U.S. patent application number 12/267993 was filed with the patent office on 2009-05-21 for image forming system.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Wataru Kawata, Hiroyuki Takahashi.
Application Number | 20090127775 12/267993 |
Document ID | / |
Family ID | 40641060 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090127775 |
Kind Code |
A1 |
Takahashi; Hiroyuki ; et
al. |
May 21, 2009 |
IMAGE FORMING SYSTEM
Abstract
A sheet position detecting portion which detects a position of
the sheet in which the image is formed by the image forming
portion, a control portion which controls a motion of the inverting
portion, and a sheet post-processing apparatus which is connected
to the image forming portion and receives the sheet discharged from
the discharging portion so as to apply an post-processing, and the
control portion can change the motion of the inverting portion
based on a detected information of the sheet position detecting
portion, in such a manner that an interval time of the continuous
sheets becomes equal to or more than a sheet interval time which
the sheet post-processing apparatus can receive the sheet.
Inventors: |
Takahashi; Hiroyuki;
(Abiko-shi, JP) ; Kawata; Wataru; (Kashiwa-shi,
JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
40641060 |
Appl. No.: |
12/267993 |
Filed: |
November 10, 2008 |
Current U.S.
Class: |
271/225 |
Current CPC
Class: |
B65H 2801/27 20130101;
B65H 2301/44522 20130101; B65H 2511/20 20130101; B65H 2513/50
20130101; B65H 2511/22 20130101; B65H 2513/20 20130101; B65H 29/00
20130101; B65H 2301/3331 20130101; B65H 2511/20 20130101; B65H
2220/01 20130101; B65H 2511/22 20130101; B65H 2220/02 20130101;
B65H 2513/20 20130101; B65H 2220/02 20130101; B65H 2513/50
20130101; B65H 2220/02 20130101 |
Class at
Publication: |
271/225 |
International
Class: |
B65H 5/06 20060101
B65H005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2007 |
JP |
2007-296383 |
Claims
1. An image forming system comprising: an image forming portion
which forms an image in a sheet; an inverting portion which inverts
the sheet in which the image is formed by the image forming
portion; a discharging portion which discharges the sheet inverted
by the inverting portion; a sheet position detecting portion which
detects a position of the sheet in which the image is formed by the
image forming portion; a control portion which controls a motion of
the inverting portion; and a sheet post-processing apparatus which
is connected to the image forming portion and receives the sheet
discharged from the discharging portion so as to apply an
post-processing, wherein the control portion can change the motion
of the inverting portion based on a detected information of the
sheet position detecting portion, in such a manner that an interval
time of the continuous sheets becomes equal to or more than a sheet
interval time which the sheet post-processing apparatus can receive
the sheet.
2. The image forming system according to claim 1, wherein the
inverting portion includes a rotating body rotating and conveying
the sheet in which the image is formed by the image forming
portion, in one direction and thereafter rotating and conveying in
an inverting direction, and the control portion is capable of
changing a rotation start timing of the roller in the other
direction based on the detected information of the sheet position
detecting portion, in such a manner that an interval between the
continuous sheets becomes equal to or more than a sheet interval
time which the sheet post-processing apparatus is capable of
receiving.
3. The image forming system according to claim 2, wherein the
control portion delays the rotation start timing of the roller in
the other direction at a time of conveying a subsequent sheet, in
the case that an interval time between continuous preceding sheet
and subsequent sheet detected by the sheet position detecting
portion is shorter than a predetermined time.
4. The image forming system according to claim 1, wherein the
inverting portion conveys the sheet in one direction, temporarily
stops the sheet and thereafter conveys the sheet in the other
direction, the inverting portion starts conveying the sheet in the
other direction and thereafter conveys the sheet to the discharging
portion in a state of slowing down to a predetermined speed, and
the control portion is capable of changing a timing for slowing
down the conveying speed of the sheet based on the detected
information of the sheet position detecting portion after the
inverting portion conveys the sheet in the other direction in such
a manner that an interval time of the continuous sheets becomes
equal to or more than a sheet interval time which the sheet
post-processing apparatus is capable of receiving.
