JP2006021426A - Manufacturing method of support for lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a support for a lithographic printing plate, by which a lithographic printing form original plate excellent both in resistance to dirt and in plate wearability can be obtained by employing alternating current electrolysis in aqueous solution containing hydrochloric acid. <P>SOLUTION: In this manufacturing method of the support for the lithographic printing plate, the support for the lithographic printing plate is obtained by applying at least an electrochemical roughening treatment using the triangular wave alternating current in the aqueous solution containing hydrochloric acid and an electrochemical roughening treatment using the alternating current in the aqueous solution containing hydrochloric acid in this order to an aluminum plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a lithographic printing plate support. More specifically, the present invention relates to a method for producing a lithographic printing plate support used for a lithographic printing plate precursor that is excellent in both stain resistance and printing durability.

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 treatment, electrochemical roughening treatment (hereinafter also referred to as “electrolytic roughening treatment”), and chemical roughening treatment (chemical etching). A method combining these is known.
Among them, in electrochemical roughening treatment, a method using alternating current in an aqueous solution containing hydrochloric acid is widely used in that fine irregularities can be generated on the surface of an aluminum plate.

For example, Patent Document 1 discloses a time TP until the current reaches a peak from 0 in a method of electrochemically roughening the surface of a continuously traveling aluminum plate using an alternating current in an acidic aqueous solution. Describes a roughening treatment method for an aluminum support for a lithographic printing plate, characterized by using a triangular wave of 1 to 50% of the time TA in which the aluminum plate is an anode in a waveform of one cycle, and as an acidic aqueous solution And aqueous hydrochloric acid.
Further, in Patent Document 2, the surface of an aluminum plate is sequentially (a) mechanically roughened, and (b) chemically etched in an acid or alkali aqueous solution or electrochemically in a neutral salt aqueous solution. (C) Electrochemical roughening treatment in an aqueous solution mainly composed of hydrochloric acid, (d) Chemical etching treatment in an acid or alkali aqueous solution or electrochemical reaction in a neutral salt aqueous solution A method for producing a support for a lithographic printing plate, characterized in that it is etched and (e) electrochemically roughened in an aqueous solution mainly composed of nitric acid.

Further, in Patent Document 3, electrochemical graining is performed in the graining process by alternating current in an acidic electrolyte containing sulfate ions and chloride ions, and the chloride ions are in the form of aluminum chloride. A method of graining aluminum or an aluminum alloy for a printing plate support, wherein mechanical, dry or wet graining is performed in a preceding or subsequent graining step, and / or Electrochemical coarsening by alternating current in an electrolyte containing aluminum ions introduced as hydrochloric acid and aluminum chloride, aluminum ions introduced as nitric acid and aluminum nitrate, or chloride ions introduced as sulfuric acid and aluminum chloride. A method is described, characterized by:
Patent Document 4 discloses a surface roughening method for carrying out two electrochemical surface roughening steps and a chemical cleaning step for aluminum or an aluminum alloy as a support material for a printing plate, the first electrochemical method. The surface roughening step is carried out in an electrolyte containing hydrochloric acid, nitric acid or sulfuric acid and chloride ions or nitrate ions, and the subsequent electrochemical surface roughening step is carried out with the concentration of the additive being the first rough surface. A method is described which is characterized in that it is carried out in an electrolyte solution which is the same as or different from the concentration of the additive in the forming step, and finally chemical cleaning of the surface of the support material is carried out.

In addition, Patent Document 5 discloses a support material for a printing plate manufactured from pre-engraved aluminum or a pre-engraved aluminum alloy in which a hemispherical indent having a diameter of 2 to 50 μm is engraved on one surface. A method of roughening, wherein an electrochemical roughening step proceeds in an electrolyte selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid and chlorides of aluminum salts or nitrate ions by alternating current, _A method is described in which the electrochemical roughening step is carried out in such a way that the roughening is uniformly carried out with a surface roughness R _A of 1.0 to 1.5 μm and covering the region.

JP 10-44636 A JP-A-6-171260 Japanese Patent Laid-Open No. 5-4466 JP-A-5-278361 JP 2002-38300 A

However, it has not been possible to obtain a lithographic printing plate support excellent in both printing durability and stain resistance by the conventional method using AC electrolysis in an aqueous solution containing hydrochloric acid as described above.
Therefore, the present invention provides a method for producing a lithographic printing plate support capable of obtaining a lithographic printing plate precursor excellent in both stain resistance and printing durability using alternating current electrolysis in an aqueous solution containing hydrochloric acid. The purpose is to provide.

  As a result of diligent research to achieve the above object, the present inventor has found that an aluminum plate is subjected to an electrochemical surface roughening treatment using triangular wave alternating current in an aqueous solution containing at least hydrochloric acid, and an aqueous solution containing hydrochloric acid. In this order, the lithographic printing plate precursor using the lithographic printing plate support was excellent in both stain resistance and printing durability. As a result, the present invention has been completed.

  That is, the present invention provides the following (1) to (3).

  (1) An electrochemical surface roughening treatment using an alternating current in an aqueous solution containing hydrochloric acid, and an electrochemical surface roughening treatment using a triangular wave alternating current in an aqueous solution containing hydrochloric acid. A method for producing a lithographic printing plate support, wherein the treatment is performed in this order to obtain a lithographic printing plate support.

  (2) On the side where the aluminum plate of the triangular wave becomes the anode, the time until the current reaches a peak from zero is ¼ or less of the time when the aluminum plate becomes the anode. A method for producing a lithographic printing plate support.

  (3) The method for producing a lithographic printing plate support according to (1) or (2), wherein the aluminum plate has an uneven pattern on the surface.

  As will be described below, according to the present invention, a support for a lithographic printing plate used for a lithographic printing plate precursor that is excellent in both stain resistance and printing durability when used as a lithographic printing plate can be obtained.

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 mainly composed of 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 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.

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 aluminum plates such as A1050, JIS A1100, JIS A1070, JIS A3004 containing Mn, and internationally registered alloy 3103A can be appropriately used. 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 UBC (Used Beverage Can) ingot which melt | dissolved the used aluminum beverage can can also be used.
In this aluminum plate, the Cu content is preferably 0.00% by mass or more, more preferably 0.01% by mass or more, and more preferably 0.02% by mass or more, and 0.15% by mass. % Or less, preferably 0.11% by mass or less, more preferably 0.03% by mass or less. Particularly preferred are Si: 0.07 to 0.09 mass%, Fe: 0.20 to 0.29 mass%, Cu: 0.03 mass% or less, Mn: 0.01 mass% or less, Mg: 0 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, and Al: 99.5% by mass or more.

  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 applicant of the present application 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 the soaking process, 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.

  The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps 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 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.

  The aluminum plate used in the present invention is preferably subjected to H18 tempering as defined in JIS.

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 crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.

  The alloy component distribution of the aluminum plate, when chemical surface roughening treatment or electrochemical surface roughening treatment is performed, poor surface quality occurs due to non-uniform distribution of the alloy component on the surface of the aluminum plate. Therefore, it is preferable that the surface is not very uneven. With regard to these, the techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-48058, 5-301478, and 7-132689.

  In the intermetallic compound of the aluminum plate, the size and density of the intermetallic compound may affect the chemical roughening treatment or the electrochemical roughening treatment. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 7-138687 and 4-254545.

  In the present invention, an aluminum plate as shown above can be used by forming irregularities by press rolling, transfer or the like in the final rolling step or the like.

