JP2007261248A - Medium to be recorded, lithographic printing plate using it, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium to be recorded for lithographic printing plate capable of preventing bleeding of ink, leaving no significant stains during printing and affording an image obtained by curing ink with good printing durability when ink droplets are injected on the recording medium to be recorded for lithographic printing plate and a lithographic printing plate excellent in printing durability, capable of forming a high-resolution image, using the recording medium to be recorded. <P>SOLUTION: The recording medium to be recorded for lithographic printing plate is provided with a hydrophilic layer and an ink receiving layer laminated in this order, wherein the ink receiving layer contains one or more compounds selected from the group consisting of compounds having a fluoroalkyl group and compounds having a dimethyl siloxane skeleton and receives ink injected by an ink jet recording system. The ink receiving layer preferably contains 0.2-50.0 mg/m<SP>2</SP>of one or more compounds selected from the group consisting of compounds having a fluoroalkyl group and compounds having a dimethyl siloxane skeleton, and 1-200 mg/m<SP>2</SP>of hydrophilic resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording medium used in image formation by an ink jet recording method, a lithographic printing plate obtained by a combination of the recording medium and a radiation curable ink, and a method for producing a lithographic printing plate by an ink jet recording method. Is.

  As a recording method for forming an image on a recording medium based on an image data signal, there are an electrophotographic method, a thermal transfer method, an ink jet method, and the like. The electrophotographic system requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposure, which complicates the system and becomes an expensive apparatus. The thermal transfer method is inexpensive, but uses an ink ribbon, so the ink ribbon that has not been used for transfer becomes a waste material, and the running cost is high. On the other hand, the inkjet method is an excellent recording method because it is an inexpensive device and ejects ink only to a required image portion to directly form an image on a recording medium, so there is no waste material and the running cost is low.

The recording medium used for the ink jet recording system is selected according to the purpose of use, such as paper, plastic, and metal. For example, printed matter can be obtained directly by recording on plain paper such as high-quality paper or recycled paper. However, since the inkjet recording has a low recording speed, it takes a lot of time to obtain a large number of printed materials. Therefore, an attempt has been made to prepare a printing plate by ink jet recording and obtain a large number of printed materials using the prepared printing plate. For example, as a lithographic printing plate for drawing an image using an ink jet method, an aluminum support that has been previously hydrophilized with a hydrophilic organic polymer compound has been proposed (for example, see Patent Document 1). However, there is a problem that ink ejected by ink jet spreads on the substrate.
On the other hand, a method for preparing a lithographic printing plate by causing a specific ink to act on a support surface-treated with a terminal alkyl, silicon-based or fluorine-based surfactant is disclosed (for example, see Patent Documents 2 to 7). .) In addition, it is described that if the contact angle of the ejected ink to the support is 20 ° or more, the ink hardly spreads (for example, see Patent Document 8). However, with these methods, the smearing of the ejected ink is suppressed, but stains are likely to occur during printing, the strength of the image area formed by the ink and the adhesion to the support are not sufficient, and There is a problem that printability is inferior.
JP 2000-108537 A US Pat. No. 6,472,045 US Pat. No. 6,455,132 US Pat. No. 6,451,413 US Pat. No. 6,555,205 US Pat. No. 6,471,359 US Pat. No. 6,742,886 JP 2000-43439 A

An object of the present invention is to provide a recording medium for a lithographic printing plate that suppresses ink bleeding when ink is ejected, has no problem of contamination during printing, and provides better printing durability. is there.
A further object of the present invention is to provide a lithographic printing plate using the recording medium of the present invention, which has excellent resolution and printing durability of the image area, and prevents stains on the non-image area of the obtained printed matter, and The object is to provide a simple method for producing a lithographic printing plate.

As a result of intensive studies, the present inventors have confirmed that both the ink bleeding and the non-image area contamination can be suppressed by reducing the contact angle with the droplet ejection ink and the contact angle with water. The inventors have found that the above-mentioned problems can be solved by using a recording medium having an ink-receiving layer and a hydrophilic layer suitable for the heading, and the present invention has been completed.
That is, the recording medium of the present invention contains, on a support, one or more compounds selected from the group consisting of a hydrophilic layer, a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton, An ink receiving layer for receiving ink ejected by an ink jet recording method is sequentially laminated.
A region where ink is not ejected by the ink jet recording method of the ink receiving layer is removed after the ink ejection and ink curing processes, for example, by dampening water during printing or by gum in the gumming process. In the partial area, the hydrophilic layer is preferably exposed.

The support used for the recording medium preferably has a grain structure in which a medium wave structure with an average opening diameter of 0.5 to 5 μm and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed. , Having a grain shape on the surface with a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm Is more preferable.
In this case, the average of the ratio of the depth to the opening diameter of the small wave structure is preferably 0.2 or more.

The lithographic printing plate according to claim 8 of the present invention comprises, on a support, at least one compound selected from the group consisting of a hydrophilic layer, a compound having a fluoroalkyl group, and a compound having a dimethylsiloxane skeleton. A lithographic plate obtained by depositing ink on a surface of a recording medium containing an ink receiving layer that contains ink and receiving ink ejected by an ink jet recording method, and curing the ink to form an image area. It is a print version.
Here, the contact angle between the ink receiving layer formed on the hydrophilic layer and water is smaller than 10 °, and the contact angle between the ink receiving layer and ink ejected by inkjet is larger than 30 °. In view of improving the image quality, the contact angle between the ink receiving layer and the fountain solution used during printing is also preferably smaller than 10 °.

The method for producing a lithographic printing plate according to claim 11 of the present invention includes a step of ejecting ink onto the surface of the ink receiving layer of the recording medium of the present invention described above by an ink jet recording method, a step of curing the ink, and And a step of removing the ink receiving layer other than the area where the ink is ejected, which is performed thereafter.
The step of removing the ink receiving layer other than the region where the ink has been ejected may be performed with dampening water during printing, or may be performed with gum in the gum treatment step.

The recording medium of the present invention has a hydrophilic layer and an ink receiving layer containing at least one compound selected from the group consisting of a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton.
By introducing into the ink receiving layer a compound having a fluoroalkyl group that lowers the surface energy of the ink or a compound having a polydimethylsilyloxy group, the contact angle between the ink receiving layer surface and the ink is 30 °. The image area can be made larger, the ink bleeding is suppressed, the resolution is high, and the adhesiveness with the ink receiving layer is excellent.
On the other hand, it is necessary to expose the hydrophilic layer except for the ink receiving layer in order to make the non-image area difficult to be stained during printing. For this reason, it is necessary to design the ink receiving layer in the non-image area where no ink is present after ink ejection and curing to be easily removed with fountain solution or gum to expose the adjacent hydrophilic layer. In this way, in order to easily remove the ink receiving layer, the contact angle between the ink receiving layer and water should be smaller than 10 °. That is, it is preferable to introduce a hydrophilic resin into the ink receiving layer or introduce a compound having a fluoroalkyl group or a compound having a polydimethylsilyloxy group in a water-soluble state. More preferably, a compound having a fluoroalkyl group or a compound having a polydimethylsilyloxy group is made water-soluble and blended with a hydrophilic resin. Thus, the hydrophilic layer surface that appears when the ink receiving layer is removed has high wettability with water and dampening water used during printing, and the occurrence of non-image stains is effectively suppressed. .
Usually, the ink-receiving layer is easily wetted by water, and further, when it dissolves in water, the printing durability is lowered.In one embodiment of the present invention, a radiation polymerization type ink is used to improve the film quality of the image area. In addition, a water-resistant resin film is formed in the ink adhesion area after radiation curing, and high printing durability is realized. Also, by using a polymer-dissolving ink that is another preferred embodiment of the present invention, a water-resistant resin film is formed, and similarly high printing durability is realized. Furthermore, in a preferred embodiment of the present invention, the surface shape of the support is controlled in order to further improve the adhesion between the ink and the support. In this way, it was possible to obtain a recording medium suitable for a direct-drawing lithographic printing plate that was able to suppress ink bleeding, was not soiled during printing, and exhibited high printing durability.
In addition, the contact angle in the invention is the contact angle of the air droplet, and is a value 10 seconds after the 0.8 μL dropping.

