U.S. patent application number 12/057513 was filed with the patent office on 2008-10-02 for feeding device and image forming apparatus.
Invention is credited to Masaya Asakawa, Masahiko Fujita, Yasuaki Fukada, Norichika Katsura, Masaharu KIMURA, Toyoaki Nanba, Masatsugu Ohishi, Tadasu Taniguchi.
Application Number | 20080237978 12/057513 |
Document ID | / |
Family ID | 39792910 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080237978 |
Kind Code |
A1 |
KIMURA; Masaharu ; et
al. |
October 2, 2008 |
FEEDING DEVICE AND IMAGE FORMING APPARATUS
Abstract
A feeding device according to the present invention holds a pile
of sheets of paper in it. Feed force so acts selectively on a
specified region of the upper side of the held top sheet as to feed
the held sheets one after one in a feed direction. The feeding
device includes a flat press plate and a support. The press plate
is not smaller in the feed direction and the cross directions
perpendicular to the feed direction than the maximum size of the
sheets which can be held in the main body. The press plate is not
larger in the feed and cross directions than the inner size of the
main body. The press plate has a first opening formed over the
specified region. The press plate is supported vertically movably
above the held sheets by the support.
Inventors: |
KIMURA; Masaharu; (Osaka,
JP) ; Taniguchi; Tadasu; (Uda-shi, JP) ;
Fujita; Masahiko; (Nara-shi, JP) ; Katsura;
Norichika; (Tenri-shi, JP) ; Ohishi; Masatsugu;
(Nara-shi, JP) ; Asakawa; Masaya;
(Yamato-Koriyama-shi, JP) ; Fukada; Yasuaki;
(Nara-shi, JP) ; Nanba; Toyoaki; (Osaka,
JP) |
Correspondence
Address: |
MARK D. SARALINO ( SHARP );RENNER, OTTO, BOISSELLE & SKLAR, LLP
1621 EUCLID AVENUE, 19TH FLOOR
CLEVELAND
OH
44115
US
|
Family ID: |
39792910 |
Appl. No.: |
12/057513 |
Filed: |
March 28, 2008 |
Current U.S.
Class: |
271/264 |
Current CPC
Class: |
B65H 1/266 20130101;
B65H 1/14 20130101; B65H 3/46 20130101; B65H 2405/115 20130101 |
Class at
Publication: |
271/264 |
International
Class: |
B65H 5/00 20060101
B65H005/00; B65H 5/36 20060101 B65H005/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2007 |
JP |
2007-088003 |
Claims
1. A feeding device comprising: a main body for holding a pile of
sheets of paper therein; wherein feed force so acts selectively on
a specified region of the upper side of the held top sheet as to
feed the held sheets one after one in a feed direction; a press
plate being shaped like a flat plate being in length in the feed
direction and the cross directions perpendicular to the feed
direction, not smaller than the maximum size of sheets capable of
being held in the main body and not larger than the inner size of
the main body; the press plate having a first opening formed over
the specified region; and a support so supporting the press plate
above the held sheets that the press plate can move vertically.
2. A feeding device as claimed in claim 1, wherein the press plate
can be removed upward from the support.
3. A feeding device as claimed in claim 1, wherein the support is a
rear end guide limiting the upstream movement of the held sheets in
the feed direction.
4. A feeding device as claimed in claim 1, further comprising: a
front end guide for contact with a front corner of the upper side
of the held top sheet on the downstream side in the feed direction;
the press plate having a second opening through which the front end
guide passes vertically.
5. A feeding device as claimed in claim 1, further comprising: a
side edge guide for contact with side edges of the held sheets
parallel in the feed direction; the press plate having a third
opening through which the side edge guide passes vertically.
6. A feeding device as claimed in claim 1, wherein the press plate
includes a flexing portion extending thereacross in the cross
directions, in the middle part of the press plate in the feed
direction.
7. A feeding device as claimed in claim 1, wherein the press plate
is made of a transparent material.
8. An image forming apparatus comprising an image former for
forming an image on a sheet of paper fed from a feeding device as
claimed in claim 1.
