Information
-
Patent Grant
-
6736065
-
Patent Number
6,736,065
-
Date Filed
Wednesday, February 21, 200123 years ago
-
Date Issued
Tuesday, May 18, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 101 4151
- 101 485
- 101 486
- 101 378
- 101 3821
- 101 383
- 101 384
- 101 385
- 101 389
- 101 477
-
International Classifications
-
Abstract
A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end. Also disclosed are method and apparatus for mounting a flexible printing plate.
Description
FIELD OF THE INVENTION
The present invention relates to a plate-mounting member which is used to mount a plate onto a plate cylinder disposed in a printing apparatus or a plate-making apparatus. The present invention also relates to method and apparatus for mounting a printing plate, especially, a digitally made flexible printing plate, onto a plate cylinder of a printing apparatus.
DESCRIPTION OF THE RELATED ART
In a lithographic printing apparatus, generally, a printing plate is wound around and fixed to a plate cylinder and, in this state, printing is executed.
However, a lithographic printing plate (in the present specification, this is referred to as a flexible printing plate), which uses as a support member a member formed of other material than metal inexpensive and easy to handle (for example, a plastic film or paper), has a weak point in dimensional stability. For example, the flexible printing plate can be deformed depending on the way of handling of the flexible printing plate when it is mounted or due to a frictional force between a rubber cylinder and itself during printing, which can degrade the printing dimension as well as the printing position accuracy with respect to paper.
Therefore, use of the flexible printing plate of the above type, conventionally, is limited to a simple printing which prints a relatively small number of printings and does not require the high matching accuracy of the printings; that is, such flexible printing plate has not been employed in a high-quality printing using multiple colors and requiring great delicacy or in a full-dress printing using a large-scale printing machine.
Here, description will be given in detail of the above-mentioned deformation that is caused depending on the way of handling of the flexible printing plate when it is mounted. In
FIGS. 19 and 20
, there is shown a typical printing plate-mounting apparatus. Specifically,
FIG. 20
is a view of the printing plate-mounting apparatus when it is viewed from the direction of the arrow mark X shown in
FIG. 19
; and,
FIG. 19
is a section view taken along the line Y—Y shown in FIG.
20
.
As shown in
FIG. 19
, the plate cylinder
61
of the printing machine is structured such that a portion of a cylinder is cut away along the axial direction of the cylinder and, in a substantially flat surface (which is hereinafter referred to as a flat surface portion
61
a,
which is the cut face of the cutaway portion of the cylinder), there is formed a groove portion
65
. And, within the groove portion
65
, there are disposed a plate front end clamp mechanism
62
for holding the front end or leading end of a printing plate
70
, and a plate rear end clamp mechanism
63
for holding the rear end or trailing end of the printing plate
70
. The clamp mechanisms
62
and
63
respectively include lower teeth
62
b
and
63
b
(the upper surfaces of which are substantially flush with the flat surface portions
61
a
), and upper teeth
62
a
and
63
a
which are rotatably supported by their respective lower teeth and are capable of holding the plate front end or rear end between the upper surfaces of their respective lower teeth and themselves. Further, there is disposed a position adjusting mechanism (not shown) which is capable of adjusting the positions of the plate front end clamp mechanism
62
and plate rear end clamp mechanism
63
in the back-and-forth direction, in the right-and-left direction and in the oblique direction on the bottom surface of the groove portion
65
.
Between the two flat surface portions
61
a
and curved surface portion
61
b
of the plate cylinder
61
, there are formed top portions
61
c
respectively. Although not shown, there is known another type of plate cylinder in which there are formed top portions between the upper surfaces of the lower teeth of the clamp mechanisms, instead of the flat surface portions, and the curved portion of the plate cylinder.
Normally, the portions of the plate cylinder
61
, where the two flat surface portions
61
a
and curved surface portion
61
b
cross each other, are each rounded to thereby provide a curved surface having a radius of 5-30 mm. It should be noted here that, in the present specification, such curved surface portions are also referred to as top portions.
And, as shown in
FIG. 20
, two positioning pins
64
are respectively provided on and projected from the upper surface of the lower tooth
62
b
of the plate front end clamp mechanism; specifically, at two positions of the lower tooth
62
b
upper surface which are spaced from each other in the axial direction of the plate cylinder
61
. At the positions of the upper surface
62
of the plate front end clamp mechanism that correspond to the positioning pins
64
, there are formed notches
66
respectively. Also, in the front end portion
70
a
of the printing plate
70
which is shown by a two-dot chained line in
FIG. 20
; specifically, at the positions of the front end portion
70
a
that correspond to the positioning pins
64
, there are also formed two notches
71
respectively.
Recently, as printings have been turned into small lots and diversified, there has increased the need for a plate (which, in the present specification, is referred to as a flexible plate comprising a support member formed of material which is inexpensive and easy to handle (for example, plastic film, paper) other than metal, and a photosensitive layer disposed on such support member. However, since such plate is high in flexibility, there arise several problems when it is mounted on the plate cylinder.
For example, there is generally known a case where the flexible printing plate
70
is mounted onto the plate cylinder
61
using the printing plate-mounting apparatus shown in
FIGS. 7 and 8
. Specifically, in this case, when, while holding the plate rear end
70
b,
an operator pushes the plate front end
70
a
of the printing plate between the upper tooth
62
a
and lower tooth
62
b
of the plate front end clamp mechanism to thereby bring the plate front end
70
a
into contact with two positioning pins
64
, there is a fear that the plate front end
70
a
can be deformed and can be fixed in such deformed state. That is, in a plate cylinder capable of mounting thereon a printing plate of a half-kiku size or more, the distance between the two positioning pins
64
in the plate cylinder
61
is fairly wide; and, therefore, when mounting the printing plate
70
onto the plate cylinder
61
, in case where the operator overpushes the printing plate
70
even slightly, the printing plate
70
can be deformed in such a manner that the plate front end
70
a
is projected in the pushing direction from between the two positioning pins
64
. However, in case where the operator pushes the printing plate
70
insufficiently in order to avoid such deformation of the printing plate
70
, the printing plate
70
cannot be positioned accurately.
As described above, the mountability of the flexible plate onto the plate cylinder is poor and thus it is difficult to always mount the flexible plate onto the plate cylinder in a constant state. Therefore, there are necessary a plurality of plate cylinders and thus, in case where the flexible plate is used in a multicolor printing (for example, four-color printing) which requires strict matching between the plate cylinders, mismatching can occur.
Also, as shown in
FIG. 19
, in the vicinity of the top portions
61
c
respectively formed between the flat surface portions
61
a
and curved portion
61
b
of the plate cylinder
61
, the flexible printing plate
70
does not easily stick to the outer peripheral surface of the plate cylinder
61
but the flexible printing plate
70
tends to float up from the outer peripheral surface of the plate cylinder
61
.
In order to prevent such flotation of the printing plate
70
, an operator, while pulling strongly the plate rear end of the printing plate
70
with the plate front end thereof held by the plate front end clamp mechanism
62
, rotates the plate cylinder to thereby wind the printing plate
70
onto the plate cylinder. In this case, however, the strongly pulled portion of the plate rear end of the flexible printing plate
70
is stretched loosely.
After the printing plate is wound onto the plate cylinder while pulling the plate rear end in the above-mentioned manner, the plate rear end of the printing plate is pushed into between the upper and lower teeth of the plate rear end clamp mechanism, the upper tooth is rotated to thereby fix the plate rear end, and, using a tension apply mechanism (not shown), the plate rear end clamp mechanism is moved in a direction where a tensile force is applied to the printing plate, thereby bringing the printing plate into close contact with the peripheral surface of the plate cylinder, which completes the mounting of the printing plate onto the plate cylinder.
However, in an ordinary conventional plate-mounting apparatus, the tension apply mechanism for contacting the flexible printing plate with the peripheral surface of the plate cylinder closely is designed in combination with a printing plate having a support member formed of metal such as aluminum; and, therefore, in the case of the flexible printing plate, it is stretched more than necessary.
