U.S. patent application number 13/542116 was filed with the patent office on 2013-02-28 for sheet processing apparatus and sheet folding method and image forming apparatus.
This patent application is currently assigned to Toshiba Tec Kabushiki Kaisha. The applicant listed for this patent is Hideaki Sugiyama, Yasunobu Terao, Katsuhiko TSUCHIYA. Invention is credited to Hideaki Sugiyama, Yasunobu Terao, Katsuhiko TSUCHIYA.
Application Number | 20130049278 13/542116 |
Document ID | / |
Family ID | 47742508 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130049278 |
Kind Code |
A1 |
TSUCHIYA; Katsuhiko ; et
al. |
February 28, 2013 |
SHEET PROCESSING APPARATUS AND SHEET FOLDING METHOD AND IMAGE
FORMING APPARATUS
Abstract
According to one embodiment, a sheet processing apparatus
pushes, with a folding plate, a sheet bundle held by a stacker into
a nip portion formed by a first folding roller and a second folding
roller and forms a fold. The first folding roller includes a first
folding section configured to come into contact with the second
folding roller and form the nip portion and a first groove
configured to form a gap between the first groove and the second
folding roller in a state in which the first folding section is in
contact with the second folding roller. The first groove is formed
in a position where an end in the width direction of a sheet bundle
of a predetermined size pushed in by the folding plate passes.
Inventors: |
TSUCHIYA; Katsuhiko;
(Shizuoka-ken, JP) ; Sugiyama; Hideaki;
(Shizuoka-ken, JP) ; Terao; Yasunobu;
(Shizuoka-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TSUCHIYA; Katsuhiko
Sugiyama; Hideaki
Terao; Yasunobu |
Shizuoka-ken
Shizuoka-ken
Shizuoka-ken |
|
JP
JP
JP |
|
|
Assignee: |
Toshiba Tec Kabushiki
Kaisha
Tokyo
JP
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
47742508 |
Appl. No.: |
13/542116 |
Filed: |
July 5, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61528705 |
Aug 29, 2011 |
|
|
|
61528678 |
Aug 29, 2011 |
|
|
|
61528682 |
Aug 29, 2011 |
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Current U.S.
Class: |
270/45 |
Current CPC
Class: |
B65H 2511/12 20130101;
G03G 2215/00877 20130101; B65H 45/18 20130101; B65H 2301/4214
20130101; B65H 2511/16 20130101; B42C 1/12 20130101; B65H 2801/27
20130101; B65H 2511/12 20130101; B65H 2301/141 20130101; B65H
2511/16 20130101; B65H 2511/18 20130101; G03G 15/6544 20130101;
B65H 2513/40 20130101; B65H 2513/40 20130101; B65H 31/38 20130101;
B65H 2404/13161 20130101; B65H 2220/03 20130101; B65H 2220/11
20130101; B65H 2220/01 20130101; B65H 2220/02 20130101 |
Class at
Publication: |
270/45 |
International
Class: |
B65H 39/00 20060101
B65H039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 19, 2012 |
JP |
P2012-095258 |
Claims
1. A sheet processing apparatus comprising: a stacker configured to
hold a sheet bundle; and a folding plate configured to push the
sheet bundle held by the stacker into a nip portion formed by the
first folding roller and the second folding roller, wherein the
first folding roller includes a first folding section and a first
groove, the first folding section being configured to come into
contact with the second folding roller and form the nip portion,
and the first groove being configured to form a gap between the
first groove and the second folding roller in a state in which the
first folding section is in contact with the second folding roller
and being formed in a position where an end in a width direction of
a sheet bundle of a predetermined size, on which a fold is formed,
passes, and the second folding roller forms a fold on the sheet
bundle in cooperation with the first folding roller.
2. The apparatus according to claim 1, wherein the second folding
roller includes: a second folding section configured to come into
contact with the first folding section of the first folding roller
and form the nip portion; and a second groove configured to form
the gap between the second groove and the first folding roller in a
state in which the first folding section and the second folding
section are in contact with each other.
3. The apparatus according to claim 2, wherein the second groove is
formed in a position where the end in the width direction of the
sheet bundle of the predetermined size pushed in by the folding
plate passes.
4. The apparatus according to claim 3, wherein the predetermined
size is a plurality of sizes, and a plurality of the first and
second grooves are formed for each of the predetermined sizes.
5. The apparatus according to claim 4, further comprising an
aligning member configured to align, before the sheet bundle is
pushed by the folding plate, a width direction of the sheet bundle
stacked by the stacker.
