JP2705940B2 - Dry lithographic manufacturing method and lithographic materials - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to dry lithographic printing, and more particularly to a method for producing a dry lithographic plate and a lithographic material that can be used in this method.

[Conventional technology]

The lithographic printing method is generally spread as an offset printing method. In a normal offset printing method, a hydrophilic portion and a lipophilic portion are formed on a printing surface, and a water called dampening water is applied to the hydrophilic portion to repel oil-based ink and not adhere thereto. The ink is applied to the blanket, transferred to a blanket once, and then retransferred to a printing medium to print.

In the above printing method, an offset printing method using no dampening solution, that is, a dry lithographic printing method, has been developed because a dampening solution management technique is difficult. This method has many advantages because no fountain solution is used.

A printing plate for a dry planographic printing plate basically has an oleophobic portion and a lipophilic portion, and ink adheres only to the lipophilic portion and does not adhere to the oleophobic portion. The oil-repellent portion is generally made of an organosilicone compound or an organic fluorine compound, and a part of the oil-repellent portion is removed by an appropriate means to expose the lipophilic portion to form an ink receiving portion to produce a printing plate. . As a method for removing the oil-repellent portion, a photochemical means is generally used. For example, there is a method of imparting photosensitivity to the oil-repellent portion layer and photo-curing the exposed portion to form an oil-repellent portion, and developing and removing the unexposed portion with a solvent or the like to form a lipophilic portion. In addition, a general photosensitive resin layer such as a diazonium compound is disposed below the oil-repellent layer (silicone rubber layer) so that the exposed portion is cured and preserved. There is also a method of removing the lipophilic portion by removing the lipophilic portion. Further, although not practically used, various methods have been proposed for a simple printing plate, such as a method of attaching a toner using an electrophotographic method.

Furthermore, a method has been proposed in which the silicone layer applied on the entire surface is locally broken to expose the substrate surface, and ink is adhered to the exposed portion (Japanese Patent Publication No. 42-21879).

[Problems to be solved by the invention]

In the method for producing a dry lithographic printing plate by the photochemical means described above, the image of the ink receiving portion has high resolution and sharpness, and a high quality printed matter can be obtained, but the plate making process is complicated and expensive. There is a problem that requires equipment and plate making time.
The method of manufacturing a dry lithographic printing plate applying electrophotography etc. for a simple printing plate is a simple, inexpensive, and quick plate making method, but it is necessary to attach an oil-repellent substance to another substance,
Because the oil-repellent substance has essentially poor affinity with other substances, the adhesion (fixation) of the oil-repellent substance to the toner is poor.
Unstable and poor printing durability.

Further, the method of locally destroying the silicone layer also has a problem that a complicated and expensive apparatus due to irradiation of an electron beam or a laser beam, discharge breakdown, and the like, and a plate making time are required.

The present invention has been made based on the above background,
The objective is to produce a dry lithographic printing plate that has high resolution and sharpness in the image area of the ink receiving section, and that can produce high-quality printed matter easily, inexpensively, and quickly. And a lithographic material that can be used in this method.

[Means for solving the problem]

The above-mentioned problems are solved by the method for producing a dry lithographic plate of the present invention and the lithographic material used therein.

That is, the method for producing a dry lithographic plate according to the present invention comprises the steps of laminating at least a support, a lipophilic heat-softening material layer and an oil-repellent material layer, and adding a foaming agent to the lipophilic heat-softening material layer and / or the oil-repellent material layer in advance. To the lithographic material
Sending a heat signal corresponding to the image symbol information, and physically or / and chemically changing the heat-softening material layer portion and the corresponding oleophobic material layer portion of the lithographic material that received the heat signal,
That is, by forming a roughened portion on the surface of the oleophobic material layer and / or a mixed portion of the lipophilic thermosoftening material and the oleophobic material by thermal softening and foaming, the lithographic material surface can correspond to the image symbol information. The lipophilic portion is formed locally.

In a preferred embodiment of the present invention, the transmission of the heat signal comprises:
This is performed by a thermal recording head having an electric heating element or by irradiation of energy rays.