Above all, along with cold rolling to adjust the final plate thickness or finish cold rolling to finish the surface shape after final plate thickness adjustment, the uneven surface is transferred to the aluminum plate surface by pressing the uneven surface to the aluminum plate. A method of forming an uneven pattern is preferred. Specifically, the method described in JP-A-6-262203 can be suitably used.
By using an aluminum plate having a concavo-convex pattern on the surface, it is possible to obtain a concavo-convex pattern having a uniform average pitch and depth than the concavo-convex pattern formed by the brush and the abrasive, thereby improving the stain resistance. In addition, the amount of dampening water on the printing press can be easily adjusted while reducing energy consumed in the subsequent alkali etching treatment and surface roughening treatment. For example, in the first etching process described later, the etching amount can be reduced to about 3 g / m ² or less. In addition, when an aluminum plate having a concavo-convex pattern is used, the surface area of the obtained lithographic printing plate support is increased, so that the printing durability is more excellent.

The transfer is particularly preferably performed in the final cold rolling step of a normal aluminum plate. Rolling for transfer is preferably performed in 1 to 3 passes, and each rolling reduction is preferably 3 to 8%.
Moreover, it is more preferable that the unevenness | corrugation provided by transcription | transfer is provided on both surfaces of an aluminum plate. Thereby, since the elongation rate of the aluminum plate of a surface and a back surface can be adjusted to the same grade, an aluminum plate with sufficient flatness can be obtained.

Examples of a method for obtaining a rolling roll having irregularities on the surface used for irregularity transfer include a blast method, an electrolytic method, a laser method, an electric discharge machining method, and a combination of these. Among these, a method in which the blast method and the electrolytic method are combined is preferable. Among the blast methods, the air blast method is preferable.
The air pressure in the air blast method is preferably 1 to 10 kgf / cm ² (9.81 × 10 ^{4 to} 9.81 × 10 ⁵ Pa), and ² to ⁵ kgf / cm ² (1.96 × 10 ⁵ to More preferably 4.90 × 10 ⁵ Pa).
The grid used in the air blast method is not particularly limited as long as it is alumina particles having a predetermined particle size. If alumina particles having hard and sharp corners are used for the grid, it is easy to form deep and uniform irregularities on the surface of the transfer roll.
The average particle diameter of the alumina particles is 50 to 150 μm, preferably 60 to 130 μm, and more preferably 70 to 90 μm. If it is within the above range, a surface roughness having a sufficient size as a transfer roll can be obtained, so that the surface roughness of an aluminum plate provided with irregularities using this transfer roll is sufficiently increased. Also, the number of pits can be increased sufficiently.

In the air blast method, the injection is preferably performed 2 to 5 times, and more preferably 2 times. When the injection is performed twice, the uneven portions of unevenness formed by the first injection can be scraped off by the second injection, so that the surface of the aluminum plate provided with the unevenness using the obtained rolling roll, Locally deep recesses are less likely to be formed. As a result, the developability (sensitivity) of the lithographic printing plate is excellent.
The injection angle in the air blast method is preferably 60 to 120 °, more preferably 80 to 100 ° with respect to the injection surface (roll surface).

After performing the air blasting method, it is preferable to perform polishing until the average surface roughness ( _Ra ) is reduced by 10 to 40% from the value after air blasting before performing the plating treatment described later. For polishing, it is preferable to use sandpaper, a grindstone, or a buff. By polishing, the height of the projections on the surface of the transfer roll can be made uniform, and as a result, locally deep portions are not formed on the surface of the aluminum plate provided with irregularities using this transfer roll. As a result, the developability (sensitivity) of the planographic printing plate is particularly excellent.

The average surface roughness ( _Ra ) of the surface of the transfer roll is preferably 0.4 to 1.0 [mu] m, and more preferably 0.6 to 0.9 [mu] m.
Number of peaks of the surface of the transfer roll is preferably from 1000 to 40000 pieces / mm ^2, and more preferably 2,000 to 10,000 pieces / mm ^2. If the number of peaks is too small, the water retention of the lithographic printing plate support and the adhesion to the image recording layer are poor. If the water retention is inferior, the halftone dot portion tends to become dirty when a planographic printing plate is used.

The material of the transfer roll is not particularly limited, and for example, a known material for a rolling roll can be used.
In the present invention, it is preferable to use a steel roll. Among these, a roll made by casting is preferable. An example of a composition of a preferable roll material is C: 0.07 to 6% by mass, Si: 0.2 to 1% by mass, Mn: 0.15 to 1% by mass, P: 0.03% by mass or less, S: 0.03% by mass or less, Cr: 2.5 to 12% by mass, Mo: 0.05 to 1.1% by mass, Cu: 0.5% by mass or less, V: 0.5% by mass or less, balance: iron And inevitable impurities.
Further, tool steel (SKD), high-speed steel (SKH), high carbon chromium bearing steel (SUJ), and forged steel containing carbon, chromium, molybdenum, and vanadium as alloy elements, which are generally used as rolling rolls, can be mentioned. It is done. In order to obtain a long roll life, a high chromium alloy cast iron containing about 10 to 20% by mass of chromium can also be used.
Among these, it is preferable to use a roll manufactured by a casting method. In this case, the hardness after quenching and tempering is preferably 80 to 100 in terms of Hs. The tempering is preferably performed at a low temperature.
The diameter of the roll is preferably 200 to 1000 mm. Moreover, it is preferable that the surface length of a roll is 1000-4000 mm.

The transfer roll formed with irregularities by the air blast method or the like is preferably subjected to hardening treatment such as quenching and hard chrome plating after washing. This improves wear resistance and prolongs life.
As the hardening treatment, hard chrome plating is particularly preferable. Hard chromium plating can be performed by electroplating using a conventionally known CrO ₃ —SO ₄ bath, CrO ₃ —SO ₄ —fluoride bath, or the like as an industrial chromium plating method.
The thickness of the hard chrome plating film is preferably 3 to 15 μm, and more preferably 5 to 10 μm. If it is in the above range, the plating peeling is difficult to peel off from the boundary between the roll surface substrate and the plating film, and the effect of improving the wear resistance is sufficient. The thickness of the hard chrome plating film can be adjusted by adjusting the plating treatment time.
Prior to the hard chrome plating, it is preferable to perform electrolytic treatment at a quantity of electricity of 5,000 to 50,000 C / dm ² using a direct current using a roll as an anode in a plating solution used for hard chrome plating. . Thereby, the unevenness | corrugation of the surface of a roll can be equalize | homogenized.

For an aluminum plate, the average surface roughness _Ra is measured by measuring the two-dimensional roughness with a stylus type roughness meter (for example, sufcom 575, manufactured by Tokyo Seimitsu Co., Ltd.) and measuring the average roughness specified in ISO4287. _Ra is measured 5 times, and the average value is defined as the average roughness.
The conditions for the two-dimensional roughness measurement are shown below.
<Measurement conditions>
Cut-off value 0.8mm, tilt correction FLAT-ML, measurement length 3mm, vertical magnification 10,000 times, scanning speed 0.3mm / sec, stylus tip diameter 2μm
R _max and R _sm can be measured in accordance with ISO 4287.

The aluminum plate used in the present invention is a continuous belt-like sheet material or plate material. That is, it may be an aluminum web, or a sheet-like sheet cut to a size corresponding to a planographic printing plate precursor shipped as a product.
Since scratches on the surface of the aluminum plate may become defects when processed into a lithographic printing plate support, it is possible to generate scratches at the stage prior to the surface treatment process for making a lithographic printing plate support It is necessary to suppress as much as possible. For that purpose, it is preferable that the package has a stable form and is hardly damaged during transportation.
In the case of an aluminum web, for example, the packaging of aluminum is, for example, laying a hardboard and felt on an iron pallet, applying cardboard donut plates to both ends of the product, wrapping the whole with a polytube, and inserting a wooden donut into the inner diameter of the coil Then, a felt is applied to the outer periphery of the coil, the band iron is used to squeeze it, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and needle felt and hard board can be used as the cushioning material. There are various other forms, but the present invention is not limited to this method as long as it is stable and can be transported without being damaged.

  The thickness of the aluminum plate used in the present invention is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and more preferably 0.2 to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, the user's desires, and the like.

