U.S. patent application number 13/216450 was filed with the patent office on 2012-02-02 for sheet post-processing apparatus.
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 | 20120025452 13/216450 |
Document ID | / |
Family ID | 38193936 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120025452 |
Kind Code |
A1 |
Terao; Yasunobu ; et
al. |
February 2, 2012 |
SHEET POST-PROCESSING APPARATUS
Abstract
The disclosure concerns a standby tray for making a sheet at the
position above a processing tray. The sheet on the standby tray is
dropped and supplied onto the processing tray. The upper end of the
center area of a shutter supporting the rear end of the sheet on a
sheet discharge tray which is slidable to the sheet discharge
section of the standby tray or processing tray is made lower than
the upper end of the peripheral area of the shutter. Movable
portions of the shutter are extended when the sheet discharge tray
is slid to close the sheet discharge sections of the processing
tray and/or standby tray.
Inventors: |
Terao; Yasunobu;
(Izunokuni-shi, JP) ; Yamamoto; Mikio;
(Izunokuni-shi, JP) ; Sugizaki; Yoshiaki;
(Sunto-gun, JP) ; Taki; Hiroyuki; (Izunokuni-shi,
JP) |
Assignee: |
TOSHIBA TEC KABUSHIKI
KAISHA
Tokyo
JP
|
Family ID: |
38193936 |
Appl. No.: |
13/216450 |
Filed: |
August 24, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11616076 |
Dec 26, 2006 |
8023880 |
|
|
13216450 |
|
|
|
|
Current U.S.
Class: |
271/207 |
Current CPC
Class: |
G03G 15/6552 20130101;
G03G 21/1638 20130101; G03G 2221/1675 20130101 |
Class at
Publication: |
271/207 |
International
Class: |
B65H 31/24 20060101
B65H031/24; B65H 31/34 20060101 B65H031/34 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2005 |
JP |
2005-372752 |
Claims
1. (canceled)
2. A sheet post-processing apparatus comprising: a processing tray
to support a sheet discharged from an image forming apparatus; a
processing mechanism to perform post-processing for the sheet; a
sheet discharge tray to load the sheet, the sheet discharge tray
tilted such that the discharge direction front end of the sheet is
positioned higher than the discharge direction rear end thereof; a
discharge mechanism to discharge the sheet from the processing tray
to the sheet discharge tray; and a rear end supporting mechanism
which height of an upper end of a center area of the rear end
supporting mechanism is lower than an upper end of peripheral area
of the rear end supporting mechanism and which slides in a vertical
direction at the discharge direction rear end of the sheet on the
sheet discharge tray.
3. The apparatus according to claim 2, wherein the sheet discharge
tray moves to the vertical direction and the rear end supporting
mechanism slides along with the move of the sheet discharge
tray.
4. The apparatus according to claim 3, wherein the rear end
supporting mechanism closes a sheet discharge section of the sheet
discharge tray if the sheet discharge tray moves to the vertical
direction.
5. The apparatus according to claim 2, wherein the sheet discharge
tray includes an upper sheet discharge tray and a lower sheet
discharge tray.
6. The apparatus according to claim 2, further comprising a standby
tray which is arranged over the processing tray to stand by the
sheet discharge from an image forming apparatus.
7. The apparatus according to claim 6, wherein the sheet discharge
tray moves to the vertical direction until to a sheet discharge
section if the sheet is discharged from the standby tray to the
sheet discharge tray, and the rear end supporting mechanism slides
along with the move of the sheet discharge tray to closes a sheet
discharge section of the sheet discharge tray.
8. The apparatus according to claim 6, wherein the standby tray
includes a pair of trays to support the both sides of the sheet,
and the stand by tray drop and supply the sheet onto the processing
tray between the pair of trays.
9. The apparatus according to claim 2, further comprising a center
alignment roller which is arranged at one end of the processing
tray on the sheet discharge tray side and rotates in the forward
direction or reverse direction and a slide alignment roller which
shaft is same of the center alignment roller, and which are
arranged on both sides of the center alignment roller, and rotate
in the forward direction or reverse direction.
10. The apparatus according to claim 9, wherein the center area of
the rear end supporting mechanism is an area that faces to the
center alignment roller.
11. The apparatus according to claim 9, wherein the discharge
mechanism is a carrier belt and the center alignment roller is a
pair of center alignment rollers which are disposed symmetrically
with respect to the conveyor belt.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of application Ser. No.
11/616,076 filed on Dec. 26, 2006, the entire contents of which are
incorporated herein by reference.
[0002] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2005-372752
filed on Dec. 26, 2005, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a sheet post-processing
apparatus that performs post-processing for a sheet on which an
image has been formed in an image forming apparatus such as a
copier, a printer, or a composite device.
