, in  FIGS. 2A and 2C , some of elements provided at the rear side such as the aforementioned reference shaft  74  and below-mentioned stoppers  86  are not shown for the sake of explanatory convenience. 
         [0031]    Between the drum subunit  50  and a lower portion of the metal plate frame  70  at each of the right and left sides, a shaft  81  is provided to extend in the front-to-rear direction. Each shaft  81  is supported by a corresponding one of the metal plate frames  70  rotatably around an axial direction thereof. A substantially rectangular parallelepiped operation part  82  is fixed to a front end of each shaft  81 , and configured to swing around the shaft  81  integrally with the shaft  81 . More specifically, each of the operation parts  82  is configured to swing between a first position where the operation part  82  is placed to extend up from the shaft  81  and a second position where the operation part  82  is placed to extend inward in the right-to-left direction. As illustrated in  FIG. 2A , in a state where each of the operation parts  82  is set in the first position, the operation parts  82  do not disturb any operation of inserting and pulling the drum subunit  50 . Thus, in this state, the drum subunit  50  can be inserted into and pulled from between the metal plate frames  70 . 
         [0032]    Meanwhile, when each of the operation parts  82  is swung and set to the second position with the drum subunit  50  inserted between the metal plate frames  70 , the drum subunit  50  is pressed rearward so as to certainly bring the notched portion  54  into contact with the reference shaft  74 . More specifically, as illustrated in  FIGS. 2A to 2D , two leg portions  55  are formed at lower front ends of the drum subunit  50 , so as to extend down from a lower right end and a lower left end of the drum subunit  50 , respectively. As illustrated in  FIG. 3 , a chamfer  55 A is formed at an outer front edge of each leg portion  55  in the right-to-left direction. Further, a chamfer  82 A is formed at an edge which corresponds to an inner rear edge of each of the operation parts  82  set in the first position. Therefore, after the drum subunit  50  is inserted into between the metal plate frames  70 , when each operation part  82  set in the first position as shown in  FIG. 3A  is swung in a direction indicated by an arrow A up to the second position as shown in  FIG. 3B , a pressing force as indicated by an arrow B is applied to each leg portion  55 . The pressing force presses the drum subunit  50  rearward to certainly bring the notched portion  54  into contact with the reference shaft  74 . 
         [0033]    Referring back to  FIG. 2 , at a lower rear end of the drum subunit  50 , an engagement portion  56  is formed to be notched in an L-shape. Additionally, between the metal plate frames  70 , two stoppers  86 , configured to engage with the engagement portion  56 , are provided swingably around a shaft  87 . The shaft  87  is provided between the metal plate frames  70  to extend in the right-to-left direction and configured to rotate around an axis line thereof. The two stoppers  86  are provided to correspond to a right side portion and a left side portion of the drum subunit  50  at which the aforementioned engagement portion  56  is formed, respectively. Each of the stoppers  86  is configured substantially as a rectangular parallelepiped to swing integrally with the shaft  87 . More specifically, each of the stoppers  86  is configured to swing between a first state where the stopper  86  vertically extends up from the shaft  87  as shown in  FIG. 2B  and a second state where the stopper  86  horizontally extends rearward from the shaft  87  as shown in  FIG. 2D . As illustrated in  FIGS. 4A and 4B , two bevel gears  89  are fixed to both ends of the shaft  87  in the right-to-left direction, respectively. Additionally, two bevel gears  88  are fixed to rear ends of the shafts  81 , respectively. Thereby, the bevel gears  88  are respectively engaged with the bevel gears  89  at the both ends of the shaft  87  in the right-to-left direction, so as to transmit a rotational motion between the shafts  81  and the shaft  87 . 
         [0034]    Here, the engagement between the bevel gears  88  and  89  is adapted to set the stoppers  86  to the first state when the operation parts  82  are set to the first position and to the second state when the operation parts  82  are set to the second position. When the stoppers  86  are set to the first state, the stoppers  86  are engaged with the engagement portion  56  before the notched portion  56  completely comes into contact with the reference shaft  74 . Meanwhile, when the stoppers  86  are set to the second state, the stoppers  86  allow the notched portion  56  to contact the reference shaft  74  without causing interference with the drum subunit  50  including the engagement portion  56 . 
