U.S. patent application number 12/699359 was filed with the patent office on 2010-08-05 for sheet carrying method for sheet finishing device.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Ken IGUCHI.
Application Number | 20100194020 12/699359 |
Document ID | / |
Family ID | 42397036 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100194020 |
Kind Code |
A1 |
IGUCHI; Ken |
August 5, 2010 |
SHEET CARRYING METHOD FOR SHEET FINISHING DEVICE
Abstract
A sheet finishing device includes: a housing unit which houses a
sheet discharged from an image forming apparatus; a carrying unit
which carries the sheet discharged from the image forming apparatus
in a direction of the housing unit; a standby unit which is
arranged on a carrying path of the carrying unit and temporarily
holds the sheet; a finishing unit which is arranged on the carrying
path of the carrying unit and performs finishing of the sheet; and
a control unit which, when a carrying error in the carrying unit is
a first error, controls the carrying unit to stop and responses the
first error to the image forming apparatus, and when the carrying
error is a second error, controls the carrying unit to continue
driving and responses the second error to the image forming
apparatus.
Inventors: |
IGUCHI; Ken; (Shizuoka,
JP) |
Correspondence
Address: |
PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
TOSHIBA TEC KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
42397036 |
Appl. No.: |
12/699359 |
Filed: |
February 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61150267 |
Feb 5, 2009 |
|
|
|
Current U.S.
Class: |
270/58.07 ;
270/58.01; 271/278 |
Current CPC
Class: |
B65H 39/10 20130101;
B65H 2511/414 20130101; B65H 2301/16 20130101; B65H 31/3081
20130101; B65H 2801/27 20130101; B65H 2513/512 20130101; B65H
2511/52 20130101; B65H 31/02 20130101; B65H 31/3018 20130101; B65H
2405/11151 20130101; B65H 2513/53 20130101; B65H 2301/4212
20130101; B65H 2301/4213 20130101; B65H 2511/414 20130101; B65H
2220/02 20130101; B65H 2511/52 20130101; B65H 2220/01 20130101;
B65H 2513/512 20130101; B65H 2220/02 20130101; B65H 2513/53
20130101; B65H 2220/01 20130101 |
Class at
Publication: |
270/58.07 ;
270/58.01; 271/278 |
International
Class: |
B65H 39/00 20060101
B65H039/00; B65H 29/00 20060101 B65H029/00 |
Claims
1. A sheet finishing device comprising: a housing unit which houses
a sheet discharged from an image forming apparatus; a carrying unit
which carries the sheet discharged from the image forming apparatus
in a direction of the housing unit; a standby unit which is
arranged on a carrying path of the carrying unit and temporarily
holds the sheet; a finishing unit which is arranged on the carrying
path of the carrying unit and performs finishing of the sheet; and
a control unit which, when a carrying error in the carrying unit is
a first error, controls the carrying unit to stop and responses the
first error to the image forming apparatus, and when the carrying
error is a second error, controls the carrying unit to continue
driving and responses the second error to the image forming
apparatus.
2. The device of claim 1, wherein the first error is a sheet jam in
which the sheet is jammed in the carrying path, and the second
error is an operation delay generated on the carrying path.
3. The device of claim 1, wherein when the carrying error is the
second error, the control unit requests a delay request to delay
image formation that is to be newly started, to the image forming
apparatus.
4. The device of claim 1, wherein when the carrying error is the
second error, the control unit requests a stop request to stop
image formation that is to be newly started, to the image forming
apparatus.
5. The device of claim 2, wherein when the carrying unit is
controlled to continue driving in the case where the operation
delay is an operation delay in the finishing unit, the carrying
unit continues carrying the sheet discharged from the image forming
apparatus up to the standby unit and stands by the sheet in the
standby unit.
6. The device of claim 5, wherein when the operation delay is an
operation delay in the finishing unit, the control unit requests a
delay request to delay image formation that is to be newly started,
to the image forming apparatus, and the carrying unit continues
carrying the sheet discharged from the image forming apparatus by
already started image formation up to the standby unit and stands
by the sheet in the standby unit.
