Abstract:
A waiting tray is provided at some midpoint of a conveying path, and a sheet is caused to be in a waiting state when a post-process is required. Before performing the post-process, a processing tray receives the sheet conveyed from the waiting tray and the sheet conveyed from a conveying path without passing through the waiting tray. The waiting tray is formed by waiting tray parts which are arranged at a predetermined interval, and a strike-down mechanism is operated. Therefore, a bundle of paper loaded on the waiting tray is caused to fall down on the process tray.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-281784, filed Sep. 28, 2004, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a sheet post-process apparatus, such as a finisher, which is designed for installation at the outlet side of a multi-function periperal (MFP). 
   2. Description of the Related Art 
   An apparatus called “finisher” is known, which receives printed sheets supplied from the MFP and staples them together. In the finisher, the sheets supplied from the MFP are sequentially conveyed to a tray and stapled by a stapler, forming a bundle of sheets. The bundle of sheets is ejected from the apparatus onto a storage tray. 
   Jpn. Pat. Appln. KOKAI Publication No. 6-99070 discloses a finisher. This finisher performs a post-process on sheets. In the post-process, a stapler staples sheets. To process the sheets at the same rate as the MFP processes them, it is necessary to reduce the speed at which sheets are conveyed in the finisher. The finisher therefore has a long sheet-conveying path. 
   In Jpn. Pat. Appln. KOKOKU Publication No. 6-99070, because two sheet paths of a sort path and a non-sort path exist, the number of mechanical parts such as a roller is increased by the sort path. 
   A paper post-process apparatus, which is arranged to retract a jogger stage for jogging the sheets of paper in order to move a bundle of paper onto the storage tray when the process of stapling sheets together with the stapler is finished, is well known (Jpn. Pat. Appln. KOKAI Publication No. 8-217321). 
   BRIEF SUMMARY OF THE INVENTION 
   An object of the invention is to provide the sheet post-process apparatus which can decrease the number of mechanical parts such as the roller to achieve miniaturization and cost reduction of the apparatus. 
   According to an aspect of the invention, there is provided a sheet post-process apparatus comprising: a plurality of rollers configured to receive and convey a sheet conveyed from an MFP main body; a standby tray which is provided at some midpoint of a conveying path, and is configured to cause the sheet conveyed from the roller to be in a waiting state when a post-process is required, the waiting tray including a pair of standby tray parts arranged at a predetermined interval in a transverse direction orthogonal to a sheet conveying direction; a processing tray configured to receive the sheet conveyed from the waiting tray and the sheet conveyed from a conveying path without passing through the waiting tray before performing the post-process; a strike-down mechanism configured to strike the sheet loaded in the waiting tray down on the processing tray; an alignment mechanism configured to align the sheets on the processing tray to form a bundle of sheets; a post-process mechanism configured to perform the post-process of the bundle of sheets aligned on the processing tray; a sheet conveying unit configured to convey the bundle of sheets to which the post-process has been performed from the processing tray; and a storage tray configured to load the conveyed bundle of sheets thereon. 
   Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  is a perspective view of a post-process apparatus according to the invention; 
       FIG. 2  is a top view of the post-process apparatus according to the invention; 
       FIG. 3  is a perspective view illustrating how the waiting tray of the post-process apparatus performs its function; 
       FIG. 4  is a perspective view depicting the sheet-bundle conveying mechanism provided in the post-process apparatus, and explaining how sheets are aligned at longitudinal edges in the post-process apparatus; 
       FIG. 5  is a perspective view showing the mechanism for aligning sheets at their transverse edges; 
       FIG. 6  is a perspective view illustrating how the stapler provided in the post-process apparatus performs its function; 
       FIG. 7  is a sectional view of the post-process apparatus, showing how the first sheet moves from the input rollers to the sheet-feeding roller; 
       FIG. 8  is a sectional view of the apparatus, explaining how the first sheet moves from the sheet-feeding rollers to the waiting tray; 
       FIG. 9  is a sectional view of the apparatus, explaining how the second sheet moves from the sheet-feeding rollers to the waiting tray; 
       FIG. 10  is a view for explaining the operation of active drop in the post-process apparatus according to the embodiment of the invention; 
       FIG. 11  is a sectional view of the apparatus, explaining how the third sheet is conveyed; 
       FIG. 12  is a sectional view of the apparatus, illustrating how the stapler operates; 
       FIG. 13  is a sectional view of the apparatus, explaining how a bundle of sheets moves between the processing tray and the storage tray; 
       FIG. 14  is a view for explaining a strike-down mechanism in the post-process apparatus according to the embodiment of the invention; 
       FIG. 15  is a view for explaining the waiting tray in the post-process apparatus according to the embodiment of the invention; and 
       FIG. 16  is a view for explaining a paper width adjustment mechanism in the post-process apparatus according to the embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An embodiment of this invention will be described, with reference to the accompanying drawings. 
