Sheet-material associating – Associating or disassociating – Sheet associating
Reexamination Certificate
2000-09-29
2001-12-25
Ellis, Christopher P. (Department: 3651)
Sheet-material associating
Associating or disassociating
Sheet associating
C270S058080, C270S058110, C271S303000
Reexamination Certificate
active
06332606
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a finisher for an image forming apparatus, for example a copy machine, printer or similar image forming apparatus, and particularly to a sheet transport system which simultaneously transports plural sheets from an image forming apparatus to an image formed sheet stacker by way of a finisher.
2. Discussion of the Background Art
In a background finisher of an image forming apparatus, the finisher receives and stacks image formed sheets from an image forming apparatus and then carries out various finishing processes on the image formed sheets. As examples of the finishing processes, the finisher can staple, make holes, fold, stamp the image formed sheets, etc.
In a case that a finisher is combined with an automatic document feeder (ADF) in an image forming apparatus, for example, the finisher may receive a second set of image formed sheets after a first set of image formed sheets is stapled and transported to the image formed sheet stacker. However, in this case the total finishing operation time becomes longer than the image forming process time because the finisher system requires both a finishing operation time, such as a time for stapling, and a transporting time for transporting sheets from the finisher to the image formed sheet stacker.
Therefore, as such a finishing time is longer than an image forming time, the image forming operation may be suspended until the finishing operation ends. When the image forming operation is thus suspended, the productivity of the image forming apparatus decreases.
Some attempts to solve this problem involve simultaneously transporting piled plural image formed sheets to a finisher. Specifically, a finisher system may include a plural sheet transport path between an image formed sheet receiver and a finisher. The finisher system can then temporally suspend a part of a set of image formed sheets which are to be finished in the above plural sheet transport path.
One such system is disclosed in Japanese Laid Open Patent Application 5-286619 and as shown in
FIGS. 1 and 2
.
FIG. 1
is a cross-sectional view of this background sheet path system with finisher in which a finisher system
313
includes a first sheet transport path
312
and a second sheet transport path
311
which is longer than the first sheet transport path
312
; these sheet transport paths
311
,
312
are also formed between two pairs of rollers
307
and
305
. The first sheet transport path
312
includes a pair of rollers
316
and the second sheet transport path
311
includes a pair of rollers
315
. These sheet transport paths
311
and
312
branch off after the pair of rollers
305
at an entrance and merge with each other at the pair of rollers
307
at an exit. Furthermore, a path selector
314
is set up at the junction point between the first sheet transport path
312
and the second sheet transport path
311
.
Referring to FIG.
2
(
a
), the finisher system inserts a first sheet
310
a
to the pair of rollers
305
through the sheet guide
308
from an image forming apparatus. The path selector
314
selects the second sheet transport path
311
. The inserted first sheet
310
a
is thereby transported to the second sheet transport path
311
via the path selector
314
by rotation of the pair of rollers
305
.
Referring to FIG.
2
(
b
), while the inserted first sheet
310
a
is passing through the second sheet transport path
311
, the path selector
314
shifts its position to select the first sheet transport path
312
. The pair of rollers
305
then guides a second sheet
310
b
to the first sheet transport path
312
.
Referring to FIG.
2
(
c
), both sheets
310
a
and
310
b
are joined and piled at the entrance to the pair of feeding rollers
307
along each sheet transport path
311
and
312
because each path has a different distance. Simultaneously, the path selector
314
shifts its position to again select the second sheet transport path
311
. A third sheet
310
c
is then fed to the second sheet transport path
311
by way of the path selector
314
by rotation of the pair of rollers
305
.
Referring to FIG.
2
(
d
), the first sheet
310
a
and the second sheet
310
b
are transported at this time. Furthermore, the path selector
314
then shifts its position to select the first sheet transport path
312
. A fourth sheet
310
d
is then fed to the first sheet transport path
312
by way of the path selector
314
by rotation of the pair of rollers
305
while the third sheet
310
c
is transported in the second sheet transport path
311
.
Now referring to
FIG. 3
, another background art system is disclosed in Japanese Laid Open patent application 5-147372, U.S. Pat. No. 5,344,130. In this background art. a finisher
440
receives a first sheet S
1
and transports the first sheet S
1
along a main path
441
c
during a finishing operation for a first set of sheets S on a finishing plate
446
, for example to be stapled by a stapler
449
, as shown in FIG.
3
(
a
). Then, the finisher
440
suspends rotating of a pair of rollers
443
during the finishing operation for the first set of sheets. As a result of suspending rotating of the pair of rollers
443
, the sheet S
1
is also suspended at the pair of rollers
443
.
Referring to FIG.
3
(
b
), a second sheet S
2
is transported along a bypath
441
b
by shifting a deflector
444
. As a result, the finisher
440
is capable of maintaining a time of a finishing time for the first set of sheets S. Sequentially, after the finisher
440
completes the finishing operation for the first set of sheets, the pair of rollers
442
and
443
is synchronously rotated. Finally, sheets S
1
and S
2
are simultaneously fed from main path
441
c
and bypath
441
b
to the finishing plate
446
as shown in FIG.
3
(
c
).
The inventor of the present invention has identified that the above background art systems have the following problems. In the background art system of
FIGS. 1 and 2
, when the finisher system transports the both sheets
310
a,
310
b,
these sheets may reach roller pair
307
with a shifted position (i.e., the first shift
310
a
may be shifted upstream and reach roller pair
307
prior to second sheet
310
b
) in a transporting direction toward the sheet transport paths. As a result, the both sheets
310
a,
310
b
are joined and piled with a shifted position in the transporting direction at roller pair
307
. This sheet transportation with the shifted position may cause of a sheet jam and improper stacking at a finisher. The finisher then may not be capable of carrying out a proper finishing operation.
Furthermore, in the background art system of
FIG. 3
the sheets ejected from the pair of rollers
442
and
443
fall on account of their own weights. Therefore, when the finisher system transports the both sheets S
1
, S
2
with a shifted position in a transporting direction toward the sheet transport paths, the finisher may not be capable of carrying out a proper finishing operation. The both sheets S
1
, S
2
are joined and piled at the pair of rollers
442
and
443
. Therefore, when the sheets S
1
, S
2
have shifted in the transport direction on the finishing plate
446
, the sheets are transported just at a shifted position.
SUMMARY OF THE INVENTION
The present invention has aspects to overcome the above problems encountered in the aforementioned art.
Furthermore, Accordingly, one object of the present invention is to provide a finishing system for an image forming apparatus which can maximize an efficiency of operations.
A more specific object of the present invention is to provide a finishing system for an image forming apparatus which can ensure proper feeding of sheets to a finisher while minimizing operation time.
In one embodiment, the present invention achieves these objectives by providing a finishing system for image formed sheets transported from an image forming apparatus which includes a finisher for finishing the image formed sheets, a direct sheet feeding path for feeding the image formed shee
Ellis Christopher P.
Mackey Patrick
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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