Title: Printing machine
Abstract: A recording head moving mechanism has a pair of guide rails fixed to a support member, and a ball screw extending parallel to the guide rails. The ball screw is rotatable by a motor to move a recording head parallel to an axis of a plate cylinder. At an image-recording time, the recording head records an image while being moved at a constant speed by the moving mechanism through a moving region between a recording start position and a recording finish position. After recording the image, the recording head is moved to a retreat position.
Patent Number: 6,901,860 Issued on 06/07/2005 to Ito
| Inventors:
|
Ito; Shinji (Kyoto, JP)
|
| Assignee:
|
Dainippon Screen Mfg. Co., Ltd. (Kyoto, JP)
|
| Appl. No.:
|
689590 |
| Filed:
|
October 22, 2003 |
Foreign Application Priority Data
| Nov 11, 2002[JP] | 2002-326208 |
| Jul 17, 2003[JP] | 2003-198246 |
| Current U.S. Class: |
101/463.1; 101/401.1; 101/465 |
| Intern'l Class: |
B41N 003/00 |
| Field of Search: |
101/4011,463.1,465-467
|
References Cited [Referenced By]
U.S. Patent Documents
| 6050188 | Apr., 2000 | Bolza-Schunemann.
| |
| 6470799 | Oct., 2002 | Nakazawa et al.
| |
| 6502509 | Jan., 2003 | Gottling et al.
| |
| 6510795 | Jan., 2003 | Detmers et al.
| |
| 6543348 | Apr., 2003 | Onuma et al.
| |
| 6668720 | Dec., 2003 | Jentzsch.
| |
| 2002/0053295 | May., 2002 | Jentzsch.
| |
| Foreign Patent Documents |
| 0 949 071 | Oct., 1999 | EP.
| |
| P2000-301689 | Oct., 2000 | JP.
| |
| P2001-322233 | Nov., 2001 | JP.
| |
| P2001-322234 | Nov., 2001 | JP.
| |
| P2001-322235 | Nov., 2001 | JP.
| |
| P2001-322238 | Nov., 2001 | JP.
| |
| P2002/-29023 | Jan., 2002 | JP.
| |
Primary Examiner: Hirshfeld; Andrew H.
Assistant Examiner: Culler; Jill E.
Attorney, Agent or Firm: McDermott Will & Emery LLP
Claims
1. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising:
a plate cylinder for supporting a printing plate as mounted peripherally thereof;
an image recorder having a recording head movable along a surface of said plate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a shielding plate disposed between said moving region and said retreat position,
and defining an opening for allowing passage of said recording head; and
a gas jet nozzle for forming an air curtain along said opening as a barrier between
said retreat position and said moving region.
2. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising:
a plate cylinder for supporting a printing plate as mounted peripherally thereof:
an image recorder having a recording head movable along a surface of said plate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a shielding plate disposed between said moving region and said retreat position,
and defining an opening for allowing passage of said recording head; and
a shielding door for opening and closing said opening of said shielding plate.
3. A printing machine as defined in claim 2, wherein said shielding door is attached
to a position of said recording head opposed to said moving region when said recording
head is in said retreat position, for closing said opening of said shielding plate
when said recording head is in said retreat position.
4. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising:
a plate cylinder for supporting a printing plate as mounted peripherally thereof;
an image recorder having a recording head movable along a surface of said plate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a shielding plate disposed between said moving region and said retreat position,
and defining an opening for allowing passage of said recording head; and
gas flow forming means for forming a gas flow directed from said retreat position
toward said moving region.
5. A printing machine as defined in claim 4, wherein said gas flow forming means
includes a chamber for enclosing said recording head moved to said retreat position,
said chamber defining an opening opposed to said moving region for allowing passage
of said recording head, and a fan for drawing a gas from outside said printing
machine into said chamber.
6. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising:
a plate cylinder for supporting a printing plate as mounted peripherally thereof;
an image recorder having a recording head movable along a surface of said plate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a chamber for enclosing said recording head moved to said retreat position, said
chamber defining an opening opposed to said moving region for allowing passage
of said recording head; and
a gas jet nozzle for forming an air curtain along said opening as a barrier between
inside of said chamber and outside of said chamber.
7. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising;
a plate cylinder for supporting a printing plate as mounted peripherally thereof;
an image recorder having a recording head movable along a surface of said plate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a chamber for enclosing said recording head moved to said retreat position, said
chamber defining an opening opposed to said moving region for allowing passage
of said recording head; and
a shielding door for opening and closing said opening of said chamber.