<Surface treatment>
The method for producing a lithographic printing plate support of the present invention comprises an electrochemical surface roughening treatment (hereinafter referred to as “No. 1”) using the sinusoidal alternating current in an aqueous solution containing at least hydrochloric acid and sulfuric acid. 1 "electrochemical roughening treatment") and electrochemical roughening treatment using alternating current in an aqueous solution containing hydrochloric acid (hereinafter also referred to as "second electrochemical roughening treatment"). .) In this order to obtain a lithographic printing plate support.
In the method for producing a lithographic printing plate support of the present invention, various steps other than those described above may be included.

Specifically, for example, an etching treatment in an alkaline aqueous solution (hereinafter also referred to as “first etching treatment”), a desmutting treatment in an acidic aqueous solution (hereinafter also referred to as “first desmutting treatment”), and hydrochloric acid are contained. Electrochemical roughening treatment using triangular wave alternating current in an aqueous solution, etching treatment in an alkaline aqueous solution (hereinafter also referred to as “second etching treatment”), desmutting treatment in an acidic aqueous solution (hereinafter referred to as “second”). Also called “desmut treatment”), electrochemical roughening treatment using alternating current in an aqueous solution containing hydrochloric acid, etching treatment in an alkaline aqueous solution (hereinafter also referred to as “third etching treatment”), acidic aqueous solution Among them, a method in which the desmutting treatment (hereinafter also referred to as “third desmutting treatment”) and the anodizing treatment are performed in this order is preferable.
Further, after the anodizing treatment, a sealing treatment, a hydrophilization treatment, or a sealing treatment and a subsequent hydrophilization treatment are also preferable.

Further, a mechanical surface roughening process can be performed before the first etching process. Thereby, the amount of electricity used for the first electrochemical surface roughening treatment can be reduced.
Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication No. 50. The brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. -40047 can be used.
Moreover, the transfer method (transfer roll method) which press-contacts an uneven surface to an aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in JP-A-6-24168 and JP-A-6-24168 characterized in that the surface is elastic is also applicable.
Among these, the transfer roll method is preferable because it can easily cope with the speedup of the manufacturing process of the support for a lithographic printing plate. As described above, the transfer roll method preferably performs transfer in cold rolling for adjusting to the final plate thickness or finishing cold rolling for finishing the surface shape after final plate thickness adjustment.

  Hereinafter, each step of the surface treatment will be described in detail.

<First etching process>
An alkali etching process is a process which melt | dissolves a surface layer by making the aluminum plate mentioned above contact an alkaline solution.

The first etching process performed before the first electrochemical surface roughening process is to form a uniform recess by the first electrochemical surface roughening process and to roll the surface of the aluminum plate (rolled aluminum). It is performed for the purpose of removing oil, dirt, natural oxide film and the like.
In the first etching treatment, the etching amount of the surface to be subjected to the electrochemical roughening treatment later is preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more. but preferably not more 10 g / m ² or less, more preferably 5 g / m ² or less. When the etching amount is 0.5 g / m ² or more, uniform pits can be generated in the first electrochemical surface roughening treatment. When the etching amount is 10 g / m ² or less, the amount of the alkaline aqueous solution used is reduced, which is economically advantageous.

The etching amount of the back surface of the surface subjected to the electrochemical roughening treatment is preferably 5% or more of the etching amount of the surface subjected to the electrochemical roughening treatment, and preferably 10% or more. Is more preferably 50% by mass or less, and more preferably 30% by mass or less. It is excellent in the balance with the removal effect of the rolling oil of the back surface of an aluminum plate, and economical efficiency as it is the said range.
The same applies to a second etching process and a third etching process described later.

  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 the alkali metal salt include alkali metal silicates such as sodium metasilicate, 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, primary sodium phosphate, primary 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 etching treatment, the concentration of the alkaline solution is preferably 1% by mass or more, more preferably 20% by mass or more, and preferably 35% by mass or less, and 30% by mass or less. It is more preferable that
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 0.5% by mass or more, more preferably 4% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass 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 etching treatment, the temperature of the alkaline solution is preferably 25 ° C. or higher, more preferably 40 ° C. or higher, preferably 95 ° C. or lower, and 80 ° C. or lower. More preferred.
In the first 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. .

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 hydrometer, it is preferable to use a differential pressure type.

  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.

FIG. 1 is a schematic cross-sectional view of an apparatus for washing with a free-fall curtain-like liquid film. As shown in FIG. 1, an apparatus 100 for performing water washing treatment with a free-fall curtain-like liquid film includes a water storage tank 104 that stores water 102, a water supply pipe 106 that supplies water to the water storage tank 104, and a water storage tank. And a rectifying unit 108 for supplying a free-falling curtain-like liquid film from 104 to the aluminum plate 1.
In the apparatus 100, water 102 is supplied to the water supply tank 104 from the water supply pipe 106, and when the water 102 overflows from the water supply tank 104, the water is rectified by the rectifying unit 108, and a free-falling curtain-like liquid film is applied to the aluminum plate 1. Supplied. When the apparatus 100 is used, the liquid amount is preferably 10 to 100 L / min. Moreover, it is preferable that the distance L in which the water 102 between the apparatus 100 and the aluminum 1 exists as a free fall curtain-like liquid film is 20-50 mm. Moreover, it is preferable that the angle (alpha) of an aluminum plate is 30-80 degrees with respect to a horizontal direction.

If an apparatus for washing with a free-fall curtain-like liquid film as shown in FIG. 1 is used, the aluminum plate can be uniformly washed with water, so that the uniformity of the treatment performed before the washing process is 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>
After the first etching process, it is preferable to perform pickling (first desmut process) 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, hydrochloric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. Of these, nitric acid and sulfuric acid are preferable. Specifically, for example, a waste solution of an aqueous sulfuric acid solution used in an anodic oxidation process described later can be suitably used.

  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 0.5 to 30% by mass of acid and 0.5 to 10% by mass of aluminum ions.

  The temperature of the acidic solution is preferably 25 ° C. or higher, and preferably 95 ° C. or lower.

  In the first desmutting treatment, the treatment time is preferably 1 second or more, more preferably 2 seconds or more, and preferably 30 seconds or less, more preferably 10 seconds or less. .

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.

<First electrochemical surface roughening treatment>
The first electrochemical surface roughening treatment is an electrochemical surface roughening treatment using triangular wave alternating current in an aqueous solution containing hydrochloric acid. By this first electrochemical surface roughening treatment, the plateau portion (flat portion) is small, preferably has a uniform recess having an average diameter of 2 to 20 μm, and preferably has an average surface roughness of 0.3 to 0.8 μm. A surface shape is obtained. As described above, in the present invention, since the plateau portion is small on the surface after the first electrochemical roughening treatment, the plate life is excellent when a planographic printing plate is used, and the pits are uniform. Therefore, the stain resistance when the planographic printing plate is obtained is excellent.
On the other hand, when the trapezoidal wave alternating current is used, the pits become shallow or overlap, and become non-uniform. In addition, the plateau part increases.

  The hydrochloric acid concentration in the aqueous solution used as the electrolytic solution is preferably 3 to 30 g / L, more preferably 4 to 20 g / L, and still more preferably 5 to 15 g / L. Within the above range, the uniformity of the pits becomes high.

  To the aqueous solution, a hydrochloric acid compound or a nitric acid compound having a nitrate ion such as aluminum nitrate, sodium nitrate or ammonium nitrate, or a hydrochloric acid ion such as aluminum chloride, sodium chloride or ammonium chloride can be added and used. Moreover, the compound which forms a complex with copper can also be added in the ratio of 1-200 g / L. In the aqueous solution, a metal contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium, or silica may be dissolved. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L.

