JP2005089846A - Aluminum alloy plate stock for planographic printing plate, and support for the planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy plate stock capable of yielding a uniform, electrolytically roughened face by electrochemical roughening treatment and capable of giving an excellent planographic printing plate at a reduced production cost, in a reduced time and in a simplified production process. <P>SOLUTION: The aluminum alloy plate stock for a planographic printing plate is a continuously cast rolled plate consisting of an aluminum alloy. The aluminum alloy plate stock comprises 0.20 to 0.80 mass% Fe, and the balance aluminum and crystal grain refining elements with inevitable impurity elements. In the impurity elements, the content of Si is 0.02 to 0.30 mass% and the content of Cu is ≤0.05 mass%, and the solid solution content of Si is 150 to 1,500 ppm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an aluminum alloy base plate for a lithographic printing plate excellent in electrochemical roughening characteristics, an aluminum alloy support for a lithographic printing plate, and a method for producing the same.

Photosensitive lithographic printing plate precursors using an aluminum plate as a support are widely used for offset printing.
Generally, as an aluminum alloy base plate used for a lithographic printing plate support, a rolled plate having a thickness of 0.1 to 0.5 mm is conventionally used.
As the Al material used here, a JIS1000 material or a JIS3000 material is often used.

  Such an aluminum alloy rolled plate is manufactured by removing the surface of an ingot obtained by semi-continuous casting (DC casting) by grinding, performing homogenization treatment as necessary, and then hot-heating at a predetermined temperature. It was a general method that has been conventionally performed to perform rolling, then or during the course of cold rolling, heat treatment called intermediate annealing, and then final cold rolling.

  As a method for producing a lithographic printing plate precursor, generally, a surface of a sheet-shaped or coil-shaped aluminum plate is subjected to a roughening treatment and anodizing treatment to obtain a lithographic printing plate support, There is known a method in which an image recording layer is formed by applying a photosensitive solution to the substrate and drying it, and cutting it to a desired size if necessary. This lithographic printing plate precursor is subjected to a development process after image printing to form a lithographic printing plate.

In this method, in order to improve the adhesion between the image recording layer and the support, the surface roughening treatment is carried out electrochemically in an acidic solution (also referred to as “electrolytic surface roughening treatment” in the present invention). It is also effective to perform surface treatment and application of a primer solution after the anodizing treatment.
When the roughening treatment including the electrolytic roughening treatment is performed, minute irregularities (pits) are generated on the surface of the support. Conventionally, by making the diameter uniform and large, and by increasing the depth, the adhesiveness between the recording layer and the support is strengthened in the image area, and even if a large number of sheets are printed, the recording layer It is considered that a lithographic printing plate precursor that does not peel off and can retain a large amount of dampening water on the surface in non-image areas, is less likely to cause stains, and has excellent printability. It was. For example, Patent Documents 1 to 3 propose methods for improving the shape and uniformity of electrolytic roughening pits from such a viewpoint.

  However, all of these methods have been studied for materials with high Al purity, and cannot be applied to Al materials with many alloy components.

In the case of a large amount of alloy components, in claim 1 of Patent Document 4, an aluminum alloy continuous cast and rolled plate containing 0.20 to 0.80 mass% Fe, with the balance being aluminum and a grain refinement element , And inevitable impurity elements, of which the Si content is 0.3 mass% or less and the Cu content is 0.05 mass% or less, and the solid solution amount of Fe is 250 ppm or less, It is described that the aluminum surface plate for an electrolytic surface-roughened lithographic printing plate, characterized in that the solid solution amount of Si is 150 ppm or less and the solid solution amount of Cu is 120 ppm or less, is excellent in electrolytic surface roughness. ing.
However, alloy component elements consist of those that dissolve in Al, those that precipitate as metal components, and those that exist as intermetallic compounds, and the amount of intermetallic compounds must be below a predetermined amount. Thus, keeping the solid solution amount of Fe, Si, Cu low causes an increase in the amount of precipitated components, and there is a problem of causing defects such as deterioration of the resistance to severe ink stains. Moreover, it is difficult to keep the solid solution amount low while crystallizing the second phase particles uniformly and finely. Here, “severe ink stains” appear on printed paper as a result of ink becoming more likely to adhere to the non-image area surface portion of a lithographic printing plate when printing is interrupted many times. This refers to dot-like or annular dirt.
Further, a lithographic printing plate excellent in handleability in which the rolling direction of an aluminum rolled plate can be easily discriminated is described in the prior art (Patent Document 5).

JP 2000-108534 A JP 2000-37965 A JP 2000-37964 A JP-A-7-173563 (corresponding EP publication gazette, EP0640669) JP 2002-79770 A

  In the prior art, a lithographic printing plate support in which a uniform electrolytic roughened surface is obtained on an Al plate having a high content of alloying elements, and the manufacturing process can be simplified and the manufacturing cost and manufacturing time are reduced. Was not obtained.

  Accordingly, one of the objects of the present invention is to provide a continuous cast rolled aluminum alloy base plate that can obtain a lithographic printing plate having a uniform electrolytic roughened surface and good printing durability. Another object of the present invention is to provide an aluminum alloy base plate that simplifies the manufacturing process and reduces manufacturing cost and manufacturing time, and is capable of obtaining a lithographic printing plate having excellent printing durability and stain resistance. A plate support is provided.

The present invention provides an aluminum alloy base plate suitable for the following electrolytic surface roughening.
(1) An aluminum alloy continuous cast and rolled plate containing 0.20 to 0.80 mass% Fe, the balance being made of aluminum, a grain refinement element, and an inevitable impurity element, The lithographic printing is characterized in that the Si content is 0.02 to 0.30% by mass and the Cu content is 0.05% by mass or less, and the solid solution amount of Si is 150 ppm to 1500 ppm. Aluminum alloy base plate for plate.
(2) An aluminum alloy base plate for a lithographic printing plate, preferably having a solid solution amount of Fe of 250 ppm to 4000 ppm.
(3) Preferably, the aluminum alloy base plate for a lithographic printing plate, wherein the solid solution amount of Cu is 100 ppm or more and 500 ppm or less.
(4) An aluminum alloy base plate for a lithographic printing plate having a specific resistance of 6.5 to 3.5 μΩmm measured at a liquid nitrogen temperature.

The present invention also provides the following.
(5) A lithographic printing plate support obtained by subjecting the aluminum alloy base plate for a lithographic printing plate according to any one of (1) to (4) above to a roughening treatment including electrochemical roughening.
(6) After the surface roughening treatment including the electrochemical surface roughening is performed at an electric current density of 5 A / dm ² or more and electrochemical surface roughening treatment, 0.1 g / m ² or more of Al is chemically treated. The support for a lithographic printing plate as described in (5) above, which dissolves automatically.

(7) The lithographic printing plate support according to (6), wherein the electrochemical surface roughening treatment is a treatment using an alternating current having a trapezoidal waveform in an electrolytic solution containing nitric acid.
(8) The lithographic printing plate support according to (6), wherein the electrochemical surface roughening treatment is treatment using an alternating current having a sinusoidal waveform in an electrolyte containing hydrochloric acid.
(9) The surface roughening treatment including the electrochemical surface roughening treatment is a first electrochemical surface roughening treatment, and the total amount of electricity in the anode reaction in the electrolytic solution containing nitric acid is 65 to 500 C / dm. ² and 0.1 g / m ² or more of Al is chemically dissolved, and then the second electrolytic surface roughening treatment is performed in an electrolytic solution containing hydrochloric acid in a total amount of electricity of 25 to 100 C / dm ² in the anodic reaction. The lithographic printing plate support according to any one of the above (5) to (8), which is prepared by the following step, and thereafter 0.03 g / m ² or more of Al is chemically dissolved.

The present invention also provides the following lithographic printing plate precursors.
(10) A lithographic printing plate precursor having a recording layer on one surface of the lithographic printing plate support according to any one of (5) to (9).
(11) A lithographic printing plate having a recording layer on one side of the lithographic printing plate support according to any one of (5) to (9) and having a wood grain pattern or stripe pattern on the other side Original edition.

