Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
TITLE OF THE INVENTION
BLANKET WASHING METHOD AND BLANKET WASHING SOLUTION
REMOVING METHOD FOR USE IN WEB OFFSET PRINTING PRESS
BACKGROUND OF THE INVENTION
(1) Field of the invention
The p-resent invention relates to a web offset
printing press, particularly, to a blanket washing
method, and a blanket washing solution removing method
after washing for use in a web offset printing press
of a shaftless type.
(2) Description of Related Art
In a web offset printing press, a pattern is
once transferred from a machine plate of a plate
cylinder onto a blanket mounted on the outer peripheral
surface of a blanket cylinder, then printed on a web
fromtheblanket. Continuousprintingallows residue
of ink to attach to the blanket. When the quantity
of the residual ink increases, this adversely affects
on the printing quality of products . For this, when
a certain number of sheets are printed, the printing
is once stopped, the blanket cylinder is thrown off
to wash the blanket (hereinafter referred as blanket
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wash) . When the plate is changed and the printing is
resumed with a new plate, it is necessary to remove
a pattern of the old plate from the blanket . When the
plate is changed, blanket wash is carried out, as well.
Blanket wash is generally performed by rotating the
blanket cylinder while it is thrown off and supplying
a washing solution to the blanket.
A web offset printing press generally
comprises, as shown in FIG. 17, a feeding unit 2 having
a web roll 1, an infeed unit 3 drawing out a web
(strip-like paper) from the web roll 1, printing units
4 including a plurality of printing units 4a through
4d each having the above plate cylinder, the blanket
cylinder, etc. , a drier unit 5 applying heat onto the
web 10, on which printing has been performed, to dry
it, a cooling unit 6 cooling the heated web 10, a web
pass unit 7, and a folder 8 processing the strip-like
web 10 into signatures, as essential parts.
Heretofore, a web offset printing press of a line-shaft
type (shaft machine) is general, in which driving units
of the infeed unit 3, the printing units 4a through
4d, the cooling unit 6, the web pass unit 7 and the
folder 8, etc. are connected to a main motor 11 through
a common line shaft 12, and the driving units are
integrally driven under a driving control on the main
motor 11 by,.a control unit 15.
In such a shaft machine, the printing units
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4a through 4d are connected to the infeed unit 3 making
the web 10 run and the cooling unit 6 by the line shaft
12, so that the printing units 4a through 4b rotate
at a speed equal to the running speed of the web 10.
When blanket wash is carried out, the web 10 runs at
a speed equal to the peripheral speed of the blanket
cylinder. During which, the web 10 becomes all spoiled,
because no printing is, of course, carried out.
Heretofore, before printing is started, the
printing press is driven at a slow-operating speed
(preferably the minimum speed) to decrease the run
length of the web 10, thereby suppressing generation
of spoilage . When blanket wash is carried out during
printing, the current printing speed is reduced to a
certain extent, and blanket wash is carried out . After
completion of the washing, the speed is again increased
to the printing speed, and the printing is resumed.
Whereby, the run length of the web 10 during the blanket
wash is decreased, thereby suppressing generation of
spoilage.
Recently developed was a web offset printing
press (shaftless machine) of a shaftless type
(separately driving type) without a conventional line
shaft, in which, as shown in FIG. 18, drive motors 24a
through 24d, 2,3, 26, 27 and 28 are provided to respective
driving units such as printing units 4a through 4d,
an infeed unit 3, a cooling unit 6, a web pass unit
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7, a folder 8, etc. In this shaftless machine, control
units 34a through 34d, 33, 36, 37 and 38 are provided
correspondingly to the respective drive motors 24a
through 24d, 23, 26, 27 and 28. The drive motors 24a
through 24d~ 23, 26, 27 and 28 are electrically
synchronized and operated under synchronous controls
of the control units 34a through 34d, 33, 36, 37 and
38.
Also developed was a web offset printing press
of another type, in which only printing units 4a through
4d are connected by a line shaft 22 and integrally driven
by a drive motor 24 through the line shaft 22, and drive
motors 23, 26, 27 and 28 are respectively provided to
another driving units such as an infeed unit 3, a cooling .
unit 6, a web pass unit 7, a folder 8, etc., as shown
in FIG. 19. In a web offset press of this type, control
units 33, 34, 36, 37 and 38 are provided correspondingly
to the respective drive motors 23, 24, 26, 27 and 28,
and the drive motors 23, 24, 26, 27 arid 28 are
electrically synchronized and operated under
synchronous controls of the control units 33, 34, 36,
37 and 38. Since web offset printing presses of this
type are basically of a shaftless type although having
a line shaft in part, the web offset printing presses
show in FIGS . 18 and 19 will be generally referred as
shaftless machines, hereinafter. Blanket wash can be
carried out in the known manner as above in these
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shaftless machines, as a matter of course. Actually,
blanket wash is carried out in the shaftless machines
just as done in shaft machines.
However, it is necessary in the known manner
5 to decrease the peripheral speed of the blanket
cylinder synchronized with the running speed of the
web 10, that is, the washing speed during the blanket
wash, in order to decrease the run length of the web
10. This causes degradation of the effect of washing,
or causes a longer washing time, resulting in an
increase in run length of the web 10, and an increase
in amount of spoilage. For this, there are
requirements for more effective blanket wash, and for
improvement in the productivity by decreasing the
amount of spoilage generated at the time of blanket
wash as much. as possible. Particularly, shaftless
machines have characteristics that the printing units
can.be driven independently of other driving units,
so that it is desired to solve the above problems while
making the best use of the characteristics of the
shaftless machines.
A gap is generally formed in the blanket
cylinder to catch a blanket therein, whereby the
blanketiswoundaroundtheblanketcylinder. However,
the washing solution enters in the gap at the time of
blanket wash. The washing solution in the gap flies
out by centrifugal force according to the peripheral
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speed of the blanket cylinder. When the operation is
resumed, the web is contaminated by the washing
solution flying out from the gap of the blanket cylinder
for a while after the web has reached the printing speed.
Printed matter printed during this has a high
probabilitythatcontaminationbythewashingsolution
is attached thereon, thus being generally treated as
spoilage from the viewpoint of the printing quality.
This is also a common problem among the known shaft
machines and shaftless machines . There is thus a
demand to decrease the amount of spoilage caused by
the washing solution after the blanket wash to improve
the productivity.
SUMMARY OF THE INVENTION
In the light of the above problems, an object
of the present invention is to provide a blanket washing
method for use in a web offset printing press, by which
a blanket can be efficiently washed, and the amount
of spoilage generated when the blanket is washed can
~be decreased.