8. A printing machine as defined in claim 7, wherein said shielding door is attached
to a position of said recording head opposed to said moving region when said recording
head is in said retreat position, for closing said opening of said chamber when
said recording head is in said chamber.
9. A printing machine for recording an image on a printing plate, and printing
the image by using the printing plate with the image recorded thereon, comprising;
a plate cylinder for supporting a printing plate as mounted peripherally thereof;
an image recorder having a recording head movable along a surface of said elate
cylinder in a direction parallel to an axis of rotation of said plate cylinder
for recording an image on said printing plate mounted peripherally of said plate
cylinder;
an ink feeder for feeding ink to said printing plate with the image recorded
thereon mounted peripherally of said plate cylinder;
a printing means for printing an image on a printing sheet by using the printing
plate with an ink fed;
retreat moving means, operable at a printing time, for moving said recording
head to a retreat position sideways from a moving region where said recording head
is moved at an image-recording time;
a chamber for enclosing said recording head moved to said retreat position, said
chamber defining an opening opposed to said moving region for allowing passage
of said recording head; and
gas flow forming means for forming a gas flow directed from inside of said chamber
toward outside of said chamber.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a printing machine for making a printing plate by
recording and developing an image on the plate, and thereafter printing the image
by feeding ink to the plate.
2. Description of the Related Art
In an ordinary conventional printing machine, a prepress process is carried out
first to make a printing plate by exposing the plate placed in contact with a film
having a binary black and white image recorded thereon. Then, the plate is loaded
into a printing apparatus to carry out a printing process.
Recently, printing machines commonly called digital printers have been
proposed, one such printer being capable of performing both the prepress process
and printing process. A digital printer, as described in U.S. Pat. No. 6,050,188,
for example, employs a "computer-to-plate" system for forming an image on a printing
plate by directly scanning and exposing the plate with laser beams or the like
modulated with image signals.
A printing machine as described in U.S. Pat. No. 6,050,188 has, arranged in the
same space, plate cylinders for holding printing plates mounted peripherally thereof,
blanket cylinders with blankets mounted peripherally thereof, an impression cylinder,
image recorders for recording images on the printing plates mounted peripherally
of the plate cylinders, and ink feeders for feeding inks to the printing plates
mounted peripherally of the plate cylinders. A recording head is disposed close
to each plate cylinder for recording images on the printing plate mounted peripherally
of the plate cylinder.
In the printing machine capable of performing both the prepress process and printing
process described above, the recording head is disposed around each plate cylinder
even at a printing time. Mists and particles of the inks, water, paper and so on
floating in the printing machine tend to adhere to the recording head, The quantity
of light for recording could thereby be reduced to record defective images. This
results in the inconvenience of having to clean the recording head periodically.
SUMMARY OF THE INVENTION
The object of this invention, therefore, is to provide a printing machine that
minimizes adhesion to a recording head of inks, water, paper particles and so on,
thereby to reduce the frequency of cleaning the recording head.
The above object is fulfilled, according to this invention, by a printing machine
for recording an image on a printing plate, and printing the image by using the
printing plate with the image recorded thereon, comprising a plate cylinder for
supporting a printing plate as mounted peripherally thereof, an image recorder
having a recording head movable along a surface of the plate cylinder in a direction
parallel to an axis of rotation of the plate cylinder for recording an image on
the printing plate mounted peripherally of the plate cylinder, an ink feeder for
feeding ink to the printing plate mounted peripherally of the plate cylinder and
having the image recorded by the image recorder, and a moving device, operable
at a printing time, for moving the recording head to a retreat position sideways
from a moving region where the recording head is moved at an image-recording time.
This printing machine, with the moving device operable at a printing time for
moving the recording head to the retreat position sideways from the moving region
where the recording head is moved at an image-recording time, can prevent adhesion
to the recording head of inks, water, paper particles and so on. Thus, the frequency
of cleaning the recording head may be reduced.
In one preferred embodiment, the printing machine has a shielding plate disposed
between the moving region and the retreat position, and defining an opening for
allowing passage of the recording head.
Preferably, the shielding plate is a side plate for rotatably supporting
the plate cylinder.
In one preferred embodiment, the printing machine has a gas flow forming device
for forming a gas flow directed from the retreat position toward the moving region.