Also, in case where the tension apply mechanism is designed such that it can apply a lower tensile force according to the flexible printing plate, the tensile force applied is too weak to closely contact the printing plate with the plate cylinder. Even if the printing plate can be mounted onto the plate cylinder in such a manner that the printing plate is prevented from floating up from the plate cylinder, in the case of such weak tensile force, the printing plate deviates in position due to a frictional force which is produced between a rubber cylinder and itself in printing.
Recently, in a lithographic printing method, due to the enhancement in the latest digital picture drawing technology as well as due to the need for enhancement in the efficiency of processing, there have been proposed a large number of systems for drawing digital image information directly on a printing plate. This is a technology which is referred to as CTP (Computer-to-plate) or DDPP (Digital Direct Printing Plate).
This technology is advantageous over a conventional plate making method (which provides close-contact exposure with a lith film superimposed on top of a printing plate) in that it can provide better image position accuracy with respect to a flexible printing plate and better matching accuracy in a multicolor printing.
Of course, there is also proposed a digital reprographic (plate making) system using a flexible printing plate; and, because it is inexpensive, there exists the need for a multicolor printing using this system. However, since the flexible printing plate has the above-mentioned problems, it cannot make the best use of its advantage that it can provide excellent image position accuracy in the digital reprography; and, therefore, in a multicolor printing, it has not been able to realize matching accuracy equivalent to that of the printing plate having a metal support member.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the above-mentioned drawbacks.
Accordingly, an object of the invention is to provide a flexible plate-mounting member which is capable of mounting a flexible plate onto a plate cylinder positively and easily.
Another object of the invention to provide flexible printing plate-mounting method and apparatus which is capable of mounting a digitally-made flexible printing plate easily without deforming the same, allows the flexible printing plate to be applied to a conventional printing machine with slight improvements, and allows the flexible printing plate to provide dimensional stability equivalent to that of a metal support member printing plate as well as matching accuracy in a multicolor printing.
Other objects and effects of the present invention will become apparent from the following description.
In a first aspect, the present invention relates to the following items (1-1) to (1-3).
(1-1) A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end.
(1-2) The plate-mounting member according to item (1-1) above, wherein said plurality of fixing pins are disposed on said base along the width direction of said plate and the distance between adjacent fixing pins is not more than 400 mm.
(1-3) The plate-mounting member according to item (1-1) or (1-2) above, wherein deformation preventive notches are formed in the portions of said base that are to be held by said upper and lower teeth.
In a second aspect, the present invention relates to the following items (2-1) to (2-13).
(2-1) A flexible printing plate-mounting method for mounting a flexible printing plate having three or more notches formed in a plate front end thereof onto a plate cylinder, comprising the steps of:
providing a flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and at least three positioning pins respectively disposed in said plate front end clamp mechanism in such a manner that they are respectively opposed to said notches of said printing plate;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate;
positioning and fixing said plate front end to said plate cylinder by inserting the plate front end of said printing plate into between said upper and lower teeth of said plate front end clamp mechanism to contact the inner peripheral surfaces of said notches of said plate front end with said at least three positioning pins;
winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and
pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;
whereby stretching of said flexible printing plate in its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.
(2-2) A flexible printing plate-mounting method for mounting a flexible printing plate having at least three fixing holes formed in a plate front end thereof onto a plate cylinder, comprising the steps of:
providing a flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; positioning pins disposed in said plate front end clamp mechanism; and a pin contact member which has higher rigidity than said printing plate, is to be attached to said positioning pin and has at least three fixing pins for fixing said printing plate;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate;
positioning and fixing said plate front end to said plate cylinder by allowing said fixing holes of said printing plate to be inserted with said fixing pins of said pin contact member between said upper and lower teeth of said plate front end clamp mechanism;
winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and
pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;
whereby stretching of said flexible printing plate in its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.
(2-3) A flexible printing plate-mounting method for mounting a flexible printing plate having at least three fixing holes formed in a plate front end thereof onto a plate cylinder, comprising the steps of:
providing a flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and a positioning pin disposed in said plate front end clamp mechanism;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder;
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate; and
a pin contact member which has higher rigidity than said printing plate and includes at least three fixing pins for fixing said printing plate;
fixing said printing plate on said pin contact member by allowing said fixing holes of said printing plate to be inserted into said fixing pins of said pin contact members respectively;
fixing and positioning said printing plate onto said plate cylinder by fixing a leading end of said pin contact member to said positioning pin between said upper and lower teeth of said plate front end clamp mechanism;
winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and
pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;
whereby stretching of said flexible printing plate in, its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.
(2-4) The flexible printing plate-mounting method according to any one of items (2-1) to (2-3) above, wherein said packing sheet has at least one roughened surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said roughened surface side becomes an outer surface side.
(2-5) The flexible printing plate-mounting method according to any one of items (2-1) to (2-3) above, wherein said packing sheet has at least one sticky surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said sticky surface side becomes an outer surface side.
(2-6) The flexible printing plate-mounting method according to any one of items (2-1) to (2-5) above, wherein said flexible printing plate-mounting apparatus further comprises a guide member for holding said printing plate, wherein said guide member holds said printing plate, before and during mounting said printing plate onto said plate cylinder, in such a manner that the plate rear end thereof is set free.
(2-7) A flexible printing plate-mounting apparatus for mounting a flexible printing plate having three or more notches formed in a plate front end thereof onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and at least three positioning pins respectively disposed in said plate front end clamp mechanism in such a manner that they are respectively opposed to said notches of said printing plate;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate.
(2-8) A flexible printing plate-mounting apparatus for mounting a flexible printing plate onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; positioning pins disposed in said plate front end clamp mechanism; and a pin contact member which has higher rigidity than said printing plate, is to be attached to said positioning pin and has at least three fixing pins for fixing said printing plate;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate.
(2-9) A flexible printing plate-mounting apparatus for mounting a flexible printing plate onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:
a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and a positioning pin disposed in said plate front end clamp mechanism;
a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;
a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder;
a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate; and
a pin contact member which has higher rigidity than said printing plate and includes at least three fixing pins for fixing said printing plate.
(2-10) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-9) above, wherein said packing sheet has at least one roughened surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said roughened surface side becomes an outer surface side.
(2-11) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-9) above, wherein said packing sheet has at least one sticky surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said sticky surface side becomes an outer surface side.
(2-12) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-11), further comprising a guide member for holding said printing plate, before and during mounting said printing plate onto said plate cylinder, in such a manner that the plate rear end thereof is set free.
(2-13) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-12), further comprising:
a rotating member for rotating said plate cylinder when mounting said printing plate onto said plate cylinder;
a detector for detecting the rotational position of said plate cylinder;
a rotation controller for controlling the rotation and stopping of said plate cylinder rotating member at given positions in accordance with signals from said rotational position detector;
a driving member for driving said pressure member so as to be into contact with or separated from said plate cylinder; and
a controller for controlling said driving member at given positions in accordance with signals from said rotational position detector.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a schematic view of embodiment 2-1 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 2
is a view taken from the direction of the arrow mark X shown in
FIG. 1
;
FIG. 3
is a view of a plate base material wound around a plate cylinder according to embodiment 2-1;
FIG. 4
is a view of a hold roller employed in embodiment 2-1;
FIG. 5
shows how to mount a flexible printing plate according to embodiment 2-1;
FIG. 6
also shows how to mount a flexible printing plate according to embodiment 2-1;
FIG. 7
also shows how to mount a flexible printing plate according to embodiment 2-1;
FIG. 8
also shows how to mount a flexible printing plate according to embodiment 2-1;
FIG. 9
is a view of a flexible printing plate and a pin contact member employed in embodiment 2-2 of the flexible printing plate-mounting apparatus according to the invention;
FIGS.