Another obj ect of the present invention is to
provide a blanket washing solution removing method for
use in a web offset printing press, by which a washing
solution having entered in a gap of a blanket cylinder
can be efficiently removed, and the amount of spoilage
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generated after printing has been resumed can be
decreased.
. In order to accomplish the fo-rmer obj ect, the
present invention provides a blanket washing method
on the condition that a web offset printing press which
can control separately the running peed of a web and
the rotation speed of a printing unit is used therein.
In a blanket washing method according to this
invention, a blanket cylinder of a printing unit is
thrown off, and a blanket mounted on a surface of the
blanket cylinder is washed while the blanket cylinder
is operated at a peripheral speed differing from the
running speed of the web. In order to decrease the
amount of generated spoilage, it is essential that the
peripheral speed of the blanket cylinder is increased
to improve the washing efficiency to shorten the
washing time, and the running speed of the web is
decreased to shorten the run length of the web. By
washing the blanket while the blanket cylinder is
operated,at a peripheral speed differing from the
running speed of the web as above, it becomes possible
to set the peripheral speed of the blanket cylinder
and the running speed of the web to speeds suited to
provide efficient washing and to decrease the amount
of generated spoilage.
Preferably, the blanket is washed while the
blanket cylinder is rotated at a peripheral speed
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higher than the running speed of the web. Heretofore,
the peripheral speed of the blanket cylinder is equal
to the running speed of the web, so that the run length
of the web becomes longer when the peripheral speed
of the blanket cylinder is increased to shorten the
washing time, or the washing time of the blanket becomes
longer when the run length of the web is shorten by
decreasing the running speed of the web. In either
case, it is difficult to decrease the amount of spoilage.
By rotating the blanket cylinder at a peripheral speed
higher than the running speed of the web as above, it
is possible to shorten the washing time without
increasing the run length of the web, or shorten the
run length of the web without increasing the washing
time of the blanket, and decrease the amount of spoilage
compared with the former.
When the above washing method is applied to
washing of the blanket at the time of a start of printing,
the following method is preferable . During a course
of increasing the running speed of the web from a
stopping state to a predetermined stand-by speed or
after the running speed has been increased, the blanket
cylinder is thrown off, the blanket is washed while
the blanket cylinder is rotated at a predetermined
washing speed higher than the stand-by speed,. the
peripheral speed of the blanket cylinder is reduced
to the stand-by speed after the blanket has been washed,
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the blanket cylinder is thrown on, and the running speed
of the web is increased to a predetermined printing
speed . By carrying out the washing in the above method,
it is possible to improve the washing efficiency of
the blanket to shorted the washing time, and decrease
the amount of spoilage generated when the washing is
carried out at the time of a start of printing_
Preferably, the above stand-by speed is set to a
slow-operating speed, more preferably, to a minimum
running speed of the web.
When the above washing method is applied to
washing of the blanket cylinder during printing, the
following method is preferred. During a course of
reducing the running speed of the web from a
predetermined printing speed to a predetermined
stand-by speed, the blanket cylinder is thrown off,
the blanket is washed while the blanket cylinder is
rotated at a predetermined washing speed higher than
the stand-by speed, the peripheral speed of the blanket
cylinder is synchronized with the running speed of the
web after the blanket has been washed, the blanket
cylinder.is thrown on, and the running speed of the
web is again increased to the printing speed.
Alternatively, the running speed of the web is
increased while the peripheral speed of the blanket
cylinder is synchronized with the running speed of the
web after washing has been completed, and the blanket
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cylinder is thrown on when the speeds are synchronized,
or at the printing speed. By carrying out the washing
in the above method, it is possible to feed the web
at a low speed to shorted the run length thereof during
5 the washing while the blanket cylinder is rotated at
a high peripheral speed, thereby keeping the washing
efficiency at a high level; and decrease the amount
of spoilage generated when the washing is carried out
during printing.
10 When the blanket is washed before printing is
started or during printing, the blanket is washed in
the above method. After the blanket has been washed,
it is preferable to add a step of rotating the blanket
cylinder at a peripheral speed higher than a peripheral
speed at the time of washing before the blanket cylinder
is thrown on to remove a washing solution attached to
the blanket. By rotating the blanket cylinder at a
peripheral speed higher than the peripheral speed at
the time of washing, it is possible to remove a washing
solution having entered in a gap of the blanket cylinder
by centrifugal force, thereby decreasing the amount
of spoilage generated after the printing is resumed.
Whereby, the above former and latter objects can be
accomplished.
When the above washing method is applied to
washing of the blanket cylinder after completion of
printing; thefollowing methodispreferable. During
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a course of reducing the running speed of the web from
a predetermined printing speed to a stopping state,
the blanket cylinder is thrown off, the blanket is
washed while the blanket cylinder is rotated at a
predetermined washing speed, andtheperipheral speed
of the blanket cylinder is reduced to the stopping state
after the blanket has been washed. By carrying out
the-washing in the above method, it is possible to rotate
the blanket cylinder at a high peripheral speed while
the speed of the web is reduced, thereby keeping the
washing efficiency at a high level; and decreasing the
amount of spoilage generated when the washing is
carried out after completion of printing.
In this case, preferably, the running speed
of the web is reduced to a predetermined stand-by speed
(a slow-operating speed, preferably, a minimum running
speed) after the blanket cylinder has been thrown off,
and the running speed of the web is reduced.to a stopping
state after the blanket has been washed. By slowing
operating the web without stopping the web during the
blanket.washing, it is possible to prevent the washing
solution from attaching to the same portion of the web,
and prevent the web from breaking.-
The blanket washing method according to this
invention can provide a larger effect by providing a
pair of guide means disposed on an upper stream side
and a lower stream side, of the blanket cylinder in the
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running path of the web to change the course of the
running path of the web. A running path of the web
is changed by the guide means to reduce or get rid of
a contact of the web with the blanket cylinder when
the blanket cylinder is thrown off and the blanket is
washed while the blanket cylinder is rotated at a
peripheral speed differing from the running speed of
the web. When the guide means is provided as above,
there is less possibility of paper breaking when the
blanket is washed, so that feeding of the web may be
stopped.
Depending on the type of the web offset printing
press, it is possible to giving a tension to the web
to clamp the same, and wash the blanket while the blanket
cylinder idles with respect to the web.
The present invention also provides a web
offset printing press and a control program for
realizing the above blanket cylinder washing method.
