U.S. patent application number 12/585181 was filed with the patent office on 2010-03-11 for paper feeder and image forming device.
This patent application is currently assigned to RICOH COMPANY, LTD.. Invention is credited to Hiroshi Fujiwara, Haruyuki Honda, Toshikane Nishii, Mizuna Tanaka.
Application Number | 20100059930 12/585181 |
Document ID | / |
Family ID | 41798535 |
Filed Date | 2010-03-11 |
United States Patent
Application |
20100059930 |
Kind Code |
A1 |
Tanaka; Mizuna ; et
al. |
March 11, 2010 |
Paper feeder and image forming device
Abstract
A paper feeder includes a sheet container including a platen
member on which sheet-like recording media is placed, the platen
member having one end portion on an upstream side of a paper feed
direction rotatably supported to a spindle, such that the other end
portion on a downstream side of the paper feed direction is lifted,
and a paper feed member which draws and feeds the sheet-like
recording media, and the sheet container includes a stepped portion
which presses down the downstream side of the paper feed direction
of the platen member when inserting the sheet container in the
direction opposite to the paper feed direction, and a sliding
portion which maintains the pressing down.
Inventors: |
Tanaka; Mizuna; (Osaka,
JP) ; Honda; Haruyuki; (Osaka, JP) ; Fujiwara;
Hiroshi; (Osaka, JP) ; Nishii; Toshikane;
(Osaka, JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 8910
RESTON
VA
20195
US
|
Assignee: |
RICOH COMPANY, LTD.
|
Family ID: |
41798535 |
Appl. No.: |
12/585181 |
Filed: |
September 8, 2009 |
Current U.S.
Class: |
271/162 |
Current CPC
Class: |
B65H 1/266 20130101;
B65H 1/12 20130101; B65H 2403/513 20130101; B65H 2405/1117
20130101; B65H 2801/06 20130101 |
Class at
Publication: |
271/162 |
International
Class: |
B65H 1/04 20060101
B65H001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2008 |
JP |
2008-229894 |
Claims
1. A paper feeder, comprising: a sheet container including a platen
member on which sheet-like recording media is placed, the platen
member having one end portion on an upstream side of a paper feed
direction rotatably supported to a spindle, such that the other end
portion on a downstream side of the paper feed direction is lifted;
and a paper feed member which draws and feeds the sheet-like
recording media, the sheet container including a stepped portion
which presses down the downstream side of the paper feed direction
of the platen member when inserting the sheet container in the
direction opposite to the paper feed direction, and a sliding
portion which maintains the pressing down.
2. The paper feeder according to claim 1, wherein the stepped
portion and the sliding portion are pressed to a locking member by
a biasing member which elastically supports the platen member.
3. The paper feeder according to claim 1, wherein the stepped
portion and the sliding portion are integrally provided in the
platen member.
4. The paper feeder according to claim 2, wherein the stepped
portion and the sliding portion are integrally provided in the
platen member.
5. The paper feeder according to claim 1, wherein the stepped
portion is provided above a straight line connecting the spindle of
the platen member and a leading end of the platen member.
6. The paper feeder according to claim 1, wherein a relationship of
Ls/L>f/F is satisfied where a biasing force of the platen member
to the paper feed member is F, a sliding load in the platen member
and the sliding portion is f, a distance from the spindle of the
platen member to a biasing position is Ls, and a distance from the
spindle to the stepped portion is L.
7. The paper feeder according to claim 1, wherein the sheet
container includes a control member which controls a top sheet of
the sheet-like recording media, and a relationship of Lt/L>Y/y
is satisfied where a height from a surface from which the
sheet-like recording media is fed in the platen member to the
control member is Y, a height of the stepped portion y, a distance
from the spindle of the platen member to a leading end position of
the platen member is Lt, and a distance from the spindle to the
stepped portion is L.
8. The paper feeder according to claim 1, wherein the stepped
portion is formed in a circular shape and the circular stepped
portion is concentric with the spindle of the platen member.
9. An image forming device comprising the paper feeder set forth in
claim 1.
Description
PRIORITY CLAIM
[0001] The present application is based on and claims priority from
Japanese Patent Application No. 2008-229894, filed on Sep. 8, 2008,
the disclosure of which is hereby incorporated by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a paper feeder which draws
a sheet-like recording medium such as paper from a paper feed tray,
and feeds the sheet-like recording medium, and to an image forming
device such as a copier, a printer, a facsimile each having the
paper feeder, or a device having two of these functions.