10
(A) and
10
(B) is a view of the flexible printing plate and pin contact member shown in
FIG. 9
, showing a state in which the pin contact member is fixed to the flexible printing plate;
FIG. 11
is a view of a flexible printing plate and a pin contact member employed in embodiment 2-3 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 12
is a view of the flexible printing plate and pin contact member shown in
FIG. 11
, showing a state in which the pin contact member is fixed to the flexible printing plate;
FIG. 13
is a view of embodiment 2-4 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 14
is a view of embodiment 2-5 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 15
is a partially enlarged view of a plate cylinder used in embodiment 2-6 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 16
is a section view taken along the line Y—Y shown in
FIG. 15
;
FIG. 17
is a partially enlarged view of a plate cylinder used in embodiment 2-7 of the flexible printing plate-mounting apparatus according to the invention;
FIG. 18
is a section view taken along the line Y—Y shown in
FIG. 17
;
FIG. 19
is a view of a conventional flexible printing plate-mounting apparatus; and,
FIG. 20
is a view taken from the direction of the arrow mark X shown in FIG.
19
.
FIG. 21
is a plan view of embodiment 1-1 of the plate-mounting member according to the invention;
FIG. 22
is an enlarged view of the main portions of embodiment 1-1 shown in
FIG. 21
;
FIG. 23
is a section view taken along the line III—III shown in
FIG. 22
;
FIG. 24
is a plan view of embodiment 1-2 of the plate-mounting member according to the invention;
FIG. 25
is an enlarged view of the main portions of embodiment 1-2 shown in
FIG. 24
;
FIG. 26
is a plan view of embodiment 1-3 of the plate-mounting member according to the invention;
DETAILED DESCRIPTION OF THE INVENTION
The first aspect of the present invention is described in more detail below.
As the flexible plate, there can be used a support member which is formed of a plastic film or paper other than metal, and a support member which is a combination of such plastic film and paper support members. In more detail, there can be used a support member comprising a plastic film which is formed of polyester, polyethylene terephthalate, polyethylene naphthalate, or polycarbonate; and, a support member comprising a composite sheet which can be produced in such a manner that a plastic sheet formed of polyethylene or polypropylene is laminated on paper. Although it is suitable that the thickness of the support member is set in the range of 75-500 μm, the optimum value of the support member thickness varies according to the kinds of the support members used and printing conditions. Generally, most preferably, the thickness of the support member may be set in the range of 100-400 μm.
The positioning pin disposed in the plate front end clamp mechanism includes a pin which is provided on and projected from the upper surface of the lower tooth of the plate front end clamp mechanism toward the upper tooth thereof, a pin which is provided on and projected from the lower surface of the upper tooth of the plate front end clamp mechanism toward the lower tooth thereof, and a pin which is provided on and projected from the plate cylinder and is arranged in the vicinity of the plate front end clamp mechanism.
The material of the base of the plate-mounting member, preferably, may be higher in rigidity than the flexible plate; for example, metal can be used. The fixing pin may be a pin which is formed integral with the base, or a pin which is produced separately and mounted onto the base afterward.
By using the above-structured plate-mounting member, the front end of the flexible plate can be protected by the plate-mounting member to thereby eliminate the possibility that the plate front end can be projected from between the two positioning pins. Therefore, the mountability of the flexible plate onto the plate cylinder can be enhanced remarkably. This not only can reduce the burden of the operator but also can prevent the above-mentioned mismatching to thereby allow the flexible plate to be used in a multicolor printing as well.
Also, in the above structure, in case where the plurality of fixing pins are disposed on the base of the plate-mounting member along the width direction of the plate and the distance between the fixing pins is equal to or less than 400 mm, the plate can be prevented from being deformed in such a manner that the plate front end is projected from between the two positioning pins. More preferably, in case where the distance between the fixing pins is equal to or less than 270 mm, the plate can be prevented against deformation more positively. The distance between the fixing pins may not be constant, provided it exists in the above-mentioned range.
Also, in case where deformation preventive notches are respectively formed at the positions of the base which are held by the upper and lower teeth, the durability of the plate-mounting member can be enhanced.
Now, description will be given below in detail of preferred embodiments of the plate-mounting member according to the first aspect of the invention with reference to the accompanying drawings. The parts that have been previously described herein are given the same designations or corresponding designations in the drawings and thus the description thereof is simplified or omitted here.
In
FIG. 21
, there are shown a plate-mounting member
30
which provides embodiment 1-1 according to the invention, and a polyester-made printing plate
80
used as a flexible plate onto which the plate-mounting member
30
is to be mounted.
In the plate front end
80
a
of the printing plate
80
, more specifically, at the two portions of the plate front end
80
a
that respectively correspond to the two positioning pins
64
shown in
FIG. 20
, there are formed two notches
81
each having a substantially U-shaped peripheral edge. Also, in the plate front end
80
a,
there are opened up a plurality of (in this embodiment, 7) fixing holes
82
which are spaced from one another by a given distance W
1
in the width direction of the printing plate
80
(the direction along the axial direction of the plate cylinder; in
FIG. 21
, in the right and left direction). The fixing holes
82
can be formed at the same time when the notches
81
are formed.
The plate-mounting member
30
is made of steel, stainless steel, other alloy steel, or brass. The plate-mounting member
30
includes a band-shaped (a rectangular-shaped) base
31
having a length equal to or greater than the width of the printing plate
80
. In the portions of the base
31
that respectively correspond to the two positioning pins
64
, there are formed circular-shaped insertion holes
33
. Also, on the base
31
, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins
32
which are spaced from one another by a given distance in the longitudinal direction of the base
31
. The plurality of fixing pins
32
are disposed on a straight line extending along the width direction of the printing plate
80
, that is, along the longitudinal direction of the plate-mounting member
30
. The size of the fixing pin
32
is not limited but, for example, the fixing pin
32
can be set such that it has a diameter of 6 mm and a height of 4 mm or so. The transverse-direction width of the base
31
is also not limited but the width may only be set such that the base
31
can be prevented from touching the top portions of the plate cylinder when it is mounted onto the plate cylinder.
Now,
FIG. 22
shows an enlarged view of the neighboring portion of each notch
81
of the printing plate
80
shown in
FIG. 21
when the plate-mounting member
30
is mounted onto the plate front end
80
a
of the printing plate
80
. As shown in
FIG. 22
, by inserting the fixing pin
32
of the plate-mounting member
30
into the fixing hole
82
of the printing plate
80
, the plate-mounting member
30
can be fixed to the printing plate
80
. Here, the plate-mounting member
30
and printing plate
80
are set such that a portion of the peripheral edge of the circular-shaped insertion hole
33
of the plate-mounting member
30
can be matched to the curved portion of the substantially U-shaped peripheral edge of the notch
81
of the printing plate
80
.
When mounting the printing plate
80
onto the plate cylinder
61
shown in
FIG. 20
, with the insertion holes
33
of the plate-mounting member
30
respectively inserted into their associated positioning pins
64
of the plate front end clamp mechanism
62
, the plate front end
80
a
of the printing plate
80
is fixed to the plate-mounting member
30
.
Now,
FIG. 23
is a section view taken along the line III—III shown in FIG.
22
. As shown by a two-dot chained line in
FIG. 23
, when the positioning pins
64
of the plate cylinder
61
are inserted into the insertion holes of the plate-mounting member
30
, the inner peripheral surface of the notches
81
of the printing plate
80
are contacted with the positioning pins
64
together with the inner peripheral surfaces of the insertion holes
33
of the plate-mounting member
30
.
With use of the above-structured plate-mounting member
30
, the plate front end
80
a
of the printing plate
80
can be protected by the plate-mounting member
30
as well as the printing plate
80
can be prevented from being deformed in such a manner that the plate front end
80
a
thereof is projected from between the two positioning pins
64
. Therefore, not only the mountability of the flexible printing plate
80
onto the plate cylinder can be enhanced remarkably to thereby reduce the burden of the operator, but also the above-mentioned mismatching can be prevented to thereby allow the flexible printing plate
80
to be used in a multicolor printing as well.
Since a conventionally used plate cylinder can be used as it is, the facility cost cannot be expensive.