According to the present invention, it is possible to provide a recording medium for a lithographic printing plate that suppresses ink bleeding when the ink is ejected, has no problem of contamination during printing, and provides better printing durability. it can.
Furthermore, according to the present invention, a lithographic printing plate using the recording medium of the present invention, which has excellent resolution and printing durability of the image area and in which stains on the non-image area of the obtained printed matter are suppressed, and the lithographic plate A simple method for producing a printing plate can be provided.

Hereinafter, the present invention will be described in detail.
First, the recording medium of the present invention will be described. The recording medium of the present invention contains, on a support, one or more compounds selected from the group consisting of a hydrophilic layer, a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton, and inkjet recording. An ink receiving layer for receiving radiation-polymerized ink ejected by the method is sequentially laminated.

[Support]
The support used in the recording medium of the present invention is not particularly limited as long as it is a dimensionally stable plate having necessary strength and durability. For example, paper, plastic (for example, polyethylene) Paper, metal plates (eg, aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, nitric acid) Cellulose, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), metal laminated or vapor-deposited paper, or plastic film.

  Among them, in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. In the present invention, a surface-treated aluminum support is preferred. These are described below.

<Aluminum support>
Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

Such an aluminum plate may be subjected to surface treatment such as roughening treatment or anodizing treatment, if necessary. Hereinafter, such a surface treatment will be briefly described.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

<Details of surface treatment for producing aluminum grain shape>
The support according to the present invention is such that the above-described surface grain shape is formed on the surface of the aluminum plate by subjecting the aluminum plate to be described later to surface treatment. The support according to the present invention is obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment, but the production process of this support is not particularly limited, and various types other than the surface roughening treatment and the anodizing treatment are performed. These steps may be included. As a typical method for forming the above-mentioned surface grain shape, an aluminum plate is successively subjected to a mechanical surface roughening treatment, an alkali etching treatment, an acid desmutting treatment, and an electrochemical surface roughening treatment using an electrolytic solution. Method, mechanical roughening treatment on aluminum plate, alkali etching treatment, desmutting treatment with acid and electrochemical roughening treatment using different electrolytes multiple times, alkali etching treatment on aluminum plate with acid A method of sequentially performing desmutting treatment and electrochemical surface roughening treatment using an electrolytic solution, a method of subjecting an aluminum plate to alkali etching treatment, desmutting treatment with acid, and electrochemical surface roughening treatment using different electrolytic solutions multiple times However, the present invention is not limited to these.
In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed. As described above, the support for a lithographic printing plate of the present invention obtained by these methods has a structure in which irregularities of two or more different periods are superimposed on the surface, and is a planographic printing plate. Excellent stain resistance and printing durability. Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
The mechanical roughening treatment is effective as a roughening treatment means because it can form an uneven surface with an average wavelength of 5 to 100 μm at a lower cost than the electrochemical roughening treatment. is there. Examples of the mechanical surface-roughening treatment method include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used. A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in Japanese Patent Application No. -55871 and Japanese Patent Application No. 4-204235 (Japanese Patent Laid-Open No. 6-024168) characterized in that the surface is elastic is also applicable.

  In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of repeatedly transferring using a transfer roll etched with fine irregularities, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, etc. may be used. it can. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded. Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed. In addition, as the mechanical surface roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used. In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably performed before the electrochemical surface roughening treatment.

Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated. The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is carried out by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used. When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumicestone, silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable.
In particular, silica sand is preferable in terms of excellent roughening efficiency because it is harder and less likely to break than Pamiston. The average particle diameter of the abrasive is preferably 3 to 50 μm, and more preferably 6 to 45 μm in terms of excellent surface roughening efficiency and a narrow graining pitch. For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.

  As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in JP-B-50-40047 can be exemplified.

<Electrochemical roughening treatment>
In the electrochemical surface roughening treatment, an electrolytic solution used for the electrochemical surface roughening treatment using a normal alternating current can be used. Among these, a characteristic uneven structure can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid. As the electrolytic surface roughening treatment in the present invention, it is preferable to perform the first and second electrolytic treatments with an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated, so that the surface state is made uniform, and uniform electrolytic surface roughening is possible during subsequent electrolysis with alternating waveform current. . This electrolytic surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

  Various electrolyzers and power sources have been proposed. U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used. Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53- Nos. 149135 and 54-146234 can be used.

  As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600, 482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 can also be used.

  The concentration of the acidic solution is preferably 0.5 to 2.5% by mass, but it is particularly preferably 0.7 to 2.0% by mass in consideration of use in the smut removal treatment. Moreover, it is preferable that liquid temperature is 20-80 degreeC, and it is more preferable that it is 30-60 degreeC.

  An aqueous solution mainly composed of hydrochloric acid or nitric acid is an aqueous solution of hydrochloric acid or nitric acid having a concentration of 1 to 100 g / L, such as nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate, or aluminum chloride, sodium chloride, ammonium chloride, etc. At least one of the hydrochloric acid compounds having hydrochloric acid ions can be used by adding in a range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid or nitric acid as a main component. Preferably, a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of hydrochloric acid or nitric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L is preferably used.

  Further, by adding and using a compound capable of forming a complex with Cu, uniform graining is possible even for an aluminum plate containing a large amount of Cu. Examples of the compound capable of forming a complex with Cu include ammonia; hydrogen atom of ammonia such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, cyclohexylamine, triethanolamine, triisopropanolamine, EDTA (ethylenediaminetetraacetic acid). And amines obtained by substituting with a hydrocarbon group (aliphatic, aromatic, etc.); metal carbonates such as sodium carbonate, potassium carbonate, potassium hydrogen carbonate and the like. In addition, ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, and ammonium carbonate are also included. The temperature is preferably 10-60 ° C, more preferably 20-50 ° C.

  The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable. A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 1 to 3 msec. If it is less than 1 msec, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate are likely to occur. When TP exceeds 3 msec, especially when a nitric acid electrolyte is used, it is easily affected by trace components in the electrolyte typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is performed. It becomes hard to be broken. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

  A duty ratio of trapezoidal wave alternating current of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum, a duty is used. A ratio of 1: 1 is preferred. A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. When the frequency is lower than 50 Hz, the carbon electrode of the main electrode is easily dissolved, and when the frequency is higher than 70 Hz, it is easily affected by an inductance component on the power supply circuit, and the power supply cost is increased.

  One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 3, the current ratio between the AC anode and cathode applied to the aluminum plate facing the main electrode is controlled to achieve uniform graining and to dissolve the carbon of the main electrode. In addition, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 is a main electrolytic cell, and 50 is an auxiliary anode cell. An anodic reaction that acts on the aluminum plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.

  As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

(Nitric acid electrolysis)
Pits having an average opening diameter of 0.5 to 5 μm can be formed by electrochemical surface roughening using an electrolytic solution mainly composed of nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm are also generated. To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably from ^{1~1000C / dm 2, 50~300C / dm} 2 It is more preferable that The current density at this time is preferably ²⁰ to 100 A / dm ² . Further, when a high concentration or high temperature nitric acid electrolytic solution is used, a small wave structure having an average opening diameter of 0.2 μm or less can be formed.