According to the present invention, a web offset
printing press being able to separately control a
running speed of a web and a rotation speed of. a printing
unit comprises a control unit for automatically
operating a whole of the printing press to wash a blanket
of the printing unit in the above blanket washing method.
A control program (first control program) according
to the present invention is a program executable in
a computer for controlling a web offset printing press,
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which can separately control a running speed of a web
and a rotation speed of a printing unit . The control
program is executed in the computer for controlling
to automatically operate a whole of the printing press
to wash a blanket in the above blanket washing method.
In order to accomplish the latter obj ect, the
present invention provides a blanket washing solution
removing method on condition that a web offset printing
press which can separately control a running speed of
a web and a rotation speed of a printing unit is used
therein.
A blanket washing solution removing method of
the present invention comprises the steps of operating
a blanket cylinder at a peripheral speed differing from
the running speed of the web with the blanket cylinder
thrown off after a blanket mounted on a surface of the
blanket cylinder of the printing unit has been washed
to remove a washing solution attached to the blanket .
The blanket cylinder is rotated to remove a washing
solution attached to the blanket cylinder
(particularly, in a gap) by centrifugal force. By
rotating the blanket cylinder independently of feeding
of the web, it is possible to set the peripheral speed
of the blanket cylinder to a speed suitable to remove
the washing solution, and decrease the amount of
generated spoilage.
Preferably, the blanket cylinder is rotated
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at a peripheral speed higher than the running speed
of the web to remove the washing solution attached to
the blanket. Since the washing solution flies out from
the gap according to the peripheral speed, the blanket
cylinder is rotated at a peripheral speed higher than
the running speed of the web to remove,the washing
solution. Even when the blanket cylinder is thrown
on, the washing solution does not fly out from the gap
so long as the running speed of the web does not exceed
the peripheral speed of the blanket cylinder, so that
contamination of the web by the washing solution, that
is, generation of spoilage, can be prevented. More
preferably, the blanket cylinder is rotated at a
peripheral speed higher than a maximum peripheral speed
at the time of printing to remove the washing solution
attached to the blanket cylinder. Whereby, the
washing solution does not fly out from the gap during
printing, and contamination of the web by the washing
solution, that is, generation of spoilage, can be
prevented highly probably.
In this case, it is preferable that the web
is slowly fed at a predetermined stand-by speed. By
slowly operating the web without stopping the same,
it is possible to prevent the washing solution from
attaching to the same portion of the web, and the web
from breaking. When printing is started or when
printing is resumed, a drier temperature increasing
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process of increasing a temperature of a drier unit
while the web is fed at a predetermined stand-by speed
is performed. Preferably, a process of removing the
washing solution attached to the blanket is performed
5 in parallel to the drier temperature increasing process .
By carrying out the process of removing the washing
solution in parallel to the drier temperature
increasing process, it is possible to shorten the
preparation time before printing is started, and
10 decrease the amount of spoilage generated during the
preparation time.
The blanket washing solution removing method
of the present invention can provide a larger effect
by providing a pair of guide means on an upper stream
15 side and a lower stream side of the blanket cylinder
in the running path of the web to.change the course
of the running path of the web. When the blanket
cylinder is thrown off, and the blanket cylinder is
operated at a peripheral speed differing from the
running speed of the web to remove the washing solution
attached to the blanket, the guide means are operated
to reduce or get rid of a contact of the web with the
blanket cylinder. When the guide means are provided,
there is less possibility of paper breaking when the
washing solution is removed, so that the feeding of
the web may be stopped.
Depending on the type of the web offset printing
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press, it is possible to give a tension to the web to
make the blanket cylinder idle with respect to the web,
thereby removing the washing solution attached to the
blanket.
The present invention still further provides
a web offset printing press and a control program for
realizing the above blanket washing solution removing
method. A web offset printing press (a second web
offset printing press) according to the present
invention, which can separately control a running speed
of a web and a rotation speed of a printing unit,
comprises a control unit for automatically operating
a whole of the printing press to remove a washing
solution attached to a blanket in the above blanket
washing solution removing method. A control program
(a second control.program) according to the present
invention is a control program executable in a computer
for controlling a web offset printing press, which can
separately control a running speed of a web and a
rotation speed of a printing unit . The control program
is executed in a computer for controlling to'
automatically operate a whole of the printing press
to remove a washing solution attached to a blanket in
the above blanket washing solution removing method.
A web offset printing press of a so-called
shaftless type ( separately driving type) , for example,
corresponds to the web offset printing press being able
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to separately control the running speed of the web and
the rotation speed of the printing unit, to which the
blanket washing method or the blanket washing solution
removing method according to the present invention are
applied. Even a web offset printing press of a line
shaft type, it corresponds to the above web offset
printing press so long as a mechanical coupling of the
printing units with a relating unit group such as the
infeed unit, the cooling unit, the web pass unit, folder,
etc. can be released, and the printing units can be
separately driven. The present invention can be
applied to even a web offset printing press of a line
shaft type in which the mechanical coupling among the
units cannot be released so long as it has a variable
speed gear between the line shaft and each unit, or
a clamping means-for clamping the web, with the web
tensioned, although there is limitation on the
employable blanket washing method or blanket washing
solution removing method.
20-
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a time chart showing an operation
pattern of a web offset printing press according to
a first embodiment of this invention;
FIG. 2 is a time chart showing an operation
pattern of the web offset printing press according to
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1s
the first embodiment of this invention;
FIG. 3 is a time chart showing an operation
pattern of the web offset printing press according to
a second embodiment of this invention;
FIG. 4 is a time chart showing an operation
pattern of the web offset printing press according to
the second embodiment of this invention;
FIG. 5 is a time chart showing a modification
of the operation pattern of the web offset printing
press according, to the second embodiment of this
invention;
FIG. 6 is a time chart showing an operation
pattern of the web offset printing press according to
the second embodiment of this invention;
FIG. 7 is a time chart showing a modification
of the operation pattern of the web offset printing
press according to a third embodiment of this
invention;
FIG. 8 is a time chart of an operation pattern
of the web offset printing press according to the third
embodiment of this invention;
FIG. 9 is a time chart showing a modification
of the operation pattern of the web offset printing
press according to the third embodiment of this
invention;
FIG. 10 is a time chart showing a modification
of the operation pattern of the web offset printing
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press according to the third embodiment of this
invention;
FIG. 11 is a time chart showing a modification
of the operation pattern of the web offset printing
press according to the third embodiment of this
invention;
FIG. 12 is a schematic side view of a printing
unit of a web offset printing press according to a fourth
embodiment of this invention, with essential parts
thereof enlarged;
FIG. 13 is a partial plan view of a printing
unit in the direction of an arrow VI in FIG. 12, with
a web and a blanket automatic washing unit omitted;
FIGS . 14 (a) and 14 (b) are time charts showing
modifications of the operation pattern in FIG. 1;
FIGS. 15 (a) and 15 (b) are time charts showing
modifications of the operation pattern in FIG. 2;
FIG. 16 is a time chart showing a modification
of the operation pattern in FIG. 4;
FIG. 17 is a schematic diagram showing a
structure of a known web offset printing press of a
line shaft type;
FIG. 18 is a schematic diagram showing a
structure of a known web offset printing press of a
shaftless type; and
FIG. 19 is a schematic diagram showing a
structure of a known web offset printing press of a
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shaftless type.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
5 Hereinafter, description will be made of
embodiments of the present invention with reference
to the drawings.
