Patent Publication Number: US-2011062835-A1

Title: Image forming apparatus including supporting legs

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. Ser. No. 11/691,693, filed Mar. 27, 2007, and claims the benefit of priority to Japanese Patent Application No. 2006-086620 filed Mar. 27, 2006 and Japanese Patent Application No. 2006-258055 filed Sep. 22, 2006, the entire contents of which are each incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an apparatus having a plurality of movable supporting legs to stabilize the apparatus. 
     BACKGROUND OF THE INVENTION 
     In an apparatus as an image forming apparatus, a measurement device, an electronic device, and an electric appliance, various type of supporting legs attached to the bottom of the apparatus is disclosed in the related art as following: Japanese Examined Patent Application No. 1992-40198, Japanese Patent Laid-Open Application No. 2001-22142, Japanese Patent Laid-Open Application No. 2001-51462, and Japanese Patent Laid-Open Application No. 2002-287452. 
     Specifically, the Japanese Patent Laid-Open Application No. 2001-51462 discloses an image forming apparatus that includes: a first abdominal plate having a bottom portion to which the first supporting leg or second supporting leg is provided, a second abdominal plate having a bottom portion that the first supporting leg or second supporting leg is provided, and connection plates that connect the first abdominal plate and the second abdominal plate. 
     More specifically, the Japanese Patent Laid-Open Application No. 2001-51462 discloses an image forming apparatus in which the supporting legs make a substantial triangle including the vertical projection of the center of gravity of the device on the installation surface. 
     The supporting leg should be disposed to keep the apparatus stably on the installation surface by considering the center of gravity of the apparatus. For example, in the apparatus having three supporting legs attached to the bottom of the apparatus which make a triangle on the installation surface, it is preferable that the triangle is made to include the vertical projection of the center of gravity of the apparatus. 
     The center of gravity of some apparatuses change by altering the configuration of the apparatus, as described below. 
     The image forming apparatus is configured by a main unit and an adjunct unit. The main unit may be a basic unit and the adjunct unit may be an optional unit. Generally, the center of gravity is widely moved when the optional unit is added to the basic unit. If the position of the supporting legs provided to the image forming apparatus is defined by considering only the center of gravity of the image forming apparatus having the basic unit, the image forming apparatus having the basic unit and the optional unit mounted on the basic unit may not be set stably on the installation surface. In contrast, if the position of the supporting legs are defined by considering only the center of gravity of the image forming apparatus having basic unit and the optional unit, the image forming apparatus having only the basic unit may not be set stably on the installation surface. 
     SUMMARY OF THE INVENTION 
     An apparatus or an image forming apparatus including a main body having a first supporting leg fixed to the main body, a second supporting leg configured to be connectable to the main body, and the position of the main body to connect the second supporting leg is selectable. The apparatus may be stable on the installation surface if the center of gravity of the apparatus is transformed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present invention, and many of the attendant advantages thereof, will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view showing an overall configuration of an image forming apparatus having only a basic unit according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of an image forming apparatus having basic unit and an optional unit mounted on the basic unit according to an embodiment of the present invention; 
         FIG. 3  is an enlarged cross-section view of an image forming apparatus according to an embodiment of the present invention; 
         FIG. 4A  is a horizontal view showing a configuration of supporting legs at a bottom plate of an image forming apparatus according to an embodiment of the present invention; 
         FIG. 4B  is a horizontal view showing a configuration of supporting legs at a bottom plate of an image forming apparatus according to an embodiment of the present invention. 
         FIG. 5A  is a perspective view showing a holding portion at a bottom plate of an image forming apparatus and a supporting leg configured to be connectable to the holding portion; 
         FIG. 5B  is a cross-section view showing a holding portion at a bottom plate of an image forming apparatus and a supporting leg configured to be connectable to the holding portion; 
         FIG. 5C  is a cross-section view showing a holding portion at a bottom plate of an image forming apparatus and a supporting leg configured to be connectable to the holding portion; 
         FIG. 5D  is a cross-section view showing a holding portion at a bottom plate of an image forming apparatus and a supporting leg configured to be connectable to the holding portion; 
         FIG. 6  is a perspective view showing an overall configuration of an image forming apparatus having a first abdominal plate having a bottom portion that provides a supporting leg and a second abdominal plate having a bottom portion that provides a supporting leg according to an embodiment of the present invention; 
         FIG. 7  is a perspective view showing an overall configuration of an image forming apparatus having a first abdominal plate having a bottom portion that provides a supporting leg and a second abdominal plate having a bottom portion that provides a supporting leg according to an embodiment of the present invention; 
         FIG. 8  is a horizontal view showing a configuration of a first abdominal plate having a bottom portion that provides a supporting leg and a second abdominal plate having a bottom portion that provides a supporting leg according to an embodiment of the present invention; and 
         FIG. 9  is a horizontal view showing a configuration of a first abdominal plate having a bottom portion that provides a supporting leg and a second abdominal plate having a bottom portion that provides a supporting leg according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention are described in detail referring to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. 