6. The apparatus according to claim 5, further comprising: an
acquiring section configured to acquire a size of a sheet stacked
on the stacker; and a controller configured to determine whether
the size of the sheet acquired by the acquiring section corresponds
to the predetermined size and, if the acquired size of the sheet
does not correspond to the predetermined size, before the folding
plate pushes the sheet bundle into the nip portion, move the sheet
bundle to a predetermined position where at least one of both ends
in a width direction of the sheet bundle passes the gap.
7. The apparatus according to claim 6, wherein the controller moves
the sheet bundle to the predetermined position via the aligning
member.
8. A sheet processing method for a sheet processing apparatus
including: a first folding roller including a folding section
configured to come into contact with a second folding roller and
form, in a state in which the folding section is in contact with
the second folding roller, a nip portion and a groove configured to
form a gap between the groove and the second folding roller and in
a position where an end in a width direction of a sheet bundle of a
predetermined size passes; and a folding plate configured to push a
sheet bundle held by a stacker into the nip portion and form a
fold, the method comprising: acquiring a size of a sheet of the
sheet bundle; determining whether the acquired size of the sheet
corresponds to the predetermined size; and moving, if the acquired
size of the sheet does not correspond to the predetermined size,
before the folding plate pushes the sheet bundle into the nip
portion, the sheet bundle to a predetermined position where at
least one of both ends in a width direction of the sheet bundle
passes the gap.
9. The method according to claim 8, wherein the second folding
roller includes: a second folding section configured to come into
contact with the first folding section of the first folding roller
and form the nip portion; and a second groove configured to form
the gap between the second groove and the first folding roller in a
state in which the first folding section and the second folding
section are in contact with each other.
10. The method according to claim 8, further comprising aligning a
width direction of a sheet bundle stacked by the stacker before the
folding plate pushes the sheet bundle.
11. The method according to claim 10, further comprising moving the
sheet bundle to the predetermined position with an aligning member
configured to align the width direction of the sheet bundle stacked
by the stacker.
12. An image forming apparatus comprising: an image forming section
configured to form an image on a sheet; a stacker configured to
hold a sheet bundle subjected to image formation; a folding plate
configured to push the sheet bundle held by the stacker into a nip
portion formed by the first folding roller and the second folding
roller, wherein the first folding roller includes a first folding
section and a first groove, the first folding section being
configured to come into contact with the second folding roller and
form the nip portion, and the first groove being configured to form
a gap between the first groove and the second folding roller in a
state in which the first folding section is in contact with the
second folding roller and being formed in a position where an end
in a width direction of a sheet bundle of a predetermined size, on
which a fold is formed, passes, and the second folding roller forms
a fold on the sheet bundle in cooperation with the first folding
roller.
13. The apparatus according to claim 12, wherein the second folding
roller includes: a second folding section configured to come into
contact with the first folding section of the first folding roller
and form the nip portion; and a second groove configured to form
the gap between the second groove and the first folding roller in a
state in which the first folding section and the second folding
section are in contact with each other.
14. The apparatus according to claim 13, wherein the second groove
is formed in a position where the end in the width direction of the
sheet bundle of the predetermined size pushed in by the folding
plate passes.
15. The apparatus according to claim 14, wherein the predetermined
size is a plurality of sizes, and a plurality of the first and
second grooves are formed for each of the predetermined sizes.
16. The apparatus according to claim 15, further comprising an
aligning member configured to align, before the sheet bundle is
pushed by the folding plate, a width direction of the sheet bundle
stacked by the stacker.
17. The apparatus according to claim 16, further comprising: an
acquiring section configured to acquire a size of a sheet stacked
on the stacker; and a controller configured to determine whether
the size of the sheet acquired by the acquiring section corresponds
to the predetermined size and, if the acquired size of the sheet
does not correspond to the predetermined size, before the folding
plate pushes the sheet bundle into the nip portion, move the sheet
bundle to a predetermined position where at least one of both ends
in a width direction of the sheet bundle passes the gap.
18. The apparatus according to claim 17, wherein the controller
moves the sheet bundle to the predetermined position via the
aligning member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior U.S. patent application No. 61/528,705,
filed on Aug. 29, 2011, and the prior U.S. Patent Application No.
61/528,678, filed on Aug. 29, 2011, and the prior U.S. Patent
Application No. 61/528,682, filed on Aug. 29, 2011, and Japanese
Patent Application No2012-95258, filed on Apr. 19, 2012, and the
entire contents all of which are incorporated herein by
reference.
