U.S. patent application number 16/538670 was filed with the patent office on 2020-03-05 for paper feeder and image forming system.
This patent application is currently assigned to KONICA MINOLTA, INC.. The applicant listed for this patent is KONICA MINOLTA, INC.. Invention is credited to Yoshiyuki MASUDA.
Application Number | 20200071102 16/538670 |
Document ID | / |
Family ID | 69640923 |
Filed Date | 2020-03-05 |
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United States Patent
Application |
20200071102 |
Kind Code |
A1 |
MASUDA; Yoshiyuki |
March 5, 2020 |
PAPER FEEDER AND IMAGE FORMING SYSTEM
Abstract
A paper feeder sucking and feeding a paper sheet from a stack of
paper sheets loaded on a paper table, the paper feeder includes: a
pair of blowing ports that are disposed across a stack of paper
sheets and blow air toward a side surface of the stack of paper
sheets to float a paper sheet; and a hardware processor that
performs blowing control of blowing air to float a paper sheet in a
first operation mode in which a height of one blowing ports is
different from a height of another blowing ports.
Inventors: |
MASUDA; Yoshiyuki; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KONICA MINOLTA, INC. |
Tokyo |
|
JP |
|
|
Assignee: |
KONICA MINOLTA, INC.
Tokyo
JP
|
Family ID: |
69640923 |
Appl. No.: |
16/538670 |
Filed: |
August 12, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H 3/12 20130101; B65H
3/48 20130101; B65H 7/02 20130101; B65H 2511/414 20130101; B65H
2301/4461 20130101; B65H 2515/112 20130101; B65H 5/228 20130101;
B65H 2511/20 20130101; B65H 3/128 20130101 |
International
Class: |
B65H 5/22 20060101
B65H005/22; B65H 3/48 20060101 B65H003/48; B65H 3/12 20060101
B65H003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2018 |
JP |
2018-165607 |
Claims
1. A paper feeder sucking and feeding a paper sheet from a stack of
paper sheets loaded on a paper table, the paper feeder comprising:
a pair of blowing ports that are disposed across a stack of paper
sheets and blow air toward a side surface of the stack of paper
sheets to float a paper sheet; and a hardware processor that
performs blowing control of blowing air to float a paper sheet in a
first operation mode in which a height of one blowing ports is
different from a height of another blowing ports.
2. A paper feeder sucking and feeding a paper sheet from a stack of
paper sheets loaded on a paper table, the paper feeder comprising:
a pair of blowing ports that are disposed across a stack of paper
sheets and blow air toward a side surface of the stack of paper
sheets to float a paper sheet; a sheet holder that abuts on a
floated paper sheet from above to regulate a floating height of the
paper sheet; and a hardware processor that performs blowing control
of blowing air to float a paper sheet in a second operation mode in
which a height of the at least one sheet holder corresponding to
one side surface of a stack of paper sheets is different from a
height of the at least one sheet holder corresponding to another
side surface of the stack of paper sheets.
3. A paper feeder sucking and feeding a paper sheet from a stack of
paper sheets loaded on a paper table, the paper feeder comprising:
a pair of blowing ports that are disposed across a stack of paper
sheets and blow air toward a side surface of the stack of paper
sheets to float a paper sheet; and a hardware processor that
performs blowing control of blowing air to float a paper sheet in a
third operation mode in which an amount of air blown from one
blowing port is different from an amount of air blown from another
blowing port.
4. The paper feeder according to claim 1, further comprising a
sheet holder that abuts on a floated paper sheet from above to
regulate a floating height of the paper sheet, wherein the hardware
processor performs the blowing control in a second operation mode
in which a height of the at least one sheet holder corresponding to
one side surface of a stack of paper sheets is different from a
height of the at least one sheet holder corresponding to another
side surface of the stack of paper sheets, in addition to the first
operation mode.
5. The paper feeder according to claim 1, wherein the hardware
processor performs the blowing control in a third operation mode in
which an amount of air blown from the one blowing port is different
from an amount of air blown from the other blowing port, in
addition to the first operation mode.
6. The paper feeder according to claim 2, wherein the hardware
processor performs the blowing control in a third operation mode in
which an amount of air blown from the one blowing port is different
from an amount of air blown from the other blowing ports, in
addition to the second operation mode.
7. The paper feeder according to claim 1, further comprising a
sheet holder that abuts on a floated paper sheet from above to
regulate a floating height of the paper sheet, wherein the hardware
processor performs the blowing control in a second operation mode
in which a height of the at least one sheet holder corresponding to
one side surface of a stack of paper sheets is different from a
height of the at least one sheet holder corresponding to another
side surface of the stack of paper sheets and a third operation
mode in which an amount of air blown from one of the blowing ports
is different from an amount of air blown from the other of the
blowing ports, in addition to the first operation mode.
8. The paper feeder according to claim 1, further comprising a duct
that is connected to each of the blowing ports to guide air blown
from a blower to the blowing port, wherein the duct is movable in a
vertical direction to adjust the height of the blowing port.
9. The paper feeder according to claim 8, wherein the duct is
movable in a vertical direction by a pressure of air.
10. The paper feeder according to claim 9, further comprising a
lock mechanism that regulates the movement of the duct to adjust
the height of the blowing port.
11. The paper feeder according to claim 2, wherein the at least one
sheet holder is provided above the blowing ports.
12. The paper feeder according to claim 11, further comprising a
movable mechanism that adjusts the height of the at least one sheet
holder.
13. The paper feeder according to claim 1, wherein the hardware
processor further includes, as an operation mode in the blowing
control, a normal operation mode in which the height of the one
blowing port and the height of the other blowing port are aligned,
and switches, based on one or both of information on a paper sheet
and a floating state of a paper sheet, between the normal operation
mode and the first operation mode.