Description
CROSS REFERENCE
[0001] This Nonprovisional application claims priority under 35
U.S.C. .sctn. 119 (a) on Patent Application No. 2007-088003 filed
in Japan on Mar. 29, 2007, the entire contents of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] An image forming apparatus or another paper processing
apparatus includes a feeding device, which includes a feed
cassette. The feed cassette holds a pile of sheets of paper. The
paper feeder feeds the held sheets one after one by request. In
general, the paper feeder of a paper processing apparatus feeds
sheets of paper in downward order from a feed cassette.
[0003] Before a feed cassette of a paper processing apparatus holds
sheets of paper, they are wrapped in an airtight material so as to
be low in moisture. If the apparatus is installed in a humid
atmosphere, the sheets held in the feed cassette absorb moisture
and may get too moist. In this case, the top sheet in the feed
cassette, which is most liable to be exposed to the humid
atmosphere, absorbs moisture most quickly, and the lower sheets in
the cassette absorb moisture in downward order.
[0004] As the top sheet gets moist, its surface characteristics
change, so that its frictional resistance decreases. This makes the
top sheet liable to be misfed. This phenomenon occurs remarkably to
coated paper, because SiO.sup.2 or another bleaching component of
the coating on the paper is more hygroscopic than cellulose or
another component of the paper. Coated paper is used often for
color image formation etc.
[0005] A conventional feed cassette of an image forming apparatus
is fitted with a heat source for dehumidifying the sheets in the
cassette in order to prevent them from being misfed by getting
moist. The dehumidification by means of the heat source not only
increases electric power consumption but also makes it difficult to
control calorific power. If the heat source is so activated as to
generate a constant amount of heat, the amount may be excessive,
depending on the number or type of sheets in the feed cassette, the
atmosphere in which the apparatus is installed, and which may vary,
or the like. The excessive amount of heat dries the sheets, so that
they may deform or discolor.
[0006] JP H05-188715 A discloses expandable and contractible covers
each for covering the sheets held in a feed cassette. Each of the
covers is provided to keep foreign substances from entering the
associated cassette and prevent trouble during paper feeding from
the cassette. There is space between each of the covers and the top
sheet in the associated cassette. The space makes it impossible for
some of the covers to keep the associated top sheets from being
exposed to the atmosphere. Accordingly, it is impossible to
reliably keep the sheets from getting moist.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a feed
cassette which prevents the top sheet held in it from being exposed
to the atmosphere even if the number of sheets held in the cassette
changes, and which prevents the sheets from being misfed by getting
moist. Another object of the invention is to provide an image
forming apparatus fitted with such a feed cassette.
[0008] A feed cassette according to the present invention holds a
pile of sheets of paper in it. Feed force so acts selectively on a
specified region of the upper side of the held top sheet as to feed
the held sheets one after one in a feed direction. The feed
cassette includes a flat press plate and a support. The press plate
is not smaller in the feed direction and the cross directions
perpendicular to the feed direction than the maximum size of the
sheets which can be held in the main body. The press plate is not
larger in the feed and cross directions than the inner size of the
main body. The press plate has a first opening formed over the
specified region. The press plate is supported vertically movably
above the held sheets by the support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic sectional front view of an image
forming apparatus according to an embodiment of the present
invention.
[0010] FIG. 2 is a sectional side view of a feed cassette of the
apparatus.
[0011] FIG. 3 is a plan view of the press plate of the feed
cassette.
[0012] FIGS. 4A and 4B are sectional side views of the feed
cassette, showing how a part of the press plate shifts angularly as
the number of sheets held in the cassette changes.
[0013] FIG. 5 is a plan view of the press plate of a feed cassette
according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] With reference to FIG. 1, an image forming apparatus 100
according to an embodiment of the present invention will be
described below in detail. The apparatus 100 consists essentially
of a scanner 200, an image former 300, and a paper feeder 400.
[0015] The scanner 200 includes an automatic document feeder 201, a
first document platform 202, a second document platform 203, a
first mirror base 204, a second mirror base 205, a lens 206, and a
charge coupled device (CCD) 207.