       Effects of Embodiment  
       [0035]    According to the image forming device in the embodiment, when the two operation parts  82  are set to the first position, the drum subunit  50  can be inserted into or pulled from between the two metal plate frames  70 , passing between the two operation parts  82 . Moreover, at this time, the stoppers  86  are set in the first state, and thus it is possible to prevent the notched portion  54  from colliding against the reference shaft  74  when the drum subunit  50  is inserted. 
         [0036]    Meanwhile, after the drum subunit  50  is inserted, by swinging the two operation parts  82  to the second position, the stoppers  86  are swung to the second state in conjunction with the movement of the operation parts  82 . Thereby, it is possible to bring the notched portion  54  completely into contact with the reference shaft  74 . Additionally, at this time, the leg portions  55  are pressed by the pressing force from the operation parts  82 . Thus, it is possible to certainly bring the notched portion  54  into contact with the reference shaft  74 . 
         [0037]    Further, contrary to the operation when the drum subunit  50  is inserted, when the drum subunit  50  is pulled out, the two operation parts  82  are swung to the first position. In conjunction with the swing motions of the operation parts  82 , the stoppers  86  are swung to the first state. Owing to the swing motions of the stoppers  86 , the drum subunit  50  is pushed forward so as to help the user pull the drum subunit  50  more easily. 
         [0038]    Thus, in the embodiment, the swing motions of the operation parts  82  are interlocked with the swing motions of the stoppers  86  through the bevel gears  88  and  89 . Therefore, it is possible to improve the operationality of the image forming device  100 . Further, since it is not necessary to provide an operation part individually for achieving each swing motion, it is possible to reduce the manufacturing cost of the image forming device  100 . Moreover, since the drum subunit  50  is pushed in conjunction with the operations of the operation parts  82  for pulling the drum subunit  50 , the operationality of the image forming device  100  is further improved. 
         [0039]    Hereinabove, the embodiment according to aspects of the present invention has been described. The present invention can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention can be practiced without reapportioning to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention. 
         [0040]    Only an exemplary embodiment of the present invention and but a few examples of its versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. For example, the following modifications are possible. 
       Modifications  
       [0041]    In the aforementioned embodiment, the two stoppers  86  are provided to correspond to the right side portion and the left side portion of the drum subunit  50  at which the engagement portion  56  is formed, respectively. However, only a single stopper may be provided at a center in the right-to-left direction. 
         [0042]    In the aforementioned embodiment, the operation parts  82  are configured to be operable directly by the user. However, a user-operable member configured to be interlocked with the operation parts  82  may separately be provided. In this case, the user-operable member may be configured to be interlocked with a pressing member for pressing another position (for example, a center in the front-to-rear direction) of the drum subunit  50  rearward. However, in this respect, since the operation parts  82  are configured to be directly operable by the user in the aforementioned embodiment, it leads to more simplified configuration and more reduced manufacturing cost of the image forming device  100  than the configuration with the user-operable member separately provided. 
         [0043]    Further, a configuration other than the bevel gears  88  and  89  may be applied to interlock the operation parts  82  and the stoppers  86 . For instance, the shafts  81  and  87  may be connected via a spring. Alternatively, a worm provided to each shaft  81  may be engaged with a worm wheel provided to the shaft  87 . In this case, since a driving force is not transmitted from the stoppers  86  to the operation parts  82 , it is possible to more efficiently prevent the operation parts  82  from swinging when the stoppers  86  are pressed by the drum subunit  50 . However, in this respect, the aforementioned embodiment in which a driving force can be transmitted from the stoppers  86  to the operation parts  82  may present more improved operationality to achieve complete insertion of the drum subunit  50  without touching the operation parts  82 . It is noted that, of course, a certain degree of resistance is desired to be caused when a driving force is transmitted from the stoppers  86  to the operation parts  82  in order to prevent the notched portion  54  from colliding against the reference shaft  74 . Furthermore, the operation parts  82  and the stoppers  86  may move through sliding motions instead of the swing motions.