(A) First Embodiment
First, description will be made of a first
10 embodiment of this invention with reference to FIGS .
1 and 2. Here, the present invention is applied to
a conventional commercial web offset printing press
of a shaftless type (hereinafter referred as a
shaft less ma chine) , and the structure of this shaftless
15 machine is as shown in FIG. 18.
FIGS. 1 and 2 are time charts showing operation
patterns of the shaftless machine used in blanket
cylinder washing methods according to the first
embodiment, wherein the rotation speed of the printing
20 units 4a through 4d and the running .speed of the web
10 are changed with time. In these drawings, the
running speed of the web 10 is denoted by a solid line,
whereas the rotation speed of the printing units 4a
through 4d (equal to the peripheral speed of the blanket
cylinder) is converted to a running speed, and denoted
by a broken line. Overlapped portion of the solid line
and the broken line is denoted by only the solid line .
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According to the first embodiment, the blanket is
washed when the printing is started.
When receiving an operation start command, the
control units 34a through 34d, 33, 36, 37 and 38 give
commands to the respective drive motors 24a through
24d, 23; 26, 27 and 28 to drive the driving units, that
is, the printing units 4a through 4d, the infeed unit
3, the cooling unit 6, the web pass unit 7 and the folder
8. As shown in FIG. 1, the running speed of the web
10 is raised from a stopping state to a predetermined
stand-by speed Vo. The stand-by speed Vo is a
slow-operating speed, which is preferably set to the
minimum running speed of the web 10.
When the running speed of the web 10 reaches
the stand-by speed Vo, the rotation speed of the
printing units 4a through 4d is increased to a
predetermined washing speed V1 with the running speed
of the web 10 kept at the stand-by speed Vo . The washing
solution is supplied, and blanket wash is carried out
for a predetermined time while the rotation speed of
the printing units 4a through 4d is kept at the washing
speed V1. Any washing speed higher than at least the
stand-by speed Vo suffices. The washing time is
determined according to the washing speed V1, so that
the higher the washing speed V1, the shorter the washing
time is.
After completion of the blanket wash, the
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rotation speed of the printing units 4a through 4d is
decreased to the stand-by speed Vo, which is the running
speed of the web 10 . The rotation speed of the printing
units 4a through 4d is synchronized with the running
speed of the web 10, and the blanket cylinder is thrown
on. After register adjustment, color adjustment,
etc. , the running speed of the web 10 is increased to
a predetermined printing speed, and printing is carried
out.
It is possible to improve an effect of washing
the blanket and shorten the washing time by washing
the blanket in the above method, as compared with the
conventional method in which blanket wash is carried
out while the printing units 4a through 4d are rotated
at the same speed as the running speed of the web. As
a result, it is possible to shorten the run length of
the web 10 and decrease the amount of spoilage generated
during the blanket wash.
When the washing solution having enter in the
gap of the blanket cylinder is removed after the blanket
has been washed, the machine is operated in an operation
pattern as shown in FIG. 2 . After completion of blanket
wash, the rotation speed of the printing units 4a
through 4d is further increased from the washing speed
Vl, as shown in FIG. 2. When the rotation speed of
the web 10 reaches a predetermined washing solution
removing speed V2, the rotation speed of the printing
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units 4a through 4d is kept at the washing solution
removing speed V1 for a predetermined time. Any
washing solution removing speed V1 higher than at least
the washing speed V1 suffices. Preferably, the
washing solution removing speed V2 is higher than the
running speed (printing speed) of the web 10 at the
time of printing, more preferably, set to the maximum
rotation speed of the printing units 4a through 4d.
Whereby, the washing solution having entered in the
gap of the blanket cylinder flies out therefrom.
After a predetermined time has elapsed, the
rotation speed of the printing units 4a through 4d is
decreased to the stand-by speed Vo, which is the running
speed of the web 10, the rotation speed of the printing
units 4a through 4d is synchronized with the running
speed of the web 10, and the blanket cylinder is thrown
on, like the case shown in FIG. 1. After register
adjustment, color adjustment, etc., the running speed
of the web 10 is increased to a predetermined printing
speed, and printing is carried out.
It is possible to remove the washing solution
having entered in the gap of the blanket cylinder by
centrifugal force by rotating the blanket cylinder at
a peripheral speed higher than the peripheral speed
at the time of washing after completion of blanket wash.
Even if the washing solution remains in the gap of the
blanket cylinder, there is little possibility that the
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washing solution flies out from the gap so long as the
peripheral speed of the blanket cylinder does not
exceed the above washing solution removing speed.
Accordingly, it is possible to decrease the amount of
spoilage caused by the washing solution after printing
is resumed.
Meanwhile, the above operation pattern can be
realized in the following controlling method, for
example. While the blanket cylinder is in the
thrown-on state and the rotation speed of the printing
units 4a through 4d is matched with the speed of the
web 10, a control on the drive motors 24a through 24d,
23, 26, 27 and 28 by the respective control units 34a
through 34d, 33, 36, 37 and 38 is carried out on the
basis of a virtual master generated with the position
of the axis of the drive motor 28 of the folder 8 as
a reference. In other words, a speed synchronizing
control of synchronizing the rotation speeds with the
virtual master is performed on the drive motors 28,
23, 26 and 27 of the folder 8, the infeed unit 3, the
cooling unit 6 and the web pass unit 7, whereas a speed
synchronizing control of synchronizing the rotation
speeds of and a phase synchronizing control of
synchronizing the phases with the virtual master is
performed on the drive motors 24a through 24d of the
printing units 4a through 4d.
