JPH10296945A - Formation of ink jet type process printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a hot melt form ink jet type process printing plate with which many sheets of printed matter of a distinct image which is free from ground fog can be printed. SOLUTION: In a method for making a lithographic printing plate wherein an image is formed on an intermediate transfer body by injecting an ink liquid drop in a hot melt state from a nozzle, and the image on the intermediate transfer body is formed by contact transfer on a receiving layer of an original plate for direct drawing type lithographic printing, for the image receiving layer, silica particle of 1 to 6 μm mean particle size and colloidal inorganic pigment ultra fine particle of 10 to 50 nm mean particle size are used by a (40-70) to (60-30) by wt. ratio are used as the inorganic pigment, gelatin is used within a range of (85-40) to (15-50) by wt., ratio of inorganic pigment to gelatin as hydrophylic bond resin, and the image receiving layer containing them is waterproof by being set with gelatin setting compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a lithographic printing plate using an ink-jet recording system, and more particularly to a method for preparing a hot-melt ink-jet type plate-making printing plate having good plate making quality and printing quality. .

[0002]

2. Description of the Related Art With the recent development of office equipment and the development of OA, in the field of light printing, a direct-drawing lithographic printing plate precursor having a hydrophilic surface image-receiving layer on a water-resistant support is produced by various methods. 2. Description of the Related Art Offset lithographic printing, in which a plate is made, that is, an image is formed to create a printing plate, has become widespread.

[0003] A conventional direct-drawing lithographic printing plate material comprises an image-receiving layer containing an inorganic pigment, a water-soluble resin, a water-proofing agent, etc., on a support made of water-resistant paper or a plastic film. A lipophilic image is formed on such a direct-drawing lithographic printing plate using a lipophilic ink by a typewriter or handwriting, or the image is thermally melt-transferred from an ink ribbon by a thermal transfer printer. Alternatively, there is known a method of forming a printing plate by forming an oleophilic image with an ink jet printer using a liquid ink.

As components constituting the image receiving layer of this plate material, conventionally, as inorganic pigments, kaolin, clay, talc, calcium carbonate, silica, titanium oxide, zinc oxide,
Barium sulfate, alumina and the like are mentioned.

As the water-soluble resin, modified PVA such as polyvinyl alcohol (PVA) and carboxy PVA;
Starch and its derivatives, carboxymethylcellulose,
Water-soluble resins such as cellulose derivatives such as hydroxyethyl cellulose, casein, gelatin, polyvinylpyrrolidone, vinyl acetate-crotonic acid copolymer, and styrene-maleic acid copolymer are mentioned.

Glyoxal is used as a waterproofing agent,
Initial condensate of aminoblast such as melamine formaldehyde resin, urea formaldehyde resin, modified polyamide resin such as methylolated polyamide resin, polyamide / polyamine / ebichlorohydrin adduct, polyamide ebichlorohydrin resin, modified polyamide polyimide resin, etc. Are listed.

It is also known that ammonium chloride and a crosslinking catalyst for a silane coupling agent can be used in combination.

In recent plate making by various printers, the image receiving layer of the original plate has hydrophilicity which does not cause stains of printing ink as a lithographic printing plate, as well as water resistance.
Furthermore, adhesion to the formed lipophilic image layer is required as an important point, and various proposals have been made.

For example, zinc oxide, kaolinite and alumina are used as inorganic pigments, and a water-soluble resin, a water-proofing agent and acetic acid are coexisted and dispersed therein, during which acetic acid and zinc oxide react to replace zinc acetate. Receiving layer formed by applying the dispersed material (Japanese Patent Application No. 63-54288).
No.), an image receiving layer using talc or silica instead of alumina and using a metal compound of aluminum, zirconium, or titanium as a water-proofing agent in the above-mentioned method. (Japanese Patent Application Nos. 63-166590 and 63-166593)
It has been proposed that the hydrophilicity and water resistance can be improved by such methods.

Further, when plate making is performed by an electrophotographic printer (PPC copier) using dry toner, toner adheres to the non-image portion of the plate that has been formed, and when this is printed as a printing plate, background contamination occurs on printed matter. As a countermeasure against this problem, for example, a method of adjusting the surface roughness of the image receiving layer to a specific roughness using an inorganic pigment such as silica having an average particle size of 5 to 20 μm (Japanese Patent Publication No. 6-96353), A method is disclosed in which silica and alumina sol each having an average particle size of 5 to 20 μm are used in combination as pigments (JP-A-62-157058).

In addition to PPC copiers, as a technique for improving the adhesion of ink to non-image areas and the lack of adhesion of ink images in plate making with a thermal transfer printer, colloidal silica having a particle size of 20 nm or less is used. A method using a combination of a pigment such as calcium carbonate and a lubricant such as a polyethylene wax emulsion (JP-A-6-183164)
), A method of using a synthetic silica powder having a particle diameter of 20 μm or less in combination with a hydrophilic resin of colloidal silica having a particle diameter of 50 μm or less and polyvinyl alcohol (Japanese Patent Publication No. 5-178)
No. 71) and the like are disclosed.

However, the printing plate prepared by such a method has insufficient mechanical strength in the image area, and the image area is easily cut off when printed, and the background fog is conspicuous in the non-image area. Met.

[0013]

On the other hand, as described above,
With the spread of various OA devices, various computers and their peripheral devices, and the development of technology, lithographic printing of images created by editing using personal computers or workstations directly from various printers compatible with digital output signals. A method of making a plate on a plate has become possible.

[0014] In plate making using an ink jet printer capable of supporting digital signals, a method for eliminating the problem of diffusion and absorption of an image forming agent in a liquid on a plate material which occurs when using a liquid ink and reducing image bleeding. Japanese Patent Application Laid-Open No. 64-27953 discloses a hot-melt ink-jet method (also referred to as a solid-jet method) using a hydrophobic solid ink as a liquid by heat melting.

However, also in this method, when a printing plate is actually formed and printed, blurring of the image portion is observed, and background contamination due to the adhesion of the printing ink is conspicuous in the non-image portion, and the number of printed sheets is also reduced. At most, about two to three hundred sheets were the limit, which was insufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a hot-melt ink-jet type plate-making printing plate capable of printing a large number of clear printed images without fog. It is to provide a creation method.

[0017]

The above object is achieved by the following.
This is achieved by the present invention of (1) to (6). (1) An ink composition which is solid at normal temperature is melted by heat, droplets of the ink in the melted state are ejected from a nozzle to form an image on an intermediate transfer member, and an inorganic pigment and a hydrophilic pigment are formed on a water-resistant support. The image of the intermediate transfer body is formed on the image receiving layer of the direct drawing type lithographic printing plate precursor provided with the image receiving layer mainly composed of the conductive binder resin by the hot melt type ink jet method in which the image is formed by contact transfer. In the method of forming a lithographic printing plate by forming the image receiving layer, as the inorganic pigment,
Silica particles having an average particle diameter of 1 to 6 μm and an average particle diameter of 1
The colloidal inorganic pigment ultrafine particles of 0 to 50 nm are used in a weight ratio of 40 to 70 to 60 to 30, and gelatin is used as the hydrophilic binder resin in a weight ratio of the inorganic pigment to gelatin of 85 to 40. A method for preparing an ink-jet type plate making plate, wherein the image receiving layer is used in the range of 15 to 60 and contains water and is cured by a gelatin curable compound. (2) The method of (1) above, wherein the surface of the image receiving layer of the lithographic printing plate precursor has a Beck smoothness of 30 to 500 (sec / 10 cc). (3) The method for producing an ink-jet type plate-making printing plate according to the above (1) or (2), wherein the surface of the support on the side adjacent to the image receiving layer has a Beck smoothness of 300 (sec / 10 cc) or more. . (4) An average particle diameter of 10 to 5 contained in the image receiving layer
The method for producing an ink-jet plate-making printing plate according to any one of the above (1) to (3), wherein the 0 nm colloidal inorganic pigment ultrafine particles are colloidal silica, alumina sol or titanium oxide ultrafine particles. (5) The above (1) to (4), wherein the gelatin curable compound contained in the image receiving layer is a compound containing two or more double bond groups represented by the following general formula (I) in a molecule.
The method for producing an ink-jet type plate-making printing plate according to any one of the above. In the general formula _{(I) CH 2 = CH-} X- formula (I), _{X, -OSO 2 -, - SO 2} -, - CON
R- or an -SO ₂ NR-. (However, R represents a hydrogen atom or an aliphatic group having 1 to 8 carbon atoms.) (6) The ink composition has a wax having a melting point of 50 to 150 ° C., a resin, a coloring material, and an adhesion modifier. And producing a hot-melt liquid by heating to 80 ° C. or higher, wherein the viscosity of the hot-melt liquid is 1 to 20 cps or more. Method.

