JP4648057B2 - Method for producing support for lithographic printing plate - Google Patents

Description

  The present invention relates to a method for producing a lithographic printing plate support.

  An aluminum support for a lithographic printing plate (hereinafter simply referred to as “support for a lithographic printing plate”) used in a lithographic printing plate is produced by subjecting an aluminum plate to a surface roughening treatment or other surface treatment. Examples of the roughening treatment include mechanical roughening, electrochemical roughening (electrolytic roughening), chemical roughening (chemical etching), and a combination of these. The method is known.

Among these, the mechanical surface roughening treatment is effective for improving the printing durability of the lithographic printing plate. As a mechanical surface roughening treatment, a method of spraying an abrasive slurry between a rotating nylon brush and an aluminum plate is generally known.
However, this method using a nylon brush and an abrasive has the advantage that it can be carried out at a high speed and at a low cost. On the other hand, it is difficult to control the particle size of the abrasive. Deep recesses are easily generated. As a result, when there is a locally deep recess on the surface of the lithographic printing plate support, in the lithographic printing plate provided with a positive image recording layer, the locally deep portion of the non-image part is difficult to be developed, In a lithographic printing plate provided with a negative type image recording layer, there arises a problem of poor sensitivity that a locally deep portion of an image portion is difficult to form as an image.
In addition, since the method using a nylon brush and an abrasive physically roughens, a sharpened portion is generated. Therefore, in order to smooth the portion, a large amount of aluminum is added by an alkali etching treatment in a later step. Must be dissolved. Therefore, there is a problem that the cost is high and the load on the environment is large.

In order to solve these problems, Patent Document 1 proposes a method of manufacturing a lithographic printing plate support in which an aluminum plate surface is roughened by transfer and then the surface of the aluminum plate is roughened with a brush.
Further, in Patent Document 2, an oval press recess is formed on an aluminum plate at a density of 200 pieces / mm ² or more and a part of the press recess overlaps to form a wavy pattern. Methods have been proposed for performing electrolytic surface roughening of hydrochloric acid.
Further, in Patent Document 3, “a radiation-sensitive recording layer is provided on a roll-treated and embossed aluminum support, and the aluminum support has pits having an average diameter of 10 to 60 μm, preferably 20 to 24 μm. A printing plate having a surface structure having an indentation microstructure having an indentation diameter in the range of 0.1 to 6 μm, which is made by electrochemical roughening, is superimposed on the surface structure. "Printed version" has been proposed.

  Further, for the various problems described above, the applicant of the present patent application stated that “(1) using an aluminum plate with irregularities formed on the surface by transferring an irregular pattern, (1) electrochemically roughening in an aqueous nitric acid solution. Surface treatment, (2) electrochemical surface roughening treatment in aqueous hydrochloric acid, and (3) anodizing, ”a method for producing a lithographic printing plate support, Aluminum plate with concavo-convex pattern, at least mechanical roughening treatment using rotating brush and abrasive, electrochemical roughening treatment using alternating current in aqueous solution containing nitric acid, containing hydrochloric acid Proposed a method for producing a support for a lithographic printing plate in which an electrochemical surface roughening treatment and an anodizing treatment using alternating current in an aqueous solution are performed in this order (see Patent Documents 4 and 5).

JP-A-6-183168 JP 60-36195 A JP 2002-240448 A JP 2005-7857 A Japanese Patent Laid-Open No. 2005-7751

However, even when the methods described in Patent Documents 1 to 4 are used, the unevenness formed on the surface of the aluminum plate may be accompanied by plastic deformation, and the surface of the aluminum plate is rolled with a pass roll or the like. It was found that a small piece of aluminum (hereinafter also referred to as “AL small piece”) is easily peeled off and separated from a part of the plastic deformation portion of the unevenness (hereinafter also referred to as “flap”). . Specifically, when the surface of the aluminum plate is observed from directly above with an electron microscope at a magnification of 500 to 1000 times, preferably 700 to 800 times, a surface having an oval concave portion and a raised portion (the above flap) is obtained. Observed (see FIG. 1).
In addition, when the AL piece is attached to the pass roll or the pass roll is made of rubber in the manufacturing process of the support for the planographic printing plate conveyed through a plurality of pass rolls (for example, during the long production of the support for the planographic printing plate) It has been found that the surface of the aluminum plate may be sunk into the surface and fixed on the roll surface, and the subsequent aluminum plate surface may be scratched with periodicity according to the pass roll diameter.

  On the other hand, the method described in Patent Document 5 eliminates the AL small piece by performing a mechanical surface roughening process using a rotating brush and an abrasive on an aluminum plate having a concavo-convex pattern on the surface. Although it is considered effective, it has been found that the uniform uneven shape transferred to the surface of the aluminum plate by the roll may be greatly deformed.

  Therefore, the present invention provides a support for a lithographic printing plate that can prevent the generation of scratches originating from the AL pieces without breaking the uniform unevenness transferred to the aluminum plate surface by the roughened roll. It aims to provide a method.

  As a result of diligent research to achieve the above object, the present inventor is a method for producing a support for a lithographic printing plate that transfers a concavo-convex shape onto the surface of an aluminum plate using a roughened roll (having a concavoconvex surface). When the surface of the aluminum plate is removed from the micro ridges such as the above-mentioned flaps and AL pieces and subjected to the electrolytic surface-roughening treatment, it is derived from the AL pieces without breaking the uniform uneven shape formed by the transfer. The present inventors have found that scratches can be prevented and completed the present invention.

That is, the present invention provides the following (1 ) .
(1) An aluminum plate having a surface having an arithmetic average roughness _Ra of 0.5 to 1.0 μm having a micro-bulge and an uneven shape transferred using a roughened roll, at least the micro-bulge some or all removed parts, pretreatment to reduce the arithmetical mean roughness R _a, and subjected to electrochemical graining treatment in this order to prepare a lithographic printing plate support, a lithographic printing plate A method of manufacturing a support,
The arithmetic mean roughness R _a after applying the pre-treatment is 0.3～0.9Myuemu,
A method for producing a support for a lithographic printing plate, wherein the pretreatment comprises a repeated bending treatment for the aluminum plate 5 times or more and a subsequent chemical etching treatment using an alkaline solution.

  According to the present invention, in the production of a lithographic printing plate support, it is possible to prevent the occurrence of scratches derived from the AL pieces without breaking the uniform uneven shape transferred to the aluminum plate surface by the roughened roll. it can.

Hereinafter, the present invention will be described in detail.
[Method for producing support for lithographic printing plate]
<Aluminum plate (rolled aluminum)>

  A known aluminum plate can be used in the method for producing a lithographic printing plate support of the present invention. The aluminum plate used in the present invention is a metal whose main component is dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements can also be used.

  In the present specification, various substrates made of the above-described aluminum or aluminum alloy are generically used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, copper, manganese, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the content of the foreign elements in the alloy is 10% by mass or less. It is.

  Moreover, as an unavoidable impurity, the remainder of an aluminum plate consists of Al and an unavoidable impurity, for example. Most of the inevitable impurities are contained in the Al ingot. If the inevitable impurities are contained in, for example, a metal having an Al purity of 99.7%, the effects of the present invention are not impaired. For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.

  Thus, the composition of the aluminum plate used in the present invention is not specified. For example, a conventionally known material described in the fourth edition of the Aluminum Handbook (1990, published by the Light Metal Association), for example, JIS Al-Mn based aluminum plates such as A1050, JIS A1052, JIS A1100, JIS A1070, JIS A3004 containing Mn, and internationally registered alloy 3103A can be used as appropriate. For the purpose of increasing the tensile strength, an Al—Mg alloy or an Al—Mn—Mg alloy (JIS A3005) in which 0.1% by mass or more of magnesium is added to these aluminum alloys can also be used. Furthermore, an Al—Zr alloy or an Al—Si alloy containing Zr or Si can also be used. Furthermore, an Al—Mg—Si based alloy can also be used.

Moreover, the aluminum plate obtained by rolling the UBC (Used Beverage Can) ingot which melt | dissolved the used aluminum beverage can can also be used.
In the present invention, Si: 0.07 to 0.09 mass%, Fe: 0.20 to 0.5 mass%, Cu: 0 to 0.3 mass% or less, Mn: 0.01 mass are particularly preferable. %, Mg: 0.01% by mass or less, Cr: 0.01% by mass or less, Zn: 0.01% by mass or less, Ti: 0.02% by mass or less, Al: 99.5% by mass or more It is a board.

  Regarding the JIS 1050 material, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Application Laid-Open Nos. 59-153861, 61-51395, 62-146694, 60-215725, and 60-215725. JP 60-215726, JP 60-215727, JP 60-216728, JP 61-272367, JP 58-11759, JP 58-42493, JP 58- 221254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3-234594, JP-B-1-47545, and JP-A-62. It is described in each publication of -140894. In addition, techniques described in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.