[0004] 2. Description of the Related Art
[0005] A conventional paper feeder including a unit which contains
a stack of sheet-like recording media such as paper (hereinafter,
recording paper) has a rotatable platen which biases the recording
paper stack by means of a pressing unit such as a spring such that
the top sheet of the recording paper stack has contact with a paper
feed roller. In such a paper feeder, the top sheet of recording
paper stack is fed by the paper feed roller, and the recording
paper stack is separated sheet by sheet by a separator such as a
friction pad.
[0006] FIG. 3 is a structural view of a conventional paper feeder,
which illustrates a relationship between a feed part of recording
paper P and a separator. Referring to FIG. 3, a paper feed roller
48 is disposed in the paper feeder on the downstream side of the
paper feed direction of a paper feed tray, and a friction pad 49
which separates the recording paper P is disposed in the paper feed
tray on the downstream side of the paper feed direction. The
friction pad 49 is made of a material which generates dynamic
friction resistance larger than that between recording paper, and
generates predefined dynamic friction resistance by predetermined
pressure applied from a spring 52 via a retaining member 51. When
two sheets of the recording paper P are fed on top of one another,
the sheet which has contact with the paper feed roller 48 is
separated from the sheet which has contact with the friction pad 49
because the dynamic friction between the recording paper is smaller
than the dynamic friction between the recording paper P and the
friction pad 49.
[0007] The paper feed tray provided with the friction pad 49, the
retaining member 51 and the spring 52 includes a platen 53 having a
top face to which the recording paper P is placed. The end portion
of the platen 53 on the paper feed roller 48 side is elastically
biased upward by the spring 52, and is always biased in the
direction of the paper feed roller 48 regardless of the carrying
capacity of the recording paper.
[0008] If a paper feed operation is performed without placing the
recording paper stack in an appropriate position, i.e., a large
number of sheets exceed the friction pad 49 by inertia force or the
like in the operation of the paper feed tray, the sheets are not
separated. For this reason, the sheets are fed on top of one
another. If the paper feed operation is performed without placing
the recording paper stack in an appropriate position, i.e., more
than the expected amount of recording sheets are disposed between
the paper feed face and the paper feed roller, the paper feed
roller becomes overloaded, resulting in the inability to rotate,
which stops the feeding. Moreover, due to such an overload, the
recording paper becomes damaged, and the paper feeder becomes
overloaded, thereby causing problems relating to paper insertion
and drawing operations of the paper feed tray.
[0009] In order to place the recording paper stack in an
appropriate position, a paper feeder including mechanism capable of
locking a platen in a lower position and releasing the lock when
the paper feed tray is housed in the paper feeder is provided. When
a user places the recording paper, the user locks the platen in
this paper feeder.
[0010] FIG. 4 is a view illustrating the end portion of the platen
on the paper feed roller side when the platen is locked in a lower
position. In addition, reference number 41 denotes a paper feed
tray. In this case, a user pushes down the platen 53 when placing
the recording paper P, so as to lock the platen 53 in a defined
position. Then, the user houses the paper feed tray 41 in the paper
feeder, so that the paper feed operation is started while
maintaining the recording paper in an appropriate position.
[0011] However, the paper feed tray may be inserted in the paper
feeder without locking the platen 53 by an operation error of a
user. FIG. 5 is a view illustrating a condition in which the platen
is not locked in a lower position. Since a member which controls
the recording paper P is not provided in the platen 53 on the
downstream side of the paper feed direction, the recording paper P
is placed in an inappropriate position by inserting and drawing the
paper feed tray 41.
[0012] If the paper feed tray is housed in the paper feeder in this
condition, the recording paper P is placed as illustrated in FIG.
6. FIG. 6 is a view illustrating the platen set in the paper feeder
without being locked in a lower position. As illustrated in FIG. 6,
a large number of sheets enter into a position exceeding the end
portion of the friction pad 49 on the upstream side of the paper
feed direction, so that the sheets are fed on top of one another
upon the start of the paper feed operation. The paper feed roller
48 is thereby overloaded according to the amount of recording paper
P that enters that position, resulting in the inability of the
paper feed operation and damage to the recording paper. If the
paper feed tray is overloaded, the inserting and drawing operation
of the tray may not be able to be performed. Accordingly, the above
problems depend on a user's operation as to whether performing the
locking operation of the platen or not. A method of placing
recording paper stack in an appropriate position by lowering a
platen in response to the housing operation of a paper feed tray in
the paper feeder is proposed. With this method, however, depending
on the housing operation of the paper feed tray, inertia force
relative to the recording paper is generated, so that the recording
paper stack may not be placed in an appropriate position.