  The aluminum ion concentration in the aqueous solution is preferably 3 to 30 g / L, more preferably 3 to 20 g / L, and still more preferably 4 to 15 g / L. Within the above range, the uniformity of the pits becomes high. Moreover, the replenishment amount of the aqueous solution does not increase too much.

The concentration control of each component of the electrolytic solution is preferably performed using a combination of a multi-component concentration measurement method such as a concentration measurement method, feedforward control and feedback control. Thereby, accurate concentration management of the electrolytic solution becomes possible.
The multi-component concentration measurement method is, for example, a method of measuring the concentration using the propagation speed of ultrasonic waves in the liquid and the electric conductivity (conductivity) of the liquid, neutralization titration method, capillary electrophoresis analysis method, isotacophoresis (Isochophoresis, capillary tube isotachophoresis) Analytical method and ion chromatographic method are mentioned.
The ion chromatograph method is classified into an absorbance detection ion chromatograph, a non-suppressor type electric conductivity detection ion chromatograph, a suppressor type ion chromatograph, and the like depending on the type of detector. Among these, a suppressor type ion chromatograph is preferable from the viewpoint of ensuring measurement stability.

Electrical amount in the first electrochemical graining treatment, an aluminum plate is amount of electricity when the anode sum is preferably from 150~800C / dm ^2, more preferably from 200~700C / dm ² 200 to 500 C / dm ² is more preferable. When it is 150 C / dm ² or more, the surface roughness becomes sufficient, and the printing durability and the ease of adjusting the amount of water during printing become more excellent. When it is 800 C / dm ² or less, the stain resistance is more excellent.
Moreover, when using the aluminum plate which formed the uneven | corrugated pattern by transcription | transfer, it is especially preferable that it is 200-400 C / dm < ² >.

The current density in the first electrochemical surface roughening treatment is preferably 30 to 300 A / dm ² at the peak of the current value, more preferably 50 to 200 A / dm ² , and 75 to 125 A / dm 2. ² is more preferable. When it is 30 A / dm ² or more, the productivity is further improved. When it is 300 A / dm ² or less, the voltage is not high and the power source capacity does not become too large, so that the power source cost can be reduced.

  The first electrochemical surface roughening treatment can be performed according to, 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.

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-52-133638, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 And those described in JP-A No. 54-146234 and the like can also be used.

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

  The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 25 ° C. or higher, still more preferably 30 ° C. or higher, and preferably 60 ° C. or lower, and 50 ° C. or lower. Is more preferable, and it is still more preferable that it is 40 degrees C or less. When the temperature is 20 ° C. or higher, the refrigerator operating cost for cooling does not increase, and the amount of groundwater used for cooling can be suppressed. It is easy to ensure the corrosion resistance of equipment as it is 60 ° C. or lower.

The AC power supply wave used for the first electrochemical surface roughening treatment is a triangular wave. A triangular wave means what was shown in FIG.
In the triangular wave, on the side where the aluminum plate becomes the anode, the time until the current reaches the peak from zero (current rise time, TP) is ¼ or less of the time (TA) when the aluminum plate becomes the anode. preferable. The current rise time (TP) is preferably 0 to 2 msec, and more preferably 0.5 to 1.5 msec. When it is 2 msec or less, the uniformity of pits becomes more excellent.

  The AC frequency is preferably 10 to 200 Hz, more preferably 20 to 150 Hz, and still more preferably 30 to 120 Hz. When the frequency is 10 Hz or more, large faceted (pitched square shape) pits are not easily formed, and the stain resistance is more excellent. If it is 200 Hz or less, it is difficult to be influenced by the inductance component of the circuit through which the electrolytic current flows, and it becomes easy to manufacture a large-capacity power supply.

  Moreover, as a power supply device, what used commercial alternating current, an inverter control power supply, etc. can be used, for example. In particular, an inverter control power source using an IGBT (Insulated Gate Bipolar Transistor) element changes the voltage with respect to the width and thickness of the aluminum plate, the concentration of each component in the electrolytic solution, etc. When the current density of the plate) is controlled to be constant, this is preferable in terms of excellent followability.

FIG. 4 is a side view showing an example of a radial type cell used for electrochemical surface roughening using alternating current in 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 tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. The current ratio (ratio of the total amount of electricity when the aluminum plate is the anode and the total amount of electricity when the aluminum plate is the cathode) is preferably 0.9 to 3, and preferably 0.95 to 2. More preferred.

  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.

After the first electrochemical surface roughening treatment 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 distance 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.

For example, the average opening diameter of the recesses generated by the first electrochemical surface roughening treatment is obtained by photographing the surface of the support from directly above at a magnification of 2000 times or 50000 times using an electron microscope. In the photomicrograph, at least 50 pits each generated in a ring-like periphery are extracted, and the diameter is read to obtain the opening diameter, and the average opening diameter is calculated.
In addition, in order to suppress variation in measurement, it is possible to perform equivalent circle diameter measurement using commercially available image analysis software. In this case, the electron micrograph is captured by a scanner, digitized, and binarized by software, and then an equivalent circular diameter is obtained.
As a result of measurement by the present inventor, the result of visual measurement and the result of digital processing showed almost the same value.

<Second etching process>
A second etching process performed between the first electrochemical surface roughening process and the second electrochemical surface roughening process includes dissolving the smut generated by the first electrochemical surface roughening process; and In order to dissolve the edge portion of the pit formed by the first electrochemical surface roughening treatment. As a result, the edge portion of the large pit formed by the first electrochemical surface roughening process is melted and the surface becomes smooth, and the ink is less likely to be caught on the edge portion. Therefore, the lithographic printing plate precursor having excellent stain resistance Can be obtained.
The second etching treatment is basically the same as the first etching treatment, the etching amount is preferably at 0.01 g / m ² or more, more preferably 0.05 g / m ² or more, further preferably at 0.1 g / m ² or more, but preferably not more 10 g / m ² or less, more preferably at 5 g / m ² or less, more preferably at 3 g / m ² or less .

<Second desmut treatment>
After the second etching process, it is preferable to perform pickling (second desmut process) in order to remove dirt (smut) remaining on the surface. The second desmut process can be performed in the same manner as the first desmut process.

<Second electrochemical roughening treatment>
The second electrochemical surface roughening treatment is an electrochemical surface roughening treatment using alternating current in an aqueous solution containing hydrochloric acid. In the present invention, by combining the above-described first electrochemical roughening treatment and the second electrochemical roughening treatment, a complex uneven structure can be formed on the surface of the aluminum plate, As a result, the printing durability can be improved. The second electrochemical surface roughening treatment generates fine pits having an average opening diameter of 0.05 to 0.3 μm on the aluminum surface smoothed by the second etching treatment. Thereby, printing durability can be enhanced.

  The second electrochemical roughening treatment performed after the first electrochemical roughening treatment is the first except that the electrolyte does not necessarily contain sulfuric acid and the AC power supply waveform is not limited. This is basically the same as that described in the electrochemical surface roughening treatment. Hereinafter, differences from the first electrochemical roughening treatment will be mainly described.

The hydrochloric acid concentration in the aqueous solution used as the electrolytic solution is preferably 3 to 30 g / L, more preferably 5 to 20 g / L, and still more preferably 5 to 15 g / L. Within the above range, the uniformity of the pits becomes high.
Further, the aqueous solution may contain sulfuric acid or nitric acid in an amount of 0.05 to 5 g / L.

  The aluminum ion concentration in the aqueous solution is preferably 3 to 30 g / L, more preferably 3 to 20 g / L, and still more preferably 4 to 15 g / L. Within the above range, the uniformity of the pits becomes high. Moreover, the replenishment amount of the aqueous solution does not increase too much.

Quantity of electricity in the second electrochemical graining treatment, an aluminum plate is amount of electricity when the anode sum is preferably from 10~300C / dm ^2, more preferably from 30~150C / dm ² 50 to 100 C / dm ² is more preferable. When it is 10 C / dm ² or more, the printing durability is more excellent. When it is 300 C / dm ² or less, the stain resistance is more excellent.