  Regarding the JIS1070 material, the techniques proposed by the applicant of the present application are disclosed in JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108659 and It is described in JP-A-8-92679.

  Regarding Al-Mg alloys, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Publication Nos. Sho 62-5080, Sho 63-60823, Shoko 3-61753, JP Sho 60-20396, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-23794, JP-A-63-47347, JP-A-63-47348, JP-A-63-47349. JP-A 64-1293, JP-A 63-135294, JP-A 63-87288, JP-B 4-73392, JP-B 7-100844, JP-A 62-149856, JP-B JP-A-4-73394, JP-A-62-181191, JP-B-5-76530, JP-A-63-30294, and JP-B-6-37116. Also described in JP-A-2-215599, JP-A-61-201747, and the like.

  With regard to Al—Mn alloys, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 60-230951, 1-306288, and 2-293189. In addition, JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992, JP-A-4-19592, No. 226394, US Pat. No. 5,009,722, US Pat. No. 5,028,276 and the like.

  With regard to the Al—Mn—Mg alloy, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 62-86143 and 3-2222796. JP-B 63-60824, JP-A 60-63346, JP-A 60-63347, JP-A-1-293350, European Patent No. 223,737, US Pat. No. 4,818, No. 300, British Patent No. 1,222,777, etc.

  Regarding the Al—Zr alloy, the technique proposed by the applicant of the present application is described in Japanese Patent Publication No. 63-15978 and Japanese Patent Application Laid-Open No. 61-51395. Also described in JP-A-63-143234 and JP-A-63-143235.

  The Al—Mg—Si alloy is described in British Patent 1,421,710.

  In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter that uses alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or a combination of a degassing process and a filtering process is performed.

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The present applicant has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. Regarding the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. When the temperature is less than 1 ° C., many coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be manufactured. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient. In addition, when soaking is not performed, there is an advantage that the cost can be reduced.

  Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.

Among the above processes, in the cold rolling process, a plurality of passes are rolled to be processed into a predetermined plate thickness. At that time, using a roll having irregularities on the surface at the final pass, AL is used. An arbitrary surface roughness (R _a ) is transferred to the plate surface. Here the surface roughness of the plate thickness has an arithmetic mean roughness R _a = 0.5 to 1.0 [mu] m, and finished to a thickness = 0.1 to 0.5 mm.
Thereafter, the flatness of the aluminum plate may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve the productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a double belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. Regarding the intermediate annealing condition and the cold rolling condition when using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, It is described in JP-A-8-92709.

Various characteristics described below are desired for the aluminum plate thus manufactured.
The strength of the aluminum plate is preferably such that the 0.2% proof stress is 120 MPa or more in order to obtain the stiffness required for a lithographic printing plate support. Further, in order to obtain a certain level of waist strength even when performing a burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and 100 MPa or more. It is more preferable that In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used, but if the waist is strengthened, the ease of fitting to the plate cylinder of a printing press becomes inferior. Depending on the application, the material and the amount of trace components added are appropriately selected. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 7-126820 and 62-140894.
The aluminum plate preferably has a tensile strength of 160 ± 15 N / mm ² , a 0.2% proof stress of 140 ± 15 MPa, and an elongation specified by JIS Z2241 and Z2201 of 1 to 10%.

The aluminum plate used in the present invention is obtained by transferring a concavo-convex shape using a roughened roll, and has a micro-bulged portion and concavo-convex with an arithmetic average roughness _Ra of 0.5 to 1.0 μm on the surface. Have.
Here, the micro-protrusion is an uneven plastic deformation part (flap) formed on the surface of the aluminum plate by the transfer of the roughened roll, and a part of the aluminum produced by friction with a pass roll or the like. A small piece (AL small piece) is said, and when there is no AL small piece on the aluminum plate surface, it means only a flap. FIG. 1 is a schematic diagram for explaining an uneven shape on the surface of an aluminum plate.
As shown in FIG. 1A, the aluminum plate surface has an oval recess 32 and an Al piece 34. Specifically, as shown in FIGS. 1B to 1D, when a concavo-convex shape is transferred to a surface of an aluminum plate 30 using a roughened roll 31, the convex portions on the surface of the roll 31 are made of aluminum. When coming into contact with the plate 30 (FIG. 1C) and then withdrawing (FIG. 1D), the unevenness transferred to the aluminum plate 30 undergoes plastic deformation, and a flap 33 is formed in the oval recess 32. The Further, the AL small piece 34 is a part of the AL 33 that is broken away and attached to the aluminum plate surface when the flap 33 receives friction.

In the present invention, the step of forming irregularities by transferring a roll is not particularly limited, but it is preferable to perform rolling using a rolling roll. When unevenness is formed by rolling, energy consumed in the subsequent alkali etching process and roughening process can be reduced, and the amount of dampening water on the printing press can be easily adjusted. Thus, a uniform concavo-convex pattern can be easily obtained, and a lithographic printing plate precursor having improved sensitivity, stain resistance and printing durability can be obtained.
Further, in the present invention, it is particularly preferable that the transfer with the roughened roll is performed in the final cold rolling step of an ordinary aluminum plate. Rolling for transfer is preferably performed in 1 to 3 passes, and the rolling reduction is preferably 3 to 8%.

Examples of a method for obtaining a rolling roll that is preferably used for transferring uneven shapes include, for example, a method of subjecting the surface of a steel roll to a surface roughening treatment by shot blasting or sand blasting, a method of polishing with a grindstone or paper containing abrasive grains, Examples include a method of generating a dent by irradiating a laser, a method of generating irregularities by electric discharge machining, a method of performing chemical surface roughening treatment or electrolytic surface roughening treatment, and the like.
The roughening treatment by shot blasting or sand blasting may be wet or dry. In the case of performing chemical surface roughening treatment or electrolytic surface roughening treatment, after applying a resist, exposure and development are performed to form a pattern, and etching treatment can be performed to obtain the pattern.

After obtaining the rolling roll by the method described above, it is preferable to harden by quenching, hard chrome plating or the like in order to prevent surface abrasion.
Specifically, the surface of the steel roll is provided with irregularities by wet shot blasting, then a direct current is passed in a hard chrome plating bath, and the roll side becomes the anode in the range of 1 minute to 1 hour (roll +) To provide fine irregularities on the surface. Immediately reverse the DC current +-, the roll side becomes the cathode (roll is-), and the plating is grown on the surface for 0.5-10 hours; hard chrome plating on the surface of the steel roll A method of forming regular irregularities on the surface by performing polishing finish on the surface and further intermittently irradiating the YAG laser on the circumference of the roll is preferably exemplified.

  Other methods for obtaining the rolling roll include, for example, JP-A-60-36195, JP-A-2002-251005, JP-A-60-203495, JP-A-55-74898, and JP-A-62-111792. The methods described in each of the above publications can be used.

It is preferable that the aluminum plate on which the concavo-convex shape is transferred using such a rolling roll has a structure having concavo-convex of 1 to 100 μm pitch on the surface.
In this case, the arithmetic average roughness _Ra is 0.5 to 1.0 [mu] m, and preferably 0.5 to 0.8 [mu] m.
Also, maximum height (R _max) is preferably from 1 to 6 m, and more preferably 2 to 5 [mu] m.
The average distance of the unevenness (RS _m) is preferably from 10 to 150 m, and more preferably 20 to 100 [mu] m.
The number of concave portions (pits) on the surface is preferably ²⁰⁰ to 40000 pieces / mm ² . An oval concave portion is formed by the transfer, and the average aspect ratio (major axis / minor axis length) is preferably 1 to 4, particularly 1.5 to 2.5.

Measurement methods such as arithmetic mean roughness R _a of the surface of the aluminum plate, stylus roughness meter (e.g., Sufcom575, manufactured by Tokyo Seimitsu Co., Ltd.) subjected to two-dimensional roughness measurement, the arithmetic average roughness as defined in ISO4287 The thickness _Ra was measured 5 times, and the average value was calculated.

<Surface treatment>
The method for producing a lithographic printing plate support according to the present invention comprises at least the above-described micro-bulge on an aluminum plate having a micro-bulge and irregularities having an arithmetic average roughness _Ra of 0.5 to 1.0 μm on the surface. some or all removed parts, pretreatment to reduce the arithmetical mean roughness R _a of the unevenness of the aluminum plate, and subjected to electrolytic surface roughening treatment in this order, to obtain a lithographic printing plate support It is.
In the present invention, it is preferable that the aluminum plate described above is subjected to nitric acid alternating current electrolysis and / or hydrochloric acid alternating current electrolysis as the electrolytic surface-roughening treatment, followed by an anodic oxidation treatment. Moreover, you may perform the etching process in aqueous alkali solution, the desmut process in aqueous acid solution, etc. as needed between the said electrolytic surface-roughening process and anodizing process. Further, after the anodizing treatment, a sealing treatment and a hydrophilization treatment may be performed.
Hereinafter, each step of the surface treatment will be described in detail.

