U.S. patent application number 11/614182 was filed with the patent office on 2007-06-21 for sheet post-processing apparatus and sheet post-processing method.
This patent application is currently assigned to TOSHIBA TEC KABUSHIKI KAISHA. Invention is credited to Yoshiaki Sugizaki, Hiroyuki Taki, Yasunobu Terao, Mikio Yamamoto.
Application Number | 20070138729 11/614182 |
Document ID | / |
Family ID | 38172553 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070138729 |
Kind Code |
A1 |
Terao; Yasunobu ; et
al. |
June 21, 2007 |
SHEET POST-PROCESSING APPARATUS AND SHEET POST-PROCESSING
METHOD
Abstract
To provide a sheet post-processing apparatus for stapling and
ejecting sheets conveyed from an image forming apparatus. The sheet
post-processing apparatus comprises a processing tray to load the
sheets conveyed from the image forming apparatus and a stapler to
staple a sheet bundle of the sheets loaded on the processing tray,
and the stapled sheet bundles are led to a sheet receiving tray and
are ejected so that the stapling positions of the plurality of
sheet bundles loaded on the sheet receiving tray are shifted from
each other at each upper and lower stages.
Inventors: |
Terao; Yasunobu;
(Shinagawa-ku, Tokyo, JP) ; Yamamoto; Mikio;
(Shinagawa-ku, Tokyo, JP) ; Sugizaki; Yoshiaki;
(Shinagawa-ku, Tokyo, JP) ; Taki; Hiroyuki;
(Shinagawa-ku, Tokyo, JP) |
Correspondence
Address: |
AMIN, TUROCY & CALVIN, LLP
1900 EAST 9TH STREET, NATIONAL CITY CENTER
24TH FLOOR,
CLEVELAND
OH
44114
US
|
Assignee: |
TOSHIBA TEC KABUSHIKI
KAISHA
2-17-2, Higashigotanda
Tokyo
JP
141-8664
|
Family ID: |
38172553 |
Appl. No.: |
11/614182 |
Filed: |
December 21, 2006 |
Current U.S.
Class: |
270/58.09 |
Current CPC
Class: |
B65H 2301/4219 20130101;
B65H 31/3081 20130101; B65H 2301/42266 20130101; B42C 1/12
20130101 |
Class at
Publication: |
270/058.09 |
International
Class: |
B65H 37/04 20060101
B65H037/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2005 |
JP |
2005-368279 |
Claims
1. A sheet post-processing apparatus for stapling and ejecting
sheets conveyed from an image forming apparatus, comprising:
processing tray means for loading the sheets conveyed from the
image forming apparatus; stapling means for stapling a sheet bundle
of the sheets loaded on the processing tray means; and ejection
means for leading the stapled sheet bundle to a sheet receiving
tray and ejecting the same so as to shift the stapling positions of
the plurality of sheet bundles loaded on the sheet receiving tray
from each other at each upper and lower stages.
2. A sheet post-processing apparatus to staple and eject sheets
conveyed from an image forming apparatus, comprising: a processing
tray to load the sheets conveyed from the image forming apparatus;
a stapler to staple a sheet bundle of the sheets loaded on the
processing tray; and an ejection unit to leading the stapled sheet
bundle to a sheet receiving tray and eject the same so as to shift
the stapling positions of the sheet bundles loaded on the sheet
receiving tray from each other at each upper and lower stages.
3. The apparatus according to claim 2 further comprising: an
aligning unit including a pair of aligning plates to align the
sheets loaded on the processing tray from both sides in the
conveying direction to move the pair of aligning plates to a normal
aligning position and a position shifted from the normal aligning
position by a predetermined distance in a direction perpendicular
to the conveying direction, wherein the stapler can move along
edges in the conveying direction of the sheets aligned by the
aligning unit and staple the conveyed sheets at several places at
the normal aligning position, and the sheet ejection unit leads the
sheet bundles stapled onto the sheet receiving tray in the state
that the sheet bundles are shifted from each other in the direction
perpendicular to the conveying direction by the aligning unit.
4. The apparatus according to claim 3, wherein: the aligning unit
can move the pair of aligning plates to the normal aligning
position and at a predetermined distance around the normal aligning
position in a first direction perpendicular to the conveying
direction and in a second direction opposite to the first
direction, and the ejection unit leads the sheet bundles stapled at
the normal aligning position onto the sheet receiving tray by
shifting them alternately in the first direction and second
direction.
5. The apparatus according to claim 3, wherein: the stapler, when
the pair of aligning plates are at the normal aligning position,
moves in the first direction, and at a first position and a second
position in the movement direction, staples sheets conveyed, and
moves next the stapler in the opposite direction of the first
direction and at the second position and first position in the
movement direction, staples sheets conveyed next.
6. The apparatus according to claim 3, wherein assuming an interval
between stapling positions by the stapler as L1 and the
predetermined distance of moving of the aligning unit from the
normal aligning position as L2, L2<L1/2.
7. The apparatus according to claim 3, wherein positions stapled by
the stapler are at least two places along the edges of the
sheets.
8. The apparatus according to claim 3, wherein the aligning unit
includes, in addition to the pair of aligning plates to align the
sheets loaded on the processing tray from both sides in the
conveying direction, second aligning unit to aligning the edges of
the sheets in the conveying direction.