Preferably, the gas flow forming device includes a chamber for enclosing
the recording head moved to the retreat position, the chamber defining an opening
opposed to the moving region for allowing passage of the recording head, and a
fan for drawing a gas from outside the printing machine into the chamber.
Other features and advantages of the invention will be apparent from the following
detailed description of the embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purpose of illustrating the invention, there are shown in the drawings
several forms which are presently preferred, it being understood, however, that
the invention is not limited to the precise arrangement and instrumentalities shown.
FIG. 1 is a schematic view of a printing machine according to this invention;
FIG. 2 is a perspective view of a principal portion of an image recorder in
a first embodiment of this invention;
FIG. 3 is a perspective view of a principal portion of an image recorder in
a second embodiment of this invention;
FIG. 4 is a perspective view of a principal portion of an image recorder in
a third embodiment of this invention;
FIG. 5 is a perspective view of a principal portion of an image recorder in
a fourth embodiment of this invention;
FIG. 6 is a schematic side view showing movement of a recording head of the
image recorder in the fourth embodiment;
FIG. 7 is a perspective view of a principal portion of an image recorder in
a fifth embodiment of this invention; and
FIG. 8 is a schematic sectional view showing a chamber interior of the image
recorder in the fifth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of this invention will be described hereinafter with reference
to the drawings. FIG. 1 is a schematic view of a printing machine according to
the invention.
This printing machine makes printing plates by recording and developing images
on blank plates mounted on first and second plate cylinders
11 and
12,
feeds inks to the plates having the images recorded thereon, and transfers the
inks from the plates through first and second blanket cylinders
13 and
14
to printing paper mounted on an impression cylinder
15, thereby printing
the images on the printing paper.
The first blanket cylinder
13 is contactable with the first plate cylinder
11, while the second blanket cylinder
14 is contactable with the
second plate cylinder
12. The impression cylinder
15 is contactable
with the first and second blanket cylinders
13 and
14 in different
positions. The machine further includes a paper feed cylinder
16 for transferring
printing paper supplied from a paper magazine
27 to the impression cylinder
15, a paper discharge cylinder
17 with chains
19 wound thereon
and on a sprocket
18 for discharging printed paper from the impression cylinder
15 to a paper discharge station
28.
The impression cylinder
15 contactable by the first and second blanket
cylinders
13 and
14 has half the diameter of the first and second
plate cylinders
11 and
12 and the first and second blanket cylinders
13 and
14. Further, the impression cylinder
15 has a gripper,
not shown, for holding and transporting the forward end of printing paper.
The paper feed cylinder
16 disposed adjacent the impression cylinder
15
has the same diameter as the impression cylinder
15. The paper feed cylinder
16 has a gripper, not shown, for holding and transporting the forward end
of each sheet of printing paper fed from the paper magazine
27. When the
printing paper is transferred from the feed cylinder
16 to the impression
cylinder
15, the gripper of the impression cylinder
15 holds the
forward end of the printing paper which has been held by the gripper of the feed
cylinder
16.
The paper discharge cylinder
17 disposed adjacent the impression cylinder
15 has the same diameter as the impression cylinder
15. The discharge
cylinder
17 has a pair of chains
19 wound around opposite ends thereof.
The chains
19 are interconnected by coupling members, not shown, having
grippers arranged thereon. When the impression cylinder
15 transfers the
printing paper to the discharge cylinder
17, one of the grippers of the
discharge cylinder
17 holds the forward end of the printing paper having
been held by the gripper of the impression cylinder
15. With movement of
the chains
19, the printing paper is discharged to the paper discharge station
28.
The impression cylinder
15 is connected to a drive motor
10 through
a belt
22. The impression cylinder
15, feed cylinder
16, discharge
cylinder
17 and first and second blanket cylinders
13 and
14
are connected to one another through gears attached to ends thereof, respectively.
Further, the first blanket cylinder
13 is connected to the first plate cylinder
11, and the second blanket cylinder
14 to the second plate cylinder
12 by gears attached to ends thereof, respectively, when the first and second
blanket cylinders
13 and
14 are in printing positions described hereinafter.
Thus, the drive motor
10 rotates the feed cylinder
16, impression
cylinder
15, discharge cylinder
17, first and second blanket cylinders
13 and
14, and first and second plate cylinders
11 and
12
synchronously with one another.