  The second electrochemical surface roughening treatment can be performed according to, 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.

  The AC power supply wave used for the second 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 trapezoidal wave, a sine wave or a triangular wave is preferable. A trapezoidal wave means what was shown in FIG. In the trapezoidal wave, the time until the current reaches a peak from zero (current rise time, TP) is preferably 0.3 to 2 msec, and more preferably 0.5 to 1.5 msec. If it is 0.3 msec or more, the production cost of the power supply is lowered. When it is 2 msec or less, the uniformity of pits becomes more excellent. In the triangular wave, the current rise time can be arbitrarily selected.

The duty of alternating current (time during which the aluminum plate in one cycle is an anode / time of one cycle) is preferably 0.25 to 0.5, and more preferably 0.33 to 0.5. preferable.
The AC frequency is preferably 10 to 200 Hz, more preferably 20 to 150 Hz, and still more preferably 30 to 120 Hz. When the frequency is 10 Hz or more, it is difficult to form large faceted pits and the stain resistance is more excellent. If it is 200 Hz or less, it is difficult to be influenced by the inductance component of the circuit through which the electrolytic current flows, and it becomes easy to manufacture a large-capacity power supply.

<Third etching process>
The third etching process performed after the second electrochemical roughening process is formed by dissolving the smut generated by the second electrochemical roughening process and by the second electrochemical roughening process. It is performed for the purpose of dissolving the edge portion of the formed pit.
The third etching process is basically the same as the first etching process, but the etching amount is preferably 0.01 g / m ² or more, more preferably 0.1 g / m ² or more. but preferably not more 10 g / m ² or less, more preferably 0.3 g / m ² or less.

<Third desmut treatment>
After the third etching process, it is preferable to perform pickling (third desmut process) in order to remove dirt (smut) remaining on the surface. The third desmut process is basically the same as the first desmut process.
In the third desmutting treatment, when the same type of electrolyte as that used in the subsequent anodizing treatment is used as the desmutting treatment, it is possible to omit the draining and washing with a nip roller after the desmutting treatment.
The third desmut treatment is preferably performed in an electrolytic cell in which an aluminum plate is subjected to a cathode reaction treatment in an anodizing treatment apparatus used for anodizing treatment described later. If it does in this way, since it becomes unnecessary to provide an independent desmut processing tank for the 3rd desmut processing, equipment cost can be reduced.

<Anodizing treatment>
The aluminum plate treated as described above is further subjected to 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.

  Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the second and third components may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cation such as ammonium ion; anion such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10,000 ppm It may be contained at a concentration of about.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜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 electrolyte is conducted using the same method as in the case of nitric acid electrolysis described above, and the conductivity, specific gravity and temperature, or conductivity and ultrasonic wave propagation corresponding to the matrix of sulfuric acid concentration and aluminum ion concentration. It is preferable to control by speed and temperature.

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

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied.
When a direct current is applied to the aluminum plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case of continuous anodizing treatment, at the beginning of anodizing treatment, so as not to cause so-called “burn” (part where the film becomes thicker than the surrounding area) due to current concentration on a part of the aluminum plate, It is preferable to increase the current density to 30 to 50 A / dm ² or higher as the anodic oxidation process proceeds with a current flowing at a low current density of 5 to 10 A / m ² .
Specifically, it is preferable that the current distribution of the DC power supply is set so that the current of the downstream DC power supply is equal to or greater than the current of the upstream DC power supply. By using such current distribution, so-called burning is less likely to occur, and as a result, high-speed anodization can be performed.

When the anodizing process is continuously performed, it is preferable to perform the liquid feeding method in which the aluminum plate is fed with an electrolyte.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. it is a 800 pieces / μm ² about.

The amount of the anodized film is preferably 1 to 5 g / m ² . When it is 1 g / m ² or more, the plate is hardly damaged. If it is 5 g / m ² or less, a large amount of electric power is not required for production, which is economically advantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable to carry out so that the difference in the amount of the anodized film between the center portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.
Moreover, it is preferable that the quantity of the anodic oxide film of the back surface of the surface which performed the electrochemical roughening process is 0.1-1 g / m < ² >. When it is 0.1 g / m ² or more, the back surface is less likely to be damaged, and the image recording layer that comes into contact with the back surface is less likely to be damaged when stacked as a lithographic printing plate precursor. When it is 1 g / m ² or less, it is economically advantageous.

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.
Among these, the apparatus shown in FIG. 5 is preferably used. FIG. 5 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum plate.

  In the anodizing apparatus 410 shown in FIG. 5, in order to energize the aluminum plate 416 via the electrolytic solution, a feeding tank 412 is provided on the upstream side in the traveling direction of the aluminum plate 416 and an anodizing tank 414 is provided on the downstream side. It is installed. The aluminum plate 416 is conveyed by the pass rollers 422 and 428 as indicated by arrows in FIG. In the feed tank 412 into which the aluminum plate 416 is first introduced, an anode 420 connected to the positive electrode of the DC power supply 434 is installed, and the aluminum plate 416 serves as a cathode. Therefore, a cathode reaction occurs in the aluminum plate 416.

In the anodizing tank 414 into which the aluminum plate 416 is subsequently introduced, a cathode 430 connected to the negative electrode of the DC power source 434 is installed, and the aluminum plate 416 serves as an anode. Therefore, an anodic reaction occurs in the aluminum plate 416, and an anodic oxide film is formed on the surface of the aluminum plate 416.
The distance between the aluminum plate 416 and the cathode 430 is preferably 50 to 200 mm. Aluminum is used as the cathode 430. The cathode 430 is preferably not an electrode having a large area but an electrode divided into a plurality of pieces in the traveling direction of the aluminum plate 416 so that hydrogen gas generated by the anode reaction can be easily released from the system. .

  Between the power supply tank 412 and the anodizing tank 414, it is preferable to provide a tank called an intermediate tank 413 in which the electrolytic solution does not accumulate as shown in FIG. By providing the intermediate tank 413, current can be prevented from bypassing from the anode 420 to the cathode 430 without passing through the aluminum plate 416. It is preferable to reduce the bypass current as much as possible by installing a nip roller 424 in the intermediate tank 413 to drain the liquid. The electrolyte discharged by draining is discharged out of the anodizing apparatus 410 from the drain port 442.

  The electrolyte solution 418 stored in the power supply tank 412 has a higher temperature and / or higher concentration than the electrolyte solution 426 stored in the anodizing tank 414 in order to reduce voltage loss. In addition, the composition, temperature, and the like of the electrolytic solutions 418 and 426 are determined from the formation efficiency of the anodized film, the micropore shape of the anodized film, the hardness of the anodized film, the voltage, the cost of the electrolytic solution, and the like.

  Electrolyte is ejected from the liquid supply nozzles 436 and 438 and supplied to the power supply tank 412 and the anodizing treatment tank 414. For the purpose of keeping the distribution of the electrolyte constant and preventing local current concentration of the aluminum plate 416 in the anodizing tank 414, the liquid supply nozzles 436 and 438 are provided with slits, and the liquid flow to be ejected in the width direction. It has a constant structure.

  In the anodizing bath 414, a shielding plate 440 is provided on the opposite side of the aluminum plate 416 from the anode 430, and current flows to the opposite side of the surface of the aluminum plate 416 where the anodized film is to be formed. Deter. The distance between the aluminum plate 416 and the shielding plate 440 is preferably 5 to 30 mm. It is preferable to use a plurality of DC power supplies 434 and connect the positive electrode sides in common. Thereby, the current distribution in the anodizing bath 414 can be controlled.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. By performing the sealing treatment, the developability (sensitivity) of the lithographic printing plate precursor can be improved.
It is well known that the anodized film is a porous film having pores called pores in a direction substantially perpendicular to the film surface. In the present invention, it is preferable to subject the anodizing treatment to a sealing treatment with a high sealing ratio. The sealing rate is preferably 50% or more, more preferably 70% or more, and still more preferably 90% or more. Here, the “sealing rate” is defined by the following formula.

