JP2011067971A - Original plate of lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate of lithographic printing plate excellent in printing resistance, fouling resistance and micro-corrosion fouling resistance. <P>SOLUTION: The original plate of lithographic printing plate has an image recording layer comprising an infrared ray-absorbing pigment (A) and a hydrophobic thermoplastic particle (B), on a support, wherein the support is formed by using an aluminum alloy plate in which the density, on the surface, of an inter-metallic compound having a circle-equivalent diameter of 0.2 μm or more is 35,000 pieces/mm<SP>2</SP>or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor.

  In general, a lithographic printing plate is composed of an oleophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. As such a lithographic printing plate, a PS plate in which an oleophilic photosensitive resin layer is provided on a hydrophilic support has been widely used. The plate making process in the conventional PS plate requires an operation of dissolving and removing the non-image area with a highly alkaline developing solution after exposure, and simplifies or eliminates such additional wet processing. This is one problem that has been desired to be improved with respect to the prior art. Particularly in recent years, disposal of the waste liquid discharged with wet processing has become a major concern for the entire industry due to consideration of the global environment, and the demand for improvement in this aspect has become even stronger.

  On the other hand, as another trend in this field in recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread. Various new image output methods have been put into practical use. Along with this, a computer that carries a digitized image information in a high-convergence radiation such as laser light, scans and exposes the original plate with this light, and directly produces a printing plate without using a lith film. To-plate technology is drawing attention.

  Among them, since solid-state lasers such as semiconductor lasers and YAG lasers have recently become available at low cost, plate-making methods using high-power density exposure using high-power lasers are promising. It has come to be.

  Among such lithographic printing plate precursors, one promising method suitable for simple development processing is to use a hydrophilic layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder polymer as an image recording layer. This is a lithographic printing plate precursor. When the image recording layer is exposed to light, the hydrophobic thermoplastic polymer particles are fused, and the hydrophilic layer surface is converted into an oleophilic image portion.

  Patent Documents 1 and 2 describe a method for preparing a lithographic printing plate in which an image recording layer having hydrophobic thermoplastic polymer particles is developed by a simple development method.

  However, it is difficult to sufficiently remove the non-image portion image recording layer containing such hydrophobic thermoplastic polymer particles by a simple developing means, and the image recording layer component remains in the non-image portion, There has been a problem of smudges in printing. In addition, when stored for a long period of time, a portion of the surface of the non-image area where ink easily adheres occurs, and dot-like or annular stains (hereinafter referred to as “micro-corrosion stains”) appearing on printed paper, etc. Sometimes occurred).

Patent Documents 3 to 5 describe lithographic printing plate precursor supports that focus on the intermetallic compound of the support, and are all inventions relating to a support having 35,000 intermetallic compounds / mm ² or less. .

JP 2003-255527 A Japanese Patent Laid-Open No. 2003-316021 JP 2002-160466 A Japanese Patent No. 3788943 JP 2002-88434 A

  The present inventor examined the cause of the occurrence of the micro-corrosion stains. First, the image recording layer having the hydrophobic thermoplastic polymer particles is an image recording layer in which the hydrophobic thermoplastic polymer particles are arranged. It was noticed that moisture was easily included in the image recording layer due to the influence of the above. The presence of moisture contained in the image-recording layer due to the influence of outside air and the hydrophilic component anionized by the moisture (hereinafter simply referred to as “anion”) causes corrosion of the aluminum alloy plate, thereby It was clarified that micro-corrosion stain was generated.

On the other hand, regarding the intermetallic compound of the aluminum alloy plate, for example, JP 2005-330588 A, JP 2005-232596 A, JP 11-151870 A and the like are included in an aluminum alloy plate for a lithographic printing plate. The contents regarding the intermetallic compound are described.
Specifically, the Al-Fe-based intermetallic compound is more likely to be a starting point of pits during electrolytic surface roughening than the Al-Fe-Si-based intermetallic compound, and among the Al-Fe-based intermetallic compounds, It is described that a metastable phase Al—Fe-based intermetallic compound tends to be a starting point of pits. JP-A-2005-330588 discloses that the number of metastable phase particles having a Fe / Al ratio of 0.6 or less is 0.35 or more with respect to the total number of intermetallic compound particles. It is described that eyes form. Furthermore, Japanese Patent Application Laid-Open No. 2005-232596 describes an aluminum alloy plate containing 0.5 to 2.0% of AlFe-based crystal precipitates on average. Japanese Patent Laid-Open No. 11-151870 is characterized in that the ratio of the number of Al—Fe intermetallic particles / the number of Al—Fe—Si intermetallic particles is 0.7 or more.
However, these patent documents do not describe an intermetallic compound for suppressing corrosion of the aluminum substrate by the image recording layer.

  Accordingly, an object of the present invention is to provide a lithographic printing plate precursor excellent in printing durability, stain resistance and microcorrosion stain resistance.

