JPH11208138A - Manufacture of support for lithographic printing plate, support for lithographic printing plate, and photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a support for a lithographic printing plate by which it is possible to obtain a photosensitive lithographic printing plate capable of stably manufacturing high-quality print, a support for a lithographic printing plate, and a photosensitive lithographic printing plate. SOLUTION: This method for manufacturing a support for lithographic printing performs the electrolytic surface roughing treatment of an Al-size plate a few times in an acidic electrolyte with at least, two electrolytic cells using an alternating current waveform 1 whose polarity changes alternately. Further, the shape of an alternating current waveform to be used for at least, one electrolytic cell is made different from the shape of an alternating current waveform to be used for the other electrolytic cell. The method for manufacturing the support for lithographic printing is such that, after forming pits, each of which has an opening dia. of 2-30 μm, the edge part of each of the pits may be selectively removed. In addition, the support for lithographic printing is of such a construction that the pits with an opening dia. of 0.2-0.8 μm are overlapped among the pits having an opening dia. of 2-30 μm and the edge parts of the pits with an opening dia. of 2-30 μm are smooth. The photosensitive lithographic printing plate is formed by coating a photosensitive resin on the support for lithographic printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for preparing a lithographic printing plate support, a lithographic printing plate support, and a photosensitive lithographic printing plate.

[0002]

2. Description of the Related Art Conventionally, a photosensitive lithographic printing plate (hereinafter sometimes referred to as a PS plate) has been formed by forming a photosensitive layer such as a photosensitive resin layer or the like on an appropriate support. Have been done. The support for forming the PS plate is usually subjected to surface treatment to roughen the surface.

Heretofore, as one method of roughening the surface of a PS plate support, a roughening method by electrolytic treatment has been used. In this case, as a technique for easily controlling the shape, there is a prior art using various AC waveforms. For example, JP-B-55-19191 and JP-B-56-19.
No. 280, a method using an AC waveform in which the voltage at the anode is larger than the voltage at the cathode;
-22036, a method using a waveform obtained by controlling the phase of a sine wave with a thyristor, a method using a three-phase alternating current described in Japanese Patent Publication No. 58-157997, and a method using a three-phase alternating current method. A method using an alternating current obtained by superposing alternating currents having different frequencies described in Japanese Patent Application Laid-Open No. 207374 is known.

However, in such electrolytic surface roughening using a single alternating current waveform, it is insufficient to control the shape distribution of the pits. The photosensitive lithographic printing plate formed by applying the composition tends to have a variation in performance depending on the plate position, and thus it is difficult to control the printing plate.

Further, in the conventional surface roughening method by electrolytic treatment, the upper edge (edge) of the formed pit remains unavoidably. A photosensitive lithographic printing plate using a support having this edge portion is liable to stain during development and printing,
For example, a background stain, a non-image area stain, a stop stain, a blanket stain, and the like are caused by under development.

Further, there is a problem in that the ball-point pen ink drawn on the non-image portion remains without being removed even after development and adheres to the plate surface, causing a problem that the portion is stained during printing (ball-point pen remaining).

In order to solve these problems, a method (desmutting) of removing an edge portion by immersing in an aqueous alkali solution such as sodium hydroxide after electrolytic treatment is generally adopted. It is difficult to selectively remove only the edges of the pits, and the formed pits themselves dissolve. For this reason, the above-mentioned problems have not been sufficiently solved.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to produce a lithographic printing plate support capable of obtaining a photosensitive lithographic printing plate capable of stably producing high-quality printed matter. It is an object of the present invention to provide a method, to provide a support for such a lithographic printing plate, and to provide such a photosensitive lithographic printing plate.

[0009]

In order to solve the above-mentioned problems, a method for producing a lithographic printing plate support according to the present invention comprises:
In a method for producing a lithographic printing plate support, an aluminum plate is subjected to electrolytic surface roughening treatment a plurality of times in an acidic electrolytic solution having at least two electrolytic baths by using an alternating current waveform in which polarity is changed alternately. The configuration is such that the shape of the alternating current waveform used for the electrolytic cell is different from the shape of the alternating current waveform used for the other electrolytic cells.

