Patent Publication Number: US-7591455-B2

Title: Sheet finishing apparatus

Description:
The present application is a continuation of U.S. application Ser. No. 11/085,625, filed Mar. 22, 2005, the entire contents of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet finishing apparatus for post-processing sheets of paper ejected from an image forming apparatus such as a copier, a printer, or a composite device. 
     2. Description of the Related Art 
     In recent years, there has been an image forming apparatus used in which to perform a post process of sorting and stapling sheets of paper after image forming, a sheet finishing apparatus is installed adjacent to the paper ejection unit of the image forming apparatus body. In such a sheet finishing apparatus, after the end of the post process of a preceding sheet of paper, the post process is performed for a succeeding sheet of paper. To make the succeeding sheet of paper ejected from the image forming apparatus body like this stand by, conventionally, there is an apparatus having a shifting path such as a standby tray installed halfway down the path leading to the stapler. 
     When temporarily loading a plurality of sheets of paper on the standby tray until the process by the processing tray ends, consideration of preventing a sheet of paper loaded first from being pressed out by a succeeding sheet of paper ejected and surely loading a curled sheet of paper in a poor position on the standby tray in good consistency are required. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the essential section of the sheet finishing apparatus relating to an embodiment of the present invention. 
         FIG. 2  is a top view showing the essential section of the sheet finishing apparatus relating to an embodiment of the present invention. 
         FIG. 3  is a schematic block diagram showing the sheet finishing apparatus relating to an embodiment of the present invention. 
         FIG. 4  is a perspective view showing the stapler of the sheet finishing apparatus relating to an embodiment of the present invention. 
         FIG. 5  is a perspective view showing the vertical matching roller relating to an embodiment of the present invention. 
         FIG. 6  is an illustration showing the paddle relating to an embodiment of the present invention. 
         FIG. 7  is a schematic perspective view showing the standby tray and processing tray relating to an embodiment of the present invention. 
         FIG. 8  is a top view showing the standby tray and processing tray relating to an embodiment of the present invention. 
         FIG. 9  is a schematic perspective view showing the horizontal matching plate and conveying belt relating to an embodiment of the present invention. 
         FIG. 10  is an illustration showing the condition that a sheet of paper on the standby tray or paper ejection tray relating to an embodiment of the present invention is pressed out. 
         FIG. 11  is an illustration showing movement of the standby tray relating to an embodiment of the present invention. 
         FIG. 12  is an illustration showing the standby tray guide and assist arm relating to an embodiment of the present invention. 
         FIG. 13  is an illustration showing an arrangement example of the standby tray guide and assist arm relating to an embodiment of the present invention. 
         FIGS. 14A and 14B  are illustrations showing the consistency of the posture of a sheet of paper positioned by the standby tray guide and assist arm on the standby tray. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus of the present invention. 
     Hereinafter, the embodiment of the present invention will be explained in detail with reference to the accompanying drawings. 
     Further, in each drawing, to the same parts, the same numerals are assigned and duplicated explanation omitted.  FIG. 1  is a perspective view showing the essential section of a sheet finishing apparatus  7  relating to an embodiment of the present invention, and  FIG. 2  is a top view showing the essential section of the sheet finishing apparatus relating to an embodiment of the present invention, and  FIG. 3  is a schematic block diagram showing the sheet finishing apparatus  7  arranged adjacent to an image forming apparatus  5  such as a copier. 
     The sheet finishing apparatus  7  is basically composed of a standby tray  10 , a processing tray  12 , a stapler  14 , a first paper ejection tray  16 , and a second paper ejection tray  18 . 