(Hydrochloric acid electrolysis)
Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface with only slight electrolysis. These fine irregularities have an average opening diameter of 0.01 to 0.2 μm and are uniformly generated on the entire surface of the aluminum plate. Such grained total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed in order to obtain the, is preferably from 1~100C / dm ^2, in 20~70C / dm ² More preferably. The current density at this time is preferably ²⁰ to 50 A / dm ² .

In such an electrochemical surface roughening treatment using an electrolytic solution mainly composed of hydrochloric acid, a large crater-like swell is simultaneously formed by increasing the total amount of electricity involved in the anode reaction to 400 to 1000 C / dm ^2. In this case, fine irregularities having an average opening diameter of 0.01 to 0.4 μm are formed on the entire surface by being superimposed on a crater-like wave having an average opening diameter of 10 to 30 μm.

The aluminum plate is preferably subjected to cathodic electrolysis treatment during the first and second electrolytic surface-roughening treatments performed in the electrolytic solution such as nitric acid and hydrochloric acid. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic surface roughening treatment. This cathodic electrolysis treatment is carried out in an acidic solution at a cathode electric quantity of preferably 3 to 80 C / dm ² , more preferably 5 to 30 C / dm ² . If the amount of cathodic electricity is less than 3 C / dm ² , the amount of smut adhesion may be insufficient, and if it exceeds 80 C / dm ² , the amount of smut adhesion may be excessive. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening processes.

<Alkaline etching treatment>
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.

  Alkaline etching performed before the electrolytic surface roughening treatment removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) if mechanical surface roughening treatment is not performed. If the surface of the unevenness generated by the mechanical surface roughening treatment is dissolved, the surface with sharp undulations is smoothed. It is done for the purpose of changing.

If you do not mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 0.1 to 10 g / ^{m 2,} and more preferably 1 to 5 g / ^{m 2.} If the etching amount is less than 0.1 g / m ² , rolling oil, dirt, natural oxide film, etc. may remain on the surface, so that uniform pits cannot be generated in the subsequent electrolytic surface roughening treatment, resulting in unevenness. May occur. On the other hand, when the etching amount is 1 to 10 g / m ² , the surface rolling oil, dirt, natural oxide film, and the like are sufficiently removed. An etching amount exceeding the above range is economically disadvantageous.

When performing mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 3 to 20 g / ^{m 2,} and more preferably 5 to 15 g / ^{m 2.} If the etching amount is less than 3 g / m ² , unevenness formed by mechanical surface roughening may not be smoothed, and uniform pit formation may not be possible in subsequent electrolytic treatment. In addition, the stain may deteriorate during printing. On the other hand, when the etching amount exceeds 20 g / m ² , the concavo-convex structure may disappear.

The alkali etching treatment performed immediately after the electrolytic surface roughening treatment is performed for the purpose of dissolving the smut generated in the acidic electrolytic solution and dissolving the edge portion of the pit formed by the electrolytic surface roughening treatment. . Since the pits formed by the electrolytic surface roughening treatment are different depending on the type of the electrolytic solution, the optimum etching amount is also different, but the etching amount of the alkali etching treatment performed after the electrolytic surface roughening treatment is 0.1 to 5 g / m. ² is preferred. When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used. When the electrolytic surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of alkali metal salts include alkali metal silicates such as sodium silicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

  Although the density | concentration of an alkaline solution can be determined according to the etching amount, it is preferable that it is 1-50 mass%, and it is more preferable that it is 10-35 mass%. When aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90 ° C. The treatment time is preferably 1 to 120 seconds.

  Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.

<Desmut treatment>
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. The desmut treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include, for example, a method of passing the aluminum plate through a bath containing the acidic solution, a method of immersing the aluminum plate in a bath containing the acidic solution, and an acidic solution containing aluminum. The method of spraying on the surface of a board is mentioned. In the desmutting treatment, the acidic solution is mainly composed of an aqueous solution mainly composed of nitric acid or an aqueous solution mainly composed of hydrochloric acid discharged in the above-described electrolytic surface-roughening treatment, or sulfuric acid discharged in an anodic oxidation process described later. It is possible to use a waste solution of an aqueous solution. The liquid temperature in the desmut treatment is preferably 25 to 90 ° C. The processing time is preferably 1 to 180 seconds. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.
The aluminum plate roughened as described above is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodizing treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. If the amount of the anodic oxide film is less than 2.0 g / m ² , the non-image portion of the planographic printing plate is likely to be scratched, and so-called “scratch stain” in which ink adheres to the scratch portion during printing tends to occur.

A hydrophilic layer is formed on the surface of the support described above, and the support according to the present invention includes a layer having surface hydrophilicity.
[Hydrophilic layer]
The hydrophilic layer on the support may be formed by subjecting the anodized film on the support surface to a hydrophilic treatment, and is formed by separately applying a hydrophilic layer on the support surface by a coating method or a dipping method. May be.
Hereinafter, the hydrophilization of the support surface will be described.
<Hydrophilic surface and hydrophilization>
As the hydrophilic surface, an anodic oxide film may be used, but it is preferable to further perform a hydrophilic treatment thereon. The hydrophilic surface as used herein means a surface having a contact angle with water of less than 10 °, and a surface of less than 5 ° is particularly preferable. Moreover, it is preferable that the hydrophilic compound is adsorbed on the anodized film when the hydrophilic treatment is performed.
Examples of the hydrophilization treatment include treatment with potassium fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of the molecular compound and a divalent metal include immersion treatment in such polyvalent sulfonic acid compound Tamol.

  Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids. Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

Moreover, it is preferable to perform the hydrophilic treatment by a method of immersing in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate.
Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures. Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like. The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

As the Si adhesion amount, 1.0 to 20.0 mg / m ² is desirably adhered. 2.0 to 17.0 mg / m ² is more desirable. When it is 1.0 mg / m ² or more, the stain resistance is good, and when it is 20.0 mg / m ² or less, printing durability and burning printing durability are good.

The coating amount was calculated by determining the amount of specific atoms (m / m ² ) by a calibration curve method using a fluorescent X-ray analyzer, for example. Using an RIX3000 manufactured by Rigaku Corporation as a fluorescent X-ray analyzer, the amount of atoms was measured from the peak height.

<Washing treatment>
It is preferable to perform water washing after the completion of the above-described processes. For washing, pure water, well water, tap water, or the like can be used. A nip device may be used to prevent the processing liquid from being brought into the next process.

(Ink receiving layer)
The recording medium for a lithographic printing plate of the present invention has an ink receiving layer on the surface of the hydrophilic layer of a support having a hydrophilic layer. As the ink receiving layer, in order to suppress ink bleeding, one or more compounds selected from the group consisting of an organic fluorine compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton (hereinafter referred to as a specific water-repellent compound as appropriate) It is a layer containing. When an ink receiving layer containing a specific water-repellent compound is provided, using it together with a hydrophilic resin gives the ink receiving layer removability with dampening water, etc., and as a result effectively suppresses the occurrence of stains in non-image areas. This is preferable because it is possible.

Hereinafter, the specific water repellent compound will be described.
<Organic fluorine compound having fluoroalkyl group>
A preferred fluorine-based compound that can be used in the present invention is a compound represented by the general formula R _F -Rpol.
In the above general formula, R _F represents a linear or branched fluoroalkyl group having 3 or more carbon atoms, and Rpol represents carboxylic acid or a salt thereof, sulfonic acid or a salt thereof, phosphoric acid or a salt thereof, phosphonic acid or a salt thereof. A polar group such as a salt, an amino group or a salt thereof, a quaternary ammonium salt, a polyethyleneoxy skeleton, a polypropyleneoxy skeleton, a sulfonamide group, an ether group, or a betaine structure is represented. Among these, those having a sulfoxyl group or a salt structure thereof are preferable because they are less likely to interact with silicate and have good removability.
In addition, it is particularly preferable that R _F has a C _n F _{2n + 1} C _m H _2m COO— skeleton from the viewpoint of suppressing ink bleeding, and has two or more C _n F _{2n + 1} C _m H _2m COO— skeletons in one molecule. More preferred. Here, n is an integer of 2 or more, and m is an integer of 1 or more.
Specific examples [(F-1) to (F-19)] of fluorine-based compounds preferably used in the present invention are listed below, but the present invention is not limited thereto.