<Pretreatment>
In the present invention, _a pretreatment is performed to remove a part or all of the minute ridges present on the surface of the aluminum plate and to reduce the arithmetic average roughness Ra of the unevenness of the aluminum plate.

Preprocessing, after performing 5 times or more repetitive bending process on the aluminum plate, a process of performing chemical etching using an alkaline solution. By bending the aluminum plate in advance, it is possible to suppress a reduction in the thickness of the aluminum plate without reliably breaking the uniform uneven shape transferred to the surface of the aluminum plate by the roughened roll.
Here, the repeated bending process refers to a process of repeating the process of alternately bending the uneven surface of the aluminum plate outward and inward, for example, a process of rolling the aluminum plate to a plurality of rolls. Specifically, as the repeated bending treatment of 5 times or more, a method of alternately rolling the front and back surfaces of an aluminum plate to 10 or more rolls at a wrap angle of 170 ° or more (hereinafter referred to as “rolling method to roll”). It is also referred to as a suitable example. In this method of rolling contact with the roll, the state in which the uneven surface of the aluminum plate and the opposite surface (back surface) are each in contact with the roll once is subjected to one repeated bending treatment. Therefore, repeated bending treatment is performed 5 times or more by rolling contact with 10 or more rolls. By performing this repeated bending process five times or more, it is possible to raise the AL pieces that are in close contact with the aluminum surface and the flaps that are likely to be peeled off and separated by friction or the like. The minute ridges are easily removed by the selective etching process.
Moreover, the chemical etching process using the alkali solution after a repetition process means the process which melt | dissolves a surface layer by making the aluminum plate which performed the repetition process 5 times or more contact an alkali solution. Examples of the alkaline solution used for this chemical etching treatment include those exemplified in the first alkali etching treatment described later. In the present invention, the etching amount of the chemical etching treatment is preferably a 0.5~6g / m ^2, and more preferably 1 to 3 g / m ^2. Furthermore, in the present invention, in this chemical etching treatment, the concentration of the alkaline solution is preferably 50 g / L or more, more preferably 400 g / L or less, and 300 g / L or less. Is more preferable.

In the present invention, by performing the pretreatment, a part or all of the minute ridges are removed. Further, the pre-processing is intended to reduce an arithmetic mean roughness R _a of the unevenness of the aluminum plate, irregularities of the aluminum plate surface after the pretreatment, unevenness by the transfer rolls roughened as described above The shape is maintained. Specifically, the arithmetic mean roughness R _a of the unevenness of the surface of the aluminum plate after the above pretreatment is not more than the arithmetic mean roughness R _a of the unevenness due to the transfer of the roughened roll, from 0.3 to 0 .9μm and ing. When the arithmetic average roughness _Ra is within this range, the lithographic printing plate obtained using the pretreated aluminum plate is also excellent in the shininess that damps the visibility of the printing surface after dampening water dampening water. . From the viewpoint of more excellent shiny property, the arithmetic average roughness _Ra is more preferably 0.4 μm or more, and further preferably 0.5 μm or more.

<First alkali etching treatment>
In the present invention, it is preferable to subject the pretreated aluminum plate to a first alkali etching treatment.
The alkali etching treatment refers to a treatment for dissolving the surface layer by bringing the above-described aluminum plate into contact with an alkaline solution. The first alkali etching treatment performed before the electrolytic surface roughening treatment is uniform by the electrolytic surface roughening treatment. For the purpose of forming a concave portion and removing rolling oil, dirt, natural oxide film and the like on the surface of an aluminum plate (rolled aluminum).
In the first alkali etching treatment, the etching amount is preferably 0.1 g / m ² or more, more preferably 1 g / m ² or more, and further preferably 3 g / m ² or more. Further, it is preferably 10 g / m ² or less, more preferably 8 g / m ² or less, further preferably 6 g / m ² or less, and further preferably 3 g / m ² or less. If the etching amount is too small, uniform pits cannot be generated in AC electrolysis and unevenness may occur. On the other hand, when there is too much etching amount, the usage-amount of alkaline aqueous solution will increase and it will become economically disadvantageous.

  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.

In the first alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

  In the first alkali etching treatment, the temperature of the alkaline solution is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, and 75 ° C. or lower. Is more preferable.

  In the first alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 15 seconds or shorter. preferable.

When the aluminum plate is continuously etched, the aluminum ion concentration in the alkaline solution increases and the etching amount of the aluminum plate varies. Therefore, the composition management of the etching solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature corresponding to the matrix of caustic soda concentration and aluminum ion concentration is prepared in advance, and the conductivity and specific gravity are prepared. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and caustic soda and water are added so that the control target value of the liquid composition is reached. Then, the amount of the etching solution increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the amount of the solution constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.

  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.

  Among these, a method in which an alkali solution is sprayed on the surface of an aluminum plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the alkali etching process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds and then drain the liquid with a nip roller.
The water washing treatment is preferably carried out using an apparatus for washing with a free-falling curtain-like liquid film, and further using a spray tube.

If an apparatus for washing with a free fall curtain-like liquid film as shown in FIG. 2 is used, the aluminum plate can be uniformly washed with water, so that the uniformity of the treatment performed before the washing process can be improved. Can be improved.
As a specific apparatus for washing with a free-fall curtain-like liquid film, for example, an apparatus described in JP-A-2003-96584 is preferably exemplified.

  Moreover, as a spray tube used for the water-washing process, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum plate in which spray water spreads in a fan shape can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 0.5 to 20 L / min. It is preferable to use a plurality of spray tubes.

<First desmut treatment>
In the present invention, it is preferable to perform pickling (first desmutting treatment) after removing the first alkali etching treatment as desired in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing an aluminum plate into contact with an acidic solution.

Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. As the desmut treatment liquid, the overflow waste liquid from the anodizing treatment step can be used.
In the first desmut process performed after the first alkali etching process, it is preferable to use an overflow waste liquid of an electrolyte solution used in the subsequent nitric acid AC electrolysis.

  In the composition management of the desmut treatment liquid, a method of managing by conductivity and temperature, a method of managing by conductivity, specific gravity and temperature, and a conductivity and superconductivity corresponding to a matrix of acidic solution concentration and aluminum ion concentration. Either of the methods managed by the propagation speed of sound waves and temperature can be selected and used.

  In the first desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L of acid and 0.1 to 5 g / L of aluminum ions.

  The temperature of the acidic solution is preferably 20 ° C. or more, more preferably 30 ° C. or more, and preferably 70 ° C. or less, more preferably 60 ° C. or less.

In the first desmutting treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 40 seconds or shorter. .

Examples of the method of bringing the aluminum plate into contact with the acidic solution include a method in which the aluminum plate is passed through a tank containing the acidic solution, a method in which the aluminum plate is immersed in a tank containing the acidic solution, and the acidic solution being aluminum. The method of spraying on the surface of a board is mentioned.
Among these, a method in which an acidic solution is sprayed on the surface of an aluminum plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having holes of φ2 to 5 mm at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.

  In the first desmut process, when using the overflow waste liquid of the electrolyte used in the subsequent nitric acid alternating current electrolysis as the desmut process liquid, after the desmut process, the nip roller is not drained and washed with water. In order to prevent the surface from drying, it is preferable to handle the aluminum plate until the nitric acid alternating current electrolysis step while spraying a desmut treatment liquid as necessary.

<Nitric acid AC electrolysis>
In the present invention, the electrolytic surface-roughening treatment is performed after the pretreatment or the first alkali etching or the first desmut treatment performed as desired. Specific examples of the electrolytic surface roughening treatment include nitric acid alternating current electrolysis and hydrochloric acid alternating current electrolysis.
Further, in the present invention, it is preferable to perform both nitric acid alternating current electrolysis and hydrochloric acid alternating current electrolysis, and in the case of performing any treatment, it is preferable to perform hydrochloric acid alternating current electrolysis described later after performing nitric acid alternating current electrolysis first. .

  Nitric acid alternating current electrolysis is an electrochemical surface roughening treatment using alternating current in an aqueous solution containing nitric acid. A suitable uneven structure can be formed on the surface of the aluminum plate by nitric acid AC electrolysis.

  Nitric acid alternating current electrolysis can follow, for example, the 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, including US Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP 53-32821, JP 53-32222, JP 53-32823, JP 55-122896, JP 55-13284, JP 62-127500, JP Those described in 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.