The first plate cylinder
11 has, arranged therearound, an ink feeder
20a
for feeding black ink (K), for example, to a plate, an ink feeder
20b
for feeding magenta ink (M) to a different plate, and dampening water feeders
21a and
21b for feeding dampening water to the plates.
The second plate cylinder
12 has, arranged therearound, an ink feeder
20c
for feeding cyan ink (C) to a plate, an ink feeder
20d for feeding
yellow ink (Y) to a different plate, and dampening water feeders
21c
and
21d for feeding dampening water to the plates.
Further, the first and second plate cylinders
11 and
12 have,
arranged therearound, a plate feeder
23 for feeding plates to the periphery
of the first plate cylinder
11, a plate feeder
24 for feeding plates
to the periphery of the second plate cylinder
12, an image recorder
25
for recording images on the plates mounted peripherally of the first plate cylinder
11, an image recorder
26 for recording images on the plates mounted
peripherally of the second plate cylinder
12, and a plate discharger
29
common to the first and second plate cylinders
11 and
12.
Each of the image recorders
25 and
26 includes a recording head
moving mechanism for moving a recording head to a retreat position. The recording
head moving mechanism will be described in detail hereinafter.
In the printing machine having the above construction, a printing plate drawn
from a supply cassette
31 in the plate feeder
23 is cut to a predetermined
size by a cutter
32. A forward end of the printing plate cut into sheet
form is guided by guide rollers and a guide member, and clamped by a clamping jaw
on the first plate cylinder
11. Then, the first plate cylinder
11
is rotated by a motor, whereby the printing plate is wound peripherally of the
first plate cylinder
11. The rear end of the printing plate is clamped by
a different clamping jaw. While, in this state, the first plate cylinder
11
is rotated at low speed by the motor, the image recorder
25 irradiates the
surface of the plate mounted peripherally of the first plate cylinder
11
with a modulated laser beam for recording an image thereon.
Similarly, a printing plate drawn from a supply cassette
33 in
the plate feeder
24 is cut to a predetermined size by a cutter
34.
A forward end of the printing plate cut into sheet form is guided by guide rollers
and a guide member, and clamped by a clamping jaw on the second plate cylinder
12. Then, the second plate cylinder
12 is rotated by a motor, whereby
the printing plate is wound peripherally of the second plate cylinder
12.
The rear end of the printing plate is clamped by a different clamping jaw. While,
in this state, the second plate cylinder
12 is rotated at low speed by the
motor, the image recorder
26 irradiates the surface of the plate mounted
peripherally of the second plate cylinder
12 with a modulated laser beam
for recording an image thereon.
The first plate cylinder
11 holds two printing plates mounted peripherally
thereof, one for printing in the black ink and the other in the magenta ink. These
two printing plates are arranged in evenly separated positions, i.e. in positions
separated from each other by 180 degrees. The image recorder
25 records
images on these printing plates. Similarly, the second plate cylinder
12
holds two printing plates mounted peripherally thereof, one for printing in the
cyan ink and the other in the yellow ink. These two printing plates also are arranged
in evenly separated positions. The image recorder
26 records images on these
printing plates to complete a platemaking process.
The platemaking process is followed by a printing process for printing the printing
paper with the plates mounted on the first and second plate cylinders
11
and
12. The printing process is carried out as follows.
First, each dampening water feeder
21a,
21b,
21c,
21d and each ink feeder
20a,
20b,
20c,
20d are placed in contact with only a corresponding one of the plates
mounted on the first and second plate cylinders
11 and
12. Consequently,
dampening water and inks are fed to the plates from the corresponding water feeders
21a,
21b,
21c,
21d and
ink feeders
20a,
20b,
20c,
20d,
respectively. The inks fed to the plates are transferred to the first and second
blanket cylinders
13 and
14, respectively.
Then, the printing paper is fed to the paper feed cylinder
16. The printing
paper is subsequently passed from the paper feed cylinder
16 to the impression
cylinder
15. The impression cylinder
15 continues to rotate in this
state. Since the impression cylinder
15 has half the diameter of the first
and second plate cylinders
11 and
12 and the first and second blanket
cylinders
13 and
14, the black and cyan inks are transferred to the
printing paper wrapped around the impression cylinder
15 in its first rotation,
and the magenta and yellow inks in its second rotation.