     FIG. 1  is a perspective view of a sheet post-process apparatus according to this invention.  FIG. 2  is a top view of the post-process apparatus. As  FIG. 1  shows, the post-process apparatus comprises a waiting tray  10 , a processing tray  12 , a stapler  14 , a first storage tray  16 , and a second storage tray  18 . 
   The sheet post-process apparatus further comprises a pair of input rollers  22 , a pair of sheet-feeding rollers  24 , and an input-roller motor  26 . The input rollers  22  receive a sheet  20  supplied from an MFP  1  (see  FIG. 7 ) and convey the sheet  20  to the sheet-feeding rollers  24 . The sheet-feeding rollers  24  convey the sheet  20  to the waiting tray  10 . The input-roller motor  26  drives the input rollers  22 . 
   One of the input rollers  22  is an upper input roller  22   a , and the other input roller  22  is a lower input roller  22   b . Likewise, one of the sheet-feeding rollers  24  is an upper sheet-feeding roller, and the other sheet-feeding roller  24  is a lower sheet-feeding roller. 
   The waiting tray  10  includes a pair of waiting tray parts  10   a  and  10   b  having an L-shaped cross section, which are arranged at a predetermined interval as shown in  FIG. 15 . The paper  20  is loaded between the waiting tray parts  10   a  and  10   b . Namely, as shown in  FIG. 15 , the paper  20  is loaded so that transverse sides of the paper  20  get snagged on the waiting tray parts  10   a  and  10   b . A hold portion  10   c  for holding the lowermost portion of the paper loaded on the waiting tray  10  is provided because the waiting tray  10  is obliquely arranged. 
   Widths in the paper  20  conveying directions of the waiting tray  10  and the processing tray  12  are smaller than the width in the conveying direction of the paper  20 . When the paper falls down on the processing tray  12 , the paper  20  is loaded across the processing tray  12  and the storage tray (shown in  FIG. 2 ). 
   Thus, the width along the conveying direction of the paper in the post-process apparatus can be decreased. 
   As shown in  FIG. 14 , a strike-down mechanism  71  for striking the paper  20  down on the processing tray  12  above an intermediate position between the waiting tray parts  10   a  and  10   b . The strike-down mechanism  71  includes a solenoid  72 , a plunger  73  which is sucked and ejected in accordance with magnetic excitation or non-excitation of the solenoid  72 , and an L-shaped strike-down member  74  which is supported while freely rotated about a point A attached to one end of the plunger  73 . The later-mentioned controller  85  controls passage of electric current through the solenoid  72 . 
   As shown in  FIG. 16 , a paper width adjustment mechanism  81  for adjusting the interval between the waiting tray parts  10   a  and  10   b  in accordance with the width of the paper  20  is provided in the waiting tray parts  10   a  and  10   b . The paper width adjustment mechanism  81  includes a rack and pinion mechanism  82  which is coupled to the waiting tray parts  10   a  and  10   b , a stepping motor  84  which controls rotation of a pinion gear  83 , and the controller  85  which controls the rotation of the stepping motor  84 . 
   As shown in  FIG. 3 , when a predetermined number of sheets of paper are stacked in the waiting tray  10 , the plunger  73  is sucked in an arrow direction of  FIG. 14  by magnetically exciting the plunger  73  with the solenoid  72 , which rotates the strike-down member  74  in the arrow direction. As a result, a central portion of the paper  20  loaded on the waiting tray  10  is subject to downward force by the strike-down member  74  and the paper  20  is bent as shown by a broken line in  FIG. 15  to fall down on the processing tray  12  by a self weight. The operation is referred to as active drop. 
   The sheet post-process apparatus has a paper guide  36 , which guides sheets from the MFP  1  to the waiting tray  10  and thence to the processing tray  12 . The paper guide  36  has a paper-pass ceiling. 
