U.S. patent application number 10/914265 was filed with the patent office on 2005-02-24 for sheet feeding apparatus and image forming apparatus.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Isemura, Keizo.
Application Number | 20050040584 10/914265 |
Document ID | / |
Family ID | 34190082 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050040584 |
Kind Code |
A1 |
Isemura, Keizo |
February 24, 2005 |
Sheet feeding apparatus and image forming apparatus
Abstract
A sheet feeding apparatus includes a sheet supporting unit which
supports a plurality of sheets, a sheet feeding unit which feeds
the sheet one by one from a stack of sheets supported by the sheet
supporting unit, an air blowing unit which blows air to an end
portion of the stack of sheets supported by the sheet supporting
unit, the air blowing unit being able to change wind velocity of
the blown air, a material setting unit which sets arbitrarily and
registers the wind velocity of the air blown by the air blowing
unit in accordance with a type of the sheet, and a sheet feeding
control unit which controls the wind velocity of the air blown by
the air blowing unit based on data registered by the material
setting unit.
Inventors: |
Isemura, Keizo; (Tokyo,
JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON KABUSHIKI KAISHA
TOKYO
JP
|
Family ID: |
34190082 |
Appl. No.: |
10/914265 |
Filed: |
August 10, 2004 |
Current U.S.
Class: |
271/97 ;
271/98 |
Current CPC
Class: |
B65H 2220/01 20130101;
B65H 2513/10 20130101; B65H 2701/10 20130101; B65H 2220/02
20130101; B65H 2513/10 20130101; B65H 3/48 20130101 |
Class at
Publication: |
271/097 ;
271/098 |
International
Class: |
B65H 003/14; B65H
005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2003 |
JP |
2003-207885 |
Claims
What is claimed is:
1. A sheet feeding apparatus comprising: sheet supporting means for
supporting a plurality of sheets; sheet feeding means for feeding
the sheet one by one from a stack of sheets supported by said sheet
supporting means; air blowing means for blowing air to an end
portion of the stack of sheets supported by said sheet supporting
means, said air blowing means being able to change wind velocity of
the blown air; material setting means for setting arbitrarily and
registering the wind velocity of the air blown by said air blowing
means in accordance with a type of the sheet; and sheet feeding
control means for controlling the wind velocity of the air blown by
said air blowing means based on data registered by said material
setting means.
2. A sheet feeding apparatus comprising: sheet supporting means for
supporting a plurality of sheets; sheet feeding means for feeding
the sheet one by one from a stack of sheets supported by said sheet
supporting means; air blowing means for blowing air to a side
surface of the stack of sheets supported by said sheet supporting
means, said air blowing means being able to change wind velocity of
the blown air; material setting means for setting arbitrarily and
registering the wind direction of the air blown by said air blowing
means in accordance with a type of the sheet; and sheet feeding
control means for controlling the wind direction of the air blown
by said air blowing means based on data registered by said material
setting means.
3. A sheet feeding apparatus according to claim 1, further
comprising material fine adjustment setting means for setting and
registering fine adjustment of the wind velocity of the air in
accordance with the type of the sheet, and said sheet feeding
control means controls the wind velocity of the air blown by said
air blowing means based on a setting value registered by said sheet
feeding control and said material fine adjustment setting
means.
4. A sheet feeding apparatus according to claim 2, wherein said air
blowing means is configured to be able to swing in a vertical
direction, and said material setting means sets and registers
ON/OFF of a swing of said air blowing means and changes a wind
direction of the air by performing ON/OFF of the swing of said air
blowing means based on the setting by said material setting
means.
5. A sheet feeding apparatus according to claims 1 or 2, further
comprising environmental measurement means for measuring
environment near said sheet supporting means, and said sheet
feeding control means performs control based on the setting of said
material setting means and measurement result of said environmental
measurement means.
6. A sheet feeding apparatus according to claims 1 or 2, wherein
said material setting means comprises a material storage table in
which initial data is stored in each material, said material
setting means controlling the air blowing of said air blowing means
based on the initial data of the material storage table when the
registration is not performed by said material setting means.
7. A sheet feeding apparatus according to claims 1 or 2, wherein
said material setting means comprises a material storage table
which stores data registered in each material, the initial data
suitable to each material is stored in the material storage table,
and said material setting means controls the air blowing of said
air blowing means based on the initial data of the material storage
table when the registration is not performed by said material
setting means.
8. A sheet feeding apparatus according to claims 1 or 2, wherein
said sheet feeding means comprises suction belt which sucks the
uppermost sheet of the sheets supported by said sheet supporting
means, said material setting means can set arbitrarily and register
strength of suction force of the suction belt, and said sheet
feeding control means controls the suction force based on the data
registered by said material setting means.