7. The device of claim 6, wherein the finishing unit has a
supporting unit which is arranged between the standby unit and the
housing unit in the carrying path and supports the sheet that is
carried directly from the image forming apparatus or carried via
the standby unit, and an alignment unit which aligns the sheet on
the supporting unit, the carrying unit has a paper discharge unit
which discharges the sheet on the supporting unit to the housing
unit, and the carrying unit carries the sheet from the standby unit
to the supporting unit when paper discharge operation by the paper
discharge unit is completed.
8. The device of claim 7, wherein when the number of sheets
standing by in the standby unit exceeds a prescribed number of
sheets, an alignment operation by the alignment unit is
increased.
9. The device of claim 6, wherein the delay request delays the
image formation that is to be newly started until the finishing
unit completes a finishing operation, then resumes new image
formation to the image forming apparatus.
10. The device of claim 2, wherein when the carrying unit is
controlled to continue driving in the case where the operation
delay is an operation delay in the standby unit, the control unit
requests a stop request to stop image formation that is to be newly
started, to the image forming apparatus, and the carrying unit
carries the sheet discharged from the image forming apparatus by
already started image formation, directly to the housing unit.
11. A sheet carrying method for a sheet finishing device
comprising: carrying a sheet discharged from an image forming
apparatus in a first direction, with or without a finishing
operation; stopping the carrying of the sheet in the first
direction and notifying the image forming apparatus of the first
error when a carrying error is a first error; and continuing the
carrying of the sheet in the first direction and notifying the
image forming apparatus of the second error when the carrying error
is a second error.
12. The method of claim 11, wherein the first error is a sheet jam
in which the sheet is jammed while the sheet is carried in the
first direction, and the second error is an operation delay
generated at the time of carrying out the finishing operation of
the sheet.
13. The method of claim 11, wherein when the carrying error is the
second error, requesting a delay request to delay image formation
that is to be newly started to the image forming apparatus.
14. The method of claim 11, wherein when the carrying error is the
second error, requesting a stop request to stop image formation
that is to be newly started to the image forming apparatus.
15. The method of claim 12, wherein when an operation delay occurs
at the time of carrying out the finishing operation of the sheet,
when the carrying of the sheet in the first direction is continued,
continuing the carrying of the sheet discharged from the image
forming apparatus in the first direction to a standby unit and
standing by the sheet in the standby unit.
16. The method of claim 15, wherein when an operation delay occurs
at the time of carrying out the finishing operation of the sheet,
when the carrying of the sheet in the first direction is continued,
requesting a delay request to delay image formation that is to be
newly started to the image forming apparatus, and continuing the
carrying of the sheet in the first direction discharged from the
image forming apparatus by already started image formation to the
standby unit and standing by the sheet in the standby unit.
17. The method of claim 16, wherein when the operation delay is a
sheet discharge delay from a supporting unit downstream from the
standby unit, carrying the sheet from the standby unit to the
supporting unit when the discharge of the sheet from the paper
discharge unit is completed.
18. The method of claim 17, wherein when the number of sheets
standing by in the standby unit exceeds a prescribed number of
sheets, increasing an operation to align the sheet on the
supporting unit.
19. The method of claim 16, wherein the delay request delays the
image formation that is to be newly started until the finishing
operation of the sheet is completed, then resumes new image
formation to the image forming apparatus.
20. The method of claim 12, wherein when the operation delay is an
operation delay in the standby unit, requesting a stop request to
stop image formation that is to be newly started to the image
forming apparatus, and carrying the sheet discharged from the image
forming apparatus by already started image formation in the first
direction and housing directly in a housing unit.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from Provisional U.S. Application 61/150,267 filed on
February 5, the entire contents of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a sheet finishing device
which finishes a sheet having an image formed thereon by an image
forming apparatus such as a copier or MFP (multi-functional
peripheral).
