JP5266177B2 - Planographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original lithographic printing plate capable of obtaining a lithographic printing plate excellent in resistance to plate wear by suppressing the occurrence of local remaining film and development scum. <P>SOLUTION: The original lithographic printing plate has an image recording layer which contains an alkali-soluble resin and an infrared ray absorber and in which the alkali-solubility of an exposure part increases after infrared ray exposure, on a support, wherein the support is formed by using an aluminum alloy plate wherein the density, on the surface, of an inter-metallic compound having a circle-equivalent diameter of 0.2 &mu;m or more is 35,000 pieces/mm<SP>2</SP>or more. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a lithographic printing plate precursor.

The development of lasers in recent years has been remarkable, and in particular, solid-state lasers, semiconductor lasers, gas lasers, and the like that emit ultraviolet light, visible light, or infrared light having a wavelength of 300 to 1200 nm can be easily obtained with small outputs. It has become.
These lasers are extremely useful as recording light sources when directly making a plate from digital data such as a computer in lithographic printing.

Among these lasers, as a positive recording material compatible with an infrared laser having a photosensitive wavelength of 760 nm or more, a lithographic plate comprising an alkaline aqueous solution-soluble binder resin, an infrared absorbing dye that absorbs light and generates heat, and the like as essential components Printing plate materials are known (see, for example, Patent Documents 1 to 4).
When an infrared laser is exposed to such a positive recording material compatible with an infrared laser, the solubility of the binder resin is substantially reduced in the non-exposed area (image area) due to the interaction between the infrared absorbing dye and the binder resin. In the exposed area (non-image area), since the infrared absorbing dye or the like absorbs light and generates heat, the interaction between the infrared absorbing dye and the binder resin becomes weak. As a result, at the time of development, only the exposed portion is dissolved and removed in the alkaline developer, and a lithographic printing plate is formed.

However, in such a positive-type recording material compatible with an infrared laser, the exposed portion (non-image portion) is not dissolved in the alkaline developer, but has a pot-like residual film (hereinafter referred to as “pot-like residual film”). There was a problem that occurred and caused printing stains.
In development using an automatic developing machine, the exposed lithographic printing plate precursor is repeatedly immersed in a developing bath containing an alkali developer, and many lithographic printing plate precursors are passed through the automatic developing solution. Then, an aluminum residue (hereinafter referred to as “development residue”) is generated in the developing bath, which may adhere to the non-image area of the lithographic printing plate and cause stains.

JP 11-44956 A JP 2002-55446 A JP 2002-62660 A JP 2002-214767 A

  Accordingly, an object of the present invention is to provide a lithographic printing plate precursor capable of suppressing the generation of pot-like residual film and development residue and obtaining a lithographic printing plate excellent in stain resistance.

The present inventor has conducted intensive studies to achieve the above object, the support circle corresponding to the surface diameter is formed using an aluminum alloy plate having more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ² As a result, it was found that a lithographic printing plate excellent in stain resistance can be obtained by suppressing the occurrence of pot-like residual film and development residue, and the present invention was completed.
That is, the present invention provides the following (1) to (10).

(1) A lithographic printing plate precursor comprising an alkali-soluble resin and an infrared absorber on a support, and having an image recording layer in which the alkali solubility of an exposed portion increases after infrared exposure,
Said support is a circle corresponding to the surface diameter is formed using an aluminum alloy plate having more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ^2,
The aluminum of the intermetallic compound having the alloy plate, circle equivalent diameter intermetallic compounds than 1.0μm is 2500 / mm ² or less der Ru lithographic printing plate precursor.

(2) The lithographic printing plate precursor as described in (1) above, wherein the support has 40000 pieces / mm ² or more of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface .

  (3) The lithographic printing plate precursor as described in (1) or (2) above, wherein the alkali-soluble resin is a phenol resin.

  (4) The lithographic printing plate precursor as described in (3) above, wherein the phenol resin is a novolac resin.

  (5) The lithographic printing plate precursor as described in any one of (1) to (4) above, wherein the aluminum alloy plate is produced by a continuous casting method.

  (6) The aluminum alloy plate is obtained by continuous casting in which a molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. The lithographic printing plate precursor as described in (5) above.

  (7) The said support body is any one of said (1)-(6) which is a support body obtained by performing the roughening process containing an electrochemical roughening process on the surface of the said aluminum alloy plate. Lithographic printing plate precursor.

  (8) The lithographic printing plate precursor as described in (7) above, wherein the roughening treatment is a roughening treatment comprising an anodizing treatment after the electrochemical roughening treatment.

  (9) The lithographic printing plate precursor as described in (8) above, wherein the anodizing treatment is anodizing treatment using an electrolytic solution containing sulfuric acid or phosphoric acid.

(10) An image recording step for recording an image by imagewise exposure on the lithographic printing plate precursor as described in any of (1) to (9) above;
A method for making a lithographic printing plate, comprising: a development step in which the lithographic printing plate precursor on which an image is recorded is subjected to a development treatment using a developer having a pH of 9 or more to obtain a lithographic printing plate.

  As will be described below, according to the present invention, it is possible to provide a lithographic printing plate precursor capable of suppressing the generation of pot-like residual film and development residue and obtaining a lithographic printing plate having excellent stain resistance. .

Here, although the reason which can suppress generation | occurrence | production of a pot-like residual film | membrane is not clear, this inventor thinks as follows. In other words, the occurrence of a pot-like residual film occurs when the image recording layer enters a relatively large recess that can be formed when the surface of the aluminum alloy plate is roughened, and it does not dissolve during the development process. There is a cause in remaining. And when this inventor has a comparatively large intermetallic compound (for example, an equivalent circle diameter is 1.0 micrometer or more) on the surface of an aluminum alloy plate, roughening processing (especially, It has been clarified that a relatively large recess is generated during the alkali etching treatment. Therefore, by using the aluminum alloy plate circle surface equivalent diameter have more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ^2, there is less of a relatively large intermetallic compounds, resulting rough surface It is considered that large recesses are not formed even by the crystallization treatment, and the generation of a pot-like residual film is suppressed.

In addition, regarding the generation of development residue, the present inventor has found that a relatively large intermetallic compound exists on the surface of the non-image area of the lithographic printing plate precursor, that is, the surface of the aluminum alloy plate (support), which is the development bath. It became clear that it becomes the nucleus (starting point) of the residue. Therefore, by using the aluminum alloy plate circle surface equivalent diameter have more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ^2, there is less of a relatively large intermetallic compounds, resulting, developing bath It is thought that the generation of nuclei of scum in the

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. 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 the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates of this invention.

Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
[Aluminum alloy sheet (rolled aluminum)]
The support used for the lithographic printing plate precursor of the present invention (hereinafter also referred to as “the support for a lithographic printing plate of the present invention”) includes an aluminum alloy plate described below (hereinafter “the aluminum alloy plate of the present invention”). Is also used.). The essential alloy components in the aluminum alloy are Al, Fe and Si, and may contain copper (Cu) as an optional component.

  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 invention, the Si content is preferably 0.03 to 0.20 mass%, more preferably 0.04 to 0.18 mass%, and 0.05 to 0.15 mass%. More preferably.
When the Si content is within this range, the necessary amount of Si solid solution is ensured, and even when the anodizing treatment is performed after the electrolytic surface-roughening treatment, it is difficult for defects to occur in the anodized film. Thus, the stain resistance as a lithographic printing plate is also improved.

In the present invention, the solid solution amount of Si is preferably 120 to 600 ppm, more preferably 150 to 600 ppm, and still more preferably 150 to 500 ppm.
When the solid solution amount of Si is within this range, the electrolytic roughened surface becomes uniform, and pits having average opening diameters of 0.01 to 0.05 μm and 0.05 to 1.5 μm are uniform over the entire surface. Formed.

  Fe is an element that hardly dissolves in aluminum and remains as an intermetallic compound.

In the present invention, the Fe content is preferably 0.11 to 0.45 mass%, more preferably 0.15 to 0.45 mass%, and 0.20 to 0.43 mass%. More preferably.
When the Fe content is within this range, Fe is dispersed as a fine intermetallic compound, and as a result of acting as a starting point for the electrolytic roughening treatment, the electrolytic roughened surface becomes uniform.

In the present invention, from the viewpoint of securing the necessary Fe intermetallic compound, the solid solution amount of Fe is preferably 100 ppm or less, more preferably 50 ppm or less, and further 40 ppm or less. preferable.
From the viewpoint of ensuring the heat resistance of the aluminum alloy plate, the solid solution amount of Fe is preferably 10 ppm or more.

Cu is an important element in controlling the electrolytic surface roughening treatment, but is an optional element in the present invention.
In the present invention, from the viewpoint of maintaining the uniformity of electrolytic surface roughening, the content when Cu is contained is preferably 0.030% by mass or less.

  Since the grain refinement element does not affect the uniformity of the electrolytic surface roughening, it 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 alloy plate is made of Al and inevitable impurities.
As this inevitable impurity, Mg, Mn, Zn, Cr, Zr, V, Zn, Be etc. are mentioned, for example, These may each be contained 0.05 mass% or less.
Moreover, most of inevitable impurities are contained in the Al ingot. For example, if the inevitable impurities are contained in a metal having an Al purity of 99.5%, 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 described above, the present inventor has found that a relatively large intermetallic compound serves as a starting point for a relatively large recess formed by the surface roughening treatment, and the surface has an equivalent circle diameter of 0.2 μm or more. By using an aluminum alloy plate having more than 35000 intermetallic compounds / mm ² , a lithographic printing plate capable of suppressing the generation of pot-like residual film and development residue and obtaining a lithographic printing plate excellent in stain resistance We found that the original version was obtained.
Here, in the aluminum alloy plate of the present invention in which Si and Fe are essential, as the intermetallic compound, specifically, for example, Al ₃ Fe, Al ₆ Fe, Al _m Fe, α-AlFeSi, β -AlFeSi etc. are mentioned.
Of these, metastable intermetallic compounds (α-AlFeSi, β-AlFeSi, Al ₆ Fe) are preferable, and α-AlFeSi is more preferable.