9. A sheet feeding apparatus comprising: a paper deck which
supports a plurality of sheets; a suction belt which is arranged
above said paper deck, said paper deck sucking and feeding the
uppermost sheet; an air blowing duct which is provided in front of
a stack of sheets supported by said paper deck; a blowing fan which
supplies air to said air blowing duct; material setting means for
setting arbitrarily and registering the wind velocity of the air
blown by said air blowing means in accordance with a type of the
sheet; and sheet feeding control means for controlling the wind
velocity of the air blown by said air blowing means based on data
registered by said material setting means.
10. A sheet feeding apparatus according to claim 9, wherein said
air blowing duct comprises a shutter which can swing in a vertical
direction, and said material setting means sets and registers
ON/OFF of a swing of the shutter and changes a wind direction of
the air by performing ON/OFF of the swing of the shutter based on
the setting by said material setting means.
11. A sheet feeding apparatus according to claim 9, wherein said
air blowing duct comprises a swing nozzle which can swing in the
vertical direction, and said material setting means sets and
registers ON/OFF of the swing of the swing nozzle and changes the
wind direction of the air by performing ON/OFF of the swing of the
swing nozzle based on the setting by said material setting
means.
12. A sheet feeding apparatus comprising: a sheet feeding apparatus
according to any one of claims 1 to 11; and an image forming
portion which forms an image fed by the sheet feeding apparatus.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a sheet feeding apparatus
which separates and feeds a sheet one by one from a stack of sheets
stacked in a sheet storage portion.
[0003] 2. Related Background Art
[0004] In an image forming apparatus such as a copying machine and
a printer, continuously feedable cut sheet has been generally
limited to high-quality paper or standard paper specified by a copy
machine manufacturer. In such paper, evenness of its surface is low
and air permeability is also low, so that air easily flows into
between the sheets. When the sheet is drawn one by one from the
stacked sheets, there is a low possibility that the sheets are
attracted on each other to generate double feeding.
[0005] Recently, as recording medium becomes diversified, demand of
the image formation is increased even for the sheet having the even
surface such as art paper and coated paper in addition to thick
paper, an OHP sheet, tracing paper, and the like. In the art paper
and coated paper, coating treatment is applied to the surface of
the sheet in order to enhance gloss and whiteness from marketing
needs of colorization. However, since the OHP sheet, the tracing
paper, the art paper, and the coated paper have the higher evenness
and air permeability, particularly when the sheets are stacked
under environment of high humidity, the sheets are attracted on
each other. Therefore, in the friction separation method generally
used in the conventional copying machine and printer, there has
been generated a problem that the double feeding or miss feed often
occurs.
[0006] On the other hand, an air sheet supply method, in which the
sheet is raveled-out by blowing air from a side surface of the
stack of sheets and the sheet is simultaneously separated and fed
one by one from the upper most sheet with a suction apparatus and a
conveying belt which are arranged above the stack of sheets, is
adopted in a few of copying machines and in a printing industry.
When compared with the friction separation method, the air sheet
supply method has the following merits. That is, 1) setting
latitude of a sheet supply condition is broad for a material (type
of sheet), 2) the air sheet feeding method is adaptable to
high-speed sheet feeding, 3) high durability, and 4) low running
cost.
[0007] There have been made many proposals concerning the air sheet
supply method. The proposal disclosed in Japanese Patent
Application Laid-Open No. S62-249835 can be cited as an example. As
shown in FIG. 17, Japanese Patent Application Laid-Open No.
S62-249835 proposes the method in which, in a sheet feeding
apparatus 1, the air is blown with an air blower device 7 from a
direction parallel to the upper surface of the sheet to the side
surface at a front end of sheets S stacked on a sheet supply stage
3, and negative pressure is generated in a suction pipe 11 opened
at an upper side of the sheet by a negative pressure generation
device 9 to suck the sheet. The sheet feeding apparatus 1 is
intended to surely separate the uppermost sheet from the next
sheet, such that the uppermost sheet is floated from the sheets S
stacked on the sheet supply stage 3 by the sucking operation from
the opening to blow the air from the air blower device 7 into a gap
formed between the uppermost sheet and the next sheet.
[0008] As shown in FIG. 18, Japanese Patent Application Laid-Open
No. H11-005643 discloses a sheet feeding apparatus 21 including a
sheet supply tray 23 stacking the sheets S, sheet supplying means
(not shown) for feeding the sheet from the sheet supply tray 23,
air blowing means 27 for blowing the air from the direction
perpendicular to the side surface of the sheets to the side surface
and upper surface of the stacked sheets, and flow path moving means
30 for moving a flow path of the air blown from the air blowing
means 27 in the direction perpendicular to the sheet surface.