5. The image forming system according to claim 4, wherein the
control portion sets a position starting slowing down a subsequent
sheet after the inverting portion conveys the subsequent sheet in
the other direction to an upstream side, in the case that the
interval time between the continuous preceding sheet and subsequent
sheet detected by the sheet position detecting portion is shorter
than a predetermined time.
6. The image forming system according to claim 1, wherein the
control portion is capable of changing a conveying speed of the
inverting portion based on the detected information of the sheet
position detecting portion in such a manner that an interval time
of the continuous sheets at a time of being discharged from the
discharging portion becomes equal to or more than a sheet interval
time which the sheet post-processing apparatus is capable of
receiving.
7. The image forming system according to claim 1, wherein the
inverting portion includes a rotating body rotating and conveying
the sheet in which the image is formed by the image forming portion
in one direction and thereafter rotating and conveying in an
inverting direction, and the control portion controls a rotation
start timing of the roller in the other direction and a sheet
conveying speed by the roller based on the detected information
from the sheet position detecting portion.
8. The image forming system according to claim 1, wherein the
control portion changes a motion of the inverting portion in such a
manner as to achieve a paper interval time at which the sheet
post-processing apparatus is capable of receiving, in the case that
the interval time of the sheet detected by the sheet position
detecting portion is shorter than a predetermined time.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image forming system in
which a sheet post-processing apparatus can be connected to an
image forming portion.
[0003] 2. Description of the Related Art
[0004] Generally, in the image forming system, in order to enhance
a productivity, a subsequent sheet is sequentially fed without
waiting for an image formation of a preceding sheet. Accordingly, a
plurality of sheets exist in a conveying path. Further, if the
preceding sheet is retarded, the subsequent sheet is temporarily
stopped following the preceding sheet, in such a manner as to
prevent the subsequent sheet from catching up on the preceding
sheet.
[0005] Conventionally, in this kind of image forming system, an
inverse conveying unit is driven at a constant speed or timing, a
conveying speed and a conveying timing of a recording sheet are
changed by a change of a conveying performance, and a dispersion is
generated in a paper interval so as to be an obstacle in the case
of increasing a continuous image forming efficiency. In other
words, it is necessary to set a paper interval wide for avoiding a
conveying failure due to the dispersion of the paper interval. As a
result, it is hard to enhance the image forming efficiency.
[0006] In order to solve the problem mentioned above, there is an
image forming apparatus structured such that a continuous image is
formed always at a constant paper interval, by carrying out a
conveying control correcting a change of a conveying performance of
an inverse conveying unit which tends to be affected by a change
such as an abrasion based on an actuation for a long term (refer to
Japanese Patent Application Laid-Open No. 2002-211815).
[0007] Further, there is an image forming apparatus structured such
that a conveying failure is prevented by defining a distance
interval between sheets constant and inverting the sheet, in
accordance with a speeding up of the image forming apparatus (refer
to Japanese Patent Application Laid-Open No. 2001-240285).
[0008] In these image forming apparatuses, it is not necessary to
take into consideration a dispersion at a time of setting the paper
interval in the continuous image forming, it is possible to narrow
down the paper interval, and it is possible to enhance the
productivity of the image forming apparatus.
[0009] Further, in the conventional sheet post-processing
apparatus, since the paper interval time which can execute the
post-processing is narrower than the paper interval time of the
image forming apparatus so as to afford, the post-processing can be
executed without degrading the productivity, even if the paper
interval dispersion exists within the image forming apparatus.
Japanese Patent Application Laid-Open No. 2002-311659 sets the
sheet interval to which the post-processing apparatus can
correspond. The sheet interval set in the structure of Japanese
Patent Application Laid-Open No. 2002-311659 is set while having a
margin such that the post-processing apparatus can correspond even
if a slip between the sheet and the conveying roller is generated
within the image forming apparatus. Accordingly, there is a limit
for shortening the interval between the sheets within the image
forming apparatus so as to improve the productivity.