When the aluminum alloy base plate for a lithographic printing plate of the present invention is subjected to an electrochemical roughening treatment, a uniform electrolytic roughened surface is obtained, and an excellent support for a lithographic printing plate is obtained. When this lithographic printing plate support is used as a lithographic printing plate precursor, the quality such as good printing durability is excellent.
In addition, the method for producing an aluminum alloy base plate for a lithographic printing plate of the present invention that can be an excellent lithographic printing plate precursor as described above has a simplified production process as compared with the conventional method, reducing the production cost, There is an advantage that time is shortened and the industrial contribution is extremely large.

Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
<Aluminum alloy base plate (rolled aluminum)>
For the lithographic printing plate support of the present invention, the aluminum alloy base plate of the present invention described below is used. The essential alloy components in the aluminum alloy are Al and Fe, and may contain Si and Cu as impurities.

Si is an element contained as an inevitable impurity in an Al ingot, which is a raw material, in an amount of about 0.03 to 0.1% by mass, and is often intentionally added in a small amount to prevent variation due to a difference in raw materials. Si exists as a solid solution in aluminum, or as an intermetallic compound or a single precipitate.
In the present application, the amount of Si as an alloy component is 0.02 to 0.30% by mass, and a specific amount thereof is solute Si. Si affects the electrolytic surface roughening treatment. The inventors of the present invention pay particular attention to the amount of solid solution, and when carrying out electrochemical surface roughening on an aluminum alloy substrate prepared by continuous casting, it is necessary to keep the amount of solid solution of Si at a certain value or more. It has been found that it exhibits an excellent effect on the stability. When the Si content is 0.02 to 0.30 mass% and the Si solid solution amount is 150 ppm or more and 1500 ppm or less, the electrolytic surface roughening treatment property can be stabilized.
The Si content is set to 0.30% by mass or less because if too much Si impairs the uniformity of electrolytic surface roughening, the content is set to 0.30% by mass or less. Moreover, if the amount is too large, the amount of single Si increases relatively, and when anodization is performed after the surface roughening treatment, defects in the anodized film are likely to occur due to the single Si, and the water retention of the defective portion is increased. This is because the paper is easily soiled during printing.
In the present invention, the solid solution amount of Si is 150 ppm or more and 1500 ppm or less, preferably 300 ppm or more and 1300 ppm or less, in terms of excellent stability of the electrolytic surface roughening treatment.

  Fe has a small amount of solid solution in aluminum, and most remains as an intermetallic compound. Fe has an effect of increasing the mechanical strength of the aluminum alloy, and greatly affects the strength of the support. If the Fe content is too small, the mechanical strength is too low, and it becomes easy to cause plate breakage when the lithographic printing plate is attached to the plate cylinder of a printing press. Further, when printing a large number of copies at high speed, the plate is likely to be cut out similarly. On the other hand, when the Fe content is too high, the strength becomes higher than necessary, and when the lithographic printing plate is attached to the plate cylinder of a printing press, the fitness is inferior, and the plate is easily cut during printing. Further, if the Fe content is more than 1.0% by mass, for example, cracking is likely to occur during rolling. The aluminum base plate of the present invention has an Fe content of 0.20 to 0.80 mass%.

  Fe also affects the electrolytic surface roughening treatment. The present inventors keep the solid solution amount of Fe at a certain value or more in addition to keeping the solid solution amount of Si at a certain value or more when electrochemically roughening an aluminum alloy substrate prepared by continuous casting. I found it desirable. By setting the Fe content to 0.20 to 0.80 mass% and the Fe solid solution amount to 250 ppm or more and 4000 ppm or less, the electrolysis can be further stabilized.

The reason why the Fe content is 0.20% by mass or more is that when the Fe content is too small as described above, the mechanical strength is too low, and the lithographic printing plate is attached to the plate cylinder of the printing press. This is because it becomes easy to cause out of print. Further, when a large number of copies are printed at high speed, the plate is likely to be cut out similarly. If the amount is 0.80% by mass or less, if it is too much, the strength becomes unnecessarily high, and when the planographic printing plate is attached to the plate cylinder of a printing press, it is inferior in fitness and tends to cause plate breakage during printing. Because. Preferably it is 0.20 to 0.50 mass%.
In the present invention, the solid solution amount of Fe is 250 ppm or more and 4000 ppm or less, preferably 300 ppm or more and 1300 ppm or less, in terms of excellent stability of the electrolytic surface roughening treatment.

Cu is an important element in controlling the electrolytic surface roughening treatment. Cu is an element that dissolves very easily, and part of it becomes an intermetallic compound. Since it is preferable for the uniformity of electrolytic surface roughening, it is desirable to contain 0.001% by mass or more.
When the Cu content is more than 0.050% by mass, the diameter of the pits generated by the electrolytic surface-roughening treatment in the nitric acid solution becomes too large and the uniformity of the diameter is lowered, so that the stain resistance is particularly inferior. .
Moreover, the present inventors can make pits having a diameter of 0.5 μm or less generated by electrolytic surface roughening treatment in a hydrochloric acid solution by making the Cu content within this range, and also have a surface area of the support surface. It has been found that the rate of increase of can be maximized. Since the contact area with the image recording layer can be increased by increasing the increase ratio of the surface area, the adhesion is improved, and the printing durability and the cleaner printing durability are excellent. Further, the stain resistance when the planographic printing plate is obtained is excellent. In the present invention, from the above viewpoint, the Cu content is 0.050% by mass or less, preferably 0.001 to 0.030% by mass.
The solid solution amount of Cu is preferably 100 ppm or more and 500 ppm or less.

  The crystal grain refining element may be added as appropriate to prevent cracking during casting. Therefore, for example, Ti can be added in a range of 0.05% by mass or less and B can be added in a range of 0.02% by mass or less.

  The balance of the aluminum plate is made of Al and inevitable impurities. Examples of inevitable impurities contained in the aluminum alloy include Mg, Mn, Zn, Cr, Zr, V, Zn, and Be, and these may be contained in amounts of 0.05% by mass or less, respectively. Most of the inevitable impurities are contained in the Al ingot. If the inevitable impurities are contained in, for example, a metal having an Al purity of 99.7%, the effects of the present invention are not impaired. For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.

  As a result of various studies to solve the problems of the prior art as described above, the present inventor made an aluminum alloy base plate containing a specific amount of a specific alloy element as a continuous cast rolled material, It has been found that the uniformity of the electrolytically roughened surface obtained when the raw plate is electrolytically roughened can be improved by setting the value to a specific value. If the amount of these solid solutions exceeds the upper limit value, large pits having a diameter exceeding 10 μm are easily formed on the electrolytic roughened surface, the water retention is impaired, ink stains occur, and the printing durability in printing deteriorates.

In addition to the solid solution amount of Si, it has been found that preferably the above effect can be further obtained by setting either or both of the solid solution amounts of Fe and Cu to specific values.
Furthermore, it has been found that by setting the heat treatment temperature and time to appropriate values, the Fe, Si, and Cu solid solution amounts of the base plate can be set to appropriate values. In the present invention, in order to obtain an aluminum alloy base plate suitable for an electrolytic surface-roughened lithographic printing plate support, a continuous casting and rolling method is used, and a specific chemical composition and a solid solution amount of Si are set to specific values. preferable.

  Although the preferable manufacturing method of the aluminum alloy base plate of this invention is demonstrated below, this invention is not limited to this. Continuous casting and rolling has a high solidification rate on the surface of the cast material, so that the crystallized material is fine and uniform, and the ingot homogenization heat treatment required by the DC casting method is not required, and it is not subjected to long-time processing. Is stable and suitable as a base plate for a support.

  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. As for 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, but the present invention uses a continuous casting method using a driving mold. preferable.

  As the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a twin belt method (Hazley method), a cooling belt or a cooling block typified by the Al Swiss Caster II type is used. The method is carried out industrially. 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 finished to a predetermined thickness, for example, a thickness of 0.1 to 0.5 mm, through processes such as cold rolling and intermediate annealing. An intermediate annealing treatment may be performed before or after cold 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. 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 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 the productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  The aluminum plate used in the present invention is preferably subjected to H18 tempering as defined in JIS. When the intermediate annealing is omitted, it is preferable to use a temper of H19.

