JP2002211160A - Block copy sheet for printing lithographic plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a block copy sheet for a lithographic printing plate capable of suppressing a plate deviation without bringing about scumming by preventing a positional deviation of the lithographic printing plate on a plate cylinder of a printer and having excellent manufacturing suitability at a low cost. SOLUTION: The block copy sheet for the lithographic printing plate is interposed between the plate cylinder and the lithographic printing plate made of a material except a metal on at least a rear surface. At least one side surface of the sheet is formed with a protrusion part made of an insular metal foil by laminating a sheet material except the metal and the metal foil having a thickness of 1 to 100 μm and partly removing the metal foil. In this case, an areal occupation rate (AN×100) of the protrusion part, wherein A is a mean area of the protrusion and N is the number per unit area, is 0.1 to 50%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate undersheet for preventing a lithographic printing plate from being displaced on a plate cylinder of a printing press.

[0002]

2. Description of the Related Art Generally, in a lithographic printing press,
The lithographic printing plate is wound around the plate cylinder and mechanically fixed, and printing is performed. Conventionally, as a support for a lithographic printing plate, a support made of a material such as a metal, a plastic film, and paper has been used. A lithographic printing plate using a material other than metal as a support,
Compared with a lithographic printing plate using a metal as a support, it is excellent in handling suitability, but lacks dimensional stability.

In a lithographic printing press, when using a lithographic printing plate having at least a back surface made of a material other than metal as a support, the support is soft and the biting position at the tip of the plate cylinder tends to deteriorate. In that case, the vertical position accuracy (accuracy along the circumferential direction of the plate cylinder) is deteriorated at that time, and in some cases, the plate may be fixed at an angle. Further, for example, there is a problem in that distortion is partially generated due to friction with the plate cylinder during printing, and the positional accuracy with respect to paper is reduced. Therefore, lithographic printing plates with at least the back surface made of a material other than metal are used only for printing a small number of sheets that do not cause a problem even if the registration accuracy of the printed matter is low. When printing a large number of sheets using a printer, color misregistration may occur.

On the other hand, CTP (Computer
The plate making and printing method using plate-to-plate method is more accurate than conventional conventional plate making and printing method (plate material exposure process is based on close contact exposure using lith film). And the advantage is that registration in multicolor printing is easy. However, in the case of a lithographic printing plate having a support made of a material other than metal such as a plastic film or paper as described above, since the above-described problems are caused, registration in CTP multicolor printing is easy. I do not take advantage of that advantage.

Recently, it has been proposed that a sheet material having an initial elastic modulus of 300 kg / mm ² or less be interposed between the printing plate and the printing cylinder in order to solve the above-mentioned problem. JP-A-11-20130). This sheet
Fine glass beads and the like are bonded and fixed so that the center line average roughness Ra is 2 or more. However, as described in the same publication, it can be made by fixing fine glass beads or the like densely and uniformly on the surface of the sheet-like material. In addition, a liquid in which fine particles are dispersed at a high concentration is required.

In general, since fine particles of this kind are expensive, a large amount of fine particles are required to fix them densely and uniformly as described above, which leads to an increase in sheet cost and a high concentration of fine particles. Not only is it difficult to disperse in the liquid, but also in the case of high-concentration dispersion, aggregation tends to occur in the liquid to form coarse particles, which causes a problem that the coarse particles deteriorate the print quality.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reliably prevent a lithographic printing plate from being displaced on a plate cylinder of a printing press, whereby a material other than metal, for example, is used as a support. A lithographic printing plate that can be applied to printing of multiple colors or a large number of sheets, and that not only prevents plate misregistration without causing printing stains but also has excellent cost reduction and manufacturing suitability. To provide a lower sheet. It is a further object of the present invention to provide a lithographic printing plate underlay sheet that can prevent misalignment between the lithographic printing plate and the underlay sheet before printing and does not cause printing stains.