BACKGROUND
[0003] There is a sheet finisher which performs finishing such as
stapling and bundle carrying of sheets discharged from an image
forming apparatus. In the sheet finisher, while a sheet is carried
to a finishing unit or a paper discharge tray, a timing error may
occur which is caused by a delay in carrying the sheet or a delay
in finishing due to the difference in paper quality among various
sheets and so on. In order to resume the sheet finisher and the
image forming apparatus that are stopped by the timing error, the
user must remove the sheet left in the sheet finisher or the image
forming apparatus even though the sheet is not damaged. Moreover,
it is difficult to remove the sheet left in the sheet finisher or
the image forming apparatus, and maintenance of these devices takes
time. What is more, the sheet that is not damaged in the first
place may be wasted.
[0004] Thus, there is demand for a sheet finisher in which, when a
timing error occurs while a sheet is being finished, the user's
operation to remove the sheet is reduced, maintenance performance
is thus improved, and no sheets are wasted.
SUMMARY
[0005] According to an aspect of the invention, a sheet finishing
device includes: a housing unit which houses a sheet discharged
from an image forming apparatus; a carrying unit which carries the
sheet discharged from the image forming apparatus in a direction of
the housing unit; a standby unit which is arranged on a carrying
path of the carrying unit and temporarily holds the sheet; a
finishing unit which is arranged on the carrying path of the
carrying unit and performs finishing of the sheet; and a control
unit which, when a carrying error in the carrying unit is a first
error, controls the carrying unit to stop and responses the first
error to the image forming apparatus, and when the carrying error
is a second error, controls the carrying unit to continue driving
and responses the second error to the image forming apparatus.
DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic view showing the configuration of a
sheet finisher connected to an MFP according to an embodiment;
[0007] FIG. 2 is a schematic view showing the configuration of the
sheet finisher according to the embodiment;
[0008] FIG. 3 is a schematic perspective view showing a part of
finisher unit according to the embodiment;
[0009] FIG. 4 is a schematic plan view showing standby trays
according to the embodiment;
[0010] FIG. 5A is a schematic block diagram showing the control
system of the sheet finisher according to the embodiment;
[0011] FIG. 5B is a schematic explanatory view showing a part of a
response format to be response to the MFP from a finisher control
circuit according to the embodiment;
[0012] FIG. 6 is a schematic explanatory view showing the
occurrence of a paper jam error according to the embodiment;
[0013] FIG. 7 is a schematic explanatory view showing the
occurrence of a timing error due to a delay in discharging a sheet
bundle according to the embodiment;
[0014] FIG. 8 is a schematic explanatory view showing the
occurrence of a timing error due to a delay in rotation of an
assist arm according to the embodiment;
[0015] FIG. 9 is a flowchart showing a process when a timing error
occurs, according to the embodiment;
[0016] FIG. 10 is a schematic explanatory view showing a sheet in
the MFP when a bundle discharge timing error occurs, according to
the embodiment;
[0017] FIG. 11 is a schematic explanatory view showing a sheet
buffered to a standby tray after a bundle discharge timing error
occurs, according to the embodiment; and
[0018] FIG. 12 is a schematic explanatory view showing the
continuation of carrying a next bundle according to the
embodiment.
DETAILED DESCRIPTION
[0019] An embodiment will be described hereinafter. FIG. 1 is a
schematic view showing the configuration of a multi-functional
peripheral (MFP) 10 as an image forming apparatus according to the
embodiment, and a finisher 20 as a sheet finishing device connected
to the MFP 10. The finisher 20 is connected to a lateral side of
the MFP 10 via a relay unit 60. In the MFP 10, a printer unit 11
forms an image on a sheet P and the sheet P is discharged from a
paper discharge roller pair 12 to the finisher 20 via the relay
unit 60. The MFP 10 has a scanner 8 and a control panel 14 having a
display panel 14a, in an upper part of the printer unit 11. The MFP
10 has a pickup roller 17 which takes out a sheet P from a paper
supply unit 16.