When the blanket cylinder is thrown off and
CA 02510392 2002-09-25
the printing units 4a through 4d are rotated at a
rotation speed differing from the speed of the web 10,
the control units 34a through 34d of the printing units
4a through 4d are disconnected from the virtual master,
5 and the control on the drive motors 24a through 24d
is switched from the phase synchronizing control with
the virtual master from a speed control based on a fixed
target speed. When washing of the blanket and removal
of the washing solution are completed, the control is
10 switched from the speed control to the phase
synchronizing control with the virtual master to bring
the machine into the printable state.
Note that the above controlling method is
merely one example, thus another control may be
15 employed so long as the operations in the patterns shown
in FIGS. 1 and 2 are possible. For example, two kinds
of virtual master for the phase synchronizing control
on the drive motors 24a through 24d of the printing
units 4a through 4d may be generated. The phase
20 synchronizing control with one virtual master may be
performed when the blanket cylinder is thrown on,
whereas the speed synchronizing control or the phase
synchronizing control with the other virtual master
maybe performed when the blanket is washed or the
25 washing solution is removed.
(B) Second Embodiment
Next, description will be made of a second
CA 02510392 2002-09-25
26
embodiment of this invention with reference to FIGS .
3 and 4. A blanket washing method according to the
second embodiment can be applied to a conventional
commercial web offset printing press of a shaftless
type, like the first embodiment, thus description will
be made, re ferring to the printing press shown in FIG.
18 in the second embodiment.
FIGS. 3 and 4 are time charts showing a blanket
washing method according to the second embodiment,
wherein the rotation speed of the printing units 4a
through 4d and the running speed of the web 10 are
changed.with time. The running speed of the web 10
is denoted by-a solid line, whereas the rotation speed
of the printing units 4a through 4d is converted to
a running speed and denoted by a broken line in the
drawings. An overlapped portion of the sold line and
the broken line is shown by only the solid line . In
the second embodiment, the blanket is washed during
printing.
When receiving a blanket washing command
during printing, the control units 34a through 34d,.
33, 36, 37 and 38 give commands to the respective drive
motors 24a through 24d, 23, 26, 27 and 28 to gradually
decrease the running speed of the web 10 from the
printing speed Vlo, as shown in FIG. 3. When the running
speed of the web l0 reaches a predetermined washing
speed (for example, 200 rpm) V11, the blanket cylinder
CA 02510392 2002-09-25
27
is thrown off. The washing speed V11 may be set to
the printing speed Vlo or the washing speed V1 in the
first embodiment, or may be set at a speed higher than
these.
After the blanket cylinder is thrown off, the
washing solution is supplied, and blanket wash is
started while the rotation speed of the printing units
4a through 4d is kept at the washing speed V11. At
the same time, the running speed of the web 10 is further
decreased from the washing speed V11 to a predetermined
stand-by speed V12. Any stand-by speed V12 lower than
at least the washing speed Vll suffices. Preferably,
the stand-by speed V1z is set to the slow-operating
speed, more preferably, to at the minimum running speed
of the web 10. Blanket wash is carried out for a
predetermined time, but the higher the washing speed
V11, the shorter the washing time is.
After completion of the blanket wash, the
running speed of the web 10 is again increased to the
washing speed V11, which is the rotation speed of the
printing units 4a through 4d. The running speed of
the web l0 is synchronized with the rotation speed of
the printing units 4a through 4d, and the blanket
cylinder is thrown on. After the the blanket cylinder
is throw on, the running speed of the web 10 is again
increased to the printing speed Vlo, and printing is
resumed.
CA 02510392 2002-09-25
28
By washing the blanket in the above method,
it becomes possible to drive the web 10 more slowly
and shorten the run length of the web 10 during the
washing, as compared with a case where blanket wash
is carried out while the web 10 is fed at the same speed
as the rotation speed of the printing units 4a through
4e as before. It i.s also possible to increase the
peripheral speed of the blanket cylinder than before,
and keep the washing efficiency at a high level. As
a result, it is possible to decrease the amount of
spoilage generated when washing is carried out during
printing.
When the washing solution having entered in
the gap of the blanket cylinder is removed after the
blanket cylinder has been washed, the machine is
operated in an operation pattern as shown in FIG. 4.
After completion of blanket wash, the rotation speed
of the printing units 4a through 4d is further increased
from the washing speed V11 . When the rotation speed
of the printing units 4a through 4d reaches a
predetermined washing solution removing speed V13, the
rotation speed of the printing units 4a through 4d is
kept at the washing solution removing speed V13 for
a predetermined time. Any washing solution removing
speed V13 higher than at least the washing speed VII
suffices, likethefirst embodiment. Preferably, the
rotation speed of the printing units 4a through 4d is
CA 02510392 2002-09-25
29
higher than the printing speed Vlo. More preferably,
the rotation speed of the printing units 4a through
4d is set at the maximum rotation speed therof . Whereby,
the washing solution having entered in the gap of the
blanket cylinder flies out to the outside.
After a predetermined time has elapsed, the
rotation speed of the printing units 4a through 4d is
decreased to the washing speed V11, whereas the running
speed of the web 10 is increased from the stand-by speed
V12 to the washing speed Vil. The running speed of the
web 10 is synchronized with the rotation speed of the
printing units 4a through 4d, and the blanket cylinder
is thrown on. After that, the speed of the web 10 is
again increased, and printing is resumed:
By rotating the blanket cylinder at a high speed
after completion of blanket wash, it is possible to
remove the washing solution having entered in the gap
of the blanket cylinder by centrifugal force, and
decrease the amount of spoilage caused by the washing
solution after printing is resumed. The above
operation pattern may be realized in a controlling
method similar to that according to the first
embodiment, description of which-is thus omitted.
When the running speed of the web 10 is
decreased from the printing speed Vlo to the stand-by
speed V12, there is set a temporary wait time at the
washing speed V11, as shown in FIGS . 3 and 4 . However,
CA 02510392 2002-09-25
the running speed of the web 10 may be linearly decreased
from the printing speed Vlo to the stand-by speed V12,
as shown in FIG. 5. The blanket cylinder is thrown
off when the running speed of the web 10 reaches the
5 washing speed V11, and blanket wash is started while
the rotation speed of the printing units 4a through
4d is still kept at the washing speed Vli-
(C) Third Embodiment
Next, description will be made of a third
10 embodiment of this invention with reference to FIGS .
6 through 11. A blanket washing method according to
the third embodiment can be applied to a conventional
commercial web offset printing press of a shaftless
type like the first embodiment, description of the
15 third embodiment will be made, referring to the
prin-ting press shown in FIG. 18 like the first
embodiment. Each operation pattern to be described
hereinafter can be realized in a controlling method
similar to that in the first embodiment, practical
20 description of the controlling method is thus omitted
here.
