Printing – Stenciling – Rotary machines
Reexamination Certificate
2001-09-28
2003-01-28
Evanisko, Leslie J. (Department: 2854)
Printing
Stenciling
Rotary machines
C101S116000, C101S129000, C101S184000
Reexamination Certificate
active
06510789
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a stencil printing machine and a method, and more particularly, to a stencil printing machine having two sets of printing sections in each of which a print medium is transferred through a path between a printing drum which carries thereon a stencil sheet and a pressure rotary member which is provided to the associated printing drum for thereby selectively carrying out a printing operation in a both sides printing mode and in a one side printing mode, and to a method of selectively carrying out a printing operation in a both sides printing mode and in a one side printing mode.
A stencil printing machine that enables a both sides printing operation with the use of two sets of printing sections is shown in FIG.
7
.
FIG. 7
shows an overall structure of the stencil printing machine for the both sides printing operation.
In
FIG. 7
, the stencil printing machine
100
is constructed of upstream and downstream stencil making sections
104
,
105
with respective thermal printing heads
102
,
103
for thermally perforating respective stencil sheets
101
,
101
on the basis of respective image data, an upstream printing section
109
wherein the stencil sheet
101
made in the upstream stencil making section
104
is mounted onto an upstream printing drum
106
and a print sheet
107
, which is fed thereto, is transferred through a path between the upstream printing drum
106
and a press roller
108
in a pressured contact relationship to transfer ink onto an upper surface (one surface) of the print sheet
107
during such a transfer step, a paper feed section
110
which feeds the print sheet
107
to the upstream printing section
109
, an upstream belt-conveyer transfer unit
111
located at a sheet discharge side of the upstream printing section and transferring the print sheet
107
to a downstream side with the action of a belt
121
, a downstream printing section wherein the stencil sheet
101
, which is made in the downstream stencil making section
105
, is mounted onto a downstream printing drum
112
and the print sheet, which is fed from the upstream belt conveyer transfer unit
111
, is transferred through a path between the printing drum
112
and a press roller
114
in a pressured contact relationship to transfer ink onto a lower surface (the other surface) of the print sheet
107
during such a transfer step, and a downstream belt-conveyer transfer unit
117
with a belt
122
located at a sheet discharge side of the downstream printing section
115
for transferring the print sheet
107
to a sheet discharge tray
116
located in a downstream side.
Further, the upstream and downstream printing sections
109
,
115
include squeegee rollers
123
,
123
located inside the printing drums
106
,
112
, respectively, and held in contact with inner surfaces of outer peripheral walls
106
a
,
112
a
of the respective printing drums
106
,
112
, doctor rollers
124
,
124
located in close proximity to the squeegee rollers
123
,
123
, respectively, to form respective given gaps relative thereto, and ink supply units
125
,
125
each for supplying ink to an each area between the rollers
123
,
124
, with the squeegee rollers
123
,
123
being arranged to rotate on inner peripheral surfaces of the outer peripheral walls
106
a
,
112
a
in association with rotations of the respective printing drums
106
,
112
. In addition, as the squeegee rollers
123
,
123
rotate with, the rotations of the printing drums
106
,
112
, the outer peripheral surfaces of the squeegee rollers
123
,
123
are adhered with ink in a given film thickness, with the adhered ink being.transferred to the outer peripheral walls
106
a
,
112
a
to allow ink to be supplied to an inner side of the print sheet
101
at all times.
Now, the both .sides printing operation is described below. Rotations of the printing drums
106
,
112
allow the print sheet
107
to be fed from the paper feed section
110
to the upstream printing drum
106
in synchronism with the rotation thereof. The print sheet
107
, thus fed to the printing drum
106
, is brought into pressured contact with the stencil sheet
101
of the printing drum
106
with the press roller
108
to allow ink image to be transferred onto the upper surface of the print sheet
107
, with the print sheet
107
, whose upper surface is printed, being peeled off from the outer peripheral wall of the printing drum
106
and being introduced to the upstream conveyer-belt transfer unit
111
. The upstream belt-conveyer transfer unit
111
causes the belt
121
to move for transferring the print sheet
107
with its lower surface remaining contact with the belt, thereby feeding the print sheet
107
from the most downstream side of the belt
121
to the downstream printing drum
112
. The print sheet
107
, thus fed to the downstream printing drum
106
, is then brought into pressured contact with the stencil sheet
101
of the printing drum
112
with the press roller
114
to transfer ink image onto the lower surface of the print sheet
107
, with the print sheet
107
, whose lower surface is printed, being peeled off from the outer peripheral wall of the printing drum
112
to be introduced to the downstream belt-conveyer transfer unit
117
. The downstream belt-conveyer transfer unit
117
causes the belt
122
to move for transferring the print sheet
107
from the most downstream side of the belt
122
to the sheet discharge tray
116
. The print sheet
107
thus discharged to the sheet discharge tray
116
is placed therein in the stacked state.
Also, such a stencil printing machine is disclosed in Japanese Patent Application Laid-Open Publication No. 8-90893.
In the aforementioned stencil printing machine for the both sides printing operation, it is desired to achieve a one side printing operation and, so, various attempts have been conducted in the related art. For example, one technology to achieve this end concerns the two printing drums
106
,
112
, one of which is mounted with a stencil sheet
101
which is perforated on the basis of image data, and the other one of which is mounted with a non-perforated stencil sheet
101
. With such arrangement, when executing the printing operation in the same manner as the both sides printing operation, the print sheet is transferred with ink at the printing section mounted with the perforated stencil sheet
101
whereas the print sheet is not transferred with ink at another printing section mounted with the non-perforated stencil sheet
101
, thereby achieving the one side printing operation.
An alternative approach to achieve the one side printing operation is to locate a transfer unit at the discharge side of the upstream printing section
109
to transfer the print sheet
107
in another route to the sheet discharge tray without directing the print sheet
107
to the downstream printing section
115
. With such a structure, during the one side printing mode, the print sheet
107
, which is printed in the upstream printing section
109
, is discharged in another route, thereby achieving the one side printing operation.
SUMMARY OF THE INVENTION
However, in the former one side printing technology, the presence of the need for mounting the non-perforated stencil sheet onto one of the printing drums induces the waste of the stencil sheets. In the latter one side printing technology, the presence of the need for additionally locating the transfer unit as an extra printing drum mechanism in another route specific for the one side printing operation is a major cause of an inherent large size in structure and an increase in manufacturing cost.
Since, further, the two printing drums
106
,
112
must be rotated in synchronism with one another while retaining a given rotational angular phase difference, it is a usual practice to employ a single drive source for rotating both of these printing drums. Accordingly, if the printing drum
106
(or
112
), which is not in charge of the one side printing operation, is rotated, this rotation of t
Berkowitz Marvin C.
Evanisko Leslie J.
Nath Gary M.
Novick Harold L.
Riso Kagaku Corporation
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