[0020] The finisher 20 has, for example, a stapler 56 which staples
sheets as a finishing unit, as shown in FIG. 2. The finisher 20 is
carries the sheet P, discharged from the paper discharge roller
pair 12 of the MFP 10 and relayed by the relay unit 60, to a first
tray 21 or a second tray 22 as a housing unit. The finisher 20 has
a first carrying mechanism 23 which carries the sheet discharged
from the paper discharge roller pair 12 in the direction of the
first tray 21, and a second carrying mechanism 24 which carries the
sheet P discharged from the paper discharge roller pair 12 in the
direction of the second tray 22, as a carrying unit.
[0021] The first carrying mechanism 23 has an entrance roller pair
26 and a first exit roller pair 27. The second carrying mechanism
24 has a first path 31 for carrying the sheet P in the direction of
the second tray 22 via the entrance roller pair 26, a second exit
roller pair 28, and a standby tray roller pair 30 on the exit side
of standby trays 32a and 32b. The second carrying mechanism 24 has
a second path 41 for carrying the sheet P in the direction of the
second tray 22 via the entrance roller pair 26, the second exit
roller pair 28, the standby trays 32a and 32b, and a processing
tray 50.
[0022] The finisher 20 has the processing tray 50 as a supporting
unit which constituting the finishing unit and supports the sheet P
at the time of finishing, and lateral alignment boards 51 and 52
which align the sheet P on the processing tray 50 in the lateral
direction parallel to the direction of the width of the sheet P, as
shown in FIG. 3. Lateral alignment motors 51a and 52a drive the
lateral alignment boards 51 and 52, respectively, to reciprocate in
the direction of the width. The finisher 20 has, as the finishing
unit, a paddle mechanism 54 which aligns the sheet P on the
processing tray 50 in the longitudinal direction orthogonal to the
direction of the width of the sheet P, and the stapler 56 which
staples the sheet on the processing tray 50.
[0023] The paddle mechanism 54 is rotated about a paddle shaft 55
by a paddle motor 55a. The paddle mechanism 54 has sheet receivers
54a, short paddles 54b, and long paddles 54c. When the paddle
mechanism 54 rotates, the short paddles 54b strike the sheet P
toward the processing tray 50 and the long paddles 54c move the
sheet P toward the stapler 56. A stapler shift motor 56a
reciprocates the stapler 56 in the direction of the width. A
stapler motor 56b drives the stapler 56 for stapling.
[0024] On the processing tray 50, the sheet P falling directly from
the second exit roller pair 28 or via the standby trays 32a and 32b
is placed. The finisher 20 has rear edge stoppers 57 and
longitudinal alignment rollers 58 to the rear edge side in the
carrying direction of the sheet P on the processing tray 50, and
has discharge rollers 59 to the forward edge side in the carrying
direction of the sheet P on the processing tray 50. A longitudinal
alignment motor 80 drives the longitudinal alignment rollers
58.
[0025] A timing belt 72 is laid over a roller shaft 58a of the
longitudinal alignment rollers 58 and a roller shaft 59a of the
discharge rollers 59. The longitudinal alignment motor 80 drives
the discharge rollers 59 via the timing belt 72. The sheet P placed
on the processing tray 50 has its rear edge in the carrying
direction regulated by the rear edge stoppers 57 and is
longitudinally aligned sequentially by the longitudinal alignment
rollers 58, the discharge rollers 59 and the paddle mechanism
54.
[0026] The finisher 20 has a bundle pawl belt 70 having a bundle
pawl 70a. A bundle pawl motor 81 drives the bundle pawl belt 70.
The second carrying mechanism 24 has a pair of ejectors 71a and 71b
which push out a finished sheet bundle T on the processing tray 50.
As an ejector clutch 82 is turned on, the ejectors 71a and 71b are
connected to the bundle pawl motor 81 which drives the bundle pawl
belt 70. At the time of discharging the sheet bundle T on the
processing tray 50, the discharge rollers 59 and the bundle pawl
belt 70 are driven after the ejector clutch 82 is turned on.
[0027] The discharge of the sheet bundle T on the processing tray
50 is first started by the ejectors 71a and 71b and the discharge
rollers 59. After that, the bundle pawl 70a of the bundle pawl belt
70 coming with a delay overtakes the ejectors 71a and 71b and
receives the sheet bundle T. Then, the bundle pawl 70a and the
discharge rollers 59 discharge the sheet bundle T to the second
tray 22. When the ejector clutch 82 is turned off, the ejectors 71a
and 71b return to the discharge start position of the sheet bundle
T.