[0009] The flow path moving means 30 includes a guide rail (not
shown) which supports the air blowing means 27 while being able to
move the air blowing means 27 in the perpendicular direction, an
electric motor 32, and a cam plate 34 which is fixed to an output
shaft of the electric motor 32 and moves the air blowing means 27
while sliding on a lower surface of the air blowing means 27. When
the cam plate 34 is rotated by rotating the electric motor 32, the
whole of air blowing means 27 is moved in the perpendicular
direction. In the sheet feeding apparatus 21, an opening portion
(air blowing outlet) of the air blowing means 27 always has a
constant opening area, so that the air is moved in the direction
perpendicular to the sheet surface relative to the side surface of
the sheets S by moving the whole of air blowing means 27 in the
perpendicular direction.
[0010] According to the sheet feeding apparatus 21, the flow path
can be moved in the perpendicular direction. Further, however, the
opening portion of the air blowing means 27 always has the constant
opening area in moving the flow path in the perpendicular
direction, the side surface of the sheets S is arranged to be
opposite to the opening portion, which results in formation of an
air narrowing-down portion which reduces the area of the opening
portion to narrow down the air flow blown from the opening portion.
As a result, the sheet feeding apparatus 21 can sequentially float
the sheet from the uppermost sheet of the stacked sheets S to
release the close contact between sheets in all the stacked sheets
S.
[0011] However, as described above, since the OHP sheet, the
tracing paper, the art paper, and the coated paper have the higher
evenness and air permeability, the attraction between the sheets is
generated particularly when the sheets are stacked under the
environment of the high humidity. In the case of the sheet feeding
apparatus 1 adopting the conventional air sheet supply method,
because the air blown to the side surface of the stack of sheets is
the constant flow, the upper portion of the stack of sheets is
floated in the shape of the stack at an interface in which
attraction force is relatively weak. As a result, the air cannot
flow into the gap of the floated stack of sheets, and it is very
difficult to surely separate the sheets one by one.
[0012] In the sheet feeding apparatus 21 which is of another
conventional example including the flow path moving means, although
effect of releasing the attraction between the sheets is obtained
for the relatively thin sheets, the close contact between the
sheets is not released for the relatively thick sheets due to a
heavy weight and a strong body. Therefore, the sheet feeding
apparatus 21 cannot solve the miss feed and the double feeding.
SUMMARY OF THE INVENTION
[0013] In view of the foregoing, it is an object of the invention
to provide the sheet feeding apparatus which realizes the
adaptation to various materials from the thick paper to the thin
paper by user setting and releases surely the attraction between
the sheets with a simple configuration to prevent the generation of
the miss feed or the double feeding, thereby reliability of the
sheet feeding apparatus is intended to be improved.
[0014] The invention is a sheet feeding apparatus including sheet
supporting means for supporting a plurality of sheets, sheet
feeding means for feeding the sheet one by one from a stack of
sheets supported by the sheet supporting means, air blowing means
for blowing air to an end portion of the stack of sheets supported
by the sheet supporting means, the air blowing means being able to
change wind velocity of the blown air, material setting means for
setting arbitrarily and registering the wind velocity of the air
blown by the air blowing means in accordance with a type of the
sheet, and sheet feeding control means for controlling the wind
velocity of the air blown by the air blowing means based on data
registered by the material setting means.
[0015] The invention is a sheet feeding apparatus including a paper
deck which supports a plurality of sheets, a suction belt which is
arranged above the paper deck, the paper deck sucking and feeding
the uppermost sheet, an air blowing duct which is provided in front
of a stack of sheets supported by the paper deck, a blowing fan
which supplies air to the air blowing duct, material setting means
for setting arbitrarily and registering the wind velocity of the
air blown by the air blowing means in accordance with a type of the
sheet, and sheet feeding control means for controlling the wind
velocity of the air blown by the air blowing means based on data
registered by the material setting means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a sectional view explaining a first embodiment of
the invention;
[0017] FIGS. 2A, 2B, 2C, and 2D are sectional views showing swing
operation in the first embodiment;
[0018] FIGS. 3A, 3B, 3C, and 3D are explanatory views of an
attraction mechanism of coated paper;
[0019] FIGS. 4A and 4B are explanatory views of attraction
characteristics of the coated paper;
[0020] FIG. 5 is an explanatory view of the swing operation for
thin paper;
[0021] FIGS. 6A and 6B are sectional views explaining the swing
operation for thick paper in the first embodiment;
[0022] FIGS. 7A and 7B are explanatory views of effectiveness of
swing stop for the thick paper;
[0023] FIG. 8 is an explanatory view of a sheet supply separable
area for each type of the coated papers;
[0024] FIG. 9 is a flow chart showing setting registration of a
user material;
[0025] FIG. 10 is a view showing a screen of user material
registration;
[0026] FIG. 11 is a flow chart showing user material fine
adjustment setting registration;
[0027] FIG. 12 is a view showing the screen of material fine
adjustment registration;
[0028] FIG. 13 is a view showing an example of a material storage
table;
[0029] FIG. 14 is a flow chart showing determination of air sheet
feeding conditions;
[0030] FIGS. 15A and 15B are sectional views explaining the swing
operation for the thin paper in a second embodiment;
[0031] FIG. 16 is a sectional view explaining the swing stop for
the thick paper in the second embodiment;
[0032] FIG. 17 is a sectional view showing an example of the
conventional air sheet feeding apparatus; and
[0033] FIG. 18 is a sectional view showing an example of the
conventional air sheet feeding apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Referring to accompanying drawings, preferred embodiments of
the invention will be described below.
