Printing – Stenciling – Rotary machines
Reexamination Certificate
1999-10-21
2001-05-22
Funk, Stephen R. (Department: 2854)
Printing
Stenciling
Rotary machines
C271S209000, C271S215000
Reexamination Certificate
active
06234076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming machine such that both sides printing can be easily conducted although structure of a sheet supplying device and a sheet discharging device is simple.
2. Description of the Related Art
A stencil printing machine will be explained as an example of the image forming machine.
FIG. 5
illustrates an example of a conventional stencil printing machine. A cylindrical printing drum
100
is rotatable around an axis
100
a
thereof. An ink permeable area is formed in a part of a peripheral wall of the printing drum
100
. Inside the printing drum
100
, an ink supplying means
100
b
is situated for supplying ink to an inner circumferential surface of the peripheral wall. A clamping device
101
is attached to an outer circumferential surface of the peripheral wall of the printing drum
100
for holding a leading end of a stencil sheet. The stencil sheet held by the clamping device
101
at the leading end thereof is wound around the outer circumferential surface of the printing drum
100
.
Beneath the printing drum
100
, a cylindrical opposing drum
102
is rotatably situated. The opposing drum
102
is rigid and not deformed during printing. The diameter of the opposing drum
102
is approximately identical to that of the printing drum
100
. An axis of the opposing drum
102
is parallel to the axis of the printing drum
100
. The opposing drum
102
is arranged so as to practically contact the printing drum
100
. A holding claw
103
is attached to an outer circumferential surface of the opposing drum
102
. A recess
104
is formed in the outer circumferential surface of the opposing drum
102
for avoiding interference with the clamping device
101
of the printing drum
100
.
The printing drum
100
and the opposing drum
102
are rotated in synchronization with each other and in directions opposite to each other. The drums convey a printing sheet while holding it therebetween, and conduct printing on it.
Above a sheet supplying table
105
, a sheet supplying roller
106
is situated. Between the sheet supplying roller
106
and the printing drum
100
, a timing roller
107
is situated. On a discharging side of the printing drum
100
, there are disposed a discharging claw,
108
for peeling the printing sheet from the opposing drum
102
, a pinch roller
109
, and a discharging roller
110
for conveying the printing sheet. The printing sheet as printed is fed out by the discharging roller
110
onto a sheet discharging table
113
.
According to the conventional stencil printing machine as explained above, the printing sheet is taken by the sheet supplying roller
106
and the timing roller
107
, held by the holding claw
103
of the opposing drum
102
at the leading end thereof, and then conveyed along the outer circumferential surface of the opposing drum
102
upon rotation of the opposing drum
102
. And, the printing sheet is printed while being held between the printing drum
100
and the opposing drum
102
. The printing sheet as printed is released from the holding claw
103
and sent out by the discharging roller
110
onto the discharging table
113
.
The conventional stencil printing machine includes a driving mechanism for vertically moving the sheet supplying table
105
. Further, the printing machine includes a detecting means for detecting height of the printing sheets stacked on the sheet supplying table
105
. This constitution allows the printing sheet on the sheet supplying table
105
to be situated to an optimum position for being sent out by the sheet supplying roller
106
.
Further, the printing machine includes a driving mechanism for vertically moving the sheet discharging table
113
. Further, the printing machine includes a detecting means for detecting height of the printing sheets stacked on the sheet discharging table
113
. That constitution allows the discharging table
113
to be situated to a position such that the printing sheet as printed is discharged onto the sheet discharging table
113
without crimping and jamming so that the discharged sheets are orderly stacked.
However, according to the conventional stencil printing machine as explained above, the sheet supplying table
105
and the sheet discharging table
113
are situated to a front and a rear side of the printing drum
100
and the opposing drum
102
, respectively, in a direction of conveying the printing sheet. Therefore, the driving mechanism and the detecting means are required to be provided to each of the sheet supplying table
105
and the sheet discharging table
113
. Further, a control means is necessary for each of the sheet supplying table
105
and the sheet discharging table
113
for controlling movement of them. Further, enough space must be ensured for each of the sheet supplying table
105
and the sheet discharging table
113
for allowing them to move vertically. Additionally, the sheet supplying table
105
includes an adjustable sheet supplying fence
115
for guiding an outer edge of the printing sheet, and the sheet discharging table
113
includes an adjustable sheet discharging fence
116
for guiding the outer edge of the printing sheet. And, the sheet supplying fence
115
and the sheet discharging fence
116
must be adjusted according to a size of the printing sheet, respectively.
Further more, in the case where both sides of the printing sheet is needed to be printed, after the printing sheets are printed on one surface thereof, the printing sheets stacked on the sheet discharging table
113
are taken therefrom to be replaced on the sheet supplying table
105
upside-down. However, such operation that the printing sheets are moved from one table to another is troublesome. And, during the operation, the stacked sheets may shift to be rubbed with each other, thereby being deteriorated in printed image quality.
An object of the present invention is to provide an image forming machine of simple constitution that is capable of conducting optimum sheet supplying/discharging operations by moving the sheet supplying/discharging tables interlocked with each other and facilitating handling of the printing sheets during both sides printing.
SUMMARY OF THE INVENTION
An image forming machine defined in a first aspect of the present invention comprises an image forming section for receiving a sheet supplied in a supplying direction, printing an image on the sheet, and discharging the printed sheet in a discharging direction opposite to the supplying direction while changing the sheet upside-down; a sheet supplying table situated adjacent to the image forming section, the sheet supplying table stacking the sheet to be supplied to the image forming section; a sheet discharging table situated adjacent to the image forming section and disposed vertically relative to the sheet supplying table, the sheet discharging table stacking the sheet having the image printed thereon and discharged from the image forming section; and driving mechanism attached to the sheet supplying table and the sheet discharging table for vertically moving the sheet supplying table and the sheet discharging table in directions opposite to each other.
According to an image forming machine as defined in a second aspect of the present invention, in the image forming machine of the first aspect, the image forming machine further comprises sheet cassettes detachably attached to the sheet supplying table and the sheet discharging table for stacking the sheet thereon.
According to an image forming machine as defined in a third aspect of the present invention, in the image forming machine of the second aspect, the sheet cassette at the sheet discharging table and the sheet cassette at the sheet supplying table are exchangeable so that after the sheet supplied from the sheet cassette at the sheet supplying table is printed on one surface thereof by the image forming section and discharged to the sheet cassette at the sheet discharging table, the sheet cassettes at the sheet discharging table and
Kuratani Yasushi
Mizutani Tomohiro
Nogi Hideaki
Funk Stephen R.
Kanesaka & Takeuchi
Riso Kagaku Corporation
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