[0010] In another method for producing a lithographic printing plate support according to the present invention, an aluminum plate is formed in an acidic electrolytic solution having at least two electrolytic cells by using an alternating current waveform whose polarity changes alternately. In a method for producing a lithographic printing plate support which is subjected to electrolytic surface roughening treatment a plurality of times, after forming a pit having an opening diameter of 2 to 30 μ, an edge portion of the pit is selectively removed. To

[0011] In order to solve the above-mentioned problems, a lithographic printing plate support according to the present invention uses an aluminum plate in an acidic electrolytic solution having at least two electrolytic cells by using an alternating current waveform whose polarity changes alternately. And the alternating current waveform used for at least one electrolytic cell is different from the shape of the alternating current waveform used for other electrolytic cells. The configuration is characterized by the following.

Another lithographic printing plate support according to the present invention is a method for electroplating an aluminum plate a plurality of times in an acidic electrolytic solution having at least two electrolytic cells by using an alternating current waveform having alternating polarities. After roughening, 2-30
After a pit having an opening diameter of μ is formed, an edge portion of the pit is selectively removed to form the pit.

Further, still another lithographic printing plate support according to the present invention is a lithographic printing plate support comprising 2 to 30 μm.
Having a structure in which pits having an opening diameter of 0.2 to 0.8 μ are superimposed on pits having an opening diameter of
The pit having an opening diameter of 0μ has a smooth edge portion.

In order to solve the above-mentioned problems, a support for a photosensitive lithographic printing plate according to the present invention comprises a lithographic printing plate support obtained by anodizing each of the lithographic printing plate supports according to the present invention. The photosensitive resin layer is formed on the body by coating.

According to the present invention, the following (1) to (1) are listed.
The effect of (4) was obtained, so that the problems of the prior art could be solved, and surprisingly, the following effect of (5) was also obtained.

(1) Uniform and dense pits were formed on the support. As a result, the performance variation of the photosensitive lithographic printing plate using this support was reduced. (2) It is difficult to stain during printing. For this reason, the supply amount of dampening water can be reduced, and the water can be squeezed. Thereby, the ink density in the image area is increased, and a high-quality printed matter is obtained. In addition, stop dirt and blanket dirt are reduced. (3) Dirt due to the under phenomenon is reduced. For this reason,
The development latitude is also widened. (4) The problem of remaining ballpoint pens is eliminated. Therefore, the adhesion of stains to printed matter is eliminated. (5) The fountain solution resistance (H solution resistance) of the printing plate image portion during printing is improved.

Hereinafter, the present invention will be further described. In the method for producing a lithographic printing plate support according to the present invention, the shape of the alternating current waveform used for at least one electrolytic cell is different from the shape of the alternating current waveform used for the other electrolytic cells. To In this case, the current density, the phase (excluding the sine wave), and the frequency in the alternating current waveforms may be arbitrarily changed. Preferred current densities will be described later in the description relating to surface roughening.

If the different alternating current waveform shapes are accompanied by a phase shift, the preferred phase shift is 5 to 175 degrees. More preferably, it is 20 to 150 degrees.

The preferred frequency of the alternating current waveform used is
It is 5-250 Hz. More preferably, 10 to 10
0 Hz.

The alternating current used may have any waveform. Preferably, it is a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave, or a sawtooth wave. Preferred sawtooth waveforms are, for example, waveforms (32) to (41) shown in FIGS. In the figure, S is the time from the start point of one cycle of the waveform, and in the waveforms (32) to (36), (40), and (41), S =
1.5 msec is preferred. E is the time from the end point of one cycle of the waveform, and in the waveforms (33), (39), and (41), E is preferably 1.0 msec. In addition, a combination of the above waveforms at the time of the anode and the time of the cathode can also be used. Preferable combinations of such waveforms are, for example, waveforms (7) to (31) shown in FIGS.