[0010] In this case, in an accessory (ACC) such as the sheet
post-processing apparatus receiving the image forming apparatus
having a high productivity in an in-line, the paper interval time
which can execute the post-processing becomes approximately equal
to the paper interval time of the image forming apparatus.
[0011] Accordingly, if the paper interval of the image forming
apparatus becomes shorter than the paper interval time which the
sheet post-processing apparatus can execute the post-processing, at
a time when the paper interval is dispersed in the image forming
apparatus, whereby the sheet is discharged from the image forming
apparatus so as to be sent to the post-processing apparatus, there
is a risk that the paper interval can not be corresponded by the
sheet post-processing apparatus.
[0012] In the conventional paper interval dispersion suppressing
unit (refer to Japanese Patent Application Laid-Open No.
2002-211815), a driving unit of an inverse conveying unit is
controlled in such a manner as to detect a change of a conveying
performance of the inverse conveying unit and achieve a constant
conveying performance based on the detection, however, it does not
take into consideration a paper interval between a preceding paper
under conveying and a subsequent paper.
[0013] Accordingly, in the case that the paper interval changes
suddenly, the paper is discharged from the image forming apparatus
as it is without taking into consideration a receiving condition of
the post-processing apparatus. In other words, in the case that the
paper interval time becomes shorter over the receiving condition of
the post-processing apparatus, there is a possibility that the
post-processing failure is generated.
[0014] Further, in Japanese Patent Application Laid-Open No.
2001-240285, there is described that a speed of the inverting
roller is adjusted in the case of correcting the paper interval
dispersion by the speed of the conveying unit. However, unless a
speed of a downstream roller is simultaneously adjusted, there is
generated a step out of a driving motor for the roller caused by
tugging the sheet from both sides, a damage applied to the sheet
caused by pressing the sheet based on a speed difference between
the inverting roller and the downstream roller. Further, since the
sheet post-processing apparatus is not provided by taking into
consideration the paper interval time which can be post-processed,
for example, if the paper interval time becomes shorter than the
paper interval time which the sheet post-processing apparatus can
correspond to, there is a risk that the paper interval time can not
be corresponded by the sheet post-processing apparatus.
SUMMARY OF THE INVENTION
[0015] A technical feature of the present invention is made by
taking the circumstances mentioned above into consideration, and
the present invention provides an image forming system which can
detect a dispersion in a sheet conveyed within an image forming
portion, and can stably carry out an post-processing while securing
a high image forming productivity.
[0016] The image forming system according to the present invention
has an image forming portion which forms an image in a sheet, an
inverting portion which inverts the sheet in which the image is
formed by the image forming portion, a discharging portion which
discharges the sheet inverted by the inverting portion, a sheet
position detecting portion which detects a position of the sheet in
which the image is formed by the image forming portion, a control
portion which controls a motion of the inverting portion, and a
sheet post-processing apparatus which is connected to the image
forming portion and receives the sheet discharged from the
discharging portion so as to apply an post-processing, wherein the
control portion can change the motion of the inverting portion
based on a detected information of the sheet position detecting
portion, in such a manner that an interval time of the continuous
sheets becomes equal to or more than a sheet interval time which
the sheet post-processing apparatus can receive the sheet.
[0017] According to the present invention, it is possible to adjust
the paper interval time of the sheet discharged from the image
forming portion in a range that the sheet post-processing apparatus
can receive, while securing a high image forming productivity.
[0018] Further features of the present invention will become
apparent from the following description of exemplary embodiments
(with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is an explanatory view of a sheet conveying path of
an image forming system according to an embodiment of the present
invention;
[0020] FIG. 2 is a sequence diagram at a time of conveying the
sheet in the image forming system in FIG. 1;
[0021] FIG. 3 is a block diagram of a control system of the image
forming system in FIG. 1;
[0022] FIG. 4 is a flow chart describing a control of the image
forming system in FIG. 1; and
[0023] FIG. 5 is a flow chart describing another control of the
image forming system in FIG. 1.