       FIG. 1  is a perspective view showing an overall configuration of the image forming apparatus having a basic unit indicated “BU” according to an embodiment of the present invention.  FIG. 3  is a cross sectional view of the image forming apparatus having the basic unit depicted in  FIG. 1   
       FIG. 2  is a perspective view of an image forming apparatus having a basic unit and an optional unit as indicated “OU” mounted on the basic unit according to an embodiment of the present invention. 
     As illustrated in  FIG. 1  and  FIG. 3 , the main body  1  of the image forming apparatus includes a first chassis  2 , a bottom plate  3  and various image forming devices provided in the first chassis  2 . Supporting legs  20 ,  21 ,  22  are attached to the bottom plate  3  of the image forming apparatus. 
     As illustrated in  FIG. 3 , the first chassis  2  contains photo conductor drums  4 Y,  4 C,  4 M,  4 BK as image bearing members, and an intermediate transfer belt  5 , which is held by a plurality of holding rollers. 
     Next, the process of forming an image will be described. 
     The photo conductor drums  4 Y,  4 C,  4 M,  4 BK are driven counterclockwise, and the intermediate transfer belt  5  is driven in the direction indicated by arrow A. The photo conductor drum  4 Y is charged to predetermined polarity by a charging roller  6 . Writing unit  7  irradiates laser beam L according to modulated signal to the charged surface of the photoconductor drum  4 Y, and a latent image is formed on the photoconductor drum  4 Y. A developer  8  develops the latent image with yellow toner and a toner image is formed as a visible image on the photoconductor drum  4 Y. The toner image is electrically transferred to the intermediate transfer belt  5  by a first transfer roller  9 . A first cleaning unit  10  removes residual toner from the photoconductor drum  4 Y after the toner image is transferred to the intermediate transfer belt  5 . In processes similar to that described above, a cyan toner image, a magenta toner image, and a black toner image are formed on each photoconductor drum  4 C,  4 M, and  4 BK, and transferred to the intermediate transfer belt  5 . 
     Below the intermediate transfer belt  5  is a sheet feeding device. The sheet feeding device includes a sheet feeding cassette  11  that accommodates recording medium P, which may include recording paper or a resin sheet, and a sheet feeding roller  12 . The topmost recording medium P of the stack is fed by the sheet-feeding roller  12 . The recording medium P is fed to the second transfer portion between the intermediate transfer belt  5  and a second transfer roller  13  that faces the intermediate transfer belt. 
     At the second transfer portion, the toner image on the intermediate transfer belt  5  is electrically transferred to the recording medium P by the second transfer roller  13 , thus, forming a color toner image on the recording medium P. 
     The recording medium P then goes through a fixing device  14 , which fixes the image to the recording medium P using heat and pressure. After passing through the fixing device  14 , the recording medium P is discharged onto a discharging portion  15  formed at a topmost surface of the main body  2 . 
     A second cleaning unit  16  for the intermediate transfer belt  5  removes a residual toner on the intermediate transfer belt  5  after transformation of the toner image to the recording medium P. 
     As illustrated  FIG. 2 , the main body  100  includes BU as the basic unit and OU as the optional unit mounted on the BU. In this embodiment the OU is an image scanner, which includes a second chassis  25 , a contact glass  23  provided to top portion of the second chassis  25 , and a pressing board  24  rotatably attached to the second chassis  25 . The image scanner is configured to hold an original (not shown) on the contact glass  23  using the pressing board  24 , and read the image of the original. The read image is then printed to the recording medium P as described above. The image forming apparatus illustrated  FIG. 2  may function as both, or either, a copy machine and a printer, for example. 
     A user who requests the image forming apparatus having only the printer function can have the image forming apparatus illustrated in  FIG. 1  and  FIG. 3  (e.g., without the image scanner attachment). A user who requests the image forming apparatus having both printer and copy functions can have the image forming apparatus illustrated in  FIG. 2  (e.g., with the document scanner attached). As described above, each image forming apparatus has BU as basic unit and OU as optional unit can mounted to the BU. 
