Sheet feeding or delivering – Feeding – Separators
Utility Patent
1997-12-15
2001-01-02
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S124000, C271S161000, C271S167000
Utility Patent
active
06168150
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a sheet feeder unit which supplies cut sheets set in a pile thereon by a feeding roller being contacted to the cut sheets from one side thereof, and particularly to a sheet feeder unit which is capable of separating cut sheets to be supplied one after another by a frictional force generated when a leading end of the cut sheet is pushed forward to contact a friction member which is supported at one end thereof and extended toward a conveying path of the cut sheet. The present invention may be employed for feeding a plurality of piled cut sheets one by one in various appliances such as a copying machine, printer, facsimile machine, or image reading apparatus.
2. Description of Related Art
Japanese published unexamined patent application No.7-196186 discloses such a sheet feeder unit, which is shown in FIG.
7
. The feeder unit according to this prior art has a friction member
133
rotatably supported at its lower end by a shaft
132
to be able to stand upright and tilt, and configured to be rectangular when viewed from the front. Each time a feeding roller
131
is rotated round, an uppermost cut sheet
111
is pushed forward so that a whole width of a leading end of the cut sheet
111
comes into frictional contact with the friction member
133
and causes the same to back away against a restoring force of a spring
134
as shown by phantom lines in FIG.
7
. The cut sheet
111
is thereby separated from the others and prevented from being supplied one upon another.
In order to assure the separation of cut sheets from each other, the angle &agr; made by a surface of the friction member
133
and an uppermost cut sheet
111
is set within the range of 55° to 85°.
The above mentioned published application also teaches a friction member made of an elastic sheet and fixed at its lower end with the same angular condition as described above, instead of rotatable support by the shaft
132
.
The friction member of such configuration, however, requires a very fine adjustment to successfully separate the cut sheets. According to an experiment conducted by the inventors of the present invention, the restoring force of the spring
134
toward its initial position should be set weak to prevent residual deformation of the cut sheet caused by the friction member
133
. On the other hand, the restoring force should be strong enough to increase the frictional force between the cut sheet
111
and the friction member
133
so as to ensure the separation. It is difficult to satisfy both of these contradictory conditions. Moreover, the resiliency of cut sheets varies depending on their quality and thickness, causing differences in frictional resistance even with the use of the same friction member.
Also, the friction member
133
in this prior art arrangement is disposed downstream in a feeding direction and away from a nipping position where the feeding roller
131
presses and pushes the cut sheet
111
forward. The cut sheet, when contacted against the friction member
133
, is warped and separated from the other. Since the friction member
133
is distanced from the feeding roller
131
widely enough to allow the cut sheet
111
to flexibly deform therebetween, the cut sheet
111
can easily escape from the friction member
133
which is being tilted backward. This configuration helps to prevent residual deformation of the cut sheets
111
irrespective of their thickness.
Still, the sheet feeder unit of this prior art is not fully capable of stably separating cut sheets
111
and sometimes supplies the cut sheets in plural one upon another for the following reasons. Since the friction member
133
has an even surface against which the cut sheet
111
is contacted, the more the leading end of the cut sheet
111
pushes the friction member
133
and approaches a free end thereof, the more the contacting angle therebetween widens, to let the cut sheet
111
to easily slip, causing the frictional force to become less than a desired degree. The cut sheets
111
thus slip through the friction member
133
from time to time without being fully separated from each other. Although the setting of the angle between the cut sheet
111
and the friction member
133
helps to prevent such slippage to some extent, it is not enough to fully prevent faulty feeding of cut sheets, especially of a less resilient type due to their quality or thickness.
BRIEF SUMMARY OF THE INVENTION
In view of the foregoing, it is a primary object of the present invention to provide a sheet feeder unit being capable of successfully separating and supplying cut sheets of any thickness.
To accomplish the said object, the sheet feeder unit of the present invention comprises a support member on which a plurality of sheets piled on one another are loaded; a feeding roller which is contacted to one side of the sheets piled on the support member for causing the sheets to advance in a sheet feeding direction; and a friction member being supported at one end and having a plurality of frictional portions which are capable of contacting a leading edge of the sheets sent out by the feeding roller in the sheet feeding path.
According to such arrangement of the present invention, the leading edge of the sheet is provided with necessary frictional force of contact until it is freed from the tip of the friction member, by each of the frictional portions respectively deforming according to the intricate curve of the cut sheet, whereby the sheets of any thickness can be positively separated from each other without residual deformation and stably supplied one by one.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
REFERENCES:
patent: 5026042 (1991-06-01), Miller
patent: 5377970 (1995-01-01), Kikuchi
patent: 5485991 (1996-01-01), Hirano et al.
patent: 5520381 (1996-05-01), Lo et al.
patent: 5527029 (1996-06-01), Bortolotti et al.
patent: 5626334 (1997-05-01), Kondo et al.
patent: 5711519 (1998-01-01), Bortolotti
patent: 5769411 (1998-06-01), Nakagawa et al.
patent: 5813669 (1998-09-01), Horii
patent: 3508270 (1986-09-01), None
patent: 0694491 (1996-01-01), None
patent: 0694490 (1996-01-01), None
patent: 0697358 (1996-02-01), None
patent: 0145946 (1980-11-01), None
patent: 0202228 (1983-11-01), None
patent: 0264140 (1987-11-01), None
patent: 0026618 (1991-02-01), None
patent: 403264431A (1991-11-01), None
patent: 7-196186 (1995-08-01), None
Hori Haruhiko
Nakamura Yasuo
Minolta Co. , Ltd.
Sidley & Austin
Skaggs H. Grant
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