Printing – Processes – Position or alignment
Reexamination Certificate
1999-08-03
2001-04-10
Yan, Ren (Department: 2854)
Printing
Processes
Position or alignment
C101S401100
Reexamination Certificate
active
06213020
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a drawing apparatus and a drawing method of drawing an image on a plate mounted on an outer peripheral surface of a drum.
2. Description of the Background Art
Drawing apparatuses for drawing an image upon irradiation of a plate used for printing with light have been used. In a drum-type drawing apparatus, a plate is mounted on a recording drum which is rotatable in a primary scanning direction, and a recording head comprising a laser diode and the like is moved in a secondary scanning direction parallel to a rotary shaft of the recording drum, to draw an image on the plate.
FIG. 9
is a schematic perspective view of a recording drum in a conventional drawing apparatus. A plate
160
made of aluminum serving as a recording material is mounted on a recording drum
150
shown in
FIG. 9. A
front end clamp
170
for fixing one end of the plate
160
and a rear end clamp
180
for fixing the other end of the plate
160
are mounted on an outer peripheral surface of the recording drum
150
. The rear end clamp
180
contains a magnet, and is fixed by a magnetic force to a position, on the outer peripheral surface of the recording drum
150
, corresponding to the size of the plate
160
.
The recording drum
150
having the plate
160
attached thereto is rotated at relatively low speed around a rotary shaft
190
, so that an image is drawn on the surface of the plate
160
.
In the conventional drawing apparatus, positioning pins (not shown) for positioning the plate
160
are provided on the outer peripheral surface of the recording drum
150
. Positioning holes for a recording drum (hereinafter referred to as recording drum positioning holes) to be respectively fitted on the positioning pins are formed at one end of the plate
160
. In mounting the plate
160
on the recording drum
150
, the recording drum positioning holes of the plate
160
are respectively fitted on the positioning pins of the recording drum
150
. Accordingly, it is possible to accurately position the plate
160
on the outer peripheral surface of the recording drum
150
.
On the other hand, positioning pins for positioning the plate
160
are also provided on the body of a printing machine. The positions of the positioning pins differ depending on the specification of the printing machine. Therefore, in the plate
160
, positioning holes for a printing machine (hereinafter referred to as printing machine positioning holes) must be respectively formed in positions corresponding to the specification of the printing machine.
Generally after the image is drawn on the plate
160
by the drawing apparatus, the printing machine positioning holes are respectively formed in predetermined positions of the plate
160
on the basis of an end surface of the plate
160
using a punching machine. The plate
160
can be positioned on the body of the printing machine by respectively fitting the printing machine positioning holes formed in the plate
160
on the positioning pins of the printing machine.
However, the size of the plate
160
varies. When the printing machine positioning holes are formed on the basis of the end surface of the plate
160
after the image is drawn by the drawing apparatus, the relationship between the image formed on the plate
160
and the printing machine positioning holes varies. In this case, the shift in the position for printing must be corrected by shifting the plate
160
mounted on the body of the printing machine while seeing the results of the printing obtained by the printing machine using the plate
160
. Therefore, printing work becomes complicated.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a drawing apparatus capable of accurately positioning a plate in a printing machine irrespective of the variation in the size of the plate.
Another object of the present invention is to provide a drawing method in which a plate can be accurately positioned in a printing machine irrespective of the variation in the size of the plate.
A drawing apparatus for drawing an image on a plate used for a printing machine having a positioning portion according to one aspect of the present invention comprises a cylindrical drum having a rotary shaft, an outer peripheral surface on which the plate is mounted and a positioning portion provided on the outer peripheral surface, a driving device for rotating the drum around the rotary shaft, a drawing unit for drawing an image on the plate mounted on the outer peripheral surface of the drum, and a fitting portion forming device for forming in the plate a first fitting portion to be fitted to the positioning portion of the drum and a second fitting portion to be fitted to the positioning portion of the printing machine before the plate is mounted on the drum.
In the drawing apparatus, the positioning portion is provided on the outer peripheral surface of the drum. Before the plate is mounted on the drum, the first fitting portion to be fitted to the positioning portion of the drum and the second fitting portion to be fitted to the positioning portion of the printing machine are simultaneously formed in the plate by the fitting portion forming device.
Thereafter, the plate is mounted on the outer peripheral surface of the drum in a state where the first fitting portion of the plate is fitted to the positioning portion on the outer peripheral surface of the drum. It is possible to draw an image on the plate on the outer peripheral surface of the drum by the drawing unit while rotating the drum having the plate mounted thereon around the rotary shaft by the driving device. At the time of printing, the second fitting portion of the plate is fitted to the positioning portion of the printing machine, so that the printing is done using the plate.
The first fitting portion and the second fitting portion are thus simultaneously formed in the plate. The image is drawn by the drawing unit in a state where the first fitting portion of the plate is fitted to the positioning portion of the drum. Therefore, the relationship between the image formed on the plate and the second fitting portion can be kept constant irrespective of the variation in the size of the plate. Consequently, it is possible to accurately position the plate in the printing machine in doing the printing by the printing machine using the plate, so that the position of printing is not shifted. As a result, no work for correcting the shift in the position of printing is required, thereby improving the efficiency of the printing work.
The positioning portion of the drum may be a positioning pin, the positioning portion of the printing machine may be a positioning pin, the first fitting portion may be a first positioning hole to be fitted on the positioning pin of the drum, and the second fitting portion may be a second positioning hole to be fitted on the positioning pin of the printing machine.
In this case, when the plate is mounted on the drum, the plate can be positioned on the outer peripheral surface of the drum by fitting the first positioning hole of the plate on the positioning pin of the drum. When the printing is done, the plate can be accurately positioned in the printing machine by fitting the second positioning hole of the plate on the positioning pin of the printing machine.
The fitting portion forming device may comprise a plurality of punching units for forming the first and second positioning holes in the plate.
In this case, the first and second positioning holes are simultaneously formed in the plate by the plurality of punting units. Consequently, the relationship between the first positioning hole and the second positioning hole is kept constant, so that the relationship between the image formed on the plate and the second positioning hole is kept constant.
The fitting portion forming device may further comprise a supporting member disposed in a predetermined position, and a mounting member provided in the supporting member so as to be attachable or detachable and h
Kawada Toru
Kitawaki Shiro
Dainippon Screen Mfg. Co,. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Yan Ren
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