     In the image forming apparatus as illustrated in  FIG. 1  and  FIG. 2 , a first chassis  2  includes a bottom plate  3  and various image forming devices provided in the first chassis  2 . The supporting legs  20 ,  21 ,  22  are provided on the bottom of the first main body  1  or second main body  100 . The supporting legs  20 ,  21 ,  22  hold the first main body  1  or the second main body  100  on an installation surface S. In this embodiment the supporting legs  20 ,  21 ,  22  are provided on the bottom plate  3  of the first main body  1  or the second main body  100 . Lines that connect the supporting legs  20 ,  21 ,  22  make triangles TR 1 , TR 2 . 
     As illustrated in  FIG. 1  and  FIG. 2 , the center of gravity of the first main body  1  is defined as “G 1 ,” and the center of gravity of the second main body  100  is defined as “G 2 .” The vertical projection of G 1 , G 2  to the installation surface is defined as “g 1 ,” and “g 2 ,” respectively. The supporting legs  20 ,  21 ,  22  are configured such that g 1  is within the perimeter of TR 1 , and g 2  is within the perimeter of TR 2 . By such a configuration, the first main body  1  and the second main body  100  are stable. 
     If the first main body  1  or second main body  100  become distorted; the quality of the color image on the recording medium may decrease. Even if the image forming apparatus is a black and white printer or copying machine, the quality of the image may be decrease. The image quality may be improved by setting the first main body  1  or second main body  100  at three point. 
     It is preferable that the triangles TR 1  or TR 2  made by the lines that connect the supporting legs  20 ,  21 ,  22  include the vertical projections g 1  or g 2  of the center of gravity of the apparatus as projected on the installation surface. Specifically, it is preferable that the center of gravity of the triangle is approximated to the vertical projection as g 1  or g 2  of the center of gravity of the first main body  1  or second main body  100  to the installation surface. 
     In  FIG. 2 , the optional image scanner unit OP has remarkable weight. Also, the image scanner is provided biased far from the center of gravity G 1  of the basic unit BU to allow for easy access of the recording medium P discharged on the discharging portion  15 . For the reason described above, the center of gravity G 1  of the main body  1  is positioned far from the center of gravity G 2  of the main body  100 . The center of gravity of the main body is transformed based on whether the main body includes the option unit or only the basic unit. Generally, a ratio of the option unit to basic unit may be from 1/4 to 1/3. 
     As described above, since the center of gravity of the main body  1  or the main body  100  may be transformed based on whether the main body  1  or the main body  100  includes the option unit, the first main body  1  or the second main body  100  may not be set stable on the installation surface if the supporting legs  20 ,  21 ,  22  are permanently fixed to the same place of the bottom of the first main body  1  or the second main body  100 . 
     Accordingly, in this embodiment, the position at which at least one of the supporting legs is connected to the bottom of the first main body  1  or the second main body  100  is selectable. 
       FIG. 4A  is a horizontal view showing a configuration of the supporting legs  20 ,  21 ,  22  provided on a bottom plate  3  of the main body  1  that does not include option unit OU as illustrated in  FIG. 1  and  FIG. 3 . 
       FIG. 4B  is a horizontal view showing a configuration of the supporting legs  20 ,  21 ,  22  provided to a bottom plate  3  of the main body  100  including the option unit OU as illustrated in  FIG. 2 . As illustrated in  FIG. 4A  and  FIG. 4B , the supporting legs  20 ,  21 ,  22  are indicated with hatching. 
     In this embodiment supporting leg  20  is configured such that the part of the bottom of the first main body  1  or the second main body  100  connected to the supporting leg  20  is selectable.  FIG. 4A  and  FIG. 5B  show an example of a holding portion that attaches the supporting leg  20  to the bottom plate  3 . As illustrated in  FIG. 5A , a holding portion  28  is configured as a square trench that is provided at inside of a square-protruding portion  27  on the bottom plate  3 . The supporting leg  20  is placed in the holding portion  28 , and adhered by an adhesive to the bottom plate  3 . 
     As illustrated in  FIG. 4A  and  FIG. 4B , a plurality of the holding portions  28  are provided to the bottom plate  3 . The holding portions  28  include a first holding portion  28 A and a second holding portion  28 B. In  FIG. 4A , G 1 , as the vertical projection of center of gravity G 1  of the first main body  1  to the installation surface, is illustrated. In the image forming apparatus having the first main body  1 , the supporting leg  20  is attached to the first holding portion  28 A of the bottom plate  28 . By this configuration, G 1  is provided in TR 1 . Specifically, it is preferable that G 1  corresponds to the center of gravity of TR 1 , or G 1  approximately corresponds to the center of gravity of TR 1 , as illustrated  FIG. 4A . Thus, the first main body  1  is set stable on the installation surface S by the supporting legs  20 ,  21 ,  22 . 