9. The apparatus according to claim 8, wherein the second aligning
unit includes a stopper installed on the stapler to stop the edges
of the sheets in the conveying direction.
10. The apparatus according to claim 2, wherein the stapler staples
a first sheet bundle loaded on the processing tray at a first
stapling position and staples a next second sheet bundle at a
second stapling position shifted from the first stapling position,
and the ejection unit ejects the first sheet bundle and second
sheet bundle onto the sheet receiving tray.
11. The apparatus according to claim 10, wherein the first sheet
bundle and second sheet bundle are stacked on the sheet receiving
tray in the state that both sides thereof in the conveying
direction are aligned.
12. The apparatus according to claim 10, wherein positions stapled
by the stapler are at least two places along the edges of the
sheets.
13. The apparatus according to claim 10, wherein a position stapled
by the stapler is one place of a corner of each sheet.
14. A sheet post-processing method for stapling and ejecting sheets
conveyed from an image forming apparatus, comprising: loading the
sheets conveyed from the image forming apparatus on a processing
tray; stapling a sheet bundle of the sheets loaded on the
processing tray by a stapler; and leading the stapled sheet bundles
to the sheet receiving tray and ejecting the same so as to shift
the stapling positions of the sheet bundles loaded on the sheet
receiving tray from each other at each upper and lower stages.
15. The sheet post-processing method according to claim 14 further
comprising: aligning the sheets loaded on the processing tray from
both sides in the conveying direction by a pair of aligning plates,
wherein the pair of aligning plates moves to a normal aligning
position and a position shifted from the normal aligning position
by a predetermined distance in a direction perpendicular to the
conveying direction; the stapler moves along edges in the conveying
direction of the sheets aligned and staples every conveyed sheet at
several places at the normal aligning position; and the sheet
bundles stapled are led onto the sheet receiving tray in the state
that they are shifted from each other in the direction
perpendicular to the conveying direction.
16. The sheet post-processing method according to claim 15, wherein
the pair of aligning plates are moved to the normal aligning
position and at a predetermined distance around the normal aligning
position in a first direction perpendicular to the conveying
direction and in a second direction opposite to the first
direction, and the sheet bundles stapled are moved onto the sheet
receiving tray in the state that they are alternately shifted in
the first direction and second direction.
17. The sheet post-processing method according to claim 15, wherein
when the pair of aligning plates are at the normal aligning
position, the stapler moves in the first direction and at a first
position and a second position in the movement direction, staples
sheets conveyed, and the stapler moves next in the opposite
direction of the first direction and at the second position and
first position in the movement direction, staples sheets conveyed
next.
18. The sheet post-processing method according to claim 15, wherein
assuming an interval between stapling positions by the stapler as
L1 and the predetermined distance of moving from the normal
aligning position as L2, L2<L1/2.
19. The sheet post-processing method according to claim 14, wherein
the stapler performs the stapling process for a first sheet bundle
loaded on the processing tray at a first stapling position and
performs the stapling process for a next second sheet bundle at a
second stapling position shifted from the first stapling position,
and the first sheet bundle and second sheet bundle stapled are
ejected onto the sheet receiving tray.
20. The sheet post-processing method according to claim 19, wherein
the first sheet bundle and second sheet bundle are stacked on the
sheet receiving tray in the state that both sides thereof in the
conveying direction are aligned.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No. 2005-368279
filed on Dec. 21, 2005, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a sheet post-processing
apparatus and a sheet post-processing method for post-processing
sheets ejected from an image forming apparatus such as a copier, a
printer, or a composite device.
[0004] 2. Description of the Related Art
[0005] In recent hears, in the image forming apparatus, to sort
sheets after image forming or to perform a post process of sheets
such as a stapling process, a sheet post-processing apparatus may
be installed in the neighborhood of a sheet ejection section of the
main body of the image forming apparatus. For example, the sheet
post-processing apparatus for performing the stapling process
aligns and staples a plurality of sheets (sheet bundles) by an
aligning means, ejects the stapled sheet bundles to a sheet
receiving tray, and stacks sequentially these sheet bundles on the
sheet receiving tray.
[0006] For example, in U.S. Pat. No. 5,263,697, a stapling
structure including a binding means for binding recording sheets
ejected from the image forming apparatus, a moving means for moving
the binding means along a plurality of binding positions of
recording sheets, and a position control means for controlling the
position of the moving means so as to make the final binding
position of the present recording sheets coincide with the starting
binding position of the next recording sheets is disclosed.
[0007] In the stapling structure disclosed in U.S. Pat. No.
5,263,697, the movement distance and movement time of the binding
means can be reduced, though stapled recording sheets, when
sequentially ejected, are ejected in the state that the binding
positions are overlaid each other, so that the recording sheets
bulge when stacked on the sheet receiving tray, thus it is
necessary to restrict the number of stacking sheets. Further, when
the succeeding sheet bundle stapled is ejected, a problem arises
that it presses out the sheet bundle erased already on the
tray.
[0008] There is a conventional sheet post-processing apparatus
available which can perform the stapling process. However, a
problem arises that when recording sheets are ejected and stacked
on the sheet receiving tray, the stapling positions are overlaid
each other, thus the number of stacking sheets is limited and by
the succeeding sheet bundle stapled, the sheet bundle on the sheet
receiving tray is pressed out and broken.
