Electrophotography – Document handling – Copy
Reexamination Certificate
2000-08-03
2001-12-11
Chen, Sophia S. (Department: 2852)
Electrophotography
Document handling
Copy
C271S145000, C399S045000
Reexamination Certificate
active
06330423
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus.
Many image forming apparatuses such as electronic copying machines have a manual paper feeder in addition to an automatic cassette paper feeder. Commonly, this manual paper feeder is used to temporarily feed to the main body a paper sheet of a type outside the specification of an automatic paper feed tray. The basic position of such a manual paper feeder remains unchanged at present.
Recently, however, demands on manual paper feeders are more and more increasing. That is, manual paper feeders are required not only to correspond to various types of paper sheets (particularly basis weights) but also to continuously feed a plurality of paper sheets like automatic paper feeders.
These requirements have been conventionally met by adjusting the position, material, shape, and pressing force of each of a paper pickup roller for picking up a paper sheet, a paper feed roller for feeding the picked-up sheet to the main body, and a brake pad for stopping the sheet, as the basic components of a manual paper feeder, or by adjusting the position, angle, guide angle, and the like of a paper stack tray.
Unfortunately, the adjustment of these components such as the paper pickup roller, paper feed roller, brake pad, and paper stack tray cannot unlimitedly cope with diverse types of paper sheets.
Major problems are as follows.
(1) To reliably separate and feed paper sheets having a high friction coefficient between them, a pre-separation function such as an inclined separation guide must be placed before a separation mechanism. However, when the paper feed properties of thick paper sheets are taken into consideration, the guide shape of a paper conveyor for conveying paper sheets must be infinitely approached to a straight line. This contradiction makes it difficult to obtain an appropriate angle meeting the two requirements.
(2) When a condition such as a thickness changes, the friction coefficient and the paper feed property change. Hence, it is difficult to accurately separate and feed such a plurality of types of paper sheets.
In some conventional apparatuses, a manual paper feeder has a tray with an elevating function which can move up and down in accordance with the number or basis weight of paper sheets, like an automatic cassette paper feeder. This system can always maintain the posture of a paper sheet in a stable state regardless of changes in the number or basis weight of paper sheets.
The mechanism, however, of this manual paper feeder becomes complicated and increases in size like an automatic paper feeder. This is a disadvantage in seeking the space utility of an apparatus as a whole.
The present invention has been made in consideration of the above situation, and has as its object to provide an image forming apparatus capable of reliably separating and feeding different types of paper sheets to the main body, with a simple mechanism which can be made small.
SUMMARY OF THE INVENTION
An image forming apparatus of the present invention comprises a paper feed tray, wherein a supporting point position and angle of the paper feed tray change in accordance with an external input.
The paper feed tray can be a manual paper feed tray.
The external input can be given when an operator performs a predetermined input operation on an operation panel.
Alternatively, the external input can be manually given by an operator.
An image forming apparatus of the present invention comprises a paper feed tray on which a paper sheet to be manually fed is placed, wherein a mounting position of the manual paper feed tray with respect to an apparatus main body is adjusted in accordance with the type of paper sheet placed on the paper feed tray.
The apparatus can also be constructed such that the manual paper feed tray comprises a tray for stacking paper sheets, a pair of supporting point members formed at two ends of a leading end portion in a conveyance direction of the tray, a gear being formed in at least a partial circumferential region centering around a first rotation supporting point, a support shaft formed along the first rotation supporting point and having a pair of projections protruding from the supporting point members toward two ends, a pair of rack guides fixed to a main body and having racks which mesh with the gears of the supporting point members and long holes elongated in one direction into which the projections are inserted, a pair of lever gears which rotate around a second rotation supporting point while engaging, with play, with the projections inserted into the long holes and protruding toward two ends, and a driving source for rotating the lever gears, and that when the external input is given, the driving source rotates the lever gears around the second rotation supporting point, the lever gears drive the projections engaged around the second rotation supporting point, the projections slidably move along the long holes in the rack guides fixed to the main body, and the position of the first rotation supporting point moves while the supporting point members rotate around the first rotation supporting point, thereby changing the supporting point position and angle of the manual paper feed tray.
The driving source can comprise a motor.
The supporting point members can have fan-shaped holes centering around the first rotation supporting point, the tray can have fan-shaped projections to be inserted with play into the fan-shaped holes around the first rotation supporting point, and the tray can be accommodated in the main body of the image forming apparatus when the fan-shaped projections pivot in the fan-shaped holes.
The above image forming apparatuses can cope with a variety of types of paper sheets by changing the supporting point position and angle of the paper feed tray by an external input in accordance with the type of paper sheet.
Also, when a conventional elevating function is given to a manual paper feed tray, the mechanism becomes complicated and increases in size. The present invention, however, uses a simple arrangement by which a manual paper feed tray itself changes its supporting point position and angle. Consequently, a paper sheet can be fed in optimum conditions corresponding to the type of paper sheet.
REFERENCES:
patent: 5454555 (1995-10-01), Kiyohara et al.
patent: 05-017037 (1993-01-01), None
patent: 05-092846 (1993-04-01), None
patent: 6-305595 (1994-11-01), None
patent: 07-109052 (1995-04-01), None
patent: 08-104449 (1996-04-01), None
patent: 08-113379 (1996-05-01), None
Chen Sophia S.
Foley & Lardner
Toshiba Tec Kabushiki Kaisha
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