The lithographic material of the present invention is a material in which at least a support, a lipophilic heat-softening material layer and an oleophobic material layer are laminated, and a foaming agent is blended in the lipophilic heat-softening material layer and / or the oleophobic material layer. The heat-softening material layer portion and the corresponding oleophobic material layer portion of the lithographic material that have received the heat signal are physically or / and chemically changed to roughen the surface of the oleophobic material layer and / or to make it lipophilic. By forming a mixed portion of a heat-softening substance and an oil-repellent substance, a lipophilic portion corresponding to image symbol information is locally formed on the surface of the planographic material.

In a preferred embodiment of the present invention, a heat-resistant film can be easily laminated on the surface of the oil-repellent substance layer.

 The present invention will be described in more detail below.

Lithographic Material The lithographic material of the present invention is a material comprising at least a support, a lipophilic heat-softening substance layer and an oleophobic substance layer.

The support that can be used in the present invention is a substrate made of a plate-making material and has mechanical strength. As such, light metals such as aluminum, other metals such as iron and copper, their alloys, plastic films such as polyester and polystyrene, paper, cloth, wood,
These include composites. The shape, dimensions, and the like of the support can be appropriately selected.

The lipophilic heat-softening substance layer used in the present invention has lipophilicity (also referred to as ink-philicity) and heat-softening property (in the specification of the present application, heat-softening property is a concept including hot-melt property). Substance. Specifically, at 40-180 ° C,
Preferably an organic material that easily softens or melts at 50 to 130 ° C., for example, a thermoplastic synthetic resin, a natural resin,
There are waxes and the like, such as natural waxes such as whale wax, carnauba wax, candelilla wax, wood wax, beeswax, montan wax, lanolin wax, paraffin wax, microcrystalline wax, ester wax, oxidized wax, low wax Synthetic waxes such as polyethylene wax and paraffin chloride, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, furomenic acid and behenic acid, higher alcohols such as stearyl alcohol and behenin alcohol, and fatty acid esters of sucrose , Esters such as fatty acid esters of sulbitan, amides such as stearinamide and oleinamide, vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polystyrene and polyvinyl acetate; Vinyl copolymer Li acetate, ethylene - acrylic acid copolymer, ethylene - methacrylic acid,
Ethylene-vinyl acetate copolymer, styrene-butadiene-acrylonitrile copolymer ethylene-α-olefin copolymer elastomer, copolymer such as saponified ethylene-vinyl acetate copolymer, cellulose resin such as ethyl cellulose and cellulose acetate ,polyethylene,
Polypropylene, acid-modified polyolefin, polyamide,
Thermoplastic resins such as polycarbonate, polysulfone, polyacetal, polymethyl methacrylate, polyphenylene oxide, polyurethane, polyethylene terephthalate, and polybutadiene terephthalate; rubbers such as synthetic rubber, chlorinated rubber, and natural rubber; and other epoxy resins, polyurethane resins, and acrylics Resin, petroleum resin, phenolic resin, polyethylene wax, montan wax, partially saponified ester wax, Fisha-Tropsch wax, oil wax, and the like.

The heat-softening layer may contain a heat transfer material such as graphite, carbon, metal powder, or a light absorbing material in order to improve heat sensitivity.

In the lithographic material of the present invention, the lipophilic heat-softening layer is
Laminated directly or indirectly on the support, the layer thickness of which is
It is 1 to 20 μm, preferably 2 to 10 μm, and can be formed by sticking or coating uniformly or unevenly and drying.

In the lithographic material of the present invention, the oleophobic substance layer is directly or indirectly laminated on the lipophilic heat-softening layer to form an ink repellent portion on the lithographic plate. The oleophobic substance has a small critical surface tension γc (dyne / cm), and is, for example, polyhexafluoropropylene, polytetrafluoroethylene, polydimethylsiloxane, polytrifluoroethylene, polyvinyl fluoride, polytrifluorochloro. There are fluorine and silicone resins such as ethylene. Also,
It is also possible to divert substances already used as oil-repellent substances in dryography, for example, the above-mentioned silicone rubber-based resins, various silicone resins such as photosensitive silicone resins having a photosensitive group introduced therein, and fluorine-based resins. it can.

In the lithographic material of the present invention, the thinner the oil-repellent material layer, the higher the thermal sensitivity and the higher the resolution, but the poorer the printing durability, so it can be selected as appropriate according to the purpose.
The thickness is 0 μm, preferably 1 to 5 μm, and it can be formed by sticking or coating uniformly or unevenly and drying.

