Printing – Print plate feeding or delivering
Reexamination Certificate
2000-07-20
2002-06-04
Yan, Ren (Department: 2854)
Printing
Print plate feeding or delivering
C101S116000
Reexamination Certificate
active
06397750
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a stencil disposal unit and stencil disposal method, and more particularly to a stencil disposal unit and stencil disposal method in which a used stencil wound around the outer periphery of a printing drum of a rotary stencil printing machine is transported to a stencil disposal container or the like and then disposed.
Upon an investigation by the inventors of the present invention, a stencil disposal unit provided in a rotary stencil printing machine is envisioned, such as shown in
FIG. 8
, in which the stencil disposal unit
138
automatically disposes of a used stencil from a printing drum.
The stencil disposal unit
138
is disposed in proximity to the periphery of a printing drum
112
, and minimally has a pair of stencil disposal rollers
139
, which are in mutual contact and which rotate in mutually opposite directions. The stencil sheet M is fed in between the stencil disposal rollers
139
and transported and recovered in a stencil disposal container
140
to the rear thereof.
In this rotary stencil printing machine the prepared stencil sheet M is automatically fed to and wound around the printing drum
112
.
Specifically, as shown in
FIG. 8
, after a stencil sheet M is pulled out from a stencil sheet roll and, and a stencil is made from the stencil sheet M using a thermal printing head
107
, it is transported to the printing drum
112
. After transport to the printing drum
112
, the end part of the stencil sheet M is grabbed by the clamping plate
119
at the printing drum
112
, and wound around the outer periphery of the printing drum
112
by rotation of the printing drum
112
. When the fixing of the stencil sheet M to the printing drum
112
is completed, a cutter unit
111
cuts the stencil sheet M.
The stencil sheet M is formed by a thermoplastic resin film, such as a polyethylene terephthalate film, a vinylidene chloride film, a polyester film, or a polypropylene film or the like, to which an ink permeable porous sheet (porous tissue carrier), made of a natural fiber, a chemical fiber, a synthetic fiber, or a thin paper, non-woven cloth, silk gauze or the like that is a mixture thereof is adhered, thereby forming a thermally sensitive stencil sheet. For a rolled stencil sheet M such as shown in
FIG. 8
, the ink permeable porous sheet is disposed on the outside surface. When printing is done, the ink permeable porous sheet makes contact with the outer surface of the printing drum
112
.
When printing, the printing drum
112
is caused to rotate in the counterclockwise direction as shown in
FIG. 8
, the print paper (not shown in the drawing) being fed between the printing drum
112
and a pressure means (not shown in the drawing), which presses the print paper up against the image part of the stencil sheet M attached to the printing drum
112
. By doing this, ink fed by an ink feeding means (not shown in the drawing)within the printing drum
112
passes through an ink-permeable part on the outer wall of the printing drum
112
, and is transferred to the print paper via the perforation parts of the stencil sheet M so as to form an image thereon.
When the printing is completed, the disposal operation is performed by the stencil disposal unit
138
. When disposing the stencil sheet M, as shown in
FIG. 9
, a mechanism not shown in the drawing releases the grip of the clamping plate
119
on the stencil sheet M, thereby freeing up the end part of the stencil sheet M that had been held. The printing drum
112
is then caused to rotate in the counterclockwise direction shown in
FIG. 8
, so that the freed-up end part of the stencil sheet M is fed between the pair of stencil disposal rollers
139
, causing disposal of the stencil sheet M.
SUMMARY OF THE INVENTION
According to an investigation by the inventors, however, with the stencil disposal unit
138
, the freed-up end part of the stencil sheet M that had been held by the clamping plate
119
has a tendency to curl, as shown in FIG.
9
.
If the stencil sheet M curls, this curl can cause the end to miss the space between the pair of stencil disposal rollers
139
, so that it is not transported into the stencil disposal container
140
. Additionally, because of the curving tendency of the rolled stencil sheet M, the expansion of the ink permeable porous sheet making up the stencil sheet M due to humidity in the air, and the influence of temperature and static electricity, the curl of the end part of the stencil sheet M often tends to be in a direction away from the printing drum
112
. By the rotation of the printing drum
112
during stencil disposal, there is resistance that urges the curl to move further away from the printing drum
112
, thereby aggravating the problem of curl.
For this reason, it can be envisioned that, in the stencil disposal unit
138
, as shown in
FIG. 11
, an endless guide belt
145
is wound between a stencil disposal roller
139
a, which, of the pair of stencil disposal rollers
139
, is farther from the printing drum
112
, and a pulley
146
is disposed above the clamping plate
119
, so as to guide a curled end of the stencil sheet M to between the pair of stencil disposal rollers
139
. If this is done, the guide belt
145
is rotationally driven by the rotation of the stencil disposal rollers
139
.
Another arrangement that can be envisioned is, as shown in
FIG. 11
, to provide an air blower
160
that applies pressure to the printing drum
112
side of the end part of the stencil sheet M to be curled, the air flow from the air blower
160
guiding the end part of the stencil sheet M to between the pair of stencil disposal rollers
139
.
It is also possible to combine elements of the guide belt
145
and the air blower
160
.
However, as the investigation by the inventors progressed further it was understood that, in the configuration in which a guide belt
145
is provided in the stencil disposal unit
138
, the position at which the guide belt
145
is provided is very close to the clamping plate
119
, so that it interferes with the swinging range of the clamping plate
119
.
For this reason, when the clamping plate
119
is caused to swing, it is necessary to have an added moving mechanism such that the pulley
146
onto which the guide belt
145
is wound is moved about the stencil disposal rollers
139
as a center, so that the guide belt
145
does not come into contact with the clamping plate
119
.
While it can be envisioned that the stencil disposal unit
138
having the guide belt
145
be positioned at a distance from the clamping plate
119
, thereby eliminating the need for the added moving mechanism, when the stencil disposal unit
138
is moved away from the clamping plate
119
, because the angle through which the printing drum
112
is turned after the clamping plate
119
is released becomes larger, the rotation of the printing drum
112
as noted above results in a large resistance that urges the curl to move away from the printing drum
112
, so that it is not possible to establish the position of the end part thereof, leading to the problem of missed disposal operation.
If an air blower
160
is used, although this does not involve the swinging range of the clamping plate
119
, another moving mechanism for the motor required by the air blower
160
is still required. Additionally, making the air blower
160
itself small will reduce the air output, making it necessary to bring this device close to the clamping plate
119
.
Thus, in the investigation conducted by the inventors as to the stencil disposal unit
138
, it was understood that the adopting of a configuration for the purpose of preventing faulty disposal of a used stencil was limited in terms of the positional relationship with respect to the clamping plate
119
, making it difficult to achieve a suitable configuration.
The printing drum
112
is configuration to enable removal in the axial direction for the purpose of maintenance inspections or the like. In this type of configuration, if the clamping plate
119
and the stencil disp
Ishii Shigenori
Motoe Katsuro
Berkowitz Marvin C.
Nath Gary M.
Nath & Associates
Riso Kagaku Corporation
Yan Ren
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