     In  FIG. 4B , G 2 , as the vertical projection of center of gravity G 2  of the second main body  100  to the installation surface, is illustrated. By this configuration supporting leg  20  is attached to the second holding portion  28 B of the bottom plate  28  of the second main body  100 , and G 2  is provided in TR 2 . Specifically, it is preferable that G 2  corresponds to the center of gravity of TR 2 , or G 2  approximately corresponds to the center of gravity of the TR 2 , as illustrated  FIG. 4B . Then, the second main body  100  is set stable on the installation surface S by the supporting legs  20 ,  21 ,  22 . 
     As described above, if center of gravity G 1  of the image forming apparatus transforms to center of gravity G 2 , by choosing an appropriate holding portion  28 , both the first main body  1  including the OU and the second main body  100  that does not include the OU may be stable on the installation surface S. 
     A plurality of holding portions  28  that are connectable with the supporting leg  20  are provided to the bottom of the main body  1 . If the number of the holding portions  28  is greater than number of the supporting legs  20 , the attaching position of the supporting leg  20  is selectable. 
     Numerous additional modifications and variations of the supporting leg and the holding portion are possible. 
     In  FIG. 5C , the holding portion  28  includes a through hole  31  in the bottom plate  3 , and the supporting leg  20  is configured to elastically deform. The supporting leg  20  also includes a claw portion  30  inserted into the through hole  31  from the leading edge. When the claw portion goes through the through hole  31 , the claw portion  30  deforms elastically, and after going through the through hole  31 , the claw portion  30  returns to original form by elastic force preventing the supporting leg  20  from being removed. Additionally, in  FIG. 5C , the holding portion  28  includes a screw hole  32  in the bottom plate  3 , and the supporting leg  20  includes a screw axis  33 . The screw axis  33  is twisted into the screw hole  32 , thereby attaching the supporting leg  20  to the bottom plate  3 . 
     Supporting legs  21 ,  22  may also be attached using the methods discussed above in relation to  FIGS. 5A-5D . Additionally, supporting legs  21 ,  22  may be provided as a protruding portion of the bottom plate. Further, one or more of the plurality of supporting legs  21 ,  22  may be detachable. 
     In the case that a user who has the BU buys the OU later, the user can easily change the position of the supporting leg  20  from the position illustrated in  FIG. 4A  to the position illustrated in  FIG. 4B . Additionally, in  FIG. 5A  or  FIG. 5B , since the holding portion is configured as a ditch or hole, the user can attach the holding portion  28  to the supporting leg  20  easily. 
     As illustrated  FIG. 3 , and  FIGS. 5B-5D , a distance H between the bottom plate  3  and bottom of the supporting legs is set to prevent the bottom of the image forming apparatus from hitting the installation surface S. 
     As illustrated in  FIG. 4A  or  FIG. 4B , the first holding portion  28 A and the second holding portion  28 B are configured to be seen by the user. Specifically, the first holding portion  28 A and/or the second holding portion  28 B may be indicated by an eyemark M to attach the supporting leg  20 . The eyemark M is indicated as E, F on the bottom plate  3 . Eyemark E indicates the position that the supporting leg  20  when the first main body  1  does not include the option unit OU, and eyemark F indicates the position that the supporting leg  20  is attached when the first main body  100  includes the option unit OU. 
     By the eyemark M, a manufacturer and/or user can confirm the holding portion  28  to which the supporting leg  20  should be attached. 
     As illustrated in  FIGS. 6-7 , the first main body  1  or the second main body  100  includes a second abdominal plate  34  having a bottom portion to which the supporting legs  21  and  22  are attached, and a first abdominal plate  35  has a bottom portion to which the supporting leg  20  is attached. A first connection plate  36  connects the second abdominal plate  34  and the first abdominal plate  35 , and a second connection plate  37  connects the second abdominal plate  34  and the first abdominal plate  35 . The second abdominal plate  34  and the first abdominal plate  35  may be made by resin, or any other suitable material, and the supporting legs  20 ,  21 ,  22  may be made by metal, or any other suitable material. Since the weight of the first main body  1  or second main body  100  is supported by the second abdominal plate  34  and the first abdominal plate  35 , the distortion of the first main body  1  or second main body  100  may be prevented. 
     In  FIG. 7 , supporting legs  21 ,  22  are attached to a bottom portion of the second abdominal plate  34 , and supporting legs  20 A,  20 B are attached to a bottom portion of the first abdominal plate  35 . 