However, in the present invention, preferably, the solid solution amount of an alloy element such as Si is adjusted to a predetermined value by heat treatment after intermediate annealing or final cold rolling. In the present invention, the Si solid solution amount is 150 ppm to 1500 ppm, preferably, the Fe solid solution amount is 250 ppm to 4000 ppm, and the Cu solid solution amount is 100 ppm to 500 ppm.
Appropriate heat treatment is preferably performed at a temperature of 300 ° C. or higher, preferably 600 ° C. or lower. The heat treatment time is preferably 5 hours or more, and preferably 20 hours or less. By processing under these conditions, the solid solution amount of Si, Fe, and Cu can be set to a desired value, and an aluminum alloy base plate for a lithographic printing plate having uniform pits on the electrolytic roughened surface can be obtained.

  It is desirable to set the heat treatment conditions in consideration of appropriate mechanical strength at the final desired plate thickness, and the greater the strain applied by cold rolling before heat treatment, the lower the amount of Fe dissolved, for example. It is desirable to set in consideration of what to do.

  The heat treatment can be performed in a batch heat treatment furnace. In this case, the heating rate of the coil is 100 ° C./hour or less. The holding time at a predetermined temperature varies depending on the predetermined temperature, but is long at a low temperature and short at a high temperature.

  If heat treatment is not performed under appropriate conditions during cold rolling or after final cold rolling, the size of the pits on the electrolytic roughened surface is not uniform, impairing water retention and causing ink stains and printing durability. Inferior.

<Mechanical roughening>
In the method for producing a lithographic printing plate precursor support according to the present invention, the aluminum alloy base plate described above is surface-treated. In the surface treatment, a mechanical surface roughening treatment using a rotating brush and an abrasive described below may be performed. Or you may perform the process which forms an unevenness | corrugation on the surface by transcription | transfer at the end of cold rolling.

Hereinafter, the brush grain method used as the mechanical surface roughening process will be described.
The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is carried out by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.

When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.
In the present invention, it is preferable to use a plurality of nylon brushes, specifically, 3 or more are more preferable, and 4 or more are particularly preferable. By adjusting the number of brushes, the wavelength component of the recess formed on the aluminum plate surface can be adjusted.

  The load of the drive motor that rotates the brush is preferably 1 kW plus or more, more preferably 2 kW plus or more, and particularly preferably 8 kW plus or more with respect to the load before the brush roller is pressed against the aluminum plate. By adjusting the load, the depth of the recess formed on the surface of the aluminum plate can be adjusted. The number of rotations of the brush is preferably 100 or more, and particularly preferably 200 or more.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumice stone (pumice stone), silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. Quartz sand is harder and less fragile than Pamiston, so it has excellent roughening efficiency. In addition, aluminum hydroxide is suitable when an excessive load is applied and the particles are damaged, so that it is not desired to generate deep recesses locally.
The median diameter of the abrasive is preferably 2 to 100 μm, and more preferably 20 to 60 μm, from the viewpoints of excellent surface roughening efficiency and narrowing the graining pitch. By adjusting the median diameter of the abrasive, the depth of the recess formed on the surface of the aluminum plate can be adjusted.

For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.
As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.

  As for details of an apparatus for performing a mechanical surface roughening process using a brush and an abrasive, those described in JP-A-2002-2111159 can be used by the applicant of the present application.

  In the present invention, an aluminum plate having a concavo-convex pattern formed on the surface by transfer may be used instead of mechanical roughening using a brush and an abrasive, or both roughenings may be used in combination. .

<Surface treatment>
In the method for producing a lithographic printing plate support of the present invention, a roughening treatment and an anodic oxidation treatment (in the present invention, both are referred to as a surface treatment) are performed on the above-described aluminum plate having a concavo-convex pattern formed thereon. To obtain a lithographic printing plate support.
In the roughening treatment, electrochemical roughening treatment is preferably performed twice, and etching treatment in an alkaline aqueous solution is preferably performed between them. Etching treatment in an alkaline aqueous solution (first), in an acidic aqueous solution Desmutting treatment (first), electrochemical surface roughening treatment in aqueous solution containing nitric acid or hydrochloric acid (first electrolytic treatment), etching treatment in alkaline aqueous solution (second), in acidic aqueous solution Desmutting treatment (second), electrochemical surface roughening treatment in aqueous solution containing hydrochloric acid (second electrolytic treatment), etching treatment in alkaline aqueous solution (third) and desmutting treatment in acidic aqueous solution (first 3) It is more preferable to perform the anodizing treatment in this order. It is also preferable to perform a hydrophilic treatment after the anodizing treatment.
More preferably, the mechanical surface roughening treatment is performed before the electrochemical surface roughening treatment.
In the method for producing a lithographic printing plate support of the present invention, various steps other than those described above may be included.

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

<First alkali etching treatment>
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 alkali etching treatment performed before the first electrolytic treatment is to smooth the uneven shape when mechanical roughening is performed, to form a uniform concave portion by the first electrolytic treatment, and When the mechanical surface roughening is not performed, it is performed for the purpose of removing rolling oil, dirt, natural oxide film and the like on the surface of the aluminum plate (rolled aluminum).
In the first alkali etching treatment, the etching amount is preferably 0.1 g / m ² or more, more preferably 0.5 g / m ² or more, and further preferably 1 g / m ² or more. Further, it is preferably 10 g / m ² or less, more preferably 8 g / m ² or less, and further preferably 5 g / m ² or less. When the lower limit of the etching amount is within the above range, uniform pits can be generated in the first electrolytic treatment, and further, processing unevenness can be prevented. When the upper limit of the etching amount is in the above range, the amount of the alkaline aqueous solution used is reduced, which is economically advantageous.

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

In the first alkali etching treatment, the temperature of the alkaline solution is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, and 75 ° C. or lower. Is more preferable.
In the first alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 15 seconds or shorter. preferable.

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

The apparatus for washing with a free-fall curtain-like liquid film includes a water storage tank for storing water, a water supply cylinder for supplying water to the water storage tank, and a rectification for supplying a free-fall curtain-like liquid film from the water storage tank to the aluminum plate. Part.
In this apparatus, water is supplied to the water supply tank from the water supply pipe, and when the water overflows from the water supply tank, the water is rectified by the rectification unit, and a free-falling curtain-like liquid film is supplied to the aluminum plate. When this apparatus is used, the liquid amount is preferably 10 to 100 L / min. Moreover, it is preferable that the distance L in which water exists as a free fall curtain-like liquid film between a rectification | straightening part and aluminum 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 is used, the aluminum plate can be uniformly washed with water, so that the uniformity of the treatment performed before the washing with water can be improved.
As a specific apparatus for washing with a free-fall curtain-like liquid film, for example, an apparatus described in Japanese Patent Application Laid-Open No. 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 alkali etching treatment, pickling (first desmutting treatment) is preferably performed in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing an aluminum plate into contact with an acidic solution.

Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
In the first desmut process performed after the first alkali etching process, when nitric acid electrolysis is subsequently performed as the first electrolysis process, it is preferable to use the overflow waste liquid of the electrolyte used for nitric acid electrolysis.

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

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

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

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

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

After the desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.
In the first desmutting process, when using the overflow waste liquid of the electrolyte used in the subsequent nitric acid electrolysis as the desmutting process, the surface of the aluminum plate is not subjected to the draining and washing with a nip roller after the desmutting process. It is preferable to handle the aluminum plate up to the nitric acid electrolysis step while spraying a desmut treatment solution as necessary so that it does not dry.

<First electrolytic treatment>
The first electrolytic treatment is an electrochemical surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid.
In the present invention, by performing the first electrolytic treatment and the second electrolytic treatment in this order, it is possible to form a grained shape with a highly uniform concavo-convex structure on the surface of the aluminum plate. Printing durability can be improved.
In addition, it is preferable that the average roughness Ra of the aluminum plate surface after the first electrolytic treatment is 0.2 to 1.0 μm.

