US20080054549A1

US20080054549A1 - Document feeder

Info

Publication number: US20080054549A1
Application number: US11/470,448
Authority: US
Inventors: Hsin-Wen Lee
Original assignee: Primax Electronics Ltd
Current assignee: Primax Electronics Ltd
Priority date: 2006-07-17
Filing date: 2006-09-06
Publication date: 2008-03-06
Also published as: TW200806482A; JP2008024505A; JP4505444B2; TWI290098B

Abstract

A document feeder includes a housing, a sheet pick-up arm and a stopper. The housing includes a sheet feeding path for placing paper sheets thereon. The sheet pick-up arm is movable between a first position and a second position. The sheet pick-up arm has a protrusion structure. The stopper is disposed under the sheet feeding path and includes a pivotal portion and a sheet stop portion. The sheet stop portion has a hooking part corresponding to the protrusion structure. When the sheet pick-up arm is moved to the first position, the protrusion structure is located in the swing track of the hooking part to restrain the swing range of the sheet stop portion. When the sheet pick-up arm is moved to the second position, the protrusion structure is deviated from the swing track of the hooking part to permit free swing of the sheet stop portion.

Description

FIELD OF THE INVENTION

The present invention relates to a document feeder, and more particularly to a document feeder having a stopper.

BACKGROUND OF THE INVENTION

Conventionally, for scanning several paper sheets, the paper sheets should be manually placed on the scanning platform of the image scanners one by one. This means of manually feeding the paper sheets is time-consuming and laboring. Nowadays, the image scanner usually has a document feeder for successively and continuously feeding many paper sheets. As known, a conventional document feeder has a sheet pick-up module arranged in the sheet feeding path for automatically feeding the paper sheets one by one at a time.
For assuring that a stack of paper sheets are precisely positioned within the sheet feeding path, the document feeder further has a stopper under the sheet pick-up module. When the stack of paper sheets enters the sheet feeding path, the stopper is sustained against the front edges of the stack such that the paper sheets are positioned under the sheet pick-up module. Once the paper sheets are stopped by the stopper, the user may feel that the paper sheets are placed in position. When the sheet pick-up module performs the sheet pick-up operation, the stopper is shifted such that the paper sheets are smoothly transported through the sheet feeding path.
Please refer to FIG. 1, which is a schematic perspective view illustrating relative locations of the sheet pick-up module and the stopper of a conventional document feeder. The stopper 12 is pivotal and disposed under the sheet pick-up module 11. The sheet pick-up module 11 comprises a sustaining portion 111. Correspondingly, the stopper 12 comprises a tilt portion 121 and a sheet stop portion 122. When the sheet pick-up module 11 is lifted to a standby position, the sheet stop portion 122 is rotated to an upright position so as to be sustained against the front edges of the stack of paper sheets. Whereas, during the sheet pick-up module 11 is lowered to a sheet pick-up position, the sustaining portion 111 is also lowered down to touch the tilt portion 121 of the stopper 12. In response to the external force generated from rotation of the sheet pick-up module 11, the sheet stop portion 122 is rotated under the sheet feeding path. Under this circumstance, the paper sheets can be smoothly transported through the sheet feeding path without being stopped by the stopper 12.
However, the stopper 12 of the conventional document feeder still has some drawbacks. For example, when the sheet pick-up module 11 is in the standby position, the sheet stop portion 122 of the stopper 12 is only sustained against the lower portions of the paper sheets, but the upper portion of the paper sheets may suppress the tilt portion 121 of the stopper 12. As a result, the sheet stop portion 122 is rotated under the sheet feeding path before the sheet pick-up operation is done, so that the function of the stopping the paper sheets is lost.
In views of the above-described disadvantages resulted from the prior art, the applicant keeps on carving unflaggingly to develop an improved document feeder according to the present invention through wholehearted experience and research.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a document feeder for properly stopping or allowing the paper sheets to be transported through the sheet feeding path with the cooperation of the sheet pick-up arm and the stopper.
In accordance with an aspect of the present invention, there is provided a document feeder. The document feeder includes a housing, a sheet pick-up arm and a stopper. The housing includes a sheet feeding path for placing paper sheets thereon. The sheet pick-up arm is pivotally mounted above the sheet feeding path and movable between a first position and a second position. The sheet pick-up arm has a protrusion structure. The stopper is disposed under the sheet feeding path and includes a pivotal portion and a sheet stop portion. The sheet stop portion has a hooking part corresponding to the protrusion structure. When the sheet pick-up arm is moved to the first position, the protrusion structure is located in the swing track of the hooking part to restrain the swing range of the sheet stop portion. When the sheet pick-up arm is moved to the second position, the protrusion structure is deviated from the swing track of the hooking part to permit free swing of the sheet stop portion.
In an embodiment, the sheet pick-up arm comprises a sheet pick-up roller and a sheet separation roller.
In an embodiment, the document feeder further comprises a driving shaft for driving the sheet pick-up arm, wherein the sheet separation roller is sheathed around the driving shaft.
In an embodiment, the stopper further comprises a loading portion. The loading portion and the sheet stop portion are arranged on opposite sides of the pivotal portion. With the pivotal portion serving as a fulcrum, the torque applied on the loading portion is greater than the torque applied on the sheet stop portion.
In an embodiment, the document feeder further comprises a torsion spring having an end sustained against the sheet stop portion.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating relative locations of the sheet pick-up module and the stopper of a conventional document feeder;

