U.S. patent application number 11/346175 was filed with the patent office on 2006-08-10 for sheet conveyance apparatus and image reading apparatus.
This patent application is currently assigned to CANON DENSHI KABUSHI KAISHA. Invention is credited to Takashi Machida.
Application Number | 20060175748 11/346175 |
Document ID | / |
Family ID | 36779151 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060175748 |
Kind Code |
A1 |
Machida; Takashi |
August 10, 2006 |
Sheet conveyance apparatus and image reading apparatus
Abstract
A sheet conveyance apparatus includes a conveyance roller which
conveys a sheet and an elastic guide member one end of which is
fixed and supported, the other end of which faces the conveyance
roller as a free end, and which can be elastically transformed. The
conveyed sheet is sandwiched between the conveyance roller and the
elastic guide member, and the elastic guide member is elastically
transformed to bring the sheet into press contact with the
conveyance roller.
Inventors: |
Machida; Takashi;
(Niiza-Shi, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON DENSHI KABUSHI KAISHA
CHICHIBU-SHI
JP
|
Family ID: |
36779151 |
Appl. No.: |
11/346175 |
Filed: |
February 3, 2006 |
Current U.S.
Class: |
271/264 ;
271/314 |
Current CPC
Class: |
B65H 2404/6942 20130101;
B65H 2404/61 20130101; B65H 5/06 20130101 |
Class at
Publication: |
271/264 ;
271/314 |
International
Class: |
B65H 5/00 20060101
B65H005/00; B65H 29/20 20060101 B65H029/20 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2005 |
JP |
2005-031440 |
Claims
1. A sheet conveyance apparatus comprising: a conveyance roller
which conveys a sheet; and an elastic guide member one end of which
is fixed and supported, the other end of which faces the conveyance
roller as a free end, and which can be elastically transformed, and
wherein the conveyed sheet is sandwiched between the conveyance
roller and the elastic guide member, and the elastic guide member
is elastically transformed to bring the sheet into press contact
with the conveyance roller.
2. The sheet conveyance apparatus according to claim 1, comprising
a conveyance path through which the sheet conveyed by the
conveyance roller passes, wherein the conveyance path has a curved
portion to have a U shape, and the conveyance roller is arranged
inside the curved portion, and the elastic guide member is arranged
outside the curved portion.
3. The sheet conveyance apparatus according to claim 1, wherein the
conveyance roller has a shaft and a roller main body having an
outer peripheral surface which are in contact with the sheet, the
plurality of elastic guide members are arranged on both the sides
of the roller main body; the elastic guide members are not in
contact with the outer peripheral surface of the roller main body,
and a part of the elastic guide member is located closer to the
shaft than a virtual surface obtained by extending the outer
peripheral surface of the roller main body in an axial direction of
the conveyance roller.
4. The sheet conveyance apparatus according to claim 1, wherein
when one conveyance guide unit is used as a combination of the
conveyance roller and the elastic guide member, the plurality of
conveyance guide units are arranged in a direction crossing the
conveyance direction.
5. The sheet conveyance apparatus comprising: a plurality of
conveyance rollers which convey a sheet and which are arranged
along a conveyance direction of the sheet; an elastic guide member
which is fixed and supported at the central portion and both the
ends of which serve as free ends facing an upstream side conveyance
roller and a downstream side conveyance roller of the plurality of
conveyance rollers, respectively; and the conveyed sheet is
sandwiched between the conveyance roller and the elastic guide
member, and the elastic guide member is elastically transformed to
bring the sheet into press contact with the conveyance roller.
6. The sheet conveyance apparatus according to claim 5, wherein the
plurality of elastic guide members are arranged in an axial
direction of the conveyance roller; and central portions of the
plurality of elastic guide members are coupled to each other and
integrated.
7. An image reading apparatus comprising: a sheet conveyance
apparatus according to claim 1; and an image reading unit which
reads an image from a sheet conveyed by the sheet conveyance
apparatus.
