U.S. patent application number 11/846316 was filed with the patent office on 2008-03-06 for sheet separation method, sheet separation mechanism and sheet feeder.
This patent application is currently assigned to NEC CORPORATION. Invention is credited to Takashi OKI.
Application Number | 20080054547 11/846316 |
Document ID | / |
Family ID | 38896124 |
Filed Date | 2008-03-06 |
United States Patent
Application |
20080054547 |
Kind Code |
A1 |
OKI; Takashi |
March 6, 2008 |
SHEET SEPARATION METHOD, SHEET SEPARATION MECHANISM AND SHEET
FEEDER
Abstract
Disclosed is a sheet separation method for separating a sheet
one by one from a bundle of the sheets and feeding the separated
sheet to a next processing step, including: suctioning an edge part
of the sheet and pulling the suctioned edge part from the bundle as
if to turn over the suctioned edge part; separating the sheet from
the bundle, the edge part of the sheet being suctioned and pulled;
and conveying the sheet separated from the bundle in a
predetermined direction. A sheet separation mechanism and a sheet
feeder are also disclosed.
Inventors: |
OKI; Takashi; (Tokyo,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
NEC CORPORATION
Tokyo
JP
|
Family ID: |
38896124 |
Appl. No.: |
11/846316 |
Filed: |
August 28, 2007 |
Current U.S.
Class: |
271/12 |
Current CPC
Class: |
B65H 2301/4233 20130101;
B65H 3/0825 20130101; B65H 3/32 20130101; B65H 3/50 20130101 |
Class at
Publication: |
271/12 |
International
Class: |
B65H 5/08 20060101
B65H005/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2006 |
JP |
231495/2006 |
Claims
1. A sheet separation method for separating a sheet one by one from
a bundle of the sheets and feeding the separated sheet to a next
processing step, comprising: suctioning an edge part of the sheet
and pulling the suctioned edge part from the bundle as if to turn
over the suctioned edge part; separating the sheet from the bundle,
the edge part of the sheet being suctioned and pulled; and
conveying the sheet separated from the bundle in a predetermined
direction.
2. The sheet separation method according to claim 1, wherein the
pulling includes: an up-and-down movement in which a suction head
that suctions the edge part moves in a vertical direction to a
surface of the bundle: and a twist movement in which the suction
head moves along a curved direction to the surface of the
bundle.
3. The sheet separation method according to claim 1, wherein the
separating includes inserting at least one separation roller which
moves along a surface of the bundle into a gap between the
suctioned edge part of the sheet and the bundle.
4. The sheet separation method according to claim 3, wherein a
plate-like guide provided to the separation roller prevents the
sheet separated from sagging.
5. The sheet separation method according to claim 3, wherein the
conveying includes rotating a conveying roller which sandwiches the
separated sheet with the separation roller.
6. A sheet separation mechanism for separating a sheet one by one
from a bundle of the sheets and feeding the separated sheet to a
next processing step, comprising: a suction/pulling unit including
a suction head for suctioning an edge part of the sheet and pulling
the suctioned edge part of the sheet apart from the bundle by a
twist movement of the suction head; a separation unit for
separating the sheet from the bundle, the edge part of the sheet
being suctioned and pulled by the suction head; and a conveying
unit for conveying the sheet separated from the bundle in a
predetermined direction.
7. The sheet separation mechanism according to claim 6, wherein the
suction/pulling unit comprises: an up-and-down movement unit which
moves the suction head to perform an up-and-down movement in a
vertical direction to a surface of the bundle; and a twist movement
unit which moves the suction head to perform a twist movement along
a curved direction to the surface of the bundle.
8. The sheet separation mechanism according to claim 6, wherein the
separation unit includes at least one separation roller which moves
along a surface of the bundle, and the sheet is separated from the
bundle by inserting the separation roller into a gap between the
edge part of the sheet suctioned and pulled by the suction/pulling
unit and the bundle.
9. The sheet separation mechanism according to claim 8, wherein the
separation roller includes a plate-like guide for preventing the
sheet separated from the bundle by the suction/pulling unit from
sagging.