FIG. 2 is a schematic perspective view of a document feeder according to a preferred embodiment of the present invention;

FIG. 3A is a schematic perspective view illustrating relative locations of the sheet pick-up module and the stopper when the sheet pick-up module is adjusted to a standby position;

FIG. 3B is a schematic perspective view illustrating relative locations of the sheet pick-up module and the stopper when the sheet pick-up module is adjusted to a sheet feeding position;

FIGS. 4A-4F are schematic cross-sectional views illustrating the process of performing the sheet pick-up operation by the sheet pick-up module and the stopper of the present document feeder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 2, a schematic perspective view of a document feeder according to a preferred embodiment of the present invention is illustrated. The document feeder 2 includes a housing 20, a sheet pick-up module 21 and a stopper 22. The housing 20 has a sheet feeding path 201 for placing therein the paper sheets S to be transported therethrough. The sheet pick-up module 21 is pivotally mounted above the sheet feeding path 201 for feeding the paper sheets S through the sheet feeding path 201. The sheet pick-up module 21 includes a sheet pick-up arm 211 and a driving shaft 212. The sheet pick-up arm 211 includes a sheet pick-up roller 211A and a sheet separation roller 211B (as is shown in FIG. 3A). The sheet separation roller 211B is also sheathed around the driving shaft 212. After the sheet pick-up operation has been done, the sheet pick-up arm 211 is lifted to a standby position upon rotation of the driving shaft 212. For a purpose of feeding the paper sheets, the driving shaft 212 is driven to rotate in the opposite direction such that the sheet pick-up arm 211 is lowered to the sheet feeding position. Meanwhile, a sheet pick-up roller 221A of the sheet pick-up arm 212 transports the paper sheets S forwardly and the sheet separation roller 211B of the sheet pick-up arm 212 is rotated to separate the top paper sheets from the stack of paper sheets, thereby picking a single paper sheets.
Please refer to FIG. 2 again. The document feeder 2 further includes a stopper 22 accommodated within a recess 202 under the sheet feeding path 201, as is also shown in FIG. 4A. When the sheet pick-up arm 211 of the sheet pick-up module 21 is lifted to the standby position, the stopper 22 is rotated to an upright position so as to be sustained against the front edges of the stack of paper sheets. As a result, the stack of paper sheets S fails to be transported through the sheet feeding path 201. Whereas, during the sheet pick-up module 21 is lowered to a sheet pick-up position, a free swing of the stopper 22 is rendered. Under this circumstance, the stack of paper sheets S may suppress the stopper 22 and is then transported through the sheet feeding path 201.
Please refer to FIGS. 3A and 3B, which are schematic perspective views illustrating relative locations of the sheet pick-up module 21 and the stopper 22 when the sheet pick-up module 21 is adjusted to a standby position and a sheet feeding position, respectively. As can be seen in FIGS. 3A and 3B, the stopper 22 is made upright when the sheet pick-up arm 211 of the sheet pick-up module 21 is lifted to the standby position, and a free swing of the stopper 22 is rendered when the sheet pick-up arm 211 of the sheet pick-up module 21 is lowered to the sheet feeding position.
The stopper 22 includes a pivotal portion 221, a loading portion 222 and a sheet stop portion 223. The pivotal portion 221 is accommodated within a recess 202 (as is also shown in FIG. 4A). The pivotal portion 221 is substantially a cylindrical post serving as a rotating shaft of the stopper 22. That is, by using the pivotal portion 221 as the fulcrum, the loading portion 222 and the sheet stop portion 223 are rotatable. The sheet stop portion 223 is substantially a stop plate to be sustained against the front edges of the stack of paper sheets S. The loading portion 222 and the sheet stop portion 223 are arranged on opposite sides of the pivotal portion 221. With the pivotal portion 221 serving as the fulcrum, the torque applied on the loading portion 222 is greater than the torque applied on the sheet stop portion 223. As a consequence, once the sheet stop portion 223 is not suppressed by the paper sheets S, the sheet stop portion 223 will be returned toward the upright position due to the torque applied on the loading portion 222.
In addition, the sheet stop portion 223 has a hooking part 223A extending from a first lateral side thereof. Corresponding to the hooking part 223A, the sheet pick-up arm 211 has a protrusion structure 211C extending from a second lateral side thereof. When the sheet pick-up arm 211 is lifted to the standby position as shown in FIG. 3A, the hooking part 223A of the sheet stop portion 23 is located in the swing track 223A′ of the hooking part 223A, thereby restraining the swing range of the sheet stop portion 223. That is, when the sheet pick-up arm 211 is lifted to the standby position, the hooking part 223A of the sheet stop portion 23 is hooked onto the protrusion structure 211C of the sheet pick-up arm 211 such that the sheet stop portion 223 maintains upright to stop the paper sheets. When the sheet pick-up arm 211 is lowered to the sheet feeding position as shown in FIG. 3B, the hooking part 223A of the sheet stop portion 23 is deviated from the swing track 223A′ of the hooking part 223A to permit free swing of the sheet stop portion 23.
In this embodiment of the document feeder 2, the hooking part 223A is extended from the first lateral side of the sheet stop portion 223, and the protrusion structure 21 IC is extended from the second lateral side of the sheet pick-up arm 211. When the hooking part 223A is located in the swing track 223A′ of the hooking part 223A, the sheet stop portion 223 will maintains at its upright position to stop the paper sheets. Whereas, the hooking part 223A is deviated from the swing track 223A′ of the hooking part 223A, a free swing of the sheet stop portion 23 is permitted such that the paper sheets S is transported through the sheet feeding path 201.
As previously described, in the conventional document feeder, the upper portions of the paper sheets may suppress the tilt portion of the stopper when the sheet pick-up module is in the standby position. That is, the function of the stopping the paper sheets is readily lost by using the conventional document feeder. By the present document feeder 2, with the cooperation of the hooking part 223A of the sheet stop portion 23 and the protrusion structure 211C of the sheet pick-up arm 211, the function of stopping the paper sheets is selectively enabled or disabled when the sheet pick-up arm 211 is lifted to the standby position or lower to the sheet feeding position. As a consequence, the upper portions of the paper sheets are still stopped when the paper sheets S are placed on the sheet feeding path.
Hereinafter, a process of performing the sheet pick-up operation by the sheet pick-up module 21 and the stopper 22 of the document feeder 2 will be illustrated with reference to FIGS. 4A-4F.
First of all, as shown in FIG. 4A, when the sheet pick-up arm 211 is lifted to the standby position, the hooking part 223A of the sheet stop portion 23 is hooked onto the protrusion structure 21 IC of the sheet pick-up arm 211. Under this circumstance, the sheet stop portion 223 of the stopper 22 is made upright and thus the paper sheets S are hindered from being transported through the sheet feeding path 201. Moreover, since the hooking part 223A is hooked onto the protrusion structure 21 IC, the stopper 22 will not be suppressed by the sheet pick-up arm 211 to rotate.
Next, as shown in FIG. 4B, the sheet pick-up arm 211 is lowered to the sheet feeding position, and the sheet pick-up roller 21 1A is rotated on the top paper sheets. As the sheet pick-up arm 211 is lowered to the sheet feeding position, the protrusion structure 211C is detached from the hooking part 223A and thus a free swing of the sheet stop portion 223 of the stopper 22 is rendered.
Next, as shown in FIG. 4C, upon rotation of the sheet pick-up roller 21 1A, the top paper sheets S is transported to enter the sheet feeding path 201. During the process of transporting the top paper sheets S into the sheet feeding path 201, the sheet stop portion 223 of the stopper 22 is swung toward the sheet feeding path 201 by the paper sheets S.
In FIG. 4D, as the sheet pick-up roller 21 1A of the sheet pick-up arm 211 is continuously rotated, the sheet stop portion 223 of the stopper 22 is suppressed by the paper sheets S to be fully accommodated within the recess 202.
In FIG. 4E, after the paper sheets S is transported across the sheet stop portion 223, the sheet stop portion 223 of the stopper 22 is no loner suppressed by the paper sheets S. Meanwhile, the sheet stop portion 223 will be returned toward the upright position due to the torque applied on the loading portion 222.
After the sheet feeding operation is finished, the sheet pick-up arm 211 is lifted to the standby position. Meanwhile, the protrusion structure 21 IC is located in the swing track 223A′ of the hooking part 223A, thereby restraining the swing range of the sheet stop portion 223.
Please refer to FIG. 3A, 4D and 4E. The sheet pick-up arm 211 of the document feeder 2 further comprises a stopping piece 211D corresponding to the sheet stop portion 223. After the paper sheets S is transported across the sheet stop portion 223 and the sheet stop portion 223 is swung backwardly, the end of the sheet stop portion 223 is stopped by the stopping piece 211D such that the sheet stop portion 223 is in the upright position.
As previously described, the sheet stop portion 223 will be kept at the upright position due to the torque applied on the loading portion 222. Alternatively, the document feeder 2 further includes a torsion spring 224 having an end sustained against the sheet stop portion 223. Once the paper sheets S suppresses the sheet stop portion 223 to permit rotation of the sheet stop portion 223, a torsion force is resulted from the torsion spring 224. After the paper sheets S is transported across the sheet stop portion 223 and the sheet stop portion 223 is no longer suppressed by the sheet stop portion 223, the torsion force of the torsion spring 224 will facilitate the reverse rotation of the sheet stop portion 223 to the upright position.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

1. A document feeder comprising:

a housing including a sheet feeding path for placing paper sheets thereon;

a sheet pick-up arm pivotally mounted above said sheet feeding path and movable between a first position and a second position, wherein said sheet pick-up arm has a protrusion structure; and

a stopper disposed under said sheet feeding path and comprising a pivotal portion and a sheet stop portion, said sheet stop portion having a hooking part corresponding to said protrusion structure,

wherein said protrusion structure is located in the swing track of said hooking part to restrain the swing range of said sheet stop portion when said sheet pick-up arm is moved to said first position, and said protrusion structure is deviated from the swing track of said hooking part to permit free swing of said sheet stop portion when said sheet pick-up arm is moved to said second position.

2. The document feeder according to claim 1 where said sheet pick-up arm comprises a sheet pick-up roller and a sheet separation roller.

3. The document feeder according to claim 1 further comprising a driving shaft for driving said sheet pick-up arm, wherein said sheet separation roller is sheathed around the driving shaft.

4. The document feeder according to claim 1 wherein said stopper further comprises a loading portion, said loading portion and said sheet stop portion being arranged on opposite sides of said pivotal portion, wherein the torque applied on said loading portion is greater than the torque applied on said sheet stop portion with said pivotal portion serving as a fulcrum.

5. The document feeder according to claim 1 further comprising a torsion spring having an end sustained against said sheet stop portion.