Paperfeed system for optoelectronic scanner

Abstract: A plurality of pinch rollers (17, 21) (18, 22) are employed to drive sheets (11) of paper containing material to be scanned past an optical scanner to generate an optical image of the material which is converted into electrical signals. Each pinch roller (17, 21) (18, 22) includes a drive roller (17, 18) which is driven by a synchronized drive mechanism and an idler roller (21, 22). The support shafts for the idler rollers (21, 22) are supported in elongated bearings (21a, 22a) which provide limited freedom of motion for the idler rollers (21, 22) in a direction substantially normal to their axes of rotation. A pressure plate (29) has spring fingers (51, 52) which resiliently urge the idler rollers (21, 22) towards the drive rollers (17, 18) to resiliently pinch the paper sheets (11) being driven. In the event that the paper (11) should become jammed and needs to be removed or repositioned, a roller release lever (37) can be actuated to drive the pressure plate (29) so as to permit the idler rollers (21, 22) to move freely in their elongated support bearings (21a, 22a). Further, a friction pad (36) is provided which rides on the surface of the paper (11) so that in the event that more than one sheet of paper (11) should pass through the rollers (17, 21) (18, 22) only the lowermost sheet will pass through.

Description: This invention relates to a paper feed system for an opto-electronic scanner and more particularly to such a system which employs pinch rollers for driving the paper. US-A-4667253 discloses an optical line scanner which employs pinch rollers for driving sheets of paper past an optical scanner to be optically scanned. In the event of a paper jam, or other equipment malfunction, it is necessary to release the paper from the rollers in a simple and expeditious manner. This end result is achieved in US-A-4667253 by mounting the idler rollers on a floating bracket which is resiliently urged towards the drive rollers. A release lever is provided to cause the floating bracket to be driven so as to release the idler rollers from the drive rollers. Japanese Patent No. JP-A-59/178273 discloses a paper feeding system which comprises two separate pressure rollers (idler rollers) contacting a platen by rotating a shaft. Such paper feeding system performs similarly to the traditional typewriter paper feed system, in which the paper sheets can only be fed one by one manually. Another similar type of paper removal/feeding system, disclosed in Japanese Patent No. JP-A-59/167432, comprises two sets of idler and driver rollers, and is focused on how to remove easily the jammed paper. Paper can be driven between the idler rollers and drive rollers. By moving the drive rollers downwardly, the upper idler rollers will at the same time move up such that more space can be left between the two sets of rollers for the removal of jammed paper from the plate. The prior patent can not perform the function of gradually separating multiple paper sheets from a scanner. In contrast, the present invention further comprises an automatic paper-separating mechanism so that the scanner can automatically separate paper sheets and make the task of feeding them less laborious. The system of the present invention is intended to provide an improved mechanism for achieving this end result and to be of simpler more compact construction. Further the system of the present invention is to be capable of operating with a single lever a plurality of idler rollers which are spaced over a fairly large distance. In addition, the system of the present invention provides means for separating two sheets from each other, permitting only a single sheet to be fed through the rollers, this in the event that more than one sheet is inadvertently carried into the rollers. The present invention is defined by claim 1. The preamble of claim 1 is based on the disclosure of JP-A-59/167432. Further a tension pad of friction material may be provided which abuts against the upper face of the paper being fed through the rollers. Thus, if there is more than one sheet in the feed system, the upper sheet will be held by the pad while the lowermost sheet will be permitted to pass through, avoiding the feeding of more than one sheet at a time. In order that this invention may more readily become apparent, the following description is given merely by way of example, taken in connection with the accompanying drawings, in which: FIG 1 is a perspective view of a preferred embodiment of the invention; FIG 2 is a cross-sectional view taken along the line 2-2 of FIG 1, showing the preferred embodiment in its normal operating condition. FIG 3 is a cross-sectional view showing the preferred embodiment with the paper release lever in the "release" position; and FIG 4 is a front elevational view taken along the plane indicated by 4-4 in FIG 2 of the pressure plate employed in the device of the invention. Referring now to Figs 1, 2 and 4, the preferred embodiment is shown in its normally operating condition. The paper 11 to be scanned is fed past the scanner, which includes a lamp 14, by means of pinch rollers formed by drive rollers 16, 17, and 18 which operate in conjunction with idler rollers 20, 21 and 22 respectively. The support shafts for idler rollers 21 and 22 are mounted in elongated bearings 21a and 22a respectively so that these rollers have limited freedom of motion along axes normal to their rotation axes. Pressure plate 29 has a pair of spring fingers 51 and 52 which abut against the idler roller drive shafts and resiliently urge these rollers towards their associated drive rollers such that the paper is pinched between the paired rollers. Pressure plate 29 is pivotally supported on the shaft 50 which in turn is mounted on the support frame 56. The top end of tension plate 29 is urged upwardly by means of springs 60 so that the portion thereof on the opposite side of pivot support shaft 50 which includes spring fingers 51 and 52 is urged against the idler roller shafts. The paper inlet pinch roller, which is formed by drive roller 16 and idler roller 20, has a separate spring for urging the idler towards the drive roller and can be separately lifted manually in the manner of a conventional typewriter roller. The scanner may be of the type described in US-A-4,667,253. The drive rollers are driven by means of a motor (not shown) operating in conjunction with a series of drive belts 25 and 26 and others (not shown). The entire assembly is mounted within a housing 30 which can readily be disassembled to enable repair of the equipment. Pressure pad 35 is fixedly attached to flat plate 36 which in turn is pivotally supported on pressure plate 29 by means of hinge pin 38. Pad 35 rests on the paper 11 by virtue of gravity, but may additionally be urged against the paper by means of a spring. The pad is fabricated of a suitable friction material such as rubber, and is positioned at an angle to the uppermost of a stack of sheets 11 so as to impede its advance. The bottom sheet, being in contact with the driver roller 62, which by design has higher friction than the friction pad 35, is pushed past pad 35 and further transported through the scanner by the rollers 17 and 18 and their associated idlers 21 15 and 22 respectively. Referring now to Fig 3, the device is shown with the release lever actuated to release the idler rollers from the drive rollers and thus free the paper. Release lever 37 normally forms part of the top wall of housing 30 and is pivotally supported on support pin 41. When lever 37 is positioned as shown in Fig 3, the end 37a thereof abuts against pressure plate 29 and drives this plate away from the idler wheels 21 and 22 leaving these wheels free from their associated drive wheels 17 and 18, the idler wheels being free to ride upwardly in their associated elongated bearings. In this manner the pinch rollers release their hold on the paper 11 so that it can either be withdrawn or adjusted in position as may be desired. The system of the invention thus provides a paper feeder for a device such an opto-electronic scanner having a paper release mechanism which operates to release widely separated pinch rollers with a single actuation of a lever. In addition, a sample yet highly effective mechanism is provided for separating multiple sheets from each other in the event that they should be inadvertently fed into the feed system at the same time.