[0013] JP H05-97255A describes that a position of an end face is
changed according to a position of recording paper when the
recording paper is placed in an inappropriate position in a paper
feed cassette, so as to prevent the recording paper from being
damaged when the recording paper is placed in an inappropriate
position. Moreover, JP2003-246480A describes that a control member
which projects downwardly is provided in a part of an image forming
device, so as to prevent a feeding error of a sheet by the running
of the leading end of the sheet over a separation inclination face,
which shifts the sheet in an inappropriate position.
[0014] The techniques described above are aimed to prevent sheets
from being fed on top of one another. Such feeding, however, can
not be completely prevented by the above techniques.
SUMMARY OF THE INVENTION
[0015] It is, therefore, an object of the present invention to
provide a paper feeder which prevents a paper feeding error and an
operation error by guiding recording paper to an appropriate
position.
[0016] A first aspect of the present invention relates to a paper
feeder, comprising: a sheet container including a platen member on
which sheet-like recording media is placed, the platen member
having one end portion on an upstream side of a paper feed
direction rotatably supported by a spindle, such that the other end
portion on a downstream side of the paper feed direction is lifted;
and a paper feed member which draws and feeds the sheet-like
recording media, the sheet container including a stepped portion
which presses down the downstream side of the paper feed direction
of the platen member when inserting the sheet container in the
direction opposite to the paper feed direction, and a sliding
portion which maintains the pressing down.
[0017] Preferably, the stepped portion and the sliding portion are
pressed to a locking member by a biasing member which elastically
supports the platen member.
[0018] Preferably, the stepped portion and the sliding portion are
integrally provided in the platen member.
[0019] Preferably, the stepped portion is provided above a straight
line connecting the spindle of the platen member and a leading end
of the platen member.
[0020] Preferably, a relationship of Ls/L>f/F is satisfied where
a biasing force of the platen member to the paper feed member is F,
a sliding load in the platen member and the sliding portion is f, a
distance from the spindle of the platen member to a biasing
position is Ls, and a distance from the spindle to the stepped
portion is L.
[0021] Preferably, the sheet container includes a control member
which controls a top sheet of the sheet-like recording media, and a
relationship of Lt/L>Y/y is satisfied where a height from a
surface from which the sheet-like recording media is fed in the
platen member to the control member is Y, a height of the stepped
portion y, a distance from the spindle of the platen member to a
leading end position of the platen member is Lt, and a distance
from the spindle to the stepped portion is L.
[0022] Preferably, the stepped portion is formed in a circular
shape and the circular stepped portion is concentric with the
spindle of the platen member.
[0023] A second aspect of the present invention relates to an image
forming device including the above paper feeder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings are included to provide further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate an
embodiment of the invention and, together with the specification,
serve to explain the principle of the invention.
[0025] FIG. 1 is a view illustrating a schematic structure of an
image forming device according to one embodiment of the present
invention.
[0026] FIG. 2 is a view illustrating a structure of a paper feed
tray in a paper feeder and a part of the image forming device near
the paper feed tray.
[0027] FIG. 3 is a view illustrating a structure of a conventional
paper feeder.
[0028] FIG. 4 is a view illustrating an end portion of a
conventional platen on a paper feed roller side when the platen is
locked in a lower position.
[0029] FIG. 5 is a view illustrating a conventional platen when the
platen is not locked.
[0030] FIG. 6 is a view when the conventional platen is set in a
main body of an image forming device without being locked in a
lower position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] Hereinafter, an embodiment of the present invention will be
described with reference to the accompanying drawings.
[0032] Referring to FIG. 1 illustrating a schematic structure of an
image forming device according to one embodiment of the present
invention, the image forming device is a tandem color image forming
device of an indirect transfer system as a printer in which four
color image forming units, cyan (C), magenta (M), yellow (Y) and
black (K), each having one development station on an outer
circumferential surface of an image carrier are arranged. In FIG.
1, the development station and the image carrier unit are mounted
on the main body of the image forming device.
[0033] In FIG. 1, the color image forming device includes an
optical writing station 2, an image forming station 3, a paper feed
station 4, a fusing station 5, a paper discharging station 6, and a
transport station 7.