  Sealing rate = (surface area before sealing−surface area after sealing) / surface area before sealing × 100%

  The surface area can be measured using, for example, a simple BET surface area measuring device (for example, QUANTASORB (manufactured by Kantha Sorb), manufactured by Yuasa Ionics).

  The sealing treatment is not particularly limited, and a conventionally known method can be used. For example, hydrothermal treatment, boiling water treatment, steam treatment, dichromate treatment, nitrite treatment, ammonium acetate salt treatment, electrodeposition sealing treatment, and the like described in JP-B 36-22063. Zirconate treatment, treatment with an aqueous solution containing a phosphate and an inorganic fluorine compound described in JP-A-9-244227, treatment with an aqueous solution containing a sugar described in JP-A-9-134002 , Treatment with an aqueous solution containing titanium and fluorine described in JP-A-2000-81704 and JP-A-2000-89466, alkali metal silica described in US Pat. No. 3,181,461, etc. Examples include acid salt treatment.

  An example of a suitable sealing treatment is an alkali metal silicate treatment. The alkali metal silicate treatment is performed using an alkali metal silicate aqueous solution having a pH of 10 to 13 at 25 ° C. without causing gelation of the liquid and dissolution of the anodized film. The processing conditions such as the processing time can be selected as appropriate. Suitable alkali metal silicates include, for example, sodium silicate, potassium silicate, and lithium silicate. Moreover, sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. can be mix | blended in order to adjust pH of alkali metal silicate aqueous solution high.

Furthermore, you may mix | blend alkaline-earth metal salt and / or a group 4 (Group IVA) metal salt with alkali metal silicate aqueous solution as needed. Examples of the alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates, hydrochlorides, phosphates, acetates, oxalates, and boric acids of alkaline earth metals. Examples thereof include water-soluble salts such as salts. 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. Alkaline earth metal salts and Group 4 (Group IVA) metal salts can be used alone or in combination of two or more.
The concentration of the alkali metal silicate aqueous solution is preferably 0.01 to 10% by mass, and more preferably 0.05 to 5.0% by mass.

Another example of a suitable sealing treatment is a fluorinated zirconate treatment. The fluorinated zirconate treatment is performed using a fluorinated zirconate salt such as sodium fluorinated zirconate or potassium fluorinated zirconate. Among these, it is preferable to use sodium fluorinated zirconate. Thereby, the developability (sensitivity) of the lithographic printing plate precursor becomes excellent. The concentration of the fluorinated zirconic acid solution used for the fluorinated zirconic acid treatment is preferably 0.01 to 2% by mass, and more preferably 0.1 to 0.3% by mass.
The fluorinated zirconate solution preferably contains sodium dihydrogen phosphate. The concentration of sodium dihydrogen phosphate is preferably 0.01 to 3% by mass, and more preferably 0.1 to 0.3% by mass.
The fluorinated zirconate solution may contain aluminum ions. In that case, the aluminum ion concentration of the fluorinated zirconate solution is preferably 1 to 500 mg / L.

The temperature for the sealing treatment is preferably 20 to 90 ° C, and more preferably 50 to 80 ° C.
The sealing treatment time (immersion time in the solution) is preferably 1 to 20 seconds, and more preferably 5 to 15 seconds.

  In addition, after sealing as necessary, a polymer or copolymer having the above-mentioned alkali metal silicate treatment, polyvinylphosphonic acid, polyacrylic acid, sulfo group or the like in the side chain, Japanese Patent Application Laid-Open No. 11-231509 A surface treatment such as a treatment of immersing or coating in a solution containing an organic compound or a salt thereof having an amino group and a group selected from the group consisting of a phosphine group, a phosphone group, and a phosphate group described in the publication be able to.

  After the sealing treatment, it is preferable to perform a hydrophilic treatment described later.

<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. 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 Phosphoric acid modified starch, diamine compounds described in JP-A-63-056498, inorganic or organic acids of amino acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing a carboxy group or hydroxy group, compounds having an amino group and a 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, 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.

The hydrophilization treatment by forming a hydrophilic undercoat layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491.
Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, sulfo group-containing vinyl polymerizable compounds such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Examples of hydrophilic compounds that may be used in this method include, -NH ₂ group, compounds having at least one selected from the group consisting of -COOH group and sulfo group.

<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 1 second or longer, more preferably 2 seconds or longer, more preferably 20 seconds or shorter, and even more preferably 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”), a negative photosensitive composition containing a diazo resin or a photocrosslinking resin (hereinafter also referred to as “conventional negative type”), and a positive photosensitive composition containing a quinonediazide compound. Product (hereinafter also referred to as “conventional positive type”), a photosensitive composition that does not require a special development step (hereinafter referred to as “the conventional positive type”). 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 from the viewpoint 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, a dissolution inhibitor as described in JP-A-2001-305722, [0053] to [0055] is 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>
An intermediate layer is preferably provided 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 photothermal 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 a novolak resin and a polymer 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 photopolymerization initiators can be appropriately selected depending on the wavelength of the light source to be used. For example, the initiation system described in JP-A-2001-22079, [0021] to [0023] is preferable.
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 the 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 these, a photosensitive composition containing a diazo resin and an alkali-soluble or swellable polymer compound (binder) is preferable.
Examples of the diazo resin include condensates of aromatic diazonium salts and active carbonyl group-containing compounds such as formaldehyde; condensates of p-diazophenylamines and formaldehyde with hexafluorophosphate or 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 produce a lithographic printing plate. It is preferable to obtain.
The developer is preferably an alkaline developer, and more preferably an alkaline aqueous solution that does not substantially contain 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.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Manufacture of roll for embossing of aluminum plate The following treatments (1) to (5) were sequentially performed using a roll made of hardened tool steel (SKD11) to Hv750 to obtain each roll for embossing of aluminum plate.

(1) Mirror polishing treatment A buffing treatment was performed as a mirror polishing treatment to remove traces of the grindstone that polished the roll surface. On the surface after polishing, the average roughness _Ra was 0.2 μm, and the maximum height R _max was 1 μm. The average roughness R _a and the maximum height R _max were measured according to the measurement of the arithmetic average roughness R _a and the maximum height R _y of JIS B0601-1994 respectively.

(2) Blasting treatment The surface of the roll was roughened by performing an air blasting process using # 80 mesh alumina particles as a grid material twice. The spray pressure was 2 kgf / cm ² (1.96 × 10 ⁵ Pa) for each time of the air blast method. On the surface after the blast treatment, the average roughness _Ra was 0.8 μm.

(3) Degreasing treatment It was immersed in a degreasing tank with a liquid temperature of 30 ° C. for 30 seconds, and the oil on the surface was removed with the degreasing solution. Then, it washed with water, air was sprayed, and the water | moisture content was removed.

(4) Electrolytic treatment In an electrolytic solution containing chromic acid 300 g / L, sulfuric acid 2 g / L, and iron 1 g / L at a liquid temperature of 50 ° C., continuous DC current is applied and electrolysis is performed at a current density of 30 A / dm ^{2 using} the roll as the anode. Processed. Electric quantity of electrolytic treatment was 20,000C / dm ^2.
The current waveform used was a three-phase full-wave rectification and a direct current with a ripple component of 5% or less through a filter circuit. The counter electrode was lead. The roll was placed vertically in the electrolytic solution, and a lead electrode was arranged in a cylindrical shape so as to surround the periphery. The shaft portion of the roll was masked with vinyl chloride so that no electrolytic treatment was performed.