[0018]

Embodiments of the present invention will be described below in detail. The present invention provides a hot-melt ink-jet ink-jet printing method in which a hydrophobic ink composition which is a solid image forming member at normal temperature (35 ° C. or lower) is formed on an image receiving layer composed of a silica / colloidal ultrafine particle / cured gelatin film. Or by a solid jet method, and forming an image via an intermediate transfer body, the formed image layer,
Affinity with the adhered or adhered image receiving layer is sufficiently maintained, and a strong image portion is formed in which the image layer is less likely to be missing.

The image receiving layer provided on the water-resistant support of the present invention contains, as main components, an inorganic pigment, gelatin and a gelatin-hardening compound as a water-proofing agent.

The inorganic pigment contains silica particles having an average particle size of 1 to 6 μm and ultrafine colloidal inorganic pigment particles having an average particle size of 10 to 50 nm.

The silica particles used in the present invention preferably have an average particle size of 1.0 to 4.5 μm. Silica particles are
It is an amorphous synthetic silica fine powder containing silicon dioxide as a main component (99% or more) and having no crystal structure.

Specifically, it is described in "Applied Technology of High Purity Silica", Chapters 4 and 5, supervised by Yoshitoshi Kaga and Akira Hayashi, published by CMC Corporation (1991).

The synthetic silica fine powder of the present invention has an average particle diameter of 1 to 6 μm in which the porosity and the pore volume are adjusted, but the pore diameter and the pore volume, and the oil absorption,
The surface silanol group density and the like are not particularly limited. These synthetic silica fine powders can be easily obtained as commercial products.

As the ultrafine particles of the colloidal inorganic pigment having an average particle diameter of 10 to 50 nm, conventionally known compounds can be mentioned. Preferred are silica sol, alumina sol, titanium oxide, magnesium oxide and magnesium carbonate. More preferred are silica sol, alumina sol and ultrafine titanium oxide.

The silica sol has many hydroxyl groups on the surface,
Inside, ultrafine silica particles having a particle diameter of 1 to 100 nm constituting a siloxane bond (-Si-O-Si-) are dispersed in water or a polar solvent, and are also called colloidal silica. is there. Specifically, it is described in Chapter 3 of the aforementioned book "Applied Technology of High Purity Silica".
Alumina sol is an alumina hydrate (boehmite type) having a colloidal size of 5 nm to 200 nm, and an anion in water (for example, a halogen atom ion such as fluorine ion and chloride ion, a carboxylate anion such as acetate ion, etc.). Is dispersed as a stabilizer.

The above colloidal fine particles having an average particle diameter of 10
〜50 nm are provided for the present invention. Preferably 10
The average particle size is 40 nm. These colloidal inorganic pigment ultrafine particles can be easily obtained as commercial products.

Only when the particle diameter of each of the silica particles and the colloidal inorganic pigment ultrafine particles used as the inorganic pigment of the present invention is within the above range, the film strength of the image receiving layer is sufficiently maintained, and the hydrophobic room temperature (35) When the ink composition is a solid image forming member at a temperature of not more than 0 ° C.), an image is formed by a solid jet method to form a printing plate. A clear image without bleeding or the like is obtained.

The silica particles and the ultrafine particles of the colloidal inorganic pigment are present in a weight ratio of 40 to 70 to 60 to 30, preferably 50 to 60 to 50 to 40.

In the present invention, gelatin used as a hydrophilic binder resin is a kind of derived protein, and is not particularly limited as long as it is called gelatin produced from collagen. The gelatin preferably has a pale, transparent, tasteless and odorless appearance. Further, gelatin for photographic emulsions is more preferable because physical properties such as viscosity and gel jelly strength in an aqueous solution are within certain ranges.

In the image receiving layer of the present invention, gelatin is used as the hydrophilic binder resin in a weight ratio of the inorganic pigment to the gelatin in the range of 85 to 40 to 15 to 60, preferably 85 to 60 to 15. Used in a weight ratio of ４０40.

Within this range, effects such as the strength of the film, the prevention of adhesion of the printing ink to the non-image area, and the improvement of the adhesion to the image area (press life) are obtained in the same manner as described above.

Further, the image receiving layer of the present invention is used together with a gelatin curable compound to cure the layer so as to have good water resistance.

As the gelatin hardening compound, conventionally known compounds can be used. For example, THJames
"The Theory of the Photographic Process," Chapter 2, Section III, Macmillan Puplishing Co. Inc. (197
7th year), Research Disclosure Magazine No. 176
43, P26 (issued in December 1970) and the like. Preferably, dialdehydes and diketones of succinaldehyde, glutaraldehyde, adipaldehyde (for example, 2,3-butanedione, 2,5-hexanedione, 3-hexene-2,5-dione, 1,2- Active olefin compounds having two or more double bonds in which electron-withdrawing groups are adjacently bonded to each other.

More preferably, the compound contains two or more double bond groups represented by the following general formula (I) in the molecule.

[0035] In the general formula _{(I) CH 2 = CH-} X- formula (I), _{X, -OSO 2 -, - SO 2} -, - CON
R- or an -SO ₂ NR- (where, R represents a hydrogen atom or an aliphatic group having 1 to 8 carbon atoms).

Preferably, R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may be substituted (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a methylol group,
2-chloroethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2-carboxyethyl group, 3-methoxypropyl group, etc.). More preferably, X in formula (I), -SO ₂ - represents a.

Specifically, for example, resorcinol bis (vinylsulfonate), 4,6-bis (vinylsulfonyl) -m-xylene, bis (vinylsulfonylalkyl) ether or amine, 1,3,5-tris ( Vinylsulfonyl) hexahydro-s-triazine, diacrylamide, 1,3-bis (acryloyl) urea,
N, N'-bismaleimides and the like can be mentioned.

The gelatin hardening compound is gelatin 100
The amount is preferably 0.5 to 20 parts by weight based on part by weight. More preferably, it is 0.8 to 10 parts by weight.

The image receiving layer of the present invention constructed as described above maintains its own film strength sufficiently, and
Adhesion with the surface of the water-resistant support described below is sufficient and no film loss occurs during printing. When a printing plate is formed by forming an image of a hydrophobic ink composition which is a solid image forming member at normal temperature (35 ° C. or less) by a solid jet method, fine images such as fine lines, fine characters, and halftone dots are formed. The part is a clear image without any missing, distortion, or bleeding.

Further, when printed as a printing plate, the printing ink is extremely hydrophilic and does not cause adhesion of the printing ink to the non-image area, and at the same time, has good adhesion to the image area.
An excellent effect that no loss of an image occurs even when 1,000 or more sheets are printed is exhibited.