14. The paper feeder according to claim 13, wherein in the first
operation mode, the height of the one of the blowing ports or the
height of the other of the blowing port is lower than that in the
normal operation mode.
15. The paper feeder according to claim 2, wherein the hardware
processor further includes, as an operation mode in the blowing
control, a normal operation mode in which the height of the sheet
holder corresponding to one side surface of a stack of paper sheets
and the height of the sheet holder corresponding to another side
surface of the stack of paper sheets are aligned, and switches,
based on one or both of information on a paper sheet and a floating
state of a paper sheet, between the normal operation mode and the
second operation mode.
16. The paper feeder according to claim 3, wherein the hardware
processor further includes, as an operation mode in the blowing
control, a normal operation mode in which the amount of air blown
from the one blowing port is equal to the amount of air blown from
the other blowing port, and switches, based on one or both of
information on a paper sheet and a floating state of a paper sheet,
between the normal operation mode and the third operation mode.
17. The paper feeder according to claim 13, wherein the hardware
processor switches the operation modes on the basis of a time from
floating of a paper sheet to suction of the paper sheet by a sheet
suction portion positioned above a stack of paper sheets.
18. The paper feeder according to claim 5, wherein when the amount
of air blown from the one blowing port is different from the amount
of air blown from the other blowing port, the hardware processor
sets a height of the blowing port blowing a larger amount of air
lower than a height of the blowing port blowing a smaller amount of
air.
19. The paper feeder according to claim 6, wherein when the amount
of air blown from the one blowing port is different from the amount
of air blown from the other blowing port, the hardware processor
sets a height of the sheet holder blowing a smaller amount of air
lower than a height of the sheet holder blowing a larger amount of
air.
20. An image forming system comprising: the paper feeder according
to claim 1; and an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder.
21. An image forming system comprising: a paper feeder that sucks
and feeds a paper sheet from a stack of paper sheets loaded on a
paper table; an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder; and a hardware processor
that controls the paper feeder and the image forming apparatus;
wherein the paper feeder includes a pair of blowing ports that are
disposed across a stack of paper sheets and blow air toward a side
surface of the stack of paper sheets to float a paper sheet, and
the hardware processor performs blowing control of blowing air to
float a paper sheet in a first operation mode in which a height of
one blowing port is different from a height of another blowing
port.
22. An image forming system comprising: a paper feeder that sucks
and feeds a paper sheet from a stack of paper sheets loaded on a
paper table; an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder; and a hardware processor
that controls the paper feeder and the image forming apparatus;
wherein the paper feeder includes: a pair of blowing ports that are
disposed across a stack of paper sheets and blow air toward a side
surface of the stack of paper sheets to float a paper sheet, and; a
sheet holder that abuts on a floated paper sheet from above to
regulate a floating height of the paper sheet, and the hardware
processor performs blowing control of blowing air to float a paper
sheet in a second operation mode in which a height of the at least
one sheet holder corresponding to one side surface of a stack of
paper sheets is different from a height of the at least one sheet
holder corresponding to another side surface of the stack of paper
sheets.
23. An image forming system comprising: a paper feeder that sucks
and feeds a paper sheet from a stack of paper sheets loaded on a
paper table; an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder; and a hardware processor
that controls the paper feeder and the image forming apparatus;
wherein the paper feeder includes a pair of blowing ports that are
disposed across a stack of paper sheets and blow air toward a side
surface of the stack of paper sheets to float a paper sheet, and
the hardware processor performs blowing control of blowing air to
float a paper sheet in a third operation mode in which an amount of
air blown from one blowing port is different from an amount of air
blown from another blowing port.
24. An image forming system comprising: the paper feeder according
to claim 2; and an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder.
25. An image forming system comprising: the paper feeder according
to claim 3; and an image forming apparatus that forms an image on a
paper sheet fed from the paper feeder.
Description
[0001] The entire disclosure of Japanese patent Application No.
2018-165607, filed on Sep. 5, 2018, is incorporated herein by
reference in its entirety.
BACKGROUND
Technological Field
[0002] The present invention relates to a paper feeder and an image
forming system.
Description of the Related Art
[0003] Image forming systems are known to serially perform various
processing including image formation. Such an image forming system
is configured by arranging one or more devices in series according
to a specification required by a user. An apparatus constituting
the image forming system includes, in addition to an image forming
apparatus that forms an image, for example, a paper feeder (large
capacity paper feeder) that holds a large amount of paper sheets
and feeds the paper sheets to the image forming apparatus.
[0004] The paper feeder includes a paper table that loads a
plurality of paper sheets stacked in a thickness direction, that
is, a stack of paper sheets thereon, and a sheet feed portion that
feeds paper sheets. The sheet feed portion feeds a paper sheet
(uppermost paper sheet) one by one from the stack of paper sheets
loaded on the paper table. As the sheet feed portion, a
configuration for sucking and feeding a paper sheet is known, and
the paper feeder includes a side surface blowing portion that blows
air to a side surface of the stack of paper sheets in a sheet
transport direction to float a paper sheet.
[0005] This type of paper feeder floats not only the uppermost
paper sheet but also the second and subsequent paper sheets due to
air blowing. Therefore, the suction of the uppermost paper sheet by
the sheet feed portion requires fanning the second and subsequent
paper sheets positioned under the uppermost paper sheet to feed the
uppermost paper sheet. Such a configuration requires a long time to
float a paper sheet, reducing productivity. On the other hand, to
ensure the productivity, there is no sufficient time to fan the
paper sheets, and multi-feed is likely to be caused. In addition,
in a case where it is difficult to float a paper sheet, suction of
the paper sheet is late so that no paper sheet may be fed.
