Sheet-material associating – Associating or disassociating – Sheet associating
Reexamination Certificate
1998-11-11
2001-07-17
Olszewski, Robert P. (Department: 2167)
Sheet-material associating
Associating or disassociating
Sheet associating
Reexamination Certificate
active
06260837
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sheet postprocessing device which is provided on an image forming apparatus capable of copying, f axing, and printing, and which performs postprocessing operations including stapling on sheets transported from the image forming apparatus before ejection, and particularly concerns a device for stacking sheets on an ejection tray without disarray.
BACKGROUND OF THE INVENTION
In recent years, a copying machine has been combined with an automatic paper feeding device and a sheet postprocessing device so as to realize automatization of copying and postprocessing operations such as stapling and punching on copied sheets. After images have been copied on the sheets and the sheets have been ejected out of the copying machine, the sheet postprocessing device performs postprocessing operations such as stapling and punching for each set of sheets which consists of a predetermined number of sheets.
Here, with regard to the sheet postprocessing device in which, after sheets have been ejected from the copying machine and have been subjected to a stapling operation that is one of post processing operations, the sheets are ejected onto an ejection tray by an ejection roller since, during an ejection, the edge of the set of sheets tends to rub the surface of the set of sheets that has been ejected earlier and stacked onto the ejection tray, the quality of the fixed image on the surface of the stacked sheets may deteriorate.
Further, during the ejection, if the edge of the set of sheets is caught by a staple of the set of sheets which has been ejected and stacked earlier, the sheets are stacked with disarray.
In order to solve the aforementioned problem, for example, Japanese Laid-Open Patent Publication No.192065/1991 (Tokukaihei 3-192065) discloses a conventional sheet postprocessing device.
In the aforementioned sheet postprocessing device, as shown in
FIG. 9
, a set of stapled sheets
101
is ejected from sheet ejecting rollers
102
and stacked onto an ejection tray
103
which is installed on the inside of the sheet postprocessing device.
The sheet postprocessing device is provided with sheet detecting levers
104
that have two kinds of lengths for detecting the position of leading portions of both large and small sheets which have been stacked on the ejection tray
103
, that is, for detecting the highest position of the stacked sheets on the ejection tray
103
. A tray ascending/descending device
106
moves the ejection tray
103
downward so that the highest position of sheets is not more than a fixed line
105
. With this operation, during the ejection, the sets of sheets ejected out of the sheet ejecting rollers
102
are not supposed to contact with sheets which have been stacked earlier.
In the conventional sheet postprocessing device, since the ejection tray
103
is installed on the inside of the sheet postprocessing device, the sheet detecting levers
104
are not exposed outside; however, in the case when the ejection tray
103
is installed on the outside of the sheet post postprocessing device, the sheet detecting levers
104
are exposed outside. Thus, the problem is that the long sheet detecting levers
104
spoil the appearance.
The present invention is devised in order to solve the aforementioned problem. The objective is to provide a sheet postprocessing device which positively prevents an uneven image from occurring and keeps the sheets aligned during a stacking operation, without using any means which spoil the appearance, when the sets of sheets are ejected from the sheet postprocessing device onto the ejection tray.
SUMMARY OF THE INVENTION
In order to solve the aforementioned problem, the postprocessing device of the present invention, which stacks sheets ejected out of the image forming apparatus onto a postprocessing tray and ejects the sheets through ejecting rollers onto an ejection tray after having carried out a postprocessing operation for binding the stacked sheets, is characterized in that the ejecting rollers are provided with a lifting means for lifting the leading portion of the set of bound sheets with regard to the ejecting direction.
With the aforementioned invention, the sheets which have been ejected out of the image forming apparatus are stacked on the postprocessing tray, and after the postprocessing operation has been performed for binding the sheets, the sheets are normally ejected through the ejecting rollers onto the ejection tray in a state in which the set of sheets are bound at the leading portion thereof with regard to the ejecting direction.
Here, the ejecting rollers are provided with a lifting means for lifting the leading portion of the set of bound sheets with regard to the ejecting direction. Therefore, when the set of sheets is ejected through the ejecting rollers, the lifting means lifts the leading portion so that the set of sheets can be ejected without being in contact with the sets of sheets which have been stacked earlier on the ejection tray.
Thus, during the ejection, the leading portion of the set of sheets does not rub the surface of the set of sheets which has been ejected and stacked earlier onto the ejection tray so that it is possible to prevent degradation in the quality of the image which has been fixed on the surface of the set of sheets.
Further, the lifting means is provided on the ejecting rollers; therefore, the lifting means is not exposed outside even in the case when the ejection tray is installed on the outside of the sheet postprocessing device.
Moreover, in the case when the postprocessing operation is a stapling operation, the leading portion of the set of sheets which is being ejected is not caught by a staple of the set of sheets which has been ejected and stacked earlier onto the ejection tray; therefore, it is possible to stack the sets of sheets without disarray.
Therefore, it is possible to provide a sheet postprocessing device which positively prevents an uneven image from occurring and which prevents the edges of the sheets from being uneven during the stacking operation, without using any means which spoil the appearance, when the set of sheets are ejected out of the sheet postprocessing device onto the ejection tray.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4822024 (1989-04-01), Takahashi
patent: 5131641 (1992-07-01), Hidaka
patent: 5320336 (1994-06-01), Asami
patent: 5540421 (1996-07-01), Ohta et al.
patent: 5590871 (1997-01-01), Okabe et al.
patent: 5709376 (1998-01-01), Ushirogata
patent: 5765824 (1998-06-01), Kawanao et al.
patent: 5772198 (1998-06-01), Yamamoto
patent: 5895036 (1999-04-01), Asao
patent: 5911414 (1999-06-01), Kato et al.
patent: 6082725 (2000-07-01), Shinno et al.
patent: 659667A1 (1994-12-01), None
patent: 745547a2 (1996-05-01), None
patent: 3-192065 (1991-08-01), None
patent: 9015770 (1990-12-01), None
patent: 9513236 (1995-05-01), None
Kanezaki Masahiro
Matsuda Mitsuo
Nagata Jinichi
Nanba Toyoaki
Tanaka Tomomi
Olszewski Robert P.
Renner Otto Boisselle & Sklar
Ridley Richard
Sharp Kabushiki Kaisha
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