An aqueous solution containing nitric acid is added to an aqueous nitric acid solution having a concentration of 1 to 100 g / L in a range from 1 g / L to saturation with at least one of nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, and ammonium nitrate. Can be used. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing nitric acid.
Specifically, a solution prepared by dissolving aluminum nitrate in an aqueous nitric acid solution having a nitric acid concentration of 5 to 15 g / L and adjusting the aluminum ion concentration to 3 to 7 g / L is preferable.

When the electrolytic roughening treatment is continuously performed on the aluminum plate, the aluminum ion concentration in the alkaline solution increases, and the uneven shape of the aluminum plate formed by nitric acid AC electrolysis varies. Therefore, it is preferable to manage the composition of the nitric acid electrolyte as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature, corresponding to the matrix of nitric acid concentration and aluminum ion concentration, is prepared in advance, and the conductivity and specific gravity are prepared. And the temperature, or the liquid composition is measured according to the electric conductivity, the ultrasonic wave propagation speed, and the temperature, and nitric acid and water are added so that the control target value of the liquid composition is reached. Then, the electrolytic solution increased by adding nitric acid and water is overflowed from the circulation tank, so that the liquid amount is kept constant. As nitric acid to be added, 30 to 70% by mass of industrial grade can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measuring the liquid composition are used for measurement after being controlled at a constant temperature (eg, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

  The temperature of the aqueous solution containing nitric acid is preferably 10 ° C or higher, particularly 30 ° C or higher, and preferably 90 ° C or lower, particularly 55 ° C or lower.

  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 0.5 to 3 msec. When TP exceeds 3 msec, especially when an aqueous solution containing nitric acid is used, it becomes susceptible to the influence of trace components in the electrolytic solution typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining. Is difficult to be performed. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

A trapezoidal wave alternating current duty ratio 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 ratio of 1: 1 is preferable.
A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is likely to be affected by the inductance component on the power supply circuit and the power supply cost is increased.

FIG. 4 is a side view showing an example of a radial type cell used for electrochemical surface roughening treatment using alternating current, which is used in an example of the method for producing a lithographic printing plate support of the present invention.
One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 4, 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. 4, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment solution, 15 is an electrolyte 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 separate tank 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.

Pits having an average opening diameter of 0.5 to 5 μm can be formed by nitric acid AC electrolysis. 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 at 150C / dm ² or more, at 170C / dm ² or more more preferably, but preferably not 400C / dm ² or less, more preferably 300C / dm ² or less. The current density at this time is preferably ²⁰ to 100 A / dm ² at the peak value of the current. The liquid temperature is preferably 10 ° C or higher, particularly 30 ° C or higher, 90 ° C or lower, particularly 70 ° C or lower.

After the nitric acid AC electrolysis is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing treatment for 1 to 10 seconds and then drain the liquid with a nip roller.
The washing treatment is preferably carried out using a spray tube. As the spray tube used for the water washing treatment, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum plate in which fan water spreads in a fan shape can be used. The interval between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

If the following pre-electrolysis is performed before nitric acid alternating current electrolysis, deep concave portions are not formed in nitric acid alternating current electrolysis, and uniform concave portions can be formed.
Pre-electrolysis is a step of forming the starting point of pit formation during nitric acid AC electrolysis. By performing slight electrolysis using hydrochloric acid which is not easily affected by the material of the aluminum plate and is highly corrosive, pits can be formed uniformly on the surface.
In pre-electrolysis, the hydrochloric acid concentration is preferably 1 to 15 g / L, and the amount of electricity at the time of anode is preferably 30 to 70 C / m ² .
After pre-electrolysis, it is preferable to perform alkali etching to remove smut. The amount of aluminum dissolved in the alkali etching is preferably 0.2 to 0.6 g / m ² .

<Second alkali etching treatment>
In this invention, it is preferable to perform a 2nd alkali etching process between the said nitric acid alternating current electrolysis and the hydrochloric acid alternating current electrolysis mentioned later.
This second alkali etching treatment is performed for the purpose of dissolving the smut generated by nitric acid alternating current electrolysis and dissolving the edge portion of the pit formed by nitric acid alternating current electrolysis. The second alkali etching process is basically the same as the first alkali etching process, and only the differences will be described below.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. If the etching amount is too small, the edge portion of the pit generated by nitric acid AC electrolysis is not smooth in the non-image portion of the lithographic printing plate, and the ink is likely to get caught, so that the stain resistance may be deteriorated. On the other hand, if the etching amount is too large, the unevenness generated by nitric acid AC electrolysis is reduced, so that the printing durability may be deteriorated.

In the second alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

  In the second alkali etching treatment, the temperature of the alkaline solution is preferably 30 ° C or higher, more preferably 35 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.

  In the second alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

<Second desmut treatment>
In the present invention, it is preferable to perform pickling (second desmut treatment) after removing the second alkali etching treatment as desired in order to remove dirt (smut) remaining on the surface.
Since the second desmut process is basically the same as the first desmut process, only different points will be described below.

In the second desmut treatment, nitric acid, hydrochloric acid, sulfuric acid or the like can be used, but nitric acid or sulfuric acid is preferably used.
In the second desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.5 to 8 g / L aluminum ions. When sulfuric acid is used, a treatment liquid in which aluminum sulfate is dissolved in an acid having a sulfuric acid concentration of 100 to 350 g / L to have an aluminum ion concentration of 0.1 to 5 g / L can be used.
In the second desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, and 20 seconds or shorter. More preferred.

<Hydrochloric acid alternating current electrolysis>
In the present invention, the electrolytic surface roughening treatment is performed. As described above, it is preferable to perform hydrochloric acid alternating current electrolysis after the nitric acid alternating current electrolysis.
Hydrochloric acid alternating current electrolysis is an electrochemical surface roughening treatment using alternating current in an aqueous solution containing hydrochloric acid. A suitable concavo-convex structure can be formed on the surface of the aluminum plate by hydrochloric acid alternating current electrolysis, and the lithographic printing plate using the obtained support is excellent in printing durability.

  Hydrochloric acid AC electrolysis can be carried out in substantially the same manner as the above-described nitric acid AC electrolysis except that the electrolytic solution is different. Only different points will be described below.

The aqueous solution containing hydrochloric acid is an aqueous solution of hydrochloric acid having a concentration of 1 to 100 g / L, in a range from 1 g / L to saturation of at least one hydrochloric acid compound having hydrochloric acid ions such as aluminum chloride, sodium chloride, and ammonium chloride. It can be used by adding. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing hydrochloric acid.
Specifically, a solution prepared by dissolving aluminum chloride in an aqueous nitric acid solution having a hydrochloric acid concentration of 2 to 10 g / L to adjust the aluminum ion concentration to 3 to 7 g / L is preferable.

  The temperature of the aqueous solution containing hydrochloric acid is preferably 25 ° C. or higher, more preferably 30 ° C. or higher, more preferably 55 ° C. or lower, and even more preferably 40 ° C. or lower.

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. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is preferably 10 C / dm ² or more, more preferably 50 C / dm ² or more. Is more preferably 100 C / dm ² or less, and more preferably 80 C / dm ² or less. The current density at this time is preferably ²⁰ to 100 A / dm ² at the peak value of the current.

When the aluminum plate is continuously subjected to electrolytic surface roughening, the concentration of aluminum ions in the alkaline solution increases, and the uneven shape of the aluminum plate formed by hydrochloric acid AC electrolysis varies. Therefore, it is preferable to manage the composition of the hydrochloric acid electrolyte as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature, corresponding to the matrix of hydrochloric acid concentration and aluminum ion concentration, is prepared in advance, and the conductivity and specific gravity. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and hydrochloric acid and water are added so that the control target value of the liquid composition is reached. Then, the electrolytic solution increased by adding hydrochloric acid and water is allowed to overflow from the circulation tank, thereby keeping the amount of the solution constant. As hydrochloric acid to add, the industrial thing of 10-40 mass% can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measurement of the liquid composition are used for measurement after being controlled at a constant temperature (for example, 35 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

<Third alkali etching treatment>
In the present invention, it is preferable to perform a third alkali etching treatment after the hydrochloric acid alternating current electrolysis.
The third alkali etching treatment is performed for the purpose of dissolving smut generated by hydrochloric acid alternating current electrolysis and dissolving the edge portion of the pit formed by hydrochloric acid alternating current electrolysis. Since the third alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the third alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, is 0.3 g / m ² or less Of 0.25 g / m ² or less is more preferable. When the etching amount is too small, the edge portion of the pit generated by hydrochloric acid alternating current electrolysis is not smooth in the non-image portion of the lithographic printing plate, and the ink is likely to get caught, so that the stain resistance may be deteriorated. On the other hand, if the etching amount is too large, the unevenness generated by nitric acid alternating current electrolysis and hydrochloric acid alternating current electrolysis becomes small, so the printing durability may deteriorate.