Moreover, you may use a high molecular fluorine-type compound as a fluorine-type compound which concerns on this invention. In particular, those having a surfactant action and water-soluble are preferred.
Specific examples of the polymeric fluorosurfactant include a copolymer of an acrylate having a fluoroaliphatic group or a methacrylate having a fluoroaliphatic group and a poly (oxyalkylene) acrylate or poly (oxyalkylene) methacrylate. It is done. In the copolymer, the monomer unit of acrylate or methacrylate having a fluoroaliphatic group is preferably 7 to 60% by mass based on the mass of the copolymer, and the molecular weight of the copolymer is 3000 to 100,000. Is appropriate.

  The fluoroaliphatic group may be linear or branched and preferably contains 40% by mass or more of fluorine. Specific examples of the acrylate or methacrylate having the fluoroaliphatic group include N-butylperfluorooctanesulfonamidoethyl acrylate, N-propylperfluorooctanesulfonamidoethyl acrylate, and methylperfluorooctanesulfonamidoethyl acrylate. The molecular weight of the polyoxyalkylene group in the poly (oxyalkylene) acrylate or methacrylate is preferably 200 to 3000. Examples of the oxyalkylene group include oxyethylene, oxypropylene, and oxybutylene groups, preferably oxyethylene and oxypropylene groups. For example, acrylate or methacrylate having 8 to 15 moles of oxyethylene group added is used. Moreover, foamability can be suppressed by adding a dimethylsiloxane group etc. to the terminal of this polyoxyalkylene group as needed.

The fluorosurfactants as described above can be generally obtained on the market, and commercially available products can also be used in the present invention. Two or more fluorosurfactants can be used in combination.
As products sold, Asahi Glass Co., Ltd., Surflon S-111, S-112, S-113, S-121, S-131, S-141, S-145, S-381, S-382 , Dainippon Ink & Chemicals, Inc. MegaFuck F-110, F120, F-142D, F-150, F-171, F177, F781, Sumitomo 3M Fluorad FC-93, FC-95, FC -98, FC-129, FC135, FX-161, FC170C, FC-171, FC176, Bayer Japan K.K. FT-248, FT-448, FT-548, FT-624, FT-718, FT-738 Etc. (above, trade name).

Other specific water-repellent compounds that can be used in the present invention include compounds having a dimethylsiloxane skeleton, and specifically include the following compounds.
<Polydimethylsiloxane compound>
Examples of the polydimethylsiloxane compound include silicon surfactants. Water-soluble ones are particularly preferable from the viewpoint of removability. Examples thereof include dimethylsiloxane methyl (polyoxyethylene) copolymer, dimethylsiloxane methyl (polyoxypropylene) copolymer, and dimethylsiloxane methyl (orioxyethylene / polyoxypropylene) copolymer.

-Combination with hydrophilic resin-
One or more compounds selected from these organic fluorine compounds and compounds having a dimethylsiloxane skeleton and a hydrophilic resin can be blended to form an ink receiving layer.
In the formation of the ink-receiving layer, the use of these specific water-repellent compounds and a hydrophilic resin can further improve the stain resistance and the ink bleeding suppression.
Preferably 50 mg / ^{m 2} or less as a coating amount of the specific water-repellent compound in the case constituting the ink-receiving layer, more preferably in the range of 0.5 to 10 mg / ^{m 2.} Preferably 50 mg / ^{m 2} or less as a coating amount of the compound having a dimethylsiloxane skeleton, more preferably in the range of 0.5 to 10 mg / ^{m 2.}
The coating amount of the hydrophilic resin is preferably 200 mg / ^{m 2} or less, more preferably in the range of 1~170mg / ^{m 2,} particularly preferably in the range of 50 to 150 mg / ^{m 2.} By using a hydrophilic resin together with the water repellent compound in the ink receiving layer, the ink repellency in the non-image area other than the ink droplet deposition area forming the image area is improved, and it becomes more effective for the stain prevention effect.

  The hydrophilic resin that can be used here is not particularly limited as long as it is a water-soluble resin, but in particular, a water-soluble cellulose (for example, carboxymethyl cellulose) having a carboxylic acid or a salt thereof, an acrylic or methacrylic polymer or a copolymer thereof, a sulfonic acid. Acrylic, methacrylic, vinyl, styrenic hydrophilic resin having a group or a salt thereof, a hydrophilic resin having an amide group such as polyacrylamide or polyvinylpyrrolidone, a hydrophilic resin having an amino group, a hydrophilic resin having phosphoric acid or a salt thereof Examples thereof also include phosphate-modified starch described in JP-A No. 62-097892.

<Formation of ink receiving layer>
This organic ink receiving layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the organic compound in an organic solvent or a mixed solvent thereof to adsorb the compound, and then washed with water and dried to provide an organic undercoat layer. .
In the former method (coating method), a solution of the organic compound having a concentration of 0.005 to 10% by mass can be applied by various methods. In the latter method (immersion method), the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, and the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C. The immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute.
As a method for forming the ink receiving layer, it is preferable to use a coating method from the viewpoint of suppressing the adsorption to the substrate and improving the anti-staining effect during printing.

Thus, the recording medium for the lithographic printing plate of the present invention can be obtained by laminating and forming the hydrophilic layer and the ink receiving layer on the support. This ink receiving layer is suitably used for receiving ink that is ejected by the ink jet recording method.
Next, a planographic printing plate of the present invention using this recording medium will be described.
[Lithographic printing plate]
The lithographic printing plate of the present invention can be obtained by forming an image area on the surface of the recording medium of the present invention by ejecting ink in an image-like manner and curing the ink. Curing as used herein means solidifying the ejected ink solution, and includes a method of volatilizing the solvent in the ink and a method of polymerizing and curing the radiation polymerization type ink. From the viewpoint of the strength of the image area of the lithographic printing plate formed by curing the ink, as the ink, ink that is polymerized and cured by radiation is ejected in an image-like manner, irradiated with radiation (mainly ultraviolet rays), It is preferable to take the form of hardening.
The radiation curable ink composition that is suitably used for forming the lithographic printing plate of the present invention will be described.

<Radiation polymerization ink>
The radiation curable ink suitably used in the present invention can be prepared by, for example, a known method described in “Latest UV Curing Practical Handbook” (published on February 25, 2005) issued by the Technical Information Association, Inc. As a main component, a polymerizable compound such as a polymerization initiator, a polymerizable monomer or an oligomer is contained.
There are two types of polymerization, radical polymerization type and ion polymerization type such as cationic polymerization, both of which can be suitably used in the present invention. In the present invention, since the support needs to have a water contact angle of less than 10 °, it is preferable to use a non-aqueous ink composition from the viewpoint of preventing ink droplets from bleeding.