FIG. 6 is a time chart showing the blanket
washing method according to the third embodiment,
wherein the rotation speed of the printing units 4a
25 through 4d and the running speed of the web 10 are
changed with time. The running speed of the web 10
is shown by a solid line, whereas the rotation speed
CA 02510392 2002-09-25
31
of the printing units 4a through 4d is converted to
a running speed, and shown by a broken line in the
drawings . An overlapped portion of the solid line and
the broken line is shown by only the solid line . In
the third embodiment, the blanket is washed after
printing has been completed (after one job has been
finished).
When receiving a printing finish command, the
control units 34a through 34d, 33, 36, 37 and 38 give
commands to the respective drive motors 24a through
24d, 23, 26, 27 and 28 to gradually decrease the running
speed of the web 10 from the printing speed V2o, as
show in FIG. 6. When the running speed of the web 10
reaches a predetermined washing speed (for example,
200 rpm) V21, the blanket cylinder is thrown off . The
washing speed V21 may be set to the same speed as the
washing speed V11 in the second embodiment.
After the blanket cylinder has been thrown off,
the washing solution is supplied and blanket wash is
started while the rotation speed of the printing units
4a through 4d is kept at the washing speed V21. At
the same time, the running speed of the web 10 is further
decreased from the washing speed V21 to a predetermined
stand-by speed Vz2. Any stand-by speed V22 lower than
at least the washing speed Vzl suffices. Preferably,
the stand-by speed V22 is set to the slow operating
speed, more preferably, to the minimum running speed
CA 02510392 2002-09-25
32
of the web 10. Blanket wash is carried out for a
predetermined time, but the higher the washing speed
V21, the shorter the washing time is . After completion
of blanket wash, the rotation speed of the printing
units 4a through 4d is decreased to the stopping state,
and the running speed of the web 10 is also decreased
to the stopping state, in agreement with the decreasing
speed of the printing units 4a through 4d.
By washing in the above method, it is possible
to rotate the blanket cylinder at a high peripheral
speed while the running speed of the web 10 is decreased.
This can keep a high washing efficiency and decrease
the amount of spoilage generated when the washing is
performed after completion of the printing.
Incidentally, it is alternatively possible to
continuously decrease the running speed of the web 10
to the stopping state after the blanket cylinder has
been thrown off, thereby to provide the above effects,
as well. In which case, there is a possibility that
the washing solution intensively attaches to the same
portion of the web 10 because the blanket wash is carried
out while the web 10 is stopped. For this, it is
preferable that the web 10 is not stopped but slowly
operated during the blanket wash, as shown in FIG. 6.
It is thereby possible to prevent the washing solution
from intensively attaching to the same portion of the
web 10, and preventing the web 10 from breaking.
CA 02510392 2002-09-25
33
In FIGS. 6 and 7, a temporary wait time is
provided at the washing speed V21 when the running
speed of the web 10 is decreased from the printing speed
V2o to the stand-by speed V22 or the stopping state .
Alternatively, the running speed of the web 10 may be
linearly decreased from the printing speed VZO to the
stand-by speed VZZ or the stopping state, like the first
embodiment (refer to FIG. 5).
The blanket wash allows the washing solution
to enter in the gap of the blanket cylinder. The
process of removing the washing solution having entered
in the gap is performed after the printing press is
re-started and before the printing is started. In
concrete, the washing solution removing process is
performed in operation patterns as shown in FIGS. 8
through 10. In FIGS. 8 through 10, the running speeds
of the web 10 is shown by a solid line, whereas the
rotation speed of the printing units 4a through 4d is
converted to a running speed and shown by a broken line .
An overlapped portion of the solid line and the broken
line is shown by only the solid line.
FIGS . 8 and 9 show operation patterns applied
when the plate is changed after completion of printing.
After the plate has been change, ink pre-supply (QSI )
of preliminarily supplying ink in quantity according
to the next pattern to the ink roller group is preferably
performed before the printing is started. By
CA 02510392 2002-09-25
34
performing the ink pre-supply in prior, it becomes
possible to shorten a time for color adjustment (a time
required for the adjusting process), and decrease
spoilage generated at the time of adjustment by
shortening the adjusting time.
First, the operation pattern in FIG. 8 will
be described. The blanket cylinder is thrown off, with
the web 10 running at a predetermined stand-by speed
(a slow operating speed, preferably the minimum speed)
V23, and the rotation speed of the printing units 4a
through 4d is increased without rest to the washing
solution removing speed V24. When the rotation speed
of the printing units 4a through 4d reaches a
predetermined washing solution removing speed V24, the
rotation speed is kept at the washing solution removing
speed V24 for a predetermined time. The washing
solution removing speed Vz4 is preferably higher than
the printing speed, more preferably, is set at the
maximum rotation speed of the printing units 4a through
4d. Whereby, the washing solution having entered in
the gap of the blanket cylinder can be removed by
centrifugal force. Accordingly, the amount of
spoilage caused by the washing solution after the
printing is resumed can be decreased.
After a predetermined time has elapsed, the
rotation speed of the printing units 4a through 4d is
decreased to a predetermined ink pre-supplying speed
CA 02510392 2002-09-25
VzS. The above ink pre-supply is performed for a
predetermined time while the rotation speed is kept
at the ink pre-supplying speed V25. After completion
of the ink pre-supply, the rotation speed of the
5 printing units 4a through 4d is decreased and
synchronized with the running speed V23 of the web 10,
the blanket cylinder is thrown on, and the printing
press shifts to the normal operation.
In the operation pattern shown in FIG. 9, a
10 washing solution removing process is carried out at
the washing solution removing speed V24. After that,
the rotation speed of the printing units 4a through
4d is temporarily decreased to the running speed VZs
of the web 10, again increased to the ink pre-supplying
15 speed V25, and the ink pre-supplying process is carried
out. If the controlling method described in the first
embodiment is employed, the drive motors 24a through
24d of the printing units 4a through 4d are controlled
under the speed control at a fixed target speed when
20 the washing solution removing process or the ink
pre-supplying process is carried out. This speed
control is a feed-back control. However, the control
system of the printing presses has some control delay,
so that an actual final rotation speed is deviated a
25 little from a target speed. Additionally, a direction
of the deviation differs between when the rotation
speed reaches a target speed while increasing and when
CA 02510392 2002-09-25
ss
the rotation speed reaches a target speed while
decreasing. For example, in the case of the operation
pattern shown in FIG. 8, when an actual washing solution
removing speed deviates from a target speed toward a
larger value; an actual ink pre-supplying speed
deviates from the target value toward a smaller value .