SUMMARY
[0009] An aspect of the present invention is to provide a sheet
post-processing apparatus and a sheet post-processing method for
reducing breaking of the stack when ejecting stapled sheets.
[0010] An embodiment of the present invention provides a sheet
post-processing apparatus for stapling and ejecting sheets conveyed
from an image forming apparatus, comprising a processing tray to
load the sheets conveyed from the image forming apparatus; stapling
means for stapling a sheet bundle of the sheets loaded on the
processing tray; and ejection means for leading the stapled sheet
bundle to a sheet receiving tray and ejecting the same so as to
shift the stapling positions of the plurality of sheet bundles
loaded on the sheet receiving tray from each other at each upper
and lower stages.
[0011] Furthermore, an embodiment of the present invention provides
a sheet post-processing method for stapling and ejecting sheets
conveyed from an image forming apparatus, comprising loading the
sheets conveyed from the image forming apparatus on a processing
tray; stapling a sheet bundle of the sheets loaded on the
processing tray by a stapler; and leading the stapled sheet bundles
to the sheet receiving tray and ejecting the same so as to shift
the stapling positions of the plurality of sheet bundles loaded on
the sheet receiving tray from each other at each upper and lower
stages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view showing the essential section
of the sheet post-processing apparatus relating to an embodiment of
the present invention;
[0013] FIG. 2 is a top view showing the essential section of the
sheet post-processing apparatus relating to the same
embodiment;
[0014] FIG. 3 is a schematic block diagram showing the sheet
post-processing apparatus relating to the same embodiment;
[0015] FIG. 4 is a perspective view showing the stapler of the
sheet post-processing apparatus relating to the same
embodiment;
[0016] FIG. 5 is a perspective view showing the longitudinal
aligning roller of the sheet post-processing apparatus relating to
the same embodiment;
[0017] FIG. 6 is an illustration showing the paddle of the sheet
post-processing apparatus relating to the same embodiment;
[0018] FIG. 7 is a schematic perspective view showing the queuing
tray and processing tray of the sheet post-processing apparatus
relating to the same embodiment;
[0019] FIG. 8 is a top view showing the queuing tray and processing
tray of the sheet post-processing apparatus relating to the same
embodiment;
[0020] FIG. 9 is a schematic perspective view showing the
transversal aligning plate and conveying belt of the sheet
post-processing apparatus relating to the same embodiment;
[0021] FIG. 10 is an illustration showing the state that the sheet
on the queuing tray or sheet receiving tray of the sheet
post-processing apparatus relating to the same embodiment is
pressed out;
[0022] FIG. 11 is an illustration showing the movement of the
queuing tray of the sheet post-processing apparatus relating to the
same embodiment is pressed out;
[0023] FIG. 12 is an illustration showing the operation after the
stapling process by a general sheet post-processing apparatus;
[0024] FIG. 13 is an operation illustration for explaining the
basic operation of the stapler of the sheet post-processing
apparatus of the present invention;
[0025] FIGS. 14A to 14D are operation illustrations for explaining
the stapling process and sheet ejection operation of the sheet
post-processing apparatus of the present invention;
[0026] FIGS. 15A to 15C are operation illustrations for explaining
the sheet ejection operation after the stapling process of the
sheet post-processing apparatus of the present invention;
[0027] FIG. 16 is an operation illustration showing a modification
in which the stapling positions of the sheet post-processing
apparatus of the present invention are shifted alternately; and
[0028] FIGS. 17A and 17B are operation illustrations showing a
modification in which the stapling positions of the sheet
post-processing apparatus of the present invention are set at one
position of the corner of each sheet bundle.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] Hereinafter, an embodiment of the present invention will be
explained in detail with reference to the accompanying drawings.
Further, in the drawings, to the same parts, the same numerals are
assigned and duplicated explanation will be omitted.
Embodiment 1
[0030] FIG. 1 is a perspective view showing the essential section
of the sheet post-processing apparatus relating to an embodiment of
the present invention, and FIG. 2 is a top view showing the
essential section of the sheet post-processing apparatus relating
to an embodiment of the present invention, and FIG. 3 is a drawing
for explaining the schematic constitution of the sheet
post-processing apparatus relating to an embodiment of the present
invention. Further, FIGS. 4 to 11 are drawings for explaining the
constitution of each unit of the sheet post-processing
apparatus.
[0031] The concrete constitution and operation of each unit shown
in FIGS. 1 and 2 will be made clear sequentially by the explanation
of the drawings shown in FIG. 4 and subsequent figures. Firstly,
the processing of sheets by the sheet post-processing apparatus of
the present invention will be explained mainly by referring to FIG.
3.
[0032] Paper P on which an image is formed by image forming
apparatus 5 such as a copier is ejected by a pair of exit rollers 6
and is conveyed by sheet post-processing apparatus 7. Sheet
post-processing apparatus 7, as shown in FIG. 3, includes queuing
tray 10, processing tray 12, stapler 14, first sheet receiving tray
16, second sheet receiving tray 18, fixed tray 19, and gate G.
[0033] Paper P ejected from pair of exit rollers 6 of image forming
apparatus 5 is received by a pair of entrance rollers 22 installed
in the neighborhood of the take-in port of sheet post-processing
apparatus 7. Entrance rollers 22 are composed of entrance upper
roller 22a and entrance lower roller 22b. Entrance rollers 22 are
driven by motor for driving the entrance rollers 26 (FIG. 1).
