Sheet feeding or delivering – Feeding – Separator and conveyor
Reexamination Certificate
2001-07-17
2003-05-20
Jillions, John M. (Department: 3654)
Sheet feeding or delivering
Feeding
Separator and conveyor
C271S010110, C271S117000
Reexamination Certificate
active
06565077
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper feed apparatus for sequentially transferring only an uppermost sheet out of sheets mounted on a paper feed tray in a stacked state at predetermined timing.
2. Description of the Related Art
There is proposed a paper feed apparatus of such a type as shown in FIG.
1
.
FIG. 1
is a schematic side elevational view of the proposed paper feed apparatus. A paper feed apparatus
100
includes a paper feed tray
102
for mounting many sheets
101
in a stacked state, primary paper feed device
103
for transferring only the uppermost sheet
101
on the paper feed tray
102
, and secondary paper feed device
106
for transferring the sheet
101
transferred by the primary paper feed device
103
to a portion between a printing drum
104
and a press roller
105
at predetermined timing.
The primary paper feed device
103
includes a scraper roller
107
press-contacted with the uppermost sheet
101
on the paper feed tray
102
, a stripper plate
108
arranged in the vicinity of the downstream side of the scraper roller
107
, and a pickup roller
109
substantially press-contacted with the stripper plate
108
. The scraper roller
107
and the pickup roller
109
are driven to rotate in the same direction by primary driving device (not shown). The secondary paper feed device
106
includes a pair of secondary paper feed rollers
110
arranged downstream of the primary paper feed device
103
in a sheet transfer direction, and a pair of guide members
112
and
113
providing a transfer path
111
between the members
112
and
113
in the vicinity of the paired secondary paper feed rollers
110
. The paired secondary paper feed rollers
110
are driven to rotate by secondary driving device (not shown). The upper guide member
112
guides only the neighborhood of the secondary paper feed roller
110
and the upstream side of the upper guide member
112
in the sheet transfer direction is formed as an inclined section
112
a
directed upward.
With the above-described constitution, when the scraper roller
107
and the pickup roller
109
are rotated, the uppermost sheet
101
on the paper feed tray
102
is applied with a transfer force and thereby transferred, whereby a sheet
101
under the uppermost sheet
101
is also transferred by frictional resistance between the sheet
101
and the uppermost sheet
101
. If the sheet
101
is transferred to a position at which the tip end of the sheet
101
enters between the stripper plate
108
and the pickup roller
109
, a plurality of sheets
101
are dealt with the stripper plate
108
and the transfer of sheets
101
other than the uppermost sheet
101
is stopped at the stripper plate
108
. At the same time, only the uppermost sheet
101
is transferred to a downstream side. When the sheet
101
thus transferred is guided by the guide member
113
and transferred to a position near the paired secondary paper feed rollers
110
, the sheet
101
enters the transfer path
111
between the paired guide members
112
and
113
. If the sheet
101
passes this transfer path
111
, the tip end of the sheet
101
is introduced to the portion between the paired secondary paper feed rollers
110
and, as shown in
FIG. 2
, the transfer of the sheet
101
is stopped in a state in which the tip end side of the sheet
101
is slightly bent. Next, the paired secondary paper feed rollers
110
are rotated synchronously with the rotation of the printing drum
104
. If the paired secondary paper feed rollers
110
are rotated, the sheet
101
which has been transferred to the portion between the paired secondary paper rollers
110
is applied with a transfer force and thereby transferred to the portion between the printing drum
104
and the press roller
105
at predetermined timing. The sheet
101
is transferred to the portion between the printing drum
104
and the press roller
105
while being press-contacted with the portion and printing is conducted to the sheet
101
in this press-contact transfer course.
Meanwhile, the paired guide members
112
and
113
introducing the tip end of the sheet
101
transferred by the primary paper feed device
103
to the portion between the paired secondary paper feed rollers
110
are set to have a constant distance h therebetween in the proposed paper feed apparatus.
However, if the distance h between the paired guide members
112
and
113
is set to be wide enough to allow a thick sheet to pass through the transfer path with a margin left, correction of sheet corrugation cannot be expected to be exerted to a thin sheet, a sheet with less flexibility or a largely corrugated sheet after being left for a while. As a result, the problem that the printed sheet
101
is wrinkled occurs. That is, as shown in
FIG. 3
, if the sheet
101
has a corrugated portion “a” and passes between the paired secondary paper feed rollers
110
without correcting this corrugated portion “a”, then the corrugated portion “a” is crushed between the paired secondary paper feed rollers
110
and the sheet
101
has wrinkles “b” as shown in FIG.
4
.
On the other hand, if the distance h between the paired guide members
112
and
113
is set to allow a thick sheet (including an envelope and the like) to pass between the paired guide members
112
and
113
narrowly, correction of sheet corrugation is expected to be exerted to a thin sheet, a sheet with less flexibility or a sheet corrugated after being left for a while. However, the problem that the thick sheet tends to clog occurs.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described problems. It is, therefore, an object of the present invention to provide a paper feed apparatus which does not cause paper clogging when thick sheets are used and which does not generate wrinkles on sheets if thin sheets are used.
The first aspect of the invention provides a paper feed apparatus comprising: a paper feed tray for mounting a plurality of sheets in a stacked state; primary paper feed device for sequentially transferring only the uppermost sheet out of the sheets on the paper feed tray; a pair of secondary paper feed rollers arranged downstream of the primary paper feed device in a sheet transfer direction, and a pair of guide members providing a transfer path between the pair of guide members near the pair of secondary paper feed rollers; secondary paper feed device for introducing tip ends of the sheets transferred by the primary paper feed device by using the pair of guide members to a portion between the paired secondary paper feed rollers, and for transferring the sheets introduced to the portion between the pair of secondary paper feed rollers to a transport downstream side according to rotation of the pair of secondary paper feed rollers; and guide distance adjustment device for making a distance between the pair of guide members variable, wherein the guide distance adjustment device comprises an operation member operated by a user, and the guide distance adjustment device makes the distance between the pair of guide members variable by operating the operation member.
According to the first aspect of the invention, if the sheets are thick, the distance between a pair of guide members is set wide, thereby transferring the sheets to the transfer path between the paired guide members with a margin left. If the sheets are thin sheets, sheets with less flexibility or the like, the distance between the paired guide members is set narrow. By doing so, the sheets are subjected to correction of sheet corrugation at the time of passing through the transfer path between the paired guide members and then introduced to the portion between a pair of secondary paper feed rollers. Due to this, it is possible to prevent wrinkles derived from the pressurization of corrugated portions by the paired secondary paper feed rollers. Furthermore, a user can freely, arbitrarily change the distance between the paired guide members in light of the thickness of the sheets to be use
Berkowitz Marvin C.
Jillions John M.
Nath Gary M.
Novick Harold L.
Riso Kagaku Corporation
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