[0006] Therefore, for example, JP 2014-1061 A discloses a method of
increasing the amount of air blown to a side surface of a stack of
paper sheets.
[0007] However, the amount of air blown to the side surface of the
stack of paper sheets depends on the configuration of a blower.
Therefore, there is a problem that in a case where a sufficient
floating state cannot be obtained even with the maximum amount of
air of the blower, a blower outputting higher amount of air is
required.
SUMMARY
[0008] The present invention has been made in view of the above
circumstances, and an object of the invention is to provide a paper
feeder and an image forming system which are capable of achieving
stable sheet feed performance by reducing a time required to float
a paper sheet.
[0009] To achieve the abovementioned object, according to an aspect
of the present invention, there is provided a paper feeder sucking
and feeding a paper sheet from a stack of paper sheets loaded on a
paper table, and the paper feeder reflecting one aspect of the
present invention comprises: a pair of blowing ports that are
disposed across a stack of paper sheets and blow air toward a side
surface of the stack of paper sheets to float a paper sheet; and a
hardware processor that performs blowing control of blowing air to
float a paper sheet in a first operation mode in which a height of
one blowing ports is different from a height of another blowing
ports.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The advantages and features provided by one or more
embodiments of the invention will become more fully understood from
the detailed description given hereinbelow and the appended
drawings which are given by way of illustration only, and thus are
not intended as a definition of the limits of the present
invention:
[0011] FIG. 1 is a front view schematically illustrating a
configuration of an image forming system according to an embodiment
of the present invention;
[0012] FIG. 2 is a front view schematically illustrating a
configuration of a paper feed unit;
[0013] FIG. 3 is a diagram schematically illustrating the
configurations of side end blowing portions;
[0014] FIGS. 4A to 4C are explanatory diagrams illustrating a side
end blowing portion in detail;
[0015] FIG. 5 is an explanatory diagram of a normal operation
mode;
[0016] FIG. 6 is an explanatory diagram of a first operation
mode;
[0017] FIG. 7 is an explanatory diagram of a second operation
mode;
[0018] FIG. 8 is an explanatory diagram of a third operation
mode;
[0019] FIG. 9 is a flowchart illustrating a sheet feeding
process;
[0020] FIG. 10 is a table defining relationships between operation
modes and information on paper sheets; and
[0021] FIG. 11 is an explanatory diagram of a modification of a
sheet holder.
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] Hereinafter, one or more embodiments of the present
invention will be described with reference to the drawings.
However, the scope of the invention is not limited to the disclosed
embodiments.
[0023] FIG. 1 is a front view schematically illustrating a
configuration of an image forming system according to the present
embodiment. The image forming system performs predetermined
processing including image formation on a paper sheet P and
includes a plurality of apparatuses. The image forming system
according to the present embodiment includes an image forming
apparatus 100 and a large capacity paper feeder 200. These
apparatuses are arranged in the order of the large capacity paper
feeder 200 and the image forming apparatus 100 from an upstream
side to a downstream side in a sheet transport direction, but the
individual apparatuses may be accommodated in the same housing.
[0024] The image forming apparatus 100 forms an image on a paper
sheet P fed from the large capacity paper feeder 200 or a paper
sheet P held in the image forming apparatus 100. The image forming
apparatus 100 is, for example, an electrophotographic image forming
apparatus and, in particular, a so-called tandem color image
forming apparatus having a plurality of photoreceptors disposed in
a vertical direction to face one intermediate transfer belt and
forming a full-color image. The image forming apparatus 100 mainly
includes a document reader SC, four sets of image forming units
10Y, 10M, 10C, and 10K, a fuser 40, and a control unit 50, and
these elements are stored in one casing.
[0025] The document reader SC scans and exposes a document by using
an exposure device and reads reflected light from the document by
using a line image sensor to obtain an image signal. The image
signal is subjected to processing, such as A/D conversion, shading
correction, and compression, and then is input as image data to the
control unit 50. The image data input to the control unit 50 is not
limited to image data read by the document reader SC and may
include, for example, image data received from a personal computer,
which is connected to the image forming apparatus 100, or another
image forming apparatus or image data read from a portable
recording medium, such as a semiconductor memory.
[0026] The four image forming units 10Y, 10M, 10C, and 10K include
the image forming unit 10Y forming a yellow (Y) image, the image
forming unit 10M forming a magenta (M) image, the image forming
unit 10C forming a cyan (C) image, and the image forming unit 10K
forming a black (K) image.
[0027] The image forming unit 10Y includes a photoreceptor drum 11Y
and a charged portion, an optical writing unit, a developing
device, and a drum cleaner which are disposed around the
photoreceptor drum 11Y. The photoreceptor drum 11Y has a surface
which is uniformly charged by the charged portion, and thus a
latent image is formed on the photoreceptor drum 11Y by scanning
exposure by the optical writing unit. In the developing device,
toner develops the latent image on the photoreceptor drum 11Y to
visualize the latent image. Thereby, an image (toner image)
corresponding to yellow is formed on the photoreceptor drum 11Y.
Images formed on the photoreceptor drum 11Y are sequentially
transferred to a predetermined position on an intermediate transfer
belt 15, which is an endless belt, by a primary transfer
roller.
[0028] The remaining image forming units 10M, 10C, and 10K include
photoreceptor drums 11M, 11C, and 11K and charged portions, optical
writing units, developing devices, and drum cleaners which are
disposed around the photoreceptor drums 11M, 11C, and 11K, and
detailed configurations thereof are similar to that of the image
forming unit 10Y.