[0034] On the downstream side of entrance rollers 22, gate G for
branching sheets P received by entrance rollers 22 to two paths
(flow paths) is installed. Gate G has a sectional shape of a wedge
and the pointed part of the wedge is directed toward the
neighborhood of the rolling surfaces of entrance rollers 22. Gate G
is rotatably born by the side wall inside sheet post-processing
apparatus 7. The pointed part of the wedge takes the first position
pointing to entrance upper roller 22a of entrance rollers 22 and
the second position pointing to entrance lower roller 22b
thereof.
[0035] Namely, the first position is used to select the path when
the post process is required for sheet P and the second position is
used to select the path when the post process is not required for
sheet P.
[0036] When gate G is at the first position, sheet P is fed to
first sheet feed rollers 24 and is sent from first sheet feed
rollers 24 to queuing tray 10. Between entrance rollers 22 and
queuing tray 10, sheet path guide 36 (FIG. 1) for leading sheet P
to first sheet feed rollers 24 is installed. First sheet feed
rollers 24 are composed of an upper sheet feed roller and a lower
sheet feed roller.
[0037] On the downstream side of queuing tray 10, processing tray
12 for stacking sheets P dropped and fed from queuing tray 10 is
arranged. Processing tray 12, while sheets P are stapled by stapler
14 which is a processing mechanism for performing the post process,
aligns and supports sheets P stacked.
[0038] When sheets of a predetermined number are accumulated on
queuing tray 10, as shown in FIG. 7, tray members 10a and 10b are
opened in the directions of arrows n and m by queuing tray motor 34
(FIG. 1) and sheets P are dropped onto processing tray 12 by the
own weight and are fed to stapler 14.
[0039] Stapler 14, as shown in FIG. 4, is slidden and positioned by
stapler driver 49 in direction u and performs the stapling process.
Further, stapler 14 is composed of one unit and in FIG. 4, the
conditions before and after sliding is shown. Processing tray 12,
to align a plurality of sheets P dropped and fed from queuing tray
10 in the longitudinal direction which is the conveying direction,
has a pair of upper longitudinal aligning roller 38a and lower
longitudinal aligning roller 38b shown in FIGS. 5 and 6.
[0040] Upper and lower longitudinal aligning rollers 38a and 38b
serve as bundle conveying rollers for grasping sheet bundle T after
ending of the stapling process and taking out it from stapler 14.
Upper longitudinal aligning roller 38a is driven by motor for
driving the upper longitudinal aligning roller 40 and lower
longitudinal aligning roller 38b is driven by motor for driving the
lower longitudinal aligning roller 42.
[0041] Further, when sheet P is dropped and fed to processing tray
12, at the position where the rear end of sheet P is dropped,
paddle 44 rotatable for aligning sheet P at the uppermost position
loaded on processing tray 12 in the longitudinal direction is
arranged.
[0042] Paddle 44, as shown in FIG. 6, includes receiving portion
44a of sheets P dropped and fed to processing tray 12, slapping
portion 44b for slapping sheets P onto processing tray 12, and
sending portion 44c for aligning sheets P on processing tray 12 and
is driven by paddle motor 46. Paddle 44 is made of a rubber
material, thereby is elastic.
[0043] At the end of processing tray 12 on the side of stapler 14,
stopper 45 for making contact with the rear end of sheet P and
restricting the rear end position is installed. Almost at the
center of processing tray 12, conveying belt 50 for conveying sheet
bundle T which is stapled and is taken out from stapler 14 by upper
and lower longitudinal aligning rollers 38a and 38b up to first
sheet receiving tray 16 or second sheet receiving tray 18 is
installed. To conveying belt 50, hook 50a for hooking the rear end
of sheet bundle T is attached.
[0044] Queuing tray 10 can drop and feed sheets P to processing
tray 12, though it can be used to convey sheets P toward first
sheet receiving tray 16 or second sheet receiving tray 18, and the
conveyance of sheets P toward sheet receiving trays 16 and 18 is
executed by bringing queuing tray roller 28 into contact with
sheets P on queuing tray 10. Queuing tray roller 28 is controlled
in the vertical movement by source for driving the queuing tray
roller 30 and is driven to rotate by motor for driving the queuing
tray roller (FIG. 2).
[0045] As shown in FIG. 3, queuing tray 10, to support sheets P so
as to position the front end of each of sheets P higher than the
rear end thereof, is arranged at an inclination angle of .theta.1.
First sheet receiving tray 16 and second sheet receiving tray 18
are moved upward by receiving tray driver 52 and either of them is
selected. First sheet receiving tray 16 or second sheet receiving
tray 18 is moved upward or downward to an almost same height as
that of queuing tray 10 or processing tray 12 when stacking sheets
P to improve the alignment of sheets P to be ejected. Further,
first sheet receiving tray 16 or second sheet receiving tray 18, to
support sheets P so as to position the front end of each of sheets
P higher than the rear end thereof, is arranged at an inclination
angle of .theta.2.
[0046] As shown in FIGS. 7 and 8, queuing tray 10 has a pair of
tray members 10a and 10b formed so that the wall surface thereof is
projected, receives sheets P in the state that it slides in the
width direction of sheets P, and supports both sides of sheets P.
On tray members 10a and 10b , queuing stoppers 10c and 10d for
controlling the rear ends of sheets P are installed.