In the present invention, regardless of the type of the intermetallic compound, by equivalent circle diameter with more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ^2, suppress the occurrence of pepper-like residual film and development scum it can. As described above, this is presumably because a large number of intermetallic compounds exist, and as a result, a relatively large intermetallic compound that becomes a starting point of a pot-like residual film and development residue is reduced.
Also, for reasons that can further suppress the occurrence of pepper-like residual film and development scum, is preferably equivalent circle diameter having the above intermetallic compound 0.2 [mu] m 40 000 pieces / mm ² or more, from 40,000 to 70,000 pieces / mm ² More preferably.
Furthermore, for the same reason, the average diameter of the intermetallic compound is preferably 0.2 to 1.0 μm, and more preferably 0.3 to 0.5 μm.

In the present invention, the intermetallic compound, for reasons that can further suppress the occurrence of pepper-like residual film is preferably a circle equivalent diameter intermetallic compounds than 1.0μm is 2500 / mm ² or less , More preferably 2000 pieces / mm ² or less, still more preferably 1500 pieces / mm ² or less.

Here, the number of intermetallic compounds and the average diameter are measured by the following methods.
First, an aluminum alloy plate obtained by wiping off the oil on its surface with acetone is used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate is taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Subsequently, five images arbitrarily selected from the obtained reflected electron images are stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. Specify the equivalent circle diameter (equivalent circle diameter) to obtain the particle size distribution.
From the result of this particle size distribution, the number of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more is calculated. This calculation is performed by rounding off the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.
Similarly, from the result of the particle size distribution, the average value of the equivalent circle diameters of the intermetallic compounds is calculated as the average diameter.
The number of intermetallic compounds is the same on the back surface of the aluminum alloy plate that has not been subjected to the surface roughening treatment after the surface treatment is performed and the lithographic printing plate support or the lithographic printing plate precursor is produced. Can be measured.

The inventors have also found that the size and number of intermetallic compounds of the aluminum alloy plate can be set to appropriate values by setting the heat treatment temperature and time to appropriate values.
In the present invention, in order to obtain an aluminum alloy plate suitable for an electro-roughened lithographic printing plate support, the size and number of intermetallic compounds are set to specific values using a continuous casting and rolling method. preferable.

The aluminum alloy sheet of the present invention is obtained by continuous casting in which molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. Is preferred.
Rolling by continuous casting has a high solidification rate on the surface of the cast material, so that the crystallized material is fine and uniform, does not require the homogenization heat treatment of the ingot required by the DC casting method, and is not subjected to long-time processing. Therefore, it is suitable as a base plate for a lithographic printing plate support.

Specifically, the following method is preferably exemplified.
First, a molten aluminum alloy adjusted to a predetermined alloy component content can be subjected to a cleaning treatment as necessary according to a conventional method.
Examples of the cleaning treatment include degassing treatment for removing unnecessary gases such as hydrogen in the molten metal (eg flux treatment using argon gas, chlorine gas, etc.); ceramic tube filter, ceramic foam filter, etc. A filtering process using a so-called rigid media filter, a filter using alumina flakes, alumina balls, or the like as a filter medium, a glass cloth filter, or the like; a process in which such a degassing process and a filtering process are combined;

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

Next, continuous casting is performed using a molten metal that has been subjected to a cleaning treatment as necessary.
Continuous casting is a process in which a molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. Method), a method using a cooling roll represented by the 3C method, a double belt method (Hasley method), a method using a cooling belt or a cooling block represented by the Al-Swiss Caster II type, and the like.
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. Moreover, it solidifies in the range whose cooling rate is 100-1000 degrees C / sec.
Regarding the continuous casting method, the techniques proposed by the present applicant 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.

In continuous casting, 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 continuously cast, and the hot rolling step can be omitted. Benefits are gained.
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.
In the present invention, from the viewpoint of producing a large number of intermetallic compounds, a method using a cooling roll is preferred, and the plate thickness is preferably 7 mm or less.

  After the continuous casting, the obtained aluminum alloy plate is finished to a predetermined thickness, for example, a thickness of 0.1 to 0.5 mm, through a cold rolling process or the like applied as necessary.

In the present invention, intermediate annealing treatment may be performed from the viewpoint of increasing the Si solid solution amount or suppressing the Fe solid solution amount before, after, or during the cold rolling. Further, the appropriate intermediate annealing treatment has an effect of making the crystal grains fine, and the surface quality can be improved.
From the viewpoint of optimizing the size and number of intermetallic compounds, it is desirable to avoid the intermediate annealing treatment from being performed at an excessively high temperature or excessively for a long time. In particular, it is desirable to avoid heat treatment exceeding 550 ° C. or heat treatment exceeding 36 hours. This is because the intermetallic compound may be re-dissolved in aluminum, or a metastable intermetallic compound such as α-AlFeSi or β-AlFeSi may be changed to stable phase Al ₃ Fe. is there.
As a suitable condition for the intermediate annealing treatment, a batch annealing furnace is used at 280 to 550 ° C. for 2 to 20 hours, preferably 350 to 550 ° C. for 2 to 10 hours, more preferably 350 to 550 ° C. for 2 hours or more. Conditions for heating for less than 5 hours, more preferably conditions for heating at 350 to 550 ° C. for 2 to 4 hours; heating at 400 to 550 ° C. for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less using a continuous annealing furnace Condition; etc. are mentioned.

The flatness of the aluminum alloy 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 alloy plate is cut into a sheet shape, but in order to improve productivity, it is preferably performed in a continuous coil state.
Further, a slitter line may be used for processing into a predetermined plate width.
Furthermore, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum alloy plates, you may provide a thin oil film on the surface of an aluminum alloy plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

(Roughening treatment)
The lithographic printing plate support of the present invention is roughened on the surface of an aluminum alloy plate obtained through the above-described continuous casting process and various processes (for example, an intermediate annealing process, a cold rolling process, etc.) performed as desired. It is obtained by processing.
As the roughening treatment, generally one of mechanical roughening treatment, chemical roughening treatment and electrochemical roughening treatment (hereinafter also referred to as “electrolytic roughening treatment”) or Two or more combinations are used.
In the present invention, as the surface roughening treatment, it is preferable to perform at least electrolytic surface roughening treatment and to perform alkali etching treatment (first alkali etching treatment) before the electrolytic surface roughening treatment. It is preferable to perform an alkali etching process (second alkali etching process) later.

As the surface roughening treatment, electrochemical surface roughening treatment is preferably performed twice, and an etching treatment in an alkaline aqueous solution is preferably performed between them. 1 alkali etching treatment), desmut treatment in acidic aqueous solution (first desmut treatment), electrochemical roughening treatment in aqueous solution containing nitric acid or hydrochloric acid (first electrolytic roughening treatment), in alkaline aqueous solution Etching treatment (second alkali etching treatment), desmutting treatment in acidic aqueous solution (second desmutting treatment), electrochemical surface roughening treatment in aqueous solution containing hydrochloric acid (second electrolytic surface roughening treatment) Etching treatment in alkaline aqueous solution (third alkaline etching treatment), desmutting treatment in acidic aqueous solution (third desmutting treatment), and anodizing treatment in this order Be treated are preferably exemplified.
Moreover, it is preferable to perform a mechanical surface-roughening process before the said alkali etching process (1st alkali etching process).
Furthermore, it is also preferable to perform sealing treatment and hydrophilization treatment after the anodizing 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.

<Mechanical roughening>
In this invention, it is preferable to perform the mechanical roughening process performed in order to make the center average surface roughness of the surface of an aluminum alloy plate 0.35-1.0 micrometer.
Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.

The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is performed by rubbing one or both of the surfaces of the aluminum alloy 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 alloy plate surface can be adjusted.

  Further, 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 alloy plate. By adjusting the load, the depth of the recess formed on the surface of the aluminum alloy 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 from 2 to 100 μm, more preferably from 20 to 60 μm, from the viewpoint of excellent surface roughening efficiency and the ability to narrow the graining pitch. By adjusting the median diameter of the abrasive, the depth of the recess formed on the aluminum alloy plate surface 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 present applicant.

  Examples of the mechanical surface roughening process other than the brush grain method include a process of forming irregularities on the surface by transfer at the end of the cold rolling described above. In the present invention, instead of the brush grain method, or a brush Can be applied together with the grain method.

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

The first alkali etching treatment performed before the electrolytic surface roughening treatment (first electrolytic surface roughening treatment) is to smooth the uneven shape when the mechanical surface roughening is performed. When forming a uniform recess by the treatment (first electrolytic surface roughening treatment) and when mechanical surface roughening is not performed, the rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum alloy plate are removed. It is done for the purpose of doing.
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 12 g / m ² or less, more preferably 10 g / m ² or less, and still more preferably 8 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 electrolytic surface roughening treatment (first electrolytic surface roughening treatment), and further, the occurrence of 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 alkali 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 alkaline 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 alloy plate is continuously etched, the aluminum ion concentration in the alkaline solution increases and the etching amount of the aluminum alloy 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 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. 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 liquid increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the liquid amount constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature compensated. As the specific gravity meter, a differential pressure type is preferably used.

  Examples of the method of bringing the aluminum alloy plate into contact with the alkaline solution include, for example, a method of passing the aluminum alloy plate through a tank containing an alkaline solution, a method of immersing the aluminum alloy plate in a tank containing an alkaline solution, and an alkali. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.