The forward end of the printing paper printed in the four colors is passed from
the impression cylinder
15 to the paper discharge cylinder
17. This
printing paper is transported by the pair of chains
19 to the paper discharge
station
28 to be discharged therein.
Upon completion of the printing process, the plates used in the printing are
discharged to the plate discharger
29. Then, the first and second blanket
cylinders
13 and
14 are cleaned by a blanket cleaning unit, not shown,
to complete the printing process.
In such a printing machine as described above, where the recording heads of the
image recorders
25 and
26 are arranged close to the first and second
plate cylinders
11 and
12 at a printing time, mists and particles
of the inks, water, paper and so on floating in the printing machine tend to adhere
to the recording heads. In this printing machine, therefore, the recording head
moving mechanism moves each recording head to a retreat position at a printing time.
The construction of the image recorders
25 and
26 will be described
hereinafter. FIG. 2 is a perspective view showing a principal portion of the image
recorder
25 in the printing machine according to a first embodiment of this invention.
The image recorder
26 has the same construction as the image recorder
25, and will not particularly be described.
The image recorder
25 includes a recording head
201 and a recording
head moving mechanism
202. The recording head moving mechanism
202
has a support member
204 extending between a pair of side plates
209
rotatably supporting the first plate cylinder
11 through bearings
230,
a pair of guide rails
208 fixed to a side surface of the support member
204, and a ball screw
207 extending parallel to the guide rails
208.
The pair of guide rails
208 and the ball screw
207 are parallel to
an axis
231 of the first plate cylinder
11. The ball screw
207
is connected through a speed reducer
205 to a motor
206 fixed an
end of the support member
204. The ball screw
207 is meshed with
a nut
211 attached to a support plate
210 supporting the recording
head
201. Thus, the motor
206 is operable to rotate the ball screw
207, thereby to move the recording head
201 parallel to the axis
231 of the first plate cylinder
11.
In time of recording an image, this recording head moving mechanism
202
moves the recording head
201 at constant speed through a moving region
220
between a recording start position A shown in solid lines in FIG. 2 and a recording
finish positions B shown in phantom lines to record the image on the printing plate
mounted peripherally of the plate cylinder
11. After recording the image,
the recording head
201 is moved to a retreat position
221 shown in
phantom lines C in FIG. 2, which is displaced sideways from the moving region
220.
The recording head
201 is kept on standby in the retreat position
221
until a next image recording time.
By keeping the recording head
201 on standby in the retreat position
221
at a printing time, the above printing machine minimizes the chance of the recording
head
201 being contaminated by the inks, water, paper particles and so on
dispersed in the printing machine.
Other embodiments of this invention will be described next. FIG. 3 is a perspective
view showing a principal portion of an image recorder
25 in the printing
machine according to a second embodiment of this invention. In the following description,
like reference numerals are used to identify like parts which are the same as in
the first embodiment and will not particularly be described again.
The image recorder
25 in the second embodiment, as does the image recorder
25 in the first embodiment, includes a recording head
201 and a recording
head moving mechanism
202.
The image recorder
25 in the second embodiment further includes a chamber
203 for enclosing the recording head
201 moved to the same retreat
position as in the first embodiment, and defining an opening, not shown, opposed
to the moving region
220 for passage of the recording head
201, a
shielding door
212 for opening and closing the opening
212, and a
door moving mechanism
213 for moving the shielding door
212 between
opening and closing positions. The chamber
203 is disposed on an extension
of the direction of movement of the recording head
201, and laterally outwardly
of one side plate
209.
The door moving mechanism
213 includes a pair of guide rails
217
attached to the side plate
209 adjacent the chamber
203, a rack
214
fixed to a side surface of the shielding door
212, and a pinion
216
engaged with the rack
214. The pair of guide rails
217 extend perpendicular
to the direction of movement of the recording head
201 and parallel to the
rack
214. The pinion
216 is attached to a rotary shaft of a motor
215. With the door moving mechanism
213 having the above construction,
the pinion
216 is rotatable by the motor
215 to move the rack
214
engaged with the pinion
216, thereby to move the shielding door
212
in directions perpendicular to the direction of movement of the recording head
201.
This printing machine can further reduce the chance of the recording head
201
being contaminated by the inks, water, paper particles and so on dispersed in the
printing machine, with the shielding door
212 closing the opening formed
for passage of the recording head
201 at least when the recording head
201
is in the retreat position
221.