[0029] An image transferred onto the intermediate transfer belt 15
is transferred by a secondary transfer roller 16 onto a paper sheet
P transported at predetermined timing by a paper transport unit 20.
The secondary transfer roller 16 is disposed in pressure-contact
with the intermediate transfer belt 15, and a transfer nip is
formed between the secondary transfer roller 16 and the
intermediate transfer belt 15.
[0030] The paper transport unit 20 transports a paper sheet P fed
from a paper tray 21 by a paper feed roller 22 or a paper sheet P
fed from the large capacity paper feeder 200 through a transport
path. The paper transport unit 20 includes transport rollers, a
conveyance guide, and the like. In addition, a paper exit roller 23
and a switching gate 24, which will be described later, also
partially constitute the paper transport unit 20.
[0031] The fuser 40 is configured to fix an image having been
transferred onto a paper sheet P. The fuser 40 is constituted by,
for example, a pair of fusing rollers that are brought into
pressure contact with each other to form a fusing nip, and a heater
that heats one of the fusing rollers. While the paper sheet P
passes through the fusing nip, the fuser 40 fixes the transferred
image on the paper sheet P by using the pressure of the pair of
fusing rollers and the heat of the fusing roller. The paper sheet P
subjected to the fixing processing is discharged to the outside of
the apparatus by the paper exit roller 23.
[0032] To form an image also on the back side of the paper sheet P,
the paper sheet P, on the front side of which the image has been
formed is transported to the sheet refeed path by the switching
gate 24. In the sheet refeed path, a trailing end of the
transported paper sheet P is held by reverse rollers, and then, the
paper sheet P is turned over by reverse feeding. The paper sheet P
which has been turned over is transported by a plurality of
transport rollers and joined to a transport path positioned
upstream from the secondary transfer roller 16 to form an image on
the back side of the paper sheet.
[0033] The control unit 50 controls the operation of the image
forming apparatus 100. As the control unit 50, a microcomputer
mainly including a CPU, a ROM, a RAM, and an I/O interface is
usable. The CPU executes various programs to control the operation
of the image forming apparatus 100 (processor). The ROM stores
various programs executed by the CPU, in the form of program codes
readable by the CPU. The ROM also stores data necessary for
execution of the programs. The RAM is a memory serving as a storage
area for work. The programs and data stored in the ROM are loaded
into the RAM when read by the CPU. Then, the CPU performs various
processing on the basis of the programs and data loaded into the
RAM.
[0034] An operation panel 60 is an input unit capable of inputting
desired information according to information displayed on a
display. For the operation panel 60, a touch panel system or the
like can be employed. The user can set the contents of a job
(information (sheet size, paper type, etc.) about the paper sheet
P, density, magnification, etc. of an image) through the operation
on the operation panel 60. The set information is acquired by the
control unit 50. The operation panel 60 is controlled by the
control unit 50 to also function as a display unit for displaying
various information to the user.
[0035] The large capacity paper feeder 200 is a paper feeder for
feeding paper sheets P. The large capacity paper feeder 200
includes one or more paper feed units 210, for example, three paper
feed units 210 disposed in upper, middle, and lower stages, and a
control unit 250, and these elements are stored in one casing.
[0036] FIG. 2 is a front view schematically illustrating a
configuration of the paper feed unit 210. The paper feed unit 210
stores a plurality of paper sheets P (stack of paper sheets), and
feeds a paper sheet P (uppermost paper sheet P) one by one from the
stack of paper sheets. The paper feed unit 210 mainly includes a
paper table 211, a leading end adjusting member 212, a trailing end
adjusting member 213, a side end adjusting member 214, a sheet feed
portion 220, a leading end blowing portion 230, and a side end
blowing portion 240. The paper feed unit 210 is provided with a
guide rail 215 so that the paper feed unit 210 is drawable from the
casing of the large capacity paper feeder 200.
[0037] In the paper feed unit 210, the stack of paper sheets is
loaded on the paper table 211. The paper table 211 is provided with
an electrically-driven lift mechanism so as to move in a vertical
direction.
[0038] The leading end adjusting member 212 regulates a leading end
of each paper sheet P loaded on the paper table 211, that is, a
surface (leading end surface) of the stack of paper sheets
positioned downstream from the leading end adjusting member 212 in
a sheet transport direction.
[0039] The trailing end adjusting member 213 regulates the trailing
end of each paper sheet P loaded on the paper table 211, that is, a
surface (trailing end face) of the stack of paper sheets positioned
upstream from the trailing end adjusting member 213 in the sheet
transport direction. The trailing end adjusting member 213 is
configured to be movable in the sheet transport direction, and the
position thereof is adjusted according to sheet size.
[0040] In the trailing end adjusting member 213, a height sensor
(not illustrated) is disposed to detect the height of the stack of
paper sheets loaded on the paper table 211. The control unit 250
drives the lift mechanism on the basis of a signal from the height
sensor to control the paper table 211 to lift and lower. Owing to
this control, the uppermost paper sheet P of the stack of paper
sheets loaded on the paper table 211 is maintained at a constant
height.
[0041] The side end adjusting member 214 regulates a side end of
each paper sheet P loaded on the paper table 211, that is, a
surface (side surface) of the stack of paper sheets parallel to the
sheet transport direction. The side end adjusting member 214 is
provided at two places corresponding to both side surfaces (right
and left side surfaces) of the stack of paper sheets. In other
words, the side end adjusting members 214 are arranged to face each
other across the stack of paper sheets. One or both of the side end
adjusting members 214 is configured to be movable in a direction
(sheet width direction) orthogonal to the sheet transport
direction, and the position thereof is adjusted according to sheet
size.