(5) Chromium plating treatment Next, a continuous direct current was applied in an electrolytic solution containing chromic acid 300 g / L, sulfuric acid 2 g / L, and iron 1 g / L at a temperature of 50 ° C., and the current density was 40 A / a plating treatment was carried out at dm ^2. The plating treatment time was set so that the plating thickness was 8 μm.
The current waveform used was a three-phase full-wave rectification and a direct current with a ripple component of 5% or less through a filter circuit. The counter electrode was lead. The roll was placed vertically in the electrolyte, and a lead electrode was arranged in a cylindrical shape so as to surround the periphery. The shaft portion of the roll was masked with vinyl chloride so as not to be plated.

2. Manufacture of an aluminum plate Each component (mass%) shown in Table 1 is contained, and the balance is prepared by using an aluminum alloy composed of Al and inevitable impurities. An ingot having a thickness of 500 mm and a width of 1200 mm was prepared by a DC casting method. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, the temperature was kept constant at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing at 500 degreeC using a continuous annealing machine, it cold-rolled and finished to thickness 0.3mm and width 1060mm, and obtained the aluminum plates 1-3.
Moreover, in cold rolling, the aluminum plates 4-6 were each obtained by the method similar to each of the aluminum plates 1-3 except having used the roll for aluminum plate embossing obtained above.

3. Production of lithographic printing plate support (Examples 1 to 20 and Comparative Example 1)
The aluminum plate obtained above was subjected to the following surface treatment to obtain each lithographic printing plate support shown in Table 2.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (a) to (j).

(A) Etching treatment in alkaline aqueous solution (first etching treatment)
Etching 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. onto the aluminum plate from the spray tube. The etching amount of the surface subjected to the electrochemical roughening treatment after the aluminum plate was as shown in Table 2.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(B) Desmutting treatment in an acidic aqueous solution An aluminum plate was sprayed with an aqueous solution having a sulfuric acid concentration of 170 g / L, an aluminum ion concentration of 5 g / L, and a temperature of 50 ° C. from a spray tube to perform desmutting treatment for 5 seconds. As the sulfuric acid aqueous solution, the waste liquid of the (i) anodizing treatment step described later was used.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(C) Electrochemical roughening treatment using alternating current in acidic aqueous solution (first electrochemical roughening treatment)
As an electrolytic solution, a solution (temperature 35 ° C.) in which aluminum chloride is adjusted to 5 g / L by adding aluminum chloride to an aqueous solution having a hydrochloric acid concentration of 7.5 g / L, and the current is controlled by inverter control using an IGBT element. Then, an electrochemical surface roughening process was performed using a power source capable of generating an alternating current having an arbitrary waveform. The alternating current waveform, current rise time, duty, and frequency were as shown in Table 2, respectively.
In the first electrochemical graining treatment, the current density during the anodic reaction of the aluminum plate at the peak of the alternating current was 100A / dm ^2.
The amount of electricity was the sum of the amount of electricity at the time of anode of the aluminum plate, as shown in Table 2. Further, the current ratio (ratio of the total amount of electricity when the aluminum plate was the anode and the total amount of electricity when the aluminum plate was the cathode) was as shown in Table 2.
The concentration control of the electrolyte is controlled by adding hydrochloric acid and water in proportion to the energization amount according to the data table determined in advance, and the liquid composition (hydrochloric acid concentration and aluminum ion concentration) determined in advance and the propagation speed of ultrasonic waves in the liquid. A multi-component concentration measurement was performed using a data table in which the relationship between the liquid conductivity and the liquid conductivity was obtained, and a method of correcting the addition amount of hydrochloric acid and water was used from the result.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(D) Etching treatment in alkaline aqueous solution (second etching treatment)
Etching was performed by spraying an aqueous solution of caustic soda concentration of 370 g / L, aluminum ion concentration of 100 g / L, and a temperature of 35 ° C. onto the aluminum plate from a spray tube. The etching amount of the surface of the aluminum plate subjected to the electrochemical roughening treatment was as shown in Table 2.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(E) Desmutting treatment in an acidic aqueous solution An aluminum plate was sprayed with an aqueous solution having a sulfuric acid concentration of 170 g / L, an aluminum ion concentration of 5 g / L, and a temperature of 50 ° C. from a spray tube to perform desmutting treatment for 5 seconds. As the sulfuric acid aqueous solution, the waste liquid of the (i) anodizing treatment step described later was used.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(F) Electrochemical roughening treatment using alternating current in acidic aqueous solution (second electrochemical roughening treatment)
As an electrolytic solution, a solution in which aluminum chloride is added to an aqueous solution having a hydrochloric acid concentration of 5 g / L to adjust the aluminum ion concentration to 5 g / L (temperature 35 ° C.) is used, and the current is controlled by inverter control using an IGBT element. An electrochemical surface roughening treatment was performed using a power source capable of generating an alternating current having an arbitrary waveform. The alternating current waveform, current rise time, duty, and frequency were as shown in Table 2, respectively.
In the second electrochemical surface roughening treatment, the current density during the anode reaction of the aluminum plate at the peak of alternating current was 80 A / dm ² .
The amount of electricity was the sum of the amount of electricity at the time of anode of the aluminum plate, as shown in Table 2. Further, the current ratio (ratio of the total amount of electricity when the aluminum plate was the anode and the total amount of electricity when the aluminum plate was the cathode) was as shown in Table 2.
The concentration control of the electrolyte is controlled by adding hydrochloric acid and water in proportion to the energization amount according to the data table determined in advance, and the liquid composition (hydrochloric acid concentration and aluminum ion concentration) determined in advance and the propagation speed of ultrasonic waves in the liquid. A multi-component concentration measurement was performed using a data table in which the relationship between the liquid conductivity and the liquid conductivity was obtained, and a method of correcting the addition amount of hydrochloric acid and water was used from the result.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(G) Etching treatment in alkaline aqueous solution (third etching treatment)
An etching process was performed by spraying an aqueous solution of caustic soda concentration of 50 g / L, aluminum ion concentration of 5 g / L, and temperature of 35 ° C. on the aluminum plate from the spray tube. The etching amount of the surface of the aluminum plate subjected to the electrochemical roughening treatment was as shown in Table 2.
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(H) Desmutting treatment in an acidic aqueous solution An aluminum plate was sprayed with an aqueous solution having a sulfuric acid concentration of 170 g / L, an aluminum ion concentration of 5 g / L, and a temperature of 50 ° C. from a spray tube to perform desmutting treatment for 5 seconds. As the sulfuric acid aqueous solution, the waste liquid of the (i) anodizing treatment step described later was used.
Then, the liquid was drained with a nip roller. After draining, it was subjected to (i) anodizing treatment step without performing water washing treatment.

(I) Anodizing treatment As an electrolytic solution, an electrolytic solution (temperature: 50 ° 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 oxide film amount was 2.7 g / m ² .
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller.

(J) Hydrophilization treatment The aluminum plate was immersed in a 2.5% by weight aqueous solution of sodium silicate (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 .
Then, the liquid was drained with a nip roller, and further washed with water for 5 seconds using a spray tube having a spray tip in which spray water spread in a fan shape, and further drained with a nip roller. Furthermore, 90 degreeC wind was sprayed for 10 seconds, it was made to dry, and the support body for lithographic printing plates was obtained.

(Comparative Example 2)
(F) The electrolytic solution used in the electrochemical surface roughening treatment (second electrochemical surface roughening treatment) using alternating current in an acidic aqueous solution is added to the aqueous solution having a nitric acid concentration of 10 g / L and aluminum nitrate is added. Then, a lithographic printing plate support was obtained in the same manner as in Example 1 except that the liquid having an aluminum ion concentration of 5 g / L was used.