[0035] (Overall Configuration)
[0036] FIG. 1 is a sectional view showing a configuration of a main
part of a copying machine according to a first embodiment of the
invention.
[0037] The copying machine includes an image reader 200 which reads
an original image, a printer 300, and a sheet supply portion 400.
The sheet supply portion 400 includes paper decks 401 and 451 which
commonly have a sheet supply mechanism. The paper deck 401 can
store 1,000 sheets and the paper deck 451 can store 1500 sheets.
The sheet supply portion 400 will be described in detail later.
[0038] An original feeding apparatus 100 is mounted on the image
reader 200. The original feeding apparatus 100 sequentially feeds
original D set upward on an original tray 101 from a front end page
one by one toward the left, passes the original D through a flow
read position on an original plate (or a platen glass) 102 from the
left toward the right via a curved path, and then discharges the
original D toward an outside paper discharge tray 112.
[0039] When the original D passes through the flow read position on
the original glass 102 from the left toward the right, the original
image is read with scanner means 104 held at a position
corresponding to the flow read position. This reading method is one
which is generally referred to as an original flow read.
Specifically, when the original D passes through the flow read
position, a read surface of the original D is irradiated with light
of a lamp 103 of the scanner means 104, and the light reflected
from the original D is introduced to a lens 108 through mirrors
105, 106, and 107. The light which has passed through the lens 108
is focused on an image surface of an image sensor 109.
[0040] Original read scan is performed by conveying the original D
so that the original D passes through the flow read point from the
left toward the right. In the original read scan, the direction
orthogonal to a conveying direction of the original D is set to a
main scanning direction, and the conveying direction is set to a
sub-scanning direction. That is, in passing the original D through
the flow read point, the whole of original image is read such that
the original D is conveyed in the sub-scanning direction while the
original image is read one line by one line in the main scanning
direction with the image sensor 109, and the image which has been
optically read is converted into image data with the image sensor
109 and output from the image sensor 109. After predetermined
processing is performed to the image data output from the image
sensor 109 in the later-mentioned image signal control portion 202,
the image data is output as a Video signal to an exposure control
portion 110 of the printer 300.
[0041] It is also possible that the original D is conveyed onto the
original glass 102 with the original feeding apparatus 100 to be
stopped at a position and the original D is read by scanning the
scanner means 104 from the left to the right. This read method is
one referred to as so-called fixed original read.
[0042] When the original D is read without using the original
feeding apparatus 100, a user raises the original feeding apparatus
100 to put the original D on the original glass 102, and then the
original D is read by scanning the scanner means 104 from the left
to the right. That is, when the original is read without using the
original feeding apparatus 100, the fixed original read is
performed.
[0043] The exposure control portion 110 of the printer 300
modulates and outputs a laser beam based on the input video signal.
A photosensitive drum 111 is irradiated with the laser beam while
the laser beam is scanned by a polygon mirror. An electrostatic
latent image is formed on the photosensitive drum 111 in accordance
with the scanned laser beam. At this point, in the fixed original
read, the exposure control portion 110 outputs the laser beam so
that the correct image (not mirror image) is formed.
[0044] The electrostatic latent image on the photosensitive drum
111 is visualized as a developer image by a developer supplied from
a developing device (not shown). The sheet is supplied from the
paper decks 401 and 451 of the sheet supply portion 400 at timing
synchronized with the start of the irradiation of the laser beam.
Then, the sheet is conveyed to between the photosensitive drum 111
and a transfer portion 116 through a resist roller 115. The
developer image formed on the photosensitive drum 111 is
transferred onto the sheet supplied by the transfer portion
116.
[0045] The sheet on which the developer image has been transferred
is conveyed to a fixing portion 117. The fixing portion 117 fixes
the developer image on the sheet by heating the sheet under
pressure. The sheet which has passed through the fixing portion 117
is discharged to a first discharge tray 119 through a first
discharge roller 118 or to a second discharge tray 121 through a
second discharge roller 120 by changing a flapper (not shown).
[0046] (First Embodiment)
[0047] Then, the paper deck of the air sheet supply method
according to the invention will be described in detail.