8. A sheet conveyance apparatus comprising: a conveyance roller
which has a shaft and a roller main body having an outer peripheral
surface being in contact with a sheet, and which conveys the sheet;
and a plurality of elastic guide members which are arranged on both
the sides of the roller main body in an axial direction of the
conveyance roller, which extend in a conveyance direction, and
which can be elastically transformed, wherein the conveyed sheet is
sandwiched between the conveyance roller and the plurality of
elastic guide members which are elastically transformed, and
elastic force of the elastic guide member brings the sheet into
press contact with the outer peripheral surface of the roller main
body.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a sheet conveyance
apparatus which coneys a sheet and an image reading apparatus which
conveys an original document serving as a sheet to read image
information recorded on the original document.
[0003] 2. Description of the Related Art
[0004] FIG. 8 is a sectional view schematically showing an example
of a sheet conveyance apparatus which reads image information on an
original document 1 while conveying the original document 1 serving
as a sheet to perform printing or the like in an image forming
apparatus such as a copying machine or a facsimile machine. The
sheet conveyance apparatus is singularly used as an image reading
apparatus or arranged so as to be built in an image forming
apparatus main body.
[0005] The original document 1 is sent out from an original base
plate by a pickup roller 2 and taken into the apparatus by a sheet
feeding roller 3. When the sheet is taken into the apparatus by the
sheet feeding roller 3, in order to prevent a plurality of original
documents 1 from overlapping and being taken at once, namely, in
order to prevent so-called double feeding, the original documents 1
are separately fed one by one by a separating roller 4. The
original document 1 is sandwiched and further conveyed by one pair
of opposing registration rollers 5 facing a conveyance path and
caused to pass through one pair of opposing image sensors 6. Pieces
of image information recorded on both the front and rear sides of
the original document 1 are scanned and read. The read original
document 1 is further conveyed to one pair of opposing registration
rollers 7. Thereafter, in this case, a switching lever 8 can switch
the original document 1 to any one of a conveyance path on which
conveyance is performed by feeding the original document 1 to a
U-shaped path 11 or a conveyance path on which conveyance is
performed by feeding the original document 1 to a straight path
(not shown).
[0006] In the U-shaped path 11, one pair of guide rollers 9a and 9b
are arranged opposite to each other while facing a curved path and
sandwich the original document 1 to guide U-turn conveyance. One
pair of opposing discharge rollers 10a and 10b are arranged on the
downstream-side end of the U-shaped path 11, so that the original
document 1 is discharged onto the upper portion of the apparatus.
When the original document 1 is fed to the straight path by
switching the switching lever 8, the original document 1 directly
goes straight out of the registration rollers 7 and is discharged
out of the apparatus.
[0007] On the other hand, as another example of the sheet
conveyance apparatus, a recording medium conveyance apparatus in
which a plurality of pressure rollers are aligned in a line at
intervals, and one long conveyance roller is arranged in parallel
to each rotating axes of the pressure rollers, so that a sheet
serving as a recording medium is sandwiched between the pressure
rollers and the conveyance roller to convey the sheet is known (see
Japanese Patent Application Laid-open No. 10-181929). In this case,
the pressure rollers arranged in the line are supported by holders,
respectively. The pressure roller is biased to be pressed against
the conveyance roller by a coil spring through the holders. In this
manner, the pressure rollers are brought into press contact with
the conveyance roller to obtain an appropriate surface
compaction.
[0008] In the sheet conveyance apparatus shown in FIG. 8, in order
to correctly guide the original document 1 with the curved portion
of the U-shaped path 11, one pair of opposing guide rollers 9a and
9b and one pair of opposing discharge rollers 10a and 10b are
arranged. For this reason, since the guide roller 9b and the
discharge roller 10b arranged outside the curved portion of the
U-shaped path 11 project outside, a dimension L2 represented by
reference numeral L2 in FIG. 8 increases by the projecting
portions. As a result, the housing of the apparatus main body
increases in size disadvantageously.