  Among these, a method of spraying an alkaline solution onto the surface of the aluminum alloy 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 liquid film is a water storage tank for storing water, a water supply pipe for supplying water to the water storage tank, and a free-fall curtain liquid film from the water storage tank to the aluminum alloy plate. And a rectifying unit.
In this apparatus, water is supplied to the water supply tank from the water supply cylinder, and when the water overflows from the water supply tank, the water is rectified by the rectifying unit, and a free-falling curtain-like liquid film is supplied to the aluminum alloy 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 alloy plate is 30-80 degrees with respect to a horizontal direction.

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

  Moreover, as a spray tube used for the water washing process, for example, a spray tube having a plurality of spray tips spreading in a fan shape in the width direction of the aluminum alloy plate 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, it is preferable to perform pickling (first desmutting treatment) in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing the aluminum alloy 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 desmutting process performed after the first alkali etching process, when nitric acid electrolysis is continuously performed as the electrolytic surface roughening process (first electrolytic surface roughening process), an electrolytic solution used for nitric acid electrolysis is used. It is preferable to use an overflow waste liquid.

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 acid and 0.1 to 5 g / L 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 an aluminum alloy plate into contact with an acidic solution include a method of passing an aluminum alloy plate through a tank containing an acidic solution, a method of immersing an aluminum alloy plate in a tank containing an acidic solution, and an acidic solution. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.
Among these, a method in which an acidic solution is sprayed on the surface of the aluminum alloy 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 desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.
In the first desmut process, when using an overflow waste liquid of the electrolyte used for the subsequent nitric acid electrolysis as the desmut process liquid, after the desmut process, the draining with a nip roller and the water washing process are not performed. It is preferable to handle the aluminum alloy plate until the nitric acid electrolysis step while spraying a desmut treatment liquid as necessary so that the surface does not dry.

<First electrolytic surface roughening treatment>
The first electrolytic surface roughening treatment is an electrolytic surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid.
In the present invention, the first electrolytic surface roughening treatment is preferably a treatment using a trapezoidal waveform alternating current in an electrolytic solution containing nitric acid because the latitude of the electrolytic surface roughened surface is increased. It is preferable to use a sinusoidal alternating current in the electrolyte solution containing selenium because it is easy to control the surface shape of the electrolytically roughened surface.
The average roughness R _a of the aluminum alloy plate surface of the first electrolytic graining treatment is preferably 0.2 to 1.0 [mu] m.

(Electrolytic roughening treatment in aqueous solution containing nitric acid (nitric acid electrolysis))
A suitable uneven structure can be formed on the surface of the aluminum alloy plate by nitric acid electrolysis. In the present invention, when the aluminum alloy 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 of the present invention has excellent printing durability.

The aqueous solution containing nitric acid can be one used for electrochemical surface roughening using ordinary direct current or alternating current, and an aqueous solution of nitric acid having a concentration of 1 to 100 g / L can be used for 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.

In order to obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum alloy plate up until the electrolysis reaction is completed is preferably at 150C / dm ² or more, 170C / dm ² or more more preferably is, but preferably not 600C / dm ² or less, more preferably 500C / dm ² or less.
The current density at this time is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² in terms of current peak value.

(Electrolytic roughening treatment in aqueous solution containing hydrochloric acid (hydrochloric acid electrolysis))
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 metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, and a silica, may melt | dissolve in the aqueous solution containing hydrochloric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L. Furthermore, the above-mentioned compound which forms a complex with copper can also be added at a rate of 1 to 200 g / L. Moreover, sulfuric acid can also be added at a rate of 1 to 100 g / L.

Furthermore, the aqueous solution containing hydrochloric acid has an aluminum ion concentration of 3 to 7 g / L, preferably by adding an aluminum salt (aluminum chloride, AlCl ₃ .6H ₂ O) to an aqueous solution containing 2 to 10 g / L of hydrochloric acid. Particularly preferred is an aqueous solution of 4 to 6 g / L.
When electrolytic surface roughening is performed using such an aqueous hydrochloric acid solution, the surface roughened electrolytic surface becomes more uniform, and even if a low purity aluminum alloy plate is used, a high purity aluminum alloy plate is used. Even in this case, processing unevenness does not occur, and it is possible to achieve both excellent printing durability and stain resistance when using a planographic printing plate.

  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 to 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, it is possible to form fine irregularities on the surface by applying a slight current. The fine irregularities have an average opening diameter (pit diameter) of 0.01 to 1.5 μm and are uniformly generated on the entire surface of the aluminum alloy plate.
Further, when the amount of electricity is increased (the total amount of electricity (anode reaction) is 150 to 2000 C / dm ² ), the average opening diameter is 1 to 30 μm having pits with an average opening diameter of 0.01 to 0.4 μm on the surface. A pit is generated. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum alloy 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.

In hydrochloric acid electrolysis, the current density is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² at the peak current value.

  When the aluminum alloy plate is subjected to hydrochloric acid electrolysis with the above-mentioned large electric quantity, large waviness and fine irregularities can be formed at the same time, and by making the large waviness more uniform by the second alkali etching process described later, the stain resistance is improved. Can be improved.

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

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.

As the aluminum alloy plate is continuously subjected to electrolytic surface roughening, the aluminum ion concentration in the alkaline solution increases, and the shape of the irregularities of the aluminum alloy plate formed by the first electrolytic surface roughening treatment varies. To do. 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 electric conductivity, the ultrasonic wave propagation speed and the temperature, and nitric acid or hydrochloric acid and water are added so as to reach the control target value of the liquid composition. Then, the electrolytic solution increased by adding nitric acid or hydrochloric acid and water is overflowed from the circulation tank, so that the amount of the electrolytic solution 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 specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measuring the liquid composition are used for measurement after being controlled at a constant temperature (eg, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

The 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 is the one 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, in an indirect power feeding method in which no conductor roll is used for aluminum, a duty ratio is used. 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. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is easily affected by the inductance component on the power supply circuit, and the power supply cost is increased.

FIG. 3 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. For the purpose of controlling the current ratio between the alternating current anode and cathode applied to the aluminum alloy plate facing the main electrode to achieve uniform graining and dissolving the carbon of the main electrode, it is shown in FIG. Thus, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 3, 11 is an aluminum alloy plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. Yes, 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 anode acting on the aluminum alloy 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 rectifying element or a switching element It is possible to control the ratio between the current value for the reaction and the current value for the cathode reaction. On the aluminum alloy 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 supply wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity. 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 anodes and cathodes arranged alternately, and an aluminum alloy plate is spaced from the anode and cathode. If it can be passed, 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 alloy plate in the traveling direction between the anode and the cathode, changing the passing speed of the aluminum alloy plate, changing the flow rate of the electrolyte, the temperature, the liquid composition, the current density, etc. The structure 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 surface roughening treatment is finished, 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 a 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 alloy 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 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 surface roughening process and the second electrolytic surface roughening process includes dissolving the smut generated in the first electrolytic surface roughening process, and the first electrolytic roughing process. This is performed for the purpose of dissolving the edge portion of the pit formed by the surface treatment.
As a result, the edge portion of the large pit formed by the first electrolytic surface roughening treatment is melted and the surface becomes smooth, and the ink is less likely to be caught on the edge portion, so that a lithographic printing plate having excellent stain resistance is obtained. be able to.
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, the edge portion of the pit generated by the first electrolytic surface roughening process becomes smooth in the non-image portion of the lithographic printing plate, and the ink is difficult to get caught. Excellent in properties. On the other hand, when the etching amount is 4 g / m ² or less, the unevenness generated by the first electrolytic surface roughening treatment becomes large, and thus 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 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 acid and 0.1 to 8 g / L 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, and preferably 60 ° C. or lower. More preferred.

<Second electrolytic surface roughening treatment (second hydrochloric acid electrolysis)>
The second electrolytic surface roughening 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 surface roughening treatment described above may be used, but by combining this second electrolytic surface roughening treatment, a more complicated uneven structure can be formed on the surface of the aluminum alloy plate, As a result, the printing durability can be improved.

The second electrolytic surface roughening treatment is basically the same as the hydrochloric acid electrolysis described in the first electrolytic surface roughening treatment.
The total amount of electricity that the aluminum alloy plate takes part in the anodic reaction by electrochemical surface roughening in an aqueous solution containing hydrochloric acid in the second electrolytic surface roughening treatment is the time when the electrochemical surface roughening treatment is completed. in may be selected from the range of 10~200C / dm ^2, to first electrolytic graining increase destroying not formed was roughened by treatment is preferably ^{10~100C / dm 2, 50~80C / dm} 2 is Particularly preferred.

<First Alkaline Etching Treatment-First Electrolytic Roughening Treatment (Nitric Acid Electrolysis) -Second Alkaline Etching Treatment-Second Electrolytic Roughening Treatment (Second Hydrochloric Acid Electrolysis)>
When performing the above treatment in combination, nitric acid electrolysis in which the total amount of electricity in the anodic reaction is 65 to 500 C / dm ² in the electrolytic solution containing nitric acid, and alkaline etching in which the dissolution amount is 0.1 g / m ² or more. Treatment, second hydrochloric acid electrolysis in which the total amount of electricity in the anodic reaction is 25 to 100 C / dm ² in an electrolytic solution containing hydrochloric acid, and alkaline etching treatment in which the dissolution amount is 0.03 g / m ² or more. It is preferable to apply in order.
By roughening with this combination, a lithographic printing plate support capable of obtaining a lithographic printing plate having better stain resistance and printing durability can be obtained.

<Third alkali etching treatment>
The third alkali etching process performed after the second electrolytic surface roughening process is performed by dissolving the smut generated by the second electrolytic surface roughening process and the edge of the pit formed by the second electrolytic surface roughening process. This is done for the purpose of dissolving the part. 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, the edge portion of the pit generated by the second hydrochloric acid electrolysis becomes smooth in the non-image portion of the lithographic printing plate, and the ink is difficult to catch, 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 electrolytic surface roughening treatment and the second electrolytic surface roughening treatment becomes large, and thus 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 caused by the hydrochloric acid alternating current electrolysis in the previous stage too small, the concentration is 100 g / L or less. It is preferable that it is 70 g / L or less.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, and 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, pickling (third desmutting treatment) is preferably performed 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 5-400 g / L acid and 0.5-8 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, and preferably 60 seconds or shorter, more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of liquid as the electrolyte used in the subsequent anodizing process is used as the desmut process liquid, the draining with a nip roller and the water washing process can be omitted after the desmut process.