   In the processing tray  12 , the sheets are aligned at the longitudinal edges and the transverse edges. The sheets are aligned at their longitudinal edges by a longitudinal-alignment mechanism  38  as is illustrated in  FIG. 4 . More precisely, an upper longitudinal-alignment motor  40  drives the upper longitudinal-alignment rollers  38   a  of the mechanism  38 , and a lower longitudinal-alignment motor  42  drives the lower longitudinal-alignment rollers  38   b  of the mechanism  38 . Driven by the motors  40  and  42 , the rollers  38   a  and  38   b  move the sheets until one longitudinal edge of every sheet abuts on a stopper  45 . Paddles  44  are provided to facilitate the longitudinal alignment. A paddle motor  46  drives the paddles  44 . 
   The sheets are aligned at their transverse edges, too, as is illustrated in  FIG. 5 . More specifically, the transverse alignment is performed by a transverse-alignment mechanism  47  and a transverse-alignment motor  48 . 
   When the number of sheets thus aligned in the processing tray  12  reaches the prescribed value, the stapler  14  starts operating. The stapler  14  is positioned as depicted in  FIG. 6  and controlled by a stapler-driving unit  49 . 
   Controlled by the unit  49 , the stapler  14  staples the sheets together, forming a bundle of sheets. As shown in  FIG. 4 , a transport mechanism  50  transports the bundle of sheets to the first storage tray  16 . Either the first storage tray  16  or the second storage tray  18  is selected when a storage-tray driving unit  52  moves the tray  16  or  18  to a predetermined upper position. 
   How the post-process apparatus according to this invention operates will be explained with reference to  FIGS. 7 to 16 . 
   As  FIG. 7  shows, a sheet  20  conveyed from the MFP  1  is moved from the input rollers  22  to the sheet-feeding rollers  24 , in the direction of the arrow. 
   As is illustrated in  FIG. 8 , the sheet  20 , or the first sheet, is placed on the waiting tray  10 . Then, the waiting-tray rollers  28  move down, in the direction of the arrow, aligning the trailing edge of the first sheet  20  at the rear (i.e., upstream) end  60  of the waiting tray  10 . 
   Then, as shown in  FIG. 9 , a second sheet of paper  20   a  is conveyed to the waiting tray  10 , and the position of the paper  20   a  is aligned by the self weight with reference to the rear end  60  of the waiting tray  10 . Thus, a stack of paper  20   b  including the two sheets of paper  20  and  20   a  are formed in the waiting tray  10 . 
   The solenoid  72  is magnetically excited to suck the plunger  73  in the arrow direction of  FIG. 14 , which rotates the strike-down member  74  in the arrow direction. As a result, the central portion of the stack of paper  20   b  loaded on the waiting tray  10  is subject to the downward force by the strike-down member  74  and the stack of paper  20   b  is bent as shown by the broken line in  FIG. 15  to fall down on the processing tray  12  by the self weight. The stack of paper  20   b  is supplied to the processing tray  12  by the active drop. 
   From a third sheet of paper, when the interval between the waiting tray parts  10   a  and  10   b  is widened larger than the width of the paper  20 , as shown in  FIG. 11 , paper  20   c  is directly supplied from the paper feed roller  24  to the processing tray  12  without passing through the waiting tray  10 , and the paper  20   c  is loaded on the bundle of paper  20   b  of the two sheets of paper to form a bundle of paper  21 . At this point, the longitudinal-alignment mechanism  38  and the transverse-alignment mechanism  47  function so as to perform the alignment of the bundle of paper  21  in the longitudinal and transverse directions. 
   It is desired that the waiting tray  10  and the processing tray  12  be inclined, having their upstream ends at a lower position than their downstream ends. In other words, they should be so positioned that their rear ends  60  and  62  lie at the lowest position. If the trays  10  and  12  are so inclined, the sheets  20  are aligned, due to gravity, at the rear end  60  of the waiting tray  10 , and the bundle  20   b  can be aligned, due to gravity, at the rear end and  62  of the processing tray  12 . 
   As  FIG. 12  shows, the stapler  14  staples the bundle  21  of sheets. Then, the transport mechanism  50  transports the bundle  21  to the storage tray  16  as illustrated in  FIG. 13 . Thus, the post-process ends. 
   When the post-process is not required (non-sort), the interval between the waiting tray parts  10   a  and  10   b  is widened larger than the width of the paper  20 , and the bundle of paper is directly discharged from the waiting tray  10  to the storage tray  16  through the processing tray  12 . 
   In accordance with the embodiment, the paper  20  is discharged through the same paper path in both the sort process in which the post-process is performed and the non-sort process in which the post-process is not required, so that the miniaturization and the cost reduction of the apparatus can be achieved by decreasing the number of mechanical parts such as the roller. 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.