In the third alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, and in order not to make the unevenness caused by the hydrochloric acid alternating current electrolysis in the previous stage too small, the concentration is 100 g / L or less. It is preferable that it is 70 g / L or less.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, preferably 50 g / L or less, more preferably 8 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

  In the third alkali etching treatment, the temperature of the alkali solution is preferably 25 ° C or higher, more preferably 30 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.

  In the third alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

<Third desmut treatment>
In the present invention, it is preferable to perform pickling (third desmut treatment) after the third alkali etching treatment, which is performed as desired, in order to remove dirt (smut) remaining on the surface.
Since this third desmut process is basically the same as the first desmut process, only the differences will be described below.

In the third desmutting process, the same type of liquid as that used in the subsequent anodizing process (for example, sulfuric acid) is used, thereby omitting the water washing step between the third desmutting process and the anodizing process. It is preferable in that it can be performed.
In the third desmutting treatment, it is preferable to use an acidic solution containing 5-400 g / L acid and 0.5-8 g / L aluminum ions. A treatment liquid in which aluminum sulfate is dissolved in an acid having a sulfuric acid concentration of 100 to 350 g / L to have an aluminum ion concentration of 0.1 to 5 g / L can be used.
In the third desmutting treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, more preferably 60 seconds or shorter, and more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of liquid as the electrolyte used in the subsequent anodizing process is used as the desmut process liquid, the draining with a nip roller and the water washing process can be omitted after the desmut process.

<Anodizing treatment>
It is preferable that the aluminum plate treated as described above is further subjected to an anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an aluminum plate can be energized as an anode to form an anodized film. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. ˜60 A / dm ² , voltage 1 to 100 V, and electrolysis time 15 seconds to 50 minutes are appropriate and adjusted so as to obtain a desired anodic oxide film amount.

  Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), more preferably 50 to 200 g / L (5 to 20% by mass), and the aluminum ion concentration. Is preferably 1 to 25 g / L (0.1 to 2.5% by mass), more preferably 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

  The composition management of the electrolytic solution is conducted using the same method as in the case of the above-described nitric acid alternating current electrolysis, etc., and the conductivity, specific gravity and temperature, or the conductivity and ultrasonic wave corresponding to the matrix of sulfuric acid concentration and aluminum ion concentration. It is preferable to control by the propagation speed and temperature.

  The liquid temperature of the electrolytic solution is preferably 25 to 55 ° C, more preferably 30 to 50.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, whereas if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable that the difference in the amount of the anodized film between the central portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.

  As electrolysis apparatuses used for anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, JP-A-2001-11698, etc. Can be used.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, even if the sealing treatment is carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Hydrophilic treatment>
In the present invention, a hydrophilization treatment may be performed after an anodizing treatment or a sealing treatment to be applied as desired. 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 a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a primer layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

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.

  Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. It is preferable to carry out the treatment.

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.

The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² .
By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.

<Dry>
After obtaining the lithographic printing plate support as described above, it is preferable to dry the surface of the lithographic printing plate support before providing the image recording layer. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 2 to 15 seconds.

[Lithographic printing plate precursor]
The lithographic printing plate support obtained by the present invention can be provided with an image recording layer to form the lithographic printing plate precursor of the present invention. A photosensitive composition is used for the image recording layer.
Examples of the photosensitive composition suitably used in the present invention include a thermal positive photosensitive composition containing an alkali-soluble polymer compound and a photothermal conversion substance (hereinafter, this composition and an image recording layer using the same). ), A thermal negative photosensitive composition containing a curable compound and a photothermal conversion substance (hereinafter also referred to as “thermal negative type”), a photopolymerizable photosensitive composition (hereinafter referred to as “thermal positive type”). , Also referred to as “photopolymer type”), negative photosensitive composition containing diazo resin or photocrosslinking resin (hereinafter also referred to as “conventional negative type”), and positive photosensitive composition containing quinonediazide compound. Product (hereinafter also referred to as "conventional positive type"), photosensitive composition that does not require a special development step (hereinafter referred to as Referred to as "non-treatment type".) It can be mentioned as, in particular, thermal positive type, thermal negative type, non-treatment type is preferred. Hereinafter, these suitable photosensitive compositions will be described.

<Thermal positive type>
<Photosensitive layer>
The thermal positive type photosensitive composition contains an alkali-soluble polymer compound and a photothermal conversion substance. In the thermal positive type image recording layer, the photothermal conversion substance converts the energy of light such as infrared lasers into heat, which effectively eliminates the interaction that reduces the alkali solubility of alkali-soluble polymer compounds. To do.

Examples of the alkali-soluble polymer compound include a resin containing an acidic group in the molecule and a mixture of two or more thereof. In particular, a phenolic hydroxy group, sulfonamide group (in -SO ₂ NH-R (wherein, R represents a hydrocarbon group.)), Active imino group _{(-SO 2 NHCOR, -SO 2 NHSO} 2 R, -CONHSO A resin having an acidic group such as ₂ R (wherein R has the same meaning as described above) is preferable in terms of solubility in an alkali developer.
In particular, a resin having a phenolic hydroxy group is preferable in that it has excellent image-forming properties when exposed to light such as an infrared laser, and examples thereof include phenol-formaldehyde resins, m-cresol-formaldehyde resins, p-cresol-formaldehyde resins, m- / p-mixed cresol-formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) mixed-formaldehyde resin (phenol-cresol-formaldehyde co-condensation resin) and other novolak resins Are preferable.
Furthermore, a polymer compound described in JP-A No. 2001-305722 (particularly [0023] to [0042]), and a repetition represented by the general formula (1) described in JP-A No. 2001-215893 Preferred examples also include polymer compounds containing units, and polymer compounds described in JP-A No. 2002-311570 (particularly [0107]).

  Preferable examples of the photothermal conversion substance include pigments or dyes having a light absorption region in the infrared region having a wavelength of 700 to 1200 nm in terms of recording sensitivity. Examples of the dye include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes (for example, , Nickel thiolate complex). Among these, cyanine dyes are preferable, and cyanine dyes represented by the general formula (I) described in JP 2001-305722 A are particularly preferable.

The thermal positive type photosensitive composition can contain a dissolution inhibitor. As the dissolution inhibitor, for example, dissolution inhibitors described in JP-A-2001-305722, [0053] to [0055] are preferably exemplified.
In addition, in the thermal positive type photosensitive composition, as a additive, a sensitivity modifier, a printing agent for obtaining a visible image immediately after heating by exposure, a compound such as a dye as an image colorant, a coating property In addition, it is preferable to include a surfactant for improving the processing stability. For these, compounds as described in [0056] to [0060] of JP-A No. 2001-305722 are preferable.
The photosensitive composition described in detail by Unexamined-Japanese-Patent No. 2001-305722 is preferably used also in respects other than the above.

Further, the thermal positive type image recording layer is not limited to a single layer but may have a two-layer structure.
As an image recording layer having a two-layer structure (multilayer image recording layer), a lower layer (hereinafter referred to as “A layer”) having excellent printing durability and solvent resistance is provided on the side close to the support, and a positive layer is provided thereon. A type provided with a layer having excellent image formability (hereinafter referred to as “B layer”) is preferable. This type has high sensitivity and can realize a wide development latitude. The B layer generally contains a photothermal conversion substance. Preferred examples of the photothermal conversion substance include the dyes described above.
As the resin used for the A layer, a polymer having a monomer having a sulfonamide group, an active imino group, a phenolic hydroxy group or the like as a copolymerization component is preferably used because it has excellent printing durability and solvent resistance. . As the resin used for the B layer, an alkaline aqueous solution-soluble resin having a phenolic hydroxy group is preferably exemplified.
In addition to the resin, the composition used for the A layer and the B layer can contain various additives as necessary. Specifically, various additives as described in [0062] to [0085] of JP-A-2002-3233769 are preferably used. Further, the additives described in [0053] to [0060] of JP-A-2001-305722 described above are also preferably used.
About each component which comprises A layer and B layer, and its content, it is preferable to make it describe in Unexamined-Japanese-Patent No. 11-218914.

<Intermediate layer>
It is preferable to provide an intermediate layer between the thermal positive type image recording layer and the support. As the component contained in the intermediate layer, various organic compounds described in [0068] of JP-A No. 2001-305722 are preferably exemplified.

<Others>
As a method for producing a thermal positive type image recording layer and a plate making method, methods described in detail in JP-A No. 2001-305722 can be used.