The anode time / cathode time of the waveform to be used is 0.
It is preferably from 2 to 2.0. More preferably,
0.5 to 1.5.

The amount of anode electricity / cathode electricity of the waveform used is:
It is preferably from 0.5 to 2.0. More preferably, it is 0.7 to 1.5.

As the electrolytic solution, various ones can be used as described in the explanation of surface roughening described later, but hydrochloric acid or a mixed system of hydrochloric acid / acetic acid is preferable.

By forming a photosensitive layer on a support,
A photosensitive lithographic printing plate can be obtained. As the photosensitive composition for forming a photosensitive layer, when the support according to the present invention is used as a lithographic printing plate, generally, after the post-treatment, a positive-type or negative-type photosensitive layer is applied to obtain a photosensitive composition. A lithographic printing plate is obtained.

Specifically, the positive photosensitive layer is disclosed in Japanese Patent Application Nos. 5-15499, 6-190163 and 6-3.
No. 33805, No. 7-2218986, No. 7-337
No. 687, and JP-A Nos. 2-219060 and 2-219060.
JP-A-2-217759, JP-A-2-189544, JP-A-64-56442, JP-A-62-78544, JP-B-3-56622, JP-A-4-176228, and JP-A-6-178228.
Nos. 3,313,805 and 7,22,1986, and the photosensitive layer for CTP are described in Japanese Patent Application No. 7-231.
444 and JP-A-3-87833 can be used.

The coating amount of the photosensitive layer is 0.8 to 2.
It is preferably 5 g / m ² , more preferably
1.2 to 1.8 g / m ² . A matting agent can be applied to the photosensitive layer as needed. Furthermore, in order to prevent scratches on the photosensitive layer when the photosensitive lithographic printing plates are stacked,
Further, in order to prevent the elution of the aluminum component into the developer during development, JP-A-50-151136, JP-A-57-63293, JP-A-60-73538, and JP-A-61-67863. JP, JP-A-6-351
A process of providing a protective layer on the back surface of the support as described in JP-A-74-174 can be performed.

[0027] Aluminum supports that can be used in the practice of the support according to the present invention include supports made of pure aluminum and aluminum alloys. Various aluminum alloys can be used, for example, silicon, copper, manganese, magnesium, chromium, zinc, lead,
An alloy of aluminum with a metal such as bismuth, nickel, titanium, sodium, or iron can be used.

Prior to roughening, the aluminum support is preferably subjected to a degreasing treatment mainly for removing rolling oil on the aluminum surface. As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion of kerosene, triethanol or the like can be used. In the degreasing treatment, an aqueous solution of an alkali such as caustic soda can be used. When an aqueous solution of an alkali such as caustic soda is used for the degreasing treatment, dirt and oxide films that cannot be removed only by the above degreasing treatment can be removed. When an aqueous solution of an alkali such as caustic soda is used for the degreasing treatment, it is preferable to immerse in an acid such as phosphoric acid, nitric acid, hydrochloric acid, sulfuric acid, chromic acid, or a mixed acid thereof to perform a neutralization treatment. When electrochemical surface roughening is performed after the neutralization treatment, it is particularly preferable to match the acid used for neutralization with the acid used for electrochemical surface roughening.

In the present invention, the surface is roughened by using an alternating current in an acidic electrolytic solution. As the acidic electrolyte, various ones used in a usual electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolyte is preferably used.

In the surface roughening treatment, the entire amount of electricity required for the treatment may be continuously applied in one step to carry out the treatment, or the electrolysis treatment may be carried out with a suitable pause time or with a reduced current density. It is also possible to divide the time into several times by arranging time. In the case where the surface is divided and roughened, the amount of positive electricity in one division step is set to 100 C / dm ² or less, and the pause time or the time during which the electrolytic treatment is slow is set to 0.6 to 5 seconds. preferable. In the case where the surface is divided and roughened, it is preferable to use a hydrochloric acid-based electrolytic solution, whereby a uniform grain can be formed.

