Information
-
Patent Grant
-
6644643
-
Patent Number
6,644,643
-
Date Filed
Tuesday, January 29, 200222 years ago
-
Date Issued
Tuesday, November 11, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 270 5808
- 399 410
- 227 110
- 227 111
- 227 99
- 227 100
- 227 150
- 227 154
- 227 155
-
International Classifications
-
Abstract
A sheet processing apparatus for processing a sheet bundle includes a stitching unit having a head portion for driving staples into the sheet bundle and an anvil portion for receiving and bending the staples driven by the head portion, a feeding device for feeding the sheet bundle to a stitching position between the head portion and the anvil portion, a transport device for transporting the stitching unit to a position perpendicular to a sheet bundle feeding direction, a guide member for guiding the sheet bundle to the stitching position, and a supplement guide member. The supplement guide member retracts to a position that does not hinder the movement of the stitching unit when the stitching unit moves, and guides the sheet bundle to the guide member without a leading edge of the sheet bundle touching the upstream edge of the guide member.
Description
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a sheet processing apparatus and an image reading apparatus, in particular it relates to an apparatus for performing a sheet bundle binding process.
Conventionally, an image forming apparatus such as a copier, a printer, a facsimile machine and other devices that combine them have a sheet processing apparatus that stacks a bundle of sheets discharged from the image forming apparatus and staples (binding process) the bundle.
Some of such apparatuses are provided with a stitching unit comprising a head to drive staples and an anvil to receive and bend the staples to bind a bundle of sheets substantially in a center area thereof.
An example of such a sheet processing apparatus, as disclosed in Japanese Patent Publication 07-157180, has a partial guide attached directly to a head and an anvil to guide a bundle to pass between them.
Nonetheless, in a conventional sheet processing apparatus, the guide is extended traversing a moving direction of a bundle when a bundle passes through a transport path between the head and the anvil. The guide also extends parallel to the bundle surface opposite to the head and anvil, i.e. a width direction of the bundle. In this case, it is not possible to guide and support the bundle completely across its width direction. Therefore, an edge of the bundle in the width direction tends to droop down or get caught on other internal parts upon transporting or stitching. As a result, an accurate positioning of the bundle is obstructed, causing undesirable stitching.
If a guide is attached substantially across an entire region in a width direction of the bundle, it is possible to guide and support the bundle throughout the entire width direction. But a leading edge of the bundle is easy to get caught in a gap between the head, the anvil and the guide, causing inaccurate positioning of the bundle and improper binding of the bundle.
An object of the present invention, in view of the problems of the current technology, is to provide a sheet processing apparatus and an image reading apparatus that securely transports and properly stitches a bundle.
Further objects and advantages of the invention will be apparent from the following description of the invention.
SUMMARY OF THE INVENTION
The present invention provides a sheet processing apparatus comprising a stitching unit having a head to drive staples into a bundle of sheets and an anvil to receive and bend the staples driven from the head. When the bundle is to be stitched, the stitching unit moves perpendicular to a direction that the bundle is transported. The sheet processing apparatus according to the present invention also comprises a guide member attached between the head and the anvil to guide the bundle to a stitching position, and a supplement sheet guide member disposed upstream side of the guide member in a transport direction of the bundle. The supplement sheet guide will not contact a leading edge of the bundle, and retracts so that the supplement sheet guide does not hinder movements of the stitching unit when the stitching unit moves.
The supplement guide member can have an inclined contact portion that touches the stitching unit. When the stitching unit moves, the stitching unit abuts the inclined contact portion, and the supplement guide unit retracts not to obstruct the movement of the stitching unit.
In another aspect of this invention, the stitching unit has a roller that contacts the inclined contact portion.
The supplement guide member may be disposed on an upstream in a transport direction of the bundle where the supplement guide does not interfere with the movement of the stitching unit upon retracting.
The supplement guide member may be attached to the stitching unit so that when the stitching unit moves to a predetermined position, the supplement guide member retracts to a position where the supplement guide member does not interfere with movements of the stitching unit.
The sheet feeding apparatus of the invention can include an aligning means to align in a direction traversing a transport direction of the bundle; a moving means to move the stitching unit in a direction traversing a transport direction of the bundle; and a control means to control the moving means to adjust the position of the supplement guide member.
One aspect of the present invention provides an image forming apparatus comprising an image forming unit and a sheet processing apparatus for stitching the bundle of sheets with images formed by the image forming apparatus. The sheet processing apparatus can be the one described in any of the aspects mentioned above.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a view for a copier that has an image forming apparatus with a sheet processing apparatus according to the present invention;
FIG. 2
is a side cross-section view of the sheet processing apparatus in
FIG. 1
;
FIG. 3
is a top view of a processing tray of the sheet post-processing apparatus in
FIG. 1
;
FIG. 4
is a front view of a stopper disposed in the sheet processing apparatus in
FIG. 1
;
FIG. 5
is a front view of a stopper disposed in the sheet processing apparatus in
FIG. 1
;
FIG. 6
is a perspective view of a saddle-stitching unit disposed in the sheet processing apparatus in
FIG. 1
;
FIG. 7
is a view of an attachment block, a guide base block, and a head housing of the saddle-stitching unit;
FIG. 8
is a processing diagram of the sheet processing apparatus in
FIG. 1
;
FIG. 9
is a view of another attachment block, a guide base block, and a head housing of the saddle-stitching unit in
FIG. 7
;
FIG. 10
is a view of a gap-detecting sensor disposed on the stitching unit;
FIG. 11
is a view of a detecting operation of the gap-detecting sensor in
FIG. 10
;
FIG. 12
is a top view of a transfer belt of the sheet processing apparatus in
FIG. 1
;
FIG. 13
is a view of a home position of the saddle-stitching unit in
FIG. 7
;
FIG. 14
is a front view of the saddle-stitching unit in
FIG. 7
;
FIG. 15
is a front view for the saddle-stitching unit in a stitching position in
FIG. 7
;
FIG. 16
is illustrating a stopper operation of the sheet processing apparatus in
FIG. 1
;
FIG. 17
is showing a relationship between a sheet bundle position and a stopper that is returned to a limiting position;
FIG. 18
is a perspective view of a preguide disposed in a transport guide;
FIGS.
19
(
a
) through
19
(
c
) show a retracting operation of the preguide in
FIG. 18
when the saddle-stitching unit moves; and
FIG. 20
is showing a sheet bundle folding operation of a folding unit disposed in the sheet processing apparatus in FIG.
1
.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Hereunder, embodiments of the invention will be explained with reference to the accompanied drawings.
FIG. 1
shows a structure of a copier as an example of an image forming apparatus with a sheet processing apparatus according to an embodiment of the present invention.
In the drawing, the main body
1
of the copier
20
comprises a platen glass
906
as a table for placing an original document, a light source
907
, a lens system
908
, a sheet feeder
909
, and an image forming section
902
. The main body
1
is provided with an automated document feeder
940
for automatically feeding an original document “D” to the platen glass
906
. Additionally, a sheet processing apparatus
2
is mounted on the main body
1
.
The sheet feeder
909
has cassettes
910
and
911
attached to the main body
1
for storing sheets of copy paper “S” and a deck
913
disposed on a pedestal
912
. The image forming section (image forming means)
902
has a cylindrical photosensitive drum
914
. Around the photosensitive drum
914
, provided in the image forming section
902
are a developer
915
, a separation charger
917
, a cleaner
918
, and a primary charger
919
. At downstream of the image forming section
902
, there are a feeding apparatus
920
, a fixing device
904
, and a pair of discharge rollers
1
a
and
1
b.
Operations of the mechanisms inside the main body
1
of the copier
20
will be explained next. When a paper feed signal is sent from a control unit
921
disposed in the main body
1
, the sheet “S” is discharged from the cassettes
910
and
911
, or the deck
913
. The light source
907
irradiates light to an original document “D” placed on the platen glass
906
. The light is reflected by the document D and passed through the lens system
908
to a photosensitive drum
914
.
