Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1998-08-25
2002-01-08
Grant, II, Jerome (Department: 2624)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C271S160000, C399S213000
Reexamination Certificate
active
06337751
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a sheet feeding apparatus for feeding sheets separately one by one and an image processing apparatus using this.
2. Description of Related Art
Conventional image forming apparatus, such as laser printers, and conventional image processing apparatus, such as document scanners, have a structure in which plural sheets are set in a paper tray and separately fed one by one. Such a typical feeding apparatus is shown in FIG.
17
.
Sheets S are set in a tray member
50
, and a pickup roller
52
and a cam
53
coaxial with the pickup roller
52
, which constitute a feeding rotary body, start rotating in a direction of arrow M upon drive of a roller shaft
51
. An intermediate plate
54
is normally urged toward a direction of arrow N by a feeding spring (compression spring)
55
, and a projection
54
a
of the intermediate plate
54
is in contact with the cam
53
. The intermediate plate
54
is rotatable around a shaft
54
b
as a center; when the pickup roller
52
rotates in the direction of arrow M, the projection
54
a
of the intermediate plate
54
is disengaged from the cam
53
, thereby pushing the intermediate plate
54
upward in the direction of arrow N by a feeding spring
55
. This operation makes the topmost sheet of the sheet bundle in contact with the surface of the pickup roller
52
to feed the sheet in a direction of arrow P.
When sheets S are doubly fed at a time of pickup, the sheets are separated by a separation pad
56
. The separation pad
56
is normally urged in a direction of arrow Q by a separation spring (compression spring)
57
, thereby contacting to the pickup roller
52
always with a constant pressure. The sheet S is subsequently fed to the image processing unit
60
by way of a guide passage
59
by a feeding roller pair
58
, thereby subject to a prescribed image processing.
With such a feeding apparatus thus described, however, a rotation axis (shaft
54
b
) of the intermediate plate
54
is located away from the pickup roller
52
to some extent, so that a position of the rotation axis determines the size of the apparatus.
To make such an apparatus compact, in a devised sheet feeding apparatus, the intermediate plate
54
is made smaller in the lengthwise direction, and the sheet pushing portion is not a rotational means but an up and down parallel moving means. However, such an apparatus moving up and down parallel the sheet pushing portion may generate impact sounds during parallel moving.
This invention is for solving the above problems. It is an object of the invention to provide a sheet feeding apparatus capable of reducing impact sounds even where a sheet pushing means operates and feeding sheets surely.
SUMMARY OF THE INVENTION
A representative structure according to the invention to accomplish the above object includes, in a sheet feeding apparatus for feeding sheets sheet by sheet separately from a placed sheet bundle, a sheet mounting portion for mounting sheets, a feeding rotary body for applying feeding force to the sheets, pushing means for pushing the sheet onto the feeding rotary body by moving in association with rotation of the feeding rotary body, and damper means for reducing impacts in connecting to a moving portion of the pushing means.
With the structure thus described, the pushing means operates with buffered impacts by the damper means even where the sheet pushing member of the pushing means is moved up and down parallel to make the apparatus compact, thereby reducing impact sounds.
The damper means may be constituted of an air damper, which operates to reduce air resistance when the pushing mean moves in a direction that the sheet is pushed toward the feeding rotary body, and thereby, the apparatus can reduce impact sound without increasing drive loads.
The sheet mounting portion or the sheet pushing member of the pushing means may be constituted having a friction coefficient of 0.1 or less with respect to a mounted sheet. A smaller frictional resistance on the sheet mount surface of the sheet mounting portion or the sheet pushing means allows sheets to be fed stably without exerting unnecessary force during sheet feeding.
A restricting portion for restricting a rear end of the mounted sheets from moving backward in a sheet conveyance direction is provided at the sheet mounting portion, thereby surely conveying the sheets.
Furthermore, an image forming means is attached to each sheet feeding apparatus described above as to form an image forming apparatus.
REFERENCES:
patent: 5537227 (1996-07-01), Samii
patent: 5676367 (1997-10-01), Oshino et al.
patent: 5897259 (1999-04-01), Ahn
patent: 5961113 (1999-10-01), Morris
patent: 6029970 (2000-02-01), Hwang
Grant II Jerome
Worku Negussie
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