When a direction of deviation differs at each speed
as above, setting of a target speed is difficult in
consideration of the deviation, thus the optimum
rotation speed cannot be set . In the operation pattern
shown in FIG. 9, the rotation speed is increased and
reaches a target speed in the ink pre-supplying process,
as done in the washing solution removing process.
Whereby, it .is possible to obtain the optimum rotation
speed in each process. Incidentally, this operation
pattern is unnecessary when the control delay is small .
For the purpose of shortening the preparatory time or
decreasing the spoilage, the operation pattern shown
in FIG. 8 is more preferable.
FIG. 10 shows an operation pattern applied when
the printing is resumed without a plate change in the
same job. Since, distribution of quantities of ink on
the ink roller group can remain unchanged when the plate
is not changed, the above ink pre-supplying process
is unnecessary. In this case, the rotation speed of
the printing units 4a through 4d is increased to the
washing solution removing speed V24 to remove the
CA 02510392 2002-09-25
37
washing solution having entered in the gap of the
blanket cylinder. After a predetermined time has
elapsed, the rotation speed of the printing units 4a
through 4d is decreased and synchronized with the
running speed V23 of the web 10, the blanket cylinder
is thrown on, and the printing press is shifted to the
normal operation.
Meanwhile, the drier unit 5 of the web offset
printing press stops its operation when the web 10 is
stoppyed due to completion of printing. When the
printing is resumed, it is necessary to perform a drier
temperature increasing process of again heating the
drier unit S and increasing its temperature, along with
the above washing solution removing process and the
ink pre-supplying process . The web 10 is required to
run at a low speed during the drier temperature
increasing process in order to prevent the web 10 from
being overheated. Since the web 10 and the printing
units 4a through 4d can be separately operated in the
printing press according to this invention, the washing
solution removing process and the ink pre-supplying
process can be carried out in parallel to the drier
temperature increasing process.
FIG. 11 shows an example of an operation pattern
applied when the washing solution removing process
followed by ink preparatory supply is carried out in
paralleltothe drier temperature increasingprocess.
CA 02510392 2002-09-25
38
When the web 10 is stopped, the blanket cylinder is
thrown off, and the running speed of the web 10 is
increased to the stand-by speed V23. On the other hand,
the rotation speed of the printing units 4a through
4d is increased to the washing solution removing speed
Vz4 without rest. Re-heating of the drier unit 5 is
resumed while the running speed of the web 10 is kept
at the stand-by speed V23, and the drier temperature
increasing process is carried out. During this, the
rotation speed of the printing units 4a through 4d is
kept at the washing solution removing speed V24 for
a predetermined time, and the washing solution removing
process is carried out. After the predetermined time
has elapsed, the rotation speed of the printing units
4a through 4d is decreased to the ink pre-supplying
speed V25, and the ink pre-supply is carried out . After
completion of the ink pre-supply, the rotation speed
of the printing units 4a through 4d is synchronized
with the running speed V23 of the web 10, and the blanket
cylinder is thrown on. When the temperature of the
drier unit 5 has been increased, the speeds of the web
10 and the printing units 4a through 4d are started
to be increased. By carrying out the washing solution
removing process and the ink pre-supply in parallel
to the drier temperature increasing process, the setup
time before printing is started can be shortened, and
spoilage generated during the setup time can be
CA 02510392 2002-09-25
39
reduced.
(D) Fourth Embodiment
Next, description will be made of a fourth
embodiment of this invention with reference to FIGS .
12 and 13. A web offset printing press according to
this embodiment has guide units 123 disposed.on the
upstream side of the first printing unit 4a, on the
downstream side of the last printing unit 4d, and at
each intermediate position betweentwoprinting units
4a through 4d, in addition to the structure of the
conventional commercial web offset printing press of
a shaftless-type shown in FIG: 18. In other words,
the guide units 123 are disposed on the upstream side
and the down stream side. of each blanket cylinder in
the running path of the web 10.
As shown in FIGS . 12 and 13, each of the guide
units 123 comprises a bracket 126a or 126b attached
to a frame 125a or 125b, which is positioned on the
both sides of the printing unit, a fulcrum shaft 128a
or 128b rotatably supported by the a bracket 126a, '126b
via a bearing 127a or 127b, an arm 129a or 129b fixed
to the fulcrum shaft 128a or 128b, a pair of guides
124, each of which attached to the arm 129a or 129b,
provided on both the upper side and the lower side of
the web l0, which extend along the direction of the
width of the web 10, a rotary actuator 130 disposed
at the end of the shaft of the fulcrum shaft 128a or
CA 02510392 2002-09-25
128b to swing the guide 124, and a stopper 117
restricting the position of a swinging end of the guide
124. The guide 124 is formed with rollers or bars
(bar-like members ) , which is laid along the transversal
5 direction of the entire unit (the direction along the
width of the web 10). As shown in FIG. 13, the pair
of guides 124 is away from the web 10 when printing
is carried out. By raising or lowering the guides 124,
it is possible to change the running path of the web
10 10. Incidentally, FIG. 13 shows only the left side
of the printing press (on the back side of the paper
of FIG. 12), thus showing only the frame 125a, the
bracket 126a, the bearing 127a, the fulcrum shaft 128a,
and the arm 129a. However, the frame 125b, the bracket
15 126b, the bearing 127b, the fulcrum shaft 127b and the
arm 129b not shown are similarly disposed on the right
side the printing press.
The both ends of each of the guides 124 are
attached to the arms 129a and 129b (both-ends attached
20 structure) . Alternatively, one end of the guide 124
may be attached to the arm 129a or 129b (single-end
attached structure). The rotary actuator 130
functions as a shaft rotating means. The rotary
actuator 130 may have a mechanism formed by combining
25 a link with an air cylinder or a hydraulic cylinder,
other than the above shown. The stopper 117 sets a
positional relationship among the blanket cylinders
CA 02510392 2002-09-25
41
120a and 120b, and the web 10, the position of which
is adjustable. The web guide unit 123 is here a
rotating means, but the web guide unit 123 may be formed
in any one of various methods, or have another structure .
For example, the web guide unit 123 may independently
raise and lower the guide 124 by air cylinders.
In the printing press which prints on both
surfaces of the web 10, the blanket cylinders 120a and
120b of the printing unit 4, which are disposed on the
upper and lower sides of the web path line, are generally
disposed at a predetermined angle 8 to the
perpendicular line as shown in FIG. 12, not
perpendicularly arranged on the both sides of the web.