(First electrolytic treatment: When performing electrochemical surface roughening in an aqueous solution containing nitric acid)
A suitable uneven structure can be formed on the surface of the aluminum plate by electrochemical surface roughening treatment (nitric acid electrolysis) in an aqueous solution containing nitric acid. In the present invention, when the aluminum plate contains a relatively large amount of Cu, a relatively large and uniform recess is formed in nitric acid electrolysis. As a result, the lithographic printing plate using the lithographic printing plate support obtained by the present invention has excellent printing durability.

An aqueous solution containing nitric acid can be used for an ordinary electrochemical surface roughening treatment using direct current or alternating current, and an aqueous solution of nitric acid having a concentration of 1 to 100 g / L, aluminum nitrate, sodium nitrate, ammonium nitrate, etc. At least one of the nitrate compounds having the nitrate ion can be added and used in the range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing nitric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L.
Specifically, a solution prepared by dissolving aluminum nitrate in an aqueous nitric acid solution having a nitric acid concentration of 5 to 15 g / L and adjusting the aluminum ion concentration to 3 to 7 g / L is preferable.

  The temperature of the aqueous solution containing nitric acid is preferably 20 ° C. or higher, and preferably 55 ° C. or lower.

  Pits having an average opening diameter of 1 to 10 μm can be formed by nitric acid electrolysis. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 10 μm are also generated.

To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably at 150C / dm ² or more, at 170C / dm ² or more more preferably, but preferably not 600C / dm ² or less, more preferably 500C / dm ² or less. The current density at this time is preferably from 20 to 100 A / dm ² at the peak value of the current in the case of using the alternating current, preferably in the case of using a DC is 20 to 100 A / dm ^2.

(First electrolytic treatment: When performing electrochemical surface roughening in an aqueous solution containing hydrochloric acid)
As the aqueous solution containing hydrochloric acid, those used for electrochemical surface roughening treatment using ordinary direct current or alternating current can be used. One or more of hydrochloric acid or nitric acid compounds having nitrate ions such as sodium nitrate and ammonium nitrate and hydrochloric acid ions such as aluminum chloride, sodium chloride and ammonium chloride can be added to 1 g / L to saturation. Moreover, the compound which forms the above-mentioned copper and a complex can also be added in the ratio of 1-200 g / L. In the aqueous solution containing hydrochloric acid, 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 aqueous hydrochloric acid is more preferably 2 to 10 g / L of hydrochloric acid, and an aluminum salt (aluminum chloride, AlCl ₃ .6H ₂ O) is added to the aqueous solution containing hydrochloric acid to make the aluminum ion concentration 3 to 7 g / L, preferably 4 Particularly preferred is an aqueous solution of ˜6 g / L. When an electrochemical surface roughening treatment is performed using such an aqueous hydrochloric acid solution, the surface shape by the surface roughening treatment becomes uniform, and a low purity aluminum rolled plate or a high purity aluminum rolled plate can be used. Further, the processing unevenness due to the roughening treatment does not occur, and it is possible to achieve both excellent printing durability and stain resistance when a lithographic printing plate is used.

  The temperature of the aqueous solution containing hydrochloric acid is preferably 20 ° C or higher, more preferably 30 ° C or higher, more preferably 55 ° C or lower, and even more preferably 50 ° C or lower.

  As the additive, apparatus, power source, current density, flow rate, and temperature in the aqueous solution containing hydrochloric acid, those used for known electrochemical surface roughening can be used. AC or DC is used as the power source used for electrochemical roughening, but AC is particularly preferable.

Since hydrochloric acid itself has a strong ability to dissolve aluminum, fine irregularities can be formed on the surface by applying a slight current. The fine irregularities have an average opening diameter of 0.01 to 0.4 μm and are uniformly generated on the entire surface of the aluminum plate.
Further, when the amount of electricity is increased (total amount of electricity (anode reaction) is 150 to 2000 C / dm ² ), pits having an average opening diameter of 0.01 to 0.4 μm on the surface and having an average opening diameter of 1 to 30 μm Produces. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is preferably 10 C / dm ² or more, and more preferably 50 C / dm ² or more. Is more preferable, and more preferably 100 C / dm ² or more. But preferably not more 2000C / dm ² or less, more preferably 600C / dm ² or less.

The current density is preferably ²⁰ to 100 A / dm ² at the peak value of the current.

  When hydrochloric acid is electrolyzed on an aluminum plate with a large amount of electricity as described above, large waviness and fine irregularities can be formed at the same time, and the large waviness is made more uniform by the second alkali etching process described later, thereby improving stain resistance. Can be made.

  The first electrolytic treatment using an aqueous solution containing nitric acid or hydrochloric acid follows, for example, the electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. be able to. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

Various electrolyzers and power sources have been proposed, including US Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP 53-32821, JP 53-32222, JP 53-32823, JP 55-122896, JP 55-13284, JP 62-127500, JP Those described in JP-A-1-52100, JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-133638, 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.

When the aluminum plate is continuously subjected to electrolytic surface roughening, the aluminum ion concentration in the alkaline solution increases, and the uneven shape of the aluminum plate formed by the first electrolytic treatment varies. Therefore, the composition management of the nitric acid electrolytic solution or hydrochloric acid electrolytic 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 a matrix of nitric acid concentration or hydrochloric acid concentration and aluminum ion concentration is prepared in advance. The liquid composition is measured by the degree, specific gravity, and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and nitric acid or hydrochloric acid and water are added so as to obtain a control target value of the liquid composition. Then, the amount of the electrolyte increased by adding nitric acid or hydrochloric acid and water is overflowed from the circulation tank, and the amount of the electrolyte is kept constant. As nitric acid to be added, 30 to 70% by mass of industrial grade can be used. As hydrochloric acid to add, the industrial thing of 30-40 mass% can be used.

As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the hydrometer, it is preferable to use a differential pressure type.
Samples taken from the electrolyte for use in measurement of the liquid composition are used for measurement after being controlled at a constant temperature (for example, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave (sin wave, sine wave), a rectangular wave, a trapezoidal wave, a triangular wave, or the like is used. Waves are preferred and trapezoidal waves are particularly preferred. In the case of the first hydrochloric acid electrolysis, a sine wave is particularly preferable in that pits having an average diameter of 1 μm or more are easily generated. The sine wave refers to that shown in FIG.
A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 0.5 to 3 msec. When TP exceeds 3 msec, especially when an aqueous solution containing nitric acid is used, it becomes susceptible to the influence of trace components in the electrolytic solution typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining. Is difficult to be performed. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

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

FIG. 2 is a side view showing an example of a radial type cell used for electrochemical roughening treatment 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. 2, 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. 2, 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. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.

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

  In addition, in the electrochemical surface roughening treatment using direct current, an electrolytic solution used for the electrochemical surface roughening treatment using normal direct current can be used. Specifically, the same electrolyte solution used for the electrochemical surface roughening treatment using the alternating current can be used.

The DC power source wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity, and a comb wave, continuous DC, commercial AC that is full-wave rectified with a thyristor, etc. can be used. Smoothed continuous direct current is preferred.
The electrochemical surface roughening treatment using direct current can be performed by any of a batch method, a semi-continuous method, and a continuous method, but is preferably performed by a continuous method.

  The apparatus used for the electrochemical surface roughening treatment using direct current applies a direct current voltage between alternately arranged anodes and cathodes, and passes through the aluminum plate at a distance from the anodes and the cathodes. If it can be made, it will not be specifically limited.

An electrode is not specifically limited, The conventionally well-known electrode used for an electrochemical roughening process can be used.
As the anode, for example, a valve metal such as titanium, tantalum, or niobium is plated or clad with a platinum group metal; the valve metal is coated with an oxide of a platinum group metal or sintered. Aluminium; stainless steel. Among these, a valve metal obtained by cladding platinum is preferable. The life of the anode can be further extended by a method such as water-cooling by passing water through the electrode.
As the cathode, for example, a metal that does not dissolve when the electrode potential is negative can be selected and used from the Boolean Bay diagram. Among these, carbon is preferable.

  The arrangement of the electrodes can be appropriately selected according to the wave structure. In addition, by changing the length of the aluminum plate between the anode and the cathode in the traveling direction, changing the passage speed of the aluminum plate, changing the flow rate of the electrolyte, the liquid temperature, the liquid composition, the current density, etc. Can be adjusted. In addition, in the case of using an apparatus in which the anode tank and the cathode tank are separated from each other, the electrolysis conditions of each treatment tank can be changed.