[0005] 2. Description of the Related Art
[0006] In recent years, there is developed a sheet post-processing
apparatus, which is disposed adjacent to the sheet discharge
section of an image forming apparatus main body for the purpose of
performing post-processing for a sheet on which an image has been
formed in the image forming apparatus. The sheet post-processing
apparatus performs post-processing for a sheet, such as sorting of
printed sheets discharged from the image forming apparatus or
stapling thereof. The sheet post-processing apparatus performs
post-processing for a succeeding sheet after completion of the
post-processing for a preceding sheet. In order for the sheet
post-processing apparatus to wait until the post-processing for a
preceding sheet has been completed, an apparatus in which a
retreating path is formed in the middle of a path reaching to a
stapler is disclosed in Japanese Patent Publication (Kokoku) No.
H6-99070.
[0007] However, in the case where the retreating path is formed in
the middle of a path reaching to a stapler as described above, the
length of a sheet path extending from the discharge section of the
image forming apparatus main body to the stapler is increased. This
may prevent size reduction of the entire apparatus.
[0008] In light of the above, an apparatus in which a processing
tray for use in staple processing and a standby tray which retains
a sheet to be supplied to the processing tray in a standby mode are
vertically provided to reduce the length of the sheet path has been
proposed. In this apparatus, a sheet is dropped from the standby
tray and is supplied onto the processing tray. Further, such an
apparatus has a sheet discharge tray on which a sheet discharged
from the standby tray or processing tray is placed and a rear end
guide that supports the rear end of the sheet on the discharge tray
between the discharge tray.
[0009] However, if deformation of a sheet occurs when the sheet is
discharged from the standby tray or processing tray to the sheet
discharge tray, the sheet is caught by the rear side which may
result in sheet jamming. Further, if the rear guide contacts a
sheet when the sheet is aligned on the processing tray, the rear
guide serves as resistance to adversely affecting the sheet
alignment performance.
[0010] Further, in some cases, the sheet discharge tray is slid on
the side surface of the post-processing apparatus main body, with
the sheet placed thereon, so as to be disposed adjacent to the
position of the standby tray or processing tray. If the rear end of
the sheet on the discharge tray is slipped from the upper end of
the rear guide at this time, the sheet may be fed back to the
processing tray or standby tray side.
[0011] To cope with the above problems, a small-sized sheet
post-processing apparatus that prevents sheet jamming from
occurring when the sheet is discharged from the standby tray or
processing tray to the discharge tray without adversely affecting
the sheet alignment performance made in the processing tray has
been desired. Further, a sheet post-processing apparatus that
prevents the sheet placed on the discharge tray from being fed back
to the backside at the time of the slide of the discharge tray has
been desired.
SUMMARY OF THE INVENTION
[0012] An aspect of the present invention is to provide a sheet
post-processing apparatus in which a sheet is dropped from the
standby tray to thereby be supplied to the processing tray and the
length of a sheet path is reduced. It is desirable for the sheet
post-processing apparatus to prevent sheet jamming from occurring
when the sheet is discharged to the discharge tray, to exhibit an
excellent sheet alignment performance on the processing tray, and
to prevent the sheet placed on the discharge tray from reversely
being fed to the processing tray side at the time of the slide of
the discharge tray.
[0013] According to an embodiment of the present invention, a sheet
post-processing apparatus is characterized by containing: a standby
tray for making a sheet discharged from an image forming apparatus
stand by, a processing tray arranged under the standby tray, a
processing mechanism for performing post-processing for the sheet,
a sheet discharge tray for loading the sheet, the sheet discharge
tray being slidably arranged adjacent to the standby tray or the
processing tray on the downstream side with respect to the standby
tray and processing tray in the sheet discharge direction and
tilted such that the discharge direction front end of the sheet is
positioned higher than the discharge direction rear end thereof,
and a rear end supporting mechanism arranged on the discharge
direction rear end side and allows the rear end of the sheet on the
sheet discharge tray to be brought into contact therewith, wherein
the center area upper end of the rear end supporting mechanism is
positioned lower than the peripheral area upper end of the rear end
supporting mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view showing the main part of a
sheet post-processing apparatus according to an embodiment of the
present invention;
[0015] FIG. 2 is a top view of the main part of the sheet
post-processing apparatus according to the embodiment of the
present invention;
[0016] FIG. 3A is a view schematically showing a configuration of
the sheet post-processing apparatus according to the embodiment of
the present invention in a state where a sheet is discharged onto a
first sheet discharge tray;
[0017] FIG. 3B is a view schematically showing a configuration of
the sheet post-processing apparatus according to the embodiment of
the present invention in a state where the sheet discharge tray is
slid;
[0018] FIG. 4 is a perspective view showing a stapler of the sheet
post-processing apparatus according to the embodiment of the
present invention;
[0019] FIG. 5 is an explanatory view showing vertical alignment
rollers according to the embodiment of the present invention;
[0020] FIG. 6 is a perspective view showing a paddle mechanism
according to the embodiment of the present invention;
[0021] FIG. 7 is a perspective view schematically showing a standby
tray and a processing tray according to the embodiment of the
present invention;
[0022] FIG. 8 is a top view of the standby tray and processing tray
according to the embodiment of the present invention;
[0023] FIG. 9 is a perspective view schematically showing
horizontal alignment plates and a conveyer belt according to the
embodiment of the present invention;
[0024] FIG. 10 is a perspective view schematically showing a part
of a shutter according to the embodiment of the present invention
in a state where a sheet is discharged onto the first sheet
discharge tray;
[0025] FIG. 11 is a perspective view schematically showing a part
of the shutter according to the embodiment of the present invention
in a state where the sheet discharge tray is slid; and
[0026] FIG. 12 is an explanatory view showing the movement of the
standby tray according to the embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Hereinafter, an embodiment of the present invention will be
described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view showing the main part of a sheet
post-processing apparatus 7 according to an embodiment of the
present invention. FIG. 2 is a top view of the main part of the
sheet post-processing apparatus 7. FIGS. 3A and 3B are views each
schematically showing a configuration of the sheet post-processing
apparatus 7 disposed adjacent to an image forming apparatus 5 such
as a copier.