<Thermal negative type>
The thermal negative photosensitive composition contains a curable compound and a photothermal conversion substance. The thermal negative type image recording layer is a negative photosensitive layer in which a portion irradiated with light such as an infrared laser is cured to form an image portion.
<Polymerized layer>
As one of the thermal negative type image recording layers, a polymerization type image recording layer (polymerization layer) is preferably exemplified. The polymerization layer contains a photothermal conversion substance, a radical generator, a radical polymerizable compound that is a curable compound, and a binder polymer. In the polymerization layer, infrared light absorbed by the light-to-heat conversion substance is converted into heat, the radical generator is decomposed by this heat to generate radicals, and the radical polymerizable compound is polymerized in a chain by the generated radicals and cured. .

As a photothermal conversion substance, the photothermal conversion substance used for the thermal positive type mentioned above is mentioned, for example. Specific examples of particularly preferred cyanine dyes include those described in JP-A-2001-133969, [0017] to [0019].
Preferable examples of the radical generator include onium salts. In particular, onium salts described in JP-A-2001-133969, [0030] to [0033] are preferable.
Examples of the radically polymerizable compound include compounds having at least one terminal ethylenically unsaturated bond, preferably two or more.
As the binder polymer, a linear organic polymer is preferably exemplified. Preferable examples include linear organic polymers that are soluble or swellable in water or weak alkaline water. Among them, a (meth) acrylic resin having an unsaturated group such as an allyl group or an acryloyl group or a benzyl group and a carboxy group in the side chain is preferable in that it has an excellent balance of film strength, sensitivity, and developability. .
As the radical polymerizable compound and the binder polymer, those described in detail in [0036] to [0060] of JP-A No. 2001-133969 can be used.

  The additive described in [0061] to [0068] of JP-A No. 2001-133969 is contained in the thermal negative photosensitive composition (for example, a surfactant for improving coatability). Is preferred.

  As a method for producing the polymerization layer and a plate making method, methods described in detail in JP-A No. 2001-133969 can be used.

<Acid cross-linked layer>
Further, as one of the thermal negative type image recording layers, an acid cross-linked image recording layer (acid cross-linked layer) is also preferably exemplified. The acid crosslinking layer comprises a photothermal conversion substance, a thermal acid generator, a compound that crosslinks with an acid that is a curable compound (crosslinking agent), and an alkali-soluble polymer compound that can react with the crosslinking agent in the presence of an acid. contains. In the acid cross-linking layer, infrared light absorbed by the light-to-heat conversion substance is converted into heat, and the thermal acid generator is decomposed by this heat to generate an acid, and the generated acid reacts with the cross-linking agent and the alkali-soluble polymer compound. And harden.

Examples of the photothermal conversion substance include the same substances as those used for the polymerization layer.
Examples of the thermal acid generator include thermal decomposition compounds such as photoinitiators for photopolymerization, photochromic agents for dyes, and acid generators used in microresists.
Examples of the crosslinking agent include an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group; a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group; and an epoxy compound.
Examples of the alkali-soluble polymer compound include novolak resins and polymers having a hydroxyaryl group in the side chain.

<Photopolymer type>
The photopolymerization type photosensitive composition contains an addition polymerizable compound, a photopolymerization initiator, and a polymer binder.
As the addition polymerizable compound, an ethylenically unsaturated bond-containing compound capable of addition polymerization is preferably exemplified. The ethylenically unsaturated bond-containing compound is a compound having a terminal ethylenically unsaturated bond. Specifically, for example, it has a chemical form such as a monomer, a prepolymer, and a mixture thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, maleic acid) and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds. Is mentioned.
Moreover, as an addition polymerizable compound, a urethane type addition polymerizable compound is also preferably exemplified.

As the photopolymerization initiator, various photopolymerization initiators or a combination system (photoinitiation system) of two or more kinds of photopolymerization initiators can be appropriately selected depending on the wavelength of the light source to be used. For example, an initiation system described in JP-A-2001-22079, [0021] to [0023] is preferably exemplified.
The polymer binder not only functions as a film forming agent for the photopolymerization type photosensitive composition, but is soluble or swellable in alkaline water because the image recording layer needs to be dissolved in an alkaline developer. An organic high molecular polymer is used. As such an organic polymer, those described in JP-A-2001-22079, [0036] to [0063] are preferably exemplified.

  In the photopolymer type photopolymerization type photosensitive composition, additives described in JP-A-2001-22079, [0079] to [0088] (for example, a surfactant for improving coatability) , Colorants, plasticizers, thermal polymerization inhibitors).

Further, it is preferable to provide an oxygen-blocking protective layer on the photopolymer type image recording layer in order to prevent the action of inhibiting polymerization of oxygen. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and copolymers thereof.
Furthermore, it is also preferable to provide an intermediate layer or an adhesive layer as described in [0124] to [0165] of JP-A-2001-228608.

<Conventional negative type>
The conventional negative photosensitive composition contains a diazo resin or a photocrosslinking resin. Among them, preferred is a photosensitive composition containing a diazo resin and an alkali-soluble or swellable polymer compound (binder).
Examples of the diazo resin include a condensate of an aromatic diazonium salt and an active carbonyl group-containing compound such as formaldehyde; a condensate of p-diazophenylamines and formaldehyde with a hexafluorophosphate or a tetrafluoroborate. An organic solvent-soluble diazo resin inorganic salt which is a reaction product of In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable.
Examples of the binder include a copolymer containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential component. Specifically, multi-component copolymers of monomers such as 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, and (meth) acrylic acid as described in JP-A-50-118802, Examples thereof include multi-component copolymers composed of alkyl acrylate, (meth) acrylonitrile and unsaturated carboxylic acid as described in JP-A-56-4144.

  The conventional negative type photosensitive composition has, as an additive, a printing agent, dye, and flexibility and abrasion resistance described in JP-A-7-281425, [0014] to [0015]. It is preferable to contain a plasticizer for imparting, a compound such as a development accelerator, and a surfactant for improving coating properties.

  Under the conventional negative type photosensitive layer, an intermediate layer containing a polymer compound having a component having an acid group and a component having an onium group as described in JP-A-2000-105462 is provided. Is preferred.

<Conventional positive type>
The conventional positive type photosensitive composition contains a quinonediazide compound. Among these, a photosensitive composition containing an o-quinonediazide compound and an alkali-soluble polymer compound is preferable.
Examples of the o-quinonediazide compound include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, described in US Pat. No. 3,635,709. And esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin.
Examples of the alkali-soluble polymer compound include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, A carboxy group-containing polymer described in JP-A-7-36184, an acrylic resin containing a phenolic hydroxy group as described in JP-A-51-34711, and described in JP-A-2-866 Examples thereof include acrylic resins having a sulfonamide group and urethane resins.

  Conventional positive type photosensitive compositions include compounds such as sensitivity modifiers, printing agents, dyes and the like described in JP-A-7-92660, [0024] to [0027] as additives. It is preferable to contain a surfactant for improving the coating property as described in [0031] of Kaihei 7-92660.

  Under the conventional positive type photosensitive layer, it is preferable to provide an intermediate layer similar to the intermediate layer suitably used for the above-described conventional negative type.

<Non-treatment type>
Examples of the non-processing type photosensitive composition include a thermoplastic fine particle polymer type, a microcapsule type, and a sulfonic acid-generating polymer-containing type. These are all heat-sensitive types containing a photothermal conversion substance. The photothermal conversion substance is preferably the same dye as that used in the above-described thermal positive type.

The thermoplastic fine particle polymer type photosensitive composition is obtained by dispersing a hydrophobic and heat-meltable fine particle polymer in a hydrophilic polymer matrix. In the image recording layer of the thermoplastic fine particle polymer type, the hydrophobic fine particle polymer is melted by heat generated by exposure, and is fused to form a hydrophobic region, that is, an image portion.
As the fine particle polymer, those in which fine particles melt and coalesce with heat are preferable, and those having a hydrophilic surface and capable of being dispersed in a hydrophilic component such as dampening water are more preferable. Specifically, Research Disclosure No. 33303 (January 1992), JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, and JP-A-9-171250, and European Patent Application Publication No. 931,647. Preferred examples thereof include thermoplastic fine particle polymers. Of these, polystyrene and polymethyl methacrylate are preferred. Examples of the fine particle polymer having a hydrophilic surface include those in which the polymer itself is hydrophilic; those in which a hydrophilic compound such as polyvinyl alcohol and polyethylene glycol is adsorbed on the surface of the fine particle polymer to make the surface hydrophilic.
The fine particle polymer preferably has a reactive functional group.

  As a microcapsule type photosensitive composition, a compound having a heat-reactive functional group as described in JP-A No. 2000-118160 or JP-A No. 2001-277740 is included. A microcapsule type is preferable.

  Examples of the sulfonic acid generating polymer used in the sulfonic acid generating polymer-containing photosensitive composition include sulfonic acid ester groups, disulfone groups, and sec- or tert-sulfonamides described in JP-A No. 10-282672. Examples thereof include polymers having a group in the side chain.