[0028] The standby trays 32a and 32b are divided in two in the
direction of the width of the sheet P, as shown in FIG. 4. The
standby trays 32a and 32b are moved synchronously with and in the
opposite directions to each other by a link mechanism 36 including
racks 33 and a pinion gear 34. At the time of standby, the standby
trays 32a and 32b are positioning to support both sides of the
sheet P.
[0029] At the time of carrying the sheet P, the standby trays 32a
and 32b open in the direction of the width and drop and carry the
sheet P onto the processing tray 50. The finisher 20 has assist
arms 37 which regulate the movement of the sheet P on the standby
trays 32a and 32b. The distal ends of the assist arms 37 hang down
in the direction of the standby trays 32a and 32b because of the
energizing force of springs 38. The assist arms 37 are energized,
for example, by a link mechanism 37b rotated by a stepping motor
37a, and the assist arms 37 rotate in the direction of arrow f away
from the standby trays 32a and 32b. The standby trays 32a and 32b
and the assist arms 37 constitute a standby unit.
[0030] The sheet receivers 54a of the paddle mechanism 54 support
the rear edge of the sheet P on the standby trays 32a and 32b.
While receiving the sheet P onto the standby trays 32a and 32b from
the second exit roller pair 28, the assist arms 37 are energized by
the link mechanism 37b, thus the assist arms 37 rotate in the
direction of arrow f, and move away from the standby trays 32a and
32b as indicated by the double chain-dotted line in FIG. 2.
[0031] When the reception of the sheet P on the standby trays 32a
and 32b is finished, the energization of the assist arms 37 by the
link mechanism 37b is released and the assist arms 37 hang down in
the direction of the standby trays 32a and 32b because of the
energizing force of the springs 38. By handing down in the
direction of the standby trays 32a and 32b, the assist arms 37
restrains flexure and curling of the sheet P during standby. When
dropping and carrying the sheet P to the processing tray 50 from
the standby trays 32a and 32b, the assist arms 37 presses the rear
edge of the sheet P toward the processing tray 50.
[0032] The finisher 20 has a first sheet sensor 76 which detects a
paper jam in the first carrying mechanism 23, and a second sheet
sensor 77 and a third sheet sensor 78 which detect a paper jam of
the sheet P in the second carrying mechanism 24. The sheet sensors
76 to 78 detect that a paper jam is generated when the sheet
sensors are not turned on even after the lapse of a predetermined
time, or when, after the sheet sensors are turned on by the arrival
of the sheet P, the sheet sensors are not turned off because of the
failure of the rear edge of the sheet P to exit even after the
lapse of a predetermined time.
[0033] Next, the control system of the finisher 20 will be
described mainly with respect to the carrying of the sheet P. As
shown in the block diagram of FIG. 5A, a finisher control circuit
90 as a control unit is connected to a CPU 95 which controls the
entire MFP 10. The finisher control circuit 90 controls a stepping
motor 37a, the lateral alignment motors 51a and 51b, the paddle
motor 55a, the stapler shift motor 56a, the stapler motor 56b, the
longitudinal alignment motor 80, the bundle pawl motor 81, the
ejector clutch 82 or the like. The results of detection by the
first to third sheet sensors 76 to 78 are inputted to the finisher
control circuit 90.
[0034] The MFP 10 outputs various commands to the finisher control
circuit 90. For example, the MFP 10 outputs a command to designate
bundle discharge before starting sheet finishing, a pickup
execution command at the time of starting printing, a command to
notify of the passage of the sheet P through the final sensor, and
the like, to the finisher control circuit 90. In response to these
commands, the finisher control circuit 90 outputs responses to the
MFP 10. The responses include, for example, a delay request to
suspend printing and delay the supply of the sheet in the case of
stapling at two positions, a stop request to stop printing when a
paper jam of the sheet P occurs, and so on. When a timing error
occurs, the finisher control circuit 90 responds to the MFP 10 by
sending a delay request or a pickup stop request or the like in
accordance with the content of the timing error. FIG. 5B shows a
part of a response format 97 to response various kinds of
information from the finisher control circuit 90 to the MFP 10. The
response format 97 sets, for example, normality or abnormality of a
command, an error code, a delay time in the case of a delay
request, and the like.