(Polymerization initiator)
In the present invention, examples of the polymerization initiator that can be suitably used include known radical polymerization or cationic polymerization photopolymerization initiators used in radiation-curable ink compositions. The other photopolymerization initiator that can be used in combination with the present invention causes a chemical change through the action of light or interaction with the electronically excited state of the sensitizing dye, and is at least one of a radical, an acid, and a base. A compound that produces one species.
As the specific photopolymerization initiator, those known to those skilled in the art can be used without limitation. Preferred photopolymerization initiators include aromatic ketones, benzoin derivatives such as benzoin and benzoin ether, onium salts such as sulfonium salts and iodonium salts, organic peroxides, hexaarylbiimidazole compounds, ketoxime esters, and borate salts. , Azinium compounds, metallocene compounds, compounds having a carbon-halogen bond, and the like. These compounds mainly have an ability of initiating polymerization with respect to ultraviolet rays, but they can also be spectrally sensitized to visible light and infrared rays in combination with an appropriate sensitizer.
The preferable content of the polymerization initiator in the ink composition is in the range of 0.01 to 30% by mass, preferably 0.1 to 20% by mass.

(Polymerizable compound)
In the present invention, examples of the polymerizable monomer or oligomer suitably used include known radical polymerizable or cationic polymerizable monomers or oligomers. Monomers or oligomers used include (meth) acrylates, (meth) acrylamides, (meth) acrylic acid, maleic acid and derivatives thereof, styrenes, olefins, vinyl ethers, vinyl esters, epoxy compounds, oxetane compounds And cyclic esters. In order to control the mechanical properties of the formed image, in the present invention, these compounds can be used in combination with a monofunctional compound having one polymerizable functional group in the molecule and a polyfunctional compound having two or more.
The preferable content of the polymerizable compound in the ink composition is in the range of 10 to 99% by mass, preferably 30 to 95% by mass.

(Other additives)
In addition to the polymerization initiator and polymerizable compound, various known additives can be used in combination with the radiation curable ink composition depending on the purpose.
The ink is preferably colored for the visibility of the image. A known dye or pigment can be used for coloring.
In addition, a surfactant for improving ejection properties, a polymerization inhibitor for stability during storage of ink, and the like can be added. Furthermore, various polymers can be added to improve the mechanical properties of the formed image. Specifically, (meth) acrylic polymer, polyurethane resin, polyamide resin, polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polypropylene glycol, Shellac resins, vinyl resins, rubber resins, waxes, and other natural resins can be used.

In the present invention, from the viewpoint of improving the ink bleeding suppression effect, it is preferable to contain a fluorine compound having a fluoroalkyl group and a silicon compound having a polydimethylsiloxane skeleton as contained in the ink receiving layer.
At this time, the ink receiving layer of the support does not need to contain a component that suppresses ink bleeding and may or may not contain the component. The fluorine-based compound having a fluoroalkyl group may be 0.05% to 5% by weight or less, particularly preferably 0.2 to 3% by weight in the ink composition.

  In the present invention, an ink containing no solvent may be used as described above, but an ink mixed with water or an organic solvent can also be used. Examples of organic solvents to be mixed include ketone solvents such as acetone and methyl ethyl ketone, methanol, ethanol, propanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, dipropylene glycol, diethylene glycol monoethyl ether, tripropylene glycol, and tripropylene. Alcohol solvents such as glycol monomethyl ether, aromatic solvents such as toluene, ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, ethyl lactate, γ-butyrolactone, tetrahydrofuran, diethylene glycol diethyl ether, diethylene glycol diethyl ether, tripropylene Glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monoethyl Ether solvents such as ether, propylene glycol n-butyl ether, dipropylene glycol dimethyl ether, 3-methoxy 1-butanol, propylene glycol methyl ether acetate, propylene glycol dimethyl ether, and hydrocarbon solvents such as Isopar G (manufactured by Exxon). It is done.

<Ink with polymer dissolved in organic solvent>
In the present invention, as the ink for forming the image portion of the lithographic printing plate, in addition to the radiation polymerization type ink, an ink in which a polymer is dissolved in an organic solvent (hereinafter, appropriately referred to as a polymer dissolution type ink) can be used. . As the polymer suitably used for the polymer-soluble ink composition, a polymer or copolymer having an acidic group is preferable. Examples of acidic groups include carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups, with carboxylic acid groups being particularly preferred.
As the polymer or copolymer, those obtained by polymerization of unsaturated double bonds are preferred, and acrylic or methacrylic polymers are preferred. As the monomer having an acidic group, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, 2-acrylamido-2-methyl-1-propanesulfonic acid, and styrenesulfonic acid are preferable.

The monomer having an acid group may be copolymerized with another monomer, and examples of the copolymerizable monomer include acrylic acid ester, methacrylic acid ester, styrene monomer, vinyl monomer, acrylonitrile and the like.
These polymers preferably have a weight average molecular weight of 3000 to 200000. These polymers in the ink component can be added in an addition amount of 2 to 50% by mass.
As a solvent used in this type of ink composition, a compound having at least one hydroxyl group, ether group or ester group in one molecule is preferable. Specifically, diethylene glycol diethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol nbutyl ether, dipropylene glycol dimethyl ether, 3-methoxy 1-butanol, propylene glycol methyl ether acetate, ethanol , Propanol, ethylene glycol, propylene glycol, diethylene glycol and the like.
As other components of the ink composition, colorants such as pigments and dyes and surface tension modifiers such as surfactants can be added depending on the purpose.
In the polymer-dissolved ink, after droplet ejection, the solvent is evaporated and removed, whereby the polymer is cured and an image portion is formed.
In the direct drawing lithographic printing plate of the present invention, the image area may be formed using any of these inks.

<Formation of image portion of planographic printing plate>
(1. Inkjet drawing)
Here, the radiation curable ink composition is ejected onto the surface of the recording medium of the present invention by an ink jet recording method.
The ink jet recording method that can be used here includes a continuous method in which ink droplets for recording and non-recording are separated by an electric field or the like after ink droplets are continuously ejected, and ink droplets necessary for recording. There is an on-demand system in which only the nozzle is discharged.
The on-demand method includes a thermal method (bubble method) in which ink droplets are ejected by a bubble pressure generated by rapidly heating ink, and a piezo method using a piezo element (piezoelectric element). The piezo method is classified into a direct mode type and a share mode type depending on a difference in the direction of occurrence of distortion with respect to an applied voltage. In addition, the on-demand method includes an electrostatic method in which electric charges are applied to ink or particles contained in the ink and electrostatic discharge control is performed, and a solid inkjet method in which solid ink is heated and melted and discharged. There is also. For details of the ink jet recording method, see “Inkjet Printer Technology and Materials” published by CMC Co., Ltd. (published July 31, 1998), and “Recent inkjet technology know-how” published by Technical Information Association Co., Ltd. (June 2005). However, in the present invention, any method can be suitably used without limitation.

(2. Curing of ink)
When the radiation curable ink composition which is a preferred embodiment of the ink composition used for forming the lithographic printing plate of the present invention is used, the ink is cured by irradiating with radiation after ink droplet ejection.
As a means for curing the ink that has landed on the recording medium, a commonly used mercury lamp, metal halide lamp, or the like may be used, or a light source such as a light emitting diode, a semiconductor laser, or a fluorescent lamp may be used. Further, a hot cathode tube, a cold cathode tube, an electron beam, an X-ray, or the like, a light source in which an ink polymerization reaction proceeds, an electromagnetic wave, or the like can be used.
When using a metal halide lamp, it is preferable to use a lamp with a brightness of 10 to 1000 W / cm and an illuminance of 1 mW / cm ^{2 to} 100 W / cm ^{2 on} the surface of the recording medium.
The exposure energy is preferably 0.1 mJ / cm ^{2 to} 100 J / cm ² . In addition, in a mercury lamp, a metal halide lamp, or the like that uses high-pressure discharge, ozone is generated with discharge, and thus it is preferable to have an exhaust means. The exhaust means is preferably arranged so as to also collect ink mist generated during ink ejection.