DESCRIPTION OF THE EMBODIMENTS
[0024] Embodiments according to the present invention will be
described in detail below with reference to the accompanying
drawings. In this case, dimensions, materials, shapes, relative
arrangements and the like of constructing parts described in this
embodiment are not in effect of limiting the range of this
invention to them, unless otherwise specified.
First Embodiment
[0025] FIG. 1 is a view describing a sheet conveying path of one
embodiment according to an image forming system of the present
invention. FIG. 2 is a sequence diagram at a time of conveying the
sheet in the image forming system in FIG. 1. FIG. 3 is a block
diagram of a control system of the image forming system in FIG. 1.
FIG. 4 is a flow chart describing a control of the image forming
system in FIG. 1.
[0026] In FIG. 1, an image forming system 1 has an image forming
portion 10 and a finisher 100 corresponding to a sheet
post-processing apparatus. The image forming portion 10 includes an
image reader which reads a document image and is not illustrated
and a printer. A document feeding apparatus is mounted to the image
reader. The document feeding apparatus feeds the document which is
set upward on a document tray, one by one from a leading page
through a reading position on a platen glass via a curved path, and
discharges to an external discharge tray.
[0027] In a sheet cassette 11, a sheet S is sequentially fed out by
a sheet feeding roller 12. The fed sheet S is conveyed to a
registration roller 16 which stops its rotating motion by path
rollers 13 and 14. The sheet S conveyed to the registration roller
16 is removed its skew feeding. In the drawing, an image reference
sensor 15 is arranged in a downstream side of the path rollers 13
and 14, and serves as a sheet position detecting portion which
detects a position of the fed sheet S.
[0028] A toner image formed on a photosensitive drum 21 is
transferred to the sheet S in a transfer portion 20 in a state of
aligning the toner image formed on the photosensitive drum 21 with
a position in a conveying direction of the sheet S conveyed from
the registration roller 16, by driving the registration roller 16
at a predetermined timing.
[0029] The transfer portion 20 is structured such that an endless
transferring belt 22 is wound around a drive roller 22a and a
driven roller 22b, and a corona charger (not illustrated) for
transferring is arranged in an approximately opposing portion of
the photosensitive drum 21 in an inner side of the transferring
belt 22.
[0030] Accordingly, it is possible to transfer and convey in a
state that a transferring material is adsorbed to the transferring
belt 22, and the image transferred to the sheet S is fixed by a
fixing portion 17. In this case, an extra toner and a paper powder
on a surface of the transferring belt 22 and a surface of the
photosensitive drum 21 are cleaned.
[0031] The fixing portion 17 fixes a developer image on the sheet S
by thermally pressing the sheet S. The sheet S passing through the
fixing portion 17 is discharged toward a finisher 100 from a
discharge port 27a corresponding to a discharge portion of the
image forming portion 10 via a switching member (a flapper) 18 and
a discharge roller 27. The discharge port 20a in this case is a
portion serving as a sheet delivery portion between the image
forming portion 10 and the finisher 100.
[0032] The sheet S conveyed by the discharge roller 27 and
discharged from the discharge port 27a is received by a receiving
roller 101 of the finisher 100, and is discharged and stacked to a
sheet stack tray 104 by a discharge roller 102 while directing the
image forming surface upward.
[0033] In the case of discharging to the finisher 100 while
directing the image forming surface of the sheet S inversely, the
sheet S discharged form the fixing portion 17 is introduced to an
inverting path in which a first inverting roller 19 is arranged, by
switching the switching member 18.
[0034] In this case, a trailing end of the sheet S is conveyed to a
predetermined amount downstream position of the fixing portion 17
while being sped up, and a second inverting roller 24 is stopped in
such a manner that the sheet trailing end is positioned at a
predetermined amount upstream position (an inverting point) of the
second inverting roller 24, after being conveyed at the
predetermined amount.