The photosensitive drum
914
, pre-charged by a primary charger
919
, creates an electrostatic image thereon upon irradiation of the light. The developer
915
develops the electrostatic image to form a toner image. A resist roller
901
eliminates skew of the sheet of copy paper “S” fed from the sheet feeder
909
, and then adjusts a feeding timing to an image forming section
902
.
In the image forming section
902
, the toner image on the photosensitive drum
914
is transferred to the sheet of copy paper “S”. The sheet of copy paper “S” with the toner image is then charged to an opposite polarity to the transfer electrode
916
by the separating charger
917
to be separated from the photosensitive drum
914
.
The feeding apparatus
920
transports the sheet of copy paper “S” to the fixing unit
904
. The fixing unit
904
permanently fixes the image on the sheet of copy paper “S”. After fixing the image, the sheet of copy paper “S” is discharged to the sheet processing apparatus
2
from the main body
1
by a pair of the discharged rollers
1
a
and
1
b.
FIG. 2
is a side cross-section view of the sheet processing apparatus
2
. The sheet processing apparatus
2
is provided with a pair of feed guides
3
, a sheet-detecting sensor
4
, a processing tray
8
, a saddle-stitching unit
30
, and a folding unit
50
. A pair of the feed guides
3
receives a sheet discharged from a pair of the discharge rollers
1
a
and
1
b
, and guides the sheet into the sheet processing apparatus
2
. The sheet-detecting sensor
4
detects the sheet transporting in a pair of the feed guides
3
.
The sheet-detecting sensor
4
determines a timing to align and whether or not the sheet is jammed inside of the feed guide
3
. A pair of the discharge rollers
6
supports the sheet in the feed guide
3
sandwiched therebetween.
The processing tray
8
receives and stacks sheets discharged by a pair of the discharge rollers
6
. A pair of aligning plates
9
is disposed on the processing tray
8
to guide and align both edges of the sheet in a width direction perpendicular to the sheet bundle transport direction.
Each of the aligning plates
9
, as shown in
FIG. 3
, is attached to a side edge of the processing tray
8
in a width direction perpendicular to the sheet bundle transport direction. Each of the aligning plates
9
has a rack
16
that engages a pinion
15
disposed on a shaft of one of aligning motors
14
comprising a stepping motor disposed below the processing tray
8
. The aligning plates
9
move by an appropriate distance in the sheet transport direction when the aligning motors
14
at a front side and a backside rotate.
Depending on a type of copier that the sheet processing apparatus is attached to, whether discharged sheets are aligned based on a center or edges, the embodiment of the invention can discharge sheets aligned at either a center of the sheets or edges.
In
FIG. 2
, the feed guide
7
guides a sheet discharged from a pair of the discharge rollers
6
into the processing tray
8
. A paddle
17
is disposed below the feed guide
7
. The paddle
17
, which is made of a semicircular elastic rubber to secure grip, rotates around a center of a shaft
17
a
and contact an upper surface of a sheet.
The paddle
17
is also integrated with a fin
17
b
extending radially from a center of the shaft
17
a
and a paddle surface
17
c
. The paddle
17
deforms easily as sheets are stacked in the processing tray
8
to apply adequate force to the sheets so that the sheets can be transported properly.
The processing tray
8
has a first pulley
10
disposed on a first pulley shaft
10
a
and a second pulley
11
disposed a second pulley shaft
11
a
. A feed belt
12
is provided between the first pulley
10
and the second pulley
11
. A pressing pawl
13
is disposed on the circumference of the feed belt
12
.
The first pulley shaft
10
a
has a lower bundle feed roller
18
disposed thereon with the same axle. An upper feed roller
19
is provided above the lower bundle feed roller
18
, and moves between one position (shown in a dotted line) where the upper feed roller
19
abuts the lower bundle feed roller
18
and another position (shown in a solid line) separated from the lower bundle feed roller
18
.
A stopper
21
shown in
FIG. 2
has a single stopper plate
421
extended in a width direction of the sheet as shown in
FIG. 4. A
pair of the discharge rollers
6
discharges a sheet, then the sheet drops by its own weight into the processing tray
8
. The stopper plate
421
receives an edge of the sheet pushed by a rotation of the paddle
17
. A moving arm
23
shown in
FIG. 2
moves the stopper
21
.
One edge of the stopper
21
, as shown in
FIG. 2
, contacts a first pulley shaft
10
a
, and the stopper
21
always protrudes by a spring (not shown) to limit an edge of a sheet. Although, in
FIG. 4
, the stopper
21
is formed of a single plate, alternatively, as shown in
FIG. 5
, the stopper
21
may be formed of a plurality of stopper plates
221
disposed in the width direction of a sheet.
The saddle-stitching unit
30
has a staple-driving head unit
31
having a staple cartridge (not shown) and an anvil unit
32
for bending the staple driven out of the staple-driving head unit
31
. The staple-driving head unit
31
and the anvil unit
32
are disposed below and above a sheet bundle feed path
25
respectively and face to each other. The saddle-stitching unit
30
is constructed as a unit as shown by the dotted lines, and can be pulled out from the sheet processing apparatus
2
.
The staple-driving head unit
31
and the anvil unit
32
can move on the sheet bundle feed path
25
disposed between the staple-driving head unit
31
and the anvil unit
32
in a direction perpendicular to a sheet transport direction (to right in FIG.
2
). The direction is also along a surface of a sheet bundle facing the staple-driving head unit
31
and the anvil unit
32
.
Guide rods
33
and
34
guide the staple-driving head unit
31
and the anvil unit
32
, respectively, to move in the width direction thereof. Screw shafts
35
and
36
shift the staple-driving head unit
31
and the anvil unit
32
. A head drive shaft
38
drives the staple-driving head unit
32
to drive staples, and an anvil drive shaft
37
drives the anvil unit
31
to bend the staples, respectively. The saddle-stitching unit
30
will be described in detail later.
A head housing
224
, as shown in
FIG. 6
, is provided in the staple-driving head unit
31
, and has a staple blade (not shown) that drives the staples. The head housing
224
is attached to a guide base block
208
that supports the head housing
224
and moves in a width direction.
The guide base block
208
has a guide rod
34
inserted therein. The guide rod
34
guides the staple-driving head unit
31
(head housing
224
) to slide.
An attachment block
207
is provided on a side of the head housing
224
. The attachment block
207
is equipped with transmission gears
230
a
and
230
b
and an arm
229
for driving the staple blade in the head housing
224
by a force of the head drive shaft
38
.
A pin
232
is disposed on the transmission gear
230
b
. The pin
232
moves along a cam face
231
of the arm
229
. When the pin
232
moves, a recess portion at a tip of the arm
229
transports a pin
297
attached to a staple blade inside the head housing
224
along a slit
227
, thereby driving the staple blade to drive the staples.
In the embodiment, as sown in
FIG. 7
, the attachment block
207
can be detached from the head housing
224
(and the guide base block
208
) in a direction shown by arrows A and B. In a usual state, a positioning pin
299
of the head housing
224
engages a recess
207
a
of the attachment block
207
for positioning and fixed with a screw (not shown).
The guide base block
208
and the attachment block
207
have the positioning sensors
280
a
and
280
b
placed thereon respectively. These positioning sensors
280
a
and
280
b
which are detection means can detect whether the attachment block
207
is attached to the guide base block
208
and the head housing
224
or not and detect whether the attachment block
207
is attached at a correct position or not.
Such an arrangement allows only the attachment block
207
to be removed upon clogging of the staple or similar troubles, thereby increasing maintenance efficiency. The arrangement also allows the head housing
224
having the staple driving staple blade to remain in the apparatus together with the guide base block
208
. This does not deviate a precise relative position of the staple blade from an anvil body
241
(
FIG. 6
) even with the action of attachment and detachment upon maintenance, thereby preventing the staple from stitching error in operation after maintenance and assuring a secure saddle stitching.
Further, detection results of the positioning sensors
280
a
and
280
b
are input to the control block
149
shown in FIG.
8
. The control block
149
inhibits the staple driving head unit
31
and the anvil unit
32
from saddle stitching according to the detection results of the positioning sensors
280
a
and
280
b
if the attachment block
280
is not attached at all or has been attached in a position that is incomplete. Such an operation can prevent staple stitching error if a staple is clogged or not driven actually.