     A sheet of paper P, which an image is formed thereon by the image forming apparatus  5  such as a copier and ejected from a pair of paper ejection rollers  6 , is received by a pair of inlet rollers  22 , is supplied to a pair of paper supply rollers  24 , and is sent from the paper supply rollers  24  to the standby tray  10 . The inlet rollers  22  are driven by an inlet roller motor  26 . Between the inlet rollers  22  and the standby tray  10 , a paper path ceiling  36  for leading the sheet of paper P to the paper supply rollers  24  is installed. The inlet rollers  22  are composed of an upper inlet roller  22   a  and a lower inlet roller  22   b . The paper supply rollers  24  are also composed of an upper paper supply roller and a lower paper supply roller. The standby tray  10  temporarily loads a plurality of sheets of paper P until the processing tray  12  finishes to process the sheets of paper. 
     As shown in  FIG. 12 , on the standby tray  10  on the rear end side of the sheet of paper P, a standby tray guide  11  is arranged. The standby tray guide  11  controls the movement and position of sheets of paper P sent from the paper supply rollers  24  to the standby tray  10 . 
     Generally, when a sheet of paper P printed on one side thereof is set with the printed side down, since ink is shrunk, the sheet of paper P is curled upward. Therefore, the standby tray guide  11  is born rotatably on the side of the standby tray  10  and the front end thereof is rounded so as to crush the upward curl of the sheet of paper P. 
     Furthermore, an assist arm  13  in a lever shape is born rotatably by the mounting shaft of the paper supply rollers  24 . The assist arm  13 , to prevent the rear end side of a sheet of paper P conveyed powerfully from the paper supply rollers  24  from rising, presses it to the standby tray. The side of the assist arm  13  in contact with the sheet of paper P is formed slightly heavily so as to surely prevent the sheet of paper P from unexpected movement. 
     As shown in  FIG. 13 , the standby tray guide  11  is composed of  11   a  and  11   b  which are arranged right and left almost in accordance with the width of the sheet of paper P. Further, the assist arm  13  composed of four assist arms  13   a ,  13   b ,  13   c , and  13   d  are installed and arranged between the standby tray guides  11   a  and  11   b  in the drawing. Further, to prevent the assist arms  13  from variations in movement, the adjacent assist arms  13   b  and  13   c  may be connected. 
     Under the standby tray  10 , the processing tray  12  for loading sheets of paper P dropped and supplied from the standby tray  10  is arranged. 
     The processing tray  12 , while sheets of paper P are stapled by the stapler  14  which is a processing mechanism for performing the post process, matches and supports the sheets of paper P to be loaded. 
     As shown in  FIG. 7 , when a predetermined number of sheets of paper is stored in the standby tray  10 , standby tray parts  10   a  and  10   b  are opened in the horizontal direction in the drawing by a standby tray motor  34  and the sheets of paper P are dropped on the processing tray  12  by their own weight. 
     As shown in  FIG. 4 , the stapler  14  is positioned by a stapler driving unit  49  and the stapling process is controlled. The processing tray  12  has a pair of matching rollers; upper vertical matching roller  38   a  and lower vertical matching roller  38   b  shown in  FIG. 5  for matching a plurality of sheets of paper P dropped and supplied from the standby tray  10  in the vertical direction which is the conveying direction. The upper and lower vertical matching rollers  38   a  and  38   b  serve as bundle conveying rollers for clamping a sheet bundle T after the end of the stapling process and taking it out from the stapler  14 . The upper vertical matching roller  38   a  is driven by a vertical matching upper roller motor  40  and the lower vertical matching roller  38   b  is driven by a vertical matching lower roller motor  42 . 
     When sheets of paper P are dropped and supplied onto the processing tray  12 , at the position where the rear end of each sheet of paper P is dropped, a paddle  44  rotatable for matching the uppermost sheet of paper P loaded on the processing tray  12  in the vertical direction is arranged. The paddle  44 , as shown in  FIG. 6 , has a receiver  44   a  for receiving sheets of paper P dropped and supplied onto the processing tray  12 , a tapping portion  44   b  for tapping down sheets of paper P onto the processing tray  12 , and a feeder  44   c  for matching sheets of paper P on the processing tray  12  and is driven by a paddle motor  46 . The paddle  44  is made of rubber and is elastic. 