[0035] When there is a delay request as a response from the
finisher 20, the MFP 10 continues printing on the sheet P that is
already taken out to the printer unit 11 from the paper supply unit
16, whereas the MFP 10 delays the takeout of a new sheet P by the
pickup roller 17 by a predetermined time until the timing error is
canceled.
[0036] When there is a pickup stop request as a response from the
finisher 20, the MFP 10 stops the takeout of a new sheet P by the
pickup roller 17, whereas the MFP 10 continues printing on the
sheet P that is already taken out to the printer unit 11 from the
paper supply unit 16 before the pickup stop request, and discharges
the sheet P from the paper discharge rollers 12. By the way, when
there is a pickup stop request from the finisher 20, the MFP 10 may
also stop printing on the sheet P that is already taken out to the
printer unit 11 from the paper supply unit 16 and only continues
carrying the sheet in the direction of the paper discharge rollers
12.
[0037] When a paper jam error of the sheet P, which is a first
error, occurs between the entrance roller pair 26 and the second
exit roller pair 28, for example, as shown in FIG. 6, the finisher
control circuit 90 stops the driving system of the finisher 20 and
notifies the MFP 10 of the paper jam error and also notifies the
MFP 10 of a stop request to stop printing. The notification of the
paper jam error and the notification of the stop request are sent
in the same response from the finisher control circuit 90 to the
MFP 10.
[0038] In accordance with the response from the finisher control
circuit 90, the MFP 10 displays the paper jam in the finisher 20 on
the display panel 14a and stops printing. After the finisher 20 and
the MFP 10 are stopped, the user removes the sheets P in the
finisher 20 and the sheet left in the MFP 10 and then restores the
MFP 10.
[0039] When a timing error, which is a second error, occurs as
shown in FIG. 7 or FIG. 8, the finisher control circuit 90 controls
the driving system of the finisher 20 to continue and thus
continues carrying the sheet P discharged from the MPF 10.
Moreover, the finisher control circuit 90 sends the timing error
and a delay request or a stop request as a response to the MFP 10.
FIG. 7 shows the state when a timing error occurs as the discharge
of the sheet bundle T from the processing tray 50 is delayed.
[0040] When the discharge of the sheet bundle T from the processing
tray 50 is delayed, the finisher 20 delays the fall and carrying of
the sheet P from the standby trays 32a and 32b to the processing
tray 50 and continues carrying the sheet P discharged from the MFP
10 during this time, up to the standby trays 32a and 32b. FIG. 8
shows the state when a timing error occurs as the rotation of the
assist arms 37 is delayed.
[0041] When the rotation of the assist arms 37 in the direction of
arrow f is delayed, the finisher 20 continues carrying the sheet P
discharged from the MFP 10, up to the first tray 21. The MFP 10
displays the discharge of the sheet to the first tray 21 on the
display panel 14a and prompts the user to remove the sheet P on the
first tray 21.
[0042] Next, an example of the process of carrying the sheet P in
the finisher 20 when a timing error occurs during bundle carrying
will be described with reference to the flowchart of FIG. 9. After
starting, in the finisher 20, the entrance roller pair 26 receives
the sheet P discharged from the MFP 10 (ACT 100). The finisher
control circuit 90 determines whether preceding processing is
finished in the second carrying mechanism 24 (ACT 102).
[0043] For example, when buffering of the preceding sheet P to the
standby trays 32a and 32b is still continued and the timing for the
assist arms 37 to move away from the standby trays 32a and 32b is
delayed as shown in FIG. 8 (No in ACT 102), the finisher control
circuit 90 determined that there is a timing error in the assist
arms 37 and proceeds to ACT 103. In ACT 103, the finisher 20
continues carrying the sheet P discharged from the MFP 10 toward
the first carrying mechanism 23 instead of the second carrying
mechanism 24 and discharges the sheet P to the first tray 21.