4). Observation of the surface of a lithographic printing plate support The surface shape of the lithographic printing plate support obtained in Examples 1 to 34 was measured with a scanning electron microscope (JSM-5500, manufactured by JEOL Ltd., the same shall apply hereinafter) at a magnification of 50000. When observed at a magnification, fine irregularities having a diameter of 0.1 to 0.2 μm were uniformly and densely formed on the surface. Further, when observed with a scanning electron microscope at a magnification of 2000, irregularities having a diameter of 1 to 20 μm were formed on the surfaces of these lithographic printing plate supports. Fine irregularities having a diameter of 0.1 to 0.2 μm were generated by being superimposed on irregularities having a diameter of 1 to 20 μm. Moreover, the unevenness | corrugation of 1-20 micrometers in diameter was produced | generated independently, without overlapping generally, and was uniform. Moreover, there were few plateau parts on the surface.
On the other hand, when the surface shape of the lithographic printing plate support obtained in Comparative Example 1 was observed in the same manner, fine irregularities with a diameter of 0.1 to 0.2 μm and diameters of 1 to 20 μm were observed on the surface. Concavities and convexities were generated, but the concavities and convexities with a diameter of 1 to 20 μm had a nonuniform distribution of depth and pit diameter compared to the case of the example. Moreover, many plateau parts existed on the surface.

5. Preparation of lithographic printing plate precursor A lithographic printing plate precursor was obtained by providing each lithographic printing plate support obtained above with a thermal positive type image recording layer as follows. Before providing the image recording layer, an undercoat layer was provided as described later.

On the lithographic printing plate support, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds to form a coating film of an undercoat layer. The coating amount of the coating film after drying was 15 mg / m ² .

<Undercoat liquid composition>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1g

Furthermore, a heat-sensitive layer coating solution having the following composition was prepared, and the coating amount after drying the heat-sensitive layer coating solution (heat-sensitive layer coating amount) on a lithographic printing plate support provided with an undercoat layer was 1.8 g / m. ² was applied and dried to form a heat sensitive layer (thermal positive type image recording layer) to obtain a lithographic printing plate precursor.

<Thermosensitive layer coating solution composition>
Novolak resin (m-cresol / p-cresol = 60/40, weight average molecular weight 7,000, containing 0.5% by mass of unreacted cresol) 0.90 g
-Ethyl methacrylate / isobutyl methacrylate / methacrylic acid copolymer (molar ratio 35/35/30) 0.10 g
-Cyanine dye A 0.1 g represented by the following structural formula
・ Tetrahydrophthalic anhydride 0.05g
・ 0.002 g of p-toluenesulfonic acid
-Ethyl violet counter ion with 6-hydroxy-β-naphthalenesulfonic acid 0.02 g
-Fluorosurfactant (Defenser F-780F, manufactured by Dainippon Ink & Chemicals, Inc., solid content 30% by mass) 0.0045 g (solid content conversion)
・ Fluorosurfactant (Defenser F-781F, manufactured by Dainippon Ink & Chemicals, Inc., solid content: 100% by mass) 0.035 g
・ Methyl ethyl ketone 12g

6). Evaluation of planographic printing plate precursor The printing durability, cleaner resistance (chemical resistance) and stain resistance of the planographic printing plate were evaluated by the following methods.
(1) Printing durability The obtained lithographic printing plate precursor was imaged using a TrendSetter manufactured by Creo at a drum rotation speed of 150 rpm and a beam intensity of 10 W.
Thereafter, using a PS processor 940H manufactured by Fuji Photo Film Co., Ltd. charged with an alkaline developer having the following composition, the solution was maintained at 30 ° C. and developed for 20 seconds to obtain a lithographic printing plate. The sensitivity of all the lithographic printing plate precursors was good.

<Alkali developer composition>
・ D-Sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether (weight average molecular weight 1,000)
0.5% by mass
・ Water 96.15% by mass

The obtained lithographic printing plate was printed on a Lithrone printing machine manufactured by Komori Corporation using DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc. The printing durability was evaluated based on the number of printed sheets when visually recognized.
The results are shown in Table 2. The meanings of the symbols in Table 2 are as follows.
A: 30,000 or more A-B: 20,000 or more and less than 30,000 B: 10,000 or more and less than 20,000 C: less than 10,000

(2) Cleaner resistance (chemical resistance)
The evaluation of printing durability in (1) above was performed except that a multi-cleaner manufactured by Fuji Photo Film Co., Ltd. was applied to the surface of the image recording layer for 1 minute and then wiped with water every 5000 sheets during printing. Similarly, cleaner resistance was evaluated based on the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing. Here, cleaner resistance was used as a kind of printing durability evaluation method.
The results are shown in Table 2. The meanings of the symbols in Table 2 are as follows.
A: 10,000 sheets or more A-B: 6,000 sheets or more and less than 10,000 sheets B: 3,000 sheets or more and less than 6,000 sheets C: Less than 3,000 sheets

(3) Stain resistance Using a lithographic printing plate obtained in the same manner as in the evaluation of printing durability, a DIC-GEOS (s) red ink was applied using a Mitsubishi diamond F2 printer (manufactured by Mitsubishi Heavy Industries). After printing, the blanket stain after printing 10,000 sheets was visually evaluated.
The results are shown in Table 2. The meanings of the symbols in Table 2 are as follows.
A: The blanket is hardly dirty. AB: The blanket is slightly dirty. B: The blanket is dirty but within the allowable range.

As is apparent from Table 2, all the lithographic printing plates using the lithographic printing plate support obtained by the method for producing a lithographic printing plate support according to the present invention (Examples 1 to 20) were subjected to printing durability. Excellent in soil resistance and stain resistance.
On the other hand, when the AC waveform used for the first electrochemical surface roughening treatment is a trapezoidal wave (Comparative Example 1), the lithographic printing plate using the obtained lithographic printing plate support has a printing durability. It was inferior in property and stain resistance. Further, when the electrolytic solution used for the second electrochemical surface roughening treatment is an aqueous nitric acid solution (Comparative Example 2), the lithographic printing plate using the obtained lithographic printing plate support has printing durability, It was inferior in cleaner resistance and dirt resistance.

It is typical sectional drawing of the apparatus which performs the water washing process with the free-fall curtain-like liquid film used for the water washing process in the manufacturing method of the lithographic printing plate support of this invention. It is a graph which shows an example of the triangular waveform current waveform figure used for the 1st electrochemical roughening process in the manufacturing method of the support body for lithographic printing plates of this invention. It is a graph which shows an example of the alternating waveform current waveform figure used for the 2nd electrochemical roughening process in the manufacturing method of the support body for lithographic printing plates of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in the manufacturing method of the support body for lithographic printing plates of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in the manufacturing method of the support body for lithographic printing plates of this 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 40 Main electrolytic cell 50 Auxiliary anode tank 100 Free Apparatus for washing with water using falling curtain-like liquid film 102 Water 104 Water storage tank 106 Water supply cylinder 108 Rectifier 410 Anodizing apparatus 412 Power supply tank 413 Intermediate tank 414 Anodizing tank 416 Aluminum plate 418, 426 Electrolyte 420 Anode 422 428 Pass roller 424 Nip roller 430 Cathode 434 DC power supply 436, 438 Liquid supply nozzle 440 Shielding plate 442 Drain port

Claims (3)

  The aluminum plate is subjected at least to an electrochemical surface roughening treatment using triangular wave alternating current in an aqueous solution containing hydrochloric acid and an electrochemical surface roughening treatment using alternating current in an aqueous solution containing hydrochloric acid. A method for producing a lithographic printing plate support, which is applied in order to obtain a lithographic printing plate support.   2. The planographic printing plate according to claim 1, wherein a time until the current reaches a peak from zero on the side where the aluminum plate of the triangular wave becomes an anode is ¼ or less of a time when the aluminum plate becomes an anode. A method for producing a support.   The manufacturing method of the support body for lithographic printing plates of Claim 1 or 2 with which the said aluminum plate has an uneven | corrugated pattern on the surface.

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