After the first electrolytic 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 interval between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

<Second alkali etching treatment>
The second alkaline etching process performed between the first electrolytic process and the second electrolytic process involves dissolving the smut generated by the first electrolytic process and removing the edge portion of the pit formed by the first electrolytic process. It is performed for the purpose of dissolving. As a result, the edge portion of the large pit formed by the first electrolytic treatment is melted and the surface becomes smooth, and the ink is less likely to be caught on the edge portion. it can.
Since the second alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the first electrolytic treatment becomes smooth and the ink is not easily caught, so that the stain resistance is excellent. . On the other hand, when the etching amount is 4 g / m ² or less, the unevenness generated by the first electrolytic treatment becomes large, so that the printing durability is excellent.

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

<Second desmut treatment>
After performing the second alkali etching treatment, it is preferable to perform pickling (second desmut treatment) 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.

In the second desmut treatment, nitric acid or sulfuric acid is preferably used.
In the second desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L of acid and 0.1 to 8 g / L of aluminum ions.
When using sulfuric acid, specifically, use a solution prepared by dissolving aluminum sulfate in an aqueous sulfuric acid solution having a sulfuric acid concentration of 100 to 350 g / L so that the aluminum ion concentration is 0.1 to 5 g / L. Can do. Moreover, the overflow waste liquid of the electrolyte solution used for the anodizing process mentioned later can also be used.

In the second desmut treatment, the treatment time is preferably 1 second or more, more preferably 4 seconds or more, and preferably 60 seconds or less, more preferably 20 seconds or less. .
In the second desmut treatment, the temperature of the acid aqueous solution is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, preferably 60 ° C. or lower. More preferred.

<Second electrolytic treatment (second hydrochloric acid electrolysis)>
The second electrolytic treatment is an electrochemical surface roughening treatment using alternating current or direct current in an aqueous solution containing hydrochloric acid. In the present invention, only the first electrolytic treatment described above may be used, but by combining this second electrolytic treatment, a more complicated uneven structure can be formed on the surface of the aluminum plate, and thus the printing durability is excellent. Can be

The second hydrochloric acid electrolysis performed after the first electrolytic treatment is basically the same as described in the first hydrochloric acid electrolysis.
The total amount of electricity that the aluminum plate participates in the anodic reaction by electrochemical surface roughening in an aqueous solution containing hydrochloric acid in the second hydrochloric acid electrolysis is 10 to 10 when the electrochemical surface roughening treatment is completed. 10 to 100 C / dm ² is preferable and 50 to 80 C / dm ² is particularly preferable so that the rough surface formed by the first electrolytic treatment can be selected from a range of 200 C / dm ² .

<First alkali etching treatment-first nitric acid electrolysis (roughening) treatment-second alkali etching treatment-second hydrochloric acid electrolysis (roughening) treatment>
When performing the above treatment in combination, the first electrochemical surface roughening treatment is carried out in an electrolytic solution containing nitric acid at a total electricity of 65 to 500 C / dm ² in the anode reaction, and 0.1 g / m ² After the above Al is chemically dissolved, the second electrolytic surface roughening treatment is performed in an electrolytic solution containing hydrochloric acid at a total electric quantity of 25 to 100 C / dm ² in the anode reaction, and then 0.03 g / m ^2. It is preferable to chemically dissolve the above Al. If the aluminum alloy base plate of the present invention is roughened with this combination, a lithographic printing plate support excellent in stain resistance and printing durability can be obtained.

<Third alkali etching treatment>
The third alkali etching treatment performed after the second electrolytic treatment is performed for the purpose of dissolving the smut generated by the second electrolytic treatment and dissolving the edge portion of the pit formed by the second electrolytic treatment. Is called. Since the third alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the third alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, is 0.3 g / m ² or less Of 0.25 g / m ² or less is more preferable. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the second hydrochloric acid electrolysis becomes smooth and the ink is not easily caught, so that the stain resistance is excellent. . On the other hand, when the etching amount is 0.3 g / m ² or less, the unevenness generated by the first hydrochloric acid electrolysis and the second hydrochloric acid electrolysis becomes large, so that the printing durability is excellent.

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

In the third alkali etching treatment, the temperature of the alkaline solution is preferably 25 ° C or higher, more preferably 30 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.
In the third alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

<Third desmut treatment>
After the third alkali etching treatment, it is preferable to perform pickling (third desmut treatment) in order to remove dirt (smut) remaining on the surface. Since the third desmut process is basically the same as the first desmut process, only the differences will be described below.
In the third desmutting treatment, it is preferable to use an acidic solution containing 5 to 400 g / L acid and 0.5 to 8 g / L aluminum ions. When sulfuric acid is used, specifically, a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L to adjust the aluminum ion concentration to 1 to 5 g / L is preferable.

In the third desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, more preferably 60 seconds or shorter, and more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of liquid as the electrolyte used in the subsequent anodizing process is used as the desmut process liquid, the draining with a nip roller and the water washing process can be omitted after the desmut process.

<Anodizing treatment>
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 anodized film can be formed by energizing an aluminum plate as an anode. 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. ˜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, more preferably 30 to 50.

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 the anodizing treatment, so that current is concentrated on a part of the aluminum plate and so-called “burning” (part where the film becomes thicker than the surroundings) does not occur. 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 such 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 treatment is continuously performed, it is preferable that the anodizing process is performed by a liquid power feeding method in which power is supplied to the aluminum plate through an electrolytic solution.
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. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate is likely to be scratched. On the other hand, if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable 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.

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. 3 is preferably used. FIG. 3 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. 3, in order to energize the aluminum plate 416 via the electrolytic solution, a power feeding tank 412 is provided on the upstream side in the traveling direction of the aluminum plate 416, and an anodizing treatment 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 continuously 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 on 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 an electrode divided into a plurality of pieces in the traveling direction of the aluminum plate 416 in order to make it easy for hydrogen gas generated by the anode reaction to escape 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 that does not accumulate an electrolyte 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. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, even if the sealing treatment is performed by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, and the like. Good.

<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 fluorinated zirconate 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 subbing layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

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

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

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

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

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, a sulfo group-containing vinyl polymerizable compound 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 more, more preferably 2 seconds or more, preferably 20 seconds or less, and more preferably 15 seconds.

<Management of liquid composition>
In the present invention, it is preferable to manage the composition of various processing solutions used for the surface treatment described above by the method described in JP-A-2001-121837. Prepare a large number of treatment liquid samples of various concentrations in advance, measure the ultrasonic wave propagation speed at each of the two liquid temperatures, create a matrix-like data table, It is preferable to measure the propagation speed of the light in real time and control the concentration based on the measurement. In particular, in the desmutting treatment, when an electrolytic solution having a sulfuric acid concentration of 250 g / L or more is used, it is preferable to control the concentration by the method described above.
In addition, it is preferable that each electrolyte solution used for an electrolytic roughening process and an anodic oxidation process is 100 ppm or less of Cu concentration. If the Cu concentration is too high, Cu is deposited on the aluminum plate when the line is stopped, and Cu deposited when the line is operated again may be transferred to a pass roll, which may cause processing unevenness.

[Lithographic printing plate precursor]
The lithographic printing plate support obtained by the present invention can be provided with an image recording layer to form the lithographic printing plate precursor of the present invention. A photosensitive composition is used for the image recording layer.
Examples of the photosensitive composition suitably used in the present invention include a thermal positive photosensitive composition containing an alkali-soluble polymer compound and a photothermal conversion substance (hereinafter, this composition and an image recording layer using the same). ), A thermal negative photosensitive composition containing a curable compound and a photothermal conversion substance (hereinafter also referred to as “thermal negative type”), a photopolymerizable photosensitive composition (hereinafter referred to as “thermal positive type”). , Also referred to as “photopolymer type”), negative photosensitive composition containing diazo resin or photocrosslinking resin (hereinafter also referred to as “conventional negative type”), and positive photosensitive composition containing quinonediazide compound. Product (hereinafter also referred to as “conventional positive type”), a photosensitive composition that does not require a special development step (hereinafter referred to as “the conventional positive type”). As the referred to as "non-treatment type".), And the like. 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, the polymer compound described in JP-A No. 2001-305722 (particularly [0023] to [0042]), and the 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 may contain a dissolution inhibitor. As the dissolution inhibitor, for example, dissolution inhibitors described in JP-A-2001-305722, [0053] to [0055] are preferably exemplified.
In addition, in the thermal positive type photosensitive composition, as a additive, a sensitivity modifier, a printing agent for obtaining a visible image immediately after heating by exposure, a compound such as a dye as an image colorant, a coating property In addition, it is preferable to include a surfactant for improving the processing stability. For these, compounds described in JP-A-2001-305722, [0056] to [0060] are preferable.
The photosensitive composition described in detail in Japanese Patent Application Laid-Open No. 2001-305722 is also preferably used in other respects.