Now,
FIG. 24
shows a plate-mounting member
40
, which provides embodiment 1-2 according to the invention, and a printing plate
80
. The plate-mounting member
40
includes a base
41
having a length equal to or greater than the width of the printing plate
80
. In the portions of the base
41
that respectively correspond to the two positioning pins
64
of the plate cylinder
61
shown in
FIG. 20
, there are formed two notches
43
each having a substantially U-shaped peripheral edge. Also, on the base
41
, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins
42
in such a manner that they are spaced from one another by a given distance W
2
(in this embodiment, 120 mm) in the longitudinal direction of the base
41
.
Now,
FIG. 25
shows an enlarged view of the neighboring portion of each notch
81
of the printing plate
80
when the plate-mounting member
40
is mounted onto the plate front end
80
a
of the printing plate
80
shown in FIG.
24
. As shown in
FIG. 25
, by inserting the fixing pins
42
of the plate-mounting member
40
into their associated fixing holes
82
of the printing plate
80
, the plate-mounting member
40
can be fixed to the printing plate
80
. Here, the plate-mounting member
40
and printing plate
80
are set such that the peripheral edges of the notches
43
of the plate-mounting member
40
can be matched to the peripheral edges of the notches
81
of the printing plate
80
.
With use of the above-structured plate-mounting member
40
, not only the plate front end
80
a
of the flexible printing plate
80
can be protected by the plate-mounting member
40
but also the printing plate
80
can be prevented from being deformed in such a manner that the plate front end
80
a
thereof is projected from between the two positioning pins
64
.
Also, according to the present plate-mounting member
40
, when the plate front end
80
a
of the printing plate
80
is fixed to the plate front end clamp mechanism after the plate-mounting member
40
is fixed to the plate front end
80
a,
the plate-mounting member
40
can be inserted into between the upper and lower teeth of the plate front end clamp mechanism, which makes it possible to further simplify the positioning operation of the plate front end
80
a.
Now,
FIG. 26
shows a plate-mounting member
50
, which provides embodiment 1-3 according to the invention, and a printing plate
80
. The plate-mounting member
50
includes a base
51
having a length equal to or greater than the width of the printing plate
80
. In the portions of the base
51
that respectively correspond to the two positioning pins
64
of the plate cylinder
61
shown in
FIG. 20
, there are formed circular-shaped insertion holes
53
. Also, on the base
51
, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins
52
in such a manner that they are spaced from one another by a given distance in the longitudinal direction of the base
51
. Further, in the long side of the base
51
which is opposite to the side thereof where the fixing pins
52
are projectingly provided, more specifically, in the portions of such long side that are to be held by the upper and lower teeth of the plate front end clamp mechanism, there are formed a plurality of (in this embodiment, 6) deformation preventive notches
54
at regular intervals. In this embodiment, each of the deformation preventive notches
54
is formed in a trapezoidal shape when it is viewed from above.
In the above-structured plate-mounting member
50
, when the base
51
is held by and between the upper and lower teeth of the plate front end clamp mechanism, even in case where the base
51
is thereby crushed, the deformation preventive notches
54
are appropriately deformed in shape so as to be able to prevent the whole of the plate-mounting member
50
from being deformed. That is, the deformation of the whole of the plate-mounting member
50
can be absorbed by the deformation of the deformation preventive notches
54
. Therefore, the durability of the plate-mounting member
50
can be enhanced.
As has been described in detail heretofore, with use of the plate-mounting member according to the first aspect of the invention, not only the mountability of the flexible plate onto the plate cylinder can be enhanced remarkably to thereby reduce the burden of the operator, but also the above-mentioned mismatching can be prevented to thereby allow the flexible plate to be used in a multicolor printing as well.
Next, the second aspect of the present invention is described in more detail below.
The term “the maximum printing length in the plate cylinder rotation direction during the printing plate-mounting operation” means the maximum length that can be printed on paper; and, in the specification and instruction manual of a printing machine, as such maximum printing length, there is set forth a concrete numeric value. Generally, this length can be regarded as the length of the area of the plate cylinder on the diameter circumference thereof that extends from the neighboring portion of the top portion of the plate front end to the neighboring portion of the top portion of the plate rear end.
As the pressure member, there can be employed a roller-shaped pressure member which can be driven by a driving member so as to be contacted with or separated from the plate cylinder. Also, there may also be used a flat-surface pressure member such as a pad-shaped, brush-shaped, or flat-surface-shaped pressure member, which can be driven by a driving member so as to be contacted with or separated from the plate cylinder.
As the positioning pin, there can be employed a pin which is provided on and projected from the upper surface of the lower tooth of the plate front end clamp mechanism toward the upper tooth of the plate front end clamp mechanism, a pin which is provided on and projected from the lower surface of the upper surface toward the lower tooth, or a pin which is provided integrally with the plate cylinder.
As the plate rear end fixing mechanism, there can be used a plate rear end clamp mechanism which includes an upper tooth and a lower tooth. Also, there can also be employed a plate rear end hold mechanism using a plate-spring-shaped member, or means for attaching the plate rear end to the plate cylinder surface or a plate rear end clamp member using a double adhesive tape or spray glue.
According to the above-described items (2-1) and (2-7) of the invention, since the flexible printing plate is contacted with three or more positioning pins and is thereby positioned, the distance between the positioning pins in the plate cylinder is narrow, which can eliminate the possibility that the printing plate can be deformed in such a manner that the plate front end can be projected from between the positioning pins. Also, when winding the printing plate onto the plate cylinder, the pressure member presses the printing plate against the entire outer peripheral surface of the plate cylinder including the top portions thereof to thereby bring the printing plate into close contact with the plate cylinder outer peripheral surface. This eliminates the need to wind the printing plate onto the plate cylinder while pulling the plate rear end thereof; that is, a tensile force is not applied to the printing plate positively, so that the printing plate is little stretched. Therefore, even when the stretching of the printing plate due to the resistance of the pressure member in the printing plate-mounting operation is taken into consideration, the stretching of the printing plate in the maximum printing length can be controlled down to 100 μm or less.
Further, since the packing sheet, which is capable of preventing the printing plate from deviating in position after it is wound around and fixed to the plate cylinder, supports the wound printing plate strongly, normally, in case where the tensile force of the printing plate is zero or small, the printing plate can be prevented from deviating in position due to a frictional force produced between the printing plate and rubber cylinder during printing.
Therefore, the dimensional stability of the printing plate in the printing plate-mounting operation as well as in the printing operation can be enhanced remarkably, which makes it possible to obtain multicolor printing matching accuracy equivalent to that of a metal support member printing plate. Further, the mountability of the flexible printing plate onto the plate cylinder can be enhanced greatly, so that the burden of the operator can be relieved.
Needless to say, in the conventional plate-mounting method, it is impossible to realize the subject matter of the present invention that the stretching of the printing plate in the maximum printing length in the plate cylinder rotation direction in the flexible printing plate-mounting operation can be controlled down to 100 μm or less. The first reason for this is that, as described above, when winding the printing plate onto the plate cylinder by rotating the plate cylinder while pulling the plate rear end of the printing plate strongly in order to prevent the printing plate from being floated up from the plate cylinder, the printing plate is easily stretched 100 μm or more. The second reason is that, since the above-mentioned tensile force apply mechanism is designed according to the printing plate using a support member formed of metal such as aluminum, in the case of the flexible printing plate, it is easily stretched 100 μm or more. Also, in case where the tensile force apply mechanism is so designed according to the flexible printing plate as to apply such a low tensile force that can control the stretching of the printing plate down to 100 μm or less, the printing plate cannot be closely contacted with the plate cylinder due to shortage of the tensile force. Even in case where the printing plate can be mounted onto the plate cylinder in such a manner that it is prevented from being floated up from the plate cylinder, with such low tensile force, the printing plate can deviate in position due to a frictional force produced between the rubber cylinder and printing plate in the printing operation.