As for the saddle stitching inhibit control according to the detection results of the positioning sensors
280
a
and
280
b
when the attachment block
207
is mounted and removed as in
FIG. 7
, it may be made possible by such a construction type that the head
224
a
having the staple blade is integrated with the attachment block
207
a
as shown in FIG.
9
. For that construction, the detection results are obtained by a positioning sensor
281
a
disposed on a guide base block
208
a
and a positioning sensor
281
b
disposed on the attachment block
207
a.
As shown in the Figure, it also may be made possible by such an alternative construction that an anvil unit
323
is made of a guide base block
308
and a detachable attachment block
307
. For that construction, the detection results are obtained by a positioning sensor
282
a
disposed on the guide base block
308
and a positioning sensor
282
b
disposed on the attachment block
307
. That construction is the same as in FIG.
6
.
Furthermore, according to this embodiment, it is controlled to prohibit the saddle stitching based on the positioning detection detected by the control block
149
on the sheet post-processing apparatus when the attachment block
207
is mounted and dismounted. However, it may also be made in an alternative way by using an additional control means formed in the saddle stitching unit
30
itself. Still a further alternative method would be to have the control unit
921
formed in the main body
1
.
In addition,
FIG. 10
illustrates that the saddle stitching unit
30
has a gap detecting sensor
350
that can detect a space between the staple driving head unit
31
and the anvil unit
32
. Further, the drive force of the drive shaft
38
is transmitted via a timing belt
45
and via a staple/folding motor
170
A located on the anvil drive shaft
37
in the anvil unit
32
to a gear
175
.
With the gear
175
rotated, the cam
173
located on the rotating shaft
180
of the rotating shaft
175
on the gear
175
is pressed to a fixed frame
111
on the anvil unit
32
. As a result, a movable frame
140
on the anvil unit
32
supported via a collar
37
on the anvil drive shaft
37
to swing freely, as shown in
FIG. 11
, resists against the urging force of the coiled spring
157
to separate from the fixed frame
111
toward the staple driving head unit
31
.
The drive force of the head drive shaft
38
is transmitted to the gear
230
via the gear
38
A located on the head drive shaft
38
in synchronization with the drive force of the head drive shaft
38
that moves the movable frame
140
of the anvil unit
32
via the timing belt
45
.
The gear
230
, as shown in
FIG. 10
, has a cylindrical cam
232
having a notch
235
formed thereon. A detecting lever
366
having an engaging portion
360
and a detecting end
362
provided thereon is disposed to swing freely with a center of the shaft
363
being pressed toward the cam
232
by a spring
364
.
If the gear
230
is located at a position at which the gap between the staple driving head unit
31
and the movable frame
140
of the anvil unit
32
is fully opened, as shown in
FIG. 10
, the detecting lever
366
swings so that the engaging portion
360
can be put into the cutout
235
of the cylindrical cam
232
by the spring
364
.
With the engaging portion
360
put into the cutout
235
of the cam
232
, a detecting tip
365
of the detecting end
362
of the detecting lever
366
is moved to a position at which the detecting tip
365
is detected by the gap detecting sensor
350
. As a result, the gap detecting sensor
350
detects the detecting tip of the detecting lever
366
.
A signal from the gap detecting sensor
350
, as shown in
FIG. 9
, is input to the control block
149
. With the detection of the detecting tip
365
by the gap detecting sensor
350
, it is decided that the space between the staple driving head unit
31
and the movable frame
140
of the anvil unit
32
is fully opened as shown in FIG.
10
.
On the other hand, if the drive force of the head drive shaft
38
moves the movable frame
140
on the anvil unit
32
via the timing belt
45
, as shown in
FIG. 11
, the gear
364
is rotated via the gear
38
A located on the head drive shaft
38
in synchronization with the movement of the movable frame
140
. The rotation force resists the urging force of the spring
364
to push the engaging portion
360
of the detecting lever
366
from the notch
235
to press to the engaging surface of the circular cam
232
. The engaging portion
360
has a slant surface formed at the tip
360
thereof so that the engaging portion
361
can be pressed up to the engaging surface on the circular cam
232
.
Thus, the detecting tip
365
of the detecting end
362
can not be detected by the gap detecting sensor
350
while the engaging portion
360
of the detecting lever detecting lever
366
is pressed to the engaging surface of the circular cam
232
. As the gap detecting sensor
350
does not detect the detecting tip
365
, the control block
149
decides that the space between the staple driving head unit
31
and the movable frame
140
of the anvil unit
32
is out of a full open status as shown in FIG.
10
.
It is described so far that the control block
149
decides with the signal from the gap detecting sensor
350
whether or not the space between the staple driving head unit
31
and the movable frame
140
on the anvil unit
32
is fully open. Alternatively, a detection range of the gap detecting sensor
350
can be made wider to detect that the space between the staple driving head unit
31
and the movable frame
140
on the anvil unit
32
is made narrow from the full open state to a desired range.
The both units
31
and
32
must be usually moved in the width direction of the sheet bundle if saddle stitching is made at a plurality of positions in the width direction of the sheet bundle or if the staple driving head unit
31
and the anvil unit
32
are moved to a staple replacement position to replace the staples. For the saddle stitching unit
30
in this embodiment, however, the control block
149
inhibits the both units
31
and
32
from moving toward the width direction of the sheet bundle in the condition that the gap detecting sensor
350
detects that the both units
31
and
32
have a space therebetween narrower than a predetermined space (other than the full open status as in FIG.
10
).
If the both units
31
and
32
are permitted to move in the width direction of the sheet bundle in the narrow space state, the sheet bundle positioned for saddle stitching at a loading portion between the both units
31
and
32
may contact the staple driving head unit
31
or the anvil unit
32
in a particular case, such as the sheet bundle is floated up by curling or if the sheet bundle is bulky due to too many number of sheets or too thick sheet bundle.
Upon contact with the sheet bundle, the posture of the sheet bundle that has been aligned once deforms. As a result, the sheet bundle is stapled in the deformation state. Therefore, in this embodiment, the posture of the sheet bundle could not be deformed by any contact if the space is detected to exceed the predetermined distance, that is, in the status shown in
FIG. 10
, the control block
149
then permits the both units
31
and
32
to move in the width direction of the sheet bundle.
However, as will be explained later, there could be a case that a sheet presence detection sensor (not shown) detects that the sheet bundle is not present in the space between the both units
31
and
32
. The case occurs, as an example, if the sheet bundle does not reach the space between the both units
31
and
32
in the status that a preguide
370
for guiding the sheet bundle to a feed guide
39
is moved to a predetermined position and stands by, the preguide
370
being a supplement guide member for directing the sheet bundle toward the feed guide
39
which is a guide member for guiding the sheet bundle to the stitching position. This allows the staple driving head unit
31
and the anvil unit
32
to return to a home staple position that will be explained later.
The embodiment makes the above-described movement inhibit to control in the width direction of the sheet bundle by way of detecting the space between the both units
31
and
32
of the saddle stitching unit
30
. The way of control can be applied to any type of a mechanism that a stapler having a head and an anvil mechanically combined together other than the saddle stitching can be moved along an edge of the sheet bundle to bind the edge at a plurality of positions. If the space between the head and the anvil is detected to be too narrow, the stapler may be inhibited from moving along the edge of the sheet bundle.
In place of the control block
149
on the sheet post-processing apparatus
2
, alternatively, control means may be established in the saddle stitching unit
30
itself so that the control means can control to inhibit the both units
31
and
32
from moving in the width direction of the sheet bundle according to the gap detection between the both units
31
and
32
. Still another alternative is that the control unit
921
of the main body
1
may be used to make the control for the image forming system.
The embodiment explained above has the anvil unit
32
moved toward the staple driving head unit
31
thereby changing the gap. Alternatively, the staple driving head unit
31
may be moved toward the anvil unit
32
. Still a further alternative could be that both the units be moved toward each other.
It is alternatively possible to form a plurality of gap detection sensors in a structure to automatically set to a predetermined space by selecting a gap detection sensor to be used by control means according to conditions such as the number of sheets, the thickness of the paper of the sheet itself or the humidity or other conditions. The fixed carrying guide
39
guides the sheet stack carried inside the saddle stitching unit
30
.