Claims: A paper feed system for feeding sheets of paper along a predetermined path, said system including a plurality of pinch rollers (17, 21)(18,22) formed by pairs of drive rollers (17,18) and idler rollers (21, 22), each of said idler rollers (21, 22) being rotatably supported on a support shaft, means for resiliently urging said idler rollers (21, 22) towards said drive rollers (17, 18) to drive a sheet of paper (11) therebetween; and means for releasing the idler rollers from said resilient urging comprising: a pressure plate (29), means for resiliently urging said pressure plate against each of said idler rollers, and a release lever (37) having a first position in which it does not drive said pressure plate (29) and a second position in which it drives against said pressure plate to drive said plate out of engagement with said idler rollers (21, 22) thereby permitting said idler rollers to move away from their associated drive rollers (17, 18); characterized by elongated bearing means (21a, 22a) for supporting each of said idler rollers (21, 22) for limited freedom of motion along an axis normal to the rotation axis thereof; by the fact that the pressure plate comprises spring means (51, 52) abutting against each of said idler roller support shafts; and by means (60) for resiliently urging said pressure plate to cause said spring means to urge each of said idler rollers against its associated drive roller. A system according to claim 1, characterised in that there are two pairs of idler and drive rollers (17, 21)(18,22) which are separated from each other; and in that said pressure plate spring means (51, 52) comprise a pair of spring fingers which abut against the shafts of said idler rollers. A system according to claim 1 or 2, characterised in that said release lever (37) is pivotally mounted and is adapted to be manually actuated to the release position whereat it abuts against the pressure plate (29) to drive it out of engagement with the idler rollers (21, 22). A system according to claim 1, 2 or 3, further characterised by pressure pad means (35, 36, 38) which abuts against the top surface of the paper (11) as it is being fed between said rollers (17, 21)(18, 22) for providing friction against the top paper surface to permit the bottom sheet of paper to move through the rollers first. A system according to claim 4, characterised in that said pressure pad means (35) comprises a plate (36), means (38) for pivotally supporting said plate, and a pad (35) of resilient material affixed to said plate and abutting against the top paper surface by virtue of the force of gravity. A system according to any one of claims 1 to 5, further characterised by pivotal support means (50) for pivotally supporting said pressure plate, said means for resiliently urging said pressure plate comprising springs (60) which abut against said pressure plate (29) and urge said pressure plate pivotally about said support means (50).

Inventors: CHEN PHILIP L, CHEN, PHILIP L.
Applicants: MICROTEK LAB INC, MICROTEK LAB, INC.
Application year: 1989
Main classification: B41J13
IPC codes: H04N1, B65H5