To control the stretching of the printing plate in the maximum printing length in the plate cylinder rotation direction in the flexible printing plate-mounting operation down to 100 μm or less, in the case of the flexible printing plate, can be attained regardless of the material, size (length, width, thickness) of the flexible printing plate. This is because the flexible printing plate-mounting method according to the invention is a mounting method which does not apply a tensile force to the flexible printing plate positively.
According to the structures employed in the above-described items (2-2), (2-3), (2-8) and (2-9) of the invention, the plate front end of the printing plate can be protected by the high-rigidity pin contact member including at least three fixing pins and thus the deformation of the plate front end can be prevented. Therefore, without increasing the number of positioning pins used, these structures can be relatively easily applied to an existing printing apparatus and an existing plate making apparatus as well. As the material of the pin contact member having higher rigidity than the printing plate, there can be selected metal. However, the material of the pin contact member is not limited to metal specifically.
According to the structures employed in the above-described items (2-4), (2-5), (2-10) and (2-11) of the invention, the plate base material supports the printing plate wound on the plate base material with a high frictional force or a high sticky force. This can eliminate the possibility that the printing plate can deviate in position due to a frictional force produced between the rubber cylinder and printing plate during printing after the printing plate is mounted onto the plate cylinder.
According to the structures employed in the above-described items (2-6) and (2-12) of the invention, by setting the printing plate in the guide member, there can be avoided the possibility that the flexible printing plate can hang down from the plate cylinder due to the low rigidity of the flexible printing plate. This eliminated the need to hold the printing plate by hand, which can in turn simplify the printing plate-mounting operation.
Also, due to the above, there is also eliminated the need to pull the plate rear end strongly, which can contribute effectively toward controlling the stretching of the printing plate.
According to the structure employed in the above-described item (2-13) of the invention, the operator need not execute the rotation and stopping of the plate cylinder as well as the contact and separation of the pressure member with respect to the plate cylinder which have been conventionally necessary when mounting the printing plate onto the plate cylinder. Therefore, not only the burden of the operator can be further relieved but also the flexible printing plate can be mounted onto the plate cylinder quickly.
In JP-A-10-24555 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”), there are disclosed method and apparatus for positioning and fixing the plate front end of a flexible printing plate using three or more reference pins. The fixing method and apparatus employ a mechanism in which three or more reference pins are disposed on the upper surface of an upper tooth thereof and the reference pins are fitted into reference holes formed in a printing plate to thereby position and fix the printing plate. On the other hand, according to the invention, the reference pins are present between the upper and lower teeth of the plate front end clamp mechanism and are used for contact of the printing plate or pin contact member; and, the plate front end is fixed using the plate front end clamp mechanism. Therefore, the fixing method and apparatus disclosed in the above-cited publication are different from the invention in the structure of the apparatus as well as in the function of the reference pins. Also, in the above-cited publication, there is not disclosed the technological idea of the invention that the flexible printing plate is wound onto the plate cylinder while it is pressed against the entire outer peripheral surface of the plate cylinder using the pressure member.
Also, in the registered Japanese utility model publication 3014242, there is disclosed a flexible printing plate-mounting apparatus including a plate hold roller which is used to press a flexible printing plate against a plate cylinder. However, in this publication, there is not disclosed the technological idea of the invention that, in order to prevent the deformation of the plate front end of the flexible printing plate, the plate front end is contacted with three or more positioning pins, or, the plate front end of the printing plate is fixed to the pin contact member having higher rigidity than the printing plate and the pin contact member is then contacted with the positioning pins.
A plate rear end clamp mechanism employed in the printing plate-mounting apparatus disclosed in the above-cited registered utility model publication is structured such that it firstly holds the printing plate and, after then, it pulls the printing plate. That is, in this plate rear end clamp mechanism, there is not disclosed the technological idea of the invention that a tensile force is not applied to the printing plate positively.
Now, description will be given below in detail of preferred embodiments of the second aspect according to the invention with reference to the accompanying drawings. The parts thereof, which have been already discussed herein with reference to the conventional methods and apparatus, are given the same or corresponding designations and thus the description thereof is simplified or omitted here.
FIG. 1
shows embodiment 2-1 of the flexible printing plate-mounting apparatus according to the invention. Specifically,
FIG. 1
shows a flexible printing plate-mounting apparatus
10
which is used to mount a flexible (polyester-made) printing plate
70
onto a plate cylinder
11
provided in a printing apparatus for a multicolor printing (four-color printing).
FIG. 2
is a view of the apparatus
10
taken from the direction of the arrow mark X shown in
FIG. 1
, showing the plate cylinder
11
according to the present embodiment.
As shown in
FIG. 1
, the flexible printing plate-mounting apparatus
10
comprises a plate cylinder
11
including a plate front end clamp mechanism
12
and a plate rear end clamp mechanism
13
; a hold roller
17
and a rubber cylinder
25
which can be respectively contacted with and separated from the outer peripheral surface of the plate cylinder
11
; and, guide member
20
which is used to guide the plate front end of the flexible printing plate
70
to the plate front end clamp mechanism
12
. Here, the plate cylinder
11
can be rotated and stopped by a rotation controller (not shown). Also, the controller includes a member of detecting the rotational position of the plate cylinder
11
.
The guide member
20
is structured by disposing a guide roller
23
on the leading end of each of an appropriate number (in the illustrated embodiment, 2) of support members
22
respectively provided on and projected from a plate-shaped member
21
. Here, as the plate-shaped member
21
, there is used a cover which covers the side surface of a printing apparatus
500
.
The rubber cylinder
25
is structured such that it can be contacted with and separated from the plate cylinder
11
and thus, when winding the printing plate
70
onto the plate cylinder
11
, the printing plate
70
can also be held and pressed by and between the plate cylinder
11
and this rubber cylinder
25
. On the contact portion between the plate cylinder
11
and rubber cylinder
25
, specifically, on the side (in
FIG. 1
, on the left side) of such contact portion where the printing plate
70
can be inserted, there is disposed a hand cover
26
having a substantially L-shaped section; and, the hand cover
26
can prevent an operator from having his or her finger caught in error by and between the rubber cylinder
25
and plate cylinder
11
.
On the plate cylinder
11
, as shown in
FIG. 3
, there is wound and fixed a plate base material
27
(a material forming the base part of the plate cylinder
11
) at least one surface of which is formed as a roughened surface in such a manner that the roughened surface becomes an outer surface side thereof. As a sheet-shaped base material used as the plate base material
27
, there can be employed plastics such as polyethylene terephthalate, polypropylene and polyethylene; or, metal such as aluminum and SUS; or, paper or synthetic paper; or, cloth. That is, any material can be used, provided that it can be well fitted with the plate cylinder
11
of the printing apparatus.
The hold roller
17
, as shown in
FIG. 4
, is assembled to an appropriate driving member such as a cylinder
18
and is structured such that it can be contacted with or separated from the outer peripheral surface of the plate cylinder
11
by a driving member controller (not shown). Here, in order not to damage the flexible printing plate
70
, the hold roller
17
may be preferably formed of elastic material such as rubber.
And, as shown in
FIG. 2
, on the upper surface of the lower tooth
12
b
of the plate front end clamp mechanism
12
, there are projectingly provided three or more (in this embodiment, 7) positioning pins
14
in such a manner that they are spaced by a given distance from one another in the axial direction of the plate cylinder
11
. Here, of the seven positioning pins
14
, only one positioning pin
14
shown on the right in
FIG. 2
has a circular section, whereas the other remaining positioning pins
14
are respectively so formed as to have such a section shape that can be obtained by cutting away the two sides of a circle in a direction to cross at right angles to the axial direction of the plate cylinder
11
, in order that the widths of these positioning pins
14
in the axial direction of the plate cylinder
11
are narrower than the width of the positioning pin
14
having the above-mentioned circular section shape in the axial direction of the plate cylinder
11
.
Also, not only in the appropriate portions of the upper tooth
12
a
that respectively correspond to the positions of the positioning pins
14
, but also in the appropriate portions of the plate front end
70
a
of the printing plate
70
, there are formed notches
16
,
71
, respectively.