     When temporarily loading a plurality of sheets of paper P on the standby tray until the process by the processing tray ends, a sheet of paper loaded first must be prevented from being pressed out by a succeeding sheet of paper ejected. Further, when a sheet of paper P is curled upward, the paddle  44  runs idle. 
     Therefore, as shown in  FIG. 12 , to retain the rear end of the first sheet of paper P at the downstream side part of the standby tray  10 , a chuck  15  is installed so as to be positioned between the lower paper supply roller  24  and the paddle  44 . 
     At the end of the processing tray  12  on the side of the stapler  14 , a stopper  45  for making contact with the rear end of each sheet of paper P and controlling the rear end position is installed. Almost at the center of the processing tray  12 , a conveying belt  50  for conveying a sheet bundle T which is stapled and taken out from the stapler  14  by the upper and lower vertical matching rollers  38   a  and  38   b  to the first or second paper ejection tray  16  or  18  is installed. To the conveying belt  50 , a feeding pawl  50   a  for catching the rear end of the sheet bundle T is attached. 
     The standby tray  10  can drop and supply sheets of paper P to the processing tray  12  and also can convey the sheets of paper P toward the first or second paper ejection tray  16  or  18 . Conveying of the sheets of paper P toward the paper ejection trays  16  and  18  is executed by a standby tray roller  28  for matching sheets of paper P making contact with the sheets of paper P on the standby tray  10 . 
     The standby tray roller  28  is controlled to move up and down by a standby tray roller driving source  30  and is driven to rotate by a standby tray roller motor  32 . 
     The standby tray  10  is arranged at an angle of inclination of θ 1  so as to support sheets of paper P in a state that the front end of each sheet of paper P is positioned higher than the rear end thereof. The first or second paper ejection tray  16  or  18  is moved up and down by a paper ejection tray driving unit  52  and either of them is selected. The first or second paper ejection tray  16  or  18 , when loading sheets of paper P, is moved up or down at an almost same height as that of the standby tray  10  or the processing tray  12  so as to improve the consistency of the posture of sheets of paper P ejected. Further, the first or second paper ejection tray  16  or  18  is arranged at an angle of inclination of θ 2  so as to support sheets of paper P in a state that the front end of each sheet of paper P is positioned higher than the rear end thereof. 
     As shown in  FIGS. 7 and 8 , the standby tray  10  has the pair of tray members  10   a  and  10   b  formed so as to project from the wall surface thereof, receives each sheet of paper P by sliding in accordance with the width of the sheet of paper P, and supports both sides of the sheet of paper P. On the tray members  10   a  and  10   b , standby stoppers  10   c  and  10   d  for controlling the rear end of each sheet of paper P are installed. 
     The standby tray  10  is slidden and moved by the standby tray motor  34 . Between the standby tray  10  and the processing tray  12 , when dropping and supplying sheets of paper P from the standby tray  10  onto the processing tray  12 , horizontal matching plates  47   a  and  47   b , shown in  FIG. 9 , for horizontally matching the sheets of paper P to prevent them from being disordered in the horizontal direction perpendicular to the conveying direction are installed. The horizontal matching plates  47   a  and  47   b  are formed so as to slide in the direction v in accordance with the width of the sheets of paper P by a horizontal matching motor  48 . 
     Next, the operation of the invention will be described. When an image is formed by the image forming apparatus  5  and a sheet of paper P is supplied from the paper ejection rollers  6 , the sheet finishing apparatus  7  performs a different operation depending on execution of the post process of the sheet of paper P or no execution thereof, or during execution of the post process of the preceding sheet of paper P or end of the post process. 
     When the post process is not performed, for example, the first paper ejection tray  16  slides and moves to the position indicated by the dotted line shown in  FIG. 3  and can load sheets of paper ejected from the standby tray  10  in consistent good posture. When the post process is not performed, sheets of paper P conveyed from the inlet roller  22  via the paper path ceiling  36  to the paper supply rollers  24  are supplied to the standby tray  10  by the paper supply rollers  24 . Then, the sheets of paper P are conveyed by the standby tray roller  28  moved down onto the standby tray  10  and rotated in the direction of the arrow f and are ejected to the first paper ejection tray  16 . 