[0008]

Means for Solving the Problems It has been found that the above object of the present invention is achieved by any one of the following constitutions (1) and (2). (1) A lithographic printing underlay sheet interposed between a plate cylinder and a lithographic printing plate having at least a back surface made of a material other than a metal, wherein at least one side of the stencil sheet is 1 μm A metal foil having a thickness of １００100 μm is adhered, and the metal foil is partially removed to form a projecting portion made of an island-shaped metal foil. The average area of the projecting portion is represented by A, the number per unit area thereof. Where N represents the area occupancy of the projections (AN × 100) is 0.1 to 50%.

(2) The underlay sheet for lithographic printing as described in (1) above, wherein the surface of the portion from which the metal foil has been removed is roughened to an average roughness Ra of 1 μm or less.

In the present invention, as described above, an under sheet for a lithographic printing plate material having an island-shaped metal foil convex portion formed on at least one side is used, and the frictional resistance with the lithographic printing plate material is used.
It resists the force applied to the lithographic printing plate material during printing and suppresses distortion (elongation) due to this force. Since the lithographic printing plate underlay material does not suppress the distortion of the lithographic printing plate material by the adhesive force, it is easy to remove the printing plate material, without sacrificing workability, Prevent distortion reliably. Further, the underlay sheet of the present invention, after laminating a sheet material other than metal and a metal foil, the metal foil is partially peeled and removed to form an island-shaped metal foil convex portion, thereby forming the convex portion. Therefore, it is excellent in manufacturing suitability and can achieve cost reduction.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a specific configuration of the present invention will be described in detail. The underlay sheet of the present invention is a sheet-like member having substantially the same area as the lithographic printing plate material, and has the above-described metal foil convex portion on at least one surface thereof.

The substrate used for the underlay sheet may be any substrate having good fit with the plate cylinder of the printing press. For example, polyethylene terephthalate, polypropylene, polyethylene, epoxy resin, xylene resin, aniline resin, acrylic resin, polystyrene , Acrylonitrile,
Examples include various plastics such as polysulfone, polycarbonate, and copolymers thereof, and paper, synthetic paper, and cloth. Preferably, polyethylene terephthalate having excellent dimensional stability and rigidity is preferable. An adhesive material may be provided on a surface of the underplate sheet that is in contact with the plate cylinder of the printing press, the surface being opposite to the surface on which the protrusions are formed.

In the present invention, at least one surface of the sheet material other than the metal of the above-mentioned sheet substrate has a thickness of 1 μm to 100 μm.
m, preferably a metal foil having a thickness of 3 to 30 μm. By setting the thickness in this range, it is possible to effectively obtain the lithographic printing plate distortion suppressing force during printing without causing print smear on the non-image portion. Examples of the material of the metal foil include aluminum, SUS, zinc, iron, copper, and alloys containing them.

As a method for laminating the metal foil, an adhesive may be used between the sheet material to be laminated and, when the sheet material is a thermoplastic resin, the resin is heated to form a solution or a resin. The metal foil may be bonded in a molten state. The rear surface of the metal foil is roughened, and the thermoplastic material (which may be an adhesive) is in a liquid or molten state, and the metal foil can be pressed against a roller to be bonded.

The adhesive or thermoplastic material that can be used in the present invention is not particularly limited. For example, "Adhesion and Adhesives" edited by Masataka Ono, Japan Standards Association (issued in 1989), "Adhesion and Adhesion Society" edited by The Adhesion Society of Japan "Drug Data Book" Nikkan Kogyo Shimbun (published in 1990), Keiji Fukuzawa, "Adhesion Technology" Polymer Publishing Association (published in 1978), Soichi Muroi, "Polymer Latex Adhesive" Polymer Publishing Association (published in 1984) And the like.

Typical examples are vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-
Methacrylate copolymer, methacrylate copolymer, polyvinyl butyral, alkyd resin, epoxy resin, epoxy ester resin, polyester resin, etc. Hydroxyethyl cellulose, casein,
Gelatin, polyacrylate, polyvinylpyrrolidone,
Polyvinyl ether-maleic anhydride copolymer, polyamide, polyacrylamide, vinyl acetate copolymer, acrylate copolymer, isoprene rubber, butadiene rubber,
Chloroprene rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin rubber, nitrobutadiene rubber,
Examples include nitroisoprene rubber, urethane rubber, and fluoro rubber. These resins may be used alone or 2
More than one species may be used in combination.