10. The sheet separation mechanism according to claim 8, wherein
the conveying unit includes a conveying roller which sandwiches the
separated sheet with the separation roller, and the sheet separated
from the bundle is conveyed in a predetermined direction by a
rotation of the conveying roller on its axis.
11. A sheet separation mechanism for separating a sheet one by one
from a bundle of the sheets and feeding the separated sheet to a
next processing step, comprising: suction/pulling means including a
suction head for suctioning an edge part of the sheet and pulling
the suctioned edge part of the sheet apart from the bundle by a
twist movement of the suction head; separation means for separating
the sheet from the bundle, the edge part of the sheet being
suctioned and pulled by the suction head; and conveying means for
conveying the sheet separated from the bundle in a predetermined
direction.
12. A sheet feeder comprising a sheet conveying mechanism which
conveys a bundle of sheets and a sheet separation mechanism which
separates the sheet one by one from the bundle that is conveyed to
an end part of the sheet conveying mechanism and feeds the
separated sheet to a next processing step, wherein the sheet
separation mechanism comprises: a suction/pulling unit including a
suction head for suctioning an edge part of the sheet and pulling
the suctioned edge part of the sheet apart from the bundle by a
twist movement of the suction head; a separation unit for
separating the sheet from the bundle, the edge part of the sheet
being suctioned and pulled by the suction head; and a conveying
unit for conveying the sheet separated from the bundle in a
predetermined direction.
13. The sheet feeder according to claim 12, wherein the sheet
conveying mechanism comprises: an upright position
maintaining/conveying unit which conveys the bundle placed on a
mounting table toward the sheet separation mechanism while
maintaining an upright position of the bundle; and a posture
controlling/conveying unit which controls a posture of the bundle
before reaching the sheet separation mechanism while conveying the
bundle toward the sheet separation mechanism.
Description
RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese patent application No. 2006-231495, filed on
Aug. 29, 2006, the disclosure of which is incorporated herein in
its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a sheet separation method
which separates a sheet one by one from a bundle of sheets and a
sheet separation mechanism and moreover, relates to a sheet feeder
having such sheet separation mechanism.
[0004] 2. Description of the Related Art
[0005] A sheet separation mechanism which separates a sheet one by
one from a bundle of sheets is known. These sheets are for example,
postal matters such as postcards, letters and envelopes. Such sheet
separation mechanism feeds a separated sheet to a processing step
or a processing apparatus in a succeeding stage (i.e. next stage).
For example, a sheet feeder shown in FIG. 18 includes a mounting
table 101, a feeding conveyor 102 and a sheet separation mechanism
103.
[0006] The mounting table 101 is a table on which a bundle 10 of
sheets 11 is placed in an upright position. The feeding conveyor
102 conveys the bundle 10 of sheets 11 placed on the mounting table
101 toward a next stage. The sheet separation mechanism 103
separates the sheet 11 one by one from the bundle 10 that has been
conveyed to an end part of the feeding conveyor 102 and feeds the
separated sheet 11 to a processing apparatus in the stage.
[0007] In such sheet feeder, a posture of the bundle 10 of sheets
11 placed on the mounting table 101 is maintained in an upright
position by a compartment 104 provided for the feeding conveyor
102. The bundle 10 is conveyed toward the sheet separation
mechanism 103 by the compartment 104 and a bottom belt 105 (i.e. in
a direction of an arrow D11 in FIG. 18) while keeping the upright
posture. When the bundle 10 reaches the sheet separation mechanism
103, the sheets 11 are suctioned in order, from a top sheet, by a
vacuum suction chamber 107 via a suction belt 106 having a
plurality of through-holes therein. The suctioned sheet 11 is fed
one by one in a predetermined conveying direction (in a direction
of an arrow D12 in FIG. 18) according to a revolution of the
suction belt 106.