[0048] The paper deck 401 of the air sheet supply method in a first
embodiment stacks and stores the stack of sheets on an intermediate
plate 403 included in a sheet storage 402. Rails 404 and 405 are
provided on both sides at a lower end portion of the sheet storage
402, and the sheet storage 402 can be drawn from a front side of
the apparatus main body (direction perpendicular to the paper
surface). The stack of sheets stacked and stored in the sheet
storage 402 is fixedly placed at a position by a pre-separation
plate 406 at a front end portion of the stack of sheets, a rear end
regulation plate (not shown) at a rear end portion, and a side
regulation plate (not shown) at a side portion.
[0049] An environmental measurement sensor 460 as environmental
measurement means for measuring the environment such as temperature
and humidity inside the sheet supply portion is arranged in the
sheet supply portion 400. Further, a control portion C as the
later-mentioned sheet feeding control means for control the
separation and feed of the sheet is also arranged in the sheet
supply portion 400.
[0050] FIGS. 2A to 2D is a schematic sectional view of the main
part of the sheet supply portion 400. The sheet supply portion 400
includes a suction duct 408 above the stack of sheets stacked on
the intermediate plate 403. The suction duct 408 is connected to a
suction fan F1 to be able to generate suction static pressure above
the stack of sheets. A suction belt 407, which has a multiplicity
of holes so that the holes surround the suction duct 408, is
arranged while being able to be rotated in the sheet supply
direction (arrow direction in FIG. 2D).
[0051] A blowing fan F2 and a blowing duct 413 as air blowing means
of the invention are provided on the front side in the sheet
feeding direction of the paper deck 401. The blowing duct 413 is
connected to the blowing fan F2 and provided with an opening 414
opened toward the side surface at the front end of the stack of
sheets stacked and stored in the sheet storage 402. The blowing fan
F2 supplies the air to the blowing duct 413. A heater 422 is
arranged between the blowing fan F2 and the blowing duct 413. The
heater 422 heats the blowing air to improve raveling-out properties
of the sheet. For the temperature of the blowing air, the optimum
temperature according to the material has been found by experiments
and the like. The temperature of the blowing air can be adjusted by
controlling the heater 422.
[0052] The sheet supply portion 400 also includes a shutter 415
which can be moved in the substantially vertical direction between
the side surface of the stack of sheets and the opening 414. A part
of the shutter 415 includes a slit 416 whose width is sufficiently
smaller than that of the opening 414. Detection means 417 for
detecting a phase of the moving shutter 415 is provided in the
sheet supply portion 400. Alternatively, it is also possible to use
the plurality of fans to perform ON/OFF control without providing
the shutter mechanism. The sheets in the upper portion of the stack
of sheets are raveled-out by the air blown from the opening
414.
[0053] A separation air blowing nozzle 420 for blowing the air
along the lower surface of the suction belt 407 is arranged in the
upper portion of the blowing duct 413.
[0054] In sheet separating and feeding operation, as shown in FIGS.
2A to 2D, the raveling-out, the floatation, and the separation of
the sheet are performed by blowing the air from the side end of the
stack of sheets while the shutter 415 is vertically moved, and the
sheets except for the uppermost sheet are surely separated from one
another. The uppermost sheet is sucked to the suction belt 407 by
the air from the separation air blowing nozzle 420.
[0055] Then, the attraction mechanism will be clarified for the
coated paper, in which the attraction phenomenon is generated under
high humidity and the problems such as the miss feed and the double
feeding can not be avoided in the conventional sheet supply
method.
[0056] As shown in FIG. 3A, when the stack of sheets of the coated
paper is exposed under the high-humidity environment, the surface
of the uppermost sheet and the end portions of the stacked sheets
absorb moisture. Then, as shown in FIG. 3B, the uppermost sheet is
expanded and peripheries of the sheets subsequent the uppermost
sheet are swelled. At this point, because the expansion is smaller
in a backside of the uppermost sheet, a convex deformation
phenomenon is generated as shown in FIG. 3C. Because the coated
paper has the high evenness and the low air permeability, the air
flow into between the sheets is not substantially generated.
Therefore, as shown in FIG. 3C, when the uppermost sheet of the
coated paper is expanded to generate the convex deformation, there
is generated the phenomenon (attraction by moisture-absorption of
the uppermost sheet), in which a volume between the sheets is
expanded and the negative pressure is generated to cause the
attraction. The moisture absorption proceeds from the peripheries
and the peripheries are swelled in the stack of sheets except for
the uppermost sheet.
[0057] Since an area near the central portion is not swelled, there
is generated the phenomenon (attraction by moisture-absorption of
the paper peripheries), in which volume expansion occurs in the
direction of a sheet thickness and the negative pressure is
generated to cause the attraction. As shown in FIG. 3D, sometimes
the convex deformation is also generated in the second sheet by
affection of the convex deformation of the uppermost sheet and the
negative pressure is generated between the second sheet and the
third sheet to cause the attraction. Sometimes this phenomenon
extends from the third sheet to tens of sheets. The phenomenon is
referred to as chain deformation. As described above, the mechanism
of the coated paper attraction under the high humidity includes
three types of the attraction phenomena. The three types of the
attraction phenomena have the characteristics shown in FIGS. 4A and
4B.