[0034] The details of the optical writing station 2 are not
illustrated in the figure. In the optical writing station 2, an LD
unit as a light source emits laser light of respective colors, the
respective emitted laser light is irradiated on photoreceptor drums
31C, 31M, 31Y, 31K, which are image carriers of the image forming
units 30C, 30M, 30Y, 30K of the image forming station 3, via a
polygon mirror and a plurality of reflection mirrors, so as to
perform laser writing. The laser writing is conducted by
irradiating laser light modulated by modulation signals obtained
according to writing data, so that latent images are formed on the
surfaces of the photoreceptor drums 31C, 31M, 31Y, 31K,
respectively.
[0035] The image forming station 3 is disposed in the central
portion of the main body of the image forming device 1, and
includes the image forming units of respective colors 30C, 30M,
30Y, 30K, an intermediate transfer belt 38 as an image carrier, and
a secondary transfer roller 39. The image forming units 30C, 30M,
30Y, 30K include the photoreceptor drums 31C, 31M, 31Y, 31K,
respectively. Electrophotography forming elements are disposed
along the outer circumference of each photoreceptor drum 31C, 31M,
31Y, 31K. In this embodiment, since the same structure is applied
for each color, a reference sign for black (K) is only applied, and
reference signs for other colors (C, M, Y) will be omitted. The
image forming units each having the same structure are arranged in
series along the moving direction of the intermediate transfer belt
38. Moreover, when generally describing each element, the reference
signs indicating colors C, M, Y, K will be omitted.
[0036] The photoreceptor drum 31K includes, as the image formation
elements, in the outer circumference thereof in the clockwise
direction a charging roller 32K which charges the surface of the
photoreceptor drum 31K, a development units 33K which houses
developer including toner and develops a latent image on the
photoreceptor drum 31K as a toner image, a primary transfer roller
34K which transfers the toner image on the photoreceptor drum 31K
onto the intermediate transfer belt 38, a cleaning unit 35K having
a cleaning blade which scrapes residual toner after the primary
transfer, and an electricity removal unit (not shown) which removes
electric charge remaining on the photoreceptor drum 31K after the
primary transfer. The laser light 21K performs optical writing from
an exposure unit 36K placed between the charging roller 32K and the
development unit 33K. The image forming units 30C, 30M, 30Y, 30K
are arranged in order along the movement direction (arrow A
direction) of the intermediate transfer belt 38. The primary
transfer roller 34K is disposed in a position which faces the
photoreceptor drum 31K while sandwiching the intermediate transfer
belt 38 therebetween. Reference number 37 is a collection unit
which collects waste toner.
[0037] The secondary transfer roller 39 is provided on the upstream
side of the paper feed direction of the intermediate transfer belt
38 of the image forming unit 30C while sandwiching a recording
paper transport path 42 from the paper feed station 4 therebetween.
The secondary transfer roller 39 transfers the toner image on the
intermediate transfer belt 38 onto recording paper P (sheet-like
recording media). In addition, the residual toner after the
transfer of the secondary transfer roller 39 is cleaned by an
intermediate transfer belt cleaning unit 38a provided on the
upstream side of the image forming unit 30C which is the downstream
side of the paper feed direction of the intermediate transfer belt
38 of the secondary transfer roller 39, and is sent to the image
forming unit on the downstream side.
[0038] Negative bias voltage in which alternate current and direct
current from a not shown bias power source are superimposed is
applied to a core of the development roller 33a (33aK in FIG. 1) of
each development unit 33. Direct negative voltage is applied to
each charging roller 32 from another bias power source.
[0039] The cleaning blade of the cleaning unit 35 cleans toner
remaining on the outer circumferential surface of the photoreceptor
drum 31. The charging roller 32 uniformly charges the outer
circumferential surface of the cleaned photoreceptor drum 31 to a
high potential, so that the charged charging roller 32 is
initialized. Then, the laser beam 21 is irradiated on the
photoreceptor drum 31 of the image forming unit 30 of each color,
and the outer circumferential surface of the photoreceptor drum 31
of each color, which is uniformly charged to high potential is
selectively exposed by laser light modulated according to the image
data. By this exposure, an electrostatic latent image having a low
potential part in which the electric potential is attenuated by the
exposure and a high potential part by the initialization is formed.
The development unit 33 transfers the toner to the low potential
part (or high potential part) of the electrostatic latent image so
as to form (develop) the toner image. The photoreceptor drum 31
transfers the toner image to the intermediate transfer belt 38
while rotating and carrying the toner image.