     An intersection point of a line L 1 , which connects the supporting leg  21  and the supporting leg  22 , with a line L 2 , that goes through g as the vertical projection of center of gravity G and perpendicular to the line L 1  connecting the supporting leg  21  and the supporting leg  22 , is defined as Y. Supporting leg  21  and supporting leg  22  face each other across Y, and are respectively biased to E 1 , E 2  at an end of the second abdominal plate  34 . 
     An intersection point of line L 3 , connecting the supporting leg  20 A and the supporting leg  20 B, with a line L 4 , that goes through g as the vertical projection of center of gravity G and perpendicular to line L 3  connecting the supporting leg  20 A and the supporting leg  20 B, is defined as X. Supporting leg  20 A and supporting leg  20 B face each other across X and are biased to X of the first abdominal plate  35 . 
     Additionally, the supporting legs have the following positional relationships: 
     a distance between the first supporting leg and X is defined as D 1 , 
     a distance between the second supporting leg and X is defined as D 2 , 
     a distance between the third supporting leg and Y is defined as D 3 , 
     a distance between the fourth supporting leg and Y is defined as D 4 , 
     a distance between the first supporting leg and the second supporting leg is defined as D 5 , 
     a distance between the third supporting leg and the fourth supporting leg is defined as D 6 , 
     D 3  is greater than D 1 , 
     D 3  is greater than D 2 , 
     D 4  is greater than D 1 , 
     D 4  is greater than D 2 , and 
     a proportion of D 6  to D 5  is set from 5 to 3. 
     As described above, supporting legs  20 A,  20 B, and  21 ,  22  can make form a triangle including g as the vertical projection of center of gravity G. The first main body  1  and second main body  100  are set stable and distortion may be prevented even if the installation surface is uneven. 
     The substantial triangle including g as the vertical projection of center of gravity G can be applied in case that the center of gravity of the main body is transformed whether the main body includes the option unit on the basic unit or only the basic unit. An example is described as following. 
       FIG. 8  and  FIG. 9  are horizontal views showing a configuration of the square protruding portion  27  having holding portions  28 A,  28 B that hold the supporting legs  21  or  22 , and the first abdominal plate  35  having holding portions  28 C,  28 D, and  28 E that hold the supporting legs  20 A or  20 B. 
     Holding portions  28 A,  28 B, including the square protruding portion illustrated in  FIG. 5 , are provided at the bottom portion of the second abdominal plate  34 , and supporting legs  21 ,  22  are fixed to holding portions  28 A,  28 B. Regardless of whether the image forming apparatus includes the OU, supporting legs  21 ,  22  are fixed to holding portions  28 A,  28 B. Holding portions  28 C,  28 D, and  28 E include the square protruding portion illustrated in  FIG. 5  at the bottom portion of the first abdominal plate  35 . 
     As illustrated  FIG. 8  and  FIG. 9 , supporting legs  20 A,  20 B,  21 , and  22  are indicated with hatching. 
     When the vertical projection of the center of gravity of the image forming apparatus to the installation surface is g 1 , as illustrated in  FIG. 8 , supporting leg  20 A is attached to holding portion  28 C and supporting leg  20 B is attached to holding portion  28 D. 
     When the vertical projection of the center of gravity of the image forming apparatus to installation surface is g 2 , as illustrated in  FIG. 9 , supporting leg  20 A is attached to holding portion  28 E and supporting leg  20 B is attached to holding portion  28 D. 
     When g 1  is transformed to g 2 , supporting leg  20 A is detached from holding portion  28 C and attached to holding portion  28 E. 
     In this embodiment, supporting legs  20 A,  20 B are detached and attached according to the transformation of the vertical projection of the center of gravity. At least one of the supporting legs provided at the first abdominal plate  35  is/are capable of being detached and attached according to the transformation of the vertical projection of the center of gravity. As illustrated in  FIG. 8  and  FIG. 9 , the vertical projection of the center of gravity of the image forming apparatus is g 1  and g 2 , 
     supporting leg  21  and supporting leg  22  face each other across Y; 
     supporting leg  21  and supporting leg  22  are biased to E 1  and E 2 , respectively; 
     supporting leg  20 A and supporting leg  20 B face each other across X; 
     supporting leg  20 A and supporting leg  20 B are biased to Y of the first abdominal plate  35 ; 
     D 3  is greater than D 1 , 
     D 3  is greater than D 2 , 
     D 4  is greater than D 1 , 
     D 4  is greater than D 2 , and 
     a proportion of D 6  to D 5  is set from 5 to 3. 
     As described above, the image forming apparatus having a plurality of supporting legs, is capable of supporting various apparatus configurations. 
     The present invention is capable to be applied to various image forming apparatus, for example an image forming apparatus that forms a black and white image. Numerous additional modifications and variations of the present invention are possible in light of the above disclosure.