[0028] The sheet post-processing apparatus 7 has a pair of entrance
rollers 22 have an upper roller 22a and lower roller 22b that feed
a sheet P, on which an image has been formed by the image forming
apparatus 5 and which is discharged by a pair of discharge rollers
6, into the sheet post-processing apparatus 7. The entrance rollers
22 are driven by an entrance roller motor 26. Between the entrance
rollers 22 and a standby tray 10, a sheet path ceiling 36 for
leading the sheet P to a pair of sheet feed rollers 24 is
installed. Under the standby tray 10, a processing tray 12 for
loading the sheets P dropped and supplied from the standby tray 10
is arranged.
[0029] While the sheets P are stapled by a stapler 14 which is a
processing mechanism for performing post-processing, the processing
tray 12, supports the sheets P to be loaded in an aligned state. As
shown in FIG. 4, the stapler 14 is slidable by a staple drive
section 49 in u direction denoted by the arrow in the illustration.
The stapler 14 performs staple processing after being rotated in
accordance with the staple direction and positioned. The processing
tray 12 has a pair of upper vertical alignment roller 38a and lower
vertical alignment roller 38b shown in FIG. 5 at the rear end side
portion of the sheet P.
[0030] The upper vertical alignment roller 38a and lower vertical
alignment roller 38b align a plurality of sheets P dropped and
supplied from the standby tray 10 in the vertical direction which
is a feeding direction. The upper and lower vertical alignment
rollers 38a and 38b serve as bundle feeding rollers for holding a
sheet bundle T after stapled and taking out it from the stapler 14.
The upper vertical alignment roller 38a is driven by a vertical
alignment upper roller motor 40. The lower vertical matching roller
38b is driven by a vertical alignment lower roller motor 42.
[0031] At the position opposite to the rear end of each of the
sheets P which have been dropped and supplied from the standby tray
10 onto the processing tray 12, a paddle 44 is arranged. The paddle
44, which is configured to be rotatable, aligns vertically the
uppermost sheet P loaded on the processing tray 12. The paddle 44,
as shown in FIG. 6, has a receiving portion 44a for receiving the
sheets P dropped and supplied onto the processing tray 12 from the
standby tray 10, a beating portion 44b for beating down the sheets
P on the processing tray 12, and a feeding portion 44c for aligning
the sheets P on the processing tray 12. The puddle 44 is driven by
a paddle motor 46. The paddle 44 is composed of an elastic rubber
material and has elasticity.
[0032] At the end of the processing tray 12 on the side of the
stapler 14, a stopper 45 for making contact with the rear end of
each of the sheets P and vertically aligning the rear end position
is arranged. Almost at the center of the processing tray 12, a
conveyor belt 50 serving as a sheet discharge mechanism is
installed. The conveyer belt 50 feeds the sheet bundle T, which is
stapled and taken out from the stapler 14 by the upper and lower
vertical alignment rollers 38a and 38b, to first or second sheet
discharge tray 16 or 18. To the conveyer belt 50, a feed pawl 50a
for hooking the rear end of the sheet bundle T is attached. The
first or second sheet discharge tray 16 or 18 is configured to be
slidable on the side surface of the sheet post-processing apparatus
7 in the vertical direction.
[0033] At the end of the processing tray 12 on the side of the
sheet discharge tray 16 or 18, pluralities of alignment rollers 61
are arranged. The alignment rollers 61 are supported by a shaft 60
and contact the bottom surface of the sheet P. The alignment
rollers 61 have a pair of center alignment rollers 61a which are
disposed symmetrically with respect to the conveyor belt 50 and a
pair of side alignment rollers 61b which are disposed on both sides
of the center alignment rollers 61a.
[0034] The alignment rollers 61 are rotated in g direction (first
direction) denoted by the arrow in FIG. 5 to thereby feed the sheet
P to the stopper 45 side so as to allow the rear end of the sheet P
to contact with the stopper 45, thereby vertically aligning the
sheet P. On the other hand, when the alignment rollers 61 are
rotated in h direction (second direction opposite to the first
direction) denoted by the arrow in FIG. 5, the sheet P is fed to
the sheet discharge tray 16 or 18 sides. The alignment rollers 61
and conveyer belt 50 use the same shaft 60. The shaft 60 is made
rotatable in forward and reverse directions by a belt motor 62. The
conveyer belt 50 is driven through a one-way clutch (not shown) and
therefore is rotatable only in t direction denoted by the arrow in
FIG. 5.