[0047] Queuing tray 10 is slidden and moved by queuing tray motor
34 (FIG. 2). Between queuing tray 10 and processing tray 12, when
dropping and feeding sheets P on queuing tray 10 to processing tray
12, to prevent sheets P from deviating from the conveying direction
to the transverse direction perpendicular thereto and align sheets
P in the transverse direction, as shown in FIG. 9, transversal
aligning plates 47a and 47b are installed. Transversal aligning
plates 47a and 47b can slide in direction v so as to fit to the
width of sheets P by motor for moving the transversal aligning
plate 48, thereby can change the aligning position.
[0048] As shown in FIG. 3, when gate G is at the second position,
sheets P requiring no post process are fed to second sheet feed
rollers 60 and furthermore, are fed to third sheet feed rollers 61.
Second sheet feed rollers 60 and third sheet feed rollers 61 are
respectively composed of an upper sheet feed roller and a lower
sheet feed roller. Papers P conveyed from third sheet feed roller
61 are sent to fixed tray 19 installed on the top of sheet
post-processing apparatus 7.
[0049] Further, by motors 26, 34, 40, 42, 46, and 48 for driving
the various mechanisms aforementioned and drivers 49 and 52 are
driven and controlled by a control circuit (not drawn).
[0050] Next, the operation of sheet post-processing apparatus 7
will be explained in accordance with the flow of sheets. When
sheets P with an image formed by image forming apparatus 5 are fed
from exit rollers 6, sheet post-processing apparatus 7, depending
on (1) a case that sheets P are not post-processed, (2) a case that
sheets P are post-processed and preceding sheet P finishes the post
processing, and (3) a case that sheets P are post-processed and
preceding sheet P is in execution of the post processing, performed
different operations.
[0051] Firstly, in (1) the case of no execution of the post
processing, the pointed part of the wedge of gate G is almost at
the second position pointing to entrance lower roller 22b. Papers P
fed from entrance rollers 22 are fed to second sheet feed rollers
60 and furthermore are fed to third sheet feed rollers 61. Papers P
fed from the third sheet feed rollers are ejected to fixed tray 19
on the top.
[0052] Next, (2) the case that the post process (the stapling
process) is performed and there are no preceding sheets P on
processing tray 12 will be described. At this time, queuing tray 10
slides and moves tray members 10a and 10b respectively up to the
positions indicated by the dotted lines shown in FIG. 11 in the
directions of arrows m and n to open the drop and feed path of
sheets P. Further, transversal aligning plates 47a and 47b, to
align sheets P dropped from sheet feed rollers 24 in the transverse
direction, are arranged so as to make the interval between
transversal aligning plates 47a and 47b almost equal to the width
of sheets P. By doing this, sheets P fed by sheet feed rollers 24
are dropped and fed directly to processing tray 12 without
interrupting the conveyance by queuing tray 10.
[0053] At time of drop and feed, upper longitudinal aligning roller
38a is shifted upward and receiving portion 44a of paddle 44
receives the rear ends of sheets P. Both sides of sheets P are
dropped by keeping contact with transversal aligning plates 47a and
47b so as to align sheets P in the transverse direction. Next,
paddle 44 rotates in the direction of arrow o shown in FIG. 6, and
the rear ends of sheets P are dropped from receiving portion 44a,
and sheets P are slapped down on processing tray 12 by slapping
portion 44b.
[0054] Furthermore, paddle 44 sends sheets P in the direction of
arrow q by sending portion 44c, and the rear ends of sheets P make
contact with stopper 45, and the alignment of sheets P in the
longitudinal direction is completed. Further, the alignment of
sheets P in the longitudinal direction on processing tray 12 may be
executed by upper longitudinal aligning plate 38a by moving it up
and down each time.
[0055] By aligning sequentially sheets P with an image formed in
the transverse direction and longitudinal direction in this way,
sheets P are stacked from sheet feed rollers 24 directly on
processing tray 12. When sheets P reach a predetermined number,
stapler 14 staples sheets P on processing tray 12 at a desired
position in a bundle shape and forms sheet bundle T. Hereafter, as
shown in FIG. 6, upper longitudinal aligning roller 38a rotating in
the direction of arrow r and lower longitudinal aligning roller 38b
rotating in the direction of arrow s grasp sheet bundle T and
convey it toward first sheet receiving tray 16.
[0056] The rear end of sheet bundle T, when passing through upper
and lower longitudinal aligning rollers 38a and 38b, is hooked by
hook 50a of conveying belt 50 rotating in the direction of arrow t
shown in FIG. 5 and is sent onto first sheet receiving tray 16.
[0057] Further, first sheet receiving tray 16 is arranged at an
inclination angle of .theta.2 and the front end of each sheet is
positioned higher than the rear end thereof, so that preceding
sheet bundle T ejected on first sheet receiving tray 16 will not be
pressed out by making contact with the front end of succeeding
sheet bundle T. Further, even if preceding sheet bundle T is
slightly shifted by succeeding sheets P, first sheet receiving tray
has an inclination angle of .theta.2, so that sheet bundle T drops
by its own weight and the stapling process of sheets P aligned and
stacked in the state that the rear ends are aligned on first sheet
receiving tray 16 is completed.