In the case of curing by radical polymerization, since the polymerization is inhibited by oxygen, it can be cured with low energy by exposure in a low oxygen concentration state, that is, in a gas atmosphere such as nitrogen. When energy such as light for curing is applied to the ink discharge nozzle, the ink mist adhering to the surface of the nozzle may solidify, which may hinder ink discharge. In order to keep it to a minimum, it is preferable to take measures such as shading. Specifically, it is preferable to provide a partition that prevents the nozzle plate from being irradiated, or to provide a means for limiting the incident angle to the medium so as to reduce stray light.
In addition, when a solvent-soluble ink that is another preferred embodiment is used, the ink is cured by removing the solvent by drying. If desired, a known method such as heating can be applied to promote ink curing after ink ejection.
Specific examples of the curing method include a method of volatilizing the solvent by blowing air, a method of volatilizing the solvent by heat, and a combination thereof. As a method using air blowing, a method using air of 15 ° C. or higher is particularly preferable. In the method of curing by blowing air, it is particularly preferable to blow air of 25 ° C. or higher, and more preferably 35 ° C. or higher. Examples of the method for volatilizing the solvent by heat include a method of heating in an oven. In this drying method, it is preferable to heat and dry in an oven at 50 ° C to 100 ° C. Of course, air may be sent at this time to help volatilize the solvent.

(3. Fixing and gumming)
As described above, the drawn image can be cured and fixed by radiation as described in the radiation polymerization type ink. Further, gum treatment mainly containing gum arabic, starch derivatives, surfactants and the like can be performed between fixing and printing. The gum is described in JP-B-62-16834, JP-A-62-225118, JP-A-63-52600, JP-A-62-7595, JP-A-62-11693, and JP-A-62-83194. Those are preferred. In the gumming process, the ink receiving layer is preferably dissolved and removed with a gum solution. The plate thus obtained can be subjected to normal printing by a lithographic printing machine.
Of the ink-receiving layer, those containing a hydrophilic resin and those containing a water-soluble organic fluorine-based compound should be removed with the gum used in this gum treatment in the ink non-droplet area (non-image area). Can do.

In this way, the lithographic printing plate on which the image area is formed by curing the radiation-polymerized ink applied in an image-like manner is subjected to a printing process by supplying ink and fountain solution.
General-purpose fountain solution and ink used for printing with the lithographic printing plate of the present invention can be used, and lithographic printing machines can also be used for printing.

<Dampening water>
As the fountain solution, a Dahlglen system using an aqueous solution containing about 20 to 25% isopropyl alcohol as the fountain solution has been proposed and widely used. In addition, isopropyl alcohol has a peculiar unpleasant odor and has problems in toxicity, and is an organic solvent poisoning prevention rule (organic law) type 2 organic solvent, which is subject to regulation, so it replaces isopropyl alcohol In addition, a technology using a non-volatile or high boiling point compound as an alternative to isopropyl alcohol has been developed. In addition, for example, those containing a specific alkylene oxide nonionic surfactant in a dampening water composition, those containing an alkylenediamine ethylene oxide and propylene oxide adduct in a dampening water composition, etc. Any of these has been proposed and can be used for printing using the planographic printing plate of the present invention.

  As for the fountain solution in which the above-described technology for replacing isopropyl alcohol is introduced, for example, JP-A-5-92677, JP-A-5-318958, JP-A-2001-287476, and JP-A-2-269909. JP-A-3-63187, JP-A-3-90389, JP-A-3-90390, JP-A-4-363297, JP-A-5-112085, JP-A-11-78281, Japanese Laid-Open Patent Publication Nos. 11-105449, 2001-130164, 2001-138659, 2001-180146, 2001-18553, 2001-71658, 2002 JP-A-187375, JP-A-2002-187376, and JP-A-2002-19 For example, JP-A-51-72507 discloses an alkylenediamine which is described in detail in JP-A-853 and includes a specific alkylene oxide nonionic surfactant in a fountain solution composition. What includes ethylene oxide and propylene oxide adducts in the fountain solution composition is described in detail, for example, in JP-A-2002-254852, and these fountain solutions are also used in the lithographic printing plate of the present invention. Applicable to printing.

  In the recording medium of the present invention, the ink receiving layer containing a hydrophilic resin, the one using a water-soluble organic fluorine-based compound, and the like, the ink receiving layer in the ink non-droplet area (non-image area) is By being easily removed by these fountain solutions during printing and exposing the hydrophilic surface, it is possible to effectively suppress stains on the non-image area.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these.
[Examples 1 to 104, Comparative Examples 1 to 5]
(Production of support)
<Aluminum plate>
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.005 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: Containing 0.03% by mass, the balance is prepared using Al and an inevitable impurity aluminum alloy, and after performing the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing using a continuous annealing machine at 500 degreeC, it finished by cold rolling to 0.24 mm in thickness, and obtained the aluminum plate of JIS1050 material. After making this aluminum plate width 1030mm, it used for the surface treatment shown below.

<Surface treatment>
(Surface treatment 1)
In the surface treatment, the following various treatments (b) to (j) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(B) Alkali etching treatment The aluminum plate obtained above is subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. / M ^{2 was} dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, water washing by spraying was performed.

(E) Alkali etching treatment The aluminum plate was sodium hydroxide concentration of 26 wt%, performed at 32 ° C. to etching treatment by spraying with an aluminum ion concentration of 6.5 wt% aqueous solution, the aluminum plate 0.25 g / ^{m 2} was dissolved, Removes the smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening treatment was performed using alternating current in the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Alkali etching treatment An aluminum plate was sprayed using an aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C., and the aluminum plate was dissolved at 0.10 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having the structure shown in FIG. 4 to obtain a lithographic printing plate support of Example 1. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

(Surface treatment 2 and 3)
Above in (h), except that dissolved amount of the aluminum plate to respectively 0.2 g / ^{m 2} and 0.5 g / ^{m 2} are in the same manner as surface treatment 1, surface treatment 2 and 3 of the lithographic printing plate A support was obtained.

(Surface treatment 4)
A support for a lithographic printing plate having a surface treatment 4 was obtained in the same manner as in the surface treatment 1 except that the frequency of the AC voltage was 30 Hz in the above (g) and the above (h) was not performed.

(Surface treatment 5 and 6)
In the above (g), lithographic printing plate supports of surface treatments 5 and 6 were obtained in the same manner as in the surface treatment 1 except that the frequency of the AC voltage was 300 Hz and 500 Hz, respectively.

(Surface treatment 7)
A lithographic printing plate support of surface treatment 7 was obtained in the same manner as in surface treatment 1 except that the current density was 15 A / dm ^{2 in} terms of the current peak value in (d) above.

(Surface treatment 8)
In the above (d), a lithographic printing plate support of surface treatment 8 was obtained in the same manner as in surface treatment 1 except that the temperature of the electrolytic solution was 70 ° C.

(Surface treatment 9)
A lithographic printing plate support with surface treatment 9 was obtained in the same manner as in surface treatment 1 except that the following (a) was performed before (b).
(A) Mechanical surface roughening treatment Using an apparatus as shown in FIG. 1, a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water is supplied as a polishing slurry to the surface of the aluminum plate. However, a mechanical surface roughening treatment was performed with a rotating roller-like nylon brush. In FIG. 1, 1 is an aluminum plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers. The average particle size of the abrasive was 40 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(Surface Treatment 10: Surface Treatment 1 for Comparative Example)
In the above (g), a lithographic printing plate support of the surface treatment 10 was obtained by the same method as the surface treatment 3 except that the frequency of the alternating voltage was 10 Hz.

(Surface treatment 11: Surface treatment 2 for comparative example)
In the above (g), the surface treatment was carried out in the same manner as in the surface treatment 1 except that the frequency of the alternating voltage was 10 Hz and the amount of dissolution of the aluminum plate was 1.0 g / m ² in the above (h). 11 lithographic printing plate supports were obtained.