[0035] Thereafter, the sheet S is conveyed to the discharge roller
27 side by an inverting conveying roller 26 corresponding to a
conveying portion by inverting the second inverting roller 24, and
is conveyed to the finisher 100. Further, in the drawing, a first
inverting sensor 23 is arranged in an upstream side of the first
inverting roller 19, and detects a position of the sheet S before
being inverted, and a second inverting sensor 25 is arranged in a
downstream side of the second inverting roller 24, and detects a
position of the sheet S after being inverted.
[0036] The finisher 100 carries out each of processes such as a
binding process and the like. The finisher 100 carries out a
process of sequentially incorporating the sheet S discharged from
the image forming portion 10, and aligning a plurality of
incorporated sheets S so as to pack into one bundle, and a staple
process of binding a trailing end of the packed sheet bundle by a
staple 103.
[0037] Further, when the staple of the sheet bundle is selected
from the operation portion, the sheet bundle is bound by the staple
103 and is discharged and stacked to the sheet stack tray 105,
after finishing an post-processing of aligning the trailing end and
a width direction of the sheet S.
[0038] The first and second inverting rollers 19 and 24 are
respectively driven by first and second drivers 19a and 24a, as
illustrated in FIG. 3. Further, the first and second drivers 19a
and 24a are controlled by a control portion 30. The control portion
30 has a computing portion 31, and driving timings and sheet
conveying speeds of the first and second inverting rollers 19 and
24 are calculated based on detected information of the first and
second inverting sensors 23 and 25 and the image reference sensor
15.
[0039] In this case, in FIG. 2, a nominal paper interval time of
the image forming portion 10 is set to A (ms) (refer to FIG. 4).
Reference symbol A denotes a standard operate value calculated
based on a productivity of the image forming system 1. Further, the
paper interval time between a preceding sheet S1 and a subsequent
sheet S2 in the image forming portion 10 including a feeding delay
is set to .DELTA.Tp. The paper interval time .DELTA.Tp between the
preceding sheet S1 and the subsequent sheet S2 in the image forming
portion 10 in this case is calculated based on a result of
detection of the preceding sheet S1 and the subsequent sheet S2 by
the image reference sensor 15. The paper interval time between the
preceding sheet S1 and the subsequent sheet S2 which can be
received by the finisher 100 is set to be equal to or more than
.DELTA.Tf. Further, the paper interval time between the preceding
sheet S1 and the subsequent sheet S2 in the inverting portion is
set to .DELTA.T.
[0040] If the paper interval time at a time of receiving the sheet
becomes less than .DELTA.Tf, the post-processing such as the
alignment of the subsequent sheet S2, the staple 103 and the like
is too later, there is a risk that the post-processing failure is
generated.
[0041] In order to prevent this, the computing portion 31
determines a time .DELTA.Ts1 until the second inverting sensor 25
detects the preceding sheet S1 after the image reference sensor 15
detects the preceding sheet S1. The computing portion 31 determines
a time .DELTA.Ts2 until the second inverting sensor 25 detects the
subsequent sheet S2 after the image reference sensor 15 detects the
subsequent sheet S2. Further, the computing portion 31 calculates a
value obtained by adding the paper interval time .DELTA.Tp between
the preceding sheet S1 and the subsequent sheet S2 which are
detected by the image reference sensor 15, to a difference between
.DELTA.Ts1 and .DELTA.Ts2, as the paper interval time .DELTA.T
between the preceding sheet S1 and the subsequent sheet S2 in the
inverting portion.
[0042] As illustrated in a flowchart in FIG. 4, the control portion
30 transmits a signal to the first and second drivers 19a and 24a
in such a manner that a paper interval time (a sheet interval time
between the preceding sheet and the subsequent sheet in the
discharge port 27a) at a time of discharging the sheet S becomes
equal to or more than .DELTA.Tf in correspondence to the calculated
.DELTA.T. Accordingly, the first and second inverting rollers 19
and 24 are controlled by the control portion 30, and adjust a start
timing and an inverting speed of the sheet S from the inverting
point. The inverting speed in this case means a conveying speed of
the sheet by the second inverting roller 24 after being inverted or
a conveying speed of the sheet by the inverting conveying roller 26
provided in the downstream side of the second inverting roller
24.