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 in 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 JP-A-2002-3233769, [0062] to [0085] 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 light-to-heat conversion substance is converted into heat, the radical generator is decomposed by this heat to generate radicals, and the radical polymerizable compound is polymerized in a chain by the generated radicals and cured. .

As a photothermal conversion substance, the photothermal conversion substance used for the thermal positive type mentioned above is mentioned, for example. Specific examples of particularly preferred cyanine dyes include those described in JP-A-2001-133969, [0017] to [0019].
Preferred 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 radical 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. Preferred 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.

  In the thermal negative photosensitive composition, an additive described in JP-A-2001-133969, [0061] to [0068] (for example, a surfactant for improving coatability) is contained. 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 cross-linking layer comprises a photothermal conversion substance, a thermal acid generator, a compound that cross-links with an acid that is a curable compound (cross-linking agent), and an alkali-soluble polymer compound that can react with the cross-linking agent in the presence of an acid. contains. In the acid cross-linking layer, infrared light absorbed by the photothermal conversion substance is converted into heat, the heat 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 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-type photosensitive composition contains a diazo resin or a photocrosslinking resin. Among them, preferred is a photosensitive composition containing a diazo resin and an alkali-soluble or swellable polymer compound (binder).
Examples of the diazo resin include condensates of aromatic diazonium salts and active carbonyl group-containing compounds such as formaldehyde; condensates of p-diazophenylamines and formaldehyde with hexafluorophosphate or tetrafluoroborate. Organic solvent-soluble diazo resin inorganic salts which are reaction products 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 additives, the bake-out 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 converted into a lithographic printing plate by various treatment methods according to the image recording layer.
Examples of the actinic ray light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include a helium-neon laser (He-Ne laser), an argon laser, a krypton laser, a helium-cadmium laser, a KrF excimer laser, a semiconductor laser, a YAG laser, and a YAG-SHG laser.

After the above exposure, if the image recording layer is any of thermal positive type, thermal negative type, conventional negative type, conventional positive type, and photopolymer type, after exposure, it is developed using a developer to obtain a lithographic printing plate. It is preferable to obtain.
The developer is preferably an alkaline developer, and more preferably an alkaline aqueous solution substantially free of an organic solvent.
Moreover, the developing solution which does not contain alkali metal silicate substantially is also preferable. As a method of developing using a developer substantially not containing an alkali metal silicate, a method described in detail in JP-A No. 11-109637 can be used.
A developer containing an alkali metal silicate can also be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Examples 1-12, Comparative Examples 1-3)

[1] [Relationship between amount of alloy element solid solution and electrolytic rough surface]
The aluminum materials having the compositions shown in Table 1 were subjected to heat treatments shown in Tables 2, 3, and 4 to adjust the solid solution amounts of Fe, Si, and Cu, respectively. An alloy base plate was manufactured, and the following surface treatment was performed to obtain an aluminum support for a lithographic printing plate, and the uniformity of the electrolytic rough surface was evaluated.
Table 1 shows the chemical compositions of various alloys of the present invention and comparative alloys used in this test.

＜表面処理：電解粗面化条件Ｉで電解粗面化する＞
（ａ）アルカリエッチング
アルミニウム板に、カセイソーダ濃度２５質量％、アルミニウムイオン濃度１００ｇ／Ｌ、温度６０℃の水溶液をスプレー管から吹き付けて、エッチング処理を行った。アルミニウム板の後に電気化学的粗面化処理を施す面のエッチング量は、５ｇ／ｍ² であった。
（ｂ）デスマット処理
温度３５℃の１質量％の硝酸水溶液をスプレー管から５秒間吹き付けて、デスマット処理を行った。
（ｃ）電解粗面化条件Ｉでの電解粗面化処理
硝酸水溶液中での交流を用いた電気化学的粗面化処理（第一電解処理）
その後、１質量％硝酸水溶液に硝酸アルミニウムを溶解させてアルミニウムイオン濃度を４．５ｇ／Ｌとした電解液（液温５０℃）を用い、６０Ｈｚの交流電圧を用いて連続的に電気化学的粗面化処理を行った。交流電源波形は図１に示した波形であり、電流値がゼロからピークに達するまでの時間ＴＰが０．８ｍｓｅｃ、ｄｕｔｙ比（ｔａ／Ｔ、１サイクルに占めるアノード反応時間の割合）０．５であった。カーボン電極を対極として用いた。補助アノードにはフェライトを用いた。電解槽は図２に示すものを２槽使用した。
電気化学的粗面化処理において、交流のピーク時におけるアルミニウム板のアノード反応時の電流密度は、６０Ａ／ｄｍ² であった。アルミニウム板のアノード反応時の電気量の総和とカソード反応時の電気量の総和との比は０．９５であった。電気量はアルミニウム板のアノード時の電気量の総和で１９０Ｃ／ｄｍ² であった。補助陽極には電源から流れる電流の５％を分流させた。アルミニウム板と電解液の相対速度は、電解槽内の平均で１．５ｍ／ｓｅｃであった。
（ｄ）アルカリエッチング
アルミニウム板に、カセイソーダ濃度５質量％、アルミニウムイオン濃度５ｇ／Ｌ、温度３５℃の水溶液をスプレー管から吹き付けて、エッチング処理を行った。アルミニウム板の電気化学的粗面化処理を施した面のエッチング量は、０．１ｇ／ｍ² であった。
（ｅ）デスマット処理
水溶液としては、硫酸濃度３００ｇ／Ｌ、アルミニウムイオン濃度５ｇ／Ｌ、液温３５℃を用いて、スプレー管から５秒間吹き付けて、デスマット処理を行った。
（ｆ）全ての処理工程の間には水洗を差し挟んだ。

<Surface treatment: Electrolytic roughening under electrolytic roughening condition I>
(A) Alkaline etching An aqueous solution having a caustic soda concentration of 25% by mass, an aluminum ion concentration of 100 g / L, and a temperature of 60 ° C. was sprayed onto the aluminum plate from a spray tube to perform an etching process. The etching amount of the surface subjected to the electrochemical roughening treatment after the aluminum plate was 5 g / m ² .
(B) Desmut treatment A 1% by mass nitric acid aqueous solution having a temperature of 35 ° C was sprayed from the spray tube for 5 seconds to perform desmut treatment.
(C) Electrolytic roughening treatment under electrolytic roughening condition I Electrochemical roughening treatment using alternating current in an aqueous nitric acid solution (first electrolytic treatment)
Thereafter, an electrolytic solution (solution temperature: 50 ° C.) in which aluminum nitrate is dissolved in a 1% by mass nitric acid aqueous solution to have an aluminum ion concentration of 4.5 g / L is continuously electrochemically roughened using an alternating voltage of 60 Hz. Surface treatment was performed. The AC power supply waveform is the waveform shown in FIG. 1. The time TP until the current value reaches a peak from zero is 0.8 msec, the duty ratio (ta / T, the ratio of the anode reaction time in one cycle) 0.5 Met. A carbon electrode was used as the counter electrode. Ferrite was used for the auxiliary anode. Two electrolytic cells shown in FIG. 2 were used.
In the electrochemical surface roughening treatment, the current density during the anode reaction of the aluminum plate at the peak of alternating current was 60 A / dm ² . The ratio of the total amount of electricity during the anode reaction of the aluminum plate to the total amount of electricity during the cathode reaction was 0.95. The amount of electricity was 190 C / dm ² in terms of the total amount of electricity when the aluminum plate was anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. The relative speed of the aluminum plate and the electrolytic solution was 1.5 m / sec on average in the electrolytic cell.
(D) Alkaline etching An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 5 mass%, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. from an spray tube to carry out an etching treatment. The etching amount of the aluminum plate subjected to the electrochemical surface roughening treatment was 0.1 g / m ² .
(E) Desmutting treatment As an aqueous solution, desmutting treatment was performed by spraying from a spray tube for 5 seconds using a sulfuric acid concentration of 300 g / L, an aluminum ion concentration of 5 g / L, and a liquid temperature of 35 ° C.
(F) Water washing was inserted between all the treatment steps.