Further, a crosslinking agent may be used in combination. As the cross-linking agent, any of the known compounds usually used as a cross-linking agent can be used. Specifically, Shinzo Yamashita, Tosuke Kaneko, "Handbook of Cross-Linking Agents", Taiseisha (1981),
Compounds described in “Polymer Data Handbook, Basic Edition” edited by The Society of Polymer Science, Baifukan (1986) can be used. Specifically, ammonium chloride, metal ions, organic peroxides, organic silane compounds, polyisocyanate compounds, polyol compounds, polyamine compounds, titanate coupling compounds, aluminum coupling compounds, polyepoxy groups Examples of the compound include an epoxy resin, a melamine resin, and a poly (meth) acrylate compound.

[0018] In order to further promote the crosslinking reaction, a reaction accelerator may be added as necessary. Examples of the reaction accelerator include organic acids, phenols, organometallic compounds, dithiocarbamic acid compounds, tinouram disulfide compounds, and carboxylic acid anhydrides in the case of a reaction mode in which a crosslinking reaction forms a chemical bond for a functional period. When the crosslinking reaction is of a polymerizable reaction mode, a polymerization initiator (peroxide, azobis-based compound, etc.) may be used.

It is preferable that the thermoplastic resin material is irradiated with light and / or heated after being applied. In order to perform thermosetting, the drying conditions are made stricter than conventional drying conditions. For example, 60 ° C ~
The treatment can be performed at 150 ° C. for 1 to 120 minutes. When a reaction accelerator is used in combination, the treatment can be performed under milder conditions.

The method of partially removing the metal foil after bonding the metal foil is not particularly limited, as long as the metal foil can be partially removed so that the metal foil remains as an island-shaped protrusion. . In particular, a method of forming the projections by eroding the metal foil is preferable in that the shape of the projections can be controlled. Specifically, (i) a method of etching with a laser, (ii) a method of utilizing ablation by an electron beam, (iii) a sandblast method of irradiating hard particles at a high speed by controlling an irradiation position, (iv) a photo A method of forming a projection by applying a resist, pattern-exposing the microprojections, developing the resist, removing the resist, and etching is used. In these methods, since the convex portions are formed based on the resist pattern, the average area and the shape can be arbitrarily adjusted, which is advantageous.

In the present invention, the height of the projection can be easily set by bonding a metal foil having a constant thickness. In addition, by forming the convex portion by eroding the metal foil, it is possible to easily adjust the shape and the occupied area ratio (average area A and number N per unit area) of the convex portion. For example, when using the laser etching method or the sandblasting method, a control device that controls the output pattern by adjusting the scan pattern and laser power of the output laser, and controls the laser irradiation and the sharpened sandblasted irradiation position is also used In the case where a photoresist method is used, the shape and density can be freely set by a contact exposure pattern.

Here, it is easy to understand that the preparation of the shape of the convex portion is performed by controlling the method used in the machining by pattern control. For example, in the method of etching with a laser of (i), a method of cutting a metal with a carbon dioxide gas laser, by controlling the irradiation position and intensity of the carbon dioxide laser light by computer, the area of the convex portion referred to here and The shape can be freely controlled. Similar control is possible in the methods (ii) and (iii). Also in the method (iv), the area and shape of the projections can be arbitrarily controlled by exposing through a baking film on which an arbitrarily processed pattern is formed.

The shape of the metal foil remaining in the shape of an island is not particularly limited, but the major axis is preferably 5 μm or more.
It is preferably from 0 μm to 500 μm. Further, it is preferable that the corners around the formed protrusions be smoothly rounded. This makes it easier to correct the position of the plate. The method of dropping the upper corner of the projection is not particularly limited, and examples thereof include a method of shaking in a liquid in which an abrasive is dispersed, a method of rubbing with a cloth containing an abrasive, and the like.

