Sheet-material associating – Associating and folding – Stapling or stitching
Reexamination Certificate
2001-09-18
2004-03-30
Mackey, Patrick (Department: 3651)
Sheet-material associating
Associating and folding
Stapling or stitching
C370S902000, C370S902000, C399S410000, C493S444000, C493S384000, C412S018000
Reexamination Certificate
active
06712349
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sheet processing apparatus, a sheet processing system, and a sheet processing method for processing sheets such as stapling sheets, punching sheets, and folding sheets, and relates to the sheet processing apparatus, the sheet processing system, and the sheet processing method which are independent as a sheet processing apparatus, are integrated into a sheet output apparatus such as a copying machine, a printer, a facsimile, or a printing press, or are attachingly installed on a sheet output apparatus for realizing individual features such as stapling, punching, and folding.
BACKGROUND OF THE INVENTION
Conventionally, different types of sheet processing apparatuses for stapling, punching for filing, and folding after stapling sheets on which images are recorded with an image forming apparatus such as a copying machine, a printer or a facsimile have been proposed.
As Japanese Patent Laid-open No. Hei 10-279163 and Hei 11-193162 disclose, sheet processing apparatuses having features of stapling and folding multiple sheets at the center have been well known. These sheet processing apparatuses are constituted in such a manner that they staple a sheet bundle at the center in a conveying direction for example, then fold the sheet bundle into two at the center in conveying direction, and discharge sheet folded at the center on a stacking tray with discharging rollers.
This type of sheet processing apparatus with a simple book binding feature (sheet post-processing apparatus), which staples a sheet bundle at the center and folds the sheet bundle into two, stacks a sheet bundle folded into two on a tray in such a manner that a part where the sheet bundle is stapled and folded faces toward a sheet conveying direction, or, in other words, the part where the sheet bundle is stapled and folded is placed on a farther side from a main unit of the sheet post-processing apparatus when the sheet post-processing apparatus staples a sheet bundle at the center, and discharges and stacks the sheet bundle folded into two. When the sheet bundle stapled and folded at the center is stacked in such a manner that the part stapled and folded at the center is placed on the farther side from the main unit of sheet post-processing apparatus, both ends of the sheet bundle, which are not folded, bulge.
Though the tray is generally tilted upward on the downstream side of sheet discharging direction, as the number of stacked sheet bundles increases, the both ends of sheet bundle, which are not folded, bulge, a volume on a side of the sheet bundle, which is generally lower, increases, and a sheet bundle stacking face on the downstream side of sheet discharging direction becomes lower.
When a sheet bundle is discharged on the sheet bundle stacking face in the state tiled downward on the front side, the sheet bundle falls down from the sheet bundle stacking face, and is not stacked on the stacking tray properly. To avoid this problem, it is required to limit the stacked amount. When the stacked amount is limited in this way, the image forming is suspended at a processed number of sheets corresponding to that stacked amount, leading to a decrease of the processing efficiency. Since the amount of bulge depends on the thickness, the number, or the flexibility of a sheet bundle to be folded into two, even if the stacked number is limited, a sheet bundle may not be stacked on the tray.
When the tray is placed horizontally in a conventional apparatus, the tendency of tilting downward on the front side increases, and the stacked amount is decreased accordingly. To avoid this problem, a sheet pressing arm, which has a fulcrum on an upper side of a sheet discharging opening, and presses a sheet bundle at a free end, is provided.
However, with this type of sheet pressing arm, an area to be pressed is limited by a relationship between length of the arm and an installed position of the arm, and the stacked amount of sheets does not increase largely.
Also, since a contact with a top face of sheet bundles is close to a point contact or a line contact, the sheet bundles are not pressed sufficiently, and the bundles are stacked while they are in bulged state. Thus the stacked amount of sheet bundles is limited.
Also, a conventional example is provided with a dedicated stacking tray for stacking sheet bundles which are stapled at the center and then folded into two. Also a dedicated slope for this tray (such as horizontal slope) is set and fixed. Providing this type of dedicated tray increases the complexity of mechanism of the entire sheet post-processing apparatus, and it is not avoidable that the cost increases accordingly. A space for installing a dedicated tray is also required, thereby increasing the entire size of apparatus, resulting in never meeting a requirement of space saving and downsizing.
As shown in
FIG. 36
, when a pair of rollers
451
and
452
discharge a sheet bundle
700
in such a manner that a front end F on a folded side faces the a stacking tray
301
whose downstream side in a sheet discharging direction tilts upward after the sheet bundle is stapled and folded at the center, the position of a bulged part depends on the size of sheet bundle
700
, the stacked states are not aligned depending on where the bulged part is generated on the sheet bundle
700
, the stacked state also becomes unstable in this case, and an incident that the sheet bundle
700
falls from the stacking tray
301
occurs. Thus, the stacked amount does not increase.
The present invention is made in view of these problems, and the purpose is to provide a sheet processing apparatus stacking more sheet bundles which are stapled at the center and folded into two.
An alternative purpose of the present invention is to provide a sheet processing apparatus whose sheet discharging tray is shared by standard sheets which are not folded into two.
Another alternative purpose of the present invention is to provide a sheet processing apparatus which stacks sheet bundles folded into two without increasing the size of apparatus.
Another alternative purpose of the present invention is to provide an image forming system comprising this type of sheet processing apparatus and an image forming apparatus.
Another alternative purpose of the present invention is to provide a sheet processing method which stacks more sheet bundles stapled at the center and folded into two.
SUMMARY OF THE INVENTION
To attain the purposes described before, the present invention provides a sheet processing apparatus comprising a center-stapling mean for stapling the center of a sheet bundle conveyed from a sheet output apparatus, a center-folding mean for folding the stapled sheet bundle into two, a discharging mean for discharging the sheet bundle folded into two in such a manner that the side folded into two is discharged first, a turning-over mean for turning over a sheet bundle discharged from the discharging mean so that the side folded at the center is oriented to upstream side in sheet conveying direction, and a stacking tray for stacking a sheet or sheet bundle discharged from the discharging mean and turned over by the turning over mean.
The turning-over mean comprises a guide plate for forcing the front side of a sheet bundle discharged from the discharging mean orient downward for discharging. The guide plate is urged toward a closing direction with a predetermined force, and the maximum opening of guide plate is set to a predetermined angle. The guide plate is closed, and retracts to or beyond a face flush with a rear end fence with which a rear end side of a sheet bundle is in contact for a standard discharging without folding a sheet bundle into two, thereby eliminating an interference when the sheet stacking tray moves up/down. It is preferable to provide a detecting mean for detecting an open/closed state of the guide plate.
The turning-over mean may comprise a mean for changing an angle of the stacking tray in such a manner that the angle of stacking tray is steeper than that for the standard discharging
Mackey Patrick
Ricoh & Company, Ltd.
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