[0044] In ACT 103, the finisher control circuit 90 sends the timing
error of the assist arms 37 and a pickup stop request as a response
to the MFP 10. The MFP 10 stops takeout of a new sheet from the
paper supply unit 16 by the pickup roller 17, whereas the MFP 10
continues printing on the sheet P that is already taken out from
the paper supply unit 16 and discharges the sheet P from the paper
discharge rollers 12. The MFP 10 also displays the discharge of the
sheet to the first tray 21 on the display panel 14a and notifies
the user of the occurrence of the timing error. The finisher 20
discharges the sheet P on which printing is still continued, to the
first tray 21, and ends the finishing. The user removes the sheet P
from the first tray 21 and restores the MFP 10.
[0045] The sheet P that is already taken out to the printer unit
11, despite the delay in the rotation of the assist arms 37 and the
resulting timing error, is not left in the MFP 10 but is carried to
the first tray 21. Therefore, the user can release the timing error
and restore the MFP 10 without carrying out maintenance to remove
the sheet P in the MFP 10. The user' s operation to release the
timing error can be reduced and maintenance performance can be
improved.
[0046] In ACT 102, when the assist arms 37 are away from the
standby trays 32a and 32b (Yes in ACT 102), the finisher 20 carries
the sheet P toward the second carrying mechanism 24 and buffers the
sheet P onto the standby trays 32a and 32b (ACT 106). The finisher
control circuit 90 determines whether the number of the sheets P
buffered on the standby trays 32a and 32b reaches a prescribed
numbers of sheets (for example, 3 sheets) for the standby trays 32a
and 32b. When the number of the sheets P buffered on the standby
trays 32a and 32b reaches the prescribed numbers of sheets (Yes in
ACT 107), the finisher control circuit 90 determines whether
preceding processing on the processing tray 50 is finished (ACT
108).
[0047] For example, when the preceding sheet bundle T is being
discharged from the processing tray 50 and the bundle discharge
timing is delayed as shown in FIG. 7 (No in ACT 108), the finisher
control circuit 90 determines that there is a bundle discharge
timing error and proceeds to ACT 110. In ACT 110, the finisher 20
suspends the fall and carrying of the sheet P from the standby
trays 32a and 32b to the processing tray 50. In ACT 110, the
finisher control circuit 90 sends the bundle discharge timing error
and a delay request until the sheet bundle T is discharged, as a
response to the MFP 10. The MFP 10 suspends the takeout of a new
sheet from the paper supply unit 16 by the pickup roller 17 and
continues printing on the sheets P1 and P2 that are already taken
out from the paper supply unit 16, as shown in FIG. 10 and FIG.
11.
[0048] The finisher 20 buffers the sheets P1 and P2 discharged from
the MFP 10 onto the standby trays 32a and 32b until the bundle
discharged of the preceding sheet bundle T from the processing tray
50 is finished. Therefore, there may be a case where a greater
number of sheets than the prescribed number of sheets are buffered
onto the standby trays 32a and 32b. As the bundle discharge of the
preceding sheet bundle T on the processing tray 50 is finished (Yes
in ACT 108), the standby trays 32a and 32b open in the direction of
the width and drop and carry the buffered sheets P, P1 and P2 onto
the processing tray 50, as shown in FIG. 12.
[0049] After the takeout of a new sheet by the pickup roller 17 is
suspended in ACT 110 and is delayed by a predetermined time, the
MFP 10 causes the pickup roller 17 to take out a new sheet P3 from
the paper supply unit 16, as shown in FIG. 12, in order to resume
printing.
[0050] In the case of continuing the bundle carrying on the
processing tray 50, the finisher control circuit 90 adjusts the
number of times of alignment on the processing tray 50 according to
the number of the sheets P falling and carried from the standby
trays 32a and 32b. In ACT 111, the finisher control circuit 90
determines whether the number of the sheets P to be aligned on the
processing tray 50 is equal to or less than the prescribed number
of sheets to be buffered on the standby trays 32a and 32b.