[0035] The standby tray 10 can drop and supply the sheets P onto
the processing tray 12 and also can feed the sheets P toward the
first or second sheet discharge tray 16 or 18. The standby tray 10
is so tilted as to support the sheets P such that the position of
the front ends of the sheets P becomes higher than that of the rear
ends thereof. As shown in FIGS. 7 and 8, the standby tray 10 has a
pair of tray members 10a and 10b. The tray members 10a and 10b
receive the sheets in a state that they slide in the width of the
sheet P and support both sides of the sheet P. On the tray members
10a and 10b, standby stoppers 10c and 10d for aligning the rear
ends of the sheets P are installed. The standby tray 10 slides and
moves by a standby tray motor 34.
[0036] The standby tray 10 has pinch rollers 10e which hold the
sheet P on the standby tray 10 between themselves and standby tray
rollers 28 provided for aligning the sheet P and feed it toward the
sheet discharge tray 16 or 18. Note that, without providing the
pinch roller 10e, it is possible to feed the sheet P on the standby
tray 10 toward the sheet discharge tray 16 or 18 only by the
standby tray rollers 28. The standby rollers 28 are controlled by a
standby tray roller drive source 30 in terms of their vertical
movement and rotated by a standby tray roller motor 32.
[0037] Between the standby tray 10 and the processing tray 12,
horizontal alignment plates 47a and 47b shown in FIG. 9 are
installed. When the sheets P are dropped and supplied from the
standby tray 10 onto the processing tray 12, the horizontal
alignment plates 47a and 47b prevent the sheets P from turning away
in the horizontal direction perpendicular to the feeding direction
and horizontally align them. The horizontal alignment plates 47a
and 47b are formed slidably in v direction denoted by the arrow so
as to fit to the width of the sheets P by a horizontal alignment
motor 48.
[0038] The first or second sheet discharge tray 16 or 18 is so
tilted as to support the sheets P such that the position of the
front ends of the sheets P becomes higher than that of the rear
ends thereof. One of the first and second sheet discharge trays 16
and 18 is selected, and the selected one is moved up and down by a
sheet discharge drive section 52. The first or second sheet
discharge tray 16 or 18 is moved up and down up to almost the same
height as that of the sheet discharge section of the standby tray
10 or processing tray 12 when loading the sheets P to improve the
consistency of the sheets P to be discharged. That is, the sheets P
are not disturbed due to a difference in vertical positions.
[0039] At the position below the sheet discharge section of the
processing tray 12 and between the processing tray 12 and sheet
discharge trays 16, 18, a shutter 86 which is a rear end supporting
mechanism for supporting the rear end of the sheet P discharged
onto the sheet discharge trays 16 and is provided. As shown in
FIGS. 10 and 11, the shutter 86 has stationary portions 87 and
movable portions 88. The movable portions 88 can be extended
relative to the stationary portions 87 and can be contracted to
overlap the stationary portions 87 for housing.
[0040] When the sheet P is discharged from the processing tray 12
onto the first or second sheet discharge tray 16 or 18, the movable
portions 88 are contracted to overlap the stationary portions 87,
as shown in FIG. 10. At this time, the upper end of the movable
portions 88 lies at substantially the same height as the upper end
of the stationary portions 87 of the shutter 86.
[0041] In a state where the movable portions 88 are contracted,
center upper portions 86a, which are upper ends of the center area
that faces center alignment rollers 61a of the shutter 86, are
located lower than the peripheral upper portions 86b which are
upper ends of the peripheral area. This configuration allows the
center alignment rollers 61a to be completely exposed from the
upper end of the shutter 86. Therefore, the center portion of the
sheet P that has run over the processing tray 12 and hung there
from, contacts the center alignment rollers 61a without fail.
[0042] When the first or second sheet discharge tray 16 or 18 is
slid, the movable portions 88 of the shutter 86 are extended. At
this time, the movable portions 88 of the shutter 86 are slid in i
direction denoted by the arrow in FIG. 11 while being guided by the
stationary portions 87. The extension/contraction of the moveable
portions 88 of the shutter 86 is controlled by a belt motor 62 for
driving the alignment rollers 61 and conveyer belt 50. The movable
members 88 has a rack- and pinion mechanism which is driven by a
link mechanism for transferring the drive of the belt motor 62 to
the rack. The link mechanism has an electromagnetic clutch and
controls ON/OFF of the electromagnetic clutch to thereby transfer
the drive of the belt motor 62 to the pinion.
[0043] When the electromagnetic clutch is turned ON while the belt
motor 62 drives the alignment rollers 61 in h direction denoted by
the arrow in FIG. 5, the movable portions 88 are slidably extended
in i direction denoted by the arrow in FIG. 11. On the other hand,
when the electromagnetic clutch is turned ON while the belt motor
62 drives the alignment rollers 61 in g direction denoted by the
arrow in FIG. 5, the movable portions 88 are slid in the direction
opposite to the i direction to be contracted. The movable portions
88 can be extended up to the front face of the sheet discharge
section of the processing tray 12 and, further, up to the front
face of the sheet discharge section of the standby tray 10 to
thereby close the sheet discharge sections of the processing tray
12 and standby tray 10. This prevents the sheet P on the sheet
discharge tray 16 or 18 from reversely being fed to the processing
tray 12 or standby tray 10 when the sheet discharge tray 16 or 18
is slid upward with the sheets P loaded thereon.
