U.S. patent application number 11/802873 was filed with the patent office on 2007-12-27 for energy storing sheet feeder.
This patent application is currently assigned to Avision Inc.. Invention is credited to Hsin Hong Chen.
Application Number | 20070296139 11/802873 |
Document ID | / |
Family ID | 38872828 |
Filed Date | 2007-12-27 |
United States Patent
Application |
20070296139 |
Kind Code |
A1 |
Chen; Hsin Hong |
December 27, 2007 |
Energy storing sheet feeder
Abstract
A sheet feeder includes a separation roller, a friction roller,
a shaft and an energy storing element. The energy storing element
stores energy when the friction roller is driven by the separation
roller to rotate in the sheet-feeding direction and releases energy
to make the friction roller rotate in a direction opposite to the
sheet-feeding direction.
Inventors: |
Chen; Hsin Hong; (Jhunan
Township, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Avision Inc.
|
Family ID: |
38872828 |
Appl. No.: |
11/802873 |
Filed: |
May 25, 2007 |
Current U.S.
Class: |
271/121 |
Current CPC
Class: |
B65H 2301/44514
20130101; B65H 3/5261 20130101; B65H 5/062 20130101; B65H 2402/545
20130101 |
Class at
Publication: |
271/121 |
International
Class: |
B65H 3/52 20060101
B65H003/52 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2006 |
TW |
095122612 |
Claims
1. An energy storing sheet feeder for feeding and separating a
first sheet and a second sheet, which are stacked together, the
sheet feeder comprising: a separation roller rotating in a
sheet-feeding direction and driven by a driving device; a friction
roller, which may be rotated by the separation roller; a shaft,
which passes through the friction roller; and an energy storing
element for storing energy when the friction roller is driven by
the separation roller to rotate in the sheet-feeding direction and
for releasing energy to make the friction roller rotate in a
direction opposite to the sheet-feeding direction.
2. The sheet feeder according to claim 1, wherein the friction
roller has a first forwarding state, a reversing state and a second
forwarding state, wherein: in the first forwarding state, the
separation roller rotates the friction roller to feed the first
sheet alone or to feed the first sheet and the second sheet
simultaneously, and the friction roller drives the energy storing
element to make the energy storing element store the energy; in the
reversing state, the energy storing element releases the energy to
reverse the friction roller to push the second sheet away from a
nip between the friction roller and the separation roller; and in
the second forwarding state, the separation roller drives the
second/first sheet to make the second/first sheet rotate the
friction roller and thus make the energy storing element store the
energy.
3. The sheet feeder according to claim 1, wherein the shaft moves
relative to the rotating friction roller and the energy storing
element is disposed between the shaft and the friction roller.
4. The sheet feeder according to claim 1, wherein the shaft is
stationary relative to the rotating friction roller and the energy
storing element is connected to the shaft.
5. The sheet feeder according to claim 1, wherein the energy
storing element is a worm spring or a torsional spring.
6. The sheet feeder according to claim 5, wherein the energy
storing element is preloaded to store predetermined energy in
advance.
7. The sheet feeder according to claim 1, further comprising: a
force-applying mechanism for pushing the separation roller against
the friction roller.
8. The sheet feeder according to claim 7, wherein the energy
storing element is a worm spring or a torsional spring.
9. The sheet feeder according to claim 8, wherein the energy
storing element is preloaded to store predetermined energy in
advance.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The invention relates to a sheet feeder, and more
particularly to a sheet feeder, capable of storing energy.
[0003] 2. Related Art
[0004] An automatic document feeder may be used in an image
input/output apparatus, such as a scanner, a multi-function
peripheral, a copier or even a printer, to feed documents or sheets
one by one.
[0005] FIGS. 1 to 3 are schematic illustrations showing operations
of a conventional sheet feeder. Referring to FIGS. 1 to 3, the
conventional sheet feeder includes a separation roller 110, a
friction roller 120 and a torque limiter 130. The separation roller
110 is mounted on a rotating shaft 112, which may be a rotating
shaft of a motor. The friction roller 120 is mounted on a rotating
shaft 122, which may be a rotating shaft of another motor. The
torque limiter 130 connects the friction roller 120 to the rotating
shaft to provide a torsional force for restricting the rotation of
the friction roller 120.
[0006] As shown in FIG. 1, when the sheet-separating operation is
not performed yet, the separation roller 110 rotates clockwise to
rotate the friction roller 120 to feed the sheets S1 and S2, and
the undesired condition of multi-sheet feeding occurs. To solve
this problem, as shown in FIG. 2, the rotating shaft 122
continuously rotates the friction roller 120 clockwise through the
torque limiter 130 to push the sheet S2 out of the passageway
between the friction roller 120 and the separation roller 110.
Thus, the sheets may be separated.
[0007] As shown in FIG. 3, when only the sheet S2 is left, the
rotating shaft 112 rotates the separation roller 110 clockwise to
make the sheet S2 enter the passageway, and the friction force
between the sheet S2 and the friction roller 120 rotates the
friction roller 120 counterclockwise while the rotating shaft 122
rotates the torque limiter 130 clockwise. However, the torque for
the sheet S2 to rotate the friction roller 120 counterclockwise is
larger than the torque for the torque limiter 130 to rotate the
friction roller 120 clockwise. So, the sheet S2 drives the friction
roller 120 to rotate counterclockwise.
[0008] Thus, the conventional sheet feeder needs two power sources
and one torque limiter, and the sliding friction states are often
created between the friction roller, the torque limiter and the
rotating shaft. Consequently, the manufacturing cost is high and
the components tend to be worn to influence the subsequent
sheet-separating function.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the invention to provide an
energy storing sheet feeder, wherein only one power source in
conjunction with an energy storing element capable of storing and
releasing energy are used to make the sheet-separating operation
more reliable, and the cost of the sheet feeder and the wear
between rollers can be reduced effectively.
[0010] To achieve the above-identified object, the invention
provides an energy storing sheet feeder for feeding and separating
a first sheet and a second sheet, which are stacked together. The
sheet feeder includes a separation roller, a friction roller, a
shaft and an energy storing element. The separation roller rotates
in a sheet-feeding direction and driven by a driving device. The
friction roller may be rotated by the separation roller. The shaft
passes through the friction roller. The energy storing element
stores energy when the friction roller is driven by the separation
roller to rotate in the sheet-feeding direction and releases energy
to make the friction roller rotate in a direction opposite to the
sheet-feeding direction. The friction roller has a first forwarding
state, a reversing state and a second forwarding state. In the
first forwarding state of the friction roller, the separation
roller rotates the friction roller to feed the first sheet alone or
to feed the first sheet and the second sheet simultaneously, and
the friction roller drives the energy storing element to make the
energy storing element store the energy. In the reversing state of
the friction roller, the energy storing element releases the energy
to reverse the friction roller to push the second sheet away from a
nip between the friction roller and the separation roller. In the
second forwarding state of the friction roller, the separation
roller drives the second/first sheet to make the second/first sheet
rotate the friction roller and thus make the energy storing element
store the energy.
[0011] According to the sheet feeder of the invention, in which the
energy storage element is used to store the energy, the friction
roller reverses when the energy storage element releases the energy
when two sheets enter the nip between the friction roller and the
separation roller. Thus, one of the sheets close to the friction
roller may be ejected out of the passageway to prevent multiple
sheets from being fed. It is to be noted that the energy storing
element itself may have a clutch or be combined with a clutch so
that the friction roller continues rotating when the energy storing
element has stored the maximum energy.
[0012] Further scope of the applicability of the present invention
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0014] FIGS. 1 to 3 are schematic illustrations showing operations
of a conventional sheet feeder.
[0015] FIGS. 4 to 7 are schematic illustrations showing operations
of a sheet feeder according to a preferred embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present invention will be apparent from the following
detailed description, which proceeds with reference to the
accompanying drawings, wherein the same references relate to the
same elements.
[0017] FIGS. 4 to 7 are schematic illustrations showing operations
of a sheet feeder according to a preferred embodiment of the
invention. As shown in FIGS. 4 to 7, the energy storing sheet
feeder according to this embodiment feeds and separates a first
sheet S1 and a second sheet S2, which are stacked together. The
energy storing sheet feeder includes a separation roller 10, a
friction roller 20, a shaft 30 and an energy storing element 40.
The separation roller 10 is driven by a rotating shaft 14 of a
driving device 12 to rotate. The friction roller 20 may be rotated
by the separation roller 10 as well as the first sheet S1 or the
second sheet S2. The shaft 30 passes through the friction roller
20. The shaft 30 moves relative to the rotating friction roller 20
and the energy storing element 40 is disposed between the shaft 30
and the friction roller 20. Alternatively, the shaft 30 may be
stationary relative to the rotating friction roller 20 and the
energy storing element 40 is connected to the shaft 30. The energy
storing element 40 may be a worm spring or a torsional spring. The
energy storing element 40 stores energy when the friction roller 20
is driven by the separation roller 10 to rotate in the
sheet-feeding direction and releases energy to make the friction
roller 10 rotate in a direction opposite to the sheet-feeding
direction.
[0018] In order to make the energy storing element 40 store some
energy during the initial setting process, the energy storing
element 40 may be preloaded to store the predetermined energy. It
is to be noted that when the energy storing element 40 has stored
the maximum energy, no more energy can be stored in the energy
storing element 40. However, the action of the energy storing
element 40 would not impede the rotation of the friction roller 20
when a mechanism, such as a one-way clutch, is used.
[0019] The friction roller 20 has a first forwarding state, a
reversing state and a second forwarding state. In the first
forwarding state, as shown in FIG. 4, the separation roller 10
rotating clockwise drives the friction roller 20 to rotate
counterclockwise to feed the first sheet S1 or the first sheet S1
and the second sheet S2. At this time, the friction roller 20 also
drives the energy storing element 40 to make the energy storing
element 40 store the energy.
[0020] In the reversing state, that is, when the sheets S1 and S2
simultaneously enter a nip 60 between the friction roller 20 and
the separation roller 10, as shown in FIG. 5, the energy storing
element 40 releases the energy to reverse the friction roller 20
clockwise because the friction between the sheets S1 and S2 is
smaller than the friction between the sheet S2 and the friction
roller 20. Thus, the second sheet S2 can be pushed out of the nip
60 between the friction roller 20 and the separation roller 10, and
the state shown in FIG. 6 may be obtained. When the sheet is being
transported, the state may also be changed from that of FIG. 6 to
that of FIG. 5. Thus, the friction roller 20 may rotate clockwise
or counterclockwise intermittently to keep only one sheet in the
nip 60. In other words, the energy storing element releases the
energy to reverse the friction roller to push one of the sheets out
of the nip as long as two sheets enter the passageway.
[0021] In the second forwarding state, as shown in FIGS. 6 and 7,
the separation roller 10 drives the second/first sheet S2/S1 to
make the second/first sheet S2/S1 rotate the friction roller 20 to
make the energy storing element 40 store the energy.
[0022] In addition, the energy storing sheet feeder may further
include a spring or a force-applying mechanism 50 of a hydraulic
device, which pushes the separation roller 10 against the friction
roller 20. Alternatively, the weight of the separation roller 10
may be utilized to push the separation roller 10 against the
friction roller 20. Such a design makes the feeder be adapted to
the sheets with various thicknesses and immediately compensates for
the worn separation roller or the worn friction roller.
[0023] According to the sheet feeder of the invention, no torque
limiter has to be utilized, and the energy storing element is
utilized to achieve the advantage of reducing the cost and the size
effectively. Because only one single power source is used, the
feeder can be assembled in a simpler manner. Because rolling
friction states are created between the friction roller and the
separation roller and between the friction roller and the sheet,
the wear of the friction roller can be effectively reduced, and the
lifetime of the friction roller may be thus lengthened.
[0024] While the invention has been described by way of example and
in terms of a preferred embodiment, it is to be understood that the
invention is not limited thereto. To the contrary, it is intended
to cover various modifications. Therefore, the scope of the
appended claims should be accorded the broadest interpretation so
as to encompass all such modifications.
* * * * *