[0058] In this way, sheets are sequentially stacked on first sheet
receiving tray 16. Further, first sheet receiving tray 16 is
arranged at an inclination angle of .theta.2 and the front end of
each sheet is positioned higher than the rear end thereof, so that
for example, even if sheets P are ejected onto first sheet
receiving tray 16 in the state that they are curled convexly,
preceding sheets loaded on first sheet receiving tray 16 will not
be pressed out by making contact with the front ends of succeeding
sheets P. Namely, ejected sheets P are sequentially loaded on first
sheet receiving tray 16 without disturbing the order.
[0059] Next, (3) the case that the stapling process is performed
and preceding sheets P in execution of the stapling process remain
on processing tray 12 will be described. At this time, queuing tray
10 slides and moves tray members 10a and 10b respectively from the
positions indicated by the dotted lines shown in FIG. 11 in the
opposite direction of the direction of arrow m and the opposite
direction of the direction of arrow n and can support sheets P at
the positions indicated by the solid lines shown in FIG. 11.
Further, queuing tray roller 28 is shifted above queuing tray 10 so
as to prevent sheets P from disturbance. Papers P ejected from
image forming apparatus 5 and fed by sheet feed rollers 24 are
loaded once on queuing tray 10 to wait for processing tray 12 to
become empty.
[0060] Papers P loaded on queuing tray 10 are sent toward queuing
stoppers 10c and 10d by queuing tray roller 28 which drops down
onto queuing tray 10 and rotates in the opposite direction of the
direction of arrow f shown in FIG. 3 and are longitudinally aligned
by making the rear ends of sheets P touch queuing stoppers 10c and
10d. Furthermore, queuing tray 10 is arranged at an inclination
angle of .theta.1 and the front end of each sheet is positioned
higher than the rear end thereof, so that sheets P are aligned
longitudinally by making the rear ends touch queuing stoppers 10c
and 10d by the own weight.
[0061] Fed sheets P are sequentially loaded on queuing tray 10
without disturbing the order. Further, even if preceding sheets P
are pressed and slightly shifted by succeeding sheets P, queuing
tray 10 has an inclination angle of .theta.1, so that sheets P drop
by the own weight down to the position where the rear ends make
contact with queuing stoppers 10c and 10d and are aligned and
stacked in the state that the rear ends are aligned on queuing tray
10.
[0062] During this period, when preceding sheets P on processing
tray 12 are ejected on the side of first sheet receiving tray 16
and processing tray 12 becomes empty, queuing tray 10 slides and
moves tray members 10a and 10b 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
respectively in the directions of arrows m and n.
[0063] By doing this, for example, two sheets P waiting on queuing
tray 10, when tray members 10a and 10b reach the positions
indicated by the alternate long and short dash lines shown in FIG.
11, are dropped and fed onto processing tray 12 from the interval
between tray members 10a and 10b. At this time, transversal
aligning plates 47a and 47b are arranged so that the interval
therebetween becomes almost equal to the width of sheets P.
Therefore, sheets P dropped from queuing tray 10 are controlled on
both sides by transversal aligning plates 47a and 47b and are
aligned in the transverse direction.
[0064] Lower side sheet P of two sheets P dropped from processing
tray 12 is sent in the direction of arrow q by lower longitudinal
aligning roller 38b rotating in the opposite direction of the
direction of arrow s shown in FIG. 6, and the rear end of sheet P
makes contact with stopper 45, thus the alignment of sheets P in
the longitudinal direction is completed. Upper side sheet P of two
sheets P dropped from processing tray 12 is sent in the direction
of arrow q by upper longitudinal aligning roller 38a rotating in
the opposite direction of the direction of arrow r, and the rear
end of sheet P makes contact with stopper 45, thus the alignment of
sheets P in the longitudinal direction is completed, and hereafter,
upper longitudinal aligning roller 38a is shifted upward.
[0065] Third and subsequent sheets P ejected from image forming
apparatus 5 are dropped and fed directly to processing tray 12 from
the interval between tray members 10a and 10b without waiting on
queuing tray 10. Third and subsequent sheets P are sequentially
aligned on sheets P which are previously loaded on processing tray
12 by paddle 44.
[0066] When sheets P loaded on processing tray 12 reach a
predetermined number, sheets P are stapled by stapler 14 and sheet
bundle T is formed. Hereafter, sheet bundle T is conveyed toward
first sheet receiving tray 16 by upper and lower longitudinal
aligning rollers 38a and 38b, and furthermore the rear end thereof
is hooked by hook 50a of conveying belt 50, and sheet bundle T is
ejected onto first sheet receiving tray 16, and the stapling
process of sheets P is completed.
[0067] The aforementioned is the explanation of the whole operation
of sheet post-processing apparatus 7. Next, the constitution of the
stapler and transversal aligner which are characteristic units of
the present invention will be explained.
[0068] Generally, the stapling process includes binding of one
corner of each sheet and binding of several places (for example,
two places) along one edge of each sheet. Particularly in the case
of binding several places, when a sheet bundle stapled is ejected,
as shown in FIG. 12, sheet bundles T are stacked on sheet receiving
tray 16, and stapling positions ST are overlaid each other and
bulge, so that when succeeding sheet bundle T is ejected, sheet
bundles T already ejected on tray 16 are pressed out and may be
broken.
[0069] The sheet post-processing apparatus of the present invention
is characteristic in that such bulging due to overlaid stapling
positions is reduced and sheet bundles are prevented from breaking
of the stack.