[0058] As shown in FIG. 4A, since the negative pressure by the
convex deformation of the uppermost sheet is generated by absorbing
the moisture from the overall surface of the sheet, a scale of the
negative pressure by the convex deformation becomes much larger
than that of the negative pressure by the swelling of the
peripheries of the sheet. That is, moisture-absorption and
attraction force of the uppermost sheet is much larger than
moisture-absorption and attraction force of the paper peripheries.
As shown in FIG. 4B, in relatively thin OK coated paper L; 72
g/m.sup.2, the chain deformation is easy to generate due to weak
paper body, and the chain deformation is generated up to about 40
sheets. On the contrary, in relatively thick double-side coated
card paper; 317 g/m.sup.2, it is found that the convex deformation
by the negative pressure of the paper hardly overcomes against the
paper body and the chain deformation attraction is not
substantially generated.
[0059] Therefore, in the sheet feeding apparatus which is disclosed
in Japanese Patent Application Laid-Open No. 11-005643 and includes
the conventional flow path moving means, the sheet feeding
apparatus only has constant moving means irrespective of difference
in the attraction phenomena by the above-described material (type
of sheet), so that the sheet feeding apparatus is not sufficient
for the release of the close contact between the sheets and the
sheet feeding apparatus can not solve the miss feed and the double
feeding.
[0060] The operation of the invention, which is based on the
clarified attraction mechanism of the coated paper, will be
described in detail below. At first the case of the thin paper
supply will be described. As shown in FIGS. 2A to 2D, when the thin
coated paper (for example, OK royal coated paper; 64 g/m.sup.2) is
set on the paper deck 401 to insert the paper into the main body,
the intermediate plate 403 is lifted by a lift-up motor (not shown)
to be positioned at a predetermined height with sheet height
detection means (not shown). Then, the sheet supply operation is
started by pressing a copy button.
[0061] While the suction fan F1 above the stack of sheets starts
the sucking operation, the blowing fan F2 is operated to blow the
air to the side surface of the stack of sheets. At this point, as
shown in FIGS. 2A to 2D, the shutter 415 is vertically reciprocated
(hereinafter, referred to as swing operation) between the side
surface of the stack of sheets and the opening 414 of the blowing
duct 413 by transferring drive from a drive source (not shown).
Since the slit 416 whose width is sufficiently narrower than that
of the opening 414 is formed in the shutter 415, when the slit 416
reaches the opening 414, the wind velocity of the air passing
through the slit 416 is increased because of the difference in the
widths and the strong air can be blown.
[0062] When the swing operation of the shutter 415 is performed,
the air which has passed through the slit 416 to have the increased
wind velocity is blown to the side surface of the stack of sheets
while continuously moving upward, so that it is expected that the
sheet feeding apparatus of the invention has the better
raveling-out effect when compared with the conventional steady air
flow. As shown in FIGS. 2A to 2D, FIGS. 3A to 3D, FIGS. 4A to 4B,
and FIG. 5, in the thin coated paper, the attraction can be
effectively released by performing the swing operation for the
uppermost sheet having the strong attraction force and tens of
sheets in the upper portion of the stacked sheets in which the
chain deformation attraction is generated. Therefore, the better
separating and feeding operation can be surely performed one sheet
by one sheet from the uppermost sheet by rotating the suction belt
407.
[0063] In the case of the feeding of the sheet such as the art
paper and the coated paper in which the attraction phenomenon is
easily occurs under the high humidity, it is also possible that
plural-time vertical swing operations of the shutter 415 are
performed as pre-operation of the sheet feeding.
[0064] Then, the feeding operation of the thick coated paper will
be described. As shown in FIG. 6A, in the case of the sheet feeding
of the thick paper (for example, double-side coated card paper; 317
g/m.sup.2), the slit 416 of the shutter 415 is fixed at a position
including a sheet-supply sheet-surface height, i.e., the swing
operation is stopped. The positional detection can be performed by
the detection means 417 and a flag portion 418 formed in the
shutter 415.
[0065] Sometimes the separation effect is also lost when the swing
operation is performed in the thick coated paper. As shown in FIG.
7A, when the swing operation is performed in the thick coated
paper, the little chain deformation attraction is generated without
releasing the attraction of the uppermost sheet in which the strong
attraction is generated, so that the separation and floatation are
generated in the attraction portion in the peripheries of the paper
where the attraction is weak. Further, there is also a demerit that
decreases the time when the strong air is blown to between the
uppermost sheet and the subsequent sheet where the strongest
attraction is generated. Therefore, as shown in FIGS. 6B and 7B, it
is effective that the swing operation is stopped and the strong air
is continuously blown to between the uppermost sheet and the
subsequent sheet, where the attraction is strong, with pinpoint
accuracy.