When the surface is roughened using a nitric acid-based electrolyte, the applied voltage is preferably 1 to 50 V,
5-30V is more preferable. The current density (peak value) is preferably 10 to 200 A / dm ² , and 20 to 150 A / dm ²
dm ² is more preferred. Quantity of electricity by summing all the process steps, preferably 100~2000C / dm ^2, more preferably 200~1500C / dm ^2, more preferably from 200~1000C / dm ^2. Temperature is 10-5
0 ° C is preferable, and 15 to 45 ° C is more preferable. The nitric acid concentration is preferably from 0.1 to 5% by weight, particularly preferably from 0.5 to 2.0% by weight. If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

When the surface is roughened using a hydrochloric acid-based electrolyte, the applied voltage is preferably 1 to 50 V,
5-30V is more preferable. The current density (peak value) is preferably 10 to 200 A / dm ² , and 20 to 150 A / dm ²
dm ² is more preferred. Quantity of electricity by summing all the process steps, preferably 100~2000C / dm ^2, more preferably 200~1500C / dm ^2, more preferably from 200~1000C / dm ^2. Temperature is 10-5
0 ° C is preferable, and 15 to 45 ° C is more preferable. The hydrochloric acid concentration is preferably from 0.1 to 5% by weight, particularly preferably from 0.5 to 2.0% by weight. If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, etc. can be added to the electrolytic solution. % Is preferably added.

The support roughened by the method of the present invention is preferably immersed in an aqueous solution of an acid or alkali to etch the surface in order to remove the surface smut and the like and control the pit shape. . This is a so-called desmutting process. Acids that can be used include, for example, sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like, and bases that can be used include, for example, sodium hydroxide, potassium hydroxide, and the like. Among these, it is preferable to use an aqueous solution of an alkali. The etching amount is particularly preferably 1.0 to 3.0 g / m ² as a weight reduction amount including smut. When the above treatment is performed by immersion treatment in an aqueous alkali solution, phosphoric acid, nitric acid, sulfuric acid, acids such as chromic acid,
Alternatively, it is preferable to perform a neutralization treatment by dipping in a mixed acid thereof. When performing anodizing treatment after neutralization treatment, it is particularly preferable to match the acid used for neutralization with the acid used for anodizing treatment.

It is a preferable embodiment to perform anodizing treatment after the surface roughening treatment. Anodizing is generally performed by
DC electrolysis is performed using sulfuric acid or phosphoric acid or a mixed aqueous solution of both. A method of electrolyzing at a current density of 1 to 10 A / dm ² is preferably used. Other examples include a method of electrolyzing at a high current density in sulfuric acid described in US Pat. No. 1,412,768, and US Pat. Patent No. 3,51
No. 1,661, there is a method of electrolysis using phosphoric acid. The thickness of the anodic oxide film is 0.5
To 5.0 g / m ² , preferably 1.5 to 3.5 g / m ²
Is more preferred. The density of the generated micropores is preferably 400 to 700 / m ² , and
0 / m ² is more preferable.

If necessary, post-processing can be performed as appropriate. For example, the anodized aluminum plate may be subjected to a sealing treatment as needed. Examples of the sealing treatment include a boiling treatment, a steam treatment, a sodium silicate treatment, a dichromate aqueous solution treatment, a nitrite treatment, and an ammonium acetate treatment. Further, after the sealing treatment, a hydrophilic undercoat layer may be provided. As the hydrophilic undercoat layer, U.S. Pat.
No. 461, the hydrophilic metal cellulose described in U.S. Pat. No. 1,860,426, JP-A-60-149949 and JP-A-63-165183. Described amino acids and salts thereof, hydroxyl-containing amines and salts thereof described in JP-A-60-232998, phosphates described in JP-A-62-19494, and JP-A-59-101651. Polymer compounds containing the above-mentioned monomer unit having a sulfo group can be exemplified.