     In this way, sheets of paper are sequentially loaded on the first paper ejection tray  16 . At this time, the first paper ejection tray  16  is arranged at an angle of inclination of θ 2  and the front end of each sheet of paper is positioned higher than the rear end thereof, so that for example, even if a sheet of paper P is ejected onto the first paper ejection tray  16  in a state that it is curved convexly as shown by the dotted line in  FIG. 10 , the sheet of paper P precedingly loaded on the paper ejection tray  16  is not pressed out by contact with the front end of the succeeding sheet of paper P. Namely, the ejected sheet of paper P is sequentially loaded on the first paper ejection tray  16  unless the order is disturbed. Further, even if the preceding sheet of paper P is slightly shifted by being pressed by the succeeding sheet of paper P, the angle of inclination θ 2  is provided, so that the sheet of paper P drops by its own weight and is matched and loaded on the first paper ejection tray  16  in the state that the rear end is properly arranged, and the ejection process of the sheets of paper P is completed. 
     Next, a case that the stapling process which is the post process is to be performed and there is no preceding sheet of paper P during execution of the stapling process on the processing tray  12  will be described. At this time, the standby tray  10  slides and moves the tray members  10   a  and  10   b  respectively up to the positions indicated by the dotted lines shown in  FIG. 11  in the direction of the arrow m and the direction of the arrow n and opens the drop and supply path of sheets of paper P. Further, the horizontal matching plates  47   a  and  47   b , to horizontally match sheets of paper P dropped from the paper supply rollers  24 , are arranged so that the interval between the horizontal matching plates  47   a  and  47   b  becomes almost equal to the width of the sheets of paper P. By doing this, the sheets of paper P supplied from the paper supply rollers  24  are directly dropped and supplied onto the processing tray  12  unless the conveyance is interrupted by the standby tray  10 . 
     At the time of drop and supply, the upper vertical matching roller  38   a  is shifted upward and the receiver  44   a  of the paddle  44  receives the rear end of each sheet of paper P. The sheet of paper P drops in a state that both sides thereof are in contact with the horizontal matching plates  47   a  and  47   b  and is matched horizontally. Then, the paddle  44  rotates in the direction of the arrow o and the rear end of the sheet of paper P drops from the receiver  44   a  and is tapped down onto the processing tray  12  by the tapping portion  44   b . Furthermore, the paddle  44  sends the sheet of paper P in the direction of the arrow q by the feeder  44   c , and the rear end of the sheet of paper P makes contact with the stopper  45 , and the matching of the sheet of paper P in the vertical direction is completed. Further, the vertical matching of sheets of paper P on the processing tray  12  may be executed by the upper vertical matching roller  38   a  by moving it up and down each time. 
     In this way, the sheets of paper P with an image formed thereon are sequentially matched in the horizontal direction and vertical direction and are loaded directly on the processing tray  12  from the paper supply rollers  24 . When the sheets of paper Preach a predetermined number of sheets, the stapler  14  staples and bundles the sheets of paper P on the processing tray  12  at a desired position to form a sheet bundle T. Hereafter, the upper vertical matching roller  38   a  moves down on the sheet bundle, and the sheet bundle T is clamped by the upper vertical matching roller  38   a  rotating in the direction of the arrow r and the lower vertical matching roller  38   b  rotating in the direction of the arrow s and is conveyed toward the first paper ejection tray  16 . When the rear end of the sheet bundle T passes the upper and lower vertical matching rollers  38   a  and  38   b , it is caught by the feeding pawl  50   a  of the conveying belt  50  rotating in the direction of the arrow t and the bundle is sent onto the first paper ejection tray  16 . 