In the present invention, a foaming agent is kneaded and compounded in the lipophilic heat-softening material layer and / or the oil-repellent material layer. Examples of the foaming agent include dinitrosopentamethylenetetramine (190 to 205 ° C., abbreviation DPT), N, N′-dimethyl-N, N ′
-Dinitrosoterephthalamide (105 ° C), benzenesulfonylhydrazide (90 to 95 ° C, abbreviation BSH), p-toluenesulfonylhydrazide (110 ° C, abbreviation TSH), toluene-2,4-disulfonylhydrazide (150 ° C) ), P-
Toluenesulfonylhydrazone (135 ° C), toluene-2,4-disulfonylhydrazone (145 ° C), 4,4'-
Oxybis (benzenesulfonyl hydrazide (140-160
° C), azobisisobutyronitrile (100-115 ° C), azodicarbonamide (175-200 ° C, abbreviation AZC), diazoaminobenzene (97-103 ° C, abbreviation DAB), etc. For example, there are foaming agent auxiliaries that lower the foaming temperature, for example, urea-based auxiliaries, and organic acid-based auxiliaries such as salicylic acid, phthalic anhydride, stearic acid, and lauric acid.

The blending amount of the above foaming agent can be appropriately selected and changed according to the use, purpose, and type.

An embodiment of the planographic material of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of one embodiment of a planographic material. In the lithographic material 1 of this embodiment, the heat-softening layer 3 is formed on the support 4 and the oleophobic layer 2 is further laminated thereon. The lithographic material of the present invention is not limited to the above-described embodiment, Is possible. For example, as shown in FIG.
In addition to the support 4, the heat-softening layer 3 and the oil-repellent layer 2, a sliding film 5 and a protective layer 6 can be laminated on the surface of the oil-repellent layer 2. With the sliding film 5 of this embodiment, it is possible to secure the sliding with the head when the thermal head is used for transmitting the heat signal.
When a sliding film 5 having poor heat resistance is used, it contributes to imparting heat resistance and slipperiness.

The layer thickness of the sliding film can be, for example, 1 to 10 μm, and the layer thickness of the protective layer 6 can be, for example, 1 to 2 μm.

As the material of the sliding film and the protective layer, for example, polyethylene, polypropylene, polyvinyl chloride,
Polyvinylidene chloride, polystyrene, ethylene-acrylic acid copolymer, ethylene-methacrylic acid, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer elastomer, acid-modified polyolefin , Styrene-butadiene-acrylonitrile copolymer, polyamide, polycarbonate, polysulfone, polyacetal, polymethylmethacrylate, polyphenylene oxide, polyurethane, polyethylene terephthalate, polybutadiene terephthalate, nylon, polyimide and other plastics, paper such as capacitor paper, cloth, There are nonwoven fabrics and single or mixture thereof (such as coextruded films), composites and laminates.

If the film has insufficient heat resistance or is unsatisfactory in slipping, a 1-2 μm thick heat-resistant slip agent can be applied to the film. In this layer, a three-dimensional heat-resistant resin such as an acrylic resin or a slipping agent such as microsilica can be mixed.

The method of manufacturing a dry lithographic plate according to the present invention includes the steps of: transmitting a heat signal corresponding to image symbol information to the lithographic material described in detail above; receiving a heat signal; The oil-repellent material layer portion is physically or / chemically changed, that is, a heat-softening material is thermally softened or melted, and a foaming agent is foamed to form a mixed portion of the oil-repellent layer and the lipophilic material. Alternatively, the method includes roughening the surface of the oleophobic layer to form a lipophilic portion corresponding to the image symbol information on the surface of the planographic material.

In the present invention, the transmission of the heat signal corresponding to the image symbol information is carried out from the oil-repellent layer side or the support side using an appropriate device.

According to the present invention, the transmission of the heat signal can be performed by a thermal recording head (thermal head) having an electric heating element or by irradiation of an energy ray.

When using a thermal recording head, the heating element of the thermal head is brought into contact with the oleophobic layer in the embodiment of FIG. 1 and in contact with the protective layer in the embodiment of FIG. A heat signal can be sent. In this case, the heat signal can be transmitted using a thermal head in an output device such as a normal personal computer, facsimile, or word processor.