[0036]

Embodiments of the present invention will be described below. As a matter of course, the present invention is not limited by the following embodiments. A comparative example will be described together with an example.

An aluminum plate having a thickness of 0.24 mm (material: 1050, tempered H16) was immersed in a 1% aqueous solution of sodium hydroxide kept at 50 ° C. to dissolve 2.0 g / m 2.
After washing with water performed dissolution treatment at ^2, an aqueous solution of electrolytic treatment in the same composition was immersed for 10 seconds to perform the next maintained at 25 ° C., subjected to neutralization treatment, and then washed with water.

Next, this aluminum plate was subjected to the conditions shown in Table 1 and the waveforms shown in FIGS.
Electrolytic surface roughening treatment was performed. At this time, the temperature of the electrolytic solution was 25.
° C, and the distance between the electrode and the web surface was 10 mm.
After the electrolytic surface roughening, it was immersed in a 1% aqueous sodium hydroxide solution kept at 50 ° C., and etched so that the dissolved amount including the smut of the roughened surface became 2.0 g / m ^2. ,
Next, it was immersed in a 10% aqueous sulfuric acid solution maintained at 25 ° C. for 10 seconds, neutralized, and then washed with water. Next, in a 20% sulfuric acid aqueous solution, the amount of electricity is 15 under a constant voltage condition of DC 20V.
Anodizing treatment was performed so as to be 0 C / dm ² to obtain a support.

Next, a photosensitive composition coating solution 1 to 4 having the following composition shown in Table 2 was applied to each support using a wire bar, dried at 80 ° C., and dried. I got At this time, the application amount of the photosensitive composition was 1.6.
g / m ² .

(Photosensitive Composition 1) Polymer Compound 1 0.20 g Hydroxypropyl-β-cyclodextrin 0.20 g Novolak resin 3.70 g (Mole ratio of phenol / m-cresol / p-cresol is 10/54/36. Novolak resin 3.30 g (Mole ratio of phenol / m-cresol / p-cresol is 20/50/30 and Mw is 8000) Pyrogallol acetone resin (Mw: 3000) and O-naphthoquinonediazide-5-sulfonyl chloride Condensate (esterification ratio 30%) 1.50 g Polyethylene glycol # 2000 0.20 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.09 g 2,4-bis (trichloromethyl) -6- (P-methoxystyryl) ) -S-Triazine 0.15 g Fluorine type surfactant FC-430 (manufactured by Sumitomo 3M Co., Ltd.) 0.05 g cis-1,2-cyclohexanedicarboxylic acid 0.20 g methyl ethyl ketone / propylene glycol monomethyl ether = 3/7 (wt%) 90.0 g

[0041]

Embedded image

(Photosensitive Composition 2) Polymer Compound 2 0.50 g Novolak resin 6.50 g (Mole ratio of phenol / m-cresol / p-cresol is 10/54/36 and Mw is 3500) Pyrogallol acetone resin (Mw: 2000) and O-naphthoquinonediazide-5-sulfonyl chloride condensate (esterification ratio 30%) 1.70 g polyethylene glycol # 2000 0.20 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 g 2,4 -Bis (trichloromethyl) -6- (P-methoxystyryl) -S-triazine 0.15 g Fluorinated surfactant FC-430 (manufactured by Sumitomo 3M) 0.03 g cis-1,2, cyclohexanedicarboxylic acid 0 .15 g methyl cellosolve / ethyl cellosolve = 3/7 (wt%) 80.0g

[0043]

