Sheet finishing apparatus

In a sheet finishing apparatus of the present invention, when temporarily loading a plurality of sheets of paper on a standby tray until a processing tray finishes processing, to prevent a sheet of paper loaded first from being pressed out by a sheet of paper ejected later, a chuck for retaining the rear ends of the sheets of paper is installed on the downstream side of the standby tray, and for curled sheets of paper, a standby tray guide and an arm member for suppressing curling of the central part of the sheets of paper are installed, thus matching on the standby tray is stabilized.

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.

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. 1is a perspective view showing the essential section of a sheet finishing apparatus7relating to an embodiment of the present invention, andFIG. 2is a top view showing the essential section of the sheet finishing apparatus relating to an embodiment of the present invention, andFIG. 3is a schematic block diagram showing the sheet finishing apparatus7arranged adjacent to an image forming apparatus5such as a copier.

The sheet finishing apparatus7is basically composed of a standby tray10, a processing tray12, a stapler14, a first paper ejection tray16, and a second paper ejection tray18.

A sheet of paper P, which an image is formed thereon by the image forming apparatus5such as a copier and ejected from a pair of paper ejection rollers6, is received by a pair of inlet rollers22, is supplied to a pair of paper supply rollers24, and is sent from the paper supply rollers24to the standby tray10. The inlet rollers22are driven by an inlet roller motor26. Between the inlet rollers22and the standby tray10, a paper path ceiling36for leading the sheet of paper P to the paper supply rollers24is installed. The inlet rollers22are composed of an upper inlet roller22aand a lower inlet roller22b. The paper supply rollers24are also composed of an upper paper supply roller and a lower paper supply roller. The standby tray10temporarily loads a plurality of sheets of paper P until the processing tray12finishes to process the sheets of paper.

As shown inFIG. 12, on the standby tray10on the rear end side of the sheet of paper P, a standby tray guide11is arranged. The standby tray guide11controls the movement and position of sheets of paper P sent from the paper supply rollers24to the standby tray10.

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 guide11is born rotatably on the side of the standby tray10and the front end thereof is rounded so as to crush the upward curl of the sheet of paper P.

Furthermore, an assist arm13in a lever shape is born rotatably by the mounting shaft of the paper supply rollers24. The assist arm13, to prevent the rear end side of a sheet of paper P conveyed powerfully from the paper supply rollers24from rising, presses it to the standby tray. The side of the assist arm13in 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 inFIG. 13, the standby tray guide11is composed of11aand11bwhich are arranged right and left almost in accordance with the width of the sheet of paper P. Further, the assist arm13composed of four assist arms13a,13b,13c, and13dare installed and arranged between the standby tray guides11aand11bin the drawing. Further, to prevent the assist arms13from variations in movement, the adjacent assist arms13band13cmay be connected.

Under the standby tray10, the processing tray12for loading sheets of paper P dropped and supplied from the standby tray10is arranged.

The processing tray12, while sheets of paper P are stapled by the stapler14which is a processing mechanism for performing the post process, matches and supports the sheets of paper P to be loaded.

As shown inFIG. 7, when a predetermined number of sheets of paper is stored in the standby tray10, standby tray parts10aand10bare opened in the horizontal direction in the drawing by a standby tray motor34and the sheets of paper P are dropped on the processing tray12by their own weight.

As shown inFIG. 4, the stapler14is positioned by a stapler driving unit49and the stapling process is controlled. The processing tray12has a pair of matching rollers; upper vertical matching roller38aand lower vertical matching roller38bshown inFIG. 5for matching a plurality of sheets of paper P dropped and supplied from the standby tray10in the vertical direction which is the conveying direction. The upper and lower vertical matching rollers38aand38bserve as bundle conveying rollers for clamping a sheet bundle T after the end of the stapling process and taking it out from the stapler14. The upper vertical matching roller38ais driven by a vertical matching upper roller motor40and the lower vertical matching roller38bis driven by a vertical matching lower roller motor42.

When sheets of paper P are dropped and supplied onto the processing tray12, at the position where the rear end of each sheet of paper P is dropped, a paddle44rotatable for matching the uppermost sheet of paper P loaded on the processing tray12in the vertical direction is arranged. The paddle44, as shown inFIG. 6, has a receiver44afor receiving sheets of paper P dropped and supplied onto the processing tray12, a tapping portion44bfor tapping down sheets of paper P onto the processing tray12, and a feeder44cfor matching sheets of paper P on the processing tray12and is driven by a paddle motor46. The paddle44is 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 paddle44runs idle.