     At this time, the first paper ejection tray  16  slides and moves from the position indicated by the dotted line in  FIG. 3  to the position indicated by the solid line. Further, the first paper ejection tray  16  is arranged at an angle of inclination of θ 2  and the front end of each sheet of paper is positioned higher than the rear end thereof, so that the sheets of paper P of the bundle precedingly sent onto the first paper ejection tray  16  are not pressed out by contact with the front end of the succeeding sheet bundle T. Further, even if the preceding sheet bundle T is slightly shifted by the succeeding sheets of paper P, the angle of inclination θ 2  is provided, so that the sheet bundle T drops by its own weight and is matched and loaded on the first paper ejection tray  16  in the state that the rear ends are properly arranged, and the stapling process of the sheets of paper P is completed. 
     Next, a case that the stapling process which is the post process is to be performed and a preceding sheet of paper P during execution of the stapling process remains on the processing tray  12  will be described. At this time, the standby tray  10  slides and moves the tray members  10   a  and  10   b  from the positions indicated by the dotted lines shown in  FIG. 11  respectively in the opposite direction of the direction of the arrow m and the opposite direction of the direction of the arrow n and can support the sheets of paper P in the positions indicated by the solid lines shown in  FIG. 11 . Further, the standby tray roller  28  is shifted upward not to disturb the sheets of paper P. Sheets of paper P which are ejected from the image forming apparatus  5  and supplied by the paper supply rollers  24  are loaded once on the standby tray  10  to wait for the processing tray  12  to become empty. 
     As shown in  FIG. 14A , sheets of paper P conveyed powerfully from the paper supply rollers are stiff, so that the assist arm  13  and the standby tray guide  11  are rotated and moved upward (in the clockwise direction in the drawing) Therefore, the sheets of paper P move forward so as to be conveyed as linearly as possible. When the rear end of a sheet of paper P comes off the paper supply rollers  24 , as shown in  FIG. 14B , the paddle  44  rotates and assists dropping of the rear end of the sheet of paper P. Then, with respect to the assist arm  13  and the standby tray guide  11 , the heavy front ends are in contact with the sheet of paper P, so that the rear end of the sheet of paper P is immediately pressed against the standby tray  10 . As a result, the rear end of the first sheet of paper P is retained surely by the chuck  15 . 
     The second and subsequent sheets of paper P loaded on the standby tray  10 , by the standby tray roller  28  which moves down on the standby tray  10  and rotates in the opposite direction of the direction of the arrow f, are sent toward the standby stoppers  10   c  and  10   d  and are vertically matched in a state that the rear end of each sheet of paper P is in contact with the standby stoppers  10   c  and  10   d . Furthermore, the standby tray  10  is arranged at an angle of inclination of θ 1  and the front end of each sheet of paper is positioned higher than the rear end thereof, so that the rear end of each sheet of paper P makes contact with the standby stoppers  10   c  and  10   d  and the sheets of paper are vertically matched. 
     Since the sheets of paper P are matched accurately on the standby tray  10  like this, even if a sheet of paper P is supplied from the paper supply rollers  24  in the state that it is curved convexly and supplied onto the standby tray  10 , the sheet of paper P precedingly loaded on the standby tray  10  is not pressed out by contact with the front end of the succeeding sheet of paper P. Namely, the supplied sheet of paper P is sequentially loaded on the first paper ejection tray  16  unless the order is disturbed. 
     When the preceding sheet of paper P on the processing tray  12  is ejected on the side of the first paper ejection tray  16  and the processing tray  12  becomes empty, the standby tray  10  slides and moves the tray members  10   a  and  10   b  respectively in the direction of the arrow m and the direction of the arrow n from the positions indicated by the solid lines shown in  FIG. 11  via the positions indicated by the alternate long and short dash lines shown in  FIG. 11  up to the positions indicated by the dotted lines shown in  FIG. 11 . By doing this, for example, two sheets of paper P waiting on the standby tray  10 , when the tray members  10   a  and  10   b  reach the positions indicated by the alternate long and short dash lines shown in  FIG. 11 , are dropped and supplied onto the processing tray  12  through the interval between the tray members  10   a  and  10   b . At this time, the interval between the horizontal matching plates  47   a  and  47   b  is made almost equal to the width of the sheets of paper P. Therefore, the sheets of paper P dropped from the standby tray  10  are matched horizontally with both sides controlled by the horizontal matching plates  47   a  and  47   b.    