<Anodizing treatment>
It is preferable to anodize the aluminum alloy plate treated as described above.
The anodizing treatment can be performed by a method conventionally used in this field.
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.
Of these, it is preferable to perform anodization using an electrolytic solution containing sulfuric acid and / or phosphoric acid.
When an electrolytic solution containing sulfuric acid is used, for example, an anodized film can be formed by energizing an aluminum alloy plate as an anode in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less. .
Moreover, when using the electrolyte solution containing phosphoric acid, it can energize by making an aluminum alloy plate into an anode in the aqueous solution containing 10-40 mass% phosphoric acid, for example, and can form an anodic oxide film.

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

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, electrolysis time 15 seconds to 50 minutes are appropriate, and the amount of anodic oxide film is adjusted as desired.

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

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

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

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

When anodizing is performed in an electrolytic solution containing sulfuric acid, a direct current may be applied between the aluminum alloy plate and the counter electrode, or an alternating current may be applied.
When a direct current is applied to the aluminum alloy plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case of continuous anodizing treatment, at the beginning of anodizing treatment, so as not to cause so-called "burn" (part where the film becomes thicker than the surroundings) due to current concentration on a part of the aluminum alloy plate. It is preferable to increase the current density to 30 to 50 A / dm ² or higher as the anodic oxidation process proceeds with a current flowing at a low current density of 5 to 10 A / m ² .
Specifically, it is preferable that the current distribution of the DC power supply is set so that the current of the downstream DC power supply is equal to or greater than the current of the upstream DC power supply. By using such current distribution, so-called burning is less likely to occur, and as a result, high-speed anodization can be performed.
When the anodizing treatment is continuously performed, it is preferable that the anodization is performed by a liquid power feeding method in which power is supplied to the aluminum alloy 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. it is a 800 pieces / μm ² about.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, while 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 . Further, it is preferable that the difference in the amount of the anodized film between the center portion of the aluminum alloy 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. 4 is preferably used. FIG. 4 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum alloy plate.

  In the anodizing apparatus 410 shown in FIG. 4, in order to energize the aluminum alloy plate 416 via the electrolytic solution, a feeding tank 412 is provided upstream in the traveling direction of the aluminum alloy plate 416, and an anodizing treatment tank is provided downstream. 414 is installed. The aluminum alloy plate 416 is conveyed by the pass rollers 422 and 428 as indicated by arrows in FIG. In the power supply tank 412 into which the aluminum alloy plate 416 is first introduced, an anode 420 connected to the positive electrode of the DC power supply 434 is installed, and the aluminum alloy plate 416 serves as a cathode. Therefore, a cathode reaction occurs in the aluminum alloy plate 416.

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

  Between the power supply tank 412 and the anodizing tank 414, it is preferable to provide a tank called an intermediate tank 413 in which the electrolytic solution does not accumulate as shown in FIG. By providing the intermediate tank 413, it is possible to prevent the current from bypassing the anode 420 to the cathode 430 without passing through the aluminum alloy 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 making the distribution of the electrolyte constant and preventing local current concentration of the aluminum alloy plate 416 in the anodizing tank 414, the liquid supply nozzles 436 and 438 are provided with slits, and the ejected liquid flow is changed in the width direction. It has a structure that makes it constant.

  In the anodizing bath 414, a shielding plate 440 is provided on the opposite side of the aluminum alloy plate 416 from the anode 430, and current flows on the opposite side of the surface of the aluminum alloy plate 416 where the anodized film is to be formed. Suppresses The distance between the aluminum alloy 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 carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Hydrophilic treatment>
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 Group 4 (Group IVA) metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

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

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

[Dry]
After obtaining the lithographic printing plate support as described above, it is preferable to dry the surface of the lithographic printing plate support before providing the image recording layer. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 20 seconds or shorter, and even more preferably 15 seconds.

[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 alloy 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]
(Image recording layer)
The lithographic printing plate support of the present invention can be provided with a thermal positive type image recording layer in which the alkali solubility of the exposed portion increases after infrared exposure to form the lithographic printing plate precursor of the present invention.
The image recording layer contains an alkali-soluble resin and an infrared absorber, and the infrared absorber converts the energy of infrared light into heat, and the heat reduces the alkali solubility of the alkali-soluble resin. It will be released efficiently.

  In the present invention, the image recording layer may have a single layer structure, but is preferably a multi-layered recording layer composed of at least two layers (an upper recording layer and a lower recording layer).

<Infrared absorber>
The infrared absorber contained in the image recording layer is a component that exhibits a photothermal conversion function. This infrared absorber has a function of converting the absorbed infrared rays into heat, and the laser scanning causes the cancellation of the interaction, the decomposition of the development inhibitor, the generation of acid, etc., and the solubility in the developer is greatly increased. . In addition, the infrared absorber itself may interact with the alkali-soluble resin to suppress alkali solubility.
In the case where the image recording layer has a multilayer structure, such an infrared absorber may be contained in at least one of the upper recording layer and the lower recording layer, but from the viewpoint of sensitivity, it is contained in the upper recording layer. Is preferred.
The infrared absorber used in the present invention is a dye or pigment that effectively absorbs infrared rays having a wavelength of 760 nm to 1200 nm, and is preferably a dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm.
The infrared absorber that can be suitably used for the lithographic printing plate precursor according to the invention will be described in detail below.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as 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 Is mentioned.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., naphthoquinone dyes, JP-A-58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .

Another example of a preferable dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.
Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, preferably in the range of 0.05 μm to 1 μm, from the viewpoint of the stability of the recording layer coating liquid and the uniformity of the recording layer to be formed. Is more preferable, and it is particularly preferable to be in the range of 0.1 μm to 1 μm.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  In the present invention, an infrared absorber that produces a positive action (dissolution of the unexposed portion in an alkaline developer is suppressed in the exposed portion and the dissolution suppressing action is canceled in the exposed portion) by interaction with the alkali-soluble resin is used. Therefore, those having an onium salt structure are particularly preferable because of their excellent action. Specifically, among the infrared absorbers exemplified above, cyanine dyes and pyrylium salts are particularly preferable.

In the present invention, an anionic infrared absorber described in JP-A-11-338131 can also be suitably used. This anionic infrared absorber refers to one having an anion structure without a cation structure in the mother nucleus of a dye that substantially absorbs infrared rays.
For example, (a-1) anionic metal complex and (a-2) anionic phthalocyanine are mentioned.
Here, the (a-1) anionic metal complex refers to an anion that becomes an anion in the central metal and the entire ligand of the complex part that substantially absorbs light.
(A-2) Anionic phthalocyanine refers to a phthalocyanine skeleton having an anion group such as a sulfonic acid, a carboxylic acid, or a phosphonic acid group bonded as a substituent to form an anion as a whole.
Furthermore, an anionic infrared absorber represented by [Ga ⁻ -M-Gb] _m X ^{m +} described in [0014] to [0105] of JP-A-11-338131 [Ga ⁻ represents an anionic substituent, and Gb represents Represents a neutral substituent. X ^{m +} represents a 1 to m-valent cation containing a proton, and m represents an integer of 1 to 6. Can be mentioned.

  The infrared absorber is preferably a dye, and preferable examples include infrared absorbers having an onium salt structure described in paragraphs [0018] to [0034] of JP-A No. 11-291652.

  For the purpose of further improving the sensitivity and development latitude, the image recording layer is provided with an infrared absorber exhibiting the ability to suppress dissolution of the above cyanine dyes, pyrylium salts, anionic dyes, and other dyes or pigments. It can also be used together.

  In the present invention, when the image recording layer is a single layer, the content of the infrared absorber is preferably 2 to 20% by mass and more preferably 3 to 15% by mass in the total solid content. preferable. Further, when the image recording layer has a multilayer structure, in the lower recording layer and the other recording layers, 0.01% of the total solid content of each recording layer is considered from the viewpoint of image forming property and suppression of occurrence of contamination in non-image areas. It is preferable that it is -50 mass%, It is more preferable that it is 0.1-20 mass%, It is still more preferable that it is 0.5-15 mass%.

  As will be described later, the infrared absorber may be contained in either the matrix phase or the dispersed phase when it is contained in the recording layer in which the dispersed phase is formed by using two or more polymers in combination, It may be included in both. When the latex constituting the dispersed phase contains desired components such as an initiator and an infrared absorber, it may be added together with the raw material when forming the latex particles, or may be introduced after forming the latex.

  Examples of the method of introducing after forming the latex include a method in which desired components such as an initiator, a color system, and a crosslinking agent to be introduced are dissolved in an organic solvent and added to a dispersion medium.

<Alkali-soluble resin>
(Phenolic resin)
Examples of the alkali-soluble resin contained in the image recording layer include a phenol resin.
Here, the phenol resin refers to a polymer compound having a phenolic hydroxyl group as an alkali-soluble group in the molecule.
Specific examples of the polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, xylenol cresol formaldehyde resin (3,5-, 2,3-, 2,4-, 2,5-xylenol), m -Novolec resins such as cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (which may be either m-, p-, or m- / p-mixed) mixed formaldehyde resin Pyrogallol acetone resin; and the like.
Of these, a novolak resin having a high ortho-position binding property, for example, xylenol cresol formaldehyde resin, m-cresol formaldehyde resin, and p-cresol formaldehyde resin are preferably contained in a large amount. The total alkali-soluble resin is preferably contained in an amount of 10% by mass or more, and more preferably 30% by mass or more.