[0009] In order to avoid this drawback, as shown in FIGS. 9A to 9C,
the e in size of the apparatus can be suppressed as the roller
diameters of the guide rollers 9 and the discharge rollers 10
decrease. However, when the roller diameters decrease, impact
caused by the original document 1 is large when the original
document 1 is inserted between the rollers. As a result, a paper
jam easily occurs. The paper jam becomes conspicuous as the
thickness of the original document 1 increases. For the above
circumstances, there is a limit to reduce the guide rollers 9 or
the discharge rollers 10 in size. Furthermore, a desired contact
pressure must be always applied between the opposing rollers, and
roller rotational loads increase. Accordingly, the rated powers of
the motors must be disadvantageously matched to the roller
rotational loads.
[0010] On the other hand, the recording medium conveyance apparatus
disclosed in Japanese Patent Application Laid-open No. 10-181929 is
constituted by a very large number of members such as the plurality
of coaxial pressure rollers, the holding holders therefor, the
biasing coil springs, and the opposite conveyance roller cooperated
with the pressure rollers. Therefore, the large number of parts
disadvantageously increase manufacturing cost including parts cost
and assembly cost.
SUMMARY OF THE INVENTION
[0011] Therefore, it is a main object of the present invention to
provide a sheet conveyance apparatus which can suppress the
apparatus from increasing in size and can reduce the number of
parts to make it possible to realize a reduction in cost.
Furthermore, it is another object of the present invention to
provide a sheet conveyance apparatus which can also effectively
prevent paper jam of an original document or the like and which can
contribute to an improvement in processing ability of an image
forming apparatus when the sheet conveyance apparatus is installed
in the image forming apparatus.
[0012] In order to achieve the above object, a typical sheet
conveyance apparatus according to the present invention has the
follows: a conveyance roller which conveys a sheet; and an elastic
guide member one end of which is fixedly supported, the other end
of which faces the conveyance roller as a free end, and which can
be elastically transformed, and wherein the conveyed sheet is
sandwiched between the conveyance roller and the elastic guide
member, and the elastic guide member is elastically transformed to
bring the sheet into press contact with the conveyance roller.
[0013] In a conventional conveyance apparatus, a conveyance roller
which conveys a sheet is provided apparatus is strictly restricted
by a parts storage space, a large space is occupied by the two
rollers. For this reason, in the present invention of the
application, one of two opposing conveyance rollers is caused to
function in place of an elastic guide member. The space occupied by
the elastic guide member becomes smaller than the projection of the
roller main body of the conveyance roller. The sheet is fed between
the elastic guide member and the conveyance roller. The elastic
guide member is elastically transformed by contact force generated
when the sheet is fed to escape to the opposite side together with
the conveyance roller. The elastic guide member having appropriate
elastic reactive force cooperates with the conveyance roller so as
to be in press contact with the sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an original document conveyance apparatus serving
as a first embodiment of a sheet conveyance apparatus according to
the present invention.
[0015] FIG. 2 is a perspective view showing a conveyance guide unit
according to the embodiment.
[0016] FIG. 3A is a pattern diagram showing a mode obtained a sheet
is fed into the conveyance guide unit.
[0017] FIG. 3B is a pattern diagram showing a mode obtained when
the sheet is being fed into the conveyance guide unit.
[0018] FIG. 4 is a perspective view showing a second
embodiment.
[0019] FIG. 5 is a diagram showing an original document conveyance
apparatus according to a third embodiment.
[0020] FIG. 6 is a perspective view showing a conveyance guide unit
according to the third embodiment.
[0021] FIG. 7 is a perspective view showing a conveyance guide unit
according to a fourth embodiment.
[0022] FIG. 8 is a diagram showing a conventional original document
conveyance apparatus.
[0023] FIG. 9A is diagram for explaining a problem of the
conventional original document conveyance apparatus.
[0024] FIG. 9B is diagram for explaining a problem of the
conventional original document conveyance apparatus.