     The lower side sheet of paper P of the two sheets of paper P dropped on the processing tray  12  is sent in the direction of the arrow q by the lower vertical matching roller  38   b  rotating in the opposite direction of the direction of the arrow s, and the rear end of the sheet of paper P makes contact with the stopper  45 , and the vertical matching of the sheet of paper P is completed. The upper side sheet of paper P of the two sheets of paper P dropped on the processing tray  12  is sent in the direction of the arrow q by the upper vertical matching roller  38   a  rotating in the opposite direction of the direction of the arrow r, and the rear end of the sheet of paper P makes contact with the stopper  45 , and the vertical matching of the sheet of paper P is completed, and hereafter the upper vertical matching roller  38   a  is shifted upward. 
     The third and subsequent sheets of paper P ejected from the image forming apparatus  5  are directly dropped and supplied onto the processing tray  12  from the interval between the tray members  10   a  and  10   b  unless they wait on the standby tray  10 . Hereafter, the third and subsequent sheets of paper P are sequentially matched on the sheets of paper P loaded on the processing tray  12  before the paddle  44 . 
     When sheets of paper P loaded on the processing tray  12  reach a predetermined number of sheets, the sheets of paper P are stapled by the stapler  14  and a sheet bundle T is formed. Hereafter, the sheet bundle T is conveyed toward the first paper ejection tray  16  by the upper and lower vertical matching rollers  38   a  and  38   b , and moreover the rear end thereof is caught by the feeding pawl  50   a  of the conveying belt  50 , and the bundle is sent onto the first paper ejection tray  16 , and the stapling process of the sheets of paper P is completed. 
     In this embodiment structured like this, there is no need to install an exclusive path for sheets of paper requiring no post process, so that the cost of the sheet finishing apparatus can be decreased. Further, the time up to paper ejection can be shortened compared with paper ejection via the processing tray. 
     The standby tray  10  is provided with an angle of inclination of θ 1 , thus sheets of paper P can be matched by their own weight on the standby tray  10 , and moreover there is no fear that sheets of paper P loaded precedingly may be pressed out by succeeding sheets of paper P, and the consistent posture of the sheets of paper P on the standby tray  10  can be enhanced, and the sheets of paper P can be prevented from jamming, and moreover the loading order of the sheets of paper P on the standby tray  10  can be prevented from disturbance. Similarly, the first or second paper ejection tray  16  or  18  is provided with an angle of inclination of θ 2 , thus there is no fear that sheets of paper P or a sheet bundle T loaded precedingly on the first or second paper ejection tray  16  or  18  may be pressed out by succeeding sheets of paper P or sheet bundle T, and the consistent posture of the sheets of paper P on the first or second paper ejection tray  16  or  18  can be enhanced, and the sheets of paper P can be prevented from jamming, and moreover the loading order of the sheets of paper P or sheet bundle T on the first or second paper ejection tray  16  or  18  can be prevented from disturbance. 
     Further, in the present invention, the post process performed for sheets of paper loaded on the processing tray is the stapling process. However, the post process is not limited to the stapling process and for example, the post process such as a hole punching (hole boring) process performed for sheets of paper is not questionable. In this case, one sheet of paper instead of a plurality of sheets of paper may be loaded unquestionably on the processing tray. Further, needless to say, for a post processing apparatus having such a post processing mechanism, the present invention produces an effect. 
     Although exemplary embodiments of the present invention have been shown and described, it will be apparent to those having ordinary skill in the art that a number of changes, modifications, or alterations to the invention as described herein may be made, none of which depart from the spirit of the present invention. All such changes, modifications, and alterations should therefore be seen as within the scope of the present invention.