The folding unit
50
for the sheet bundle, on the other hand, is the unit indicated by chain double-dashed line in FIG.
2
and can be drawn out of the sheet post-processing apparatus
2
as in the saddle stitching unit
30
. The folding unit
50
has a bundle feed guide
53
, upper bundle feed roller
51
, a lower bundle feed roller
52
, a bundle detecting sensor
54
for detecting a leading edge of the sheet bundle, an abutting plate
55
which is the pressing means, the paired folding rollers
57
a
and
57
b
which are the paired rotating bodies, and leading guide
56
provided therein.
A stack feed guide
53
guides the sheet bundle nipped and fed between the upper feed roller
19
and the lower bundle feed roller
18
located at the inlet of the saddle stitching unit
30
. The upper stack feed roller
51
is located at the inlet of the folding unit
50
. The lower bundle feed roller
52
is arranged to face the upper bundle feed roller
51
.
The upper bundle feed roller
51
is moved between a position (solid line) at which the upper bundle feed roller
51
is pressed to the lower bundle feed roller
52
and a separate position (dotted line). The upper bundle feed roller
51
is moved from the position separated from the lower bundle feed roller
52
to the contact position with the lower bundle feed roller
52
to nip and feed the sheet bundle together with the lower bundle feed roller
52
when the leading edge of the sheet bundle passes between the upper bundle feed roller
51
and the lower bundle feed roller
52
by the upper feed roller
19
and the lower feed roller
18
positioned at the inlet on the saddle stitching unit
30
.
A stack detecting sensor
54
for detecting the leading edge of the sheet bundle presses the upper stack feed roller
51
against the lower bundle feed roller
52
when detecting the leading edge of the sheet bundle. The stack detecting sensor
54
is also used to set and control the folding position in the feed direction of the sheet bundle. The paired folding rollers
57
a
and
57
b
are cylindrical rollers having flat parts extending in a width direction thereof. Both the rollers are urged in the directions to press each other when rotated.
The abutting plate
55
is made of a stainless steel plate of around 0.25 mm thick at an edge thereof. The abutting plate
55
is positioned right above the paired folding rollers
57
a
and
57
b
, and a leading edge thereof can be moved close to the nips of the paired folding rollers
57
a
and
57
b.
Around the upper portion of the paired folding rollers
57
a
and
57
b
, there are formed ark-like backup guides
59
a
and
59
b
to guide and feed the sheet bundle together with the stack feed guide
53
. The backup guides
59
a
and
59
b
are interconnected to move with the abutting plate
55
moving up and down to make an opening around the sheet bundle for the paired folding rollers
57
a
and
57
b
when the leading edge of the abutting plate
55
moves close to the nips of the paired folding rollers
57
a
and
57
b.
The leading guide
56
guides downward the sheet bundle nipped and fed by the upper stack feed roller
51
and the lower bundle feed roller
52
until the leading edge (the downstream edge) of the sheet bundle sags downward at a sheet bundle path
58
. In the stack delivery rollers
60
a
and
60
b
, the roller
60
a
is a drive roller, and the roller
60
b
is a driven roller.
A sheet bundle stacking tray
80
for the folded sheet bundles, as shown in the Figure, can stack sheet bundles that have been folded by the paired folding rollers
57
a
and
57
b
and discharged out by the paired bundle discharge rollers
60
a
and
60
b
. The sheet bundle discharged inside the sheet bundle stacking tray
80
is pressed by the folded sheet holder
81
urged downward by a spring or its own weight.
In turn, the following describes the construction of the processing tray
8
and the saddle stitching unit
30
of the sheet processing apparatus
2
in detail.
First, the processing tray
8
is described below. The processing tray
8
, as shown in
FIG. 3
, has a first pulley
10
and a second pulley
11
disposed virtually at a center thereof. The first pulley
10
and the second pulley
11
have a transfer belt
12
trained therebetween. On the first pulley shaft
10
a
, lower bundle feed rollers
18
are formed in two locations on each side of the sheet and substantially at the center of the sheet in the width direction thereof, the lower bundle feed rollers
18
being tire-like hollow rollers.
The first pulleys
10
are driven to rotate by the counterclockwise rotation of the first pulley shaft
10
a
in
FIG. 2
with a one-way clutch
75
interposed between the first pulleys
10
and the first pulley shaft
10
a
, and made for free driving to stop by clockwise rotation of the first pulley shaft
10
a
. The first pulley shaft
10
a
is interconnected via the pulley
73
fixed to the first pulley shaft
10
a
, the timing belt
74
, and gear pulleys
72
and
71
to the motor shaft
70
a
on the stepping motor
70
which serves as a source for the feed drive.
Therefore, the lower bundle feed roller
18
fixed to the first pulley shaft
10
a
is driven to rotate when the stepping motor
70
rotates to move the sheet on the processing tray
8
toward the staples in
FIG. 2
(in the direction of the arrow B in FIGS.
2
and
3
). The feed belt
12
, however, is stopped because no drive force is transmitted thereto because of the one-way clutch
75
. If the stepping motor
70
rotates to move the sheet toward the sheet elevator tray
90
, the lower bundle feed roller
18
and the feed belt
12
rotate toward the sheet elevator tray
90
(in direction of arrow A in FIGS.
2
and
3
).
The transfer belt
12
, as shown in
FIG. 12
, has a pushing pawl
13
disposed thereon. The processing tray
8
has a pushing pawl sensor
76
and a pushing pawl detecting arm
77
disposed thereunder to determine a home position thereof for the pushing pawl
13
. In this embodiment, the home position (HP) is determined at the position where the pushing pawl sensor
76
is turned from OFF to ON as the pushing pawl detecting arm
77
is pressed by the pushing pawl
13
moved together with the feed belt
12
.
In the Figure, let P denote a nip for the lower bundle feed roller
18
and the upper feed roller
19
, L
1
a length from the nip P to the stopper
21
, and L
2
a length from the nip P to the pushing pawl
13
along the feed belt
12
. L
1
and L
2
are set as L
1
<L
2
.
In turn, the following describes the sheet feed operation of the processing tray
8
explained above in construction. To feed the sheet bundle to the elevator tray
90
, first, a cam or the like (not shown) moves the upper feed roller
19
below the lower feed roller
19
to nip the sheet bundle together with the lower feed roller
19
. Second, the stepping motor
70
(
FIG. 3
) is rotated to rotate the first pulley shaft
10
a
counterclockwise. The lower feed roller
19
then is rotated to move the sheet bundle toward the elevator tray
90
in the arrow A direction.
Note that also that the upper feed roller
19
is rotated by the stepping motor
70
. Therefore, the sheet bundle is moved in the direction of the arrow A from the position of the stopper
21
inside the saddle stitching unit
30
, by the rotation of the lower bundle feed roller
18
and the upper feed roller
19
. When the sheet bundle passes the nip position P, the pushing pawl
13
hits with rotation of the feed belt
12
. With the pushing pawl
13
, the sheet bundle is fed to the elevator tray
13
while being pressed in the direction of the arrow A.
Because of L
1
<L
2
in the length relationship mentioned above, the pushing pawl
13
presses the bottom of the sheet bundle upward (from the right side in FIG.
12
), thereby always pressing the edge of the sheet bundle in an upright status. This does not cause excess stress in the transferring of the sheet bundle.
To feed the sheet bundle toward the saddle stitching unit
30
for saddle stitching, on the other hand, the pushing pawl
13
move counterclockwise from the HP position (
FIG. 12
) before receiving the sheet bundle moved from the stopper
21
by the paired rollers
18
and
19
synchronized therewith to feed the sheet bundle and push it out.
However, if the sheets fed into the processing tray
8
are not saddle-stitched by the saddle stitching unit
30
, the sheet bundle does not need to move to feed the sheet bundle to the stopper
21
position. The stepping motor
70
is driven in advance to move the pushing pawl
13
from the HP position in
FIG. 12
to a movement idle position (Pre-HP position) by a predetermined distance α from the nipping position of the lower bundle feed roller
18
and the upper feed roller
19
in a direction toward the elevator tray
90
.