[0042] The sheet feed portion 220 is disposed above the paper table
211 (paper sheet P) so as to face the paper table 211. The sheet
feed portion 220 is disposed to be separated from the uppermost
paper sheet P of the stack of paper sheets loaded on the paper
table 211 by a fixed distance. The sheet feed portion 220 sucks a
paper sheet P (uppermost paper sheet P) having been floated from
the stack of paper sheets by blowing air and feeds the paper sheet
P to the transport path. The sheet feed portion 220 mainly includes
a sheet transport portion 221 and a suction portion 226.
[0043] The sheet transport portion 221 has a function of
transporting (feeding) a sucked paper sheet P forward and includes
an endless suction belt 221a, a driving roller 221b, and driven
rollers 221c, and the suction belt 221a is stretched around the
driving roller 221b and the driven rollers 221c. The suction belt
221a turns as the driving roller 221b is rotationally driven, and a
belt area (lower belt area) facing the paper sheet P moves in the
sheet transport direction. The suction belt 221a is provided with a
plurality of through-holes (not illustrated) each having a small
diameter.
[0044] The suction portion 226 sucks a floated paper sheet P onto
the suction belt 221a. The suction portion 226 is disposed inside
the suction belt 221a and faces the paper sheet P across the
suction belt 221a. The suction portion 226 includes a suction fan
for sucking air, and a duct disposed inside the suction belt 221a
to guide air to the suction fan. At a lower portion of the duct, a
suction port facing the suction belt 221a is defined. Operation of
the suction fan reduces the pressure inside the suction belt 221a
to a negative pressure. Thus, the flow of air from the lower side
of the suction belt 221a to the duct is formed, and the paper sheet
P is sucked.
[0045] Furthermore, the sheet feed portion 220 is provided with a
suction sensor (not illustrated) that detects suction of a paper
sheet P to the suction belt 221a. Information detected by the
suction sensor is read by the control unit 250.
[0046] The leading end blowing portion 230 is disposed on the
leading end surface of the stack of paper sheets and in the
vicinity of the sheet feed portion 220. The leading end blowing
portion 230 blows air to the stack of paper sheets loaded on the
paper table 211 from the leading end side thereof. The air blow
introduces air between the uppermost paper sheet P and the second
and subsequent sheets P, fanning the uppermost paper sheet P and
the second and subsequent paper sheets P.
[0047] The leading end blowing portion 230 mainly includes a blower
231 and a blowing port 232. The blower 231 is, for example, a
multi-vane fan (sirocco fan). The blowing port 232 blows air blown
from the blower 231 toward the top of the stack of paper
sheets.
[0048] FIG. 3 is a diagram schematically illustrating the
configurations of the side end blowing portions 240. The side end
blowing portions 240 are disposed at two places corresponding to
right and left side surfaces of the stack of paper sheets. In the
present embodiment, the side end blowing portions 240 are provided
inside the side end adjusting members 214. Similar to the pair of
side end adjusting members 214, a pair of the side end blowing
portions 240 are arranged to face each other across the stack of
paper sheets. The individual side end blowing portions 240 are
configured to be symmetrical about the stack of paper sheets.
[0049] Each of the side end blowing portions 240 includes a blower
241, a duct 242, a blowing port 243, and a sheet holder 244. The
blower 241 is, for example, a multi-vane fan (sirocco fan) and
blows air. The duct 242 guides air blown from the blower 241 to the
blowing port 243. The duct 242 is configured so that air flows in a
vertical direction. The blowing port 243 is connected to an upper
portion of the duct 242. The blowing port 243 blows air flowing
through the duct 242 toward a side surface of the stack of paper
sheets. Air blown from the blowing port 243 to the side surface of
the stack of paper sheets functions as air for floating an
uppermost paper sheet P. The sheet holder 244 abuts on the floated
uppermost paper sheet P from above to regulate a floating height of
the paper sheet P. The sheet holder 244 is provided above the
blowing port 243 and extends toward the center of the stack of
paper sheets. A movable mechanism 245 for adjusting the height of
the sheet holder 244 is connected to the sheet holder 244.
Operation of the movable mechanism 245 is controlled by the control
unit 250.
[0050] FIGS. 4A to 4C are explanatory diagrams illustrating a side
end blowing portion 240 in detail. In the side end blowing portion
240, the duct 242 is movable in a vertical direction within a
movable range from an upper limit position to a lower limit
position. When the blower 241 is not in operation, the duct 242
stays at the lower limit position by its own weight, as illustrated
in FIG. 4A. On the other hand, when the blower 241 is in operation,
the duct 242 rises to the upper limit position by the pressure of
air blown from the blower 241, as illustrated in FIG. 4B, and keeps
staying at that position. When the blower 241 stops, the duct 242
is lowered to the lower limit position by its own weight, as
illustrated in FIG. 4A.
[0051] As one of the features of the present embodiment, each of
the side end blowing portions 240 includes a lock mechanism 246.
The lock mechanism 246 restricts the movement of the duct 242 and
adjusts the height of the blowing port 243. For the lock mechanism
246, a method using an abutment member or a method using a solenoid
can be considered. The abutment member is configured to be able to
extend above the duct 242 located at the lower limit position. When
the abutment member extends, the duct 242 abuts against the
abutment member, even if the blower 241 operates, and the duct 242
is restricted from rising. On the other hand, in the method of
using a solenoid, a plunger of the solenoid is connected to the
duct 242. When the solenoid is pulled, the duct 242 connected to
the plunger is restricted from rising, even if the blower 241
operates. Thus, the operation of the lock mechanism 246 restricts
the duct 242 at the lower limit position, even if the blower 241
operates (FIG. 4C). The operation of the lock mechanism 246 is
controlled by the control unit 250.