[0051] When the number of sheets to be aligned on the processing
tray 50 is equal to or less than prescribed number of sheets (Yes
in ACT 111), the finisher control circuit 90 sets the number of
times of alignment to a prescribed number of times (ACT 112). The
prescribed number of times of lateral alignment is, for example,
one reciprocating movement of the lateral alignment boards 51 and
52 for a short-size sheet such as JIS standard A4 size, and two
reciprocating movements of the lateral alignment boards 51 and 52
for sheets of other sizes than the short size.
[0052] The prescribed number of times of longitudinal alignment is,
for example, two irrespective of the sheet size. That is,
longitudinally aligned by rotating the paddle mechanism 54 twice
for all of sheet. While the paddle 54 rotates twice, the
longitudinal alignment rollers 58 are driven and therefore the time
for longitudinal alignment by the longitudinal alignment rollers 58
becomes longer.
[0053] The sheet P on the processing tray 50 is aligned
sequentially by the lateral alignment boards 51 and 52 and the
paddle mechanism 54 (ACT 114). Then, when a sheet bundle T2 reaches
a predetermined number of sheets (Yes in ACT 116), the sheet bundle
T2 is discharged from the processing tray 50 to the second tray 22
(ACT 117) and the finishing ends. When the number of sheets to be
aligned on the processing tray 50 exceeds the prescribed number of
sheets in ACT 111 (No in ACT 111), the finisher control circuit 90
sets the number of times of alignment of the sheet P on the
processing tray 50 to the prescribed number of sheets plus an
additional number of times (ACT 113). The additional number of
times is, for example, 1 to 2 both for lateral alignment and for
longitudinal alignment. When a bundle discharge timing error is
generated, as the number of times of alignment of the sheet P on
the processing tray 50 is adjusted, the sheet P can be aligned
satisfactorily despite the delay in falling and carrying of the
sheet P from the standby trays 32a and 32b to the processing tray
50.
[0054] Despite the occurrence of the bundle discharge timing error,
the finisher 20 continues carrying the sheets without stopping.
Since the takeout of a new sheet by the pickup roller 17 in the MFP
10 is suspended for a predetermined time because of the occurrence
of the bundle discharge timing error, printing and hence carrying
of the sheet are delayed. However, after a delay of a predetermined
time, as the new sheet P3 is taken out from the paper supply unit
16, printing is resumed and sheet carrying in the finisher 20 is
continued. Therefore, despite the occurrence of the timing error,
the finisher 20 continues sheet finishing without troubling the
user.
[0055] According to this embodiment, despite that a timing error
occurs because of a delay in the operation in the finisher 20, the
user does not have to carry out operation to remove the sheet left
in the MFP 10. In the case of a timing error of the assist arms 37,
the sheet left in the MFP 10 is discharged toward the first tray 21
and therefore the user only removes the sheet P discharged to the
first tray 21. In the case of a bundle discharge timing error,
printing and sheet finishing are continued without any operation by
the user. Thus, maintenance is not needed and there is no waste of
sheets.
[0056] The invention is not limited to the embodiment, various
changes and modifications can be made without departing from the
scope of the invention. For example, the structure, operation and
the like of the standby unit or the finishing unit of the sheet
finisher may be arbitrary, and the number of sheets that can be
buffered by the standby unit is not limited. The predetermined time
by which the takeout of sheet is delayed in the case of a bundle
discharge timing error is not limited, either.
[0057] Moreover, the structure of the image forming apparatus is
not limited. For example, the image forming apparatus may have both
a color printer unit and a monochrome printer unit. In the image
forming apparatus having both the color printer unit and the
monochrome printer unit, the printing time differs between the two
printer units. Therefore, when one job includes a color job and a
monochrome job, a timing error may occur. For example, when a
monochrome job is carried out following a color job, sheet
finishing on the preceding color sheet may become delayed, causing
a timing error. In such case, the user's operation to remove the
sheet can be significantly reduced and there is no waste of
sheets.
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