The distance (L
2
+α) from the HP position to the Pre-HP position can be set by changing a step number count of the stepping motor
70
. If the present sheet processing apparatus
2
needs no saddle stitching for sheets, therefore, the sheets may not be transferred to the stopper
21
, but the pushing pawl
13
can be moved to the Pre-HP position in advance to stack the sheets on the elevation tray
90
before pushing the sheet stack out. This means that the sheet post-processing apparatus
2
is available for a high-speed duplicating machine.
Note that if the Pre-HP position of the pushing pawl
13
is a position where the feed guide
7
and the top of the pushing pawl
13
overlap each other, as shown in the Figure, the sheets fed one by one can be securely stacked at the Pre-HP position where the pushing pawl
13
exists. Such an arrangement allows the pushing pawl
13
to deliver the sheet bundle to the elevator tray
90
quickly.
In turn, the following describes the saddle stitching unit
30
. The saddle stitching unit
30
, as shown in
FIG. 13
, has right and left unit frames
40
and
41
, guide rods
33
and
34
, screw shafts
35
and
36
, and drive shafts
37
and
38
situated between the frames
40
and
41
, the anvil unit
32
thereabout and the staple driving head unit
31
thereunder.
The screw shaft
36
is engaged with the staple driving head unit
31
. The staple driving head unit
31
is moved in the horizontal direction in the Figure by rotation of the screw shaft
36
. The anvil unit
32
also is arranged similarly.
The screw shaft
36
is connected with the stapler slide motor
42
, which is the moving means, via the gear
36
A outside the unit frame
41
. Drive force of the stapler slide motor
42
is transmitted also to the anvil unit
32
by a timing belt
43
. This allows the staple driving head unit
31
and the anvil unit
32
to move in a direction (horizontal direction in
FIG. 13
) without deviation of vertical positions thereof.
The stapler slide motor
42
, therefore, can be driven to control the staple driving head unit
31
and the anvil unit
32
to move to a desired position depending on the width of the sheet, thereby allowing the staples to be driven at desired positions.
Top guides
46
a
,
46
b
,
46
c
, and
46
d
, which are float preventing guide members, are movably supported on the guide rod
33
and the anvil drive shaft
37
above the sheet bundle feed path
25
(
FIG. 2
) in an area surrounded by the anvil unit
32
and the right and left unit frames
40
and
41
as shown in
FIG. 14. A
roller
381
and the preguide
370
are disposed on the head-unit
31
.
Compression springs
47
a
,
47
b
,
47
c
,
47
d
,
47
e
, and
47
f
of an elastic material are interposed between the unit frame
41
and the upper guide
46
a
, between the upper guide
46
a
and the upper guide
46
b
, between the upper guide
46
b
and the anvil unit
32
, between the anvil unit
32
and the upper guide
46
c
, between the upper guide
46
c
and the upper guide
46
d
, and between the upper guide
46
d
and the unit frame
41
, respectively. The top guides
46
a
,
46
b
,
46
c
, and
46
d
move the upper guide rod
33
and the anvil drive shaft
37
in coordination with the movement of the anvil unit
32
.
As an example, if the sheet bundle is saddle stitched on a right side thereof, as shown in
FIG. 15
, the staple driving head unit
31
and the anvil unit
32
move to desired stitching positions on the right side from the position shown in
FIG. 14
while keeping a relative positional relationship therebetween. Along with the movement, the compression springs
47
d
,
47
e
, and
47
f
on the right side are compressed by the anvil unit
32
in coordination with the movement of the anvil unit
32
. The top guides
46
c
and
46
d
are moved to the right side as pushed by the compression springs
47
d
and
47
e.
The compression springs
47
a
,
47
b
, and
47
c
placed to the left side of the anvil unit
32
, on the other hand, are extended in coordination with the movement of the anvil unit
32
. The top guides
46
a
and
46
b
also move to the right side to serve for guiding at desired positions depending on sheet stitching positions.
The drive forces for moving the head to drive the staples in the staple driving head unit
31
, to move the staples, and to bend the staples in the anvil unit
32
are provided through the coupling device
44
from the sheet processing apparatus
2
and are also transmitted to the anvil unit
32
through the timing belt
45
on the unit frame
40
.
FIG. 16
shows parts of a side of the saddle stitching unit
30
. The stopper
21
is connected with the moving arm
23
by the connecting pin
23
c
, the connecting lever
22
, and the connecting pin
21
a
. The stopper
21
is pivoted by the first pulley shaft
10
a.
The following describes the appearance and disappearance of the stopper
21
in the sheet bundle feed path
25
to set the staple driving positions on the edge of the sheet bundle with the staple driving head unit
31
moved in the width direction of the sheets, in reference to
FIGS. 13 and 16
.
Below the head unit
31
, as shown in
FIG. 13
, the stopper abutting protrusion
24
is disposed to engage the stopper
21
with the moving arm
23
. The movement of the head unit
21
causes the stopper abutting protrusion
24
to abut against the moving arm protrusion
23
b
, which in turn causes the moving arm
23
to rotate around the turning shaft
23
a
in the counter-clockwise direction moving to the position of the dotted lines, as can be seen in FIG.
16
. With the movement, the stopper
21
, therefore, can not prevent the staple driving head unit
31
and the anvil unit
32
from moving in the width direction of the sheet bundle.
In the above-mentioned operational construction that the movement of the staple driving head unit
31
makes the stopper engaging projection
24
engage the moving arm projection
23
b
, a plurality of stoppers
221
forming the stopper
21
as shown in
FIG. 5
, may be alternatively placed in position and can all be saved from the staple path and the feed path
25
.
In turn, the following describes the control operation of the sheet processing apparatus
2
with reference to
FIG. 8. A
control block
149
comprises a central processing unit (CPU), a ROM for storing control means in advance that the CPU executes, and RAM for storing the operational data of the CPU and control data received from the main body
1
of the copier
20
. The control block
149
has I/O devices formed therein.
A block for aligning the sheets has a front aligning HP sensor
151
and a rear aligning HP sensor
152
for setting a home position (HP) of the aligning plates
9
that can align both edges of the sheets in the processing tray
8
. The aligning plates
9
(
FIG. 3
) stand by at positions of the front aligning HP sensor
151
and the rear aligning HP sensor
152
until the first sheet is fed into the processing tray
8
.
A front aligning motor
14
is a pulse motor for moving the front aligning plate
9
, and a rear aligning motor
14
is a pulse motor for moving the rear aligning plate
9
. The aligning motors
14
move the respective aligning plates
9
to align the width of the sheet bundle according to the width thereof. The aligning plates
9
can freely deviate each sheet bundle in the width direction.
A circuit for the elevator tray comprises a paper sensor
93
for detecting a top surface of the sheets thereon, an elevation clock sensor
150
for detecting the number of rotations of an elevator tray motor
155
with an encoder, and an upper limit switch
153
and a lower limit switch
154
to limit an elevation range for the elevator tray
90
. Signals input from the paper sensor
93
and elevation clock sensor
150
and the upper limit switch
153
and the lower limit switch
154
control the elevator tray motor
155
to drive the elevator tray
90
.
A block (relative to the sheet detection) for detecting whether or not a sheet or sheet bundle is stacked on the elevator tray
90
and in the sheet bundle stacking tray
80
, is equipped with an elevator tray paper sensor
156
for detecting the presence on the elevator tray
90
and a sheet bundle stacking paper sensor
157
in the sheet bundle stacking tray
80
. Those sensors
156
and
157
are also used as sensors for issuing alarms to an operator if any sheet remains before the sheet post-processing apparatus
2
is started or if a sheet bundle is not removed after a predetermined time elapses.
The block relative to a door open-close detection for detecting the opening of a door of the sheet processing apparatus
2
and whether or not the main body
1
of the copier
20
is properly mounted on the sheet processing apparatus
2
has a front door sensor
158
and a joint switch
159
for detecting whether or not the main body
1
of the image forming apparatus
20
has the sheet processing apparatus
2
mounted correctly.