[0016] The document feeder 201 feeds documents one after one from a
document tray 211 via the second document platform 203 to an outlet
tray 212. The document feeder 201 is so supported at its rear edge
as to pivotably cover the upper side of the first document platform
202. A document can be placed manually on the first document
platform 202 by raising the front edge of the document feeder 201
so as to expose the upper side of this platform.
[0017] The document platforms 202 and 203 are a hard glass plate.
The mirror bases 204 and 205 can move horizontally under the
document platforms 202 and 203. The speed at which the second
mirror base 205 moves is 1/2 of the speed at which the first mirror
base 204 moves. The first mirror base 204 carries a light source
and a first mirror. The second mirror base 205 carries a second
mirror and a third mirror.
[0018] The image on a document being fed over the second document
platform 203 by the document feeder 201 is read with the first
mirror base 204 stopping under this platform. The light source on
the first mirror base 204 under the second document platform 203
radiates light to the document passing over this platform. The
light reflected by the document is then reflected by the first
mirror on the first mirror base 204 toward the second mirror base
205.
[0019] The image on a document placed on the first document
platform 202 is read with the mirror bases 204 and 205 moving
horizontally under this platform. The light source on the first
mirror base 204 under the first document platform 202 radiates
light to the document on this platform. The light reflected by the
document is then reflected by the first mirror on the first mirror
base 204 toward the second mirror base 205.
[0020] Whether the document feeder 201 is used or not, the light
reflected by the document is incident on the CCD 207 via the lens
206 by means of the second and third mirrors on the second mirror
base 205, with the optical path length kept constant.
[0021] The CCD 207 outputs an electric signal based on the quantity
of light reflected by the document. The electric signal is input as
image data into the image former 300.
[0022] The image former 300 includes a processing station 30. The
processing station 30 includes a photosensitive drum 31, a charger
32, an exposure device 33, a developing device 34, a transfer belt
35, a drum cleaner 36, and a fixing device 37.
[0023] The photosensitive drum 31 has a photosensitive layer formed
on its cylindrical surface and rotates clockwise in FIG. 1.
[0024] The charger 32 charges the cylindrical surface of the
photosensitive drum 31 uniformly to a specified electric potential.
The charger 32 may be either a non-contact type charger or a
contact type charger with a roller or a brush.
[0025] The exposure device 33 irradiates the cylindrical surface of
the photosensitive drum 31 with light based on the image data from
the scanner 200. Photoconduction in the photosensitive layer of the
drum 31 forms an electrostatic latent image on the irradiated
surface of the drum 31. The exposure device 33 scans the drum
surface axially of the drum 31 by means of a polygon mirror with a
laser beam modulated with the image data. The exposure device 33
might be replaced by an exposure device having an array of ELs,
LEDs, or other light emitting devices.
[0026] The developing device 34 supplies the cylindrical surface of
the photosensitive drum 31 with toner so as to convert the
electrostatic latent image into a toner image, which is
visible.
[0027] The transfer belt 35 runs in a loop over rollers under the
photosensitive drum 31 and has an electric resistance between about
1.times.10.sup.9 and 1.times.10.sup.13 .OMEGA.cm.
[0028] A transfer roller 35A is supported inside the transfer belt
35 and biased to bring it into compressive contact with the
cylindrical surface of the photosensitive drum 31. The transfer
roller 35A corresponds to the transferrer of the present invention.
A transfer voltage is applied to the transfer roller 35A, so that a
transfer field is formed in a transfer zone 35B on a feed passage
11 under the drum 31.
[0029] The toner image carried by the photosensitive drum 31 is
transferred to a sheet of paper passing through the nip between the
drum and the transfer belt 35.
[0030] A belt cleaner 35C removes the toner, paper dust, and other
dust sticking to the transfer belt 35.
[0031] The drum cleaner 36 removes the toner remaining on the
portion of the drum surface from which the toner image has been
transferred to the sheet passing under the photosensitive drum
31.
[0032] The processing station 30 further includes a thermister 39,
which corresponds to the temperature sensor of the present
invention, for sensing the temperature in the apparatus 100. The
thermister 39 is positioned downstream from the fixing device 37 in
the air flow created by a fan 40 in the apparatus 100. The
thermister 39 can sense the temperature in the apparatus 100 which
is raised by the heat radiated from the fixing device 37.