In addition to this, as the polymer compound having a phenolic hydroxyl group, a polymer compound having a phenolic hydroxyl group in the side chain is preferably used.
As the polymer compound having a phenolic hydroxyl group in the side chain, a polymer compound obtained by homopolymerizing a polymerizable monomer comprising a phenolic hydroxyl group and a low molecular compound each having at least one unsaturated bond polymerizable with the phenolic hydroxyl group And a polymer compound obtained by copolymerizing this polymerizable monomer with another polymerizable monomer.

Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylate ester, methacrylate ester, and hydroxystyrene having a phenolic hydroxyl group.
Specific examples of the polymerizable monomer include N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, and N- (2-hydroxy). Phenyl) methacrylamide, N- (3-hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate , M-hydroxyphenyl methacrylate, p-hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethylacrylate 2- (3-hydroxyphenyl) ethyl acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- ( Suitable examples include 4-hydroxyphenyl) ethyl methacrylate.

  As a monomer component copolymerized with the polymerizable monomer which has a phenolic hydroxyl group, the compound mentioned to (m1)-(m12) shown below is mentioned, for example.

(M1) Acrylic acid esters or methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  As such a phenol resin, as described in U.S. Pat. No. 4,123,279, an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. As a preferred example of the alkali water-soluble polymer compound having a phenolic hydroxyl group of the present invention, a polycondensation product of phenol and formaldehyde having a substituent as a substituent.

As a synthesis method of the phenol resin, conventionally known graft copolymerization method, block copolymerization method, random copolymerization method and the like can be used.
The phenol resin causes strong hydrogen bondability in the unexposed area, and in the exposed area, some hydrogen bonds are easily released, so that it is suitable for a positive recording layer, and more preferably a novolac resin.
The phenol resin preferably has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 as measured by the GPC method.

When the image recording layer is a single layer, the content of the phenol resin in the image recording layer is preferably 3 to 50% by mass, and more preferably 5 to 40% by mass in the total solid content.
When the image recording layer has a multilayer structure, the phenol resin is preferably contained in the upper recording layer located near the surface (exposed surface). The content of the phenol resin in the inside is preferably 2 to 20% by mass, and more preferably 3 to 15% by mass in the total solid content of the upper recording layer.

(Other polymers)
As said alkali-soluble resin other than a phenol resin, the well-known polymer (resin) soluble in alkaline aqueous solution is mentioned, These can be used according to the objective. In particular, when the planographic printing plate precursor of the invention has a multilayer image recording layer, it is preferable to add these to the lower recording layer.

A polymer soluble in an alkaline aqueous solution (hereinafter referred to as “other polymer”) has at least a functional group such as a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, an active imino group, and a sulfonamide group. It is preferable.
Therefore, the other polymer is a monomer mixture containing one or more ethylenically unsaturated monomers having a functional group such as a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, an active imino group, a sulfonamide group, and combinations thereof. Can be suitably produced by polymerization.

Examples of the ethylenically unsaturated monomer include, in addition to acrylic acid and methacrylic acid, N- (4-carboxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, vinylphosphonic acid, 1,3 propylene glycol methacrylate. Examples include phosphate and 1,4-n-butylene glycol methacrylate phosphate.
Mixtures of these monomers can contain other ethylenically unsaturated comonomers. Examples of other ethylenically unsaturated comonomers include the following monomers.

  Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5- Acrylic esters such as hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate, tetrahydroacrylate;

  Aryl acrylates such as phenyl acrylate, furfuryl acrylate;

  Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, allyl methacrylate, amyl methacrylate hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl Methacrylic esters such as -3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate;

  Aryl methacrylates such as phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate;

N such as N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, Nt-butylacrylamide, N-heptylacrylamide, N-octylacrylamide, N-cyclohexylacrylamide, N-benzylacrylamide -Alkyl acrylamides;
N-aryl acrylamides such as N-phenylacrylamide, N-tolylacrylamide, N-nitrophenylacrylamide, N-naphthylacrylamide, N-hydroxyphenylacrylamide;

  N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dibutylacrylamide, N, N-dibutylacrylamide, N, N-diisobutylacrylamide, N, N-diethylhexylacrylamide, N, N-dicyclohexylacrylamide Such N, N-dialkylacrylamides;

  N, N-arylacrylamides such as N-methyl-N-phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide;

  N-methyl methacrylamide, N-ethyl methacrylamide, N-propyl methacrylamide, N-butyl methacrylamide, N-t-butyl methacrylamide, N-ethylhexyl methacrylamide, N-hydroxyethyl methacrylamide, N-cyclohexyl methacrylamide N-alkyl methacrylamides such as amides;

  N-aryl methacrylamides such as N-phenyl methacrylamide, N-naphthyl methacrylamide;

  N, N-dialkylmethacrylamides such as N, N-diethylmethacrylamide, N, N-dipropylmethacrylamide, N, N-dibutylmethacrylamide;

  N, N-diarylmethacrylamides such as N, N-diphenylmethacrylamide;

  Methacrylamide derivatives such as N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N-phenylmethacrylamide;

  Allyl compounds such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, allyloxyethanol;

  Hexyl vinyl ether, octyl vinyl ether, dodecyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethyl Aminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthra Vinyl ethers such as ether;

  Vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, vinyl phenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl vinyl esters such as β-phenyl butyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate;

  Styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, dodecyl styrene, benzyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl Styrene, methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, 2-bromo- Styrenes such as 4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene;

  Crotonic acid esters such as butyl crotonate, hexyl crotonate, crotonic acid, glycerol monocrotonate;

  Dialkyl itaconates such as dimethyl itaconate, diethyl itaconate, dibutyl itaconate;

  Dialkyls of maleic acid or fumaric acid such as dimethyl malate, dibutyl fumarate;

  N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, Maleimides such as N-cyclohexylmaleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide;

  Other nitrogen atom-containing monomers such as N-vinylpyrrolidone, N-vinylpyridine, acrylonitrile, methacrylonitrile

  Among these other ethylenically unsaturated comonomer monomers, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitriles are preferably used.

  In this invention, it is preferable that the weight average molecular weights measured by GPC method of the other polymer are 20,000-100,000. When the weight average molecular weight is less than 20,000, solvent resistance and abrasion resistance tend to be inferior, and when the weight average molecular weight exceeds 100,000, alkali developability tends to be inferior.

  In the present invention, when another polymer is contained in the lower recording layer, the content thereof is preferably in the range of 20 to 95% by mass with respect to the solid content of the lower recording layer. If the content is less than 20% by mass, it is inconvenient in terms of chemical resistance, and if it exceeds 95% by mass, it is not preferable in terms of exposure speed. Moreover, you may use together 2 or more types of other polymers as needed.

Furthermore, in the present invention, in the case of using another polymer in addition to the above-mentioned phenol resin in the lower recording layer, by using a phenol resin and another polymer that is incompatible with this phenol resin, This polymer forms a dispersed phase in the lower recording layer.
When used in such an embodiment, the content ratio (specific polymer: other polymer) with the phenol resin as the resin constituting the matrix phase in the lower recording layer and the other polymer constituting the dispersed phase is used in combination. The mass ratio is preferably 95: 5 to 60:40.

The lower recording layer composed of the dispersed phase and the matrix phase thus formed contains a high content of the above-described infrared absorber and a compound whose solubility in an alkaline solution is changed by heat, etc. in the dispersed phase. In particular, it is preferable to improve the solubility of the matrix phase in the alkaline solution.
Next, each compound contained in the dispersed phase other than the infrared absorber will be described.

<Acid generator>
The dispersed phase may contain an acid generator that decomposes with light or heat to generate an acid in order to improve the alkali solubility of the alkali-soluble resin in the exposed area.
Here, the acid generator refers to a compound that generates an acid upon irradiation with light having a wavelength of 200 to 500 nm or heating at 100 ° C. or higher, and specific examples thereof include a photoinitiator for photocationic polymerization and photoradical polymerization. Known acid generators used in photoinitiators, dye photodecolorants, photochromic agents, microresists, etc .; known compounds that generate acid upon thermal decomposition; mixtures thereof; and the like .
The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid.

Examples of the acid generator suitably used in the present invention include triazine compounds described in JP-A No. 11-95415, latent Bronsted acid described in JP-A No. 7-20629, and the like.
Here, the latent Bronsted acid refers to a precursor that decomposes to produce a Bronsted acid. Bronsted acid is believed to catalyze a matrix formation reaction between a resole resin and a novolak resin, and suitable Bronsted acids for this purpose include trifluoromethanesulfonic acid, hexafluorophosphonic acid, and the like.

Of the above latent Bronsted acids, ionic latent Bronsted acids can be preferably used in the present invention.
Ionic latent Bronsted acids include onium salts (eg, iodonium, sulfonium, phosphonium, selenonium, diazonium, arsonium salts).
Particularly useful onium salts include diphenyliodonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, phenylmethyl-ortho-cyanobenzylsulfonium trifluoromethanesulfonate, 2-methoxy-4-aminophenyldiazonium hexafluorophosphate, and the like. .

  Useful ionic latent Bronsted acids are those represented by the following formula:

In the formula, when X is iodine, R ³ and R ⁴ are lone pair, and R ¹ and R ² are aryl or substituted aryl group. When X is S or Se, R ⁴ is a lone pair, and R ¹ , R ² and R ³ may be an aryl group, a substituted aryl group, an aliphatic group or a substituted aliphatic group. When X is P or As, R ⁴ may be an aryl group, a substituted aryl group, an aliphatic group, or a substituted aliphatic group. W can be BF ₄ , CF ₃ SO ₃ , SbF ₆ , CCl ₃ CO ₂ , ClO ₄ , AsF ₆ , PF ₆ , or any corresponding acid whose pH is less than 3.

  Any onium salt described in US Pat. No. 4,708,925 can be used as the latent Bronsted acid. These include indonium, sulfonium, phosphonium, bromonium, chloronium, oxysulfoxonium, oxysulfonium, sulfoxonium, selenonium, telluronium, arsonium salts.

On the other hand, nonionic latent Bronsted acids are also suitably used in the present invention.
Nonionic latent Bronsted acid is a compound represented by the following formula (wherein X is Cl, Br, F, or CF ₃ SO ₃ , R is an aromatic group, aliphatic group or And a combination of an aromatic group and an aliphatic group.
RCH ₂ X, RCHX ₂ , RCX ₃ , R (CH ₂ X) ₂ , R (CH ₂ X) ₃

  In the present invention, it is particularly preferable to use a diazonium salt as the latent Bronsted acid.

  In the present invention, the content of these acid generators is 0.01 to 50% by mass with respect to the total solid content of the lower recording layer, from the viewpoints of image formability and prevention of non-image area contamination. Is more preferable, 0.1 to 25% by mass is more preferable, and 0.5 to 20% by mass is still more preferable.

<Additives>
In addition to the above-described components, the image recording layer can be used in combination with various known additives depending on the purpose.
When the image recording layer is a multi-layer type recording layer, it is preferable to form a dispersed phase in the lower recording layer as described above. Can be used.

  For example, a fluoropolymer is preferably added to the image recording layer for the purpose of improving the development resistance of the image area. Examples of the fluorine-containing polymer used in the image recording layer include fluorine-containing monomer copolymers as described in JP-A Nos. 11-288093 and 2000-187318.

  Preferable specific examples of the fluoropolymer include acrylic polymers containing fluorine of P-1 to P-13 described in JP-A No. 11-288093, and JP-A No. 2000-187318. Examples thereof include fluorine-containing polymers obtained by copolymerizing acrylic monomers containing A-1 to A33 with any acrylic monomer.

  As the molecular weight of the fluorine-containing polymer, those having a weight average molecular weight of 2000 or more and a number average molecular weight of 1000 or more are preferably used. More preferably, the weight average molecular weight is 5000 to 300000, and the number average molecular weight is 2000 to 250,000.

  Moreover, a commercially available fluorosurfactant can also be used as a fluorine-containing polymer having a preferable molecular weight. As specific examples, MegaFuck F-171, F-173, F-176, F-183, F-184, F-780, F-781 (all trade names) manufactured by Dainippon Ink & Chemicals, Inc. are used. Can be mentioned.

  These fluorine-containing polymers may be used alone or in combination of two or more. The addition amount is preferably 1.4% by mass or more, and more preferably 1.4 to 5.0% by mass with respect to the solid content of the image recording layer. When the amount is less than 1.4% by mass, the effect of improving the development latitude of the image recording layer, which is the purpose of adding the fluorine-containing polymer, cannot be sufficiently obtained. Even if it exceeds 5.0% by mass, the effect of improving the development latitude is not improved. On the other hand, there is a concern that the surface of the image recording layer may become hardly soluble due to the influence of the fluorine-containing polymer and the sensitivity may be lowered.

The image recording layer is further thermally decomposable, such as an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, if necessary. Substances (dissolution inhibitors) that substantially reduce the properties can be used in combination.
By adding a dissolution inhibitor, the ability to dissolve the image area into the developer is improved, and by adding this compound, an infrared absorber that does not form an interaction with an alkali-soluble resin should be used. Is also possible.
Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts.

  Preferred examples of the onium salt that can be used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Baletal, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, US Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140 Ammonium salts described in the C. Necker et al., Macromolecules, 17, 2468 (1984), C.I. S. Wenetal, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al., Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salt,

  J. et al. V. Crivello et al., Polymer J .; 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Wattal, J. et al. PolymerSci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al., Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al., Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 4,491,628, No. 5,041,358, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al., Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wenetal, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

As a dissolution inhibitor that can be used in the present invention, a diazonium salt is particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.
The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Among these, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance.
Examples of the o-quinonediazide compound used in the present invention include J. Although the compounds described in pages 339 to 352 of “Light Sensitive Systems” (John Wiley & Sons. Inc.) by Korser can be used, o-reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. Preferred are sulfonic acid esters or sulfonic acid amides of quinonediazide. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of each recording layer. These compounds can be used alone, but may be used as a mixture of several kinds.
The amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass.
The additive and binder of the present invention are preferably contained in the same layer.

  Further, for the purpose of enhancing the discrimination of the image and the resistance against scratches on the surface, a perfluoroalkyl group having 3 to 20 carbon atoms in the molecule as described in JP-A-2000-87318. A polymer having 2 or 3 (meth) acrylate monomers as polymerization components can be used in combination.

Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128. Trachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used.
As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 "-Trihydroxytriphenylmethane, 4,4 ', 3", 4 "-tetrahydroxy-3,5,3', 5'-tetramethyltriphenylmethane and the like.
Examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid , P-toluic acid, 3,4-methoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like.
The proportion of the cyclic acid anhydride, phenols and organic acids in the printing plate material is preferably 0.05 to 20% by mass, more preferably 0.1 to 5% by mass, particularly preferably 0.1 to 5% by mass. 10% by mass.

  Further, for example, a dye having a large absorption in the visible light region can be added to the image recording layer as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI52015), Eisenspiron Blue C-RH ( And dyes described in JP-A No. 62-293247, such as Hodogaya Chemical Co., Ltd.).

  By adding these dyes, the image portion and the non-image portion are clearly distinguished after the image formation, so that it is preferable to add them. The addition amount is preferably in the range of 0.01 to 10% by mass with respect to the total solid content of the recording layer.

  Furthermore, in the image recording layer, a nonionic surfactant as described in JP-A Nos. 62-251740 and 3-208514, Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane compounds as described in EP950517, and JP-A-11-288093 A copolymer containing a fluorine monomer as described above can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.
Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, DBE-621, DBE-712, DBP- manufactured by Chisso Corp. And polyalkylene oxide-modified silicones such as 732, DBP-534, and Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and amphoteric surfactant in the recording layer is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

To the lithographic printing plate precursor according to the invention, a printing-out agent for obtaining a visible image immediately after heating by exposure or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt.

  Specifically, for example, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A Nos. 50-36,209 and 53-8128, Trihalomethyl compounds and salts described in JP-A Nos. 53-36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440 Examples of such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images. Examples of other photoacid releasing agents include various o-naphthoquinonediazide compounds described in JP-A-55-62444; 2-trihalomethyl-5--5 described in JP-A-55-77742. Examples include aryl-1,3,4-oxadiazole compounds; diazonium salts.

  Furthermore, a plasticizer is added to the recording layer coating liquid in the present invention as needed to impart flexibility of the coating film. For example, butyl phthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

  The lithographic printing plate precursor according to the invention can be usually produced by sequentially applying a recording layer coating solution prepared by dissolving the above components in a solvent onto a suitable support.

  Suitable solvents for coating the recording layer include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2. -Propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, etc. However, it is not limited to this. These solvents are used alone or in combination. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.

  In principle, the lower recording layer and the upper recording layer recording layer (other recording layers) are preferably formed by separating the two layers.

  As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between a component contained in the lower recording layer and a component contained in the upper recording layer, or an upper recording layer is applied. Thereafter, a method of rapidly drying and removing the solvent can be used, but the method is not limited thereto.

  As a method of utilizing the difference in solvent solubility between the component contained in the lower recording layer and the component contained in the upper recording layer, the alkali contained in the lower recording layer is applied when the upper recording layer coating liquid is applied. The method of using the solvent which does not melt | dissolve soluble resin is mentioned. Thereby, even if it carries out 2 layer application | coating, it becomes possible to isolate | separate each layer clearly and to make a coating film. For example, as the lower recording layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the upper recording layer component is selected, and the component contained in the lower recording layer is selected. The lower recording layer is applied and dried using a solvent system that dissolves, and then the upper recording layer mainly composed of an alkali-soluble resin is dissolved in methyl ethyl ketone or 1-methoxy-2-propanol, and then applied and dried. Stratification becomes possible.

  When applying a solvent that does not dissolve the alkali-soluble resin contained in the lower recording layer when applying the upper recording layer coating solution, the alkali-soluble contained in the lower recording layer is used as the upper recording layer coating solvent. You may mix and use the solvent which melt | dissolves resin, and the solvent which does not melt | dissolve. By changing the mixing ratio of the two solvents, interlayer mixing between the upper recording layer and the lower recording layer can be arbitrarily controlled. When the ratio of the solvent that dissolves the alkali-soluble resin in the lower recording layer is increased, a part of the lower recording layer is dissolved when the upper recording layer is applied, and after drying, is contained as a particulate component in the upper recording layer, Due to this particulate component, protrusions are formed on the surface of the upper recording layer and scratch resistance is improved. On the other hand, when the lower recording layer component is dissolved into the upper recording layer, the film quality of the lower recording layer is lowered and the chemical resistance tends to be lowered. In this way, by controlling the mixing ratio in consideration of each physical property, various characteristics can be expressed, and further, partial compatibility between layers described later can be caused.

  From the viewpoint of the effect of the present invention, when the above mixed solvent is used as the coating solvent for the upper recording layer, the solvent for dissolving the alkali-soluble resin in the lower recording layer is 80% by mass or less of the upper recording layer coating solvent. Is preferable from the viewpoint of chemical resistance, and if considering the viewpoint of scratch resistance, it is preferably in the range of 10 to 60% by mass.

Next, after applying the second layer (upper recording layer), as a method of drying the solvent very quickly, a method of blowing high-pressure air from a slit nozzle installed substantially perpendicular to the running direction of the web, steam, etc. The method of giving thermal energy as conduction heat from the lower surface of a web from the roll (heating roll) supplied inside is mentioned, or the method of combining them.
Various methods can be used as a method for applying each layer such as a recording layer in the present invention. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, Examples thereof include roll coating.
In particular, in order to prevent damage to the lower recording layer when the upper recording layer is applied, the upper recording layer application method is preferably a non-contact type. Further, although it is a contact type, it is possible to use bar coater coating as a method generally used for solvent-based coating, but it is desirable to apply by forward driving to prevent damage to the lower recording layer. .