[0044] Next, the operation of the present invention will be
described. When the sheet is discharged from the processing tray 12
of the sheet post-processing apparatus 7, the shutter 86 is located
below the sheet discharge section of the processing tray 12, as
shown in FIG. 3A. In this state, the sheet P which has been
discharged onto the sheet discharge tray 16 or 18 is supported by
the shutter 86 at the rear end thereof. When the sheet discharge
tray 16 or 18 is slid, the shutter 86 closes the front face of the
sheet discharge sections of the processing tray 12 and standby tray
10 to thereby prevent the sheet P on the sheet discharge tray 16 or
18 from reversely being fed to the processing tray 12 or standby
tray 10, as shown in FIG. 3B.
[0045] After an image has been formed on a sheet P in the image
forming apparatus 5, the sheet P on which an image has been formed
is discharged by the sheet discharge roller 6 of the image forming
apparatus 5 to the sheet post-processing apparatus 7. When
receiving the sheet P, the sheet post-processing apparatus 7
performs a different operation, depending on a case of performing
the post-processing of the sheet P or a case of performing no
post-processing. Or the sheet post-processing apparatus 7 performs
a different operation, depending on a case of that the preceding
sheet P is in execution of the post-processing or that is finished
it.
[0046] When the post-processing is not to be performed, the sheet P
which has been fed from the entrance rollers 22 to the sheet feed
rollers 24 through the sheet path ceiling 36 is fed to the standby
tray 10 by the paper feed rollers 24. Then, the sheet P is moved
down onto the standby tray 10 and is fed while being held between
the standby tray rollers 28 rotated in the direction of the arrow f
and pinch rollers 10e of the standby tray 10 to be discharged onto
the first sheet discharge tray 16 from the sheet discharge section
of the standby tray 10.
[0047] At this time, the sheet discharge tray 16 is slid from
substantially the same height position as the sheet discharge
section of the processing tray 12 in the direction of the arrow j
up to substantially the same height position as the sheet discharge
section of the standby tray 10, as denoted by the dotted line in
FIG. 3B. At the same time, the movable portions 88 are extended in
the direction of the arrow i such that the upper portions 86a and
86b thereof reach the position below the sheet discharge section of
the standby tray 10.
[0048] As a result, the sheet P on the sheet discharge tray 16
which has been discharged from the standby tray 10 is supported by
the extended movable portions 88 of the shutter 86 at the rear end
thereof. The movable portions 88 are extended by the ON operation
of the electromagnetic clutch while the belt motor 62 rotates the
alignment rollers 61 in the direction of the arrow h. At this time,
the shutter 86 is extended such that the center upper portions 86a
become lower than the peripheral upper portions 86b. Therefore,
even if the sheet P is discharged from the standby tray 10 in a
state where its center portion in the feeding direction is
deformed, the deformed portion is not brought into contact with the
shutter 86, thereby avoiding jamming of the sheet P.
[0049] In this way, on the first sheet discharge tray 16, sheets P
directly discharged from the standby tray 10 are sequentially
loaded. The first sheet discharge tray 16 is arranged in a tilted
manner such that the front end of the sheet P is positioned higher
than the rear end thereof, so that, the preceding sheet P loaded on
the first sheet discharge tray 16 is not pressed out by making
contact with the front end of the succeeding sheet P. Namely, the
discharged sheet P is sequentially loaded on the first sheet
discharge tray 16 unless the order is disturbed. Even if the
preceding sheet P is pressed by the succeeding sheet P and is
slightly displaced, the sheet P drops by its own weight to the
shutter 86 side. Therefore, the rear ends of the sheets P are
brought into contact with the shutter 86 on the first sheet
discharge tray 16 and thereby the alignment of the sheets P is
accomplished.
[0050] When the first sheet discharge tray 16 is full, the first
and second sheet discharge trays 16 and 18 are slid in the
direction of the arrow j so that the sheet P is discharged onto the
second sheet discharge tray 18. The movable portions 88 of the
shutter 86 are further extended before the slide of the first and
second sheet discharge trays 16 and 18 to close the sheet discharge
section of the standby tray 10.
[0051] Therefore, it is possible to prevent the sheet P placed on
the first sheet discharge tray 16 from reversely being fed to the
standby tray 10 when the first sheet discharge tray 16 passes the
front face of the standby tray 10. After the second sheet discharge
tray 18 is slid up to the position corresponding to the sheet
discharge section of the standby tray 10, the movable portions 88
are contracted so that the upper portions 86a and 86b of the
shutter 86 are positioned below the sheet discharge section of the
standby tray 10 to open the sheet discharge section of the standby
tray 10. In this state, the sheet P can be discharged from the
standby tray 10 onto the second sheet discharge tray 18.