[0033] The fixing device 37 includes a heating roller 37A and a
press roller 37B. The heating roller 37A is fitted with a heater
lamp in it for heating it to the temperature at which the toner on
a sheet of paper passing through the nip between the rollers 37A
and 37B can melt. The press roller 37B is biased into compressive
contact with the heating roller 37A so as to press the sheet
passing through the roller nip. As a result, the toner image
transferred to the sheet is fixed on it.
[0034] The paper feeder 400 includes feed cassettes 401-404 and a
manual feed tray 405. Each of the feed cassettes 401-404 holds
sheets of paper (record media) of a size. The feed tray 405
supports a sheet of paper of a size or quality for less frequent
use.
[0035] The paper feeder 400 feeds sheets of paper one after one
from one of the feed cassettes 401-404 or the manual feed tray 405.
A sheet fed from the feeder 400 is then fed to the processing
station 30 through the feed passage 11.
[0036] With reference to FIG. 2, the feed cassette 403 which is the
feeding device of the present invention includes a main body 1, a
support plate 2, a pivot plate 3, a rear end guide 4, a pair of
front end guides 5, a pair of side edge guides 6, and a press plate
7.
[0037] The cassette body 1 is a hollow rectangular parallelepiped
open at its top and holds a pile of sheets of paper in it. The
support plate 2, pivot plate 3, end guides 4 and 5, edge guides 6,
and press plate 7 are positioned in the cassette body 1.
[0038] A feed mechanism 410 feeds the sheets in the cassette body 1
one after one in downward order in a feed direction X. The feed
mechanism 410 includes a pickup roller 411, a feed roller 412, a
parting plate 413, and a belt 414. The feed roller 412 rotates
counterclockwise in FIG. 2 and drives the belt 414, which rotates
the pickup roller 411 in the same direction.
[0039] The feed mechanism 410 feeds the sheets, with the pickup
roller 411 shifted downward around the feed roller 412 so that the
cylindrical surface of the pickup roller 411 is in contact with a
specified region of the upper side of the top sheet in the cassette
body 1. The pickup roller 411 rotates with its cylindrical surface
in contact with the top sheet, exerting feed force on the sheet so
as to feed the sheet in the feed direction X to the nip between the
feed roller 412 and parting plate 413.
[0040] If the pickup roller 411 feeds two or more sheets at a time,
only the top sheet passes through the nip between the feed roller
412 and parting plate 413, while the other sheet or sheets are
stopped by the friction between it or them and the plate 413.
[0041] The support plate 2 is shorter in the feed direction X than
the minimum size of the sheets which can be held in the cassette
body 1. The support plate 2 is supported pivotably at its rear end
2A on the bottom of the cassette body 1. Sheets of paper are held
in the cassette body 1, with the bottom sheet partially lying on
the support plate 2.
[0042] The pivot plate 3 is positioned under the support plate 2
and supported pivotably at its front end 3A on the bottom of the
cassette body 1. The torque from a motor (not shown) biases the
pivot plate 3 in a direction C around the front end 3A of this
plate, so that the rear end of the pivot plate 3 shifts the support
plate 2 in the opposite direction D around the rear end 2A of this
plate. A spring could be used in place of the motor.
[0043] The rear end guide 4 can reciprocate in the feed direction X
and the opposite direction on the bottom of the cassette body 1 and
keeps in contact with the rear ends of the sheets in the body so as
to regulate the positions of the sheets.
[0044] The front end guides 5 can move vertically in the cassette
body 1. The heads of the front guides 5 keep in contact with the
upper sides of the front corners of the top sheet in the cassette
body 1. The front end guides 5 separate the top sheet from the
other sheets in the cassette body 1.
[0045] The side edge guides 6 can reciprocate in cross directions Y
(FIG. 3), which are perpendicular to the feed direction X, on the
bottom of the cassette body 1 and keep in contact with the side
edges of the sheets in the body so as to regulate the positions of
the sheets.