In the image receiving layer of the present invention, in order to improve the applicability of the image receiving layer coating dispersion, an interface controlling agent (surface-regulating agent), an antifoaming agent, and a film pH adjusting agent are provided. Various additives such as a buffer may be used in combination.

The thickness of the image receiving layer in the present invention is preferably about 3 to 30 g, as indicated by the applied amount of the image receiving composition per 1 m ² of the original plate (after drying).

In the present invention, the smoothness of the surface of the image receiving layer is preferably 30 to 500 (sec / 10 cc) or more, more preferably 45 to 300, in Beck smoothness.
(Second / 10 cc).

When the smoothness of the surface of the image receiving layer is within the above-mentioned range, a clear image without image defects or the like is formed, and the adhesion between the image portion and the image receiving layer is improved. The printing durability is significantly improved to 1000 sheets or more.

Here, the Beck smoothness can be measured by a Beck smoothness tester. A Beck smoothness tester is a tester in which a test piece is pressed at a constant pressure (1 kg / cm ² ) on a highly smooth finished circular glass plate having a hole at the center, and a fixed amount (10 cc) is obtained under reduced pressure. It measures the time required for air to pass between the glass surface and the specimen.

The image receiving layer of the present invention is provided on a water-resistant support. As the water-resistant support, paper, a plastic film or a paper or a plastic film laminated with a metal foil, which has been subjected to a water-resistant treatment can be used.

The support used in the present invention has a surface smoothness on the side adjacent to the image receiving layer having a Beck smoothness of 300.
(Sec / 10 cc) or more, preferably 900 to 3000
(Sec / 10 cc), more preferably 1000 to 3000 (sec / 10 cc).

By regulating the smoothness of the surface of the support on the side adjacent to the image receiving layer to a Beck smoothness of 300 (sec / 10 cc) or more, image reproducibility and printing durability can be further improved. . Such an improvement effect can be obtained even if the smoothness of the image receiving layer surface is the same, and the adhesion between the image portion and the image receiving layer is improved by increasing the smoothness of the support surface. Conceivable.

The highly smooth surface of the water-resistant support thus regulated refers to the surface on which the image receiving layer is directly applied. For example, an underlayer and an overcoat layer described later are provided on the support. In this case, it refers to the surface of the underlayer or overcoat layer.

As a result, the image receiving layer whose surface condition has been adjusted as described above is sufficiently retained without receiving any irregularities on the surface of the support, and the image quality can be further improved.

As a method for setting the smoothness within the above range, various conventionally known methods can be used. Specifically, a method of adjusting the Beck smoothness of the surface of the support by a method such as a method of melting and bonding the substrate surface with a resin, a method of strengthening a calendar with a highly smooth heat roller, and the like can be used.

In the present invention, as a method for melt-bonding the resin, it is preferable that the resin is coated by an extrusion lamination method. By coating by this extrusion lamination method, a support having a desired smoothness can be produced. The extrusion laminating method is a method in which a resin is melted, formed into a film, immediately pressure-bonded to base paper, and then cooled and laminated, and various apparatuses are known.

The thickness of the resin layer laminated in this manner is 10 μm or more from the viewpoint of production stability. Preferably it is 10 μm to 30 μm.

Here, examples of the resin include a polyethylene resin, a polypropylene resin, an acrylic resin, a methacrylic resin, an epoxy resin, and a copolymer thereof. Also, two or more of these resins can be used. Among them, polyethylene resin is preferable. Among polyethylene-based resins, a mixture of low-density polyethylene and high-density polyethylene is particularly preferred. Thereby, the coating film has uniformity and excellent heat resistance. Furthermore, by using this mixture, when a conductive substance as described later is added to the resin layer, the conductivity becomes more excellent.

The low-density polyethylene described above has a density of 0.915 to 0.930 g / cc and a melt index;
The high-density polyethylene preferably has a density of 0.940 to 0.970 g / cc and a melt index of 1.0 to 30 g / 10 minutes. As the blend ratio, low density polyethylene 10
Preferably, it is 90 to 90% by weight and 90 to 10% by weight of high density polyethylene.

When a base paper is used as the base, an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ethylene-acrylate copolymer are pre-coated on the base paper in order to improve the adhesive strength between the base paper and the resin layer. Methacrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylonitrile-acrylic acid copolymer, ethylene-acrylonitrile-
It is preferable to apply a polyethylene derivative such as a methacrylic acid copolymer or to perform corona discharge treatment on the surface of the base paper. As another method, JP-A-49-24126, 5
Nos. 2-36176, 52-121683 and 53-
No. 2612, No. 54-111331 and Japanese Patent Publication No. 51
The surface treatment described in each publication of JP-A-25337 can be applied to the base paper.

Another method of strengthening the calendar is achieved by calendering a substrate such as paper described below or a support having an underlayer formed on the substrate. Here, the calendering conditions are appropriately controlled by the composition of the substrate and the underlayer, and include the types and combinations of rolls such as metal rolls, resin rolls, and cotton rolls, the number of calender rolls, roll nip pressure, roll surface temperature, and the like. Can be appropriately selected.

Further, in the present invention, as described above, an under layer is provided between the support and the image receiving layer for the purpose of improving water resistance and interlayer adhesion, and a curl prevention is provided on the surface of the support opposite to the image receiving layer. A backcoat layer (backside layer) can be provided for the purpose, but the smoothness of the backcoat layer is preferably in the range of 150 to 700 (sec / 10 cc).

Thus, when a printing plate is supplied to an offset printing press, the printing plate is accurately set on the printing press without causing displacement or slippage.

When the smoothness of the underlayer and the backcoat layer of such a support are individually adjusted, for example, a calendering process is performed once after the underlayer is formed, and a calendering process is performed again after the backcoat layer is formed. In addition, the process of calendar processing is performed multiple times,
It is desirable to control the smoothness by a combination of adjusting the composition of the under layer and the back coat layer, for example, the proportion and particle size of the pigment, and adjusting the calendering conditions as described below.

Examples of the substrate used in the master plate of the present invention include substrates such as wood pulp paper, synthetic pulp paper, mixed paper of wood pulp and synthetic pulp, non-woven fabric, plastic film, cloth, metal sheet, and composite sheet materials thereof. Can be used as it is. Further, in order to obtain the smoothness specified in the present invention, and to adjust the water resistance and other properties, a hydrophobic resin used for an under layer or a back coat layer described below on the substrate, water dispersibility or A coating made of a water-soluble resin, a pigment, or the like may be impregnated.

In the present invention, underprinting properties such as recording characteristics, water resistance, and durability required for a lithographic printing original plate are satisfied, and an undercoat is formed on the substrate to adjust to a desired smoothness as described above. It is preferable to use a support provided with a layer and a back coat layer. Such an under layer and a back coat layer are formed by applying a coating solution containing a resin, a pigment, and the like on a support, drying and laminating the coating solution. Various resins are appropriately selected and used as the resin used here. Specifically, as the hydrophobic resin, for example, an acrylic resin, a vinyl chloride resin, a styrene resin, a styrene-butadiene resin,
Styrene-acrylic resin, urethane-based resin, vinylidene chloride-based resin, vinyl acetate-based resin, and the like.Examples of hydrophilic resin include polyvinyl alcohol-based resin, cellulose-based derivative, starch and its derivatives, polyacrylamide-based resin, and styrene. Maleic anhydride copolymers and the like can be mentioned.