[0070] FIG. 13 is a drawing for explaining the operation of stapler
14. Stapler 14, as shown in FIG. 4, can slide in direction u by
stapler driver 49 and when binding the corners of sheets P, it
moves to the position indicated by the solid line or alternate long
and short dash line shown in FIG. 13 and then performs the stapling
process. Further, when binding several places (for example, two
places) along the edges of sheets P, stapler 14 moves to the
positions indicated by the dotted lines shown in FIG. 13 and
performs stapling process ST.
[0071] FIGS. 14A to 14D are drawings for explaining the stapling
method of the present invention, show the case of binding two
places along the edge of sheet P, and explain the movement of
stapler 14 and transversal aligning plates 47a and 47b.
[0072] FIG. 14A shows the state that sheet P is aligned at the
normal aligning position by transversal aligning plates 47a and
47b. Transversal aligning plates 47a and 47b can move in the first
direction (direction A1) perpendicular to the sheet conveying
direction and the opposite direction (direction A2) of the first
direction. In transversal aligning plate 47a, position b1 is a
specified position and in transversal aligning plate 47b, position
b2 is a specified position. When the transversal aligning plates
are at the normal aligning positions, transversal aligning plates
47a and 47b move from positions b1 and b2 to positions c1 and c2
and sheets P are aligned in the width direction from both sides in
the conveying direction.
[0073] On the other hand, stapler 14 is slidden in direction A1
along the edge of sheet P by stapler driver 49, is stopped at first
stapling position al, and performs the stapling process. Next,
stapler 14 is slidden in direction A1 by distance L1 along the edge
of sheet P, is stopped at second stapling position a2, and performs
the stapling process. In this way, stapler 14 is stopped at several
places in the movement process and performs the stapling
process.
[0074] When the stapling process at the first and second stapling
positions is finished, as shown in FIG. 14B, transversal aligning
plates 47a and 47b move in direction A2 at predetermined distance
L2, and transversal aligning plate 47a moves to position b1, and
transversal aligning plate 47b moves to specified position d2. By
doing this, first sheet bundle T stapled is conveyed to the
position shifted in direction A2 by distance L2 from the normal
aligning position, and is conveyed to sheet receiving tray 16 (or
18) by conveying belt 50. Further, interval L1 between first
stapling position a1 and second stapling position a2 is about 120
mm and ST indicates the stapled state.
[0075] When first sheet bundle T stapled in this way is ejected,
transversal aligning plates 47a and 47b, as shown in FIG. 14C, move
again to normal aligning positions c1 and c2, and sheets P conveyed
next are aligned in the width direction by transversal aligning
plates 47a and 47b after movement and aligned at this aligning
position.
[0076] Stapler 14 is at previous second stapling position a2 and
performs the stapling process at stapling position a2. Next,
stapler 14 moves in direction A2 along the edge of sheet P by
distance L1, is stopped at first stapling position a1, and performs
the stapling process. In this way, stapler 14 stops at several
places in the movement process in the opposite direction and
performs the stapling process.
[0077] When the stapling process is finished in this way, as shown
in FIG. 14D, transversal aligning plates 47a and 47b move in
direction A1 at predetermined distance L2, and transversal aligning
plate 47a moves to specified position e1, and transversal aligning
plate 47b moves to position b2. By doing this, second sheet bundle
T stapled is conveyed to the position shifted in direction A1 by
distance L2 from the normal aligning position, and is conveyed to
sheet receiving tray 16 (or 18) by conveying belt 50. And, the
operations shown in FIGS. 14A to 14D are repeated and the stapling
process is performed sequentially.
[0078] In the aforementioned movement of stapler 14, distance L1
between the first stapling position and the second stapling
position depends on the binding intervals of sheets, while movement
distance L2 of transversal aligning plates 47a and 47b in the
separation direction from the normal aligning position may be a
distance that stapling positions ST of the first sheet bundle and
second sheet bundle which are stapled are not overlaid each other,
for example, a distance that the stapling positions are shifted by
about 15 mm. When movement distance L2 is set, for example, to less
than L1/2, the movement distance of transversal aligning plates 47a
and 47b can be made smaller.
[0079] As mentioned above, stapler 14, at the normal aligning
position, can perform the stapling process during the alternating
motion from position al to a2 and from position a2 to a1, thus the
movement distance of stapler 14 can be minimized. Therefore, the
time in correspondence with the movement of stapler 14 can be
reduced and the process can be performed at high speed. Further,
after the stapling process, transversal aligning plates 47a and 47b
convey sheet bundles alternately in directions A1 and A2.
[0080] Further, in the examples shown in FIG. 14, the positions of
transversal aligning plates 47a and 47b can be moved in directions
A1 and A2 around the normal aligning positions, though the
positions may be moved in either of directions A1 and A2.
[0081] Namely, the sheet bundle stapled in FIG. 14A is conveyed
straight, and the sheet bundle conveyed next is stapled at the
normal aligning position, and then transversal aligning plates 47a
and 47b are moved in either of directions A1 and A2, and the
concerned sheet bundle is shifted and conveyed from the sheet
bundle conveyed previously. In this case, it is necessary to make
the movement distance in one direction longer than distance L2,
though the stapling positions of conveyed sheet bundles can be
shifted from each other.