[0046] The rear end guide 4 and side edge guides 6 can be shifted
on the bottom of the cassette body 1 according to the size of the
sheets in the body.
[0047] With reference to FIG. 3, the press plate 7 is substantially
rectangular and flat. The press plate 7 is not smaller in the
directions X and Y than the maximum size of the sheets which can be
held in the cassette body 1. The press plate 7 is not larger in
these directions than the inner size of the cassette body 1. The
press plate 7 has a first opening 7B, a support opening 7C, a pair
of second openings 7D, and a pair of third openings 7E.
[0048] The first opening 7B is formed over the specified region of
the upper side of the top sheet in the cassette body 1. When the
pickup roller 411 shifts downward around the feed roller 412, the
pickup roller 411 passes through the first opening 7B, so that the
cylindrical surface of this roller comes into contact with this
region of the top sheet. With the roller surface in contact with
the top sheet, the rotation of the pickup roller 411 exerts feed
force on the sheet.
[0049] The rear end guide 4 passes vertically through the support
opening 7C, which restricts the forward and backward movements of
the press plate 7 while this plate is moving vertically in the
cassette body 1. The top of the rear end guide 4 is exposed, so
that this guide is easy to pull out through the support opening 7C.
Accordingly, the press plate 7 can be removed upward from the rear
end guide 4. The rear end guide 4 functions as the support of the
present invention.
[0050] Alternatively, the cassette body 1 might be fitted with a
support on one side of it, with which part of the press plate 7
would engage vertically movably. In this case, the rear end guide 4
would not function as the support.
[0051] Each of the front end guides 5 can move vertically through
one of the second openings 7D. Each of the side edge guides 6
passes vertically through one of the third openings 7E.
[0052] With the press plate 7 removed from the cassette body 1,
sheets of paper are put into the body. Subsequently, the press
plate 7 is placed on the top sheet in the cassette body 1, with the
support opening 7C engaging with the rear end guide 4. This enables
the press plate 7 to move vertically. Without external force
exerted on the press plate 7, the weight of this plate makes it
rest on the top sheet.
[0053] The press plate 7 covers the top sheet in the cassette body
1 except where the sheet is exposed through the openings 7B-7E. As
a result, the substantially whole area of the top sheet is not
exposed to the atmosphere. This keeps the top sheet from getting so
moist in a humid atmosphere that the pickup roller 411 might slip
on the sheet and misfeed it.
[0054] As the number of sheets in the cassette body 1 decreases,
the support plate 2 shifts in the direction D (FIG. 2), so that
front portions of the sheets tilt in this direction. If the press
plate 7 kept flat, it could not keep in close contact with the
upper side of the top sheet in the cassette body 1.
[0055] The press plate 7 includes a flexing portion 7A extending
across it in the cross directions Y. The flexing portion 7A divides
the press plate 7 into a front part and a rear part, the angle
between which can vary. Even when the inclination of front portions
of the sheets in the cassette body 1 varies, as shown in FIGS. 4A
and 4B, the press plate 7 keeps in close contact with a wide area
of the top sheet in the body.
[0056] The flexing portion 7A may be made of a flexible material of
a specified length in the direction X. An elastic member may be
stuck to the under side of the press plate 7 so that this plate can
more reliably cover the top sheet in the cassette body 1.
[0057] The press plate 7 may be made of a transparent material.
This makes it possible to observe the type and states of the sheets
in the cassette body 1 visually without removing the press plate
7.
[0058] FIG. 5 shows the press plate 71 of a feed cassette according
to another embodiment of the present invention. The press plate 71
has a front cutout 71B and a pair of side cutouts 71E, which
correspond to the first opening 7B and third openings 7E
respectively of the press plate 7.
[0059] The two embodiments have been described with an image
forming apparatus exemplifying a paper processing apparatus.
However, the present invention can be applied likewise to other
paper processing apparatus than image forming apparatus which holds
a pile of sheets of paper.
[0060] The present invention being thus described, it will be
obvious that the invention may be varied in many ways. Such
variations are not to be regarded as a departure from the spirit
and scope of the invention, and all such modifications as would be
obvious to one skilled in the art are intended to be included
within the scope of the following claims.
* * * * *