Printing – Stenciling – Rotary machines
Reexamination Certificate
2000-11-08
2002-05-07
Evanisko, Leslie J. (Department: 2854)
Printing
Stenciling
Rotary machines
C101S128100, C101S415100
Reexamination Certificate
active
06382095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of rotary stencil printer, and more particularly to a device for mounting a leading end of a stencil to the printing drum of a rotary stencil printer.
2. Description of the Prior Art
A full automatic rotary stencil printer having a basic construction such as shown in
FIG. 1
is already known. In
FIG. 1
,
10
is a printing drum which is driven to rotate anti-clockwise as shown by an arrow by printing drum driving means not shown in the figure when a stencil is mounted to the printing drum, also when the printing is carried out, and also when the used stencil is exhausted from the printing drum.
A stencil leading end mounting device generally designated by
12
in which the present invention is incorporated is provided at a part of the printing drum
10
.
14
is a roll of a band stencil sheet providing a stencil sheet supply source. The stencil sheet drawn out from the roll
14
is conducted through a guide passage
16
, between a thermal head
18
and a platen roller
20
, the thermal head
18
perforating the stencil sheet to form a stencil according to image data based upon an electric image data signal supplied thereto from image data processing means not shown in the figure, a cutter
22
in an open state, a movable passage
24
adapted to be positioned horizontal for receiving the leading end of the stencil and thereafter to break down at a break point
25
to be inclined as shown by phantom lines in the figure for giving an allowance in the feed of the stencil, and between stencil feed rollers
26
and
28
which feed the stencil so that the leading end thereof proceeds into the stencil leading end mounting device
12
under a controlled feed rate through a passage
30
and a movable stencil guide lip
32
.
After the leading end of the stencil has been fastened by the stencil leading end mounting device
12
, the succeeding part of the stencil perforated by a further operation of the thermal head
18
is first slackened for each predetermined length corresponding to a stroke of swing of the movable passage
24
about the break point
25
, while the printing drum
10
is intermittently driven in synchronization therewith to take up each allowance provided by the slackened stencil so that the stencil is gradually mounted around the printing drum
10
.
The stencil feed rollers
26
and
28
are put into idling, after the leading end of the stencil has been fastened by the stencil leading end mounting device
12
. When a predetermined amount of stencil has been fed, the cutter
22
is operated to cut out a sheet of stencil from the continuous band stencil sheet.
When a sheet of perforated stencil has been mounted around the printing drum
10
, the printer proceeds to a printing process, wherein print sheets are successively supplied from a print sheet supply tray not shown in the figure and are fed through between print sheet feed rollers
34
and
36
to a nipping region
40
between the printing drum
10
and a press roller
38
.
A squeeze roller
42
is provided in the printing drum
10
to oppose the nipping region and to be driven anti-clockwise as shown by the arrow in the figure in synchronization with the rotation of the printing drum
10
. A doctor rod
44
is provided adjacent the squeeze roller
42
to define a groove
46
to hold an ink deposit
52
formed by ink
50
supplied from an ink distributor
48
.
An agitation rod
54
is provided in the groove
46
at a central position thereof to provide a core of the ink deposit
52
, so that the ink deposit
52
forms a rotating mass of ink rotating clockwise around the agitation rod
54
when the squeeze roller
42
rotates anti-clockwise as viewed in the figure, with a part of the rotating mass of ink being successively drawn out therefrom in the form of an ink layer
56
carried on the squeeze roller
42
to be supplied to the inner circumferential surface of the printing drum
10
, this ink being further passed through the perforations of the stencil mounted around the printing drum
10
and transferred onto the print sheet fed through the nipping region
40
to form a stencil print image on the print sheet.
The print sheet thus applied with the stencil printing tends to move along the outer circumferential surface of the printing drum
10
due the adhesiveness of the ink, but the print sheet is removed from the outer circumferential surface of the printing drum as peeled off therefrom by a print sheet removal claw
58
and is transferred by a belt conveyer type print sheet discharge means
60
toward a printed sheet receiving tray not shown in the figure.
When the stencil mounted around the printing drum
10
is to be exhausted, the stencil leading end mounting device
12
is operated in a manner described in detail hereinbelow, so that the leading end of the stencil is released from the clamping by stencil leading end mounting device
12
and is brought into a state freely placed thereon.
Then the printing drum
10
is rotated in the direction shown by the arrow for the exhausting of the stencil such that the leading end of the stencil is scooped up by a stencil removal claw
62
when it traverses the tip end of the claw and is then bitten into between belt conveyers
64
and
66
of a stencil exhausting means, each of which-is moving in the direction shown by arrows, thus the stencil being successively peeled off from the printing drum
10
as the printing drum
10
is further rotated, to be finally exhausted into a stencil exhaust box positioned on the left side of the belt conveyers
64
and
66
though not shown in the figure.
A belt conveyer
68
operates to guide the leading end of the stencil toward a nipping region between the belt conveyers
64
and
66
if the leading end of the stencil would divert away from the nipping region.
With respect to a rotary stencil printer having such a known basic construction, in U.S. Pat. No. 5,575,204 owned by the same assignee as the present application, there has been proposed an improved construction of the stencil leading end mounting device
12
such as shown in
FIGS. 2 and 3
a-
3
h.
In these figures, the stencil leading end mounting device
12
comprises a base member
72
having a band surface
70
working as a stencil leading end supporting surface, the band surface extending along a portion of the cylindrical outer surface of the printing drum
10
along a generatrix of the printing drum in parallel with the central axis thereof and incorporating a magnet piece (desirably a rubber magnet piece) planted therein, and a clamp member
76
having a clamping surface
74
and movable between a closed position (the position shown in FIG.
2
and
FIG. 3
a
) where the clamping surface is laid over the stencil leading end supporting surface
70
and an open position (the position shown in
FIG. 3
b
) where the clamping surface is removed from the stencil leading end supporting surface
70
.
The clamp member
76
is a plate element of a magnetic material having an elongated rectangular shape extending in parallel with the central axis of the printing drum, and is pivotably supported at longitudinally opposite end portions by a pair of bearing means
78
mounted to the base member
72
, so as to be movable between the above-mentioned closed and open positions. The clamp member
76
is constantly magnetically attracted toward the closed position by the above-mentioned magnet piece. The clamp member
76
has a plurality of ribs
80
spaced along the upper surface of the plate element forming the principal portion of the clamp member. Further, the plate element forming the principal portion of the clamp member
76
includes a lever portion
82
at one longitudinal end thereof.
The stencil leading end mounting device
12
further comprises a snap-up member
88
which, in the shown construction, is formed of a rod element
84
and a pair of arm elements
86
firmly mounted at opposite ends of the rod element. The snap-up member is movable such that the part formed by the rod
Evanisko Leslie J.
Oliff & Berridg,e PLC
Riso Kagaku Corporation
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