When mounting the printing plate
70
onto the thus-structured plate cylinder
11
, the operator firstly sets the printing plate
70
on the guide member
20
, pushes the printing plate
70
in such a manner that the plate front end
70
a
is inserted into between the upper tooth
12
a
and lower tooth
12
b
of the plate front end clamp mechanism
12
, and brings the inner peripheral surfaces of the notches
71
of the plate front end
70
a
into contact with the positioning pins
14
shown in
FIG. 2
to thereby position the plate front end
70
a.
In this state, the upper tooth
12
a
is closed to thereby fix the plate front end
70
a.
Next, in the state shown in
FIG. 1
, the plate cylinder
11
is rotated counterclockwise using the rotation controller (not shown) to thereby wind the printing plate
70
onto the plate cylinder
11
, including curved surface portion
11
b.
During the rotational movement of the plate cylinder
11
, at the time when the controller detects the rotational position of the plate cylinder
11
where the hold roller
17
can be contacted with the flat surface portion
11
a
of the plate cylinder
11
, the controller stops the rotational movement of the plate cylinder
11
.
And, as shown in
FIG. 5
, the hold roller
17
is contacted with the flat surface portion
11
a
of the plate cylinder
11
and the printing plate
70
is pressed against the outer peripheral surface of the plate cylinder
11
. Then, the plate cylinder
11
is rotated again counterclockwise using the rotation controller (not shown). In this manner, the hold roller
17
can be so operated as to press the printing plate
70
against the outer peripheral surface of the plate cylinder
11
before and behind the top portions
11
c
of the plate cylinder
11
. At the then time, the hold roller
17
, which is energized by the cylinder
18
toward the outer peripheral surface of the plate cylinder
11
, is allowed to advance and retreat according to the shape of the outer peripheral surface of the plate cylinder
11
.
The plate cylinder
11
is rotated on and, as shown in
FIG. 6
, at the time when the printing plate
70
is wound on the plate cylinder
11
up to the neighboring portion of the plate rear end clamp mechanism
13
, the rotation controller (not shown) stops the rotational movement of the plate cylinder
11
.
At the then time, the operator, as shown in
FIG. 7
, curves the neighboring portion of the plate rear end of the printing plate
70
to thereby insert the plate rear end
70
b
into between the upper tooth
13
a
and lower tooth
13
b
of the plate rear end clamp mechanism
13
. In this state, the plate rear end
70
b
is floated up from the flat surface portion
11
a
of the plate cylinder
11
and the upper surface of the lower tooth
13
b.
And, the plate cylinder
11
is rotated counterclockwise again using the rotation controller (not shown). In this manner, the hold roller
17
can be so operated as to press the printing plate
70
against the outer peripheral surface of the plate cylinder
11
before and behind the top portions
11
c
of the plate cylinder
11
; and, at the same time, as shown in
FIG. 8
, the plate rear end can be closely contacted with the flat surface portion
11
a
of the plate cylinder
11
and the upper surface of the lower tooth
13
b.
Finally, after the upper tooth
13
a
of the plate rear end clamp mechanism
13
is closed to thereby fix the plate rear end, the hold roller
17
is retreated from the printing plate
70
using the rotation controller (not shown), thereby completing the mounting operation of the flexible printing plate onto the plate cylinder
11
.
In the above-structured flexible printing plate-mounting apparatus
10
, the plate front end
70
a
of the flexible printing plate
70
is contacted with the seven positioning pins
14
which are respectively provided on and projected from the lower tooth
12
b
of the plate front end clamp mechanism, thereby positioning the plate front end
70
a.
Therefore, the distance between the positioning pins
14
in the plate cylinder is narrow when compared with the distance provided in the conventional printing plate-mounting apparatus; and thus, even in the case of a printing plate of a large size such as a half-kiku size, there is eliminated a fear that the flexible printing plate
70
can be deformed in such a manner that the plate front end
70
a
is projected from between the positioning pins
14
.
And, in the flexible printing plate-mounting apparatus
10
, since the hold roller
17
presses the flexible printing plate
70
against the top portions (the top portion on the plate front end clamp mechanism
12
side and the top portion on the plate rear end clamp mechanism
13
side)
11
c
of the outer peripheral surface of the plate cylinder
11
including the portions before and behind the top portions of the outer peripheral surface of the plate cylinder
11
, there is no fear that the flexible printing plate
70
wound around the plate cylinder
11
can be floated up from the outer peripheral surface of the plate cylinder
11
. Therefore, there is no need for the operator to pull the plate rear end
70
b
strongly, which can prevent the plate rear end
70
b
against deformation such as stretch. Also, the burden of the operator in the flexible printing plate-mounting operation can be relieved.
In the present embodiment, when fixing the plate rear end
70
b
to the plate rear end clamp mechanism
13
, the operator curves the neighboring portion of the plate rear end
70
b
of the flexible printing plate
70
to thereby insert the plate rear end
70
b
into between the upper tooth
13
a
and lower tooth
13
b
of the plate rear end clamp mechanism
13
. Thanks to this, the plate rear end clamp mechanism
13
need not be structured such that the upper tooth
13
a
can be opened greatly. That is, the structure of the plate rear end clamp mechanism
13
can be simplified.
Also, since, as the plate-shaped member
21
of the guide member
20
, there is used the cover of the printing apparatus
500
, the flexible printing plate-mounting apparatus
10
can be reduced in cost and size.
And, of the seven positioning pins
14
, the width of only one positioning pin
14
in the axial direction of the plate cylinder
11
is set wider than those of the other remaining positioning pins
14
in the axial direction of the plate cylinder
11
. This makes it possible to contact the inner peripheral surfaces of the notches
71
of the flexible printing plate
70
with the positioning pins
14
easily. Also, the flexible printing plate
70
can be positioned accurately by the positioning pin with the plate-cylinder-axial-direction width thereof set wider than those of the other remaining positioning pins
14
.
Also, the plate cylinder
11
can be automatically rotated by the controller, the rotational movement of the plate cylinder
11
can be stopped at a given position, and the hold roller
17
can also be automatically contacted with and separated from the plate cylinder
11
by the controller. This can relieve the burden of the operator further.
And, on the plate cylinder
11
, there is wound and fixed the plate base material
27
at least one surface of which is formed as a roughened surface in such a manner that the roughened surface becomes an outer surface thereof. Due to this, the deformation and positional deviation of the flexible printing plate
70
after the flexible printing plate
70
is contacted with the outer peripheral surface of the plate cylinder
11
can be prevented positively.
In the present embodiment, when the hold roller
17
is contacted with and separated from the plate cylinder
11
, the rotational movement of the plate cylinder
11
is stopped. However, alternatively, by changing the setting of the controller (not shown), the hold roller
17
may be contacted with and separated from the plate cylinder
11
without stopping the rotational movement of the plate cylinder
11
.
Next, description will be given below of embodiment 2-2 of the flexible printing plate-mounting apparatus according to the invention with reference to
FIGS. 9 and 10
. In the flexible printing plate-mounting apparatus according to embodiment 2-2, as a plate cylinder, there is used a conventional plate cylinder
61
which is shown in
FIGS. 19 and 20
. And, on the present plate cylinder
61
, there is wound and fixed the plate base material
27
(see FIG.
3
), which is used in the previously described embodiment 2-1 and at least one surface of which is formed as a roughened surface, in such a manner that the roughened surface becomes an outer surface thereof.
The flexible printing plate-mounting apparatus according to embodiment 2-2 has a similar structure to the flexible printing plate-mounting apparatus
10
(see
FIG. 1
) according to embodiment 2-1, except for the plate cylinder.
In
FIG. 9
, there are shown a flexible printing plate
80
and a pin contact member
30
to be fixed to the plate front end of the flexible printing plate
80
, which are both used in the present embodiment. In the plate front end of the flexible printing plate
80
, more specifically, in the portions of the flexible printing plate
80
front end that correspond to two positioning pins
64
shown in
FIG. 20
, there are formed two notches
81
each having a substantially U-shaped peripheral edge. Also, in the plate front end, there are formed at least three (in this embodiment, 7) fixing holes
82
at appropriate intervals in the width direction (in
FIG. 9
, in the right and left direction) of the flexible printing plate
80
.