FIG. 4 is a perspective view showing a principal portion of an image recorder
25 in the printing machine according to a third embodiment of this invention.
The image recorder
25 in the third embodiment, as does the image recorder
25 in the second embodiment, includes a recording head
201, a recording
head moving mechanism
202 and a chamber
203.
However, the image recorder
25 in the third embodiment does not include
the shielding door
212 or door moving mechanism
213. The chamber
203 of the image recorder
25 has a gas intake fan
218. The
fan
218 draws air as a gas from outside the printing machine into the chamber
203, and feeds the air from the chamber
203 to the interior of the
printing machine through the opening for the opening for passage of the recording
head
201. Thus, air currents are formed to flow from outside to inside of
the printing machine.
Preferably, the fan
218 draws fresh air from outside the printing
machine through an air duct not shown. The fan
218 need not be driven at
all times, but will serve the purpose if driven at least during a printing operation.
In this printing machine, the air currents from outside to inside of the printing
machine prevent the inks, water, paper particles and so on dispersed in the printing
machine from entering the retreat position
221. This feature can further
reduce the chance of the printing machine being contaminated by the inks, water,
paper particles and so on.
FIG. 5 is a perspective view showing a principal portion of an image recorder
25 in the printing machine according to a fourth embodiment of this invention.
FIG. 6 is a schematic side view showing movement of a recording head
201
of the image recorder
25 in the fourth embodiment.
The image recorder
25 in the fourth embodiment, as does the image recorder
25 in the second embodiment, includes a recording head
201, a recording
head moving mechanism
202 and a chamber
203.
However, the image recorder
25 in the fourth embodiment does not
include the door moving mechanism
213. The recording head
201 has
a shielding door
212 attached to a position thereof opposed to the moving
region
220 when the recording head
201 is in the chamber
203.
Thus, the shielding door
212 is movable with the recording head
201
to close the opening for passage of the recording head
201 when the recording
head
201 is in the chamber
203.
As shown in FIG. 6, the shielding door
212 has shock absorbing elements
240 such as sponges attached to positions thereof opposed to the recording
head
201. Even when the shielding door
212 collides with the side
plate
209 or chamber
203 in closing the passage opening, the impact
of collision is absorbed to avoid damage to the machine.
The above printing machine can close the opening for passage of the recording
head
201, without providing the door moving mechanism
213, when the
recording head
201 in the retreat position
221. This simple construction
effectively reduces the chance of the recording head
201 being contaminated
by the inks, water, paper particles and so on dispersed in the printing machine.
FIG. 7 is a perspective view of a principal portion of an image recorder
25
in the printing machine according to a fifth embodiment of this invention. FIG.
8 is a schematic sectional view showing a chamber interior of the image recorder
25 in the fifth embodiment.
The image recorder
25 in the fifth embodiment, as does the image recorder
25 in the second embodiment, includes a recording head
201, a recording
head moving mechanism
202 and a chamber
203.
However, the image recorder
25 in the fifth embodiment does not include
the door moving mechanism
213. A gas jet nozzle
250 is connected
to an air compressor not shown, to form an air curtain (a flow in the direction
of an arrow shown in FIG. 8) along an opening of the chamber
203 as a barrier
between the retreat position
221 and moving regions
220. The gas
flow delivered from the gas jet nozzle
250 prevents movement of the inks,
water, paper particles and so on between the retreat position
221 and moving
regions
220.
The above printing machine can block flow of the inks, water, paper particles
and so on between the retreat position
221 and moving regions
220,
without providing the door moving mechanism
213. This simple construction
effectively reduces the chance of the recording head
201 in the retreat
position
221 being contaminated by the inks, water, paper particles and
so on dispersed in the printing machine.
In the foregoing embodiments, one of the side plates
209 rotatably supporting
the plate cylinder
11 is used as a shielding plate. Instead, a shielding
plate may be provided separately from the side plate.
This invention may be embodied in other specific forms without departing from
the spirit or essential attributes thereof and, accordingly, reference should be
made to the appended claims, rather than to the foregoing specification, as indicating
the scope of the invention.
This application claims priority benefit under 35 U.S.C. Section 119 of Japanese
Patent Application No. 2002-326208 filed in the Japanese Patent Office on Nov.
11, 2002, and Japanese Patent Application No. 2003-198246 filed in the Japanese
Patent Office on Jul. 17, 2003, entire disclosure of which is incorporated herein
by reference.
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