On the other hand, it is possible to transmit a heat signal by irradiating energy rays such as infrared rays, ultraviolet rays, visible light, X-rays, and electron beams. The mode of irradiation of this energy ray is, for example,
A mask plate such as a halftone dot photographic original plate or metal original plate can be superimposed on the oleophobic layer surface of the lithographic material, and the whole surface can be irradiated with energy rays.Also, an argon laser or He-Cd laser beam can be narrowed down. ON-OFF repeatedly to perform scanning. That is, an appropriate image may be flash-exposed as a light-shielding mask and drawn with a high-power laser beam.

Next, an embodiment of the method for producing a dry lithographic plate according to the present invention will be specifically described with reference to the accompanying drawings. FIG. 3 is a sectional view showing each step of the embodiment.

In this embodiment, a lithographic material 1 comprising a support 4, a heat-softening layer 3 and an oil-repellent layer 2 is prepared, and a thermal head 7 is brought into contact with or close to the surface of the oil-repellent layer 2 to obtain image symbol information from the head 7. A corresponding signal is sent out, and the heat-softening layer thermally melts and foams via the oil-repellent layer 2 (FIG. 3A). As a result, the corresponding portion of the oleophobic layer 2 thereon is altered by the change of the thermal softening layer, the lipophilic component of the thermal softening layer is at least partially exposed, and the surface is roughened, so that the ink receiving portion 8 is formed. The formed oil-repellent layer remaining becomes the ink repelling portion 9 (third ink-repelling layer).
Figure B).

FIG. 3C shows another aspect of the change. In this aspect,
This is the case where the oil-repellent layer is relatively thick or has good film properties. In this case, the surface of the corresponding portion of the oil-repellent layer is roughened.

What is the method for producing a dry planographic plate according to the present invention? The present invention is not limited to the above example, and various modifications are possible. For example, as shown in FIG. 4, a mask plate such as a halftone photographic original plate or a metal original plate,
That is, the transparent original plate 10 is overlaid on the surface of the oil-repellent layer 2 of the lithographic material 1 composed of the support 4, the heat-softening layer 3 and the oil-repellent layer 2, and a heat signal is transmitted by applying a xenon flash or infrared exposure 11. The heat-softening layer is physically or / and chemically changed via the oil-repellent layer 2 (FIG. 4A). As a result, the corresponding portion of the oleophobic layer 2 thereon is altered by the change of the thermal softening layer, the lipophilic component of the thermal softening layer is at least partially exposed, and the surface thereof is roughened, and the ink receiving portion is formed. 8 are formed, and the remaining oil-repellent layer becomes the ink repelling portion 9 (FIG. 4B).

When a protective film or the like is laminated on the oil-repellent layer, the protective film is peeled off after recording.

The obtained dry lithographic plate can be used as an original plate in a usual dry lithographic method.

(Operation)

The present invention configured as described above operates as follows.

When, for example, a thermal head is brought into contact with or close to the surface of the oil repellent layer of the lithographic material and a signal corresponding to the image symbol information is transmitted from the head, heat reaches the thermal softening layer via the oil repellent layer, and this heat The softened layer portion softens or melts and is deformed by the contact pressure of the head. In addition, since the lipophilic heat-softening material layer and / or the oil-repellent material layer contains the foaming agent, the foaming agent is decomposed by heat to foam the heat-softening material layer and / or the oil-repellent material layer. As a result, the corresponding portion of the oil-repellent layer on which the heat-softening layer was supported is altered, and the lipophilic component of the heat-softening layer is at least partially exposed, and the surface is roughened. In some cases, the oil-repellent layer remains, but the corresponding portion of the oil-repellent layer is locally foamed and roughened, and the roughened surface shows ink receptivity. Thus, the ink receiving portion is formed, and the remaining oil-repellent layer becomes the ink repelling portion. This pattern corresponds to the transmitted image symbol information, and dry lithographic printing can be performed using the obtained dry lithographic plate.