[0025] FIG. 9C is diagram for explaining a problem of the
conventional original document conveyance apparatus.
DESCRIPTION OF THE EMBODIMENTS
[0026] An original document conveyance apparatus serving as an
embodiment of a sheet conveyance apparatus according to the present
invention and an embodiment of an image forming apparatus including
the original document conveyance apparatus will be described below
in detail with reference to the drawings. The same reference
numerals as in the sheet conveyance apparatus shown in FIG. 8
denote the same parts and the same members in the embodiments, and
new reference numerals are add to main members as shown in the
drawings subsequent to FIG. 1 to make major points of the
embodiments more clear.
Sheet Conveyance Apparatus--First Embodiment
[0027] As shown in FIG. 1, in the original document conveyance
apparatus according to the embodiment, an original document (sheet)
1 sent out from an original base plate by a pickup roller 2 is
taken into the apparatus by a sheet feeding roller 3. At this time,
in order to prevent a plurality of original documents 1 from
overlapping and being picked up at once, namely, in order to
prevent so-called double feeding, the original documents 1 are
separated and detached from each other one by one by a separating
roller 4. The original document 1 is sandwiched and conveyed by one
pair of opposing registration rollers 5. Furthermore, pieces of
image information recorded on both the front and rear sides of the
original document 1 are scanned and read by one pair of opposing
image sensors 6. The read original document 1 from which the pieces
of image information are read is further conveyed to one pair of
opposing registration rollers 7. Thereafter, the original document
1 can be switched by a switching lever 8 to any one of a conveyance
path on which conveyance is performed by feeding the original
document 1 to a U-shaped path 11 or a conveyance path on which
conveyance is performed by feeding the original document 1 to a
straight path (not shown). On the U-shaped path 11, a conveyance
guide unit according to the embodiment is arranged so as to
sandwich the curved portion of the U-shaped path 11 to guide
conveyance travel of the original document 1. The original document
1 sent out from the conveyance guide unit is discharged onto the
upper portion of the apparatus by discharge rollers 10. When the
original document 1 is fed to the straight path by switching the
switching lever 8, the original document 1 directly goes straight
out of the registration rollers 7 and is discharged out of the
apparatus.
[0028] In the conveyance guide unit, like a conventional conveyance
roller, one conveyance roller 9 is arranged inside of a curved
portion to face a curved portion formed such that a conveyance path
is U-shaped, and an elastic guide member 20 molded in the form of a
band by an elastic material such as a metal, a resin or the like is
arranged outside the curved portion to face the conveyance roller
9. The conveyance roller 9 is constituted by a roller main body 9d
having an outer peripheral surface being in contact with the
original document and a roller rotating shaft 9c. As is apparent
from FIG. 2, the conveyance roller 9 is arranged such that the
roller rotating shaft 9c orthogonally crosses a sheet conveyance
direction (arrow A). Two elastic guide members 20 are arranged at
such positions that the elastic guide members 20 do not interfere
with both the ends of the roller main body of the conveyance roller
9. More specifically, the conveyance guide unit according to the
embodiment is constituted by one conveyance roller 9 and two
elastic guide members 20 on both the sides of the conveyance roller
9. Each of the elastic guide members 20 has a band-like shape one
end of which is a fixed end 21 supported by an apparatus main body
housing or the like (not shown) through a bracket and the other end
of which is an elastically flexible free end 22.
[0029] As shown in FIGS. 3A and 3B, the original document 1 sent
from the registration rollers 7 is conveyed to the U-shaped path 11
by a switching operation by the switching lever 8 and goes to the
curved portion (see FIG. 3A). The free end 22 of the elastic guide
member 20 is elastically bent by contact force of the original
document 1 inserted between the conveyance roller 9 to escape to an
outside indicated by an arrow in FIG. 3B.