The block (relative to sheet feed and bundle feed) for the sheet feed operation and the sheet bundle feed operation with the stacked sheets comprises a sheet detecting sensor
4
for detecting on the feed guide
3
that a sheet is fed from the main body
1
of the copier
20
to the sheet post-processing apparatus
2
, a processing tray sheet detecting sensor
160
for detecting the presence of a sheet on the processing tray
8
, a center stitching position sensor
95
, a center stitching and folding position sensor
95
′ for detecting the leading edge of the sheet bundle in the feed direction to deduce the same position for folding the sheets as the staple driven position, a pushing pawl sensor
76
for detecting a home position of the pushing pawl
13
established on the feed belt
12
for transferring the sheet bundle on the processing tray
8
toward the elevator tray
90
, and an upper stack feed roller HP sensor
161
for detecting the home position at which the upper stack feed roller
51
at an inlet of the folding unit
50
is separated away from the lower bundle feed roller
52
. The circuit can control the feed motor
162
and the stepping motor
70
according to signals from the respective sensors.
The rotating force of the feed motor
162
is transmitted to the paired feed rollers
5
, the paired discharge rollers
6
, the upper stack feed roller
51
, the lower bundle feed roller
52
, and the paired stack discharge rollers
60
a
and
60
b
. The reverse rotation of the feed motor
162
turns the upper roller moving cam
68
to move the paired stack feed rollers
51
. The rotating force of the stepping motor
70
is transmitted to the lower bundle feed roller
18
and the upper feed roller
19
formed on the processing tray
8
and the first pulley
10
to circulate the feed belt
12
.
The block (relative to paddle) for controlling the paddle
17
comprises a paddle HP sensor
163
to detect the rotating position of the paddle
17
and an upper feed HP sensor
164
to detect the position where the upper feed roller
19
separates from the lower bundle feed roller
18
, thereby controlling the paddle motor
165
according to signals from the sensors
163
and
164
.
The block (relative to staple/folding) for controlling the staple/folding operation is comprised of a staple HP sensor
166
to detect that the staple driving head unit
31
and the anvil unit
32
in the saddle stitching unit
30
can drive staples, a staple sensor
167
to detect whether or not the staple driving head unit
31
has staples set therein, a staple slide HP sensor
168
to detect whether or not the sheet bundle is at a home position (
FIG. 13
) when start-moving in the sheet feed direction between the both units
31
and
32
, a staple/folding clock sensor
171
to detect the rotation direction of the staple/folding motor
170
that can switch the drive of the saddle stitching unit
30
and the folding unit
50
to normal or reverse, and a safety switch
172
for detecting that the saddle stitching unit
30
and the folding unit
50
are operable. The circuit having the sensors and switches mentioned above controls the stapler slide motor
42
and the staple/folding motor
170
.
The stapler slide motor
42
transmits the rotating force to the screw shaft
36
to move the staple driving head unit
31
and the anvil unit
32
in the width direction thereof. A gear
170
is arranged to drive the coupling device
44
(
FIG. 14
) for the saddle stitching unit
30
in one of the normal or reverse rotation direction or the coupling device
137
(
FIG. 6
) for the folding unit
50
in the other rotation direction.
Next, the following describes operations in the process modes of the sheet processing apparatus
2
. This embodiment of the sheet processing apparatus
2
provides the following basic modes.
Non-staple mode: A mode for stacking the sheets onto the elevator tray
90
without stitching;
Side staple mode: A mode for saddle stitching the sheets at one or a plurality of positions on an edge (side) thereof in the sheet feed direction before loading the sheets onto the elevation tray
90
;
Saddle staple mode: A mode for stitching the sheets at a plurality of positions on a half length of the sheets in the sheet feed direction and for folding and binding the sheets at the stitched positions before stacking the sheets onto the sheet bundle stacking tray
80
.
At first, non-staple mode is explained. With this mode of process selected, the control block
149
drives the stepping motor
70
for rotating the transfer belt
12
to move the pushing pawl
13
at the home position (HP in
FIG. 12
) to the pre-home position (Pre-HP in
FIG. 12
) that is a sheet loading reference position on the processing tray
8
before stopping.
At the same time, the control block
149
drives the carrying motor
162
to rotate the pair of carrying rollers
5
and the pair of delivery rollers
6
and waits for a sheet to be delivered from the delivery rollers
1
a
and
1
b
of the main body
1
of the duplicating machine
20
. After that, when the sheet is discharged, the paired feed rollers
5
and the paired discharge rollers
6
feed the sheet to the processing tray
8
. Then, when the sheet detecting sensor
4
detects the sheet, start timings of the aligning motors
14
for the aligning plates
9
and the paddle motor
165
for rotating the paddle
17
are measured.
The control block
149
drives the aligning motors
14
and the paddle motor
165
while the sheet is discharged and stacked onto the processing tray
8
. With the drive, the aligning plates
9
move in the width direction traversing the sheet feed direction to align the both edges of the sheet, and the paddle
17
is rotated to make one side of the edges of the sheets strike the pushing pawl
13
at the Pre-HP position to align the sheets. This operation is repeated whenever the sheet is discharged to the processing tray
8
.
After that, if a predetermined number of sheets is aligned to the pushing pawl
13
, the control block
149
stops the feed motor
162
and the paddle motor
165
from rotating, and also restarts the stepping motor
70
for driving the feed belt
12
. With this operation, the sheet bundle is moved to the elevator tray
90
(the arrow A direction in
FIG. 3
) before being loaded on the elevator tray
90
.
Along with the delivery of the sheet bundle, the control block
149
makes the elevator tray motor
155
move down to a certain distance in a downward direction of the elevator tray
90
once. Subsequently, it drives the elevator tray motor
155
upward until the paper sensor
93
detects the top sheet before stopping, and makes the elevator tray motor
155
idle until the following sheet bundle is loaded thereupon.
In turn, the side staple mode is described below. When the side staple mode is selected, the control block
149
drives the feed motor
162
to rotate the paired feed rollers
5
and the paired discharge rollers
6
to deliver a sheet from the main body
1
of the copier
20
to the processing tray
8
to stack. The control block
149
also drives the aligning motors
14
and the paddle motor
165
while the sheet is discharged and stacked. With this operation, the sheet is aligned on both edges in the width direction thereof by the aligning plates
9
, and the leading edge of the sheet is transferred to the stopper
21
to stop. This operation is repeated for a specified number of sheets.
In the state where the sheet bundle is restricted by the stopper
21
, the upper feed roller
19
is moved to the lower bundle feed roller
18
to make the upper feed roller
19
and the lower bundle feed roller
18
nip the sheet bundle. At that time, the staple driving head unit
31
and the anvil unit
32
are both positioned at the staple home position shown in FIG.
13
.
The staple home position is a position where one stitching is made on the left unit frame
41
side shown in
FIG. 13
, that is, on the back side of the duplicating machine
20
and the sheet post-processing apparatus
2
shown in FIG.
1
. Positioning the both units
31
and
32
for the staple home position is made by moving the both units
31
and
32
for a distance of a specific number of pulses from the HP sensor (not shown) disposed on the left unit frame
41
side shown in FIG.
13
.
If the one-position stitching is specified, for example, the control block
149
makes the staple/folding motor
170
to be driven to rotate in the staple moving direction to make the both units
31
and
32
proceed with stitching. To stitch the sheets at a plurality of positions on the edge thereof, the stapler slide motor
42
should be driven to move the both units
31
and
32
from the staple home position to a desired staple position before proceeding with stitching.
After the stitching process is finished, the lower feed roller
18
and the upper feed roller
19
are rotated, and the transfer belt
12
is moved toward the elevation tray
90
side (arrow A direction in
FIG. 3
) by the stepping motor
70
. This delivers the sheet bundle to the lower bundle feed roller
18
, the upper feed roller
19
, and pushing pawl
13
in this order before loading the sheet bundle onto the elevator tray
90
. The operation of the elevator tray
90
is the same as in the nonstaple mode described above, so that an explanation shall be omitted.
In turn, the saddle staple mode is described below. Because the stacking of the sheets discharged from the copier
1
onto the processing tray
8
is similar to that of the side staple mode of operation described above, a description shall be omitted.