[0052] Next, a case where staple processing which is a
post-processing is to be performed and no preceding sheets P in
execution of the staple processing remain on the processing tray 12
will be described. At this time, the standby tray 10 slides and
moves the tray members 10a and 10b respectively up to the positions
indicated by the dotted lines in FIG. 12 in the directions of
arrows m and n to open the dropping and supplying path of the sheet
P. The horizontal alignment plates 47a and 47b, to align the sheet
P dropping from the sheet feed rollers 24 in the horizontal
direction, are arranged so that the gap between the horizontal
alignment plates 47a and 47b is made almost equal to the width of
the sheet P. By doing this, the sheet P fed by the sheet feed
rollers 24, without the feeding being obstructed by the standby
tray 10, is dropped and supplied directly onto the processing tray
12.
[0053] At the time of dropping and supplying, the upper vertical
alignment roller 38a is shifted upward. Both sides of the sheet P
drop in contact with the horizontal alignment plates 47a and 47b
and are aligned in the horizontal direction. The rear end of the
first sheet P dropped and supplied onto the processing tray 12 is
placed on the receiving portion 44a of the paddle 44, and the front
end thereof is contact with the alignment rollers 61. Then, the
paddle 44 rotates in the direction of the arrow o, drops the rear
end of the sheet P from the receiving portion 44a, and beats down
it onto the processing tray 12 by the beating portion 44b.
Furthermore, the paddle 44 feeds the sheet P in the direction of
the arrow q by the feeding portion 44c. At the same time, the sheet
P is fed toward the stopper 45 by the alignment rollers 61 rotated
in the direction of the arrow g, and the rear end of the sheet of
paper P is brought into contact with the stopper 45, and the
vertical alignment of the sheet P is accomplished.
[0054] When the sheet P is vertically aligned on the stopper 45
side, the front end of the sheet P hangs outward from the sheet
post-processing apparatus 7 as denoted by the dotted line in FIG.
3A. At this time, the back surface of the sheet P is contact with
the alignment rollers 61 and upper portions 86a and 86b of the
shutter 86. The contact with shutter 86 offers a resistance to the
vertical alignment of the sheet P.
[0055] However, the vertical positions of the center upper portions
86a of the shutter 86 are lower than those of the peripheral upper
portions 86b disposed on both sides of the center upper portions
86a, so that the central alignment rollers 61a are completely
projected upward from the center upper portions 86a of the shutter
86. That is, at the center area, the sheet P is contact with the
center alignment rollers 61a without fail without being affected by
a resistance of the shutter 86. Particularly, in the case of the
sheet P having a large size such as A3 (JIS standard), the center
portion thereof in the feeding direction is easily deformed.
However, even if the center portion of the sheet P has been
deformed, the sheet P can surely receive a feeding force from the
center alignment rollers 61a without being affected by a resistance
of the shutter 86. Thus, the sheet P obtains a satisfactory
vertical alignment by the alignment rollers 61.
[0056] After that, the second or subsequent sheet P is dropped onto
the processing tray 12 with both sides thereof brought into contact
with the horizontal alignment plates 47a and 47b for horizontal
alignment. The second or subsequent sheet P is, after the rear end
thereof is dropped onto the receiving portion 44a of the paddle 44,
fed to the stopper 45 sides only by the rotation of the paddle 44.
The rotation of the paddle 44 brings the rear end of the sheet P
into contact with the stopper 45, thereby accomplishing the
vertical alignment of the sheet P. The vertical alignment of the
sheet P on the processing tray 12 may be performed by moving up and
down the vertical alignment roller 38a for each alignment operation
and by rotating it in the opposite direction to the arrow r.
[0057] In this way, the sheet P on which an image has been formed
is loaded directly on the processing tray 12 from the sheet feed
rollers 24 while sequentially being aligned in the horizontal
direction and vertical direction. When the sheets P reach a
predetermined number, the stapler 14 staples the sheets P on the
processing tray 12 at a desired position and bundles them to form
the sheet bundle T. Thereafter, the upper vertical alignment roller
38a is moved down onto the sheet bundle T. The sheet bundle T is
then held between the upper vertical alignment roller 38a rotated
in the direction of the arrow r and the lower vertical alignment
roller 38b rotated in the direction of the arrow s and is fed
toward the first sheet discharge tray 16.
[0058] When the rear end of the sheet bundle T passes the upper and
lower vertical alignment rollers 38a and 38b, it is hooked by the
feed pawl 50a of the conveyor belt 50 rotated in the direction of
the arrow t and is sent to the first sheet discharge tray 16. At
this time, the alignment rollers 61 are rotated in the direction of
the arrow h. As a result, the sheet bundle T is fed to the sheet
discharge tray 16 or 18 side by feeding forces of both the conveyer
belt 50 and alignment rollers 61. Since the conveyer belt 50 and
alignment rollers 61 use the same shaft 60, they are always driven
at the same time. That is, the feeding forces supplied from the
conveyer belt 50 and alignment rollers 61 are continued to be
applied to the sheet bundle T. As a result, the sheet bundle T is
smoothly and stably fed by means of both the conveyer belt 50 and
alignment rollers 61 onto the sheet discharge tray 16 or 18.