The pin contact member
30
includes a band-shaped base
31
which is formed of high-rigidity material such as metal and has a length equal to or greater than the width of the flexible printing plate
80
. In the base
31
, specifically, in the portions of the base
31
that correspond to the two positioning pins
64
shown in
FIG. 20
, there are formed two circular-shaped insertion holes
33
. Also, the base
31
includes at least three (in this embodiment, 7) fixing pins
32
which are provided on and projected from the base
31
at appropriate intervals in the longitudinal direction of the base
31
.
Now, FIG.
10
(A) is an enlarged view of the neighboring portion of each notch
81
of the flexible printing plate
80
, showing a state thereof when the pin contact member
30
shown in
FIG. 9
is fixed to the plate front end of the flexible printing plate
80
. Also, FIG.
10
(B) is a section view taken along the line Y—Y shown in FIG.
10
(A). As shown in FIG.
10
(A), by inserting the fixing pin
32
of the pin contact member
30
into its associated fixing hole
82
of the flexible printing plate
80
, the pin contact member
30
can be fixed to the flexible printing plate
80
. In this case, the pin contact member
30
and flexible printing plate
80
are set such that a portion of the peripheral edge of the circular-shaped insertion hole
33
of the pin contact member
30
coincides with the curved portion of the substantially U-shaped peripheral edge of the notch
81
of the flexible printing plate
80
.
When mounting the flexible printing plate
80
onto the plate cylinder
61
shown in
FIG. 20
, the plate front end of the flexible printing plate
80
may be firstly fixed to the pin contact member
30
and, after then, the plate front end may be fixed to the plate front end clamp mechanism
62
; or, with the two positioning pins
64
of the plate front end clamp mechanism
62
inserted into the two insertion holes
33
of the pin contact member
30
, the plate front end of the flexible printing plate
80
may be fixed to the pin contact member
30
.
As shown by a one-dot chained line in FIG.
10
(B), when the two positioning pins
64
of the plate cylinder
61
are respectively inserted into the two insertion holes
33
of the pin contact member
30
, the inner peripheral surfaces of the notches
81
of the flexible printing plate
80
are respectively contacted with the two positioning pins
64
together with the inner peripheral surfaces of the two insertion holes
33
of the pin contact member
30
.
The operation to wind and mount the flexible printing plate
80
onto the plate cylinder
61
is executed similarly to embodiment 2-1.
In the above-structured flexible printing plate-mounting apparatus, in case where the plate front end of the flexible printing plate
80
is positioned and fixed by the plate front end clamp mechanism, the present plate front end is protected by the high-rigidity pin contact member
30
, thereby preventing the plate front end against deformation. Therefore, with use of the pin contact member
30
, not only the deformation of the printing plate
80
can be prevented without increasing the number of the positioning pins used, but also it is possible to use the plate cylinder
61
of the existing printing apparatus. In case where the present embodiment is enforced using an existing facility, the facility cost of the present embodiment can be reduced to a great extent.
Next, description will be given below of embodiment 2-3 of the flexible printing plate-mounting apparatus according to the invention with reference to
FIGS. 11 and 12
. In embodiment 2-3, the pin contact member
30
used in the previously described embodiment 2-2 is changed but the remaining portions of embodiment 2-3 are similar in structure to embodiment 2-2.
FIG. 11
shows parts which are used in the present embodiment; that is, a flexible printing plate
80
and a pin contact member
40
to be fixed to the plate front end of the flexible printing plate
80
.
The pin contact member
40
includes a band-shaped base
41
which is formed of high-rigidity material such as metal and has a length equal to or greater than the width of the flexible printing plate
80
. In the base
41
, specifically, in the portions of the base
41
that correspond to the two positioning pins
64
shown in
FIG. 20
, there are formed two circular-shaped insertion holes
43
. Also, the base
41
includes at least three (in this embodiment, 7) fixing pins
42
which are provided on and projected from the base
31
at appropriate intervals in the longitudinal direction of the base
41
.
Now,
FIG. 12
is an enlarged view of the neighboring portion of each notch
81
of the flexible printing plate
80
, showing a state thereof when the pin contact member
40
is fixed to the plate front end of the flexible printing plate
80
. As shown in
FIG. 12
, by inserting the fixing pin
42
of the pin contact member
40
into its associated fixing hole
82
of the flexible printing plate
80
, the pin contact member
40
can be fixed to the flexible printing plate
80
. In this case, the pin contact member
40
and flexible printing plate
80
are set such that a portion of the peripheral edge of the circular-shaped insertion hole
43
of the pin contact member
40
coincides with the curved portion of the substantially U-shaped peripheral edge of the notch
81
of the flexible printing plate
80
.
According to the above-structured flexible printing plate-mounting apparatus, after the pin contact member
40
is fixed to the plate front end of the flexible printing plate
80
, when fixing the present plate front end to the plate front end clamp mechanism, the pin contact member
40
can be inserted into between the upper and lower teeth of the plate front end clamp mechanism to thereby position both of the pin contact member
40
and the plate front end of the flexible printing plate
80
. This makes it possible to simplify the plate front end positioning and fixing operation further.
Next,
FIG. 13
shows embodiment 2-4 of the flexible printing plate-mounting apparatus according to the invention. In the flexible printing plate-mounting apparatus
90
according to embodiment 2-4, the upper tooth
93
a
of a plate rear end clamp mechanism
93
provided in a plate cylinder
91
can be pulled apart greatly from the upper face of the lower tooth
93
b
of the plate rear end clamp mechanism
93
: that is, the upper tooth
93
a
can be held in such a manner that it does not cover the upper surface of the lower tooth
93
b.
In embodiment 2-4, the upper tooth
93
a
can be rotated until an angle formed between the lower surface of the upper tooth
93
a
and the upper surface of the lower surface
93
b
becomes equal to or greater than an angle where the plate rear end and the clamp surface of the upper tooth
93
a
are not contacted with each other in a state shown in FIG.
13
.
In the present embodiment, on the plate cylinder
91
, there is wound and fixed a plate base material at least one surface of which is formed as a sticky surface in such a manner that the sticky surface becomes an outer surface thereof.
The sticky surface can be formed, for example, by spraying a spray adhesive onto a sheet-shaped base body, by bonding two-side adhesive tape to the sheet-shaped base body, or by applying sticky material to the base body.
When mounting the flexible printing plate
70
, using a similar process to embodiment 2-1, the plate front end is fixed by a plate front end clamp mechanism
92
, including an upper tooth
92
a
and a lower tooth
92
b,
and the flexible printing plate
70
is wound around the outer peripheral surface of the plate cylinder
91
. And, as shown in
FIG. 13
, at the time when the flexible printing plate
70
is wound around the plate cylinder
91
up to the neighboring portion of the plate rear end clamp mechanism
93
, the upper tooth
93
a
of the plate rear end clamp mechanism
93
is opened wide to thereby set the upper tooth
93
a
in a state in which it does not cover the upper surface of the lower tooth
93
b.
And, as shown in
FIG. 13
, a hold roller
17
is contacted with the curved surface portion of the plate cylinder
91
to thereby press the flexible printing plate
70
against the outer peripheral surface of the plate cylinder
91
and, in this state, the plate cylinder
91
is rotated counterclockwise. In this case, due to the operation of the hold roller
17
, the flexible printing plate
70
can be pressed against the outer peripheral surface of the plate cylinder
91
before and behind the top portions
91
c
of the plate cylinder
91
and, at the same time, the plate rear end
70
b
of the flexible printing plate
70
can be closely contacted with the flat surface portion
91
a
of the plate cylinder
91
and the upper surface of the lower tooth
93
b.
Finally, after the upper tooth
93
a
of the plate rear end clamp mechanism is closed to thereby fix the plate rear end
70
b,
the hold roller
17
is retreated from the flexible printing plate
70
, which completes the mounting of the flexible printing plate
70
onto the plate cylinder
91
.