[0066] Based on the above-described attraction mechanism of the
coated paper, the chain deformation attraction can be released by
the swing operation for the thin coated paper, and the
moisture-absorption and attraction of the uppermost sheet can be
released by stopping the swing operation for the thick coated
paper. FIG. 8 shows sheet supply separable area maps for various
sheets of the coated paper as experimental results. The
experimental results in FIG. 8 show that the swing operation is
preferable only to the sheet not more than 105 g/m.sup.2 and the
swing stop is preferable to the sheet more than 105 g/m.sup.2.
Material setting means in which the optimum separating and feeding
conditions are set and registered in accordance with the material
(type of sheet) by the user will be described referring to a flow
chart shown in FIG. 9 and an operation screen shown in FIG. 10.
[0067] The suction force of the suction belt 407 by the suction
duct 408 can be adjusted by controlling the number of revolutions
of the suction fan F1 to change the amount of suction. The wind
velocity of the raveling-out air (the mount of raveling-out air)
passing through the opening 414 of the blowing duct 413 can be
adjusted by controlling the number of revolutions of the blowing
fan F2. At this point, the amount of air suction of the suction fan
F1 for generating the suction force in the suction belt 407 is
referred to as the amount of separation air, and the amount of air
blow which is blown from the opening 414 of the blowing duct 413 is
referred to as the amount of raveling-out air.
[0068] In the user material registration (Step 1301) of the
registration flow shown in FIG. 9, the user sets and registers a
name of the material, and the amount of separation air, the amount
of raveling-out air, the air temperature, and ON/OFF of the swing
operation in accordance with the material on the operation screen
shown in FIG. 10. When a registration button is pressed after the
setting, the name of the material, the amount of separation air,
the amount of raveling-out air, the air temperature, and ON/OFF of
the swing operation are stored in a storage table shown in FIG. 13
(Step 1302). In this case, although the name of the material, the
amount of separation air, the amount of raveling-out air, the air
temperature, and ON/OFF of the swing operation can be cited as
examples of setting items, the number of fans used and the like may
be added as the setting item.
[0069] In the storage table of FIG. 13, initial values of the
amount of separation air, the amount of raveling-out air, the air
temperature, ON/OFF of the swing operation, the blowing air
temperature, and the number of blowing fans F2 (in the case of the
plurality of fans) in accordance with the material are stored in
each material (data described by "Material-" in FIG. 13). Numeric
characters in FIG. 13 indicate the level of the amount of air. The
numeric character is one in which the difference between the
maximum value and the minimum value is divided into ten equal
parts, assuming that each of the maximum values of the amount of
separation air and the amount of raveling-out air is set to. 10 and
each of the minimum values of the amount of separation air and the
amount of raveling-out air is set to 0.
[0070] In the registration using the material setting means, the
data changed by each user relative to the initial value can be
registered, and the new data for the material in which the initial
value is not set can be also registered.
[0071] In order that the user can perform the further fine
adjustment, user fine adjustment setting means is also included.
The user fine adjustment setting means sets and registers the fine
adjustment of the setting items such as the amount of separation
air, the amount of raveling-out air, the air temperature, and
ON/OFF of the swing operation. The user fine adjustment setting
means will be described below referring to the flow chart shown in
FIG. 11 and a user fine adjustment registration screen shown in
FIG. 12.
[0072] In the flow chart of FIG. 11, the input of the operation
screen shown in FIG. 12 is performed in Step 1401. In this case,
the name of the material stored in the storage table of the name is
called to perform the fine adjustment of the amount of separation
air, the amount of raveling-out air, the air temperature, and
ON/OFF of the swing operation. With reference to a size, it is set
whether the size is considered or not. When the user presses the
registration button, the flow proceeds to Step 1402 to store the
setting items of the fine adjustment in a user fine adjustment
storage table (not shown) as user fine adjustment storage
means.
[0073] The flow to the step in which the actual air sheet supply
conditions are determined will be described referring to FIG.
14.
[0074] In step 1801, it is detected which paper decks 401 or 451 is
selected. In Step 1802, the material set in the paper deck is
detected (the user can set the material). In Step 1803, it is
searched whether the material detected in Step 1802 is registered
in the storage table in the flow of FIG. 9 or not. When the
material is registered in the storage table, the flow proceeds to
Step 1805. When the material is not registered in the storage
table, the flow proceeds to Step 1804.
[0075] In Step 1804, the initial values are read. As shown in FIG.
13, the initial values is drawn from the material storage table in
which the amount of separation air, the amount of raveling-out air,
the air temperature, ON/OFF of the swing operation, the blowing air
temperature, and the number of fans (in the case of the plurality
of fans) the material are stored in each material. In the case
where the material storage table is not included, it is also
possible to prompt the user to set the initial values on the
operation screen shown in FIG. 10. Then, the flow proceeds to Step
1808.