[0082] Further, in the example shown in FIG. 14, the first sheet
bundle T subjected to a staple process is conveyed to the position
shifted by the distance L2 in the direction A2 from the normal
aligning position and conveyed to the sheet receiving tray 16 (or
18) by the conveying belt 50, and the next second sheet bundle T
subjected to a staple process is conveyed to the position shifted
by the distance L2 in the direction A1 from the normal aligning
position and conveyed to the sheet receiving tray 16 (or 18) by the
conveying belt 50. In other words, after the stapling process, the
sheet bundles are shifted right and left and are conveyed to the
sheet receiving tray. Alternatively, however, the sheet bundles may
be shifted to the right and left, then stapled, and conveyed
straight to the sheet receiving tray. That is, in the state shown
in FIG. 14A, the first sheet bundle T is only aligned but not
stapled and is shifted to the position shown in FIG. 14B in the
direction A2. The first sheet bundle T so shifted is stapled, and
then is conveyed onto the sheet receiving tray. Next, in the state
shown in FIG. 14C, the second sheet bundle T is only aligned but
not stapled and is shifted to the position shown in FIG. 14D in the
direction A1. The second sheet bundle T shifted is stapled, and
then is conveyed onto the sheet receiving tray.
[0083] FIGS. 15A to 15C show the situation that sheet bundles T
stapled are sequentially ejected to sheet receiving tray 16, and
FIG. 15A shows that stapling positions ST of sheet bundles T are
shifted from each other at the upper and lower stages, and FIG. 15B
shows the overlaying condition of stapling positions ST of sheet
bundles T. As shown in FIG. 15B, the stapling positions are shifted
from each other, thus height HI of the overlaid portion is lowered.
Therefore, even if sheet bundles T are stacked on sheet receiving
tray 16, the bulge can be lowered. Further, even if succeeding
sheet bundle T is ejected, the phenomenon that sheet bundle T
already ejected on tray 16 is pressed out can be reduced.
[0084] FIG. 15C shows the overlaying condition of sheet bundles T
by the conventional stapling process for reference. In this case,
the stapling positions are all the same position, so that height H2
of the overlaid portion is raised (H2>H1), thus the sheet
bundles are broken.
[0085] As mentioned above, in the embodiment of the present
invention, sheets stapled and ejected, when stacked on sheet
receiving tray 16 (or 18), can be prevented from breaking and
pressing out. Therefore, a sheet post-processing apparatus
convenient to a user can be obtained free of a lowering of the
efficiency of the image forming apparatus.
[0086] In the embodiment aforementioned, the stapling positions of
every sheet bundle are the same positions, and the sheet bundles
are shifted from each other after the stapling process and are
ejected to sheet receiving tray 16 (or 18). However, the present
invention is not limited to it.
[0087] As shown in FIG. 16, it is possible to shift alternately the
stapling positions of sheet bundles T, staple them, and then eject
them to sheet receiving tray 16 (or 18). Namely, first sheet bundle
T1 is stapled at first stapling positions A1 and B1, and next
second sheet bundle T2 is stapled at second stapling positions A2
and B2 shifted from first stapling positions A1 and B1, and next
third sheet bundle T3 is stapled at first stapling positions A1 and
B1 similarly to first sheet bundle T1, and next fourth sheet bundle
T4 is stapled at second stapling positions A2 and B2 similarly to
second sheet bundle T2. When sheet bundles T1, T2, T3, and T4
stapled in this way are ejected to sheet receiving tray 16 (or 18),
as a result, as shown in FIG. 16, the sheet bundles are stacked on
sheet receiving tray 16 (or 18) in the state that the stapling
positions are shifted alternately. In this case, sheet bundles T1,
T2, T3, and T4 are stacked on sheet receiving tray 16 (or 18) in
the state that both sides thereof in the conveying direction are
aligned.
[0088] Furthermore, as shown in FIG. 17A, when the stapling
positions of sheet bundles T are set to one same place of the
corners of sheet bundles T, similarly to FIG. 15B, after the
stapling process, it is possible to shift alternately sheet bundles
T and eject them to sheet receiving tray 16 (or 18).
[0089] Further, as shown in FIG. 17B, even when the stapling
positions of sheet bundles T are set to one place of the corners of
sheet bundles T, it is possible to shift alternately the stapling
positions at one place of the corners of sheet bundles T, staple
them, and then eject them to sheet receiving tray 16 (or 18).
Namely, first sheet bundle T11 is stapled at first stapling
position C1 of the corner thereof, and next second sheet bundle T12
is stapled at second stapling position C2 shifted from first
stapling position C1, and next third sheet bundle T13 is stapled at
first stapling position C1 similarly to first sheet bundle T11, and
next fourth sheet bundle T14 is stapled at second stapling position
C2 similarly to second sheet bundle T12. When sheet bundles T11,
T12, T13, and T14 stapled in this way are ejected to sheet
receiving tray 16 (or 18), as a result, as shown in FIG. 17B, the
sheet bundles are stacked on sheet receiving tray 16 (or 18) in the
state that the stapling positions are shifted alternately. In this
case, sheet bundles T11, T12, T13, and T14 are stacked on sheet
receiving tray 16 (or 18) in the state that both sides thereof in
the conveying direction are aligned.
[0090] Further, the present invention is not limited to the above
explanation and without being deviated from the claims, the present
invention can be modified variously. For example, the examples that
stapler 14 performs the stapling process at one place and two
places are explained, though it can perform the stapling process at
three places.
* * * * *