In the above-structured flexible printing plate-mounting apparatus
90
, since there is eliminated the need that the plate rear end
70
b
of the flexible printing plate
70
is curved and is thereby inserted into between the upper tooth
93
a
and lower tooth
93
b
of the plate rear end clamp mechanism
93
, the flexible printing plate-mounting operation can be simplified further and the-thus simplified operation is suitable for automation as well.
Now,
FIG. 14
shows embodiment 2-5 of the flexible printing plate-mounting apparatus according to the invention. In the flexible printing plate-mounting apparatus
100
according to embodiment 2-5, as the pressure member which is used to press a flexible printing plate
70
against the outer peripheral surface of the plate cylinder
91
at least before and behind the top portions of a plate cylinder
101
(including flat surface portions
101
a,
top portions
101
c,
a plate front end clamp mechanism
102
, and a plate rear end clamp mechanism
103
), there is employed a flat surface pressure member. Here, the flat surface pressure member is structured such that a brush
117
, the leading end portions of which are substantially the same in height so as to form a single flat surface, can be driven by an air cylinder
18
to thereby contact the brush
117
with the plate cylinder
101
and separate the brush
117
from the plate cylinder
101
.
As the brush
117
, there can be employed a brush formed of chemical synthetic fiber such as nylon, polypropylene, vinyl chloride, PBT and aramide; a brush formed of plant fiber (palm); or, a brush formed of animal fiber (pig fur, horsehair, sheep fur).
The operation to wind the flexible printing plate
70
onto the plate cylinder
101
is carried out in a similar manner to embodiment 2-1. However, in the present embodiment, since the flexible printing plate
70
can be pressed against the outer peripheral surface of the plate cylinder
101
over a wide range by the flat surface pressure member, in a process for winding the flexible printing plate
70
, the accuracy of the timing for stopping the rotation of the plate cylinder
101
may be set low.
In the above-structured flexible printing plate-mounting apparatus
100
, since the flexible printing plate
70
can be pressed against the outer peripheral surface of the plate cylinder
101
over a wide range by the flat surface pressure member, the floating of the flexible printing plate
70
from the outer peripheral surface of the plate cylinder
101
can be prevented positively and easily. For example, while rotating and stopping the plate cylinder
101
by hand, the flexible printing plate
70
can be mounted onto the plate cylinder
101
.
In the present embodiment, the brush is structured such that the leading end portions thereof can be so arranged to form a flat surface. However, the leading end portions of the brush may also be so arranged as to form a plurality of flat surfaces, provided that the brush can press the flexible printing plate
70
against the outer peripheral surface of the plate cylinder
101
; for example, the leading end portions of the brush may be arranged such that the section of the brush leading end face is formed as a V shape.
Also, in the present embodiment, the flat surface pressure member is structured by using the brush. However, instead of the brush, there can be used a pad which is formed of sponge (urethane sponge, cellulose sponge) or felt. And, it is also possible to use a pad in which core material such as sponge, felt or rubber is covered with molten (cloth).
Next, description will be given below of embodiment 2-6 of the flexible printing plate-mounting apparatus according to the invention with reference to
FIGS. 15 and 16
.
FIG. 15
is a partially enlarged view of a plate cylinder
111
according to the present embodiment. Within a groove portion
115
formed in the plate cylinder
111
, there are disposed a plate front end clamp mechanism
112
(including an upper tooth
112
a
and a lower tooth
112
b
) and a plate rear end clamp mechanism
113
(including an upper tooth
113
a
and a lower tooth
113
b
). In the lower tooth
112
b
of the plate front end clamp mechanism
112
, there are formed notches each having a rectangular shape when it is viewed from above, in such a manner that they are spaced from each other at a given interval in the axial direction of the plate cylinder
111
; and, in each notch, there is disposed a pin block
119
which is formed integral with the plate cylinder
111
. And, a positioning pin
114
is provided on and projected from the pin block
119
, and is accommodated by notch
116
.
As shown in
FIG. 16
which is a section view taken along the line Y—Y shown in
FIG. 15
, one side surface of the pin block
119
is closely contacted with the side surface of the groove portion
115
.
In the above-structured flexible printing plate-mounting apparatus, the positioning pin
114
is formed integral with the plate cylinder
111
through the pin block
119
. Due to this, the plate front end portion can be positioned with more accuracy.
Next, description will be given below of embodiment 2-7 of the flexible printing plate-mounting apparatus according to the invention with reference to
FIGS. 17 and 18
. Here,
FIG. 17
is a partially enlarged view of a plate cylinder
121
according to embodiment 2-7. Within a groove portion
125
formed in the plate cylinder
121
, there are disposed a plate front end clamp mechanism
122
and a plate rear end clamp mechanism
123
. The clamp mechanisms
122
and
123
respectively include plate-shaped upper teeth
122
a
and
123
a.
In the present embodiment, the upper teeth
122
a
and
123
a
are respectively fixed within the groove portion
125
. And, on the lower surface of the upper tooth
122
a
of the plate front end clamp mechanism
122
, there are projectingly provided positioning pins
124
at given intervals in the axial direction of the plate cylinder
121
.
Now,
FIG. 18
is a section view taken along the line Y—Y shown in FIG.
17
. On the upper portion of a lower tooth
122
b
disposed on the bottom surface of the groove portion
125
, there is disposed a shaft-shaped cam member
130
the diameter of which is reduced at the portions that correspond to the positioning pins
124
hanging from the upper tooth
122
a.
And, between the cam member
130
and upper tooth
122
a,
there is interposed a plate spring
131
. By rotating the cam member
130
, the upper tooth
122
a
and plate spring
131
can opened and closed with respect to each other, which makes it possible to hold the plate front end of the flexible printing plate
70
. That is, in the present embodiment, the plate spring
131
substantially functions as a lower tooth for holding the plate front end between the upper tooth
122
a
and itself.
In the above-structured flexible printing plate-mounting apparatus, the positioning pins
124
are disposed on the upper tooth
122
a
in such a manner that they extend toward the lower tooth
122
b;
and thus, the upper tooth
122
a
is not movable. Therefore, a hold roller can be made to approach very closely to the upper tooth
122
a,
so that the flexible printing plate
70
can be closely contacted with the plate cylinder
121
more positively.
As has been described heretofore, according to the mounting method and apparatus of the invention for mounting a flexible printing plate, especially, a digitally-made flexible printing plate, the dimensional stability of the flexible printing plate in the flexible printing plate-mounting operation and printing operation can be enhanced remarkably, thereby being able to obtain multicolor printing matching accuracy equivalent to that of a metal support member printing plate. Also, the mountability of the flexible printing plate onto a plate cylinder can also be enhanced greatly, which makes it possible to reduce the burden of an operator. Further, since the invention can also be enforced simply by improving an existing printing machine to a slight degree, the facility cost of the invention can be saved.
While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
Claims
- 1. A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end,wherein deformation preventative notches are formed in the portions of said base that are to be held by said upper and lower teeth.
- 2. The plate-mounting member according to claim 1, further comprising means for mounting the plate-mounting member to a plate cylinder, wherein said means for mounting is disposed on said base.
- 3. The plate-mounting member according to claim 1, wherein said base and said fixing pins are configured and arranged so that when said base is clamped by said plate front end clamp mechanism, said flexible plate is also clamped by said plate front end clamp mechanism.
- 4. The plate-mounting member according to claim 1, wherein the plate is positioned by notches upon mounting onto the plate cylinder.
- 5. The plate-mounting member according to claim 1, wherein said plurality of fixing pins are disposed on said base along the width direction of said plate and the distance between adjacent fixing pins is not more than 400 mm.
Priority Claims (2)
Number |
Date |
Country |
Kind |
P. 2000-043031 |
Feb 2000 |
JP |
|
P. 2000-070598 |
Mar 2000 |
JP |
|
US Referenced Citations (7)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 950 925 |
Oct 1999 |
EP |
840 745 |
Jul 1960 |
GB |