  By incorporating a hydrophilic resin into the unprocessed photosensitive composition, not only on-press developability is improved, but also the film strength of the photosensitive layer itself is improved. Examples of the hydrophilic resin include those having a hydrophilic group such as hydroxy group, carboxy group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group, and hydrophilic sol-gel conversion system. A binder resin is preferred.

  The unprocessed type image recording layer does not require a special development step and can be developed on a printing press. As a method for producing an unprocessed image recording layer and a plate-making printing method, methods described in detail in JP-A No. 2002-178655 can be used.

<Back coat>
In this way, the backside of the lithographic printing plate precursor of the present invention obtained by providing various image recording layers on the lithographic printing plate support obtained by the present invention, if necessary, is an image in the case of overlapping. In order to prevent the recording layer from being damaged, a coating layer made of an organic polymer compound can be provided.

[Plate making method (lithographic printing plate production method)]
The lithographic printing plate precursor using the lithographic printing plate support obtained by the present invention is made into a lithographic printing plate by various treatment methods according to the image recording layer.
Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include a helium-neon laser (He-Ne laser), an argon laser, a krypton laser, a helium-cadmium laser, a KrF excimer laser, a semiconductor laser, a YAG laser, and a YAG-SHG laser.

After the above exposure, if the image recording layer is any of thermal positive type, thermal negative type, conventional negative type, conventional positive type, and photopolymer type, after exposure, it is developed using a developer to obtain a lithographic printing plate. It is preferable to obtain.
The developer is preferably an alkaline developer, and more preferably an alkaline aqueous solution substantially free of an organic solvent.
Moreover, the developing solution which does not contain alkali metal silicate substantially is also preferable. As a method for developing using a developer substantially not containing an alkali metal silicate, a method described in detail in JP-A-11-109637 can be used.
A developer containing an alkali metal silicate can also be used.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
1. Production of aluminum plate Molten metal using an aluminum alloy having a composition represented by Fe: 0.3 mass%, Si: 0.08 mass%, Cu: 500 ppm, Ti: 0.02 mass% (the balance being aluminum and inevitable impurities) Was prepared, a molten metal treatment and filtration were performed, and an ingot having a thickness of 500 mm and a width of 1200 mm was produced by a DC casting method. 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 treatment at 500 ° C. using a continuous annealing machine, cold rolling was performed to finish the film to a thickness of 0.3 mm and a width of 1060 mm to obtain an aluminum plate.
In addition, the uneven shape transfer is performed by pressing the uneven surface formed on the rolling roll produced by the following method in the cold rolling process to adjust the final thickness of the aluminum plate, An aluminum plate having unevenness with an average roughness _Ra of 0.55 μm on the surface was obtained.

<Production of rolling roll>
C: 1.52 mass%, Si: 0.31 mass%, Mn: 0.41 mass%, P: 0.028 mass%, S: 0.002 mass%, Cr: 11.6 mass%, Mo: 1.05% by mass, Cu: 0.12% by mass, V: 0.27% by mass, balance: SKD11 steel, which is an inevitable impurity, is hardened and tempered so that the hardness Hs becomes 82 The surface of the roll having a smooth surface with an average surface roughness _Ra of 0.1 μm was subjected to a surface roughening treatment by performing the wet shot blasting method twice. In the wet shot blasting method, alumina particles having an average particle size of 90 μm were used as the grid material, and the grid material was sprayed so that the angle with the spray surface was 90 °.
Then, direct current anode electrolysis was performed for 20 minutes and direct current cathode electrolysis for 60 minutes in a hard chromium plating solution so that the thickness was 10 μm, and a rolling roll having an _Ra of 0.6 μm was obtained.

2. Production of support for lithographic printing plate (Example 1 , Reference Example 2, Comparative Examples 1-3)
The aluminum plate obtained above was subjected to the following surface treatment to obtain each lithographic printing plate support shown in Table 1.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (a) to (k). In addition, after each surface-roughening process, the water washing process of the following conditions was performed, and the water draining was performed with the nip roller after the water washing process. The water washing treatment is carried out using a device for washing with a free-falling curtain-like liquid film shown in FIG. 2, and further, for 5 seconds using a spray tube having a structure having spray tips spread in a fan shape at intervals of 80 mm. This was done by washing with water.

(A) Pretreatment Pretreatment was performed by any of the following pretreatment methods A to D. Table 1 shows which processing method was used. Moreover, since the comparative example 3 did not perform pre-processing, it described with "-" in Table 1. Further, describing the arithmetic mean roughness R _a after the pretreatment in Table 1.

(Method A)
The obtained aluminum plate was brought into rolling contact with 10 pass rolls having a diameter of 200 mm at a wrap angle of 180 degrees, and repeatedly subjected to bending treatment. Thereafter, an alkaline solution (liquid temperature 60 ° C.) containing 27% by mass of NaOH and 6.5% by mass of aluminum ions was sprayed using a spray tube. The dissolution amount of the aluminum plate was 1.5 g / m ² .
Here, the rolling contact of the aluminum plate to the 10 pass rolls is such that the uneven surface of the aluminum plate and the back surface on the opposite side are in contact with the roll alternately so that the wrap angle is 180 °. Arranged. Thereby, with the rolling of the pass roll, the aluminum plate was repeatedly bent five times.

(Method B)
Arrange the obtained aluminum plate on 10 pass rolls with a diameter of 200 mm so that the rugged surface of the aluminum plate and the back surface on the opposite side are in contact with the roll alternately so that the wrap angle is 180 °. did. Thereafter, the pass roll was rolled, the aluminum plate was conveyed to a dip tank supplied with water, and the aluminum plate surface was rubbed with a roll rotating in the dip tank so that the roll peripheral speed was AL conveyance speed + 5%. . The roll used was a roll made of nonwoven fabric having a diameter of 200 mm, and the wrap angle between the roll and the aluminum plate surface was 5 degrees. In addition, the water in the dip tank was supplied to a lap portion between the roll and the aluminum plate surface, and was allowed to keep fresh by overflowing from the dip tank.

(Method C)
An alkaline solution (liquid temperature 60 ° C.) containing 27% by mass of NaOH and 6.5% by mass of aluminum ions was sprayed onto the obtained aluminum plate using a spray tube. The dissolution amount of the aluminum plate was 1.5 g / m ² .

(Method D)
A suspension obtained by suspending pumiston having a specific gravity of 1.13 (average particle diameter of 30 μm) in water was used as a polishing slurry liquid, and the surface was polished at a brush rotation speed of 250 rpm using one rotating brush. As the roller-shaped brush, use is made of 6/10 nylon bristles with a bristles length of 50 mm and bristles diameter of 0.295 mm, which are planted so as to be dense by making holes on the surface of a 300 mm diameter stainless steel roller. It was.

(B) Etching Treatment in Alkaline Aqueous Solution For Comparative Example 2, an etching treatment was performed by spraying an aqueous solution of caustic soda concentration of 370 g / L, aluminum ion concentration of 100 g / L, and temperature of 60 ° C. from a spray tube on an aluminum plate. . The etching amount of the surface subjected to the electrolytic surface roughening treatment after the aluminum plate was 5 g / m ² .

(C) Desmutting treatment In Comparative Example 2, the desmutting treatment was performed by spraying a nitric acid aqueous solution having a temperature of 35 ° C. for 5 seconds from the spray tube after the etching treatment of (b). As the nitric acid aqueous solution, the waste liquid (nitric acid concentration 10 g / L, aluminum ion concentration 4.5 g / L) of the electrolytic surface-roughening treatment process using alternating current in the nitric acid aqueous solution described later was used.
Then, without carrying out liquid removal with a nip roller, it conveyed in the state which nitric acid aqueous solution adhered to the aluminum plate. The conveyance time was 25 seconds.

(D) Electrolytic surface roughening treatment using alternating current in aqueous nitric acid solution Immediately before performing the electrolytic surface roughening treatment, an electrolytic solution having the same composition and temperature as the electrolytic solution used for nitric acid alternating current electrolysis described later is applied to the aluminum plate. Sprayed.
Then, electrolytic surface roughening was continuously performed using an AC voltage of 60 Hz using an electrolytic solution (liquid temperature 35 ° C.) in which aluminum nitrate was dissolved in a 10 g / L nitric acid aqueous solution to have an aluminum ion concentration of 4.5 g / L. Processed. The AC power supply waveform is the waveform shown in FIG. 3, and the time Tp until the current value reaches the peak from zero was 1.2 msec, and the duty ratio (ta / T) was 0.5. A carbon electrode was used as the counter electrode. Ferrite was used for the auxiliary anode. Two electrolytic cells shown in FIG. 4 were used.
In the electrolytic surface roughening treatment, the current density during the anode reaction of the aluminum plate at the peak of alternating current was 60 A / dm ² . The ratio of the total amount of electricity during the anode reaction of the aluminum plate to the total amount of electricity during the cathode reaction was 0.95. The amount of electricity was 195 C / dm ^{2 as} the total amount of electricity at the time of anode of the aluminum plate. 5% of the current flowing from the power source was shunted to the auxiliary anode.
The relative speed of the aluminum plate and the electrolytic solution was 1.5 m / sec on average in the electrolytic cell.