After the sheets are aligned and loaded on the processing tray
8
, the upper carrying roller
19
is moved down to the lower carrying roller
18
side to make the upper carrying roller
19
and the lower carrying roller
18
nip the sheet stack. In turn, the stopper
21
is retracted away from the feed path
25
before the control block
149
drives the stapler slide motor
42
to transfer the sheet bundle in the arrow B direction in FIG.
3
.
The drive allows the stopper engaging projection
24
on the staple driving head unit
31
also to move as shown in
FIG. 13
to engage the moving arm
23
. This retracts the stopper
21
from an area where the staple driving head unit
31
and the anvil unit
32
move, as shown in FIG.
16
.
It should be noticed that the stopper
21
may be alternatively replaced by a single wide stopper plate
421
(
FIG. 4
) or a plurality of stopper plates
221
(
FIG. 5
) extending in the direction in which the staple driving head unit
31
moves along the guide rod
34
, the direction being a direction orthogonal to the direction in which the sheets are delivered from the duplicating machine
20
to the sheet post-processing apparatus
2
or a direction orthogonal to the direction in which the sheet bundle is fed in the sheet bundle feed path.
By the engagement of the stopper engaging projection
24
of the staple driving head unit
31
with the moving arm
23
, all the stopper plates are moved away from the moving area of the staple driving head unit
31
and the anvil unit
32
to make the sheet bundle feed path free.
In this embodiment, the stopper engaging projection
24
is disposed in the staple driving head unit
31
. Alternatively, the stopper engaging projection
24
can be placed in the anvil unit
32
SO as to retract the stopper away from the moving area of the staple driving head unit
31
and the anvil unit
32
along with movement of the anvil unit
32
to make the sheet bundle feed path free.
In such a construction, the staple driving head unit
31
and the anvil unit
32
move from the home staple position shown in
FIG. 13
along the guide rods
33
and
34
to open the sheet bundle feed path
25
free before stopping at the driving set positions in the width direction. The stopping positions of the both units
31
and
32
, however, can be specifically controlled to change depending on the difference of the alignment reference by the aligning plate
9
and difference of the sheet size as will be described later.
Further, the control block
149
rotates the stepping motor
70
in a direction reverse to the non-staple and side staple modes in the process. This drive makes the sheet bundle feed in the direction reverse (the direction of the arrow B in
FIGS. 2 and 3
) to the elevator tray
90
. If, in the transfer, the stack detecting sensor
54
in the folding unit
50
detects a leading end of the sheet stack in the carrying direction (sheet size data), the upper carrying roller
19
and the lower carrying roller
18
carry and stop the sheet stack to a position at which the approximate middle position in the sheet carrying direction coincides with the stitching position according to the sheet length information in the carrying direction sent in advance.
It should be noticed that if the stepping motor
70
rotates in the reverse direction, the one-way clutch
75
interposed between the first pulley
10
and the first pulley shaft
10
a
for tightly stretching the transfer belt
12
prevents the rotating force of the stepping motor
70
from transmitting but keeps the transfer belt
12
and the pushing pawl
13
stopped at the home position.
Next, the control block
149
rotates the staple/folding motor
170
for driving the drive shaft
38
and the anvil drive shaft
37
to rotate in the directions for operation thereof to stitch. When there requires a plurality of stitchings at a plurality of positions, the stapler slide motor
42
is driven to rotate the screw shafts
35
and
36
to move to the specific positions in the width direction before stitching.
After saddle stitching the sheet bundle at a single position or a plurality of positions, the both units
31
and
32
are moved from the final stitching position to the home staple position shown in
FIG. 13
along the guide rods
33
and
34
. This disengages the stopper engaging projection
24
of the staple driving head unit
31
from the moving arm
23
. As a result, the stopper
21
(stopper plate
421
or
221
) returns to the moving area of the both units
31
and
32
, closes the feed path
25
, and prepares for the alignment of the leading edge of the next sheets.
Accordingly, in a stroke of the both units
31
and
32
moving from the staple home position to the staple position and returning again to the staple home position, the position for retracting the stopper
21
, the position for stitching process, and the position for returning the stopper in the sheet bundle feed path
25
are already set. In the stroke, there is also set the position for a preguide
370
(which will be described later) to guide the sheet bundle.
It should be noticed that timing when the both units
31
and
32
move from the position for stitching the final sheet bundle to the position for allowing the stopper
21
to return to the feed path
25
do not need to wait until the sheet bundle having the finished stitching is entirely delivered from the sheet post-processing apparatus
2
. If a trailing edge of the sheet bundle S in the feed direction has passed over the stopper
21
as shown in
FIG. 27
, for example, the stopper
21
can be moved to the position for returning into the feed path
25
.
Therefore, alternatively, the both units
31
and
32
may start to move at an instance when the both units
31
and
32
reach a position to which the stopper
21
is returned after the trailing edge of the sheet bundle has passed over the stopper
21
with reference to the size of the sheet, a sheet bundle feed speed, and other factors. Such a scheme can make it fast to make ready for accepting a next sheet stack.
The leading edge of the sheet bundle may be caught at an upstream edge of the feed guide disposed in a lower casing
30
A having the staple driving head unit
31
of the saddle stitching unit
30
shown in
FIG. 28
attached thereto when the sheet bundle passes over the stopper
21
moved to the retracted position to the stitching position. This causes the sheet bundle to be deformed in posture and the sheets to be stacked, resulting in incorrect saddle stitching.
To prevent such a failure, in the embodiment, the preguide
370
is provided at an upstream side of the feed guide. The preguide
370
guides the sheet bundle to the feed guide
39
without allowing the leading edge thereof to touch the upstream edge of the feed guide
39
when the sheet bundle is fed to the stitching position.
The preguide
370
, as shown in
FIG. 28
, is disposed to project higher than the feed guide
39
to prevent the leading edge of the sheet bundle from being caught by the upstream of the feed guide
39
. Also, the preguide
370
has a slope
370
a
provided for guiding the sheet bundle above the feed guide in the projection direction to prevent the leading edge of the sheet bundle from touching the upstream edge of the feed guide
39
after the preguide
370
abuts against the sheet bundle.
With a preguide
370
, the sheet bundles can be guided to the feed guide
39
without the leading edges thereof catching on an upstream side of the feed guide
39
. The sheet bundles led to the feed guide
39
can be firmly supported in the width direction by the feed guide
39
. The sheet bundles can be correctly saddle stitched by the staple-driving head unit
31
and the anvil unit
32
.
According to the preferred embodiment of the present invention, the preguide
370
is disposed to one side of the feed guide
39
in the upstream direction of sheet transport via the turning shaft
370
b
, as can be seen in FIGS.
19
(
a
) to (
c
). When the staple-driving unit
31
moves in a width direction of the sheets, the preguide
370
is pressed by the staple-driving unit
31
and rotates around the turning shaft
370
b
. As a result, the preguide
370
retracts to a position where it does not interfere a movement of the staple-driving unit
31
.
Also, the preguide
370
is urged by a spring (not shown) in the protruding direction to guide the sheet bundle above the feed guide
39
, so that the leading edge of the sheet bundle does not touch a upstream edge of the feed guide
39
. The preguide
370
protrudes above the feed guide
39
when not being pressed by the staple-driving unit
31
.
According to the preferred embodiment of the present invention, an inclined contact portion
370
c
is attached to the preguide
370
. The staple-driving unit
31
presses the inclined contact portion
370
c
when the staple-driving unit
31
moves in a sheet width direction, and the preguide
370
can smoothly move (rotate) to the retracted position.
Also, two pairs of rollers
381
are disposed on the cover
380
of the staple-driving unit
31
at a position facing the preguide
370
(see FIG.
18
). The rollers
381
touch the contact portion
370
c
to assist the retracting movement of the preguide
370
when the staple-driving head moves.
As can be seen in FIG.
19
(
a
), the staple-driving unit
31
moves in the direction of the arrow A. Then, when the staple-driving unit
31
presses against the contact portion
370
c
with the roller
381
, the preguide
370
rotates around the turning shaft
370
b
in the direction of the arrow B as can be seen in FIG.
19
(
b
), thereby being moved to the retract position, as can be seen in FIG.