Further, in the present invention, when the average area of the projections formed of the island-shaped metal foil is A and the number per unit area is N, the area occupation of the projections defined by AN × 100 is obtained. The rate is 0.1 to 50%, preferably 1 to 10%. When the area occupancy of the projections is within the above range, the distortion suppressing force of the lithographic printing plate during printing effectively acts. Here, the average area of the convex portions refers to the average of the area of a plurality of island-shaped metal foils remaining without being removed. Further, the average area A of the projections is preferably 100 mm ² or less, particularly preferably 1 mm ² or less.

In the present invention, it is particularly preferable that the surface of the underlay sheet material other than the metal foil, that is, the surface of the underlay sheet material other than metal is roughened. This allows
It becomes easier to correct the position of the plate. As for the surface roughness, Ra is preferably 1 μm or less. In order to achieve a specific surface roughness, a pre-roughened sheet material may be used, or an underlay sheet material to be used is generally softer than metal, so after applying a metal foil and partially removing it, ,
The sheet material may be roughened. In this case, it is preferable to change the type and / or size of the abrasive, and to change the polishing intensity and polishing time.

The thickness of the underlay sheet of the present invention is preferably from 0.03 mm to 0.6 mm, more preferably from 0.05 mm to 0.6 mm.
0.3 mm. Within this range, handleability in large size, good fit with plate cylinder of printing press,
Further, it is preferable because workability such as tailoring of the printing press is not impaired.

The underlay sheet of the present invention can withstand repeated use. However, depending on conditions, dust and moist water components adhere to the back surface of the plate material and adhere to the island-shaped metal foil, and the dimensional stability of the plate material is reduced. May be reduced. In that case, water,
Alternatively, washing with a petroleum-based solvent (Isopar E) restores the performance and enables repeated use.

A printing machine to which the underlay sheet of the present invention can be applied includes an ink supply device for forming an ink film having a constant thickness on at least the surface of an inking roller, an image portion receiving ink and a non-image non-adhesive portion. A printing drum comprising a printing plate, comprising a printing plate comprising a printing plate, wherein the printing plate is mounted by gripping and fixing a plate head of the printing plate and, if necessary, pulling the plate bottom to urge the printing plate. Any printing press may be used, for example, between a plate cylinder and an impression cylinder of the printing press, an image is transferred by pressing against the plate cylinder, and the image is transferred to a printing material. An offset printing machine to which a blanket cylinder for printing by pressing is added is exemplified.

According to the method of mounting an underlay sheet of the present invention, the underprint sheet is simply sandwiched between the printing plate and the printing plate cylinder so that the convex portion of the island-shaped metal foil faces the back surface of the printing plate. Fix with a mullet vise. Alternatively, at least one end of the underlay sheet is fixed to the plate cylinder together with the printing plate by a mulling vise. Alternatively, the underlay sheet may be fixed to the printing plate cylinder with a spray paste or a pressure-sensitive adhesive to increase the adhesion. In this way, by bringing the island-shaped metal foil protrusions of the underlay sheet into close contact with the backside of the printing plate, it is possible to suppress distortion during printing of the printing plate, for example, distortion of the plate caused by friction between the blanket and the plate during printing. As a result, the print size and accuracy can be maintained.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention. Example 1 20 μm and 130 μm thick hard aluminum foil
It was adhered to a polyethylene terephthalate (PET) film using a nylon-based adhesive of a fusion type. The total thickness was adjusted to 200 μm by changing the thickness of the adhesive and the PET film. A commercially available positive-type photoresist solution is uniformly applied on the hard aluminum surface according to a specified method, and fine dots of 20 μm ² are previously coated on the hard aluminum surface in an area ratio of 0.0.
Two types of lithographic films for contact exposure prepared so as to form 10-step positive dot images from 1 to 75% were brought into close contact with each other and exposed from a high-pressure mercury lamp for a predetermined time. After developing the photoresist with a designated developing solution, the photoresist pattern was used as a mask to uniformly erode the etching solution until the aluminum foil disappeared.