[0052] As described above, the height of the blowing port 243
connected to the duct 242 is adjusted in response to rising and
lowering of the duct 242. When the duct 242 is located at the upper
limit position, that is, when the pressure of air is applied
according to the operation of the blower 241, the blowing port 243
is positioned at a preset normal blowing position (FIG. 4B). In the
normal blowing position, only a lower side area of the blowing port
243 faces a side surface of the stack of paper sheets, and an upper
side area of the blowing port 243 protrudes upward above the
uppermost paper sheet P. In contrast, when the duct 242 is located
at the lower limit position, that is, when the blower 241 is not in
operation, or when the lock mechanism 246 is operated even though
the blower 241 operates, the blowing port 243 is set to a position
lower than the normal blowing position. At this position,
substantially the entire area of the blowing port 243 faces the
side surface of the stack of paper sheets.
[0053] Adjusting the height of the blowing port 243 enables
adjustment of an area of the blowing port 243 facing the side
surface of the stack of paper sheets. In a case where the area of
the blowing port 243 facing the side surface of the stack of paper
sheets is smaller, a ratio of air blown to the side surface of the
stack of paper sheets to air output from the blowing port 243
decreases. In contrast, in a case where the area of the blowing
port 243 facing the side surface of the stack of paper sheets is
larger, the ratio of air blown to the side surface of the stack of
paper sheets to air blown from the blowing port 243 increases. In
other words, adjusting the height of the blowing port 243 enables
adjustment of the ratio of air blown to the side surface of the
stack of paper sheets.
[0054] The control unit 250 controls operation of the large
capacity paper feeder 200. As the control unit 250, a microcomputer
mainly including a CPU, a ROM, a RAM, and an I/O interface is
usable. The CPU executes various programs to control the operation
of the large capacity paper feeder 200 (processor). The ROM stores
various programs executed by the CPU, in the form of program codes
readable by the CPU. The ROM also stores data necessary for
execution of the programs. The RAM is a memory serving as a storage
area for work. The programs and data stored in the ROM are loaded
into the RAM when read by the CPU. Then, the CPU performs various
processing on the basis of the programs and data loaded into the
RAM.
[0055] In the present embodiment, the control unit 250 performs a
sheet feeding operation of feeding a paper sheet P (uppermost paper
sheet P) from the stack of paper sheets. Specifically, the control
unit 250 controls the suction portion 226 to suck a paper sheet P
(uppermost paper sheet P) from the stack of paper sheets loaded on
the paper table 211 (suction control). At this time, the control
unit 250 controls the side end blowing portions 240 to blow air for
floating the paper sheet P (blowing control). Next, when the
control unit 250 determines, via the suction sensor, that the paper
sheet P has been sucked, the control unit 250 finishes the blowing
control. Then, the control unit 250 controls the leading end
blowing portion 230 to blow air from the leading end side of the
paper sheet P, fanning the uppermost paper sheet P and the second
and subsequent sheets P (fanning control). Similarly, the control
unit 250 controls the sheet transport portion 221 to feed the paper
sheet P forward to the transport path (transport control). When the
paper sheet P is fed to the transport path, the control unit 250
finishes the fanning control and transport control. This series
sheet feeding operation is repeated for a new uppermost paper sheet
P each time the paper sheet P is fed.
[0056] The outline of the blowing control which is one of the
features of the present embodiment will be described. In the
following description, a side end blowing portion 240 facing the
right side of a stack of paper sheets is referred to as a side end
blowing portion 240 on the right side, and a side end blowing
portion 240 facing the left side of the stack of paper sheets is
referred to as a side end blowing portion 240 on the left side
(elements constituting each side end blowing portion 240 are
similarly expressed).
[0057] The control unit 250 includes a plurality of operation modes
to perform the blowing control. The control unit 250 basically
performs blowing control in a normal operation mode.
[0058] FIG. 5 is an explanatory diagram of the normal operation
mode. In the normal operation mode, the side end blowing portions
240 on the right and left sides are operated under the same
conditions. Specifically, in the normal operation mode, the height
of a blowing port 243 on the left side and the height of a blowing
port 243 on the right side are aligned at the normal blowing
position. In addition, the height of a sheet holder 244 on the left
side and the height of a sheet holder 244 on the right side are
aligned. Furthermore, the amount of air blown from the blowing port
243 on the left side is equal to the amount of air blown from the
blowing port 243 on the right side.
[0059] While, when determining a predetermined switching condition,
the control unit 250 switches the normal operation mode to a
floating priority mode in which the right side or left side of a
paper sheet P is positively floated. The floating priority mode is
achieved in one of a first operation mode, a second operation mode,
and a third operation mode, which will be described later or in a
combined mode of two or more thereof. In the following description,
an example will be described in which a right side end of a paper
sheet P is floated.
[0060] FIG. 6 is an explanatory diagram of the first operation
mode. In the first operation mode, the height of the blowing port
243 on the right side is different from the height of the blowing
port 243 on the left side. Specifically, the height of the blowing
port 243 on the left side is set to a normal blowing position, and
the height of the blowing port 243 on the right side is set to a
position lower than the normal blowing position. In other words,
the height of the blowing port 243 on the right side is lower than
the height of the blowing port 243 on the left side.
[0061] The ratio of air blown to a side surface of the stack of
paper sheets is larger at the blowing port 243 at the lower
position than at the blowing port 243 at the normal blowing
position. Therefore, on the right side surface of the stack of
paper sheets, the amount of air entering between the paper sheets P
increases, and a right end of an uppermost paper sheet P is floated
higher.