Therefore, as shown inFIG. 12, to retain the rear end of the first sheet of paper P at the downstream side part of the standby tray10, a chuck15is installed so as to be positioned between the lower paper supply roller24and the paddle44.

At the end of the processing tray12on the side of the stapler14, a stopper45for 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 tray12, a conveying belt50for conveying a sheet bundle T which is stapled and taken out from the stapler14by the upper and lower vertical matching rollers38aand38bto the first or second paper ejection tray16or18is installed. To the conveying belt50, a feeding pawl50afor catching the rear end of the sheet bundle T is attached.

The standby tray10can drop and supply sheets of paper P to the processing tray12and also can convey the sheets of paper P toward the first or second paper ejection tray16or18. Conveying of the sheets of paper P toward the paper ejection trays16and18is executed by a standby tray roller28for matching sheets of paper P making contact with the sheets of paper P on the standby tray10.

The standby tray roller28is controlled to move up and down by a standby tray roller driving source30and is driven to rotate by a standby tray roller motor32.

The standby tray10is arranged at an angle of inclination of θ1so 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 tray16or18is moved up and down by a paper ejection tray driving unit52and either of them is selected. The first or second paper ejection tray16or18, when loading sheets of paper P, is moved up or down at an almost same height as that of the standby tray10or the processing tray12so as to improve the consistency of the posture of sheets of paper P ejected. Further, the first or second paper ejection tray16or18is arranged at an angle of inclination of θ2so 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 inFIGS. 7 and 8, the standby tray10has the pair of tray members10aand10bformed 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 members10aand10b, standby stoppers10cand10dfor controlling the rear end of each sheet of paper P are installed.

The standby tray10is slidden and moved by the standby tray motor34. Between the standby tray10and the processing tray12, when dropping and supplying sheets of paper P from the standby tray10onto the processing tray12, horizontal matching plates47aand47b, shown inFIG. 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 plates47aand47bare formed so as to slide in the direction v in accordance with the width of the sheets of paper P by a horizontal matching motor48.

Next, the operation of the invention will be described. When an image is formed by the image forming apparatus5and a sheet of paper P is supplied from the paper ejection rollers6, the sheet finishing apparatus7performs 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 tray16slides and moves to the position indicated by the dotted line shown inFIG. 3and can load sheets of paper ejected from the standby tray10in consistent good posture. When the post process is not performed, sheets of paper P conveyed from the inlet roller22via the paper path ceiling36to the paper supply rollers24are supplied to the standby tray10by the paper supply rollers24. Then, the sheets of paper P are conveyed by the standby tray roller28moved down onto the standby tray10and rotated in the direction of the arrow f and are ejected to the first paper ejection tray16.

In this way, sheets of paper are sequentially loaded on the first paper ejection tray16. At this time, the first paper ejection tray16is arranged at an angle of inclination of θ2and 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 tray16in a state that it is curved convexly as shown by the dotted line inFIG. 10, the sheet of paper P precedingly loaded on the paper ejection tray16is 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 tray16unless 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 θ2is provided, so that the sheet of paper P drops by its own weight and is matched and loaded on the first paper ejection tray16in 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 tray12will be described. At this time, the standby tray10slides and moves the tray members10aand10brespectively up to the positions indicated by the dotted lines shown inFIG. 11in 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 plates47aand47b, to horizontally match sheets of paper P dropped from the paper supply rollers24, are arranged so that the interval between the horizontal matching plates47aand47bbecomes almost equal to the width of the sheets of paper P. By doing this, the sheets of paper P supplied from the paper supply rollers24are directly dropped and supplied onto the processing tray12unless the conveyance is interrupted by the standby tray10.

At the time of drop and supply, the upper vertical matching roller38ais shifted upward and the receiver44aof the paddle44receives 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 plates47aand47band is matched horizontally. Then, the paddle44rotates in the direction of the arrow o and the rear end of the sheet of paper P drops from the receiver44aand is tapped down onto the processing tray12by the tapping portion44b. Furthermore, the paddle44sends the sheet of paper P in the direction of the arrow q by the feeder44c, and the rear end of the sheet of paper P makes contact with the stopper45, 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 tray12may be executed by the upper vertical matching roller38aby 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 tray12from the paper supply rollers24. When the sheets of paper Preach a predetermined number of sheets, the stapler14staples and bundles the sheets of paper P on the processing tray12at a desired position to form a sheet bundle T. Hereafter, the upper vertical matching roller38amoves down on the sheet bundle, and the sheet bundle T is clamped by the upper vertical matching roller38arotating in the direction of the arrow r and the lower vertical matching roller38brotating in the direction of the arrow s and is conveyed toward the first paper ejection tray16. When the rear end of the sheet bundle T passes the upper and lower vertical matching rollers38aand38b, it is caught by the feeding pawl50aof the conveying belt50rotating in the direction of the arrow t and the bundle is sent onto the first paper ejection tray16.