[0030] As is apparent from FIG. 3A, the free end 22 of the elastic
guide member 20 is set in an ordinary state in which the free end
22 is slightly bent inward from the surface level of the roller
main body 9d of the conveyance roller 9 and overlaps the roller
main body 9d without interfering therewith. More specifically, the
elastic guide member 20 is not brought into contact with the outer
peripheral surface of the roller main body 9d. A part of the
elastic guide member 20 is located closer to the roller rotating
shaft 9c than a virtual surface obtained by extending the outer
peripheral surface of the roller main body 9d in the axial
direction of the conveyance roller 9. The original document 1 is
interposed between the free end 22 of the elastic guide member 20
and the conveyance roller 9 to escape to the outside by elastically
transforming the free end 22. Therefore, the conveyed sheet is
sandwiched between the conveyance roller 9 and the plurality of
elastically transformed elastic guide member 20. The original
document is brought into press contact with the outer peripheral
surface of the roller main body 9d by elastic force of the elastic
guide member 20.
[0031] In this case, the free end of the elastic guide member is
set in an ordinary state in which the free end is bent inward from
the surface level of the roller main body 9d without interfering
with both the ends of the roller main body 9d of the conveyance
roller 9. This is because the free end 22 is slightly overlapped on
the conveyance roller 9 to effectively apply appropriate
press-contact force to an area of the original document 1, which is
longer and wider than an area obtained when both the members are in
point contact with each other at a surface without being
overlapped, depending on the thickness of the original document 1
in cooperation with the roller main body 9d.
[0032] Even though impact generated when the original document 1
sent between the conveyance roller 9 and the elastic guide members
20 is considerably large, the free end 22 of the elastic guide
member 20 is elastically bent to escape outside. For this reason,
the original document 1 can be effectively prevented from being
jammed. At this time, while the original document 1 is sent between
the conveyance roller 9 and the elastic guide members 20, the
elastic guide members 20 is appropriately elastically transformed
to absorb press-contact force received by the roller main body 9d,
so that the press-contact force is not excessive. When the original
document 1 is not sent between both the members, the elastic guide
members 20 do not interfere with the conveyance roller 9. For this
reason, the press-contact force received by the conveyance roller 9
is nothing. Regardless of the presence/absence of the original
document, unlike in a conventional technique, a motor output need
not be set to be large.
[0033] When the number of members in the apparatus according to the
embodiment is compared with the number of members in the apparatus
disclosed in Japanese Patent Application Laid-open No. 10-181929,
one elastic guide member 20 functions as a biasing spring and a
roller holding holder disclosed in Japanese Patent Application
Laid-open No. 10-181929. For this reason, the number of members can
be considerably reduced, and the cost can be reduced accordingly.
According to the sheet conveyance apparatus according to the
embodiment, one of two opposing conveyance rollers is omitted, and
the remaining conveyance roller is caused to function in place of a
band-like flat elastic guide member to reduce a space of one
conveyance roller, so that the apparatus can be suppressed from
being increased in size.
Sheet Conveyance Apparatus--Second Embodiment
[0034] FIG. 4 shows a second embodiment of the present invention
which is also called a modification of the first embodiment. In the
embodiment, when a combination of a conveyance roller and an
elastic guide member is defined as one conveyance guide unit, a
plurality of conveyance guide units are aligned in a direction
orthogonally crossing a conveyance direction. More specifically, a
structure in which two conveyance guide units each constituted by
one conveyance roller 9 and two elastic guide members 20 are
horizontally arranged, namely, arranged in a direction orthogonally
crossing a sheet conveyance direction A is formed. In this manner,
when the two conveyance guide units are horizontally arranged and
used, the conveyance guide units can be in contact with the
original document 1 in a wide area to effectively improve the
conveyability of the original document. Shafts 9c of the two
conveyance rollers 9 are common.
[0035] As the first and second embodiments described above, the
conveyance guide unit has an structure in which one of the outside
of the conventional opposing two conveyance roller 9 (see FIG. 8)
is caused to function as a roller in place of the bonded-like
elastic guide member 20. Therefore a fixed size L1 of the overall
apparatus can be reduced compound to a fixed size L2 to efficiently
suppress the increase in size of the apparatus.
Sheet Conveyance Apparatus--Third Embodiment
[0036] FIGS. 5 and 6 show a third embodiment according to the
present invention. In this embodiment, in order to give a compact
low-conveyance-load structure to the original document conveyance
mechanism described in the first embodiment in FIG. 1, external one
of two opposing discharge rollers 10 is omitted, and the remaining
discharge roller 10 is built in a structure as a part of a
conveyance guide unit. When two conveyance rollers are arranged on
upstream and downstream sides, an elastic guide member is fixed and
supported at the center of the band-like shape, and free ends at
both the ends of the elastic guide member are caused to face the
upstream and downstream sides of the conveyance 10026088 rollers.
More specifically, in this case, both the ends of an elastic guide
member 30 serve as elastically flexible free ends 31a and 31b. The
free end 31a on one end side is a part cooperated with the
conveyance roller 9, and the free end 31b on the other end side is
a part cooperated with the discharge roller 10.
[0037] In the third embodiment, a fixed size L1 of the overall
apparatus can be reduced, and the external discharge roller 10 is
omitted, so that a fixed size H of the overall apparatus in the
height direction can be reduced.
[0038] In this case, a total of four elastic guide members 30 for
the two conveyance guide units are arranged. However, the elastic
guide members 30 are connected and coupled to each other at the
respective central portions by a connection 32 having a long bar
shape to form a single-piece product, so that assembling property
of the apparatus is dramatically improved.
Sheet Conveyance Apparatus--Fourth Embodiment
[0039] In the first to third embodiments, one conveyance guide unit
is constituted by two elastic guide members 20 on both the sides of
one conveyance roller 9. However, as shown in FIG. 7, when one
conveyance roller 9 is constituted by two divided rollers 9a and
9b, as a matter of course, the major point of the present invention
can be applied.
(Image Reading Apparatus and Image Forming Apparatus)
[0040] On the other hand, when the sheet conveyance apparatus
according to each of the embodiments is built in an image reading
apparatus and equipped, a compact space-saving image reading
apparatus which transmits image information of an original document
scanned by a sheet conveyance apparatus to an external information
processing machine can be realized. When the sheet conveyance
apparatus according to each of the embodiments is built in a
copying machine or a facsimile machine and equipped, image
information scanned by the sheet conveyance apparatus is received
and printed out by an image forming unit. More specifically, when a
sheet is, for example, an original document, image information
recorded on the original document is loaded on the sheet conveyance
apparatus, and an image is formed by the image forming unit based
on the loaded image information, printed out, subjected to other
processes. In addition, when the sheet conveyance apparatus is
built in a printer, a compact space-saving image forming apparatus
which prints image information on a print sheet or the like
conveyed by the sheet conveyance apparatus according to the present
invention is realized.
[0041] A combination of a conveyance roller and an elastic guide
member in the sheet conveyance apparatus has a minimum number of
members, and the combination can be fitted into a limited member
space in the main bodies of the image reading apparatus and the
image forming apparatus. Therefore, the number of parts in the
sheet conveyance apparatus is suppressed to make it possible to
simplify the structure. The sheet conveyance apparatus can
contribute to effective utilization of a member storage space of
the image forming apparatus main body to also suppress paper jam of
an original correlatively to the simplification of the structure of
the sheet conveyance apparatus. For this reason, the overall
processing ability of the image reading apparatus and the image
forming apparatus can be assured advantageously.
[0042] The sheet conveyance apparatuses according to the first to
fourth embodiments and the embodiment of the image forming
apparatus equipped with the sheet conveyance apparatuses are
explained. However, the present invention is not limited to these
embodiments without departing from the spirit and scope of the
invention, and other embodiments, combinations thereof, and
applications can be applied.
[0043] This application claims the benefit of priority from the
prior Japanese Patent Application No. 2005-031440 filed on Feb. 8,
2005 the entire contents of which are incorporated by reference
herein.
* * * * *