[0040] The operation of image forming units 30K, 30Y, 30M, 30C is
timely performed such that the four-color (CMYK) toner images
formed on the outer circumferential surfaces of the photoreceptor
drums 31K, 31Y, 31M, 31C, respectively, are timely transferred onto
the same position of the intermediate transfer belt 38 to be
overlapped, and a full color toner image is thereby formed.
[0041] The full color toner image on the intermediate transfer belt
38 is transferred onto the recording paper P transported along the
transport path 42 from the paper feed station 4 by the secondary
transfer roller 39, is fused by heat and pressure in the fusing
station 5, and then is discharged onto the discharging tray 6b by
the discharging roller 6a of the paper discharging station 6. Here,
in a paper feed tray 41 (sheet container) of the paper feed station
4, which houses a recording paper stack, the recording paper P is
separated sheet by sheet by a paper feed roller 48 (paper feed
member) and a friction pad 49, the separated sheet is transported
to the resist roller 46, and the leading end of the separated sheet
of the recording paper P has contact with a nip of the resist
roller 46 such that the leading end is aligned. The resist roller
46 temporarily stops the transport of the recoding paper P, and
timely starts rotating such that the toner image of the
intermediate transfer belt 38 and the leading end of the recording
paper P are located in a predetermined position.
[0042] When forming an image on both faces of the recording paper
P, an image is transferred onto the first face of the recording
paper P by the secondary transfer roller 39. Then, the rotation
direction of the paper discharging roller 6a is reversed when the
back end of the recording paper P fused by the fusing station 5 is
passed a switching point 71, and the leading end and the back end
of the recording paper P are switched, and then the recording paper
is transported to the transport path 72. The recording paper P is
again transported to the resist roller 46 via a re-feeding path 74,
and is sent to the secondary transfer roller 39 side by the resist
roller 46 at the toner image's timing, which is formed on the
intermediate transfer belt 38. Then, the toner image is transferred
onto the second face of the recording paper P. The recording paper
P having an image on the second face is fused by the fusing station
5, and discharged onto the discharging tray 6b from the paper
discharging roller 6a. In addition, a filler 73 which detects paper
is provided near the upstream side of the paper feed direction of
the switching point 71. In addition, reference number 44 is a
filler which detects the passage of the paper supplied from the
paper feed tray 41 or the paper fed via the re-feeding path 74.
[0043] The paper feed station 4 includes the paper feed tray 41
which houses unused recording paper P. This paper feed tray 41 is
disposed to be drawable in the right direction in FIG. 1 together
with the friction pad 49 and the installation position of the
re-feeding path 74 while leaving the paper feed roller 48, a sensor
45 which detects recording paper, and the like in the main body of
the image forming device.
[0044] FIG. 2 is a view illustrating the structure of the paper
feed tray in the paper feeder and the structure of a part of the
image forming device near the paper feed tray. The paper feed tray
41 includes inside thereof a platen 53 (platen member). The platen
53 includes on both side portions thereof side walls 61 which
extend in the paper feed direction. Since a spindle 62 (rotation
axis) having both ends attached to the main body of the paper
feeder penetrates the end portions of the side walls 61 on the
upstream side of the paper feed direction, the platen 53 is
rotatable about the spindle 62. A spring (biasing member) 54 is
disposed in the back face of the platen 53 on the downstream side
of the paper feed direction. The platen 53 is elastically biased
upward by the spring 54, and is supported such that the end portion
has elastic contact with the paper feed roller 48.
[0045] The side wall 61 of the platen 53 extends near the end
portion of the platen 53 on the downstream side of the paper feed
direction. The upper end portion of the side wall 61 includes a
sliding face (sliding portion) 63 which substantially extends in
the horizontal direction and has contact with a lower face of a rib
(locking member) 64 provided in the main body of the image forming
device. Since the sliding face 63 is formed in the upper end
portion of the side wall 61, the sliding face 63 and the platen 53
move together. The height of the sliding face 63 is set such that
the sliding face does not have contact with the rib 64 when the
platen 53 is locked in a lower position as illustrated in FIG. 4.
The sliding face 63 includes a circular stepped portion 63a which
has contact with the rib 64 provided in the main body of the image
forming device when the platen 53 is inserted into the main body of
the image forming device without being locked in a lower position.
The height of the sliding face 63 is also set such that the platen
53 is pushed down to the locking position by the rib 64 after
passing through the stepped portion 63a when the platen 53 is set
in the main body of the image forming device without being locked.