[0043] For example, the conveying speed of the preceding sheet S1
is slowed down due to an influence of the fixing portion 17 and a
slip and an abrasion of the first and second inverting rollers 19
and 24. There is considered a case that it is delayed to reach the
inverting point and the subsequent sheet S2 is conveyed faster than
a target conveying speed under the transient influence of the
fixing portion 17 without being affected by a reduction of a
conveying efficiency (refer to a dotted portion in FIG. 2).
[0044] In this case, a start timing of the inverting portion of the
subsequent sheet S2 is delayed. In other words, the start timing at
the inverting point is set to be equal to or more than a paper
interval time .DELTA.Tf which is a limit of receiving the finisher
100 and equal to or less than a paper interval time .DELTA.Tp at
which a productivity of the image forming system 1 does not
degrade. The start timing of the inverting portion means a timing
for inverting the second inverting roller 24 after stopping the
second inverting roller 24 in a state that the sheet rear and is
positioned at a predetermined position in an upstream side of the
second inverting roller 24.
[0045] With such a state, for example, in the case that a time for
which the third sheet S3 reaches the inverting point is longest in
the dispersion (the third sheet S3 is delayed), the inversion is
started by quickening the start timing of the inverting portion
while targeting at a point near .DELTA.Tf. Otherwise, in the case
that the time for which the sheet S3 reaches the inverting point is
shortest in the dispersion (the sheet S3 reaches earlier), the
start timing of the inverting portion is delayed while targeting at
.DELTA.Tp.
[0046] In other words, the paper interval time A of the image
forming portion 10 is compared with .DELTA.Tp (step 1), and in the
case that .DELTA.Tp is larger than the paper interval time A due to
the feeding delay in the upstream side than the image forming
portion, the inversion is carried out according to a normal control
(step 2). In the case that .DELTA.Tp is equal to or less than the
paper interval time A, .DELTA.T is compared with .DELTA.Tp (step
3), and if the paper interval time .DELTA.T at the inverting point
becomes equal to or more than .DELTA.Tp, the start timing of the
first and second inverting rollers 19 and 24 is quickened at the
difference (step 4).
[0047] Accordingly, it is possible to prevent the paper interval
time .DELTA.T from becoming short at the inverting point of the
subsequent sheet S2. In the case that the paper interval time
.DELTA.T at the inverting point becomes shorter than .DELTA.Tp,
.DELTA.T is compared with the paper interval time .DELTA.Tf of the
receiving condition of the finisher 100 (step 5), and if .DELTA.T
is equal to or more than .DELTA.Tf, the inversion is carried out as
it is in accordance with the normal control (step 6). In the case
that .DELTA.T is smaller than .DELTA.Tf, the start timing of the
inverting roller (the timing at which the second inverting roller
24 is inverted) is delayed only at the difference between .DELTA.Tf
and .DELTA.T, in such a manner that the paper interval becomes
equal to or more than the paper interval time .DELTA.Tf which can
be received by the finisher 100 (step 7).
[0048] As mentioned above, even in the case that the paper interval
dispersion is generated within the image forming portion 10, it is
possible to maintain a stable conveying performance without
degrading the productivity of the image forming system 1, while
satisfying the receiving condition of the finisher 100.
Second Embodiment
[0049] In a second embodiment according to the present invention,
in the case of discharging the sheet S to the finisher 100 while
inverting the image forming surface of the sheet S after forming
the image by the image forming portion 10, the sheet S is sped up
in a convey region by the inverting conveying roller 26.
[0050] Further, the sheet leading end is slowed down to a speed
which can received the finisher 100 at a predetermined amount
upstream position of the discharge roller 27, and the sheet is
discharged from the discharge port 27a by the discharge roller 27.