Embedded image

(Photosensitive composition 3) Polymer compound 3 1.20 g Novolak resin 6.50 g (Mole ratio of phenol / m-cresol / p-cresol is 10/54/36 and Mw is 4000) Pyrogallol acetone resin (Mw: 2000) and condensate of O-naphthoquinonediazide-5-sulfonyl chloride (esterification rate 30%) 1.40 g Condensate of condensed resin of p-cresol with formaldehyde (Mw: 1500) and O-naphthoquinonediazido-4-sulfonyl chloride (Esterification ratio 40%) 0.30 g Polyethylene glycol # 2000 0.20 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.06 g Ethyl violet 0.02 g 2,4-bis (trichloromethyl) -6- (P -Methoxystyryl) -S-tri Jin 0.15g Fluorine type surfactant FC over 430 (Sumitomo 3M Ltd. (Ltd.)) 0.03 g cis over 1,2-cyclohexanedicarboxylic acid 0.20g of methyl cellosolve / ethyl cellosolve = 3/7 (wt%) 77.0g

[0045]

Embedded image

(Photosensitive composition 4) m-cresol-formaldehyde novolak resin (Mw: 1700) 0.30 g cresol-formaldehyde novolak resin (m-cresol / p-cresol molar ratio is 80/20 and Mw: 3000) 1.10 g Condensate of pyrogallol acetone resin with O-naphthoquinonediazide-5-sulfonyl chloride 0.45 g (as described in examples of U.S. Pat. No. 3,635,709) Tetrahydrophthalic anhydride 0 .10 g benzoic acid 0.02 g t-butylphenol resin (described in the examples of US Pat. No. 4,123,279) 0.01 oil blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.) 0.044 -[P-N- (p-hydroxybenzoyl) aminophenyl] -2,6 Bi scan (trichloromethyl) -S- Torijian 0.02 g (manufactured by Dainippon Ink &) Megafac F177 0.02 g Methyl ethyl ketone 15.0g methyl isobutyl ketone 5.0g Propylene glycol monomethyl ether 10.0g

(Pit uniformity) The pit uniformity is as follows.
It means having a structure in which small pits are superimposed on the following large pits. As an evaluation method, a photograph was taken of the surface of the produced support using a SEM with a magnification of 500, and good / bad judgment was visually performed. Here, a large pit refers to one having an opening diameter of 2 to 30 μm in all pits, and a small pit refers to one having an opening diameter of 0.1 to 2 μm in all pits. Pits smaller than 0.1 μm were ignored.

(Smoothness of Pit Edge) SEM observation was performed in the same manner as in the uniformity of pits, and whether the edge was smooth or not was evaluated by visual inspection.

(Evaluation of Stain Resistance When Squeezing Water) As shown in Table 1, a printing plate obtained by coating the photosensitive composition was prepared as follows.
A halftone dot film of a positive image is superimposed, exposed using a 4 kW metal halide lamp, and developed with a developer obtained by diluting SDR-1 (manufactured by Konica Corporation) 6 times with water at 27 ° C. for 20 seconds.
Guming is performed by SGW-3 (manufactured by Konica Corporation), applied to a printing machine (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), coated paper, dampening solution (etching solution SG-51 manufactured by Tokyo Ink Co., Ltd.). , Density 1.5%) and ink (Hi-Echo M black manufactured by Toyo Ink Mfg. Co., Ltd.), and printing was performed with the density of the image portion being 1.8. Here, the degree of soiling when the dampening water distribution was suppressed was compared, and evaluation of good / bad was made.

The evaluation criteria are as follows. ○ Dirt did not occur △ Slightly dirty × Partial to overall

(Stop smearing property)
Except that the dampening water distribution is not suppressed, printing is performed under the same conditions as in the above "Evaluation of the difficulty of contamination when water is squeezed out". When the 5000 sheets have been printed, the printing press is stopped once and left for one hour. After the printing, the printing is resumed,
^It was evaluated by the number in ² .

(Blanket dirt) The obtained lithographic printing was printed under the same conditions as in the above "Evaluation of dirt difficulty when squeezing out water" except that the amount of dampening water supplied was not suppressed.
At the time of printing 00 sheets, the printing press was once stopped, and the degree of stain of the non-image area on the blanket with the ink was visually evaluated.