19
(
c
).
Through the rotational movement of the preguide
370
to the retracted position by the staple-driving unit
31
, the staple-driving head
31
can be moved without being hindered by the preguide
370
, thereby securing a wide space for stitching of the staple-driving unit
31
. Also, the staple-driving unit can be moved to a side direction for easier access to replace staples.
In the embodiment, the preguide
370
is disposed to the feed guide
39
to move separately, but it is also acceptable to dispose the preguide
370
to the staple-driving head unit
31
so that the preguide
370
can move together with the staple-driving head unit
31
.
In the case that the preguide
370
is disposed to the staple-driving head unit
31
, when the sheet bundle aligned by the aligning plates
9
with reference to a center in the width direction is transported to the feed guide
39
, the preguide
370
moves to a center in the width direction along with the staple-driving unit
31
, or its proximity, for example, to a stitching position. This allows the sheet bundle to be balanced and guided to the feed guide
39
.
In case, the sheet bundle, which is aligned on the base of either side of the edges in the width direction by the aligning plate
9
, is transferred to the feed guide
39
, the center of the sheet changes depending of the sheet size. However, the control block
149
as control means can control the stapler slide motor
42
on the basis of at least one of the aligning reference and the sheet size data, so that the preguide
370
is moved to the center position in the width direction or to the position close thereto depending on size of the sheet together with the staple driving head unit
31
. With such a control, the sheet bundle can be guided into the feed guide
39
in good balance.
As the preguide
370
is disposed to the staple-driving unit
31
, the preguide
370
, moving together with the staple-driving unit
31
, touches the side plate
382
on the lower case
30
A (see
FIG. 18
) when the staple-driving unit
31
moves close to the side of the feed guide
39
to staple the sheet bundle, thereafter moving to the retracting position along the side plate
382
.
Since the preguide
370
moves to the retracting position, the staple-driving unit
31
is able to move freely without the hindrance of the preguide
370
. Note that by disposing the roller
381
to the side plate
382
on the lower case
30
A, as shown in the FIGS.
19
(
a
) to (
c
), the preguide
370
is able to move securely to the retracting position.
In the embodiment, the preguide
370
is disposed on the staple driving head unit
31
side viewed from the sheet bundle since a leading edge of the sheet bundle curled on the side of the staple driving head unit
31
arranged on a printing side of the sheets tends to be caught by the upstream edge of the feed guide
39
as curling occurs usually on the leading edge of the sheets.
The invention is not limited to the embodiment mentioned above, and alternatively the feed guide may be attached to the anvil unit
32
. If the feed guide may be attached to the anvil unit
32
, the preguide
370
may be placed on the side of the anvil unit
32
as viewed from the sheet bundle, for example, on an additional side cover (not shown) fixed to the anvil unit
32
.
It should be noted that the feed guide
39
has a cutout portion
390
that is slanted on the upstream edge thereof from the center portion toward the edge in the sheet feed direction as shown in FIG.
18
. With the slanted cutout portion
390
, the edges of the sheet bundle can be smoothly guided to a guide surface on the feed guide
39
.
When the sheet bundle has been fed to the stitching position, the leading edge of the sheet bundle in the feed direction already passes an area between the lower bundle feed roller
52
in the folding unit
50
and the upper stack feed roller
51
separated from the lower bundle feed roller
52
.
After the stitching is completed, the sheet bundle is fed to come to an approximate center in the feed direction, that is, to bring the stitched position to become the folding position. The staple/folding motor
170
then is driven in a reverse direction of the stitching process. The pair of folding rollers
57
a
and
57
b
is rotated in the directions of nipping the sheet bundle S, and the abutting plate
55
is moved down as shown in FIG.
22
. At the same time, the backup guides
59
a
and
59
b
move to free the paired folding rollers circumferences at the sheet bundle side.
After the abutting plate
55
has moved the rotating paired folding rollers
57
a
and
57
b
having the sheet bundle nipped therebetween, the sheet bundle S is rolled in between the paired folding rollers
57
a
and
57
b
. After that, while the abutting plate
55
moves in the direction separating from the sheet bundle, the sheet bundle is further folded by the paired folding rollers
57
a
and
57
b.
At this point, the bundle feed upper roller
51
, bundle feed lower roller
52
and the paired bundle feed rollers
60
a
and
60
b
are rotated in the direction to discharge the sheet bundle to the stack loading tray by the feed motor
162
. The paired folding rollers
57
a
and
57
b
, on the other hand, are stopped when the abutting plate
55
moves up and is detected by the abutting plate HP sensor (not shown).
The sheet bundle S nipped and fed by the paired stack discharge rollers
60
a
and
60
b
is discharged to and stacked on the sheet bundle stacking tray
80
. The folded sheet bundle is held down by the folded sheet holder
81
so that it does not open, thereby not preventing a subsequent folded sheet bundle from being fed in.
It should be noted that the upper stack feed roller
51
separates from the lower bundle feed roller
52
, moves up, and prepares to feed in the next sheet bundle when a period of time available for the paired stack discharge rollers
60
a
and
60
b
to deliver the sheet bundle has elapsed.
In the saddle stitch mode in the embodiment described above, the stitching process and the folding process are consecutive. It should be known that only the folding process can be performed without the stitching process. Furthermore, the folded sheet bundle device can stack thereon only the sheet bundles folded but not stitched.
As described in detail above, the supplement guide member is disposed on an upstream of the guide member guiding the sheet bundle to the stitching position in the sheet bundle transport direction. Such a feature is effective that when the sheet bundle is fed to the stitching position, the sheet bundle can be led to the guide member without the leading edge of the sheet bundle touching an upstream of the guide member in the sheet bundle transport direction. This assures of secure feed of the sheet bundle and correct stitching.
Furthermore, when the stitching unit moves, the supplement guide member is retracted to a position that does not interfere with the movement of the stitching unit. Along with the movement thereof, this configuration allows a wide area for the stitching unit to stitch, without hindrance by the supplement guide member. Also, this enables the stitching unit to be moved to a side direction where it is easier to access and to replace staples.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.
Claims
- 1. A sheet processing apparatus for processing a sheet bundle, comprising:a stitching unit including a head portion for driving staples into the sheet bundle, and an anvil portion for receiving and bending said staples driven by the head portion and facing said head portion; feeding means for feeding the sheet bundle to a stitching position between the head portion and the anvil portion in the stitching unit; transport means attached to the stitching unit for transporting the same to a position perpendicular to a sheet bundle feeding direction; a guide member disposed between the head portion and the anvil portion for guiding the sheet bundle to the stitching position; and a supplement guide member disposed at an upstream side of the guide member in the sheet bundle feeding direction, said supplement guide member being able to retract to a position that does not hinder movement of the stitching unit when the stitching unit moves, and guiding the sheet bundle to the guide member without a leading edge of the sheet bundle touching an upstream edge of the guide member in the sheet bundle feeding direction when the sheet bundle is fed to the stitching position.
- 2. A sheet processing apparatus for processing a sheet bundle according to claim 1, wherein said supplement guide member has an inclined contact portion abutting against the stitching unit so that the supplement guide member retracts when the stitching unit moves.
- 3. A sheet processing apparatus for processing a sheet bundle according to claim 2, wherein said stitching unit has a roller abutting against said contact portion.
- 4. A sheet processing apparatus for processing a sheet bundle according to claim 1, wherein said supplement guide member is disposed on the stitching unit so that when the stitching unit moves to a predetermined position, the supplement guide member retracts to a position that does not interfere with a movement of the stitching unit.
- 5. A sheet processing apparatus for processing a sheet bundle according to claim 1, further comprising:aligning means situated adjacent to the stitching unit for aligning a side of the sheet bundle perpendicular to the sheet bundle feeding direction; and control means connected to the transport means for controlling the same so that a position of the supplement guide member is changed based on at least one of an aligning reference of said aligning means and a sheet size.
- 6. An image forming apparatus comprising:an image forming unit; and a sheet processing apparatus attached to the image forming unit for processing a sheet bundle having sheets with images formed by the image forming unit, said sheet processing apparatus being formed according to claim 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-021663 |
Jan 2001 |
JP |
|
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