At this time, the first paper ejection tray16slides and moves from the position indicated by the dotted line inFIG. 3to the position indicated by the solid line. Further, the first paper ejection tray16is arranged at an angle of inclination of θ2and 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 tray16are 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 θ2is provided, so that the sheet bundle T drops by its own weight and is matched and loaded on the first paper ejection tray16in 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 tray12will be described. At this time, the standby tray10slides and moves the tray members10aand10bfrom the positions indicated by the dotted lines shown inFIG. 11respectively 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 inFIG. 11. Further, the standby tray roller28is shifted upward not to disturb the sheets of paper P. Sheets of paper P which are ejected from the image forming apparatus5and supplied by the paper supply rollers24are loaded once on the standby tray10to wait for the processing tray12to become empty.

As shown inFIG. 14A, sheets of paper P conveyed powerfully from the paper supply rollers are stiff, so that the assist arm13and the standby tray guide11are 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 rollers24, as shown inFIG. 14B, the paddle44rotates and assists dropping of the rear end of the sheet of paper P. Then, with respect to the assist arm13and the standby tray guide11, 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 tray10. As a result, the rear end of the first sheet of paper P is retained surely by the chuck15.

The second and subsequent sheets of paper P loaded on the standby tray10, by the standby tray roller28which moves down on the standby tray10and rotates in the opposite direction of the direction of the arrow f, are sent toward the standby stoppers10cand10dand are vertically matched in a state that the rear end of each sheet of paper P is in contact with the standby stoppers10cand10d. Furthermore, the standby tray10is arranged at an angle of inclination of θ1and 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 stoppers10cand10dand the sheets of paper are vertically matched.

Since the sheets of paper P are matched accurately on the standby tray10like this, even if a sheet of paper P is supplied from the paper supply rollers24in the state that it is curved convexly and supplied onto the standby tray10, the sheet of paper P precedingly loaded on the standby tray10is 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 tray16unless the order is disturbed.

When the preceding sheet of paper P on the processing tray12is ejected on the side of the first paper ejection tray16and the processing tray12becomes empty, the standby tray10slides and moves the tray members10aand10brespectively in the direction of the arrow m and the direction of the arrow n from the positions indicated by the solid lines shown inFIG. 11via the positions indicated by the alternate long and short dash lines shown inFIG. 11up to the positions indicated by the dotted lines shown inFIG. 11. By doing this, for example, two sheets of paper P waiting on the standby tray10, when the tray members10aand10breach the positions indicated by the alternate long and short dash lines shown inFIG. 11, are dropped and supplied onto the processing tray12through the interval between the tray members10aand10b. At this time, the interval between the horizontal matching plates47aand47bis made almost equal to the width of the sheets of paper P. Therefore, the sheets of paper P dropped from the standby tray10are matched horizontally with both sides controlled by the horizontal matching plates47aand47b.

The lower side sheet of paper P of the two sheets of paper P dropped on the processing tray12is sent in the direction of the arrow q by the lower vertical matching roller38brotating 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 stopper45, 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 tray12is sent in the direction of the arrow q by the upper vertical matching roller38arotating 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 stopper45, and the vertical matching of the sheet of paper P is completed, and hereafter the upper vertical matching roller38ais shifted upward.

The third and subsequent sheets of paper P ejected from the image forming apparatus5are directly dropped and supplied onto the processing tray12from the interval between the tray members10aand10bunless they wait on the standby tray10. Hereafter, the third and subsequent sheets of paper P are sequentially matched on the sheets of paper P loaded on the processing tray12before the paddle44.

When sheets of paper P loaded on the processing tray12reach a predetermined number of sheets, the sheets of paper P are stapled by the stapler14and a sheet bundle T is formed. Hereafter, the sheet bundle T is conveyed toward the first paper ejection tray16by the upper and lower vertical matching rollers38aand38b, and moreover the rear end thereof is caught by the feeding pawl50aof the conveying belt50, and the bundle is sent onto the first paper ejection tray16, 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 tray10is provided with an angle of inclination of θ1, thus sheets of paper P can be matched by their own weight on the standby tray10, 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 tray10can 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 tray10can be prevented from disturbance. Similarly, the first or second paper ejection tray16or18is provided with an angle of inclination of θ2, thus there is no fear that sheets of paper P or a sheet bundle T loaded precedingly on the first or second paper ejection tray16or18may 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 tray16or18can 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 tray16or18can 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.