Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
2000-01-24
2001-08-14
Bollinger, David H. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S124000, C271S167000
Reexamination Certificate
active
06273416
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to sheet feeding units and methods, and image readers, and more particularly to an automatic document feeder (“ADF”) which sequentially feeds every one sheet from a pile of sheets, and an automatic sheet feeding method. The sheet feeding device and method according to the present invention are suitable for an ADF in an image reader, such as an image scanner, a copier, and a facsimile machine. Of course, the sheet is not limited to paper, but includes an OHP film and any other sheet material.
A document feeder for use with an image reader may be classified into a manual document feeder (“MDF”) that requires a user to place every sheet to be read on a predetermined table, and an ADF that automatically feeds one by one each sheet when a user places one or more sheets to be read on a predetermined table. Unlike the MDF that requires a user to separate each sheet to be read, the ADF should be equipped with separator/feeder means for separating one sheet from a plurality of sheets to be read and for supplying it to the reading part.
A conventional ADF typically includes, as shown in
FIG. 18
, draw roller
2
, separation roller
4
, separation pad
6
arranged opposite to the separation roller
4
, and tray part
8
opposite to the draw roller
2
. Hereupon,
FIG. 18
is a sectional view of essential part in the conventional document feeder
1
. Plural sheets P are piled up on the tray part
8
. The draw roller
2
is rotatable in an arrow direction and movable up and down as illustrated. The draw roller
2
contacts the uppermost sheet P in the pile and feeds one or more top sheets P between the separation roller
4
and the separation pad
6
. The separation roller
4
rotates in an arrow direction as illustrated, separates one sheet P, in cooperation with the separation pad
6
, and feeds it to the subsequent stage unit.
However, the conventional ADF has several drawbacks. First, left ends of the piled sheets P on the tray part
8
, which arc out of alignment as shown in
FIG. 18
, often cause more than one sheets P to be fed at the same time. Due to the arrangement in which a position of the draw roller
2
is movable up and down according to the number of sheets P on the tray part
8
whereas positions of the separation roller
4
and the separation pad
6
are fixed, a height of the top sheet P in the pile to be introduced to the separation roller
4
differs according to the number of piled sheets P, thereby changing unstably the sheet separation condition according to the height of the sheets P on the tray part
8
. In other words, the conventional ADF has a disadvantage in easily causing the double feed and/or jam due to the insufficient separation of sheets P.
BRIEF SUMMARY OF THE INVENTION
Therefore, it is an exemplified general object of the present invention to provide a novel and useful sheet feeding device and method, and image reader in which the above disadvantages are eliminated.
Another exemplified and more specific object of the present invention is to provide a sheet feeding device and method, and image reader that serve to separate a sheet successfully.
In order to achieve the above objects, a sheet feeder comprises a draw roller movably provided so that the draw roller may contact an uppermost sheet in plural sheets, and feeding one sheet or more including the uppermost sheet, and a separation gate provided downstream relative to the draw roller in a sheet feed direction, and movable according to a movement of the draw roller, the separation gate restricting the number of sheets fed by the draw roller. This sheet feeder thus moves the separation gate according to the movement of the draw roller.
A sheet feeder of another aspect of the present invention comprises a draw roller movably provided so that the draw roller may contact an uppermost sheet in a pile of sheets, and feeding one sheet or more including the uppermost sheet, and a separation gate provided downstream relative to the draw roller in a sheet feed direction, and aligning an edge of the pile with a direction approximately perpendicular to the sheet feed direction. The separation gate in this sheet feeder aligns the ends of the piled sheets with a direction approximately perpendicular to the feed direction.
A sheet feeder of still another aspect of the present invention comprises a draw roller provided movably up-and-down so that the draw roller may contact an uppermost sheet in plural sheets, and feeding one sheet or more including the uppermost sheet, a separation roller which separates the uppermost sheet from those fed by the draw roller and feeds the uppermost sheet, a separation pad which cooperates with the separation roller, and a guide part which contacts the sheet fed by the separation roller, and maintains an approach angle of the sheet to the separation roller. The guide part in this sheet feeder maintains sheet's approach angle to the separation roller and prevents a change of the sheet separation condition.
A sheet feeder of another aspect of the present invention comprises a draw roller provided movably up-and-down so that the draw roller may contact an uppermost sheet in plural sheets, and feeding one sheet or more including the uppermost sheet, a separation roller which separates the uppermost sheet from those fed by the draw roller, and feeds the uppermost sheet, a separation pad which cooperates with the separation roller, and a separation gate provided between the draw roller and the separation roller, and restriction the number of sheets fed by the draw roller feeds to the separation roller. This sheet feeder may realize a two-stage sheet separation using the separation gate and the separation roller (together with the separation pad).
A sheet feeding method of another aspect of the present invention comprises the steps of sequentially feeding one or more sheets from a top of piled sheets placed on a table using a draw roller, restricting using a separating gate, the number of sheets to be fed, adjusting a relative configuration between the separation gate and the draw roller, and separating using a separation pad and a separation roller, a sheet out of those fed through the separation gate. This sheet feeding method thus adjusts the relative configuration between the separation gate and the draw roller.
An image reader of another aspect of the present invention comprises one of the above sheet feeders, and a reading part that reads out a sheet fed by the sheet feeder. This image reader may effect the same operation of the above sheet feeders.
Other objects and further features of the present invention will become readily apparent from the following description of the embodiments with reference to accompanying drawings.
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Amagai Tamio
Watanabe Hirotake
Armstrong Westerman Hattori McLeland & Naughton LLP
Bollinger David H.
Fujitsu Limited
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