[0062] When the right end of the uppermost paper sheet P is floated
higher, the floated area of the paper sheet P approaches the sheet
feed portion 220 and is thus assisted by the suction of the sheet
feed portion 220. Therefore, even when the uppermost paper sheet P
is not entirely floated, the paper sheet P is sucked to the sheet
feed portion 220 from the right end of the paper sheet P.
Therefore, even in a paper sheet P requiring a time to float when
air is uniformly blown from both sides in the normal operation
mode, the floating priority mode (first operation mode) is
applicable, and only the right side or left side of the uppermost
paper sheet P is positively floated, reducing a time required for
floating. Thus, stable sheet feed performance is ensured.
[0063] FIG. 7 is an explanatory diagram of the second operation
mode. In the second operation mode, the height of the sheet holder
244 on the right side is different from the height of the sheet
holder 244 on the left side. Specifically, the height of the sheet
holder 244 on the left side is set lower than the height of the
sheet holder 244 on the right side.
[0064] In this case, at the left end of a paper sheet P, the sheet
holder 244 restricts the paper sheet P from floating. On the other
hand, at the right end of the paper sheet P, there is a sufficient
distance with respect to the sheet holder 244, and the paper sheet
P is allowed to float. When air is blown in this state, the sheet
holder 244 on the left side acts as a fulcrum, and the right end of
the paper sheet P is floated higher.
[0065] When the right end of the paper sheet P is floated higher,
the floated area of the paper sheet P approaches the sheet feed
portion 220 and is thus assisted by the suction of the sheet feed
portion 220. Therefore, even when the paper sheet P is not entirely
floated, the paper sheet P is sucked to the sheet feed portion 220
from the right end of the paper sheet P. Therefore, even in a paper
sheet P requiring a time to float when air is uniformly blown from
both sides in the normal operation mode, the floating priority mode
(second operation mode) is applicable, and only the right side or
left side of the uppermost paper sheet P is positively floated,
reducing a time required for floating. Thus, stable sheet feed
performance is ensured.
[0066] FIG. 8 is an explanatory diagram of the third operation
mode. In the third operation mode, the amount of air blown from the
blowing port 243 on the right side is different from the amount of
air blown from the blowing port 243 on the left side. Specifically,
the amount of air blown from the blowing port 243 on the right side
is increased. In this case, the ratio of air blown to a side
surface of the stack of paper sheets from the blowing port 243 on
the right side is increased. Thus, at the right end of the stack of
paper sheets, the amount of air entering between paper sheets P
increases, and the floating amount increases.
[0067] When the right end of the uppermost paper sheet P is floated
higher, the floated area of the paper sheet P approaches the sheet
feed portion 220 and is thus assisted by the suction of the sheet
feed portion 220. Therefore, even when the uppermost paper sheet P
is not entirely floated, the paper sheet P is sucked to the sheet
feed portion 220 from the right end of the paper sheet P.
Therefore, even in a paper sheet P requiring a time to float when
air is uniformly blown from both sides in the normal operation
mode, the floating priority mode (third operation mode) is
applicable, and only the right side or left side of the uppermost
paper sheet P is positively floated, reducing a time required for
floating. Thus, stable sheet feed performance is ensured.
[0068] Note that in a case where the first operation mode and the
third operation mode are combined, the height of a blowing port 243
blowing a larger amount of air is preferably set lower than the
height of a blowing port 243 blowing a smaller amount of air.
Similarly, when combining the second operation mode and the third
operation mode, the height of a sheet holder 244 positioned on a
side where a smaller amount of air is blown is preferably set lower
than a sheet holder 244 positioned on a side where a larger amount
of air is blown.
[0069] Switching between the normal operation mode and the floating
priority mode is performed on the basis of one or both of the
information on the paper sheet P and a floating state of the paper
sheet P. The information on the paper sheet P represents the basis
weight and length of the paper sheet. In a case of a paper sheet P
having a large basis weight or a paper sheet P having a large
length, it may take time to float even if air is blown in the
normal operation mode. Therefore, the control unit 250 is
configured to determine to switch operation modes in accordance
with the information on the paper sheet P. Thus, a time required
for floating can be reduced, and stable sheet feed performance can
be ensured. Furthermore, the control unit 250 is configured to
monitor an actual floating state of the paper sheet P to switch
operation modes according to the paper sheet P requiring a time for
floating. Thus, a time required for floating can be reduced, and
stable sheet feed performance can be ensured.
[0070] Hereinafter, the operation of the image forming system
according to the present embodiment, specifically, a sheet feeding
process for paper sheets P in the large capacity paper feeder 200
will be described. Here, FIG. 9 is a flowchart illustrating the
sheet feeding process. The process illustrated in this flowchart is
performed by the control unit 250 with a sheet feed job as a
trigger.
[0071] Firstly, in step S10, the control unit 250 performs initial
setting of an operation mode. In the initial setting, the control
unit 250 reads information on a paper sheet P to be fed. Then, the
control unit 250 determines an operation mode on the basis of a
table (see FIG. 10) in which relationships between the operation
modes and information (basis weights and lengths of sheets) on
paper sheets P are defined.
[0072] In step S11, the control unit 250 performs a sheet feeding
operation for an uppermost paper sheet P of a stack of paper
sheets. Specifically, the control unit 250 performs suction
control, blowing control, fanning control, and transport control.
In this case, the blowing control is performed in the operation
mode determined in step S10.
[0073] In step S12, the control unit 250 calculates a period of
time from starting of the sheet feeding operation, that is, from
floating of the paper sheet P to detection of the paper sheet P by
the suction sensor, namely, a floating time T.