In addition, reference number 65 is a control member which controls
the top of the recording paper P stack, and is provided in the side
wall of the paper feed tray 41.
[0046] The stepped portion 63a is provided above the straight line
connecting the spindle 62 and the leading end of the platen 53.
Accordingly, inertia force is applied to the recording paper P and
sliding load of the recording paper P and the control member 65 is
reduced by performing an operation lowering the platen 53; thus,
the moving amount of the recording paper P by the inertial force
can be improved. More particularly, if the paper feed tray 41 is
inserted into the main body of the image forming device without
locking the platen 53, the stepped portion 63a hits the rib 64, and
then if the paper feed tray 41 is further pushed to the main body
of the image forming device, the stepped portion 63a is guided by
the rib 64, and the platen 53 is lowered. Therefore, the recording
paper P can be placed in an appropriate position by the inertial
force of the recording paper P in the inserting direction of the
paper feed tray 41 when the stepped portion 63a hits the rib 64,
and the upward inertial force of the recording paper P when the
platen 53 is lowered. In addition, even if the paper feed tray 41
is inserted into the main body of the image forming device without
locking the platen 53, the load by the contact and sliding between
the recording paper P and the control member 65 can be reduced
because the platen 53 is lowered. Since the stepped portion 63a has
a circular form and is concentric with the spindle 62 which is the
rotation axis of the platen 53, the reaction force in the stepped
portion 63a can be constantly maintained regardless of an angle of
the platen 53.
[0047] If a relationship of Ls/L>f/F is satisfied where biasing
force of the platen 53 to the paper feed roller 48 is F, sliding
load in the paper feed tray 41 and a sliding portion of the main
body of the device is f, a distance from the spindle 62 of the
platen 53 to a biased position is Ls, and a distance from the
spindle 62 to the stepped portion 63a is L, the reaction force in
the stepped portion which is necessary for moving the recording
paper P to a regular position can be obtained while using the
biasing force of the platen 53.
[0048] Since the paper feed tray 41 includes the control member 65
which controls the top of the recording paper P stack, if a
relationship of Lt/L>Y/y is satisfied where a height from a
surface from which the recording paper in the paper feed tray 41 is
fed to the control member 65 is Y, a height of the stepped portion
63a is y, a distance from the spindle 62 to the position of the
leading end of the platen 53 is Lt, and a distance from the spindle
62 to the stepped portion 63a is L, the recording paper P can be
positioned in a regular position by lowering the top face of the
recording paper P stack when inserting the paper feed tray 41 into
the main body of the image forming device than the paper feed
face.
[0049] As described above, when inserting the paper feed tray into
the main body of the image forming device, the platen 53 slides
with the rib 64 provided in the main body of the image forming
device. The stepped portion 63a is provided on the sliding face 63
of the platen 53. When inserting the paper feed tray 41 into the
main body of the image forming device with the platen 53 being
locked in a lower position, the sliding portion 63 and the stepped
portion 63a do not have contact with the rib 64; however, the
stepped portion 63a has contact with the rib 64 when inserting the
paper feed tray 41 into the main body of the image forming device
without locking the platen 53 in a lower position, so that reaction
force is generated in the platen 53. By this reaction force,
inertial force is applied to the recording paper P, so that the
recording paper P moves in the inserting direction of the paper
feed tray 41 (position which controls the back end of the recording
paper P. For this reason, the recording paper P can be moved to an
appropriate position even when inserting the paper feed tray 41
without locking the platen 53; thus, the problems can be prevented.
If the stepped portion 63a has contact with the rib 64, the platen
53 rotates in the direction lowering the platen 53, so that the
sliding load of the control member 65 on the upper end of a sheet
and the recording paper is reduced, and loss to the inertial force
can be controlled. Therefore, the moving amount of the recording
paper can be sufficiently ensured.
[0050] According to the embodiment of the present invention, when
inserting the paper feed tray (sheet container) into the main body
of the image forming device, the operational ability when inserting
is increased, so that the inertial force is generated in the
sheet-like recording paper which is not placed in an appropriate
position. Therefore, the recording paper can be guided to an
appropriate position, and the feeding error and operation error can
be thereby prevented.
[0051] Although the embodiments of the present invention have been
described above, the present invention is not limited thereto. It
should be appreciated that variations may be made in the
embodiments described by persons skilled in the art without
departing from the scope of the present invention.
* * * * *