The reason of this is that the running web 10 is allowed
to contact with the blanket cylinders 120a and 120b
at a predetermined wind angle. Whereby, the web 10
can be conveyed stably and surely, which allows
improvement in printing quality'. An angle 8 between
the blanket cylinders 120a and 120b allows to form a
predetermined gap S between the blanket cylinders 120a
and 120b thrown off.
In the washing operation, the rotary actuators
130 of the guide units 123 are operated to swing the
guides 124, thereby bringing the guides 124 into
contact with the stoppers 117. Whereby, the running
path of the web 10 is changed so as to be positioned
within the gap S . Namely, the running path of the web
CA 02510392 2002-09-25
42
is suitably changed during the washing operation
to decrease the contact of the web 10 with the both
blanket cylinders 120a and 120b, or to guide the web
10 in a tangential direction common to the both blanket
5 cylinders 120a and 120b, thereby allowing the web 10
to pass through between the upper and lower blanket
cylinders 120a and 120b without a contact therewith.
In this embodiment, the blanket washing
process or the blanket washing solution removing
10 process can be performed in similar operation patterns
to those described in the first to third embodiments .
According to this embodiment, the web guide unit 123
is provided. In the washing process or the washing
solution removing process on the blankets 119 provided
on the outer peripheral surfaces of the blanket
cylinders 120a and 120b, the rotary actuators 130 are
driven through the control unit 109 to move the arms
129, so that the arms 129 are shifted to positions
denoted by solid lines in FIG. 12 . The web 10 is thereby
brought into a state where the contact of the web 10
with the blanket cylinders 120a and 120b positioned
above and below the web path line is decreased, or the
web 10 does not contact with the blanket cylinders 120a
and 120b while a predetermined tension is acting
thereon. While the contact of the web 10 with the
blanket cylinders 120a and 120b has been decreased,
or the web 10 is not contact with the blanket cylinders
CA 02510392 2002-09-25
43
120a and 120b, the blankets 119 are washed by automatic
washing units 122, and the washing solution on the
blanket cylinders 120a and 120b is removed at a high
speed.
According to this embodiment, it is possible
to set that the contact of the web 10 passed through
between the blankets 120a and 120b with the same is
decreased, or that the web 10 is not contact with the
blankets 120a and 1.20b, so that the possibility of paper
ripping (breaking of paper) is decreased. Since the
possibility of paper breaking is extremely small, it
is possible to stop convey of the web l0.when the washing
process or the washing solution removing process on
the blankets 119 is performed, which can remarkably
decrease the amount of spoilage.
( F) Others
As having been described the first to fourth
embodiments of this invention, the present invention
is not limited to the above embodiments . The present
invention may be modified in various ways without
departing from the scope of the invention. The
operation patterns shown in FIGS. 1 through 11 are
merely practical examples of the embodiments. With
respect to the blanket washing process, other various
operation patterns are possible so long as the blanket
is washed while the blanket cylinder is rotated
independently of the running of the web, with the
CA 02510392 2002-09-25
44
blanket cylinder thrown off. With respect to the
blanket washing solution removing process, other
various operation patterns are possible so long as the
blanket cylinder is rotated independently of the
running of the web, with the blanket cylinder thrown
off, after the blanket has been washed, thereby
removing the washing solution attached to the blanket .
When the blanket is washed before printing is
started, for example, the rotation speed of the
printing units 4a through 4d is decreased to the
stand-by speed Vo, which is the running speed of the
web 10, to synchronize the speeds after the washing
is completed in the first embodiment, as shown in FIG.
1. Alternatively, the rotation speed of the printing
units 4a through 4dmay be synchronized with the running
speed of the web 10 during the course that the running
speed of the web 10 is increased to the printing speed
V3, as show in FIG. 14(a). Still alternatively, it
is possible that the running speed of the web 10 is
increased to a speed close to the washing speed V1,
the rotation speed of the printing units 4a through
4d is slightly decreased and synchronized with the
running speed of the web 10, after that, the rotation
speed is increased to the printing speed V3, as shown
in FIG. 14(b). If the speed~synchronization after
completion of the washing is performed as above, it
becomes possible to eliminate waste of the deceleration
CA 02510392 2002-09-25
time.
After completion of the washing solution
removing process, it becomes possible that the rotation
speed of the printing units 4a through 4d may be
5 synchronized with the running speed of the web 10, with
the running speed of the web 10 increased to a certain
speed as shown in FIG. 15 (a) , not that the rotation
speed of the printing units 4a through 4d is decreased
to the stand-by speed Vo, which is the running speed
10 of the web 10, and synchronized with the running speed
of the web 10 as shown in FIG. 2. When the washing
solution removing speed VZ is equal to the printing
speed as shown in FIG. 15 (b) , the running speed of the
web 10 may be increased to the printing speed V2, and
15 synchronized with it.
When blanket wash and the washing solution
removing process are both carried out during printing,
the speeds are synchronized at the washing speed Vli
after completion of the washing solution removing
20 process in the second embodiment, as shown in FIG. 4.
Alternatively, the speeds may be synchronized at the
printing speed Vlo, as shown in FIG. 16. If the speeds
are synchronized in the above manner after the washing
solution removing process, it becomes possible to
25 decrease a quantity of deceleration of the printing
units 4a through 4d, and eliminate waste of the
deceleration time.
CA 02510392 2002-09-25
46
In the above embodiments, the present
invention is applied to the known shaftless machine
shown in FIG. 18. However, the shaftless machines is
merely one example to which the present invention can
be applied, thus application of the present invention
is not limited to the printing press having the
structure shown in FIG. 18. For example, the present
invention can be applied to the shaftless machine in
a type shown in FIG. 19. The operation patterns shown
in FIGS. l, 2, 14 (a) , 14 (b) , 15 (a) and 15 (b) , and the
operation patterns shown in FIGS. 8, 9 and 10 can be
also applied to the shaft machine shown in FIG. 17.
In detail, clamping devices (paper holding rollers or
the like) for clamping the web 10 are disposed on the
upper stream side of the front printing unit 4a and
the down stream side of the last printing unit 4d to
fix the web 10, with the web 10 stretched. In this
case, the web 10 is stopped, whereas only the printing
units 4a through 4d idle. Alternatively, variable
speed change gears may be interposed between the line
shaft 12 and the respective printing units 4a through
4d to rotate the printing units 4a through 4d at
different speeds from the running speed of the web 10,
whereby the other operation pattern can be applied.