In this case, the computing portion 31 calculates .DELTA.T obtained
by adding .DELTA.Tp to the difference between .DELTA.Ts2 and
.DELTA.Ts1. A sheet conveying speed or a speed change timing by the
inverting conveying roller 26 is controlled in such a manner that
the paper interval becomes equal to or more than .DELTA.Tf
corresponding to the receiving condition of the finisher 100 and
becomes equal to or less than .DELTA.Tp at which the productivity
of the image forming system 1 does not degrade.
[0051] These controls will be specifically described with reference
to FIG. 5. First, .DELTA.Tp is compared with the paper interval
time A of the image forming portion 10 (step 1), and in the case
that .DELTA.Tp is larger than A due to the feeding delay, the
inversion is carried out in accordance with a normal control (step
2).
[0052] In the case that .DELTA.Tp is equal to or less than the
paper interval time A, .DELTA.Tp is compared with the paper
interval time .DELTA.T at the inverting point (step 3), and if
.DELTA.T is equal to or more than .DELTA.Tp, a distance at which
the speeding up is carried out in an inverting path is made longer
at the difference, and a position starting the slowing down is set
to a downstream side (step 4).
[0053] Accordingly, it is possible to prevent the paper interval
time .DELTA.T from becoming short at the inverting point of the
subsequent sheet S2. In the case that the paper interval time
.DELTA.T at the inverting point becomes shorter than .DELTA.Tp,
.DELTA.T is compared with .DELTA.Tf (step 5), and it is determined
whether or not .DELTA.T is equal to or more than the paper interval
time .DELTA.Tf of the receiving condition of the finisher 100.
[0054] If .DELTA.T is equal to or more than .DELTA.Tf, the
inversion is carried out as it is in accordance with the normal
control (step 6). In the case that .DELTA.T is smaller than
.DELTA.Tf, the distance is made shorter by carrying out the
speed-up conveying in the inverting path at the difference between
.DELTA.Tf and .DELTA.T in such a manner that the paper interval
becomes equal to or more than .DELTA.Tf, and the position starting
slowing down is set to an upstream side (step 7).
[0055] As mentioned above, it is possible to maintain the stable
conveying performance without degrading the productivity of the
image forming system 1 by controlling in such a manner as to adjust
the slowing down point.
[0056] In this case, as the first embodiment, the embodiment that
the paper interval is adjusted in such a manner as to be received
by the finisher 100 by controlling the start timings of the first
and second inverting rollers 19 and 24 is described. Further, as
the second embodiment, the embodiment that the paper interval is
adjusted in such a manner that the finisher 100 can receive by
controlling the speed of the inverting conveying roller 26 is
described. However, the structure may be made such as to adjust so
as to achieve such a paper interval that the finisher 100 can
receive by controlling both the start timings of the first and
second inverting rollers 19 and 24 and the speed of the inverting
conveying roller 26.
Third Embodiment
[0057] In a third embodiment according to the present invention,
the image forming portion 10 to which a plurality of finishers 100
can be connected receives the information of the receiving time set
in each of the finishers 100 by the image forming portion 10 side.
It is possible to control the inverting timings of the first and
second inverting rollers 19 and 24 and the conveying speed of the
inverting conveying roller 26 such as to discharge at a paper
interval time which is equal to or more than a lower limit value of
the receiving time of the finisher 100 and equal to or more than
such a paper interval time as to prevent the productivity from
degrading based on the information.
[0058] As mentioned above, the information of the receiving paper
interval time is received in the image forming portion 10 side from
the finisher 100, and the paper interval time of the discharge is
controlled in correspondence to the finisher 100. Accordingly, it
is possible to obtain the image forming system 1 which can maintain
the stable conveying performance in correspondence to the various
accessories without degrading the productivity.
[0059] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0060] This application claims the benefit of Japanese Patent
Application No. 2007-296383, filed Nov. 15, 2007, which is hereby
incorporated by reference herein in its entirety.
* * * * *