About the obtained support body, the solid solution amount and the uniformity of the electrolytic surface roughening were measured under the following conditions, and the results are shown in Tables 2, 3 and 4.
<Evaluation of uniformity of electrolytic rough surface>
The surface after the electrolytic surface roughening treatment was observed with a scanning electron microscope (SEM: JEOL 5500) (magnification 2000 times), and the uniformity of graining was evaluated. The results are shown in Tables 2-6 and 8.
(Double-circle): A round pit is 90% or more of the whole.
◯: Round pits are 50% or more and less than 90% of the whole.
(Triangle | delta): A round pit is 10% or more and less than 50% of the whole.
X: A round pit is less than 10% of the whole.

<Measurement of solid solution amount and uniformity of electrolytic rough surface>
Regarding the alloy base plate of the present invention obtained as described above and the alloy base plate of the comparative example, the relationship between the solid solution amount of the alloy element and the uniformity of the electrolytic rough surface was compared.

<Measurement of solid solution amount of Fe, Si, Cu>
It was measured by the phenol dissolution extraction method. After dissolving the sample with hot phenol, benzyl alcohol was added. Filtration was performed using a polytetrafluoroethylene filter to remove the intermetallic compound residue. After dilution with benzyl alcohol, Fe, Si, and Cu contained in the solution were extracted and quantified by standard addition ICP emission spectrometry.

<Surface treatment: electrolytic surface roughening treatment under electrolytic surface roughening condition II>
The base plate obtained in the same manner was subjected to brush graining in a suspension of Pamistone (particle diameter 30 μm (median diameter)) / water (specific gravity 1.5), and then (a) alkaline etching (aluminum dissolution amount of 0.1%). 3g / m ² ), (b) Desmut treatment (1% nitric acid solution, 30 ° C., 10 seconds), and using a power source with an electrolytic waveform in which the polarity is alternately converted, the amount of electricity at the time of anode in 1% nitric acid Was subjected to electrolytic surface-roughening treatment so as to be 190 C / dm ² . After washing in sulfuric acid (sulfuric acid concentration 300 g / L, 60 ° C., 3 seconds), the uniformity of the electrolytic surface roughening was similarly evaluated.
<Evaluation of uniformity of electrolytic rough surface>
The uniformity of the electrolytic surface roughening was evaluated by the same method as that of the support obtained by the surface treatment when the electrolytic surface roughening was performed under the electrolytic surface roughening condition I described above. The results are shown in Tables 2-4. In the table, condition I indicates a case where surface treatment including electrolytic surface roughening treatment I is performed, and condition II indicates a case where surface treatment including electrolytic surface roughening treatment condition II is performed.

(Examples 13-17, Comparative Examples 4-5)
[2] [Relationship between resistivity and electrolytic rough surface]
The aluminum material of Al-10 shown in Table 1 is subjected to the heat treatment shown in Table 5 to adjust the amount of Si dissolved, and the surface treatment including the electrolytic surface roughening treatment I is performed. An aluminum support for a printing plate was obtained, and the uniformity of the specific resistance and electrolytic rough surface was evaluated and shown in Table 5.
(3) Specific resistance measurement conditions The specific resistance of the surface-treated lithographic printing plate aluminum support specimen was measured under liquid nitrogen conditions.

(Example 18, Comparative Example 6)
[3] [Solution amount of alloy element and visibility of grain pattern on back side]
The aluminum material of Al-1 shown in Table 1 is subjected to the heat treatment shown in Table 6 to adjust the solid solution amount of Si, and the following surface treatment is performed to obtain an aluminum support for a lithographic printing plate. Then, the solid solution amount of Si, the uniformity of the electrolytic rough surface, and the visibility of the grain pattern on the back surface were evaluated and are shown in Table 6.
<Surface treatment>
The surface treatment including the electrolytic surface-roughening treatment II was performed except that (g) the back surface was subjected to alkaline etching under the following conditions between (a) alkali etching and (b) desmut treatment.
(G) Alkali etching of the back surface An aqueous solution having a caustic soda concentration of 25% by mass, 100 g / L, and a temperature of 60 ° C. was sprayed from the spray tube onto the back surface of the aluminum plate to perform an etching treatment. The etching amount of the surface was 3 g / m ² .
(4) Evaluation of the visibility of the grain-like pattern on the back side ○: Good (the pattern is visible)
Δ: thin (acceptable)
×: None (the pattern cannot be seen)

(Examples 19-24, Comparative Examples 7-12)
[4] [Evaluation of solid solution amount of alloying elements, electrolytic surface roughening conditions and printability]
The aluminum material of Al-11 shown in Table 1 was subjected to heat treatment, the solid solution amount was adjusted and measured, and the following surface treatment was performed to obtain an aluminum support for a lithographic printing plate. The thermal type photosensitive material was applied under the following conditions to expose, develop and print as a lithographic printing plate precursor, and the printability (stain resistance) was evaluated. The results are shown in Table 7.
<Surface treatment>
(A) Alkaline etching An aqueous solution having a caustic soda concentration of 25% by mass, an aluminum ion concentration of 100 g / L, and a temperature of 60 ° C. was sprayed onto the aluminum plate from a spray tube to perform an etching process. The etching amount of the surface subjected to the electrochemical roughening treatment after the aluminum plate was 6 g / m ² .
(B) Desmut treatment A 1% by mass nitric acid aqueous solution having a temperature of 35 ° C was sprayed from the spray tube for 5 seconds to perform desmut treatment.
(C) Electrolytic surface roughening treatment Using an electrolytic solution (liquid temperature 50 ° C.) in which aluminum nitrate is dissolved in a 1% by mass nitric acid aqueous solution to have an aluminum ion concentration of 4.5 g / L, continuous using an alternating voltage of 60 Hz. An electrochemical surface roughening treatment was performed. The AC power supply waveform is the waveform shown in FIG. 1, and the time TP until the current value reaches the peak from zero was 0.8 msec, and the duty ratio (ta / T) was 0.5. A carbon electrode was used as the counter electrode. Ferrite was used for the auxiliary anode. Two electrolytic cells shown in FIG. 2 were used.
In the electrochemical surface roughening treatment, the current density during the anode reaction of the aluminum plate at the alternating current peak was changed as shown in Table 7. The ratio of the total amount of electricity during the anode reaction of the aluminum plate to the total amount of electricity during the cathode reaction was 0.95. The amount of electricity was 250 C / dm ^{2 as} the total amount of electricity when the aluminum plate was anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. The relative speed of the aluminum plate and the electrolytic solution was 1.5 m / sec on average in the electrolytic cell.
(D) Alkaline etching An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 5 mass%, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. from an spray tube to carry out an etching treatment. The etching amount of the surface of the aluminum plate subjected to the electrochemical surface roughening treatment was changed as shown in Table 7.
(E) Desmut treatment As the aqueous solution, desmut treatment was performed by spraying from a spray tube for 5 seconds using a sulfuric acid concentration of 15% by mass, an aluminum ion concentration of 5 g / L, and a liquid temperature of 35 ° C.
(H) Anodizing treatment Anodizing treatment was performed using the anodizing treatment apparatus shown in FIG.
As the electrolytic solution, an electrolytic solution (temperature 33 ° C.) in which aluminum sulfate was dissolved in a 170 g / L sulfuric acid aqueous solution to make the aluminum ion concentration 5 g / L was used. The anodizing treatment was performed so that the average current density during the anodic reaction of the aluminum plate (about 16 seconds) was 15 A / dm ² , and the final oxide film amount was 2.4 g / m ² . The time for the aluminum plate to participate in the anodic reaction was 16 seconds.
(I) Silicate treatment (hydrophilization treatment)
The aluminum plate was immersed in a 1% by weight aqueous solution of sodium silicate No. 3 (liquid temperature 20 ° C.) for 10 seconds. The amount of Si on the surface of the aluminum plate measured with a fluorescent X-ray analyzer was 3.5 mg / m ² .
(F) Water washing was inserted between all the treatment steps.