(E) Etching treatment in alkaline aqueous solution An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 370 g / L, an aluminum ion concentration of 100 g / L, and a temperature of 64 ° C. for 7 seconds to carry out an etching treatment. The etching amount of the surface subjected to the electrolytic surface roughening treatment of the aluminum plate was 3 g / m ² .

(F) Desmut treatment An aqueous solution (solution temperature 35 ° C.) in which aluminum nitrate was dissolved in 300 g / L nitric acid aqueous solution to make the aluminum ion concentration 5 g / L was sprayed from a spray tube for 10 seconds to perform desmut treatment.

(G) Electrolytic roughening treatment using alternating current in aqueous hydrochloric acid solution Using an electrolytic solution (liquid temperature 35 ° C.) in which aluminum chloride is dissolved in 5 g / L hydrochloric acid aqueous solution to make aluminum ion concentration 5 g / L, 60 Hz An electrolytic surface roughening treatment was continuously performed using an AC voltage of. The AC power supply waveform is the waveform shown in FIG. 3, and the time Tp until the current value reaches the peak from zero was 0.8 msec, and the duty ratio (ta / T) was 0.5. A carbon electrode was used as the counter electrode. Ferrite was used for the auxiliary anode. One electrolytic cell shown in FIG. 4 was used.
In the electrolytic surface roughening treatment, the current density during the anode reaction of the aluminum plate at the peak of alternating current was 50 A / dm ² . The ratio of the total amount of electricity during the anode reaction of the aluminum plate to the total amount of electricity during the cathode reaction was 0.95. The amount of electricity was 63 C / dm ^{2 as} the total amount of electricity at the time of anode of the aluminum plate. 5% of the current flowing from the power source was shunted to the auxiliary anode. The relative speed of the aluminum plate and the electrolytic solution was 1.5 m / sec on average in the electrolytic cell.
Thereafter, the liquid was drained with a nip roller, washed with water, and drained with a nip roller.

(H) Etching treatment in alkaline aqueous solution An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 50 g / L, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. for 2 seconds from a spray tube to carry out the etching treatment. The etching amount of the surface subjected to the electrolytic surface roughening treatment of the aluminum plate was 0.1 g / m ² .

(I) Desmutting treatment As an aqueous solution, a desmutting treatment was performed at a liquid temperature of 60 ° C. for 5 seconds using a waste liquid from an anodizing process described later (sulfuric acid concentration 170 g / L, aluminum ion concentration 5 g / L).
Thereafter, the liquid was drained by a nip roller, but the water washing treatment was not performed until anodizing.

(J) Anodizing treatment As an electrolytic solution, an electrolytic solution (temperature 33 ° C.) in which aluminum sulfate was dissolved in a 170 g / L sulfuric acid aqueous solution to have an aluminum ion concentration of 5 g / L was used. The anodizing treatment was performed so that the average current density during the anodic reaction of the aluminum plate was 15 A / dm ² , and the final DC anodized film amount was 2.4 g / m ² .

(K) Hydrophilization treatment The aluminum plate was immersed in a 2.5% by weight aqueous solution of sodium silicate (liquid temperature 20 ° C.) for 10 seconds. The amount of Si on the surface of the aluminum plate measured with a fluorescent X-ray analyzer was 3.5 mg / m ² .
Thereafter, the liquid was drained with a nip roller, further washed with water, and drained with a nip roller.
Then, 90 degreeC wind was blown for 10 seconds and it dried, and the support body for lithographic printing plates was obtained.

3. Evaluation of lithographic printing plate support Residual amount of surface AL pieces (pieces / mm ² ) after pretreatment and just before electrolytic roughening, AL on pass roll surface after continuous production of each lithographic printing plate support 10000 m The presence or absence of small pieces and the periodic failure rate (%) were evaluated by the following methods. Also, arithmetic mean roughness after pretreatment of the surface R _a was also measured. These results are shown in Table 1.

(1) AL small piece remaining amount (pieces / mm ² )
After pre-treatment and friction with a plurality of pass rolls, the aluminum plate immediately before the electrolytic surface-roughening treatment was cut out, and the surface was observed with 30 fields of view with an electron microscope (magnification 300 times). Piece / mm ² ) was calculated. The residual amount of AL pieces before pretreatment (pieces / mm ² ) was 70 (pieces / mm ² ) as can be seen from the results of Comparative Example 3.

(2) Presence or absence of AL pieces on the surface of the pass roll The presence or absence of AL pieces on the surface of the pass roll after 10,000 m continuous production of each lithographic printing plate support was confirmed using a loupe and a CCD microscope.

(3) Periodic failure rate (%)
Periodic failure occurrence rate after 10000m continuous production of each lithographic printing plate support is extracted with a laser scanning online automatic surface inspection machine (FL-9000, manufactured by Fuji Photo Film Co., Ltd.). A label was affixed to the portion, and the ratio of the portion to 10,000 m was measured. Here, the periodical failure occurrence rate (%) indicates the ratio of the aluminum plate that cannot be used to 10,000 meters. In addition, since the failure portion is determined in units of 1 m, for example, when there is a failure portion at a rate of 1 in 100 m, there are 100 failure portions in 10000 m, and 100 m for 10000 m. It cannot be used for a minute. Therefore, the periodic failure occurrence rate (%) in this case is 1%.

As is apparent from Table 1, in Example 1, the AL pieces were completely removed, and the adhesion to the surface of the pass roll was eliminated, and as a result, no periodic failure occurred. This is because the aluminum plate is repeatedly rolled onto the pass roll at a wrap angle of 180 °, and a gap is created between the AL piece that is in close contact with the aluminum surface and the aluminum surface. It is considered that the micro-protrusions were removed by the chemical etching process using an alkaline solution because the flaps that were likely to be peeled off and separated by the surface were also lifted. In Reference Example 2, the AL pieces were completely removed, and the adhesion to the surface of the pass roll was eliminated, resulting in no periodic failure.
In contrast, Comparative Example 1 was treated with an alkaline solution under the same conditions as in Example 1, but was not subjected to repeated bending in advance, so the remaining amount of AL pieces was 10 / mm ² , and the surface of the pass roll was The periodic failure rate was also 2%.
In Comparative Example 2, since the surface was polished with a brush roll using a pumiston liquid, the AL pieces were completely removed, but the surface shape could not maintain the original transferred uneven shape. . The reason why the failure rate did not become zero is presumed that the abrasive in the pumiston liquid caused scratches.
In Comparative Example 3, since no pretreatment was performed, a large amount of AL pieces were generated due to slight friction with the roll until the electrolytic surface-roughening treatment, and this AL piece adhered to the surface of the pass roll. This is thought to have led to an increase in the periodic failure rate.

FIG. 1 is a schematic diagram for explaining an uneven shape on the surface of an aluminum plate. FIG. 2 is a schematic cross-sectional view of an apparatus for washing with a free-falling curtain-like liquid film used for washing with water in the method for producing a lithographic printing plate support of the present invention. FIG. 3 is a graph showing an example of an alternating waveform current waveform diagram used for the electrolytic surface roughening treatment in the method for producing a lithographic printing plate support of the present invention. FIG. 4 is a side view showing an example of a radial cell in electrolytic surface-roughening treatment using alternating current in the method for producing a lithographic printing plate support of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum plate 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 anode 19a, 19b Thyristor 20 AC power supply 30 Aluminum plate 31 Roll 32 Oval recessed part 33 Flap 34 AL small piece 40 Main electrolytic cell 50 Auxiliary anode cell 200 Water washing device with free-fall curtain liquid film 202 Water 204 Water storage tank 206 Water supply cylinder 208 Rectifier

Claims (1)

An aluminum plate having a surface with an arithmetic average roughness _Ra of 0.5 to 1.0 μm having a micro-protrusion and a concavo-convex shape transferred using a roughened roll, at least one of the micro-protrusion parts or to remove the entire pretreatment to reduce the arithmetical mean roughness R _a, and subjected to electrochemical graining treatment in this order to prepare a lithographic printing plate support, a lithographic printing plate support A manufacturing method comprising:
The arithmetic mean roughness R _a after applying the pre-treatment is 0.3～0.9Myuemu,
The method for producing a support for a lithographic printing plate, wherein the pretreatment comprises a repeated bending treatment for the aluminum plate 5 times or more and a subsequent chemical etching treatment using an alkaline solution.