[0008] However, in the sheet separation mechanism 103 employing
such suction belt, if the bundle 10 includes the sheets 11 which
are attached firmly to each other, it is quite likely that the
sheets 11 cannot be separated one by one. In such case, a bundle
including two or more sheets 11 is fed to a processing apparatus in
a next stage. For example, when the sheets 11 whose surface is
vinyl-coated are stacked, the sheets 11 are firmly adhered to each
other. In the above mentioned related art, since sheets cannot be
properly separated through a suction/conveying operation of the
suction belt 106, a plurality of sheets are simultaneously fed to a
next stage.
[0009] Accordingly, as a further related art, for example, another
sheet separation mechanism is disclosed in Japanese Patent
Application Laid-Open No. Sho 63(1988)-106245 (the U.S. counterpart
application thereof is U.S. Pat. No. 4,815,723). The sheet
separation mechanism includes a suction/pulling unit (i.e. capture
unit), a separation unit (i.e. detachment unit) and a conveying
unit. The suction/pulling unit sucks and pulls an edge part of a
sheet apart from a bundle of sheets using a movable suction head
(i.e. sucker). The separation unit separates a sheet whose edge
part has been pulled apart from the bundle. The conveying unit
conveys the sheet separated from the bundle toward a processing
unit in a next stage. Since such sheet separation mechanism
suctions an edge part of a sheet to pull the sheet apart from the
bundle, the sheet separation mechanism has a good performance for
separating for a sheet compared with a sheet separation mechanism
employing a suction belt.
SUMMARY OF THE INVENTION
[0010] However, a suction head of a sheet separation mechanism of
such related art only moves linearly in a vertical direction to a
surface of a sheet. Therefore, even when such suction head is used,
a sheet is not separated from a bundle of sheets if edge parts of
the sheets are strongly attached to each other.
[0011] The present invention was made to solve such technical
problem. An object of the present invention is to provide a sheet
separation method, a sheet separation mechanism, and a sheet feeder
in which a sheet can be certainly separated one by one even when
stacked sheets are firmly contacted each other.
[0012] The present invention provides a sheet separation method for
separating a sheet one by one from a bundle of the sheets and
feeding the separated sheet to a next processing step, including:
suctioning an edge part of the sheet and pulling the suctioned edge
part from the bundle as if to turn over the suctioned edge part;
separating the sheet from the bundle, the edge part of the sheet
being suctioned and pulled; and conveying the sheet separated from
the bundle in a predetermined direction.
[0013] Further, the present invention provides a sheet separation
mechanism for separating a sheet one by one from a bundle of the
sheets and feeding the separated sheet to a next processing step,
including: a suction/pulling unit including a suction head for
suctioning an edge part of the sheet and pulling the suctioned edge
part of the sheet apart from the bundle by a twist movement of the
suction head; a separation unit for separating the sheet from the
bundle, the edge part of the sheet being suctioned and pulled by
the suction head; and a conveying unit for conveying the sheet
separated from the bundle in a predetermined direction.
[0014] Further, the present invention provides a sheet feeder
including a sheet conveying mechanism which conveys a bundle of
sheets and a sheet separation mechanism which separates the sheet
one by one from the bundle that is conveyed to an end part of the
sheet conveying mechanism and feeds the separated sheet to a next
processing step, wherein the sheet separation mechanism including:
a suction/pulling unit including a suction head for suctioning an
edge part of the sheet and pulling the suctioned edge part of the
sheet apart from the bundle by a twist movement of the suction
head; a separation unit for separating the sheet from the bundle,
the edge part of the sheet being suctioned and pulled by the
suction head; and a conveying unit for conveying the sheet
separated from the bundle in a predetermined direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Exemplary features and advantages of the present invention
will become apparent from the following detailed description when
taken with the accompanying drawings in which:
[0016] FIG. 1 is a plan view of a sheet feeder according to an
exemplary embodiment of the present invention.
[0017] FIG. 2 is a front view of the sheet feeder according to the
exemplary embodiment of the present invention.
[0018] FIG. 3 is a plan view showing a sheet conveying mechanism in
a conveying state with maintaining an upright position in the
exemplary embodiment of the present invention.
[0019] FIG. 4 is a front view showing the sheet conveying mechanism
in a conveying state with maintaining an upright position in the
exemplary embodiment of the present invention.
[0020] FIG. 5 is a plan view showing the sheet conveying mechanism
in a conveying state with a posture control in the exemplary
embodiment of the present invention.
[0021] FIG. 6 is a front view showing the sheet conveying mechanism
in a conveying state with a posture control in the exemplary
embodiment of the present invention.
[0022] FIG. 7A is a plan view showing a sheet separation mechanism
(at the beginning of a suction/pulling step) in the exemplary
embodiment of the present invention.
[0023] FIG. 7B is a cross sectional view showing a schematic cross
section taken along the line VIIB-VIIB viewing from an arrow
direction in FIG. 7A.
[0024] FIG. 8A is a plan view showing the sheet separation
mechanism (at the beginning of a separation step) in the exemplary
embodiment of the present invention.
[0025] FIG. 8B is a cross sectional view showing a schematic cross
section taken along the line VIIIB-VIIIB viewing from an arrow
direction in FIG. 8A.
[0026] FIG. 9A is a plan view showing the sheet separation
mechanism (during the separation step) in the exemplary embodiment
of the present invention.
[0027] FIG. 9B is a cross sectional view showing a schematic cross
section taken along the line IXB-IXB viewing from an arrow
direction in FIG. 9A.
[0028] FIG. 10A is a plan view showing the sheet separation
mechanism (at the beginning of a conveying step) in the exemplary
embodiment of the present invention.
[0029] FIG. 10B is a cross sectional view showing a schematic cross
section taken along the line XB-XB viewing from an arrow direction
in FIG. 10A.
[0030] FIG. 11 is a plan view showing the sheet separation
mechanism (during an original position returning step) in the
exemplary embodiment of the present invention.
[0031] FIG. 12 is a plan view showing an example of a suction head
operation mechanism in the exemplary embodiment of the present
invention.
[0032] FIG. 13 is a figure viewing from an arrow direction at a
position of the line XIII-XIII in FIG. 12.
[0033] FIG. 14 is a cross sectional view showing a schematic cross
section taken along the line XIV-XIV viewing from an arrow
direction in FIG. 13.
[0034] FIG. 15 is a partial side view showing the suction head
operation mechanism in the exemplary embodiment of the present
invention.
[0035] FIG. 16 is a partial front view showing the suction head
operation mechanism in normal state in the exemplary embodiment of
the present invention.
[0036] FIG. 17 is a partial front view showing the suction head
operation mechanism in twist movement state in the exemplary
embodiment of the present invention.
[0037] FIG. 18 is a front view showing a related art of a sheet
feeder.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0038] Exemplary embodiments of the present invention will now be
described in detail in accordance with the accompanying
drawings.
(A Sheet Feeder)
[0039] FIG. 1 is a plan view of a sheet feeder in an exemplary
embodiment according to the present invention. FIG. 2 is a front
view of the sheet feeder in the exemplary embodiment according to
the present invention.
[0040] As shown in FIG. 1 and FIG. 2, a sheet feeder in the
exemplary embodiment according to the present invention includes a
sheet conveying mechanism 20 and a sheet separation mechanism 30.
The sheet conveying mechanism 20 conveys a bundle 10 of sheets 11,
placed in an upright position, toward the sheet separation
mechanism 30 (in a direction of an arrow D1 in FIG. 1). The sheet
separation mechanism 30 separates a sheet 11 one by one from the
bundle 10 that is conveyed to an end part of the sheet conveying
mechanism 20 and feeds the separated sheet 11 to a processing step
or a processing apparatus (not shown) in a next stage (in a sheet
feeding direction of an arrow D2 in FIG. 1).
(A Sheet Conveying Mechanism)
[0041] First, the sheet conveying mechanism 20 will be described
with reference to FIG. 3 to FIG. 6. FIG. 3 is a plan view showing
the sheet conveying mechanism 20 for conveying a bundle 10 of
sheets 11 in an upright position in the exemplary embodiment of the
present invention. FIG. 4 is a front view showing the sheet
conveying mechanism 20 for conveying the bundle 10 in an upright
position in the exemplary embodiment. FIG. 5 is a plan view showing
the sheet conveying mechanism 20 in a conveying state with a
posture control in the exemplary embodiment. FIG. 6 is a front view
showing the sheet conveying mechanism 20 in a conveying state with
a posture control in the exemplary embodiment.
[0042] As shown in FIG. 3 to FIG. 6, the sheet conveying mechanism
20 includes a mounting table 21, an end plate 22, an upright
position maintaining/conveying unit 23 and a posture
controlling/conveying unit 24. The mounting table 21 is a table on
which the bundle 10 of sheets 11 is placed in an upright position.
The end plate 22 moves in a direction of an arrow D1 and applies a
pressure to the bundle 10 of sheets 11 to convey it, while keeping
a posture of the bundle 10.
[0043] The upright position maintaining/conveying unit 23 conveys
the bundle 10 in the direction of the arrow D1 while keeping the
bundle 10 in an upright position. The upright position
maintaining/conveying unit 23 includes conveying belts 25 having
teeth engaged with a bottom end of the sheet 11. Two conveying
belts 25 are arranged side by side along the mounting table 21, and
the belts 25 are driven at almost the same speed as that of the end
plate 22. By the driving operation, the bundle 10 of sheets 11 is
conveyed to the posture controlling/conveying unit 24 while
maintaining an upright position.
[0044] The posture controlling/conveying unit 24 controls a posture
of the bundle 10 which is conveyed to an end part of the upright
position maintaining/conveying unit 23 while conveying the bundle
10 toward the sheet separation mechanism 30. The posture
controlling/conveying unit 24 includes two conveying belts 26
having teeth engaged with a bottom end of the sheet 11 and angle
detection sensors 27 which detect a posture of the bundle 10 of the
sheets 11. The conveying belts 26 are arranged side by side so that
the bundle 10 of the sheet 11 can be smoothly caught from the
conveying belts 25. The angle detection sensors 27 are arranged at
both sides of a conveying path of the posture controlling/conveying
unit 24 to detect an angle of the sheets 11. For example, in case
that a target angle in a posture control of the sheets 11 is 30
degrees, three angle detection sensors 27 are arranged on a
straight line at an angle of 30 degrees with respect to a conveying
direction (i.e. arrow direction D1) of the sheets 11 in FIG. 4. An
angle detection of the sheets 11 is performed based on a detection
timing of the angle detection sensors 27.
[0045] In the sheet conveying mechanism 20 mentioned above, the
bundle 10 of sheets 11 is placed on the conveying belts 25 of the
mounting table 21 in an upright position as shown in FIG. 3 and
FIG. 4. Then, the end plate 22 and the conveying belts 25 convey
the bundle 10 of sheets 11 toward a next stage (direction D1) while
maintaining an upright position.
[0046] Next, a conveyance of the bundle 10 of sheets 11 is taken
over from the conveying belts 25 to the conveying belts 26 as shown
in FIG. 5 and FIG. 6. Because the conveying belts 26 drive at a
higher speed than the conveying belts 25 and the end plate 22, the
bundle 10 is further conveyed while changing an angle of an upright
position. At the time, the angle of the bundle 10 is detected by
the angle detection sensors 27 and a driving speed of the conveying
belt 25 (or 26) is controlled by feedback-control. By performing
such control, the angle of the bundle 10 can be adjusted to an
arbitrary value. For example, in the exemplary embodiment, a
driving speed of the conveying belt 25 (or 26) is
feedback-controlled so that the target angle of the bundle 10 at an
end part of the conveying belt 26 becomes 30 degrees.
(A Sheet Separation Mechanism)
[0047] Next, the sheet separation mechanism 30 will be described
with reference to FIG. 7A to FIG. 11. FIG. 7A is a plan view
showing the sheet separation mechanism 30 at the beginning of a
suction/pulling step in the exemplary embodiment. FIG. 7B is a
cross sectional view showing a schematic cross section taken along
the line VIIB-VIIB viewing from an arrow direction in FIG. 7A. FIG.
8A is a plan view showing the sheet separation mechanism 30 at the
beginning of a separation step in the exemplary embodiment. FIG. 8B
is a cross sectional view showing a schematic cross section taken
along the line VIIIB-VIIIB viewing from an arrow direction in FIG.
8A. FIG. 9A is a plan view showing the sheet separation mechanism
30 during the separation step in the exemplary embodiment. FIG. 9B
is a cross sectional view showing a schematic cross section taken
along the line IXB-IXB viewing from an arrow direction in FIG. 9A.
FIG. 10A is a plan view showing the sheet separation mechanism 30
at the beginning of a conveying step in the exemplary embodiment.
FIG. 10B is a cross sectional view showing a schematic cross
section taken along the line XB-XB viewing from an arrow direction
in FIG. 10A. FIG. 11 is a plan view showing the sheet separation
mechanism during an original position returning step in the
exemplary embodiment.
[0048] As shown in those drawings, the sheet separation mechanism
30 includes a suction/pulling unit 31, a separation unit 32 and a
conveying unit 33. The suction/pulling unit 31 suctions an edge
part of the sheet 11 to pull the edge part apart from the bundle
10. The separation unit 32 completely separates the sheet 11 whose
edge part is pulled from the bundle 10. The conveying unit 33
conveys the sheet 11 separated from the bundle 10 to a processing
step or a processing apparatus (not shown) in a next stage.
[0049] The suction/pulling unit 31 includes a suction head 34, an
arm 35 and a suction head operation mechanism 40 (not shown in FIG.
7A to FIG. 11). The suction head 34 is connected to a vacuum source
(not shown) to suction an edge part of the sheet 11. The arm 35
moves the suction head 34 in a predetermined direction. The suction
head operation mechanism 40 drives the suction head 34 via the arm
35 to perform a necessary operation. The suction head operation
mechanism 40 is described in detail below. The arm 35 not only move
the suction head 34 in a vertical direction to a surface of the
bundle 10 but also move the suction head 34 along a curved line to
tilt the suction head 34 with respect to the surface of the bundle
10 as if to turn over the suctioned edge part of the sheet to be
separated. Because of such movements of the suction head 34, an
only suctioned edge part of the sheet 11 is bent, curled or curved.
That is, the suctioned edge part of the sheet is pulled apart from
the bundle 10 to generate a gap between the (first positioned)
sheet 11 and the bundle 10 (i.e., the remaining sheets). For
example, the arm 35 moves the suction head 34 in a direction of an
arrow D4 shown in FIG. 7B. Such operation can be enabled by the
suction head operation mechanism 40 explained in detail below.
[0050] The separation unit 32 includes a separation roller 36. The
separation roller 36 is inserted into a gap between the sheet 11
that is partially separated by the suction/pulling unit 31 and a
remaining part of the bundle 10 by revolution of the separation
roller 36. Accordingly, the only one sheet 11 is completely
separated from the bundle 10.
[0051] In the exemplary embodiment, three separation rollers 36a to
36c are arranged so as to protrude radially from a rotatable pulley
37. The separation rollers 36a to 36c are arranged side by side at
a predetermined interval in a rotation direction of the pulley 37
(direction of an arrow D3 in the drawings). The separation rollers
36a to 36c revolve around the pulley 37 and may also rotate about
each rotation axis. When the separation rollers 36a to 36c are
inserted in turn into a gap between the sheet 11 that is partially
pulled by the suction head 34 and the bundle 10, the sheet 11 can
be completely separated from the bundle 10. Further, a plate-like
conveyance guide 38 for preventing sagging (i.e. drooping) of the
separated sheet 11 is provided for the separation roller 36c that
is the last separation roller.
[0052] The conveying unit 33 includes a conveying roller 39. As
mentioned below, the conveying roller 39 rotates on its axis while
the sheet 11 is located between the conveying roller 39 and the
separation roller 36c. Thereby, a rotation force of the conveying
roller 39 is transmitted to the sheet 11 separated from the bundle
10 and the separated sheet 11 is conveyed toward a processing step
or a processing apparatus in a next stage.
[0053] Further, the sheet separation mechanism 30 described above
can be applied to a bundle of sheets with various angle postures
including a horizontal posture and a vertical posture by adjusting
an angle of a revolution plane of the separation rollers 36a to 36c
and a movement mode or direction of the suction head 34. According
to an angle detection of the sheet 11 in the sheet conveying
mechanism 20, an angle of a revolution plane of the separation
rollers 36a to 36c and a movement mode or direction of the suction
head 34 may be adjusted automatically. Because of such adjustments,
separating performance of the sheet separation mechanism 30 is
further improved.
(A Sheet Separation Method)
[0054] Next, a sheet separation method will be described with
reference to FIG. 7A to FIG. 11. In the sheet separation mechanism
30, first, as shown in FIG. 7A and FIG. 7B, an edge part of a top
sheet of the sheet 11 of the bundle 10 is suctioned by the suction
head 34. After that, the suction head 34 moves the suctioned edge
part of the sheet 11 so as to bend the edge part in a direction
shown as arrow D4 in FIG. 7B, while lifting the edge part up in a
vertical direction to a surface of the bundle 10. Further, a
movement in which the suction head 34moves along a curved line
indicated as the arrow D4 in FIG. 7B is called as "twist movement"
here. By the twist movement of the suction head 34, as shown in
FIG. 8A and FIG. 8B, an edge part of the sheet 11 is pulled apart
from the bundle 10 (a suction/pulling step).
[0055] Next, as shown in FIG. 8A to FIG. 9B, the pulley 37 rotates
in a direction illustrated as an arrow D3. As a result, the
separation rollers 36a to 36c are inserted in turn into a gap
between the sheet 11 that is partially pulled and the bundle 10 and
accordingly, the sheet 11 is gradually separated from the bundle
10. When the separation roller 36c that is the last separation
roller reaches a location opposed to the conveying roller 39 as
shown in FIG. 10A, a rotation of the pulley 37 stops (a separation
step).
[0056] Next, as shown in FIG. 10B, suction by the suction head 34
stops to release the separated sheet 11, and also the conveying
roller 39 rotates on its axis (rotation in a direction of an arrow
D5). As a result, the separated sheet 11 which is sandwiched
between the conveying roller 39 and the separation roller 36c is
conveyed toward a next stage (in a direction of an arrow D2). At
the time, sagging of the separated sheet 11 is prevented by the
conveyance guide 38 (a conveying step).
[0057] When a conveyance of the separated sheet 11 is completed,
the pulley 37 rotates again as shown in FIG. 11, and the separation
rollers 36a to 36c are returned to an original position (FIG. 7A)
(an original position returning step).
(A Suction Head Operation Mechanism)
[0058] Next, a suction head operation mechanism 40 which is an
actual operation mechanism of the suction head 34 will be described
with reference to FIG. 12 to FIG. 17. FIG. 12 is a plan view
showing an example of the suction head operation mechanism 40 in
the exemplary embodiment. FIG. 13 is a figure viewing from an arrow
direction at a position of the line XIII-XIII in FIG. 12. FIG. 14
is a cross sectional view showing a schematic cross section taken
along the line XIV-XIV viewing from an arrow direction in FIG. 13.
FIG. 15 is a partial side view showing the suction head operation
mechanism 40 in the exemplary embodiment. FIG. 16 is a partial
front view showing the suction head operation mechanism 40 in
normal state in the exemplary embodiment. FIG. 17 is a partial
front view showing the suction head operation mechanism 40 in twist
movement state in the exemplary embodiment.
[0059] The suction head operation mechanism 40 shown in above
drawings includes a twist movement unit which controls the suction
head 34 to perform the above-mentioned twist movement and an
up-and-down movement unit which controls the suction head 34 to
perform an up-and-down movement.
[0060] The twist movement unit includes a swinging link 41, a
spindle 42, a slider 43 and an air cylinder 44. One end of the
swinging link 41 supports the suction head 34 via the arm 35. The
other end of the swinging link 41 is connected to the air cylinder
44. The slider 43 swingably supports the swinging link 41 via the
spindle 42 parallel to the arm 35. The air cylinder 44 is provided
between the slider 43 and the swinging link 41. As shown in FIG. 16
and FIG. 17, when the air cylinder 44 performs expanding movement,
force of the expanding movement transmits to the other end of the
swinging link 41. Then, the swinging link 41 swings about the
spindle 42 that serves as a supporting point (in a direction of an
arrow D7 in FIG. 16), and the twist movement of the suction head 34
is performed.
[0061] The up-and-down movement unit includes a guide rail 45, a
base 46, a servo motor 47, a pulley 48 and a connection rod 49. The
guide rail 45 is provided on the base 46 to guide an up-and-down
slide operation of the slider 43. The base 46 supports up-and-down
slidably the slider 43 via the guide rail 45.
[0062] The servo motor 47 is provided below the base 46. The pulley
48 is connected to a drive shaft of the servo motor 47 and is
rotated within a predetermined angle range according to a rotation
of the drive shaft. The connection rod 49 connects the pulley 48
and one end of the slider 43. When the servo motor 47 drives,
driving force thereof is transmitted to the slider 43 via the
pulley 48 and the connection rod 49 (in a direction of an arrow D6
in FIG. 13). As a result, the slider 43 slides up-and-down along
the guide rail 45 and the suction head 34 provided at an end of the
arm 35 moves up-and-down.
[0063] In the sheet separation mechanism and the sheet separation
method of the exemplary embodiment as mentioned above, the
suction/pulling unit 31 includes the suction head 34 which suctions
an edge part of the sheet 11 and the edge part of the sheet 11 is
partly separated from the bundle 10 by the twist movement of the
suction head 34. As a result, even when sheets 11 in the bundle 10
strongly adhere to each other, the sheet 11 can be certainly
separated one by one and stably fed to a next step.
[0064] The separation unit 32 includes the plurality of separation
rollers 36a to 36c which revolve around the pulley 37. The
separation rollers 36a to 36c are inserted in turn into a gap
between the sheet 11 that is partly pulled by the suction/pulling
unit 31 and the bundle 10. Accordingly, the only one sheet 11 is
separated from the bundle 10. Thus, the separation unit 32 of the
exemplary embodiment can separate the sheet 11 that is partly
pulled by the suction/pulling unit 31 from the bundle 10 quickly
and certainly.
[0065] The conveying unit 33 includes the conveying roller 39. The
sheet 11 is sandwiched between the separation roller 36c and the
conveying roller 39. The rotation force of the conveying roller 39
conveys and feeds the sheet 11 separated from the bundle 10 toward
a next stage (i.e. a processing apparatus in a next step). Thus, in
the exemplary embodiment, the separated sheet 11 can be certainly
conveyed and also a structure of the conveying unit 33 can be
simplified by utilizing the separation roller 36c for a part of the
conveying unit 33.
[0066] The exemplary embodiment described above can be applied to a
sheet feeder having a sheet separation mechanism. In particular, a
sheet separation mechanism of the exemplary embodiment is suitable
for a supply feeder of a large scale mail sorting apparatus, but
also it can be applied to a supply feeder which separates and
supplies a mail such as an ordinary postcard and a letter or a
supply feeder which separates and supplies other sheets.
[0067] As mentioned above, by employing the present invention, an
edge part of a sheet is suctioned by a suction head and the edge
part of the sheet is partly separated from a bundle of the sheets
by the twist movement of the suction head. Therefore, the sheet can
be certainly separated one by one from the bundle in which the
sheets strongly adhere to each other and the separated sheet is
stably fed to a next step.
[0068] The previous description of exemplary embodiments is
provided to enable a person skilled in the art to make and use the
present invention. Moreover, various modifications to these
exemplary embodiments will be readily apparent to those skilled in
the art, and the generic principles and specific examples defined
herein may be applied to other exemplary embodiments without the
use of inventive faculty. Therefore, the present invention is not
intended to be limited to the exemplary embodiments described
herein but is to be accorded the widest scope as defined by the
limitations of the claims and equivalents.
[0069] Further, it is noted that the inventor's intent is to retain
all equivalents of the claimed invention even if the claims are
amended during prosecution.
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