The evaluation criteria are as follows. ○ Almost dirty △ Somewhat dirty × Extremely dirty

(Under developability) The obtained lithographic printing was subjected to a full-surface exposure for 60 seconds from a distance of 90 cm with a 4 kW metal halide lamp to obtain SDR-1 (Konica Corporation).
Was developed at 27 ° C. for 20 seconds with a developer diluted 9-fold with water. The developed ink PI-2 (manufactured by Fuji Photo Film Co., Ltd.) was applied on the plate surface after development, and the adhesion of the ink was visually evaluated.

The evaluation criteria are as follows. ○ Not adhered △ Slightly adhered × Extremely adhered

(Remaining Ballpoint Pen) After drawing a ballpoint pen (blue ink) on the printing plates of Examples and Comparative Examples with a load of 75 g, the entire surface was exposed for 60 seconds from a distance of 90 cm with a 4 kW metal halide lamp, and SDR-1 (Konica (Manufactured by Co., Ltd.) diluted 6 times with water at 27.degree.
Developed for seconds. After the development, the grain was judged to be a perfect score of 5 points, and 0 points when the ink was not completely removed.

(H solution resistance) 100% halftone dots (solid), 50% halftone dots, and 0.5%
A film manuscript with small dots up to 5%
Exposure was performed for 60 seconds from a distance of 90 cm using a W metal halide lamp, and development was carried out at 27 ° C. for 20 seconds with a developer obtained by diluting SDR-1 (manufactured by Konica Corporation) 6 times with water. Further, this sample was exposed under the same conditions as described above except that a film original was not used, and H-solution SG-5 manufactured by Tokyo Ink Co., Ltd. was used.
1 was immersed in a 10% aqueous solution at room temperature for 1 hour, washed with water and dried. Then, the shape change of solid and 50% halftone dots and small dot reproducibility were visually evaluated.

The evaluation criteria are as follows. Solid change 50% change in halftone dot shape ○ No change in shape ○ No change in shape △ Slight defect is observed △ Slightly distorted point shape × Obvious defect is observed × Clearly distorted point shape Out

Small dot reproducibility 0.5% to 5%, the smallest halftone dot percentage at which points are maintained without defects.

As can be understood from Table 2, the samples of the examples of the present invention were evaluated for uniformity of pits, smoothness of pit edges, difficulty in staining when water was squeezed, stop stainability,
Blanket dirt, under developability, ballpoint pen residue,
All of the H liquid resistances were good. On the other hand, in the comparative example, good results were not obtained.
In addition, although the case where the waveforms 36 to 41 shown in FIGS. 36 to 41 were appropriately combined and used was separately performed, according to the method of the present invention, similarly good results were obtained.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

As described above, according to the present invention, there is provided a method for producing a lithographic printing plate support capable of obtaining a photosensitive lithographic printing plate capable of stably producing a high quality printed matter.
Such a lithographic printing plate support was provided, and such a photosensitive lithographic printing plate was able to be provided.

[Brief description of the drawings]

FIG. 1 shows an alternating current waveform used (1).

FIG. 2 shows an alternating current waveform used (2).

FIG. 3 shows an alternating current waveform used (3).

FIG. 4 shows an alternating current waveform used (4).

FIG. 5 shows the alternating current waveform used (5).

FIG. 6 shows an alternating current waveform used (6).

FIG. 7 shows an alternating current waveform used (7).

FIG. 8 shows an alternating current waveform used (8).

FIG. 9 shows an alternating current waveform used (9).

FIG. 10 shows an alternating current waveform used (10).

FIG. 11 shows an alternating current waveform used (11).

FIG. 12 shows an alternating current waveform used (12).

FIG. 13 shows an alternating current waveform used (13).

FIG. 14 shows an alternating current waveform used (14).

FIG. 15 shows an alternating current waveform used (15).

FIG. 16 shows an alternating current waveform used (16).

FIG. 17 shows an alternating current waveform used (17).

FIG. 18 shows a used alternating current waveform (18).

FIG. 19 shows an alternating current waveform used (19).