FIELD
[0002] Embodiments described herein relate generally to a sheet
processing apparatus, a sheet folding method, and an image forming
apparatus for performing folding of printed sheets.
BACKGROUND
[0003] There is a sheet finishing apparatus that is set on a
downstream side in a sheet conveying direction of an image forming
apparatus such as a copying machine, a printer, or a
multi-functional peripheral (MFP) and applies finishing such as
punching or stapling to printed sheets. The sheet finishing
apparatus includes a function of folding for folding a part of
sheets and a function of saddle stapling and saddle folding for
folding sheets in the center after stapling the center of the
sheets with staples in addition to functions of punching and
stapling. The function of saddle stapling and saddle folding can
produce (bind) a booklet from printed plural sheets.
[0004] In the saddle stapling and saddle folding, the sheet
finishing apparatus forms a fold and folds a stapling portion of
sheets with a pair of rollers called a folding roller pair after
stapling the center of sheets with staples. For example, the sheet
finishing apparatus strikes a tabular member called a folding blade
against a stapling portion of a sheet bundle and pushes the sheet
bundle into a nip portion of the folding roller pair to fold the
sheet bundle.
[0005] However, in the apparatus in the past, when the sheet bundle
is folded in the nip portion of the roller pair, the sheets
sometimes wave. In other words, it is likely that the sheet bundle
is directly folded by a strong pressing force, whereby creases
occur in the sheet bundle.
[0006] Therefore, there is a demand for a sheet processing
apparatus that more appropriately performs the folding than the
sheet processing apparatus including the folding unit in the
past.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a block diagram for explaining a hardware
configuration of an image forming apparatus and a sheet processing
apparatus according to a first embodiment;
[0008] FIG. 2 is a schematic diagram for explaining the
configuration of the sheet processing apparatus in the first
embodiment;
[0009] FIGS. 3A to 3D are schematic diagrams for explaining a
lateral alignment member in the first embodiment;
[0010] FIG. 4 is a schematic perspective view for explaining a
folding unit in the first embodiment;
[0011] FIG. 5 is a schematic diagram for explaining a folding
roller pair in the first embodiment;
[0012] FIG. 6 is a flowchart for explaining folding by the sheet
processing apparatus in the first embodiment; and
[0013] FIGS. 7A to 7D are schematic diagrams for explaining folding
in a second embodiment.
DETAILED DESCRIPTION
[0014] Exemplary embodiments are explained in detail below with
reference to the accompanying drawings.
First Embodiment
[0015] In general, according to one embodiment, a sheet processing
apparatus includes: a stacker configured to hold a sheet bundle; a
first folding roller; a second folding roller; and a folding plate
configured to push the sheet bundle held by the stacker into a nip
portion formed by the first folding roller and the second folding
roller and forma fold. The first folding roller includes: a first
folding section configured to come into contact with the second
folding roller and form the nip portion; and a first groove
configured to form a gap between the first groove and the second
folding roller in a state in which the first folding section is in
contact with the second folding roller. The first groove is formed
in a position where an end in the width direction of a sheet bundle
of a predetermined size pushed in by the folding plate passes.
[0016] FIG. 1 is a block diagram for explaining a hardware
configuration of an image forming apparatus and a sheet processing
apparatus. An image forming apparatus 100 includes a controller
102, a storage device 108, a communication interface (communication
I/F) 110, an operation panel 112, a scanner 114 that reads an
original document, and a printer (an image forming section) 116
that forms an image. The components of the image forming apparatus
100 are connected via a bus 118.
[0017] The controller 102 includes a processor 104 including a CPU
(Central Processing Unit) or an MPU (Micro Processing Unit) and a
memory 106. The memory 106 is, for example, a semiconductor memory.
The memory 106 includes a ROM (Read Only Memory) having stored
therein control programs and the like and a RAM (Random Access
Memory) that provides the processor 104 with a temporary work area.
The controller 102 controls the operation panel 112, the scanner
114, and the printer 116 on the basis of various computer programs
and the like stored in the ROM or the storage device 108. The
controller 102 includes a function of correcting or expanding image
data. The controller 102 communicates with a controller 202 of a
sheet processing apparatus 200.
[0018] The storage device 108 stores application programs and an
OS. The application programs include computer programs for
executing functions of a multifunction peripheral such as a copy
function, a print function, a scanner function, a facsimile
function, and a network file function. The application programs
further include an application for a Web client (a Web browser) and
other applications.