[0059] The first sheet discharge tray 16 is arranged in a tilted
manner and therefore the front end of the sheet P is positioned
higher than the rear end thereof, so that the preceding sheet P
sent to the first sheet discharge tray 16 is not pressed out by
making contact with the front end of the succeeding sheet bundle T.
Further, even if the preceding sheet bundle T is slightly displaced
by the succeeding sheet P, since the first sheet discharge tray 16
is arranged in a tilted manner, the sheet bundle T drops by its own
weight on the shutter 86 side and is loaded on the first sheet
discharge tray 16 with the rear end thereof aligned at the point of
contact with the shutter 86.
[0060] Next, a case where the staple processing which is a
post-processing is to be performed and preceding sheets P in
execution of the staple processing remain on the processing tray 12
will be described. At this time, the standby tray 10 slides and
moves the tray members 10a and 10b from the position indicated by
the dashed line in FIG. 12 respectively in the opposite direction
of the direction of the arrow m and in the opposite direction of
the direction of the arrow n, and is moved to the position
indicated by the solid line shown in FIG. 12, and can support the
sheet P. The standby tray rollers 28 are shifted above the standby
tray 10 so as not to disturb the sheets P. The sheets P discharged
from the image forming apparatus 5 and fed by the sheet feed
rollers 24 are loaded once on the standby tray 10 to wait for the
processing tray 12 to be free.
[0061] After the sheets P are loaded on the standby tray 10, the
standby tray rollers 28 are moved down onto the standby tray 10 and
are rotated in the opposite direction of the direction of the arrow
f. As a result, the sheets P are sent toward the standby stoppers
10c and 10d and are vertically aligned with the rear end of the
sheets P brought into contact with the standby stoppers 10c and
10d.
[0062] Since the standby tray 10 is arranged in a tilted manner, a
force in the direction of the standby stoppers 10c and 10d is
applied to the sheets P by the own weight. Thus, even if, for
example, the succeeding sheet P is fed from the sheet feed rollers
24 in a state that it is curled convexly and is fed to the standby
tray 10, the preceding sheet P loaded on the standby tray 10 is not
pressed out by making contact with the front end of the succeeding
sheet P. Namely, the fed sheet P is sequentially loaded on the
standby tray 10 unless the order is disturbed. Further, even if the
preceding sheet P is pressed by the succeeding sheet P and is
slightly displaced, since the standby tray 10 is arranged in a
tilted manner, the sheet P drops by its own weight down to the
position where the rear end thereof is brought into contact with
the standby stoppers 10c and 10d and is loaded on the standby tray
10 with the rear end aligned.
[0063] During this period, when the preceding sheet P on the
processing tray 12 is discharged on the side of the first sheet
discharge tray 16 and the processing tray 12 becomes free, the
standby tray 10 slides and moves the tray members 10a and 10b
respectively up to the positions indicated by the dotted lines in
FIG. 12 in the directions of the arrows m and n from the position
indicated by the solid line in FIG. 12 via the position indicated
by the alternate long and short dash line in FIG. 12. By doing
this, for example, two sheets P standing by on the standby tray 10,
when the tray members 10a and 10b reach the position indicated by
the alternate long and short dash line in FIG. 12, are dropped and
supplied onto the processing tray 12 from between the tray members
10a and 10b. At this time, the horizontal alignment plates 47a and
47b are arranged so as to make the interval between them almost
equal to the width of the sheets P. Therefore, the sheets P dropped
from the standby tray 10 are controlled on both sides by the
horizontal alignment plates 47a and 47b and are aligned
horizontally.
[0064] The lower side sheet P of the two sheets P dropped onto the
processing tray 12 is sent in the direction of the arrow q by the
lower vertical alignment roller 38b rotated in the opposite
direction of the direction of the arrow s, and the rear end of the
sheet P is brought into contact with the stopper 45, and the
vertical alignment of the sheet P is accomplished. The upper side
sheet P of the two sheets P dropped onto the processing tray 12 is
sent in the direction of the arrow q by the upper vertical
alignment roller 38a rotated in the opposite direction of the
direction of the arrow r, and the rear end of the sheet P is
brought into contact with the stopper 45, and the vertical
alignment of the sheet P is accomplished. Thereafter, the upper
vertical alignment roller 38a is shifted upward.
[0065] The third and subsequent sheets P discharged from the image
forming apparatus 5 are directly dropped and supplied onto the
processing tray 12 from between the tray members 10a and 10b
without standing by on the standby tray 10. Thereafter, the third
and subsequent sheets P are sequentially aligned on the sheets P
loaded earlier on the processing tray 12 by the paddle 44.
[0066] When the sheets P loaded on the processing tray 12 reach a
predetermined number, the sheets P are stapled by the stapler 14 to
form a sheet bundle T. Thereafter, the sheet bundle T is fed toward
the first sheet discharge tray 16 by the upper and lower vertical
alignment rollers 38a and 38b. When the rear end of the sheet
bundle T passes the upper and lower vertical alignment rollers 38a
and 38b, it is hooked by the feed pawl 50a of the conveyor belt 50
and is sent to the first sheet discharge tray 16. At this time, the
alignment rollers 61 are rotated in the direction of the arrow h.