FIG. 20 shows an alternating current waveform used (20).

FIG. 21 shows an alternating current waveform used (21).

FIG. 22 shows an alternating current waveform used (22).

FIG. 23 shows a used alternating current waveform (23).

FIG. 24 shows an alternating current waveform used (24).

FIG. 25 shows the alternating current waveform used (25).

FIG. 26 shows a used alternating current waveform (26).

FIG. 27 shows a used alternating current waveform (27).

FIG. 28 shows a used alternating current waveform (28).

FIG. 29 shows a used alternating current waveform (29).

FIG. 30 shows a used alternating current waveform (30).

FIG. 31 shows an alternating current waveform used (31).

FIG. 32 shows the alternating current waveform used (32).

FIG. 33 shows the alternating current waveform used (33).

FIG. 34 shows the alternating current waveform used (34).

FIG. 35 shows a used alternating current waveform (35).

FIG. 36 shows a used alternating current waveform (36).

FIG. 37 shows the alternating current waveform used (37).

FIG. 38 shows the alternating current waveform used (38).

FIG. 39 shows the alternating current waveform used (39).

FIG. 40 shows the alternating current waveform used (40).

FIG. 41 shows a used alternating current waveform (41).

[Explanation of symbols]

 1 to 41 (alternating current) waveforms.

Claims (10)

[Claims] 1. A method for preparing a lithographic printing plate support, comprising subjecting an aluminum plate to electrolytic surface roughening a plurality of times in an acidic electrolytic solution having at least two electrolytic baths, using an alternating current waveform of alternating polarity. 3. The method for producing a lithographic printing plate support according to claim 1, wherein the shape of the alternating current waveform used for at least one electrolytic cell is different from the shape of the alternating current waveform used for another electrolytic cell. 2. The method for producing a lithographic printing plate support according to claim 1, wherein the current density of one electrolytic cell is higher than the current density of another electrolytic cell. 3. A method for producing a lithographic printing plate support, wherein an aluminum plate is subjected to electrolytic surface roughening treatment a plurality of times in an acidic electrolytic solution having at least two electrolytic baths by using an alternating current waveform of alternating polarity. 3. A method for producing a lithographic printing plate support, comprising: forming a pit having an opening diameter of 2 to 30 μm; and selectively removing an edge of the pit. 4. The method according to claim 3, wherein the current density of one electrolytic cell is higher than the current density of another electrolytic cell. 5. An aluminum plate is subjected to electrolytic surface roughening treatment a plurality of times in an acidic electrolytic solution having at least two electrolytic cells by using an alternating current waveform of alternating polarity, and at least one electrolytic cell is treated. A lithographic printing plate support characterized in that the shape of the alternating current waveform used in the step is different from the shape of the alternating current waveform used in another electrolytic cell. 6. An aluminum plate is subjected to electrolytic surface roughening treatment in an acidic electrolytic solution having at least two electrolytic cells a plurality of times using an alternating current waveform of alternating polarity, and an opening diameter of 2 to 30 μm is formed. A lithographic printing plate support, comprising: forming a pit having the pit; and selectively removing an edge of the pit. 7. A lithographic printing plate support comprising 0.2 to 0.8 μm in a pit having an opening diameter of 2 to 30 μm.
A lithographic printing plate support having a structure in which pits having an opening diameter of μ are superimposed, and the edges of the pits having an opening diameter of 2 to 30 μ are smooth. 8. A lithographic printing plate support according to claim 5, which is formed by applying a photosensitive resin layer on a lithographic printing plate support obtained by anodizing the support. Photosensitive lithographic printing plate. 9. A lithographic printing plate support according to claim 6, which is formed by applying a photosensitive resin layer onto a lithographic printing plate support obtained by anodizing the support. Photosensitive lithographic printing plate. 10. A lithographic printing plate support according to claim 7, which is formed by applying a photosensitive resin layer on a lithographic printing plate support obtained by anodizing. Photosensitive lithographic printing plate.