The coating amount after drying of the recording layer in the lithographic printing plate precursor according to the present invention is 0.7 to 4.0 g / m ^{2 in} the case of a single layer from the viewpoint of ensuring printing durability and suppressing the occurrence of residual film during development. It is preferably in the range, more preferably in the range of 0.8 to 3.0 g / m ² .
In the case of a multi-layer, the coating amount after drying of the lower recording layer is preferably in the range of 0.5 to 1.5 g / m ² from the viewpoint of ensuring printing durability and suppressing the generation of residual film during development. More preferably, it is in the range of 0.7 to 1.0 g / m ² , and the coating amount after drying of the upper recording layer is preferably in the range of 0.05 to 1.0 g / m ² , more preferably. Is in the range of 0.07 to 0.7 g / m ² . When there are two or more upper recording layers, this coating amount indicates the total amount.

  In the recording layer coating solution of the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant described in JP-A-62-170950 may be added. it can. A preferable addition amount is 0.01 to 1% by mass of the total solid content of the coating solution, and more preferably 0.05 to 0.5% by mass.

[Undercoat layer]
The lithographic printing plate precursor according to the invention is provided with the image recording layer on a support, and an undercoat layer can be provided between the support and the image recording layer as necessary.

  As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid; phenylphosphone having a substituent Organic phosphonic acids such as acids, naphthylphosphonic acids, alkylphosphonic acids, glycerophosphonic acids, methylenediphosphonic acids and ethylenediphosphonic acids; optionally substituted phenylphosphoric acids, naphthylphosphonic acids, alkylphosphoric acids and glycerophosphoric acids Organic phosphoric acids such as: phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, which may have substituents; amino acids such as glycine and β-alanine; hydrochloric acid of triethanolamine Hydroxy groups such as salts Amine hydrochloride having; selected from, etc., but may be used by mixing two or more.

  This organic undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the organic compound in an organic solvent or a mixed solvent thereof to adsorb the compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.

The coverage of the undercoat layer, from the viewpoint of printing durability, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2.

[Plate printing plate making method]
The plate making method of the lithographic printing plate of the present invention comprises an image recording step for recording an image on the lithographic printing plate precursor of the present invention by imagewise exposure, and a development having a pH of 9 or more on the lithographic printing plate precursor on which the image has been recorded. And a development step of obtaining a planographic printing plate by performing development using a liquid.

[Image recording process]
The image recording step is a step of recording an image on the lithographic printing plate precursor described above by imagewise exposure.
Here, the image-like exposure refers to image-like exposure through a transparent original image having a line image, a halftone dot image, or the like, or image-like exposure by laser beam scanning or the like using digital data.
As the exposure light source, a light source having a light emission wavelength from the near infrared region to the infrared region is used. Specifically, the image exposure is preferably performed by a solid-state laser and a semiconductor laser emitting infrared rays having a wavelength of 760 nm to 1200 nm.

[Development process]
The development step is a step of obtaining a lithographic printing plate by subjecting the lithographic printing plate precursor on which an image has been recorded in the image recording step to a development treatment using a developer having a pH of 9 or more.
The development process may be performed immediately after exposure, or a heat treatment may be performed between the image recording process and the development process. The conditions for the heat treatment are preferably 5 to 5 minutes within a range of 60 to 150 ° C. As the heating method, various conventionally known methods can be used. For example, a method of heating while contacting a recording material with a panel heater or a ceramic heater, a non-contact heating method with a lamp or hot air, and the like can be mentioned. This heat treatment can reduce the laser energy required for recording during laser irradiation.

As the developer and the replenisher used for the plate making of the lithographic printing plate precursor according to the invention, a conventionally known alkaline aqueous solution can be used.
The developer that can be applied to the development processing of the lithographic printing plate precursor according to the invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5.
A conventionally known alkaline aqueous solution can be used for the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

Further, an alkaline aqueous solution composed of a non-reducing sugar and a base can be used. Non-reducing sugar means a saccharide that does not have a free aldehyde group or ketone group and therefore has no reducing ability. Sugar sugars are classified into sugar alcohols reduced by hydrogenation of sugars. Any of these is preferably used in the present invention.
Examples of trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, durisit and allozulcit. Furthermore, maltitol obtained by hydrogenation of a disaccharide and a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide are preferably used. Among these, sugar alcohol and saccharose are particularly preferred non-reducing sugars, and D-sorbite, saccharose, and reduced syrup are particularly preferred because they have a buffering action in an appropriate pH region and are inexpensive.

These non-reducing sugars can be used alone or in combination of two or more thereof, and the proportion of the non-reducing sugar in the developer is preferably from 0.1 to 30% by mass, and more preferably from 1 to 20% by mass.
A conventionally known alkaline agent can be used as the base to be combined with the non-reducing sugar. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, Examples include inorganic alkali agents such as ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used.

  These alkali agents are used alone or in combination of two or more. Among these, sodium hydroxide and potassium hydroxide are preferable. The reason is that the pH can be adjusted in a wide pH range by adjusting the amount added to the non-reducing sugar. Further, trisodium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they themselves have a buffering action.

  When developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer so that a large amount of the lithographic plate can be obtained without replacing the developer in the developer tank for a long time. It is known that printing plate precursors can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer and the replenisher as necessary for the purpose of promoting or suppressing developability, dispersing development residue, and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, and organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added. The printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. When the lithographic printing plate precursor according to the invention is used as a printing plate, these treatments can be used in various combinations as post-treatments.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting a printing plate, processing liquid tanks and a spray device, and each pumped pump is pumped while horizontally transporting the exposed printing plate. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

  A method for processing a lithographic printing plate precursor according to the present invention will be described. After image exposure and development, there is an unnecessary image portion (for example, film edge mark of the original image film) on the lithographic printing plate obtained by performing any one or more of washing, rinsing and gumming. In that case, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-5-174842 can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with higher printing durability, Processing is performed. In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The The heating temperature and time in this case depend on the types of components forming the image, but are preferably in the range of 180 ° C. to 300 ° C. for 1 minute to 20 minutes.
The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted.
The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Production of aluminum alloy plate and lithographic printing plate support]
(Examples 1-6)
An aluminum alloy plate was manufactured by continuous casting using the molten aluminum alloy having the composition shown in Table 1 below and performing heat treatment (intermediate annealing) under the conditions shown in Table 2 below.
Specifically, first, continuous casting was performed using a molten aluminum alloy so that the cast plate thickness was 5.5 mm by twin roll type continuous casting.
Next, the obtained continuous cast plate was cold-rolled to a thickness of 0.9 mm, then subjected to intermediate annealing heat treatment under the conditions shown in Table 2 below, and further cold-rolled again to 0.3 mm. Finished with a thickness of.
Next, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the used aluminum alloy molten metal.

(Comparative Examples 1-2)
Using a molten aluminum alloy having the composition shown in Table 1 below, a slab was cast by DC casting and subjected to soaking and heat treatment (intermediate annealing) under the conditions shown in Table 2 below to produce an aluminum alloy plate.
Specifically, first, a 500 mm thick slab was cast by DC casting (Direct Chill) using a molten aluminum alloy.
Next, both sides of the obtained slab were chamfered by 20 mm and subjected to soaking at a temperature of 500 to 600 ° C.
Next, after hot rolling to a thickness of 3 mm, intermediate annealing was performed under the conditions shown in Table 2 below.
Next, after cold rolling and finishing to a thickness of 0.3 mm, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the molten aluminum alloy.

  The number per unit area of the intermetallic compound of each manufactured aluminum alloy plate was measured by the method shown below. The results are shown in Table 2 below.

(Number of intermetallic compounds per unit area and average diameter)
First, about each manufactured aluminum alloy board, what wiped off the oil of the surface with acetone was used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate was taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Subsequently, five images arbitrarily selected from the obtained reflected electron images were stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. The particle size distribution was obtained by specifying the equivalent circle diameter (equivalent circle diameter).
From the results of the particle size distribution, the number of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more and the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more were calculated. In addition, this calculation was performed by rounding off the average value of the number calculated from each of the five image data (particle size distribution) to the hundreds.
Similarly, from the result of the particle size distribution, the average value of the equivalent circle diameters of the intermetallic compounds was calculated as the average diameter.

  Each manufactured aluminum alloy plate was subjected to the following roughening treatment to produce a lithographic printing plate support.

<Roughening treatment>
As the roughening treatment, the following treatments (a) to (g) were performed. In addition, the water washing process was performed between all the process steps.

(A) Alkaline etching treatment 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 from a spray tube to each of the manufactured aluminum alloy plates to perform an etching treatment. The etching amount of the surface subjected to the electrochemical roughening treatment after the aluminum alloy plate was 3 g / m ² .
(B) Desmut treatment Next, a sulfuric acid aqueous solution (concentration: 300 g / L) having a temperature of 35 ° C. was sprayed from the spray tube for 5 seconds to perform desmut treatment.
(C) Electrolytic surface roughening treatment Thereafter, an electrolytic solution (liquid temperature 35 ° C.) in which aluminum chloride is dissolved in 1% by mass hydrochloric acid aqueous solution to have an aluminum ion concentration of 4.5 g / L is used, and a 60 Hz AC power source is used. Then, an electrochemical surface roughening treatment was continuously performed using a flat cell type electrolytic cell. A sine wave was used as the waveform of the AC power supply. In the electrochemical surface roughening treatment, the current density during the anode reaction of the aluminum alloy plate at the peak of alternating current was 30 A / dm ² . The ratio of the amount of electricity during the anode reaction of the aluminum alloy plate to the amount of electricity during the cathode reaction was 0.95. The amount of electricity was 480 C / dm ^{2 as the} total amount of electricity at the time of anode of the aluminum alloy plate. The electrolytic solution was stirred in the electrolytic cell by circulating the solution using a pump.
(D) Alkaline etching treatment An aqueous solution having a caustic soda concentration of 5% by mass, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. was sprayed from a spray tube onto the aluminum alloy plate to carry out an etching treatment. The etching amount of the surface subjected to the electrolytic surface roughening treatment of the aluminum alloy plate was 0.05 g / m ² .
(E) Desmut treatment A desmut treatment was performed by spraying an aqueous solution having a sulfuric acid concentration of 300 g / L, an aluminum ion concentration of 5 g / L, and a liquid temperature of 35 ° C. for 5 seconds from a spray tube.

(F) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having a structure shown in FIG. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .
(G) Polyvinylphosphonic acid treatment It was immersed for 10 seconds in a 40 ° C. aqueous solution containing 4 g / L of polyvinylphosphonic acid, washed with pure water, and dried.

[Manufacture of lithographic printing plate precursor]
The following thermal positive type image recording layer was provided on each lithographic printing plate support obtained by each surface roughening treatment to obtain a lithographic printing plate precursor.
Specifically, image recording layer coating liquids (1) and (2) having the following composition were prepared, and first, the image recording layer coating liquid (1) was applied so that the dry coating mass was 1.5 g / m ^2. And dried at 100 ° C. for 1 minute. Next, the image recording layer coating solution (2) is applied so that the dry coating mass is 0.5 g / m ² and dried at 100 ° C. for 1 minute to form a heat sensitive layer (thermal positive type image recording layer). A lithographic printing plate precursor was obtained.

<Image recording layer coating solution (1)>
・ Polymer A 6.01g
・ IR dye 1.06g
・ Byk307 0.21g
・ Γ-butyrolactone 9.27 g
1-methoxy-2-propanol 13.9g
・ Methyl ethyl ketone 60.26g
・ Water 9.27g

<Image recording layer coating solution (2)>
-1,5-naphthoquinonediazide-5-sulfonate ester of pyrogallol acetone condensate 0.15 g
・ Novolak resin (75% m-cresol / 25% p-cresol) 0.35 g
・ Ethyl violet 0.0014g
・ Byk307 0.015g
・ 6.2 g of 1-methoxy-2-propanol
・ MEK 3.3g

In the image recording layer coating solutions (1) and (2), the following polymers A, Byk307 and ethyl violet were used.
(Polymer A)
In a 250 ml 3-neck flask containing 70 g dimethylacetamide (DMAC) and 5 g water, methacrylic acid (20 mol%), acrylonitrile (67 mol%), N-phenylmaleimide (3 mol%) and methacrylamide ( Copolymer obtained by polymerizing 10 mol%) (Mw = 50,000)
(Byk307)
Polyether-modified polydimethylsiloxane (by Big Chemie Japan)
(Ethyl violet)
CAS: 2390-59-2, λmax: 596 nm

The obtained photosensitive lithographic printing plate precursor was imaged on a Trend setter manufactured by Creo at a beam intensity of 9 W and a drum rotation speed of 150 rpm. The exposure image included a solid image.
Thereafter, using a PS processor 900H manufactured by Fuji Film Co., Ltd. charged with an alkali developer having the following composition, the solution temperature was maintained at 30 ° C. and development was performed for 20 seconds to obtain a lithographic printing plate.

<Alkali developer composition>
・ Water 85% by mass
・ Glycerol 4% by mass
・ Methyl naphthalene sulfonate 4% by mass
・ 2-Phenoxyethanol 3% by mass
・ Sodium octyl sulfonate 3% by mass
・ Diethanolamine 1% by mass

(Print life)
The lithographic printing plate obtained above was used to print with a DIC-GEOS (N) ink made by Dainippon Ink & Chemicals, Inc. using a Lithrone printing machine made by Komori Corporation. The printing durability was evaluated according to the criteria shown below, based on the number of printed sheets when it was visually recognized that it started to become. The results are shown in Table 3 below.
○: More than 70,000 sheets ○ △: More than 50,000 sheets and less than 70,000 sheets △: More than 30,000 sheets and less than 50,000 sheets △ ×: Less than 30,000 sheets

(Stain resistance)
Blanket after printing 10000 sheets of DIC-GEOS (s) red ink on Mitsubishi Diamond F2 printer (Mitsubishi Heavy Industries, Ltd.) using the lithographic printing plate obtained above. Was visually confirmed and evaluated according to the following criteria. The results are shown in Table 3 below.
○: Blanket is not dirty ○ △: Blanket is slightly dirty but can be evaluated as good in practice △: Blanket is dirty but within acceptable range △ ×: Blanket is dirty and printed matter Obviously dirty

(Inhibition of pot-like residual film)
Using the lithographic printing plate obtained above, the non-image part after development of the sample exposed at each plate surface energy amount is observed with an optical microscope at a magnification of 100 times, and the number of pot-like residual films in an area of 1 cm ² is calculated. And evaluated according to the following criteria. The results are shown in Table 3.
○: 5 / cm ² or less of those ○ △: those 6-10 / cm ² △: 11 to 20 pieces / cm ² things △ ×: 21 to 30 pieces / cm ² things ×: 31 pieces / More than cm ²

(Development waste)
Using the lithographic printing plate obtained above, a test including a chart with a dot area ratio of 1 to 99% of 175 lpi / 2400 dpi on a Trendsetter 3244 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm A pattern image was drawn (exposure).
Next, using a PS processor LP-940HII manufactured by FUJIFILM Corporation, the development temperature was 30 ° C. and the development time was 12 seconds, and then a lithographic printing plate was produced by performing a gumming process. At this time, as a developing solution, a solution obtained by diluting a developing solution DT-2 manufactured by Fuji Film Co., Ltd. 1: 8 with water at pH = 13.2 and an organic solvent content of 0% was used. Further, as the gum solution, a solution obtained by diluting FG-1 manufactured by Fuji Film Co., Ltd. 1: 1 with water was used.
About the obtained lithographic printing plate, the adhesion number of the development residue of the surface was confirmed visually, and the following reference | standard evaluated. The results are shown in Table 3.
○: 0 / m ² ○ Δ: 1-2 / m ² △: 3 / m ² △ ×: 4-6 / m ² ×: 7 / m ² or more Things

From the results shown in Table 3, the planographic printing plate precursors of Comparative Examples 1 and 2 formed using an aluminum alloy plate having 35000 pieces / mm ² or less of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface It was found that the occurrence of a pot-like residual film was not suppressed, and the lithographic printing plate was inferior not only in stain resistance but also in printing durability. In particular, the lithographic printing plate precursor of Comparative Example 2 formed using an aluminum alloy plate having an intermetallic compound with an equivalent circle diameter of 1.0 μm or more on the surface of more than 2500 pieces / mm ² suppresses development debris generation. I found it impossible.
On the other hand, a lithographic printing plate precursor formed using an aluminum alloy plate having an intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface of more than 35000 pieces / mm ² has a pot-like residual film and development residue. It was found that the lithographic printing plate was suppressed in generation and excellent in not only stain resistance but also printing durability. In addition, it was found that the development of debris can be further suppressed as the intermetallic compound having an equivalent circle diameter of 1.0 μm or more decreases in a range of 2500 / mm ² or less.

DESCRIPTION OF SYMBOLS 11 Aluminum alloy 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 tank 50 Auxiliary anode tank 410 Anodizing process Device 412 Power supply tank 413 Intermediate tank 414 Anodizing treatment tank 416 Aluminum alloy 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 610 Anodizing Processing device 612 Power supply tank 614 Electrolytic treatment tank 616 Aluminum alloy plate 618, 626 Electrolytic solution 620 Power supply electrode 622, 628 Roller 624 Nip roller 630 Electrolytic electrode 632 Tank wall 634 DC power supply

Claims (10)

A lithographic printing plate precursor containing an alkali-soluble resin and an infrared absorber on a support and having an image recording layer in which the alkali solubility of an exposed portion increases after infrared exposure,
It said support circle on the surface equivalent diameter is formed using an aluminum alloy plate having more than the above intermetallic compound 0.2 [mu] m 35000 pieces / mm ^2,
Wherein among the intermetallic compound, the circle equivalent diameter is an intermetallic compound more than 1.0 .mu.m 2500 pieces / mm ² or less der Ru lithographic printing plate precursor having on the aluminum alloy plate. The lithographic printing plate precursor according to claim 1, wherein the support has 40,000 / mm ² or more of intermetallic compounds having an equivalent circle diameter of 0.2 µm or more on the surface .   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the alkali-soluble resin is a phenol resin.   The lithographic printing plate precursor according to claim 3, wherein the phenol resin is a novolac resin.   The planographic printing plate precursor according to any one of claims 1 to 4, wherein the aluminum alloy plate is produced by a continuous casting method.   The aluminum alloy plate is obtained by continuous casting in which molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. 5. The lithographic printing plate precursor as described in 5.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the support is a support obtained by subjecting the surface of the aluminum alloy plate to a roughening treatment including an electrochemical roughening treatment.   The lithographic printing plate precursor as claimed in claim 7, wherein the roughening treatment is a roughening treatment comprising an anodizing treatment after the electrochemical roughening treatment.   The lithographic printing plate precursor as claimed in claim 8, wherein the anodizing treatment is an anodizing treatment using an electrolytic solution containing sulfuric acid or phosphoric acid. An image recording step for recording an image by image-like exposure on the lithographic printing plate precursor according to any one of claims 1 to 9,
A lithographic printing plate making method comprising: a development step of obtaining a lithographic printing plate by subjecting the lithographic printing plate precursor on which an image has been recorded to a development treatment using a developer having a pH of 9 or more.