As a lithographic printing plate, a silver salt diffusion transfer photosensitive material using polyethylene terephthalate (PET) having a thickness of 100 μm as a support, and Super Master Plus (total thickness of 130 μm) manufactured by Agfagewald Co., Ltd. were made by a dedicated plate maker SPM415. What was done was used. The lithographic printing plate can also be obtained by a direct drawing printing plate having an image receiving layer on a support other than metal or an electrophotographic plate making using an electrophotographic method.

Next, the obtained underlay sheet and planographic printing plate were cut into a width of 560 mm and a length of 400 mm, respectively, so that the metal surface of the underlay sheet having fine projections was in contact with the back surface of the planographic printing plate. Then, a lithographic printing plate and an underlay sheet were overlaid. The stacked lithographic printing plate and underlay sheet are
Oliver 52 manufactured by Sakurai Co., Ltd. was mounted on a plate cylinder of a single-sided printing machine, and 2,000 sheets were printed under standard printing conditions. Before printing
The surface of the lithographic printing plate was squeezed with a sponge impregnated with the treatment liquid G671C. As the fountain solution on the printing press, a solution obtained by diluting the treatment liquid G671C with water at a ratio of 1: 1 was used.
The inks are NEW C manufactured by Dainippon Ink and Chemicals, Inc.
HAMPION F gloss 85 ink was used.

After printing, the position of the ruled line printed on the printed matter immediately after the start of printing is compared with the position of the ruled line printed on the printed matter after printing 2,000 sheets.
The plate deviation of the planographic printing plate on the plate cylinder after printing was measured. In the table showing the evaluation results, misregistration of plates and spot-like stains in non-image areas are described.

[0034]

[Table 1]

Example 2 The thickness of the aluminum foil was 3 μm, 10 μm, 50 μm,
A hard aluminum foil having a thickness of 70 μm, 90 μm, 110 μm, and 130 μm was bonded to a polyethylene terephthalate (PET) film using a nylon-based hot-melt adhesive. Change the thickness of the adhesive and PET to a total thickness of 20
An underlay sheet of 0 μm was prepared. Next, a sample was prepared in the same manner as in Example 1. Samples 21 to 34 having a convex area ratio of 0.1% and 15% having different aluminum foil thicknesses were obtained. This was printed in exactly the same manner as in Example 1 to evaluate misregistration and spot stain.

[0036]

[Table 2]

Example 3 Polyethylene terephthalate roughened to an average roughness of 0.51 μm using a hard aluminum plate having a thickness of 20 μm
A sample was prepared by bonding to the (PET) film surface using an adhesive in the same manner as in Example 1, and printing was performed after plate making. As a result, exactly the same results as in Example 1 were obtained.

Example 4 Using a stainless steel plate having a thickness of 20 μm, the same operation as in Example 1 was performed, and exactly the same results as in Example 1 were obtained.

From the above, the metal thickness of the underlay sheet was changed, and the metal was peeled off by the thickness of the metal, the area occupancy of the remaining convex portions was 0.1 to 50%, and the average of the convex portions was Height 10
It is apparent that when the thickness is 0 μm or less, misregistration during printing and spot stains are simultaneously solved.

[0040]

By using the underlay sheet of the present invention, the dimensional stability and printing workability of the plate material in a lithographic printing press can be improved satisfactorily while maintaining a good printed image. Further, the underlay sheet of the present invention is excellent in production suitability and is advantageous for cost reduction.

Claims (2)

[Claims] 1. A lithographic printing underlay sheet interposed between a plate cylinder and a lithographic printing plate having at least a back surface made of a material other than metal, wherein at least one side of the underlay sheet is
A sheet material other than metal and a metal foil having a thickness of 1 μm to 100 μm are attached to each other, and the metal foil is partially removed to form a convex portion made of an island-shaped metal foil. And an area occupancy (AN × 100) of the convex portion is 0.1 to 50%, where N is the number per unit area, and the lithographic printing underlay sheet is characterized in that: 2. The underlay sheet for planographic printing according to claim 1, wherein the surface of the portion from which the metal foil has been removed is roughened to an average roughness Ra of 1 μm or less.