Examples of the pigment include clay, kaolin, talc, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica and the like. These pigments are used to achieve the desired smoothness.
It is preferable to select the particle size appropriately and use it. For example, since a relatively high degree of smoothness is required in the under layer, small particles or large particles are cut to specifically 8 μm or less. Preferably, a pigment having a particle size of about 0.5 to 5 μm is used. Further, since a lower smoothness is required in the back coat layer as compared with the under layer, a larger particle size, specifically, 0.5 to 10
Pigments having a particle size of about μm are preferably used. The above pigment is preferably used in an amount of 80 to 150 parts by weight in the under layer and 80 to 200 parts by weight in the back coat layer, based on 100 parts by weight of the resin. In order to obtain excellent water resistance, it is effective for the under layer and the back coat layer to contain a water-resistant agent such as a melamine resin or a polyamide epichlorohydrin resin. The particle size can be measured by a scanning electron microscope (SEM) photograph. Also,
When the particles are not spherical, the diameter is obtained by converting the projected area into a circle.

In order to prepare the lithographic printing plate precursor of the present invention, a solution containing an under layer component is coated on one side of the support, if necessary, and dried to form an under layer. A solution containing a component of a back coat layer is applied to the surface and dried to form a back coat layer, and then a coating solution containing a component of an image receiving layer is applied and dried to form an image receiving layer. Note that the image-receiving layer, the under layer, the coating amount of the backcoat layer are each 1 to 30 g / m ^2, in particular 6~20g / m ²
Is appropriate.

More preferably, the water-resistant support provided with an under layer or a back coat layer has a thickness of 9
0 to 130 μm, preferably 100 to 120 μm
Range.

Next, a description will be given of a solid ink which is an ink composition which is solid at room temperature and which is used in a hot-melt type ink jet system (or a solid jet system).

As described above, the solid ink used in the present invention is solid at a temperature of 35 ° C. or lower, and has a temperature of 80 ° C. to 1 ° C.
It becomes a hot-melt liquid when heated to 50 ° C., and has a viscosity at the time of hot-melt in the range of 1 cps to 20 cps, preferably 2 cps to 15 cps, and a conventionally known liquid can be used.

Specifically, the hot-melt ink of the present invention comprises:
30% of a wax which is solid at ordinary temperature and has a melting point of 50 ° C to 150 ° C, a resin, a coloring material, and an adhesion modifier, and preferably has a melting point of 50 ° C to 150 ° C. 90% by weight and 5-70% by weight of resin
And 0.1 to 10% by weight of a dye or pigment as a coloring material, and 2 to 40% by weight of an adhesion modifier as ink components.

Melting point 5 used as one component of vehicle
As a wax at 0 ° C. to 150 ° C., a so-called room temperature solid wax, a wax that is thermally stable at least at the ink discharge temperature of an inkjet printer in a heated and melted state at a melting point or higher is used.

Examples of the wax include petroleum wax, preferably paraffin wax or microcrystalline wax; vegetable wax, preferably candelilla wax, carnauba wax, rice wax, or jojoba solid wax; animal wax; Preferably beeswax, lanolin or spermaceti; mineral waxes, preferably montan wax; synthetic hydrocarbons;
Preferably Fischer-Tropsch wax or polyethylene wax; hydrogenated wax, preferably hydrogenated castor oil or hydrogenated castor oil derivative;
Preferably a montan wax derivative, a paraffin wax derivative, a microcrystalline wax derivative or a polyethylene wax derivative; a higher fatty acid, preferably behenic acid, stearic acid, palmitic acid, myristic acid, or lauric acid; a higher alcohol, preferably stearyl alcohol; Or behenyl alcohol or;
Hydroxystearic acid, preferably 12-hydroxystearic acid or a 12-hydroxystearic acid derivative; ketone, preferably stearone or lauron; fatty acid amide, preferably lauric amide, stearic amide, oleic amide, erucamide,
Ricinoleic acid amide, 12-hydroxystearic acid amide, special fatty acid amide or N-substituted fatty acid amide; an amine, preferably dodecylamine, tetradecylamine or octadecylamine; an ester, preferably methyl stearate, octadecyl stearate;
Any of conventionally known waxes such as glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, ethylene glycol fatty acid ester, or polyoxyethylene fatty acid ester; and polymerized wax, preferably α-olefin maleic anhydride copolymer wax; Can be used without any particular limitation. These waxes may be used alone or as a mixture of two or more kinds. It is desirable that the wax be contained in the range of 30 to 90% by weight based on the whole ink.

The resin used as one component of the vehicle together with the wax not only functions to impart adhesiveness to printing paper, control the viscosity of the ink, and also hinder the crystallinity of the wax, but also imparts transparency to the ink. It also works to give.

The resin is preferably an oil-soluble resin. As the oil-soluble resin, for example, an olefin resin,
Preferably a polyethylene resin, a polypropylene resin or a polyisobutylene resin; or a vinyl resin, preferably an ethylene-vinyl acetate copolymer resin, a vinyl chloride-vinyl acetate copolymer resin or a vinyl acetate resin or ethylene-
Vinyl chloride-vinyl acetate resin; acrylic resin, desirably methacrylate resin, polyacrylate resin, ethylene-ethyl acrylate copolymer resin or ethylene-methacrylic acid copolymer resin; phenol resin; polyurethane resin; Polyamide resin, polyester resin, ketone resin, alkyd resin, rosin resin, hydrogenated rosin resin, petroleum resin, hydrogenated petroleum resin, maleic acid resin, butyral resin, terpene resin, Hydrogenated terpene resins; chroman-indene resins; and the like. These resins (polymer materials) may be used alone or as a mixture of two or more kinds.
It is desirable to contain it in the range of weight%.

As the coloring material, any dyes and pigments conventionally used in oil-based ink compositions can be used.

As the pigments, those generally used in the technical field of printing can be used irrespective of inorganic pigments and organic pigments. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, pyridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo-based pigment, phthalocyanine-based Pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, and other conventionally known pigments are particularly limited. Can be used without.

As the dyes, azo dyes, metal complex dyes,
Naphthol dye, anthraquinone dye, indigo dye,
Oil-soluble dyes such as carbonium dyes, quinone imine dyes, xanthene dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine dyes and metal phthalocyanine dyes are preferred.

These pigments and dyes may be used alone or in appropriate combination, but may be contained in the range of 0.1 to 10% by weight based on the whole ink. desirable.

The adhesion modifier used effectively imparts plasticity and tackiness to the solid-state heat-meltable ink without significantly changing the viscosity, melting point, and melting energy of the ink as a whole. It functions to dramatically improve the fixing property to the recording sheet and the fixing property between the recording dots. Examples of the adhesion modifier include polyolefins and derivatives thereof (for example, polyolefin-based polyols) and the like.
Desirably, the content is in the range of ４０40% by weight.

In addition to the above, the ink of the present invention may contain various additives such as a dispersant and a rust preventive. The ink of the present invention is obtained by mixing the above materials in a heated state. The melting point of each ink can be set to various values by changing the type of constituent components to be used, and when mixing and using them, the mixing ratio.
The melting point of the ink can be measured by using a general melting point measuring device or a thermal analyzer such as DSC or DTA.

Next, a method of forming an image on the lithographic printing plate precursor (hereinafter also referred to as “master”) will be described. FIG. 1 shows an example of an apparatus system for performing such a method.

The apparatus system shown in FIG. 1 has an ink jet recording apparatus 1 of a solid jet system using solid ink.

As shown in FIG. 1, first, pattern information of an image (figure or text) to be formed on the master 2 is transmitted from an information source such as a computer 3 through a transmission means such as a path 4 to a solid. The ink is supplied to the ink jet recording apparatus 1 based on the jet method. In the inkjet recording head unit 10 of the recording apparatus 1, the solid ink is melted and stored in an ink tank, and fine droplets of the ink are sprayed on the surface of an intermediate transfer body 28 described later in accordance with the information. Thus, the ink adheres to the surface of the intermediate transfer member 28 in the pattern. The adhesion thickness, that is, the thickness of the ink layer is usually 1 to 50
μm, preferably 3 to 35 μm.

FIGS. 2 to 4 show examples of the structure of an ink jet recording apparatus as in the apparatus system of FIG. 2 to 4, members common to FIG. 1 are denoted by common reference numerals.

FIG. 2 is a schematic structural view showing a main part of such an ink jet recording apparatus. The ink jet recording apparatus of FIG. 2 transfers an ink image from an intermediate transfer surface onto a master in a rapid process. The printhead 11 deposits the supported molten ink on the intermediate transfer member 28 in a fixed or movable state with a suitable housing and support elements (not shown). The intermediate transfer body 28 may be a web or a platen other than the drum, and may be formed of an appropriate material. The intermediate transfer member 28 is not particularly limited, but a metal containing aluminum, nickel, iron phosphate, or the like, an elastomer containing fluoroelastomer, perfluoroelastomer, silicon rubber, polybutadiene, or the like, or polyphenylene sulfide is added. Even when molded using plastic containing polytetrafluoroethylene, thermoplastic resin containing polyethylene, nylon, FEP (fluorinated ethylene / propylene resin), thermosetting resin such as acetal, ceramic, etc. good. Regardless of which material is used, the exposed surface of the intermediate transfer member 28 has sufficient hardness, and the master 2 can smoothly pass between the intermediate transfer member 28 and the transfer roller 32, and It does not matter as long as there is no problem in supporting the ink. A preferred material for the intermediate transfer member 28 is anodized aluminum. The surface has a Beck smoothness of 300 seconds / 10 cc or more, preferably 800 seconds / 10 cc or more, more preferably 1000 seconds / 10 cc.
More than 3000 seconds / 10cc or less is good.

The master guide 30 shown in FIG. 2 passes the master 2 from a sheet feeding device (not shown) and guides the master 2 to an intermediate transfer section 37 sandwiched between the roller 32 and the intermediate transfer member 28. A plurality of strip fingers 38 (only one is shown) are provided in the printer device 10 so that the master 2 can be peeled off from the surface of the intermediate transfer body 28. The roller 32 has a core portion 33 made of metal (preferably made of steel), and is provided around the periphery thereof with an elastomer having a Shore D hardness of about 40 to 45. Suitable elastomeric materials can be silicone, urethane, nitrile, EPDM, or other elastic materials. The master 2 is pressed by the elastomer covering the rollers 32, and the ink image 36 is melted or fixed, and the ink image is expanded, extended and fixed.

This process, the ink used in the system of the present invention, is initially solid and becomes liquid when heated to a temperature of about 85 ° C. to about 150 ° C. A rise in temperature outside of this range will cause ink degradation or chemical decomposition. The molten ink is supplied from the ink jet holes of the print head 11 to the intermediate transfer member 28.
Fired on the surface in a raster scan format. Here, the ink cools and solidifies to a soft state, and is transferred to the master 2 sandwiched between the intermediate transfer body 28 and the roller 32 by contact transfer at the intermediate transfer unit 37. The temperature at which the ink is maintained in this flexible state is between about 30C and 80C.

The ink image in the flexible state is
When the ink image 36 is sandwiched between the intermediate transfer member 28 and the intermediate transfer member 28, the ink image 36 is deformed to a final image state, and the ink image 36 is fixed on the master 2 by the pressure from the roller 32 or by the heat from the heater 29 or the heater 31. . Further, a heater 34 may be provided to facilitate the processing at this point. The pressure applied to the ink image 36 is about 1 to
150 kgf / cm ² , more preferably about 30 to
About 100 Kgf / cm ² , the most preferred value being about 5
0 to about 60 Kgf / cm ² . This pressure must be strong enough to fix the ink image 36 to the master 2.

The ink image once fixed on the master 2 cools down to an ambient temperature of about 20 to 25 ° C. The ink in this ink image must be ductile and must be deformable without breaking even when maintained at a temperature above the glass transition temperature. Below the glass transition temperature, the ink becomes hard. The temperature of the transferred ink image that maintains the ductile and flexible state is in the range of about -10C to 120C, preferably 10C to 90C. That is, since the master 2 is usually porous as described above, the ink penetrates into the image receiving layer of the master 2 and is received.

In FIG. 2, the heater 29 may be a heat-dissipating resistance heater arranged as shown in the figure, but is best arranged in the intermediate transfer member 28. The heaters 31 and 34 are connected to the master guide 30 and the
They may be arranged in the fixing roller 32, respectively. The heater 29 controls the temperature of the intermediate transfer member 28 from about 25 ° C to about 100 ° C.
Up to A more desirable temperature range is about 40 ° C.
80 ° C.

It is preferable to preheat the master 2 to about 70 ° C. to 130 ° C. by the heater 31 before fixing the ink image 36. When the heater 34 is used, the roller 3
The temperature of 2 is raised from about 25C to about 200C. The heater 34 may be provided inside the roller 32.

Ink is ejected from the ink jet head 11 onto the surface of the intermediate transfer member 28 as described above.

FIG. 3 is a schematic structural view of the head section 10 in the ink jet recording apparatus. As shown in FIG. 3, the head unit 10 is roughly composed of an ink jet head 11 and an ink tank 20. And a means 21 for heating and melting the solid ink 25,
Such a device uses, for example, a heating resistor. Here, an example using a heating resistor will be described. A heating resistor 21 is provided in the ink tank 20 of the head unit 10.
The ink 22 melted by the above is stored, and a tank cap 23 is attached to the ink tank 20. Further, the head unit 10 is provided with the inkjet head 1.
1 has an ink supply path 24 for supplying the molten ink 22 in the ink tank 20.

When the solid ink 25 is supplied to the ink tank 20 by an operator or the like, the solid ink 25 is heated and melted by the heating resistor 21 provided so as to surround the ink tank 20, and passes through the ink supply path 24. The ink is supplied to the inkjet head 11.

FIG. 4 is a schematic configuration diagram for explaining the ink jet head 11. As shown in FIG. As shown in FIG.
The inkjet head 11 includes a nozzle 12, a pressure chamber 13, a piezoelectric element 14 that pressurizes ink in the pressure chamber 13,
It is composed of a common ink chamber 15, an ink supply port 15a, a heating resistor 21a for heating and maintaining the temperature of the molten ink 22, and an electrode 21b. The molten ink 22 supplied to the pressure chamber 13 from the common ink chamber 15 is kept at a temperature optimum for ink ejection by the heating resistor 21 a in the pressure chamber 13, and is ejected from the nozzle 12 by driving the piezoelectric element 14. You. Then, the jetted molten ink 22
After being attached to the intermediate transfer member 28, the image is transferred to the master 2,
Fixing is completed by penetrating into the master 2 and solidifying.

The above-described ink jet head 11
Has been described using an example in which an electromechanical transducer such as a piezoelectric element is used. However, the same effect can be obtained by using other pressing means such as a wire-type pressing mechanism. As the heating means, a heating means such as a ceramic heater can be used in addition to the heating resistor. The temperature of the molten ink 22 in the ink tank 20 may not be as high as the temperature of the ink in the pressure chamber 13 immediately before ejection. For this reason, the heating resistor 21 provided outside the ink tank 20 and the heating resistor 21a provided outside the pressure chamber 13 may be individually heated to suppress a rise in temperature in the ink jet recording apparatus.

On the other hand, when the ink tank 20 and the inkjet head 11 are heated to the same temperature, the heating method is as follows.
May be individually heated by the heating resistors 21 and 21a as described above. However, a method in which the ink tank 20 and the inkjet head 11 are covered in a single housing by a heating mechanism incorporating a nichrome wire or the like may be adopted. Good.

The heating temperature of the head of the ink jet recording apparatus is set in the range of 80 to 150 ° C., preferably 90 to 130 ° C.

As the recording head, it is desirable to use a recording head which can make full use of a technique using solid ink and has a high resolution.

For example, when a solid ink is supplied to the ink tank 20 of the ink jet recording apparatus shown in FIG. 3 and plate making is performed at a head heating temperature of 120 ° C., a piezoelectric element driving voltage of 70 V, and an ink viscosity at the time of jetting of 20 cps, a 40 μm nozzle is used. A sharp image can be formed at a resolution of 600 dpi by ejecting ink particles of 60 μm.

The ink image 36 on the surface of the intermediate transfer member 28 is cooled down to the intermediate state of the rollable solid as the intermediate transfer member 28 rotates, and enters the intermediate transfer portion 37 sandwiched between the roller 32 and the intermediate transfer member 28. Go. The ink image 36 is deformed to a final image state by applying pressure, and is transferred to the surface of the master 2. Thus, the ink image 36 is transferred to the master 2 by the pressure received from the elastic body surface of the roller 32.

As described above, on the lithographic printing original plate,
The master 2 obtained by forming an image by the solid jet method is provided as an offset planographic printing plate.

[0101]

EXAMPLES The present invention will be described in detail with reference to examples below, but the contents of the present invention are not limited to these examples.

Example 1 and Comparative Examples A to D <Preparation of a lithographic printing plate precursor> A composition having the following contents was added together with glass beads to a paint shaker (Toyo Seiki Co., Ltd.)
And dispersed for 60 minutes, and then the glass beads were separated by filtration to obtain a dispersion.

A 10% aqueous solution of gelatin 94 g Silica: Sylysia 430 (manufactured by Fuji Silysia Chemical Ltd.) 21.9 g Average particle size: 2.5 μm Colloidal silica 20% solution: Snowtec C (manufactured by Nissan Chemical Industries, Ltd.) 90g mean particle diameter:: 10 to 20 nm fluorinated alkyl esters FC430 (3M Co.) 0.24 g hardening _{compound: K-1 1.20g CH 2 =} CHSO 2 CH 2 CONH (CH 2) 3 NHCOCH 2 SO 2 = CH = CH ₂ water 65g

A support of ELP-I type master (trade name, manufactured by Fuji Photo Film Co., Ltd.) used as an electrophotographic planographic printing plate for light printing (Beck smoothness of under layer side: 500 (second / 10 cc) )), The composition was applied thereon using a wire bar, and dried at 100 ° C. for 10 minutes to form an image receiving layer having a coating amount of 8 g / m ² .
A lithographic printing original plate was obtained.

Comparative Example A In the same manner as in Example 1 except that 33.9 g of Thylithia 430 alone was used instead of Thylithia 430 and Snowtech C in the composition of the image receiving layer of Example 1 described above. A lithographic printing original plate was prepared.

<Comparative Example B> In the image receiving layer composition of Example 1, thyricia 430 and Snowtech C were used.
Was used in the same manner as in Example 1 except that only Snowtech C was used in an amount of 33.9 g (as a solid content).

<Comparative Example C> In Example 1, a dispersion was prepared using the following composition instead of the image receiving layer composition, and coated and dried in the same manner as in Example 1 to obtain a lithographic printing plate precursor. It was created. However, drying was performed at 130 ° C. for 10 minutes.

Polyvinyl alcohol: 10% aqueous solution of PVA-117 (manufactured by Kuraray Co., Ltd.) 94 g Silica: Thylysia 430 21.9 g Colloidal silica 20% solution: Snowtec C 90 g 80% aqueous solution of melamine formaldehyde resin 1.2 g ammonium chloride 10% aqueous solution 1.1 g of water 55 g

<Comparative Example D> In Example 1, a dispersion was prepared using the following composition instead of the image-receiving layer composition, and then coated and dried in the same manner as in Example 1 to prepare a lithographic printing plate precursor. It was created. However, drying was performed at 130 ° C. for 10 minutes.

Polyvinyl alcohol: 10% aqueous solution of PVA-117 (manufactured by Kuraray Co., Ltd.) 90 g Silica: Syloid 308 (particle diameter 7 μm) (manufactured by Fuji Devison Chemical Co., Ltd.) 30 g Colloidal silica 20% solution: 150 g of Snowtec C 50% aqueous dispersion of kaolin clay 30 g 80% aqueous solution of melamine formaldehyde resin 1.2 g 10% aqueous solution of ammonium chloride 1.0 g water 38 g

The film properties (surface smoothness), surface wettability (contact angle with water), film strength, and plate making properties of these original plate for lithographic printing were examined.

Further, when these plate-making plates are used as offset printing plates, the printability (ground stain, printing durability, etc.)
Was examined.

Table 1 shows the above results.

[0114]

[Table 1]

The evaluation items shown in Table 1 are as follows.

Note 1) Smoothness of image receiving layer: A lithographic printing original plate was measured using a Beck smoothness tester (manufactured by Kumagaya Riko Co., Ltd.).
The smoothness (second / 10c) under the condition of air volume 10cc
c) was measured.

Note 2) Surface wettability 2 μl of distilled water was placed on the surface of the lithographic printing plate precursor, and the surface contact angle (degree) after 30 seconds was measured with a surface contact meter (CA-D, manufactured by Kyowa Interface Science Co., Ltd.). (Trade name). The lower the value, the better the wettability to water and the more hydrophilic.

Note 3) Mechanical strength of the surface layer: The surface of the lithographic printing plate precursor was emery paper with a load of 50 g / cm ² using Haydon-14 type surface test material (manufactured by Shinkatsu Chemical Co., Ltd.). Abrasion powder was repeatedly removed 1000 times with (# 1000), and the residual film ratio (%) was determined from the weight loss of the surface layer and determined as mechanical strength.

Note 4) Plate making quality: Phaser 340JS printer (Sony-T) which is commercially available as a solid jet printer for forming an image on a recording medium via an intermediate transfer member
Using ektronix Co., Ltd.) and black solid ink (Instec Black: accessory to the printer), a lithographic printing original plate was prepared.

The above printer conforms to the configuration shown in FIGS. 2 to 4. The black solid ink contains a wax having a melting point of about 100 ° C., and is heated at a temperature of about 120 ° C. to melt the ink. The viscosity was about 20 cps.
The material of the intermediate transfer drum is anodized aluminum, and its Bekk smoothness is 3000 seconds / 10
cc or more. The temperature of the intermediate transfer section was 50 ° C.

The image quality of the copied image of the plate-making product thus obtained was visually evaluated using a 20-fold loupe.

Note 5) Print image quality: After making a lithographic printing plate precursor in the same manner as in Note 4), a fully automatic printing machine (AM-
2850 (trade name, manufactured by Am Co., Ltd.), a PS plate treating agent: EU-3 (manufactured by Fuji Photo Film Co., Ltd.) diluted 50-fold with distilled water as a fountain solution, The plate was placed in a fountain solution tray, and printed using a black ink for offset printing and passed through a plate to a printing machine. The print image (ground fog, solid uniformity of the image portion) of the tenth printed material is 2
Visual evaluation was performed using a 0x loupe.

Note 6) Printing durability Printing was carried out in the same manner as in the above Note 5), and the number of printed sheets until the background stain or missing image of the printed matter could be visually discriminated was examined.

As shown in Table 1, the image receiving layer of each original plate provided on the same support had almost the same smoothness in each of the plates of Example 1 and Comparative Examples C and D, and the synthetic silica fine powder was used. Comparative Example A using only A has slightly lower smoothness,
Comparative Example B using only colloidal silica as a pigment was a plate having high smoothness.

When the wettability of the surface layer was measured by the contact angle with water, all the plates had low values and high hydrophilicity.

Further, when the film strength of the surface layer was examined, Example 1 and Comparative Example D showed high values and were good. But,
Compared with Example 1, the film strength of Comparative Example C using PVA and a preferable crosslinking agent (water resistance) as the binder was significantly reduced. In Comparative Example A using only synthetic silica powder as the inorganic pigment, the film strength was significantly reduced, and Comparative Example B using only colloidal silica was further deteriorated.

Next, each original plate was actually made, and the image quality of the plate was examined by visual observation. As a result, Comparative Examples B and C of the present invention were obtained.
Plates D and D had good plate making quality and printing quality. That is, the plate-making product of the present invention obtained by forming an image by ejecting ink from a printer has no thin lines, no loss of fine characters, a solid portion is uniform, no unevenness is recognized at all, and even a non-image portion, No ink adhesion was observed.

On the other hand, in Comparative Example A, thin lines, thin characters were missing, and white spots were uneven in solid portions.

Next, this plate-making product was used as a printing plate, and the performance of the printing plate was evaluated. Only the printing plate according to the present invention had an image free from fine lines, missing fine characters, and uniform solid portions. And provided more than 1,000 good prints without ink stains on non-image areas.

On the other hand, in Comparative Example A, in the printed image from the printed material, thin lines in the image area, missing fine characters, and uneven white spots in the solid area were conspicuous.

In Comparative Examples B, C and D, the image quality of the printed matter was the same as in Example 1, and the printed images were good without any problem. However, the printing ink adhered to the non-image area was stained on any of the plates, and this became a practical problem. Further, in Example B, the image receiving layer itself suffered film loss on about 100 sheets after printing. Comparative Example C was about 300 sheets after printing, and Comparative Example D was 2 sheets.
At about 00 sheets, the image portions were missing.

From these results, it was found that the physical properties of the image receiving layer and the image quality in plate making and printing depend on the type of other inorganic pigment, hydrophilic resin and waterproofing agent to be combined with synthetic silica fine powder particles having a particle size of 1 to 6 μm. It is thought that there is a close relationship with the performance. In other words, the film using only the synthetic silica particles and the colloidal silica ultrafine particles used alone as the inorganic particles has insufficient film strength, and the contact angle with water on the surface is almost the same, but the actual printed matter is less likely to have print ink adhesion stains. This was likely to occur and the hydrophilicity was insufficient. Further, when a conventionally known PVA was used as the binder resin, the film strength was lower than that of the present invention, and the hydrophilicity necessary for eliminating ink stains during printing could not be obtained.

Further, in addition to using PVA, a clay is used in combination with a pigment as described in JP-B-5-178.
The image receiving layer having the same contents as the embodiment described in the specification of No. 71 had the same film strength and plate making quality as those of the present invention, but lacked hydrophilicity in printing.

Further, in Comparative Examples C and D, even if the image was sufficiently fixed by the printer, the adhesion to the image receiving layer was not sufficient, and the image portion was missing after about 200 to 300 prints. .

From these facts, it is possible to obtain a large number of prints of which only the original plate of the present invention is good.

Examples 2-3 and Comparative Example E [Preparation of Water-Resistant Support] Fine paper weighing 100 g / m ² was used as a substrate, and a back layer coating composition having the following composition was coated on one surface of the substrate with a wire bar. Coating using, dry application amount 12g /
After the m ² back layer was provided, calender processing was performed so that the smoothness of the back layer was about 50 (second / 10 cc).

<Coating for Backcoat Layer> 200 parts kaolin (50% aqueous dispersion) 60 parts polyvinyl alcohol aqueous solution (10%) 60 parts SBR latex (solid content 50%, Tg 0 ° C.) 100 parts Melamine resin (solid 80%, Sumiretz Resin SR-613) 5 parts

Next, a coating for an under layer having the following composition was applied to the other surface of the substrate using a wire bar, and an under layer having a dry coating amount of 10 g / m ² was provided. The calendar processing was performed so that the value was about 2 as shown in FIG.

<Coating for Under Layer> 60 g clay (50% aqueous dispersion) 36 g SBR latex (solid content 50%, Tg 25 ° C.) 4 g melamine resin (solid content 80%, Sumirez Resin SR-613) 4 g 105g of water

As shown in Table 2, each of the three types of water-resistant supports thus obtained was designated as support sample No. 01 ~
No. 03.

[0141]

[Table 2]

[Preparation of lithographic printing original plate] 01-No. An image-receiving layer was provided on the dispersion No. 03 so that the applied amount of the dispersion liquid after drying was 6 g / m ² after drying. The smoothness of the surface of each master is 200 to 230 (seconds /
10 cc), and the contact angle with water was 5 degrees or less. The film strength of each of the surface layers was 96 to 97%.

<Application of Image Receiving Layer> The composition described below was put together with glass beads in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) and dispersed for 60 minutes. Obtained.

A 10% aqueous solution of gelatin 100 g Silica: Sylysia 310 (manufactured by Fuji Silysia Chemical Ltd.) 22 g Average particle size: 1.4 μm Alumina sol 520 (manufactured by Nissan Chemical Industry Co., Ltd.) 90 g Average particle size: 10 to 20 nm Hydrogenated alkyl ester FC430 0.3 g Hardening compound: K-2 1.5 g CH ₂ ＣＨCHSO ₂ (CH ₂ ) ₂ O (CH ₂ ) ₂ O (CH ₂ ) ₂ SO ₂ CH ＝ CH ₂ water 70 g

Using each of the lithographic printing original plates prepared as described above, a plate was made through a printer in the same manner as in Example 1, and then a printing machine was used using an Oliver 94 type (manufactured by Sakurai Seisakusho Co., Ltd.) as a printing machine. As a water, a solution obtained by diluting SLM-0D (manufactured by Mitsubishi Paper Mills) 10 times with distilled water is put into a fountain solution tray portion, and printing is performed through a plate using a black printing ink for offset printing using a printing machine. went.

The quality of the drawn image of the plate-making product thus obtained was evaluated as follows. Table 3 shows the results.

[0147]

[Table 3]

The evaluation items shown in Table 3 are as follows.

Note 7) Image quality of plate making The drawing image of the plate made was observed and evaluated by an optical microscope at a magnification of 20 times. In the table, ◎, ◎, and × are shown.

◎ There is no problem in the drawn image at all, and the fine lines and fine characters are very good. ○ There is no problem in the drawn image, and the fine lines and fine characters are good.

Note 8) Printed Image The image of the obtained printed matter was evaluated in the same manner as in the above-described plate making image quality.

Note 9) Printing durability The number of sheets printed until the background stain or missing image of the printed matter could be visually discriminated was examined.

As shown in Table 3, the surface smoothness of the image receiving layer is almost the same, but the smoothness of the support is 150 (sec / 10
When the print quality was as low as cc), the image quality of the plate-making was deteriorated, and even after printing, the image was damaged from the start of printing. On the other hand, the plate of the present invention was improved as the smoothness was increased, and the printing durability was 1,000 sheets or more.

This means that the smoothness of the support immediately below the image receiving layer greatly affects the unevenness of the surface of the image receiving layer, and when the unevenness of the image receiving layer overlaps, there is a region where the flatness is greatly degraded. However, it is considered that image loss occurs at that portion.

That is, the higher the smoothness of the underlayer of the support directly under the image receiving layer, the better the quality of plate making and printing.

Examples 4-5 and Comparative Examples FG Preparation of Water-Resistant Support Ethylene-methyl acrylate-acrylic acid copolymer (molar ratio: 65:30) was coated on both sides of a high-quality paper weighing 95 g / m ^2. : 5) The aqueous latex of 5) was applied and dried such that the dry coating amount was 0.2 g / m ^2, and the density was 0.920 g / cc and the melt index was 5.
70% of low density polyethylene with 0g / 10min, density 0.95
0 g / cc, 1.5 g of high-density polyethylene of 8.0 g / 10 min with a melt index of 15 g, and 15% of conductive carbon were laminated and extruded at a thickness of 25 μm by extrusion using pellets obtained by roasting and kneading. A layer (surface resistivity 6 × 10 ⁹ Ω) was provided. Next, the smoothness was adjusted to 2000 (seconds / 10 cc) by calendering.

Further, the other surface of the substrate was coated using a coating wire bar for a back coat layer having the following composition, and a back coat layer having a dry coating amount of 20 g / m ² (surface resistivity: 8 × 10 ⁷⁾
Ω), calendering was performed by setting calendar conditions so that the smoothness of the back coat layer was 450 (seconds / 10 cc).

<Coating for Backcoat Layer> 200 parts by weight of clay (50% aqueous dispersion) 40 parts by weight of oxidized starch (20% aqueous solution) 150 parts by weight of SBR latex (solid content 49%, Tg10 ° C.) 150 parts by weight Melamine Resin initial condensate 10 parts by weight (solid content 80%, Sumiretz Resin SR-613)

Next, the surface of the polyethylene layer was
A corona discharge treatment was performed under the conditions of sec / m ² , and an image receiving layer was provided thereon as described below to prepare a lithographic printing original plate.

<Preparation of Lithographic Printing Precursor> A composition having the following contents was put together with glass beads into a paint shaker (manufactured by Toyo Seiki Co., Ltd.), and the smoothness of the surface layer was adjusted to the value shown in Table 4. After adjusting the dispersion time, the glass beads were separated by filtration to obtain each dispersion.

A 10% aqueous solution of gelatin 100 g Silica: thyristia 310 25 g Colloidal silica: Snowtech C 100 g Sodium dodecylbenzenesulfonate 2.0 g Hardening compound: K-3 2.2 g CH ₂ ＣＨCH—CONH (CH ₂ ) _{2 N (CH 2) 2 NHCOCH} = CH 2 water 65g

The above composition was coated on the water-resistant support using a wire bar, and dried at 110 ° C. for 20 minutes to form an image receiving layer having a coating amount of 6 g / m _2. A lithographic printing original plate was obtained.

[0163]

[Table 4]

As shown in Table 4, on the water-resistant support having the same high-smoothness underlayer, the image-receiving layers composed of the same components were prepared by changing the smoothness. In Comparative Example F having a value of 15 (sec / 10 cc), a remarkably poor result was obtained.

When printing was further performed, a high smoothness of 600
In Comparative Example G (seconds / 10 cc), the image portion was missing about 500 sheets after printing.

As described above, only when the surface smoothness of the image receiving layer of the present invention is within the predetermined range, good plate making quality, printing quality and printing durability are exhibited.

Examples 6 to 12 A lithographic printing plate precursor was prepared in the same manner as in Example 4 except that the compounds shown in Table 5 below were used in place of the gelatin-hardenable compound (K-3). did. The Beck smoothness of the surface of each obtained plate was 50 to 180 (sec / 10 cc).
Was in the range. The contact angle of the surface with water was 5 degrees or less.

[0168]

[Table 5]

As shown in Table 5, the film strength of the image receiving layer of each plate was 95% or more, indicating a sufficient film strength.

This printing original plate was prepared in the same manner as in Example 1.
The plate was made, desensitized, and subjected to offset printing as a printing plate.

The obtained printed matter had clear image quality with no stain on the non-image area in the same manner as in Example 1. More than 1,000 such products were obtained, and both the printed image and the printing durability were excellent. I understood that.

Example 11 The procedure of Example 4 was repeated, except that 20 g (as solid content) of colloidal silica (Snowtec C) was replaced by 15 g (as solid content) of a 5% aqueous solution of titanium oxide sol. To prepare a lithographic printing original plate.

The Beck smoothness of the surface layer is 210 (sec / 10
cc), the contact angle of the surface with water was 5 degrees or less, and the film strength of the surface layer was 95%.

Plate making was performed in the same manner as in Example 1, and a printing plate was used for offset printing.

The obtained printed matter was of a clear image quality with no stain on the non-image area, similarly to the printing plate of Example 1.
The printing durability was as good as 1,000 sheets or more.

[0176]

According to the present invention, a printing plate having a clear image and excellent printing durability can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus system used in the present invention.

FIG. 2 is a schematic configuration diagram illustrating a main part of an inkjet recording apparatus used in the present invention.

FIG. 3 is a schematic configuration diagram showing a head section of an ink jet recording apparatus used in the present invention.

FIG. 4 is a schematic configuration diagram for explaining an ink jet head of a head section of the ink jet recording apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording apparatus 2 Master 3 Computer 4 Pass 10 Head part 11 Ink jet head 12 Nozzle 13 Pressure chamber 14 Piezoelectric element 15 Common ink port 15a Ink supply chamber 20 Ink tank 21, 21a Heating resistor 21b Electrode 22 Melt ink 23 Tank cap 24 Ink supply path 25 Solid ink 28 Intermediate transfer member 29 Heater 30 Master guide 31 Heater 32 Roller 33 Core part 34 Heater 36 Ink image

Claims (6)

[Claims] Claims: 1. An ink composition which is solid at room temperature is melted by heat.
An image was formed on the intermediate transfer member by ejecting droplets of the ink in the hot-melt state from a nozzle, and an image receiving layer mainly composed of an inorganic pigment and a hydrophilic binder resin was provided on the water-resistant support. A method for forming a lithographic printing plate by forming an image by a hot-melt ink jet method in which an image of the intermediate transfer body is formed by contact transfer on an image receiving layer of a direct-drawing lithographic printing plate precursor, The receiving layer uses, as the inorganic pigment, silica particles having an average particle diameter of 1 to 6 μm and ultrafine colloidal inorganic pigment particles having an average particle diameter of 10 to 50 nm in a weight ratio of 40 to 70 to 60 to 30. Gelatin was used as the hydrophilic binder resin in a weight ratio of the inorganic pigment to gelatin in the range of 85 to 40 to 15 to 60, and the image-receiving layer containing these was cured by a gelatin-curable compound. Endurance Ink jet plate making printing plate creation method, which is a sex. 2. The smoothness of the surface of the image receiving layer of the lithographic printing plate precursor is 30 to 500 (sec / 10 cc) in Beck smoothness.
The method for producing an ink-jet type plate-making printing plate according to claim 1, wherein 3. The smoothness of the surface of the support adjacent to the image receiving layer is 300 (sec / 10 cc) in Beck's smoothness.
The method for producing an ink-jet type plate-making printing plate according to claim 1 or 2. 4. An average particle size of 1 contained in the image receiving layer.
The method for producing an ink-jet type plate-making printing plate according to any one of claims 1 to 3, wherein the colloidal inorganic pigment ultrafine particles of 0 to 50 nm are colloidal silica, alumina sol or titanium oxide ultrafine particles. 5. The gelatin-curable compound contained in the image receiving layer is a compound containing two or more double bond groups represented by the following general formula (I) in a molecule.
The method for producing an ink-jet type plate-making printing plate according to any one of the above. In the general formula _{(I) CH 2 = CH-} X- formula (I), _{X, -OSO 2 -, - SO 2} -, - CON
R- or an -SO ₂ NR-. (However, R represents a hydrogen atom or an aliphatic group having 1 to 8 carbon atoms.) 6. The ink composition contains a wax having a melting point of 50 to 150 ° C., a resin, a coloring material, and an adhesion modifier, and becomes a hot-melt liquid by heating to 80 ° C. or higher. The method for producing an ink-jet type plate making plate according to any one of claims 1 to 5, wherein the viscosity of the hot-melt liquid is 1 to 20 cps or more.