(Surface treatment 12: Surface treatment 3 for comparative example)
In the above (d), a lithographic printing plate support of surface treatment 12 was obtained by the same method as surface treatment 1 except that the frequency of the AC voltage was 15 Hz.

(Surface Treatment 13: Surface Treatment 4 for Comparative Example)
A lithographic printing plate support with surface treatment 13 was obtained in the same manner as in Example 1 except that in (d) above, the temperature of the electrolytic solution was 80 ° C. and TP was 0 msec.

(Surface treatment 14: Surface treatment 5 for comparative example)
In the above (g), the surface treatment was carried out in the same manner as in the surface treatment 8 except that the frequency of the AC voltage was 10 Hz and the amount of dissolution of the aluminum plate was 1.0 g / m ² in the above (h). 14 lithographic printing plate supports were obtained.

(Surface Treatment 15: Comparative Surface Treatment 6)
A lithographic printing plate support having a surface treatment 15 was obtained in the same manner as in the surface treatment 1 except that (g), (h) and (i) were not performed.

(Surface Treatment 16: Surface Treatment 7 for Comparative Example)
A lithographic printing plate support having a surface treatment 16 was obtained in the same manner as in the surface treatment 1 except that (d), (e), and (f) were not performed.

(Surface Treatment 17: Surface Treatment 8 for Comparative Example)
In the above (g), the surface treatment 17 was treated in the same manner as in the surface treatment 1 except that a mixed solution of hydrochloric acid and acetic acid (hydrochloric acid concentration 7.5 g / L, acetic acid concentration 15 g / L) was used as the electrolytic solution. A support for a lithographic printing plate was obtained.

2. Measurement of surface shape of lithographic printing plate support The following measurements (1) to (4) were performed on the concave portions on the surface of the lithographic printing plate support obtained above. The results are shown in Table 1. In Table 1, “-” indicates that there was no concave portion of the corresponding wavelength.

(1) Average opening diameter of medium wave structure The surface of the support was photographed at a magnification of 2000 times from directly above using an SEM. 50 medium pits) were extracted, and the diameter was read to obtain the opening diameter, and the average opening diameter was calculated.

(2) Average aperture diameter of the small wave structure The surface of the support was photographed at a magnification of 50000 times from directly above using a high resolution SEM, and 50 small wave structure pits (small wave pits) were extracted from the obtained SEM photograph. The diameter was read and used as the opening diameter, and the average opening diameter was calculated.

(3) Average ratio of depth to aperture diameter of wavelet structure The average ratio of depth to aperture diameter of wavelet structure is obtained by photographing the fracture surface of the support at a magnification of 50000 times using a high-resolution SEM. In the SEM photograph, 20 small wave pits having an opening diameter of 0.3 μm or less were extracted, the opening diameter and the depth were read, the ratio was obtained, and the average value was calculated.

(4) Average wavelength of large-wave structure Two-dimensional roughness measurement is performed with a stylus type roughness meter (SUFCOM 575, manufactured by Tokyo Seimitsu Co., Ltd.), and the average peak interval Sm defined in ISO 4287 is measured five times. Was defined as the average wavelength. Two-dimensional roughness measurement was performed under the following conditions. cut off 0.8, tilt correction FLAT-ML, measurement length 3 mm, longitudinal magnification 10000 times, scanning speed 0.3 mm / sec, stylus tip diameter 2 μm

<Formation of hydrophilic layer>
Each of the lithographic printing plate supports obtained above was subjected to a hydrophilic treatment.
(Hydrophilic treatment with polyvinylphosphonic acid compound: hydrophilic layers 1 to 3)
The support was immersed in an aqueous polyvinylphosphonic acid solution having a concentration shown in Table 2, and then washed with water and dried.
(Hydrophilic treatment with silicate: hydrophilic layers 4 to 6)
The support was immersed in a No. 3 sodium silicate aqueous solution having a concentration shown in Table 2, and then washed and dried with water.
(Hydrophilic treatment with potassium fluoride zirconate: hydrophilic layers 7 to 9)
The support was immersed in a fluorinated zirconic acid aqueous solution having a concentration shown in Table 2, and then washed and dried.
(Hydrophilic treatment with tamol: hydrophilic layers 10 to 12)
The support was immersed in an aqueous solution of tamol having the concentration shown in the table, and then washed and dried.

<Formation of ink receiving layer>
The ink receiving layer coating solution having the composition described in Table 3 below was applied with a wire bar and dried at 80 ° C. for 15 seconds to form a coating film. The coating amount after drying was carried out by adjusting the wet amount of the wire bar.

  The fluorine compounds and hydrophilic resins used in each coating solution composition are as shown in Tables 4 to 5 below.

Details of the compounds used in Tables 4 and 5 are as follows.
Si-1 (water-soluble silicon surfactant); Sun Silicon M-84 (water-soluble silicon surfactant, dimethylsiloxane ethylene oxide copolymer, Sanyo Chemical Industries product)
Hydrophilic resin:
(A) Poly (2-acrylamido-2-methyl-1-propanesulfonic acid)
(B) Carboxymethylcellulose potassium salt (C) The following structural formula

A recording medium was prepared by combining the above support, surface treatment, hydrophilization treatment, and ink receiving layer, and a lithographic printing plate was produced by ejecting ink onto the surface and curing.
<Ink added with fluorosurfactant>
The radical polymerization UV ink manufactured by Mimaki Co., Ltd. is referred to as Ink 1.
Ink 2 was prepared by adding 0.5% of Megafac F780 (Dainippon Ink Co., Ltd.) to the above-mentioned radical polymerization UV ink manufactured by Mimaki.
<Ink with polymer dissolved in organic solvent>
Ink 3 was prepared by dissolving 10 g of methyl methacrylate-methacrylic acid copolymer (copolymerization ratio; methyl methacrylate 60 mol% / methacrylic acid 40 mol%, weight average molecular weight 6000) in 90 g of diethylene glycol diethyl ether.
<Ink in which UV ink is diluted with organic solvent>
Ink 4 was prepared by dissolving 20 g of the above-mentioned radical polymerization UV ink manufactured by Mimaki Co., Ltd. in 80 g of diethylene glycol diethyl ether.

<Ink droplet ejection by inkjet recording method>
The ultraviolet polymerization curable ink 1 was ejected onto the lithographic printing plate precursors 1 to 94 using UJF-605C manufactured by MIMAKI ENGINEERING CO., LTD. Equipped with a piezo-type head and an ultraviolet irradiation device. Cured.

<Performance evaluation of planographic printing plates>
(1. Printing durability evaluation)
The obtained lithographic printing plate was fountained with IF102 (Fuji Photo Film Co., Ltd.) Dainippon Ink & Chemicals, Inc. DIC-GEOS (N) black ink using a Lislon printing machine manufactured by Komori Corporation. The printing durability was evaluated based on the number of printed sheets when it was visually recognized that the density of the solid image started to decrease.
(2. Evaluation of resistance to dirt)
The dampening solution was printed with a 3% aqueous solution of Ecology-2 (manufactured by Fuji Photo Film Co., Ltd.) and DIC-GEOS (s) red ink on a Mitsubishi Diamond F2 printer (manufactured by Mitsubishi Heavy Industries). After the watering roller was brought into contact with the 10-turn plate, printing was started at the same time as ink was applied, and the number of sheets required until a beautiful printed material was obtained was read.

  First, using the surface-treated 9 support hydrophilized by hydrophilization treatment 5, the ink receiving layers shown in Table 6 and Table 7 were formed on the surface, and Examples 1 to 34 and Comparative Examples 1 to 5 were formed. A lithographic printing plate was prepared and evaluated by the method described above. Except for Comparative Example 4, the ink receiving layer in the non-ink-dropped region could be removed with dampening water, and the hydrophilic surface was exposed.

  From the results shown in Tables 6 and 7, when the ink contact angle is larger than 30 ° and the water contact angle is smaller than 10 °, the dot diameter is small and the number of developed images is 20 or less. It turns out that it has sex. On the other hand, when the ink contact angle is smaller than 30 °, the dot diameter exceeds 100 μm, and when the water contact angle exceeds 15 °, the number of developed images increases.

Next, using a recording medium in which the hydrophilic layer described in Table 8 and Table 9 below is formed on the surface of the support that has been subjected to the surface treatment 1, and the ink receiving layer 15 is formed on the surface. Examples 35-47
A lithographic printing plate was prepared and evaluated in the same manner. The results are shown in Table 8. Moreover, using the recording medium formed with the ink receiving layer 31, lithographic printing plates of Examples 48 to 60 were produced and evaluated in the same manner. The results are shown in Table 9.

  From the results of Tables 8 and 9, it can be seen that when the anodized film is subjected to a hydrophilic treatment, the water contact angle is lowered and the number of developed images is lowered.

  Next, the lithographic plates of Examples 61 to 77 using the recording medium on which the surface of the aluminum support subjected to the surface treatment described in Tables 10 and 11 was subjected to the hydrophilic treatment 3 and the ink receiving layer 15 was formed. A printing plate was prepared and evaluated in the same manner. The results are shown in Table 10. Further, after performing the same hydrophilic treatment, lithographic printing plates of Examples 78 to 94 were prepared using the recording medium on which the ink receiving layer 31 was formed, and evaluated in the same manner. The results are shown in Table 11.

  Next, the surface of the support 9 that has been hydrophilized by hydrophilization 5 is used, and the ink receiving layer shown in Table 12 is formed on the surface. Ink 3 and ink 4, which are type inks, were ejected using a piezo-type head, a piezo-type head, and UJF-605C manufactured by Mimaki Engineering Co., Ltd. In addition, when hitting, ultraviolet irradiation is not performed, and after jetting, air of 35 ° C. is blown for 20 seconds with a dryer, and the ink is dried and cured to produce lithographic printing plates of Examples 95 to 104. Evaluated. The results are shown in Table 12 below. The results of Examples 25 to 29 using UV curable ink under the same conditions are also shown for reference.

From the results in Table 12, it can be seen that a lithographic printing plate having a high-definition and high-pressing image portion can be obtained even when a solvent-soluble ink is used. In contrast to Examples 25 to 29, it is understood that when the solvent-soluble ink is used, the printing durability is further improved as compared with the UV curable ink.
Other than the medium wave structure with an average opening diameter of 0.5 to 5 μm and a small wave structure with an average opening diameter of 0.01 to 0.2 μm (surface treatment 10 to 17), one of printing durability and resistance to dirt is practically used. Although it is at a satisfactory level, it can be seen that it is slightly inferior to the optimum one.
Grain shape (surface treatment 1-9) in which a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed. ) Has a good balance between printing durability and resistance to dirt.

  Next, the ink receiving layer described in Table 13 was formed on the surface of the support subjected to the surface treatment 9 and the hydrophilization treatment 5, and the ink 2 was further ejected to produce a lithographic printing plate of Example 105. And evaluated in the same manner. Further, as a control example, the results of Example 14 and Comparative Example 1 which are different only in ink are also shown.

  By using the ink 2 in which F-780 is added to the ink 1, the ink contact angle is changed from 5 ° to 70 °. Therefore, when ink is deposited on the ink receiving layer 24 outside the range of the present invention, the dot formed by the ink 1 is used. The diameter of 130 μm was 30 μm when ink 2 was used. From this, it can be seen that by adding a water-repellent compound to the ink, it is possible to form a high-resolution image without blurring.

[Example 106]
After drawing and exposing the plate described in Example 1 in the same manner as in Example 1, the gum coater G-800H (manufactured by Fuji Photo Film) was charged with a gum solution obtained by diluting GU-7 with water, and the gum was applied. A lithographic printing plate of Example 106 was obtained. Similarly, Example 97 obtained using Ink 3 and Example 102 obtained using Ink 4 were also applied with gum in the same manner as Example 106 to give Examples 107 and 108, respectively. When these were evaluated in the same manner, both the printing durability and the stain resistance were the same as those of Examples 1, 97, and 102, respectively, and it was found that the ink receiving layer in the non-image area was removed by the gum treatment. It was.

It is a side view which shows the concept of the process of the brush lining used for the mechanical roughening process in preparation of the support body for lithographic printing plates of this invention. It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of the support body for lithographic printing plates of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in preparation of the support body for lithographic printing plates of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2, 4 Roller-like brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte path 18 Auxiliary anodes 19a and 19b Thyristor 20 AC power supply 40 Main electrolytic cell 50 Auxiliary anode tank 410 Anodizing apparatus 412 Power supply tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Power supply electrode 422, 428 Roller 424 Nip roller 430 Electrolytic electrode 432 Tank wall 434 DC power supply

Claims (13)

  An ink that contains one or more compounds selected from the group consisting of a hydrophilic layer and a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton on a support, and ejected by an ink jet recording method. A recording medium formed by sequentially laminating ink receiving layers.   The area where ink is not ejected by the ink jet recording method of the ink receiving layer is removed by dampening water during printing performed after the ink ejection and ink curing steps. recoding media.   2. The recording target according to claim 1, wherein a region where ink is not ejected by the ink jet recording method of the ink receiving layer is removed by gum in a gumming step performed after the ink ejection and ink curing steps. Medium.   The said support body has the grain structure of the structure which superimposed the medium wave structure of 0.5-5 micrometers of average aperture diameter, and the small wave structure of average aperture diameter of 0.01-0.2 micrometers. The recording medium according to claim 1.   The support has a grain shape in which a large wave structure having an average wavelength of 5 to 100 μm, a medium wave structure having an average opening diameter of 0.5 to 5 μm, and a small wave structure having an average opening diameter of 0.01 to 0.2 μm are superimposed. The recording medium according to claim 4, wherein the recording medium has a surface.   6. The recording medium according to claim 4, wherein an average of a depth ratio of the support to the opening diameter of the small wave structure is 0.2 or more. The ink receiving layer contains 0.2 to 50.0 mg / m ^{2 of} one or more compounds selected from the group consisting of a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton, and the hydrophilicity the recording medium according to any one of claims 1 to 6, characterized in that the resin contains 1 to 200 mg / ^{m 2.}   An ink that contains one or more compounds selected from the group consisting of a hydrophilic layer and a compound having a fluoroalkyl group and a compound having a dimethylsiloxane skeleton on a support, and ejected by an ink jet recording method. A lithographic printing plate obtained by depositing ink on a surface of a recording medium formed by sequentially laminating ink receiving layers to be received and curing to form an image area.   The contact angle between the ink receiving layer formed on the hydrophilic layer and water is smaller than 10 °, and the contact angle between the ink receiving layer and ink ejected by inkjet is larger than 30 °. The lithographic printing plate according to claim 8.   The lithographic printing plate according to claim 8 or 9, wherein a contact angle between the hydrophilic layer formed on the support and the fountain solution used during printing is smaller than 10 °.   The ink receiving layer surface of the recording medium according to any one of claims 1 to 7 is ejected with ink by an ink jet recording method and cured, and then the region other than the region where the ink is ejected. A method for preparing a lithographic printing plate, wherein the ink receiving layer is removed.   12. The method for preparing a lithographic printing plate according to claim 11, wherein the removal of the ink receiving layer is performed with dampening water during printing.   12. The method for preparing a lithographic printing plate according to claim 11, wherein the ink receiving layer is removed by gum in the gum treatment step.

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