[0019] The storage device 108 temporarily stores image data of an
original document read by the scanner 114, image data acquired via
the communication I/F 110, or the like. Further, the storage device
108 appropriately stores software update, a protected electronic
document, text data, account information, policy information, and
the like. The storage device 108 may be, for example, a magnetic
storage device such as a hard disk drive, an optical storage
device, a semiconductor storage device (a flash memory, etc.), or
an arbitrary combination of these storage devices.
[0020] The communication I/F 110 is an interface connected to an
external apparatus. The communication I/F 110 is connected to an
external apparatus via appropriate radio or wire of IEEE802.15,
IEEE802.11, IEEE802.3, IEEE1284, or the like for, for example,
Bluetooth (registered trademark), infrared connection, or optical
connection. The communication I/F 110 may further include a USB
connection section to which a connection terminal of the USB
standard is connected and a parallel interface. The controller 102
communicates with a user terminal, a USB device, and other external
apparatuses via the communication I/F 110.
[0021] The operation panel 112 includes a display section of a
touch panel type and various operation keys. The operation keys
include, for example, a ten key, a reset key, a stop key, and a
start key. The display section displays instruction items
concerning printing conditions such as a sheet size, the number of
copies, printing density setting, and finishing (stapling or
folding). Instructions of the displayed items are input from the
display section.
[0022] The scanner 114 includes an incorporated scanning and
reading unit that reads an original document as an image, a
document placing table, and an auto document feeder that conveys
the original document to a reading position. The scanning and
reading unit of the scanner 114 reads an original document set on
the document placing table or the auto document feeder.
[0023] The printer 116 includes a publicly-known image forming unit
including, for example, a photoconductive drum and a publicly-known
developing unit by, for example, toner. The printer 116 forms,
using these units, an image corresponding to image data of an
original document read by the scanner 114 or an image corresponding
to image data sent from the user terminal on a sheet.
[0024] The sheet processing apparatus 200 includes the controller
202, a finisher 220, and a saddle unit section 240. The controller
202 includes a processor 204 including a CPU (Central Processing
Unit) or an MPU (Micro Processing Unit) and a memory 206. The
memory 206 is, for example, a semiconductor memory. The memory 206
includes a ROM (Read Only Memory) having stored therein control
programs and the like and a RAM (Random Access Memory) that
provides the processor 204 with a temporary work area. The
controller 202 communicates with the controller 102 of the image
forming apparatus 100. The controller 202 controls the finisher 220
and the saddle unit section 240 on the basis of information
received from the controller 102 and various computer programs and
the like stored in the ROM and the like. The saddle unit section
240 includes a stapler 252, a folding unit 258, and a fold
reinforcing unit 263.
[0025] FIG. 2 is a schematic diagram for explaining the
configuration of the sheet processing apparatus. The sheet
processing apparatus 200 processes, according to an instruction
input from the operation panel 112 or an instruction from the user
terminal, a sheet discharged from the image forming apparatus 100.
The sheet processing apparatus 200 includes an inlet roller 210, a
diverting member 212, the finisher 220, and the saddle unit section
240. The inlet roller 210 carries a sheet, which is carried out
from the image forming apparatus 100, into the sheet processing
apparatus 200. The diverting member 212 switches, according to a
processing content input via the display section of the operation
panel 112 of the image forming apparatus 100 shown in FIG. 1, a
conveying destination of the sheet carried in by the inlet roller
210 to the finisher 220 or the saddle unit section 240. For
example, the finisher 220 sorts a sheet bundle or staples an end of
the sheet bundle.
[0026] The saddle unit section 240 staples or folds a sheet bundle.
The saddle unit section 240 includes plural conveying rollers 242,
a carry-out roller 244, a carry-out roller sensor 245, a stacking
section 246, the stapler 252, the folding unit 258, the fold
reinforcing unit 263, a discharge roller 264, and a sheet bundle
stacking tray 266. The conveying rollers 242 convey a sheet to the
stacking section 246. The carry-out roller 244 carries out the
sheet to the stacking section 246. The carry-out roller sensor 245
detects the conveyed sheet.
[0027] The stacking section 246 includes a stack tray 248, stackers
250, and a sensor 251. A sheet is temporarily stacked on the
stacking section 246 in an upright position. The stack tray 248
supports the surface of the sheet. The stackers 250 receive the
lower end of the sheet. The stackers 250 support the lower end of
the sheet stacked in the upright position and align (longitudinally
align) the position of the end of the sheet in a conveying
direction. The sheet stacked on the stacking section 246 is also
aligned in the width direction crossing the sheet conveying
direction. The alignment in the width direction (lateral alignment)
of the sheet is explained below. The sensor 251 detects that sheet
is conveyed to the stackers 250.
[0028] The stackers 250 move up and down along the stack tray 248.
The stackers 250 adjust the position of sheets stapled by the
stapler 252 and the position of sheets folded by the folding unit
258. In the explanation of this embodiment, as an example, the
stapling position of the sheets and the folding position of the
sheets are assumed to be a center portion in the sheet conveying
direction.
[0029] Plural (two) staplers 252 are arranged side by side in the
width direction of a sheet. The stapler 252 includes a stapler head
254 and an anvil 256. The stapler head 254 and the anvil 256 staple
a sheet bundle.
[0030] When the stapler 252 staples the sheet bundle, the stackers
250 move to set a stapled position of sheets to a folding position
by the folding unit 258. When the stackers 250 stop, the folding
unit 258 starts folding.
[0031] The folding unit 258 includes a folding plate 260 and a
folding roller pair 262. The folding plate 260 stays on standby in
a position where the folding plate 260 does not hinder conveyance
of a sheet. When a position where a fold should be formed comes to
the front of the folding plate 260, the folding plate 260 moves
toward the folding roller pair 262. The distal end of the folding
plate 260 thrusts the sheet bundle and pushes the sheet bundle to a
nip portion of the rotating folding roller pair 262. The folding
roller pair 262 compresses, conveys, and folds the sheets pushed by
the folding plate 260. The sheet bundle having the fold formed
thereon by the folding unit 258 is further conveyed to the fold
reinforcing unit 263 provided further on a downstream side of the
folding unit 258.
[0032] The fold reinforcing unit 263 moves while pressurizing the
fold in the width direction crossing the conveying direction of the
sheet bundle (a direction along the line of the fold) and
reinforces the fold formed by the folding unit 258 (reinforcing).
The sheet bundle having the fold reinforced by the fold reinforcing
unit 263 is discharged to the sheet bundle stacking tray 266 by the
discharge roller 264.
[0033] Alignment in the width direction crossing the conveying
direction of the sheet stacked on the stacking section 246
(hereinafter, lateral alignment) is explained. FIGS. 3A to 3D are
schematic diagrams for explaining a lateral alignment member. The
stacking section 246 includes the stackers 250 and a lateral
alignment member 300. The lateral alignment member 300 includes a
first aligning member 302a and a second aligning member 302b,
horizontally suspended members 304a and 304b, a pinion gear 306,
and a motor Ml.
[0034] The first aligning member 302a and the second aligning
member 302b are opposed in parallel to each other. The first
aligning member 302a and the second aligning member 302b align ends
in the width direction (lateral ends) of a sheet stacked on the
stackers 250.
[0035] The horizontally suspended members 304a and 304b are
respectively connected to the first aligning member 302a and the
second aligning member 302b. The horizontally suspended members
304a and 304b are opposed in parallel to each other. The
horizontally suspended members 304a and 304b respectively include
racks on opposed surfaces thereof. The pinion gear 306
simultaneously meshes with the racks of the respective horizontally
suspended members 304a and 304b. The motor M1 rotates the pinion
bear 306 via a gear 107. The pinion gear 306 rotates to slide the
horizontally suspended members 304a and 304b in opposite directions
to each other in the width direction of the sheet. The motor M1 may
be, for example, a stepping motor. A detecting member 308 detects
the positions in the sheet width direction of the first aligning
member 302a and the second aligning member 302b. The detecting
member 308 may be, for example, a micro sensor or a micro actuator.
In this embodiment, the detecting member 308 detects that the first
aligning member 302a and the second aligning member 302b are in
home positions (HPs; first positions). A state in which the first
aligning member 302a and the second aligning member 302b are in the
HPs is referred to as a state in which the first aligning member
302a and the second aligning member 302b are open in the width
direction, i.e., an open state. The positions of the first aligning
member 302a and the second aligning member 302b are controlled with
reference to the HPs according to the number of pulses given to the
motor M1 in order to drive the first and second aligning members
302a and 302b. When the controller 202 receives an instruction for
folding or saddle stapling or saddle folding from the operation
panel 112 or an external apparatus, the controller 202 laterally
aligns a sheet with the lateral alignment member 300. After the
lateral alignment by the lateral alignment member 300, the
controller 202 staples a sheet bundle with the stapler 252 or folds
the sheet bundle with the folding unit 258.
[0036] In FIG. 3A, a state in which the first aligning member 302a
and the second aligning member 302b are present in the first
positions is shown. In ideal conveyance posture, a sheet P1 is
conveyed in a state in which the center of a space between the
first aligning member 302a and the second aligning member 302b and
the center in the width direction of the conveyed sheet P1 coincide
with each other. The first aligning member 302a and the second
aligning member 302b are respectively on standby in the first
positions away from the lateral ends of the sheet P1, which is
conveyed in the ideal conveyance posture, by a first distance. The
first distance may be, for example, 15 mm. The first positions may
be positions to which the first aligning member 302a and the second
aligning member 302b are moved from the HPs by applying a
predetermined number of pulses to the motor M1 and rotating the
motor M1.
[0037] The first aligning member 302a and the second aligning
member 302b move in directions indicated by arrows B in FIG. 3B to
come close to the lateral ends of the conveyed sheet P1 and
laterally align the sheet P1. For example, the first aligning
member 302a and the second aligning member 302b move to come close
to the lateral ends of the sheet P1 after the lower end of the
sheet P1 reaches the position between the first aligning member
302a and the second aligning member 302b. For the lateral
alignment, for example, the first aligning member 302a and the
second aligning member 302b move to second positions where the
distance between the first aligning member 302a and the second
aligning member 302b is equal to the length in the width direction
of the sheet (a second distance).
[0038] After the lateral alignment, as indicated by arrows C in
FIG. 3C, the first aligning member 302a and the second aligning
member 302b move to third positions away from the lateral ends of
the sheet P1 by a third distance. The first aligning member 302a
and the second aligning member 302b wait for the following sheet P2
in the third positions. The third distance may be shorter than the
first distance. The third distance may be, for example, 3 mm.
[0039] The first aligning member 302a and the second aligning
member 302b move in directions indicated by arrows D in FIG. 3D to
come close to the lateral ends of the conveyed sheet P2 and
laterally align a sheet bundle including the sheet P1 and the sheet
P2. For example, the first aligning member 302a and the second
aligning member 302b move to come close to the lateral ends of the
sheet P2 after the lower end of the sheet P2 reaches the position
between the first aligning member 302a and the second aligning
member 302b. The first aligning member 302a and the second aligning
member 302b move to, for example, the second positions in order to
perform the lateral alignment. The lateral alignment member 300
repeats the abovementioned actions every time a sheet is conveyed
and laterally aligns a sheet bundle including the sheets P1 and P2
and the following sheets.
[0040] FIG. 4 is a schematic perspective view for explaining the
overall structure of the folding unit 258. In FIG. 4, an arm 270
and a driving section 282 including a groove cam 286 on one side
(the near side in the figure) are omitted.
[0041] The folding unit 258 includes a folding roller pair 262 that
folds a sheet bundle into two, a comb teeth-like folding plate 260
that pushes the sheet bundle into a nip portion of the folding
roller pair 262, and a guide member 280 that holds the folding
plate 260 to be movable to the folding roller pair 262.
[0042] The folding roller pair 262 includes a fixed roller 262a and
a movable roller 262b. The fixed roller 262a is fixedly arranged in
a not-shown apparatus frame to be rotatable via a shaft. The
movable roller 262b is rotatably supported at one end 270b of the
arm 270 supported in the not-shown apparatus frame to be pivotable
about a fulcrum 270a. The movable roller 262b can come into contact
with and separate from the fixed roller 262a. A spring 272 is
attached to the other end 270c of the arm 270. The movable roller
262b urged by the arm 270, which pivots about the fulcrum 270a,
comes into press contact with the fixed roller 262a and forms a nip
portion. The fixed roller 262a and the movable roller 262b are
rotated by a not-shown driving motor.
[0043] The folding plate 260 includes a protrusion section 274 and
a shaft 276. The folding plate 260 is slidably held by the guide
member 280 via the protrusion section 274 and the shaft 276. The
guide member 280 includes a guide groove 280a for slidably
supporting the protrusion section 274 and the shaft 276 and guiding
the folding plate 260 to the nip portion of the folding roller pair
262. The driving sections 282 that slide the folding plate 260 are
connected to both the ends of the shaft 276.
[0044] The driving section 282 includes a cam shaft 284, the groove
cam 286 that rotates about the cam shaft 284, and a link member
288. The groove cam 286 includes a groove 286a. A roller 287 such
as a roller follower, which is a contact piece, is rotatably guided
into the groove 286a of the groove cam 286. The roller 287 is
attached to the link member 288. A link pivot shaft 290 is provided
at one end of the link member 288. The link pivot shaft 290 is
attached to the apparatus frame. The groove cam 286 is rotated by a
not-shown driving motor connected to one end of the cam shaft 284.
When the roller 287 is guided along the groove 286a according to
the rotation of the groove cam 286, the link member 288 repeats a
reciprocating action like a pendulum action about the link pivot
shaft 290 according to the eccentricity of the groove 286a. The
folding plate 260 slides along the guide groove 280a of the guide
member 280 according to the reciprocating action of the link member
288. The distal end of the folding plate 260 thrusts a sheet bundle
and pushes the sheet bundle to the nip portion of the rotating
folding roller pair 262. The folding roller pair 262 compresses,
conveys, and folds sheets pushed by the folding plate 260.
[0045] FIG. 5 is a schematic diagram for explaining the folding
roller pair 262. The fixed roller 262a and the movable roller 262b
of the folding roller pair 262 are formed at the length equal to
the width of a largest sheet that can be processed by the sheet
processing apparatus.
[0046] The fixed roller 262a of the folding roller pair 262
includes first folding sections 292, which are areas having a
roller diameter of r1, and first grooves 293, which are areas
having a roller diameter of r2 (r1>r2). The first folding
sections 292 come into contact with the movable roller 262b and
form nip portions. The first grooves 293 form gaps between the
first grooves 293 and the movable roller 262b in a state in which
the first folding sections 292 are in contact with the movable
roller 262b.
[0047] The movable roller 262b includes second folding sections
294, which are areas having a roller diameter of r1, and second
grooves 295, which are areas having a roller diameter of r2
(r1>r2). The second folding sections 294 come into contact with
the first folding sections 292 of the fixed roller 262a and form
nip portions. The second grooves 295 form gaps in a state in which
the first folding sections 292 and the second folding sections 294
form the nip portions. The first grooves 293 and the second grooves
295, which form the gaps, are arranged such that the distal end of
the comb teeth-like folding plate 260 enters the gaps.
[0048] The first grooves 293 and the second grooves 295 are formed
to correspond to the size of sheets pushed in by the folding plate
260. In other words, the first grooves 293 and the second grooves
295 are formed in positions where ends in the width direction of a
sheet of a predetermined size crossing the sheet conveying
direction pass during folding. If the predetermined size is plural
sizes, plural first grooves 293 and plural second grooves 295 are
formed for each of the predetermined sizes.
[0049] When a sheet bundle is pushed into the nip portions of the
folding roller pair 262 by the folding plate 260, force applied to
sheets is different in a pressed portion and a portion nipped by
the folding roller pair 262. After forming a fold on the sheet
bundle with the folding roller pair 262, the sheet bundle is
conveyed by the folding roller pair 262. Consequently, it is likely
that a bend occurs during the conveyance and creases are formed on
the sheets. In particular, in a state in which the ends in the
width direction of the sheets are nipped, the bend may not be able
to sufficiently escape.
[0050] Therefore, in the fixed roller 262a and the movable roller
262b of the folding roller pair 262 in this embodiment, grooves are
formed to prevent the ends in the width direction of the sheet
bundle from being nipped by the folding roller pair 262. Portions
of the sheet bundle several millimeters from the sheet ends are
prevented from being nipped by the rollers, whereby the bend that
occurs in the sheet bundle surely escape from the ends of the sheet
bundle. Therefore, it is possible to prevent the occurrence of the
creases.
Modification of the First Embodiment
[0051] In the first embodiment, the sheet ends are not nipped by
the folding roller pair 262. However, in a modification of the
first embodiment, sheet ends of a sheet other than the sheet of the
predetermined size for which the corresponding grooves are formed
(hereinafter, irregular-size sheet) are not nipped either.
[0052] FIG. 6 is a flowchart for explaining folding in this
modification. In ACT 601, the controller (an acquiring section) 202
acquires a size of a sheet conveyed to the stackers 250. The
controller 202 may acquire the sheet size from the controller 102
of the image forming apparatus 100, may detect the sheet size using
a detecting member provided in a conveying path of the sheet
processing apparatus 200, or may detect the sheet size using a
detecting member that detects ends of the sheet in a publicly-known
punch unit. Alternatively, a detecting member that detects the size
of the sheet conveyed to the stackers 250 may be arranged.
[0053] In ACT 602, the controller 202 drives the lateral alignment
member 300 to align the width direction of the sheet conveyed to
the stackers 250. The controller 202 determines whether a last
sheet of a sheet bundle to be folded is conveyed to the stackers
250 (ACT 603). If the sheet is not the last sheet of the sheet
bundle (No in ACT 603), the controller 202 returns to ACT 602 and
performs lateral alignment every time a sheet is conveyed to the
stackers 250.
[0054] On the other hand, if the lateral alignment is completed in
a state in which the last sheet of the sheet bundle is conveyed to
the stackers 250 (Yes in ACT 603), the controller 202 determines,
on the basis of acquired information concerning the sheet size,
whether sheets are sheets of the predetermined size corresponding
to the grooves formed in the rollers of the folding roller pair 262
(ACT 604). If the sheets are the sheets of the predetermined size
(Yes in ACT 604), the controller 202 pushes laterally-aligned
sheets into the folding roller pair 262 with the folding plate 260
and performs folding (ACT 605).
[0055] On the other hand, if the sheet size of the sheet bundle
stacked on the stackers 250 is not the predetermined size (No in
ACT 604), the controller 202 slides the first aligning member 302a
and the second aligning member 302b in the sheet width direction
and shifts the sheet bundle (ACT 606). The controller 202 shifts
the sheet bundle such that at least one of both ends of a sheet
bundle of an irregular size is located in the first groove 293 and
the second groove 295 of the folding roller pair 262. After
shifting the sheet bundle in the width direction via the lateral
alignment member 300, the controller 202 pushes the sheet bundle
into the folding roller pair 262 with the folding plate 260 and
performs the folding (ACT 605). At least one of both the ends in
the width direction of the sheet bundle passes the gap formed by
the first groove 293 and the second groove 295.
[0056] In this modification, even if the irregular-size sheets
other than the sheets of the predetermined size corresponding to
the grooves formed in the rollers of the folding roller pair 262
are processed, the position of the sheet bundle is adjusted such
that at least one of both the ends of the sheet bundle is located
in the grooves of the folding roller pair 262. Consequently, it is
possible to realize the same effects as the effects of the first
embodiment.
Second Embodiment
[0057] FIGS. 7A to 7D are schematic diagrams for explaining folding
in a second embodiment. As shown in FIG. 7A, the folding plate 260
of the sheet processing apparatus 200 pushes a sheet bundle stacked
on the stackers 250 into the nip portion of the folding roller pair
262. Subsequently, as shown in FIG. 7B, the folding roller pair 262
presses the sheet bundle, which is pushed in by the folding plate
260, with the fixed roller 262a and the movable roller 262b and
forms a fold on the sheet bundle.
[0058] As shown in FIG. 7C, after forming the fold on the sheet
bundle with the folding roller pair 262, the controller 202 of the
sheet processing apparatus 200 according to this embodiment once
displaces the movable roller 262b in the direction opposite to the
fixed roller 262a. In other words, the controller 202 reduces or
eliminates a nip (a fold load) of the sheet bundle by the folding
roller pair 262 to thereby allow a bend of the sheet bundle to
escape and prevent occurrence of creases. The movable roller 262b
does not have to be separated from the sheet bundle. For example,
the movable roller 262b may be displaced such that a pressing force
of the movable roller 262b on the fixed roller 262a decreases to be
smaller than a pressing force (a load) for forming a fold.
[0059] As shown in FIG. 7D, the controller 202 displaces the
movable roller 262b to the fixed roller 262a side and presses the
sheet bundle, on which the fold is formed, with the fixed roller
262a and the movable roller 262b again. The fixed roller 262a and
the movable roller 262b convey the nipped sheet bundle downstream
in the sheet conveying direction.
[0060] With the sheet processing apparatus according to this
embodiment, it is possible to allow a bend that occurs in a sheet
bundle to escape and prevent occurrence of creases.
[0061] According to at least one of the embodiments explained
above, it is possible to perform more appropriate folding.
[0062] An entity that executes the operations in the embodiments is
an entity related to a computer such as hardware, a complex of the
hardware and software, the software, and the software being
executed. The entity that executes the operations is a process
executed on a processor, the processor, an object, an execution
file, a thread, a computer program, and the computer but is not
limited to these. The process or the thread may be caused to play
plural entities that execute the operations.
[0063] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of invention. Indeed, the novel
apparatus described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the apparatus described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *