U.S. patent application number 12/103555 was filed with the patent office on 2009-10-15 for sheet separating mechanism of an auto sheet feeder and auto sheet feeder incorporating the same.
This patent application is currently assigned to FOXLINK IMAGE TECHNOLOGY CO., LTD.. Invention is credited to Chun-Kuan LEE, Wen-Sheng LIU, Shao-Yang WU.
Application Number | 20090256307 12/103555 |
Document ID | / |
Family ID | 41163319 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090256307 |
Kind Code |
A1 |
WU; Shao-Yang ; et
al. |
October 15, 2009 |
SHEET SEPARATING MECHANISM OF AN AUTO SHEET FEEDER AND AUTO SHEET
FEEDER INCORPORATING THE SAME
Abstract
An auto sheet feeder used for a device comprises an upper frame,
a pick roller and a sheet separating mechanism secured on the upper
frame. The sheet separating mechanism includes a bracket and a pair
of arms disposed on the bracket and spring-biased toward the pick
roller. A separator pad is disposed on the bracket and
spring-biased toward the pick roller. A press plate is positioned
on the bracket and presses against the separator pad. A torsion
spring mounted above the press plate has at least two coil
portions. Two adjacent ends of the coil portions extend toward the
same side and then joint each other to form a contact portion which
always props the upper frame. Two ends of the torsion spring have a
retaining arm respectively. The two retaining arms are opposite
each other and pivotally engage to two sides of the press plate
respectively. The torsion spring is compressed by the press plate
when the sheets push the separator pad and pushes the press plate
and the separator pad to be reposition after the lowermost one of
the sheets is separated.
Inventors: |
WU; Shao-Yang; (Hsinchu,
TW) ; LIU; Wen-Sheng; (Hsinchu, TW) ; LEE;
Chun-Kuan; (Hsinchu, TW) |
Correspondence
Address: |
WPAT, PC;INTELLECTUAL PROPERTY ATTORNEYS
2030 MAIN STREET, SUITE 1300
IRVINE
CA
92614
US
|
Assignee: |
FOXLINK IMAGE TECHNOLOGY CO.,
LTD.
Hsinchu
TW
|
Family ID: |
41163319 |
Appl. No.: |
12/103555 |
Filed: |
April 15, 2008 |
Current U.S.
Class: |
271/139 ;
271/121 |
Current CPC
Class: |
B65H 2402/541 20130101;
B65H 3/5238 20130101; B65H 2402/545 20130101 |
Class at
Publication: |
271/139 ;
271/121 |
International
Class: |
B65H 7/02 20060101
B65H007/02 |
Claims
1. A sheet separating mechanism for an auto sheet feeder having a
pick roller and an upper frame, the mechanism comprising: a
bracket; a pair of spring arms disposed on the bracket and
spring-biased toward the pick roller for maintaining a plurality of
sheets on the pick roller during transportation of the sheets; a
separator pad disposed on the bracket and spring-biased toward the
pick roller for cooperating with the pick roller to permit further
transportation of a lowermost sheet of the plurality of the sheets;
a press plate positioned on the bracket and pressing against the
separator pad; and a torsion spring mounted above the press plate
and having at least two coil portions spaced and opposite to the
adjacent coil portion, two adjacent ends of the coil portions
extending toward the same side and then jointing each other to form
a contact portion which always props the upper frame, two ends of
the torsion spring having a retaining arm respectively, the two
retaining arms pivotally engaging to two sides of the press plate
respectively; wherein the torsion spring is compressed by the press
plate when the sheets push the separator pad to detach from the
pick roller and pushes the press plate and the separator pad to be
reposition after the lowermost one of the sheets is separated.
2. The sheet separating mechanism of an auto sheet feeder as
claimed in claim 1, wherein the bracket further comprises a support
board, the bottom of the support board bending and extending
backward to form a prop board, two fixing pegs extending downward
from the bottom of the prop board, two fixing holes being defined
in the separator pad, the two fixing pegs being inserted into the
two fixing holes respectively so as to secure the separator pad on
the bracket.
3. The sheet separating mechanism of an auto sheet feeder as
claimed in claim 1, wherein the spring arms are part of a pick
spring mounted to the bracket, the pick spring further including a
spring press portion, a separator press portion being formed on the
surface of the separator pad, the spring press portion of the pick
spring pressing on the separator press portion.
4. The sheet separating mechanism of an auto sheet feeder as
claimed in claim 2, further comprising a press pad, the press pad
including a pad holder and a pad press portion, the backside of the
prop board of the bracket being dent to form a fixing groove, the
pad holder of the press pad being fixed in the fixing groove, the
pad press portion being pressed upon the sheets to prevent curling
of the sheets.
5. An auto sheet feeder for a device where separation of a single
sheet from a plurality of sheets is desired, the feeder comprising:
an upper frame; a pick roller; and a sheet separating mechanism
secured on the upper frame, wherein the sheet separating mechanism
comprising a bracket; a pair of spring arms disposed on the bracket
and spring-biased toward the pick roller for maintaining the
plurality of sheets on the pick roller during transportation of the
sheets; a separator pad disposed on the bracket and spring-biased
toward the pick roller for cooperating with the pick roller to
permit further transportation of a lowermost sheet of the plurality
of the sheets; a press plate positioned on the bracket and pressing
against the separator pad; and a torsion spring mounted above the
press plate and having at least two coil portions spaced and
opposite to the adjacent coil portion, two adjacent ends of the
coil portions extending toward the same side and then jointing each
other to form a contact portion which always props the upper frame,
two ends of the torsion spring having a retaining arm respectively,
the two retaining arms pivotally engaging to two sides of the press
plate respectively; wherein the torsion spring is compressed by the
press plate when the sheets push the separator pad to detach from
the pick roller and pushes the press plate and the separator pad to
be reposition after the lowermost one of the sheets is separated.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This present invention relates to an auto sheet feeder
applicable to an office device such as a printer, a copier and a
scanner, and more particularly to a sheet separating mechanism of
the auto sheet feeder and an auto sheet feeder having the same.
[0003] 2. The Related Art
[0004] A conventional auto sheet feeder is generally used in
various office devices such as a printer, a copier, a scanner and
the like, and it is highly desirable to separate single paper sheet
from a stack of paper sheets placed on an a paper feeding plate. So
a sheet separating mechanism is provided.
[0005] With reference to FIGS. 1 and 2, a conventional sheet
separating mechanism includes a pick roller 910, a separator pad
920, a press plate 930 and a spring 940. The press plate 930
includes a plate portion 932 pressing against the separator pad
920, a pair of connecting rods 934 extending upward from two ends
of the plate portion 932 and a pair of pivots 936 respectively
protruding outward from the two connecting rods 934. The two pivots
936 are pivotally mounted to an upper frame (not shown). One end of
the spring 940 is fastened on the middle of the plate portion 932
and the other end of the spring 940 resists on the upper frame. The
separator pad 920 is pressed on the surface of the pick roller 910
due to the elasticity of the spring 940. Due to different friction
forces among the pick roller 910, the pieces of paper and the
separator pad 920, pieces of paper are conveyed to the office
devices one by one.
[0006] However, in FIG. 3, in operation, when too much paper sheets
950 are inserted into a region A between the separator pad 920 and
the pick roller 910 of the conventional sheet separating mechanism,
the separator pad 920 is raised up due to certain thickness of the
sheets 950 and then drives the press plate 930 (see FIG. 1) to move
upward. So the front of the separator pad 920 is away from the pick
roller 910 to form a region B. And the attrition produced in use
also causes the front of the separator pad 920 to be away from the
pick roller 910. When the front of the separator pad 920 keeps a
region B from the pick roller 910, the too much paper sheets 950
inserted into the region A can all pass through between the
separator pad 920 and the pick roller 910 and then be conveyed to
the office device. In this case, the sheet separating is false,
namely, reliability of sheet separating is much low.
SUMMARY OF THE INVENTION
[0007] Accordingly, an object of the invention is to provide a
sheet separating mechanism of an auto sheet feeder to enhance the
reliability of paper separating.
[0008] To achieve the object, a sheet separating mechanism used for
an auto sheet feeder having a pick roller and an upper frame is
provided. The mechanism includes a bracket and a pair of spring
arms disposed on the bracket and spring-biased toward the pick
roller for maintaining a plurality of sheets on the pick roller
during transportation of the sheets. A separator pad is disposed on
the bracket and spring-biased toward the pick roller for
cooperating with the pick roller to permit further transportation
of a lowermost sheet of the plurality of the sheets. A press plate
is positioned on the bracket and presses against the separator pad.
A torsion spring is mounted above the press plate and has at least
two coil portions spaced and opposite to the adjacent coil portion.
Two adjacent ends of the coil portions extend toward the same side
and then joint each other to form a contact portion which always
props the upper frame. Two ends of the torsion spring have a
retaining arm respectively. The two retaining arms pivotally engage
to two sides of the press plate respectively. The torsion spring is
compressed by the press plate when the sheets push the separator
pad to detach from the pick roller and pushes the press plate and
the separator pad to be reposition after the lowermost one of the
sheets is separated.
[0009] An auto sheet feeder used for a device where separation of a
single sheet from a plurality of sheets is desired, the feeder
comprises an upper frame, a pick roller and a sheet separating
mechanism secured on the upper frame. The sheet separating
mechanism includes a bracket and a pair of spring arms disposed on
the bracket and spring-biased toward the pick roller for
maintaining a plurality of sheets on the pick roller during
transportation of the sheets. A separator pad is disposed on the
bracket and spring-biased toward the pick roller for cooperating
with the pick roller to permit further transportation of a
lowermost sheet of the plurality of the sheets. A press plate is
positioned on the bracket and presses against the separator pad. A
torsion spring is mounted above the press plate and has at least
two coil portions spaced and opposite to the adjacent coil portion.
Two adjacent ends of the coil portions extend toward the same side
and then joint each other to form a contact portion which always
props the upper frame. Two ends of the torsion spring have a
retaining arm respectively. The two retaining arms pivotally engage
to two sides of the press plate respectively. The torsion spring is
compressed by the press plate when the sheets push the separator
pad to detach from the pick roller and pushes the press plate and
the separator pad to be reposition after the lowermost one of the
sheets is separated.
[0010] As described above, because the press plate is pivotally
configured on the retaining arms of the torsion spring and presses
on the separator pad, the press plate can adjust itself constantly
to always press the separator pad close to the pick roller, which
ensures that only one paper sheet can pass through between the
separator pad and the pick roller to be conveyed to the office
device once. Thereby the reliability of paper separating of the
sheet separating mechanism is enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be apparent to those skilled in
the art by reading the following description of a preferred
embodiment thereof, with reference to the attached drawings, in
which:
[0012] FIG. 1 is a perspective view of a conventional sheet
separating mechanism;
[0013] FIG. 2 is a lateral view of the sheet separating mechanism
in FIG. 1;
[0014] FIG. 3 is a lateral view of a state of the paper separating
process of the sheet separating mechanism in FIG. 1;
[0015] FIG. 4 is a perspective view of a sheet separating mechanism
of an auto sheet feeder according to the present invention;
[0016] FIG. 5 is a perspective view of an upper frame of the auto
sheet feeder;
[0017] FIG. 6 is an enlarged view of a part VI in FIG. 5;
[0018] FIG. 7 is an exploded view of the sheet separating mechanism
in FIG. 4;
[0019] FIG. 8 is another perspective view of a bracket and a pick
spring of the sheet separating mechanism in FIG. 7;
[0020] FIG. 9 is a perspective view of a torsion spring of the
sheet separating mechanism in FIG. 7;
[0021] FIG. 10 is a perspective view of a press plate of the sheet
separating mechanism in FIG. 7;
[0022] FIG. 11 is a perspective view of a natural state of the
torsion spring of the sheet separating mechanism in FIG. 7;
[0023] FIG. 12 is a perspective view of a distorted state of the
torsion spring of the sheet separating mechanism in FIG. 7; and
[0024] FIG. 13 is a lateral view of the sheet separating mechanism
in FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] We define the conveying direction of the paper as a front
direction.
[0026] Referring FIG. 4 to FIG. 7, an auto sheet feeder has an
upper frame 200 and a pick roller 100 located under the upper frame
200. A sheet separating mechanism 10 of the auto sheet feeder
includes a bracket 300, a pick spring 400, a press pad 500, a
separator pad 600, a press plate 710 and a torsion spring 740.
[0027] Refer to FIGS. 5 and 6, the upper frame 200 has a press
surface 210 which faces the bracket 300. Two supporting lumps 220
protrude from the press surface 210. Each supporting lump 220
defines a protruding peg 222 protruding toward each other.
[0028] In FIGS. 4, 7 and 8, the bracket 300 is mounted to the upper
frame 200 and disposed above the pick roller 100. The bracket 300
has a support board 310. A plurality of location pegs 311
vertically project upward from the proper places of the support
board 310. Two lateral sides of the support board 310 extend upward
and downward to form a fixing portion 340 respectively which is
fixed on the upper frame 200. The bottom of the support board 310
bents and extends backward to form a prop board 320. The middle
surface of the prop board 320 is dented to form a receiving groove
322. Two sparing grooves 324 are formed on two sides of the
receiving groove 322 for economizing on stuff. The backside of the
prop board 320 is dented to form a fixing groove 326. Two fixing
pegs 328 extend downward from the bottom of the prop board 320.
[0029] The pick spring 400 has a rectangular holding portion 410. A
plurality of location holes 411 are defined in the holder portion
410 for mating with the location pegs 311 to fix the holder portion
410 on the support board 310 of the bracket 300. A spring press
portion 430 extends downward from the bottom of the holding portion
410. The spring press portion 430 includes a press arm 432 to be
received in the receiving groove 322 and a press tip 434 bent
forward from the free end of the press arm 432. Two ends of the top
of the holding portion 410 extend and then bend downward to form
two clipping portions 421. The clipping portions 421 clip the top
rim of the support board 310. The free end of each clipping portion
421 extends and then bends forward to form a spring arm 422 with a
hooked tip pressed on surface of the pick roller 100.
[0030] The press pad 500 includes a pad holder 510 and a pad press
portion 520 bending and extending forward from the bottom of the
pad holder 510. The pad holder 510 is fixed in the fixing groove
326 of the bracket 300. The pad press portion 520 is placed in
front of the spring arms 422. The tip of the pad press portion 520
faces the surface of the pick roller 100. A small gap is formed
between the tip of the pad press portion 520 and the pick roller
100.
[0031] The separator pad 600 is placed in front of the press pad
500. The friction coefficient of the separator pad 600 is larger
than that of the paper sheets and smaller than that of the pick
roller 100. The separator pad 600 has a separator portion 630 of a
block shape. Two fixing holes 632 are defined in the separator
portion 630 for mating with the fixing pegs 328 to fix the
separator pad 600 on the prop board 320 of the bracket 300. A
separator press portion 636 is formed in the separator portion 630.
The press tip 434 of the pick spring 400 presses on the separator
press portion 636 to make the separator press portion 636 protrude
downward to contact the pick roller 100.
[0032] With reference to FIGS. 4, 7 and 10, the press plate 710
includes a plate portion 711 of a block shape and two axial
protruding portions 715 protruding upward from two ends of the
plate portion 711. Each axial protruding portion 715 defines an
axial hole 716 penetrating transversely therethrough. The plate
portion 711 presses on the surface of the separator portion 630 of
the separator pad 600.
[0033] In FIGS. 4, 7 9 and 11, the torsion spring 740 is mounted
transversely above the press plate 710 and has two coil portions
741 spaced and opposite to each other. Each coil portion 741 is
hollow and arranged around the protruding peg 222. Two adjacent
ends of the coil portions 741 extend toward the same side and then
joint each other to form a U-shaped contact portion 742 which
always presses on the press surface 210 of the upper frame 200. Two
ends of the torsion spring 740 define a retaining arm 743 extending
and bending outward respectively. The two retaining arms 743
pivotally engage to two sides of the press plate 710 respectively.
The tip of each retaining arm 743 bends to form a pivot 744. The
two pivots 744 are pivotally inserted into the two axial holes 716
of the press plate 710 respectively.
[0034] When the sheet separating mechanism 10 is assembled, the
coil portions 741 of the torsion spring 740 are distorted. The
retaining arms 743 arranged on the press plate 710 and the contact
portion 742 pressing on the upper frame 200 respectively produce
force F' and force F as showing in FIG. 12.
[0035] With reference to FIGS. 4, 7 and 13, in operation, pieces of
paper placed on the paper feeding tray (not shown) is drawn forward
along with the rotation of the pick roller 100 due to their own
weight. The leading ends of the paper sheets firstly push forward
the spring arms 422 of the pick spring 400 and enter between the
pick roller 100 and the spring arms 422. The spring arms 422 exert
a pressure on the paper, which adds the friction between the
lowermost paper and the pick roller 100. Due to the action of the
spring arms 422, the lowermost paper is conveyed forward with the
rotation of the pick roller 100. The pad holder 510 of the press
pad 500 blocks some pieces of paper from being further conveyed
when pieces of paper arrive at the pad holder 510. The left pieces
of paper are conveyed forward. The pad press portion 520 of the
press pad 500 presses the paper sheets to prevent them from
curling.
[0036] The lowermost paper and the pieces of paper thereon move to
the separator pad 600. As the press tip 434 of the pick spring 400
presses on the separator press portion 636, the separator press
portion 636 of the separator pad 600 approaches the pick roller
100. A few pieces of paper are inserted between the separator press
portion 636 and the pick roller 100 and conveyed to the separator
portion 630 and the pick roller 100. As the retaining arms 743 of
the torsion spring 740 produce the force F showing in FIG. 12 which
make the press plate 710 exert pressure on the separator portion
630 of the separator pad 600, then the separator portion 630 is
near to the pick roller 100. When the paper inserted between the
separator portion 630 and the pick roller 100, the separator
portion 630 is raised upward and further drives the press plate 710
to move upward. The torsion spring 740 will further be distorted.
So the retaining arms 743 pivotally arranged on the press plate 710
exert pressure on the press plate 710 to rotate around the pivots
744 and further press the separator portion 630 of the separator
pad 600 close to the paper inserted between the separator portion
630 and the pick roller 100. As the friction coefficient of the
separator pad 600 is larger than that of the paper but smaller than
that of the pick roller 100, the paper sheets on the lowermost
paper are prevented from entering the position where the separator
portion 630 is in contact, and the lowermost paper only passes
through between the pick roller 100 and the separator portion 630.
After the paper is separated completely, the torsion spring 740 is
released to press the press plate 710 downward, and the press plate
710 rotates around the pivots 744 and further pushes the separator
portion 630 to contact the pick roller 100 again for a next paper
separating.
[0037] According to the sheet separating mechanism 10 of the
present invention as described above, because the retaining arms
743 of the distorted torsion spring 740 produces the force F and
the pivots 744 of the torsion spring 740 are pivotally arranged in
the axial holes 716 of the press plate 710, the press plate 710 can
adjust itself around the pivots 744 to close to the separator pad
600, which ensures the separator pad 600 is always close to the
pick roller 100 or the paper inserted between the separator pad 600
and the pick roller 100 during the process of paper separating.
When too much pieces of paper insert between the separator pad 600
and the pick roller 100, the retaining arms 743 exert pressure on
the press plate 710 to rotate down, which makes the raised
separator pad 600 close to the pick roller 100 to ensure the
friction relation between the separator pad 600, the pick roller
100 and the paper. So when too much paper sheets insert between the
separator pad 600 and the pick roller 100, only the lowermost paper
also can be exactly separated by the sheet separating mechanism 10.
So the reliability of paper separating is enhanced. Otherwise, as
the torsion spring 740 is arranged transversely, which reduces the
lengthways space and furthermore reduces the bulk of the sheet
separating mechanism 10.
[0038] An embodiment of the present invention has been discussed in
detail. However, the embodiment is merely specific examples for
clarifying the technical contents of the present invention and the
present invention is not to be construed in a restricted sense as
limited to the specific examples. Such modifications and variations
that may be apparent to those skilled in the art are intended to be
included within the scope of this invention as defined by the
accompanying claims.
* * * * *