[0074] In step S13, the control unit 250 determines whether the
floating time T is equal to or larger than a first threshold value
T1. The first threshold value T1 is a threshold value for
determining a floating state requiring a longer time than a normal
floating time and has an optimum value set on the basis of
experiments or simulations. Where the floating time T is equal to
or larger than the first threshold value T1, an affirmative
determination is made in step S13, and the process proceeds to step
S14. On the other hand, when the floating time T is smaller than
the first threshold value T1, a negative determination is made in
step S13, and the process proceeds to step S15.
[0075] In step S14, the control unit 250 switches the operation
mode to a floating priority mode. In addition, prior to step S14,
in a case where the operation mode has already been switched to a
floating priority mode, the floating priority mode is continued. In
this case, if there is an operation mode of the floating priority
mode not yet performed, the operation mode may be added. For
example, when only the first operation mode has been performed, one
or both of the second operation mode and the third operation mode
may be added.
[0076] In step S15, the control unit 250 determines whether the
floating time T is smaller than a second threshold value T2. The
second threshold value T2 is a threshold value for determining a
floating state requiring a shorter time than a normal floating time
and has an optimum value set on the basis of experiments or
simulations. When the floating time T is smaller than the second
threshold value T2, an affirmative determination is made in step
S15, and the process proceeds to step S16. On the other hand, when
the floating time T is equal to or larger than the second threshold
value T2, a negative determination is made in step S15, and the
process proceeds to step S17.
[0077] In step S16, the control unit 250 switches the operation
mode to the normal operation mode. When the current floating
priority mode has been performed in a plurality of operation modes,
the floating priority mode may be continued in a reduced number of
operation modes instead of immediately switching to the normal
operation mode. For example, in a case where the floating priority
mode is performed by combining the first operation mode, the second
operation mode, and the third operation mode, one or two of the
operation modes are stopped.
[0078] In step S17, the control unit 250 determines whether the
sheet feed job is finished. When the sheet feed job is finished, an
affirmative determination is made in step S17, and the present
routine is finished. On the other hand, when the sheet feed job is
not finished, a negative determination is made in step S17, and the
process returns to step S11.
[0079] As described above, in the present embodiment, the large
capacity paper feeder 200 performs blowing control of blowing air
for floating a paper sheet P in one of the first operation mode in
which the height of one blowing port 243 is different from the
height of another blowing port 243, the second operation mode in
which the height of the sheet holder 244 corresponding to one side
surface of a stack of paper sheets is different from the height of
the sheet holder 244 corresponding to another side surface of the
stack of paper sheets, and the third operation mode in which the
amount of air blown from the one blowing port 243 is different from
the amount of air blown from the other blowing port 243 or in a
combined mode of two or more of the first to third operation
modes.
[0080] According to this configuration, the right side or left side
of the paper sheet P can be floated higher. Thus, the floated area
of the paper sheet P approaches the sheet feed portion 220 and is
thus assisted by the suction of the sheet feed portion 220.
Therefore, even when the paper sheet P is not entirely floated, the
paper sheet P is sucked to the sheet feed portion 220 from the
right end of the paper sheet P. Therefore, even in a paper sheet P
requiring a time to float when air is uniformly blown from both
sides in the normal operation mode, the floating priority mode is
applicable, and only the right side or left side of the uppermost
paper sheet P is positively floated, reducing a time required for
floating. Thus, stable sheet feed performance is ensured.
[0081] In the present embodiment, the sheet holders 244 are
disposed to both side surfaces of the stack of paper sheets.
However, as illustrated in FIG. 11, a single sheet holder 244
disposed so as to extend from one side surface of the stack of
paper sheets to another side surface may be used.
[0082] Furthermore, in the present embodiment, since adjustment of
the height of each blowing port 243 and adjustment of the height of
each sheet holder 244 are separately performed, the movable
mechanisms 245 are each provided to move the sheet holder 244.
However, the sheet holder 244 may be provided at an upper portion
of the blowing port 243 so as to be turned by air output from the
blowing port 243, and the height of the sheet holder 244 is
adjusted according to the elevation of the duct 242.
[0083] Furthermore, in the present embodiment, the configuration to
move the duct 242 in response to the pressure of air from the
blower 241 and the configuration to restrict this movement by using
the lock mechanism 246 adjust the height of the blowing port 243.
However, whole or part of the side end blowing portion 240 may be
configured to be moved by an electrically-driven lift mechanism.
Furthermore, in the present embodiment, the height of the blowing
port 243 is adjusted in two stages, that is, the normal blowing
position and the lowest position. However, the height of the
blowing port 243 may be adjusted in multiple stages or in a
stepless manner between the normal blowing position and the lowest
position.
[0084] Although the image forming system according to the
embodiments of the present invention has been described, the
present invention is not limited to the above-mentioned
embodiments, and it is apparent that various modifications and
alterations may be made without departing from the scope and spirit
of the invention. Furthermore, not only the image forming system
but also the paper feeder (large capacity paper feeder) itself
constituting the image forming system functions as part of the
present invention. Still furthermore, the present invention may be
applied to the paper feed unit incorporated in the image forming
apparatus, and in this case, the image forming apparatus can also
function as part of the present invention.
[0085] In a case where an image forming system includes an image
forming apparatus and a paper feeder, the image forming apparatus
and the paper feeder may separately include a control function or
the image forming apparatus and the paper feeder may share one
control function in which the respective control functions are
integrated. The separate control functions and the single control
function both serve as a control unit for controlling the image
forming apparatus and the paper feeder.
[0086] Although embodiments of the present invention have been
described and illustrated in detail, the disclosed embodiments are
made for purposes of illustration and example only and not
limitation. The scope of the present invention should be
interpreted by terms of the appended claims.
* * * * *