When a heat signal is transmitted by irradiating energy rays such as infrared rays, ultraviolet rays, visible light, X-rays, and electron beams, when the oil-repellent layer is transparent, the oil-repellent layer directly reaches the heat-softening layer and undergoes light / heat conversion. As a result, the heat-softened layer portion softens or melts and foams as described above. When the oil-repellent layer is not transparent, light / heat conversion is performed by the oil-repellent layer, and the heat-softened layer is softened or melted and foamed in the same manner as described above.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

Judging from the above configuration and operation, as shown in the following examples, the image of the ink receiving portion has a high resolution and sharpness, and a dry lithographic printing plate capable of obtaining a high quality printed matter. Simple, inexpensive version using existing word processor, etc.
And it can be manufactured quickly.

〔Example〕

 The present invention will be specifically described by the following examples.

Example 1 On a polyester film having a thickness of 0.2 mm, a heat-sensitive melting layer (melting temperature of 70 to 100 ° C.) having the following composition was applied to a thickness of 5 μm.

Composition of heat-sensitive melting layer Ethylene-vinyl acetate copolymer (Sumitomo Chemical) ... 9 g Carnauba wax (manufactured by Kato Yoko) ... 38 g Parafil 155F (manufactured by Nippon Seisaku) ... 38 g Carbon black ... 10 g 4,4'-oxybis (benzenesulfonyl) Hydrazide: 5 g Next, a silicone rubber was applied in a thickness of 1 to 3 μm and dried to prepare a lithographic material.

Using a 16-dot / mm thermal recording head (commercial thermal recording printer) to print characters from a word processor on the silicone surface of the resulting lithographic material, the silicone rubber surface was destroyed and the wax component was exposed. .

The obtained planographic printing plate was set on an offset light printing press, and printing was performed using a commercially available ink for dryography. The obtained printed matter had good resolution and sharpness.

Example 2 A photographic film of black and white characters was brought into close contact with the silicone surface of the lithographic material used in Example 1, and was irradiated several times continuously with a 1 KW xenon flash. Next, when the photographic film was peeled off, the portion of the silicone rubber surface corresponding to the transparent portion was destroyed, and a lithographic printing plate was obtained.

The obtained planographic printing plate was set on an offset light printing press, and printing was performed using a commercially available ink for dryography. The obtained printed matter had good resolution and sharpness.

Example 3 The silicone surface of the lithographic material used in Example 1 was 3 μm thick.
Stretch the thin polyester film uniformly to 50-60
Crimping was performed at ℃. When characters from a word processor were printed on the film surface using a thermal recording head (commercially available thermal recording printer), the thermal recording head ran extremely smoothly and a stable recording operation could be performed. After recording, peel off the polyester film,
The silicone rubber surface was destroyed and the wax component was exposed. Since the polyester film was thin, the resolution of the record was not impaired.

The obtained planographic printing plate was set on an offset light printing press, and printing was performed using a commercially available ink for dryography. The obtained printed matter had good resolution and sharpness.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a planographic material according to the present invention, and FIG.
FIG. 3 is a sectional view showing another example of the lithographic material, FIG. 3 is a sectional view showing each step of one embodiment of the manufacturing method of the present invention, and FIG. 4 is a sectional view showing each step of another embodiment of the manufacturing method of the present invention. It is sectional drawing. 1 ... planographic material, 2 ... oil-repellent layer, 3 ... thermal softening layer, 4 ...
... Support, 5 ... Sliding film, 6 ... Protective layer, 7 ...
Thermal head, 8: ink receiving section, 9: ink repelling section, 10: transparent original plate, 11: flash.

Claims (2)

(57) [Claims] A lithographic material comprising a support, a lipophilic heat-softening substance layer and an oil-repellent substance layer at least laminated, and a foaming agent blended in the lipophilic heat-softening substance layer and / or the oil-repellent substance layer. A heat signal corresponding to the image symbol information is transmitted, and the heat-softening material layer portion and the corresponding oil-repellent material layer portion of the lithographic material that have received the heat signal are physically or / and chemically changed to change the heat repellency. By forming a roughened part on the surface of the oily substance layer and / or a mixed part of the lipophilic heat-softening substance and the oleophobic substance, a lipophilic part corresponding to the image symbol information is locally formed on the surface of the planographic material. A method for producing a dry lithographic plate, characterized in that the lithographic plate is formed into a lithographic plate. 2. A material comprising at least a support, a lipophilic heat-softening substance layer and an oleophobic substance layer, wherein a foaming agent is blended in the lipophilic heat-softening substance layer and / or the oleophobic substance layer. A flat plate material characterized in that: