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  Document feederUSPTO Application #: 20080054549Title: Document feeder 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. (end of abstract)
Agent: Kirton And Mcconkie - Salt Lake City, UT, US Inventor: Hsin-Wen Lee USPTO Applicaton #: 20080054549 - Class: 271117 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20080054549. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001]The present invention relates to a document feeder, and more particularly to a document feeder having a stopper. BACKGROUND OF THE INVENTION [0002]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. [0003]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. [0004]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. [0005]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. [0006]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 [0007]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. [0008]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. [0009]In an embodiment, the sheet pick-up arm comprises a sheet pick-up roller and a sheet separation roller. [0010]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. [0011]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. [0012]In an embodiment, the document feeder further comprises a torsion spring having an end sustained against the sheet stop portion. [0013]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 [0014]FIG. 1 is a schematic perspective view illustrating relative locations of the sheet pick-up module and the stopper of a conventional document feeder; [0015]FIG. 2 is a schematic perspective view of a document feeder according to a preferred embodiment of the present invention; [0016]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; [0017]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; [0018]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 [0019]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. Continue reading... Full patent description for Document feeder Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Document feeder patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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