[0076] In Step 1805, the air sheet supply conditions concerning the
registered material are read out from the storage table, and the
flow proceeds to Step 1806. In Step 1806, it is searched whether
the fine adjustment is set by the user or not. When the fine
adjustment is registered, the flow proceeds to Step 1807. When the
fine adjustment is not registered, the flow proceeds to Step 1808.
In Step 1807, the adjustment values are read out from the fine
adjustment item table for the selected material, and the flow
proceeds to Step 1808. In Step 1808, it is searched whether the
environment is considered or not in the air sheet supply condition.
When the environment is set, the flow proceeds to Step 1810. When
the environment is not set, the flow proceeds to Step 1809. In Step
1809, the initial values of the environment setting are read out,
and the flow is ended. In the initial values of the environment
setting, the material storage table in which each value is set in
each material as shown in FIG. 13 can be read out from the storage
table (not shown) previously set.
[0077] In Step 1810, the current environments are measured with the
environmental measurement sensor 460, the conditions suitable to
the environments are read out, and the flow is ended.
[0078] It is also possible that each table such as the material
storage table shown in FIG. 13 is obtained through a network. When
the registration can be performed through the network as well as
the initial conditions, it becomes effective means in the case
where the new material appears on the market.
[0079] While the high-accuracy control is performed by considering
the environmental conditions with the environmental measurement
sensor 460 in the flow chart of FIG. 14, it is also possible to
perform the control of the invention without considering the
environmental conditions by eliminating Steps 1808, 1809, and
1810.
[0080] (Second Embodiment)
[0081] A second embodiment will be described referring to FIGS. 15
and 16. The same component of the second embodiment as that of the
first embodiment is indicated by the same reference numeral, and
the description of the same component will not be repeated here.
Only the portion different from the first embodiment is described,
and the configuration which is not described is same as the first
embodiment.
[0082] The second embodiment includes a swing nozzle 421 as
changing means of the invention for changing the wind direction in
the blowing duct 413 provided on the front side of the stack of
sheets. The swing nozzle 421 can vertically rotate the side end
portion in the upper portion of the stack of sheets.
[0083] In the case of the thin coated paper, similarly to the first
embodiment, the swing nozzle 421 performs the blowing operation to
the sheet lifted up to the position of the sheet-supply
sheet-surface height while continuously moving the air having the
higher wind velocity. As shown in FIGS. 15A and 15B, the swing
nozzle 421 blows the air to the side surface of the stack of sheets
while repeating the swing operations of (a) substantially
horizontal direction and (b) obliquely downward direction.
[0084] Therefore, it is very effective to release the attraction of
the thin coated paper in which the chain deformation attraction is
generated. The air whose wind direction is continuously changed can
be given, so that there is the merit that the separation effect is
extremely increased by blowing the air into the gap between the
sheets attracted to each other or the gap between the sheets
stacked on each other with the sheets slightly shifted from each
other. The number of reciprocating operations and moving aped of
the swing nozzle 421 are registered so as to be arbitrarily set by
the material of the sheet, the size of the sheet, and the
environmental conditions, and the finer adjustment can be performed
by using the fine adjustment storage table in which the fine
adjustment can be performed in each material.
[0085] In the case of the thick coated paper, as shown in FIG. 16,
the swing nozzle 421 is fixed to the position in the substantially
horizontal direction to stop the swing operation, and then the
swing nozzle 421 blows the air to the upper portion of the stack of
sheets. This allows the strong air to be blown for the sufficient
time in order to release the moisture-absorption and attraction of
the uppermost sheet in which the attraction force is the
maximum.
[0086] As described above, even in the embodiment, the swing nozzle
421 having the high raveling-out effect is operated in order to
release the chain deformation attraction in the case of the thin
coated paper, and the swing is stopped to release the attraction of
the uppermost sheet in the case of the thick coated paper. As a
result, the attraction of any coated paper can be released by the
secure inflow of the air between the sheets.
[0087] In the first and second embodiments described above, the air
blow in the sheet supply operation or the presence or absence of
the swing operation can be arbitrarily set by the conditions such
as the material. In order to improve the raveling-out effect, it is
possible to perform the air blow for the predetermined amount of
time before a job or the swing operation. In each embodiment, the
sheet supply method may be any one of a retard roll method,
separation pawl method, a vacuum feed method, and the like. The air
blowing means may adopt either an axial flow method or a sirocco
method or use a compressor device. The air blow direction may be
any one of the side surfaces of the front, rear, left, and right
sides of the stack of sheets.
[0088] This application claims priority from Japanese Patent
Application No. 2003-207885 filed on Aug. 19, 2003, which is hereby
incorporated by reference herein.
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