<Manufacture of lithographic printing plate precursor>
Each flat support obtained above was provided with the following thermal positive type image recording layer to obtain a lithographic printing plate precursor. Before providing the image recording layer, the following undercoat layer was provided.

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

得られた平版印刷版原版をＣｒｅｏ社製ＴｒｅｎｄＳｅｔｔｅｒを用いてドラム回転速度１５０ｒｐｍ、ビーム強度１０Ｗで画像状に描き込みを行った。
その後、下記組成のアルカリ現像液を仕込んだ富士写真フイルム（株）製ＰＳプロセッサー９４０Ｈを用い、液温を３０℃に保ち、現像時間２０秒で現像し、平版印刷版を得た。

The resulting 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 alkali developer having the following composition, the solution was maintained at 30 ° C. and developed for 20 seconds to obtain a lithographic printing plate.

<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 mass%
・ Water 96.15% by mass
(5) Evaluation of printability (stain resistance) Using the lithographic printing plate obtained above, printing is performed with a DIC-GEOS (s) red ink on a Mitsubishi diamond F2 printer (manufactured by Mitsubishi Heavy Industries). The blanket stains after printing 10,000 sheets were visually evaluated.
The results are shown in Table 7. Evaluation was as follows.
A: The blanket is not dirty B: The blanket is almost unclean C: The blanket is slightly dirty D: The blanket is dirty but within an acceptable range E: The blanket is dirty and the printed matter is clear F: The blanket is very dirty G: The blanket is very dirty

(Examples 25 to 28)
[5] [Evaluation of solid solution amount of alloy element, electrolytic surface roughening condition and printability]
The aluminum materials of Al-12 shown in Table 1 were each heat-treated, the amount of solid solution was adjusted and measured, and the following surface treatment was performed to obtain an aluminum support for a lithographic printing plate. The same thermal type photosensitive material as that for evaluation of printability was applied under the same conditions, and a lithographic printing plate precursor was similarly exposed, developed, printed, evaluated for printability (stain resistance), and the results are shown in Table 8. Indicated.

<Surface treatment>
(C) Surface treatments (a) to (f) were performed in the same manner as in the test [4] except that the electrolytic surface-roughening treatment and (d) alkali etching were performed under the following conditions.
(C) Electrolytic roughening treatment As shown in Table 8, the current density is 20 A / dm ² , and the electrolytic solution is an aqueous solution of 1% by mass nitric acid or an aqueous solution of 1% by mass hydrochloric acid as shown in Table 8. The electrolytic surface-roughening treatment described in (4) of [4] was performed except that a trapezoidal wave or a sine wave was used.
(D) Alkaline etching An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 5 mass%, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. from an spray tube to carry out an etching treatment. The etching amount of the surface of the aluminum plate subjected to the electrochemical roughening treatment was 0.2 g / m ² .

(Examples 29 to 31)
[6] [Evaluation of solid solution amount of alloy element, electrolytic surface roughening condition and printability]
The aluminum material of Al-12 shown in Table 1 is heat-treated to adjust the amount of solid solution, and the following surface treatment is performed to obtain an aluminum support for a lithographic printing plate. The same thermal type light-sensitive material as in the evaluation was applied under the same conditions to obtain a lithographic printing plate precursor, which was similarly exposed, developed, printed, evaluated for printability (stain resistance), and the results are shown in Table 9.

<Surface treatment>
First, the same test as in the above [4], except that (j) brush grain treatment was performed under the following conditions, and (c) electrolytic surface roughening treatment and (d) alkali etching were performed under the following conditions. Surface treatment was performed.
(J) Brush Grain Treatment A suspension in which a pumiston having a specific gravity of 1.13 (median diameter of 30 μm) is suspended in water is used as a polishing slurry liquid, and a laminated brush roll having a bristle diameter of 0.3 mm is used. Mechanical roughening was performed so that Ra after etching was 0.45 μm.
(C) Electrolytic roughening treatment In Examples 29 and 30, as shown in Table 9, (c) only the first electrolytic roughening was performed, and the next step (d) was alkali-etched.
In Example 31, as shown in Table 9, (c) -2 second electrolytic surface roughening was performed via alkali etching after (c) first electrolytic surface roughening, followed by further step (d) alkali etching.
(6) Evaluation of printing durability The obtained lithographic printing plate precursor was a lithographic printing plate precursor similar to the test of [4]. Thereafter, the image was drawn in the same manner.
Thereafter, development was performed under the same conditions with a similar processor charged with the same developer to obtain a lithographic printing plate.

  The resulting 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 number of printing durability was almost the same in Example 29 and Example 30 and was 50,000. The results are shown in Table 9.

It is a graph which shows an example of the alternating waveform current waveform figure used for the 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. It is a graph which shows an example of the sine waveform figure used for the electrochemical roughening 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 410 Anode Oxidation treatment apparatus 412 Power supply tank 413 Intermediate tank 414 Anodization treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Anode 422, 428 Pass roller 424 Nip roller 430 Cathode 434 DC power supply 436, 438 Liquid supply nozzle 440 Screening plate 442 Drain outlet

Claims (11)

  A continuously cast and rolled plate made of an aluminum alloy, containing 0.20 to 0.80 mass% Fe, the balance being made of aluminum, a grain refinement element, and an unavoidable impurity element, A lithographic printing plate characterized in that the Si content is 0.02 to 0.30 mass%, the Cu content is 0.05 mass% or less, and the solid solution content of Si is 150 ppm to 1500 ppm. Aluminum alloy base plate.   The aluminum alloy base plate for a lithographic printing plate according to claim 1, wherein the solid solution amount of Fe is 250 ppm or more and 4000 ppm or less.   The aluminum alloy base plate for a lithographic printing plate according to claim 1 or 2, wherein the solid solution amount of Cu is 100 ppm or more and 500 ppm or less.   The aluminum alloy base plate for a lithographic printing plate according to any one of claims 1 to 3, wherein the specific resistance measured at a liquid nitrogen temperature is 6.5 to 3.5 µΩmm.   A support for a lithographic printing plate, wherein the aluminum alloy base plate for a lithographic printing plate according to any one of claims 1 to 4 is subjected to a roughening treatment including an electrochemical roughening treatment. After the surface roughening treatment including the electrochemical surface roughening treatment is performed at an electric current density of 5 A / dm ² or more and electrochemical surface roughening treatment, 0.1 g / m ² or more of Al is chemically treated. The lithographic printing plate support according to claim 5, which dissolves.   The lithographic printing plate support according to claim 6, wherein the electrochemical surface roughening treatment is a treatment using an alternating current having a trapezoidal waveform in an electrolytic solution containing nitric acid.   The lithographic printing plate support according to claim 6, wherein the electrochemical surface roughening treatment is treatment using an alternating current having a sinusoidal waveform in an electrolyte containing hydrochloric acid. The surface roughening treatment including the electrochemical surface roughening treatment is performed as a first electrochemical surface roughening treatment in an electrolytic solution containing nitric acid at a total electric quantity of 65 to 500 C / dm ² in an anodic reaction. Then, after chemically dissolving 0.1 g / m ² or more of Al, the second electrolytic surface roughening treatment is performed in an electrolytic solution containing hydrochloric acid at a total electricity of 25 to 100 C / dm ² in the anode reaction, The lithographic printing plate support according to claim 5, wherein 0.03 g / m ² or more of Al is chemically dissolved thereafter.   A lithographic printing plate precursor having a recording layer on one surface of the lithographic printing plate support according to any one of claims 5 to 9. A lithographic printing plate precursor having a recording layer on one side of the lithographic printing plate support according to any one of claims 5 to 9, and having a wood grain pattern or stripe pattern on the other side.

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