As a result, the sheet bundle T is fed onto the sheet discharge
tray 16.
[0067] Since the conveyer belt 50 and alignment rollers 61 use the
same shaft 60, they are always driven at the same time. That is,
the feeding forces supplied from the conveyer belt 50 and alignment
rollers 61 are continued to be applied to the sheet bundle T. As a
result, the sheet bundle T is smoothly and stably fed by means of
both the conveyer belt 50 and alignment rollers 61 onto the sheet
discharge tray 16 or 18.
[0068] When the first sheet discharge tray 16 is full while the
sheet bundles T are sequentially discharged, subsequent sheet
bundles T are discharged onto the second sheet discharge tray 18 in
place of the first sheet discharge tray 16. In order for the sheet
bundle T to be discharged onto the second sheet discharge tray 18,
the first and second sheet discharge trays 16 and 18 are slid in
the direction of the arrow j. At this time, the movable portions 88
of the shutter 86 are extended in the i direction denoted by the
arrow in FIG. 11 to close the sheet discharge sections of the
processing tray 12 and standby tray 10, as shown in FIG. 3B.
[0069] Therefore, it is possible to prevent the sheet bundle T
placed on the first sheet discharge tray 16 from reversely being
fed to the processing tray 12 or standby tray 10 when the first
sheet discharge tray 16 passes the sheet discharge section of the
processing tray 12 or standby tray 10. After the second sheet
discharge tray 18 is slid up to the position corresponding to the
sheet discharge section of the processing tray 12, the movable
portions 88 of the shutter 86 are contracted to the position shown
in FIG. 10. That is, the movable portions are positioned below the
sheet discharge section of the processing tray 12 to open the sheet
discharge section of the processing tray 12. In this state, the
sheet bundle T can be discharged from the processing tray 12 onto
the second sheet discharge tray 18.
[0070] In this embodiment having such a configuration, when the
staple processing is to be performed after image forming and the
preceding staple processing is not finished on the processing tray
12, the standby tray 10 installed above the processing tray 12
waits for the succeeding sheets P. Thereafter, after the processing
tray 12 becomes free, the sheets P standing by on the standby tray
10 are dropped and supplied and then are moved onto the processing
tray 12. Therefore, the practical feeding path from the standby
tray 10 to the processing tray 12 in the sheet post-processing
apparatus 7 can be shortened and the sheet post-processing
apparatus can be miniaturized.
[0071] Further, the center upper portions 86a of the shutter 86,
which support the rear end of the sheet P discharged onto the sheet
discharge tray 16 or 18 are located lower than the peripheral upper
portions 86b. Therefore, the sheet P can contact the center
alignment rollers 61a without fail on the processing tray 12
without being obstructed by the shutter 86. As a result, the
vertical alignment of the sheet P on the processing tray 12 can be
achieved. Further, even when the movable members 88 of the shutter
86 are extended up to the position corresponding to the sheet
discharge section of the standby tray 10, the center upper portions
86a are located lower than the peripheral upper portions 86b.
Therefore, even if the sheet P is discharged from the standby tray
10 in a state where its center portion in the feeding direction is
deformed, the deformed portion is not brought into contact with the
shutter 86, thereby avoiding jamming of the sheet P.
[0072] Further, in the present embodiment, the alignment rollers 61
and conveyer belt 50 have the same shaft 60. That is, the feeding
forces supplied from the conveyer belt 50 and alignment rollers 61
are continued to be applied to the sheet bundle T. As a result, the
sheet bundle T is effectively be discharged onto the sheet
discharge tray 16 or 18. Further, the movable members 88 of the
shutter 86 are extended while the sheet discharge trays 16 and 18
are slid to close the sheet discharge sections of the processing
tray 12 and/or standby tray 10. Therefore, it is possible to
prevent the sheet P placed on the first sheet discharge tray 16
from reversely being fed to the processing tray 12 or standby tray
10 while the first sheet discharge tray 16 is slid.
[0073] The present invention is not limited to the above embodiment
and various modifications are possible within the scope of the
invention. For example, a method of dropping and supplying the
sheet P from the standby tray to the processing tray is not limited
to one based on the slide movement but may be implemented by a
rotational movement. Further, the post-processing is not limited to
the staple processing, but may be any processing, such as
hole-punching processing in sheets, as far as it is post-processing
to be applied to the sheet.
[0074] The values of the width of the center area of the rear end
supporting mechanism and difference in the vertical position
between the center area and peripheral area thereof is not limited,
and they may be set to any value as far as they fall within a range
where the rear end of the sheet on the sheet discharge tray can
appropriately be supported, where the alignment rollers can be
contact with the back surface of the sheet without fail, and where
the deformed portion is not brought into contact with the rear end
supporting mechanism when the sheet is discharged onto the sheet
discharge tray. Further, a drive means for moving the movable
sections of the rear end supporting mechanism may have any
configuration.
* * * * *