As a result of earnest research to achieve the above-mentioned object, the inventor uses a support made using an aluminum alloy plate having an intermetallic compound density of 35,000 pieces / mm ² or more on the surface, so that the printing durability, The inventors have found that a lithographic printing plate precursor excellent in stain resistance and microcorrosion stain resistance can be obtained, and completed the present invention.
That is, the present invention provides the following (1) to (8).

(1) In a lithographic printing plate precursor having an image recording layer containing (A) an infrared absorbing dye and (B) hydrophobic thermoplastic particles on a support,
A lithographic printing plate precursor, wherein the support is prepared using an aluminum alloy plate having a density of an intermetallic compound having a circle-equivalent diameter of 0.2 µm or more on the surface of 35000 pieces / mm ² or more.

  (2) The lithographic printing plate precursor as described in (1) above, wherein the hydrophobic thermoplastic particles are styrene-acrylonitrile particles.

(3) The aluminum alloy plate according to (1) or (2), wherein the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface is 2500 / mm ² or less. Lithographic printing plate precursor.

  (4) The peak count value of the Al—Fe intermetallic compound of the aluminum alloy plate measured using an X-ray diffractometer (XRD) is 400 cps or less, and the peak count value of the AlFeSi intermetallic compound is 30 cps. The lithographic printing plate precursor as described in any one of (1) to (3) above, wherein

  (5) An anodized film having micropores is formed on the surface of the support on which the image recording layer is formed, and the average pore diameter in the surface layer of the anodized film is 10 to 75 nm. The lithographic printing plate precursor as described in any one of (1) to (4) above, wherein the average value of the maximum diameter inside the pore is 1.1 to 3.0 times the average pore diameter.

  (6) The anodic oxide film is formed by an anodic oxidation treatment using an electrolytic solution containing sulfuric acid or phosphoric acid, according to any one of (1) to (5) above Lithographic printing plate precursor.

  (7) The lithographic printing plate precursor as described in any one of (1) to (6) above, wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method.

  (8) After performing image recording on the lithographic printing plate precursor as described in any one of (1) to (7) above, the plate surface is rubbed with the rubbing member in the presence of the processing liquid by an automatic processor equipped with the rubbing member. A method for producing a lithographic printing plate, comprising a step of rubbing and removing an image recording layer in a non-image area.

  According to the present invention, it is possible to obtain a lithographic printing plate precursor excellent in printing durability, stain resistance and microcorrosion stain resistance.

It is a graph which shows an example of the alternating waveform current waveform figure used for an electrochemical roughening process. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current. It is the schematic of the anodizing apparatus used for anodizing. It is a graph which shows an example of the sinusoidal waveform figure used for an electrochemical roughening process. FIG. 2 is a layout view showing a configuration of an automatic processor suitable for development processing of the lithographic printing plate preparation method of the present invention.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the invention is a lithographic printing plate precursor having an image recording layer containing (A) an infrared-absorbing dye and (B) hydrophobic thermoplastic particles on a support. In this case, the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more is prepared using an aluminum alloy plate having a density of 35000 pieces / mm ² or more.

As described above, since the image recording layer having hydrophobic thermoplastic polymer particles is an image recording layer in which hydrophobic thermoplastic polymer particles are arranged, the image recording layer is likely to include moisture due to the influence of outside air or the like. It has become. The presence of moisture contained in the image recording layer due to the influence of outside air or the like, and the presence of a hydrophilic component anionized by the moisture (hereinafter simply referred to as “anion”) causes corrosion of the aluminum alloy plate, thereby Micro-corrosion contamination occurs.
The present inventor, when an intermetallic compound having a large equivalent circle diameter exists on the surface of the aluminum alloy plate, tends to be a starting point of corrosion of the aluminum alloy plate when the image recording layer contains a lot of hydrophilic components. It was found that this tendency becomes remarkable when an intermetallic compound having a diameter of more than 1 μm is present.
If the density of the intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface is 35,000 / mm ² or more, the intermetallic compound having an equivalent circle diameter of more than 1 μm existing on the surface of the aluminum alloy plate Since the number is extremely small, the corrosion of the aluminum alloy plate and the resulting fine corrosion stains can be suppressed when the image recording layer contains many hydrophilic components.
From the viewpoint of suppressing minute corrosion stains, the density of the intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface of the aluminum alloy plate is preferably 50,000 pieces / mm ² or more.

In addition, new knowledge has been obtained that intermetallic compounds present on the surface of an aluminum alloy plate are effective starting points when electrochemically roughening the aluminum alloy plate. By using an aluminum alloy plate having an equivalent diameter of 0.2 μm or more and an intermetallic compound density of 35000 pieces / mm ² or more, the uniformity of the electrolytically roughened surface becomes better.

As described above, from the viewpoint of suppressing minute corrosion stains, it is preferable that the number of intermetallic compounds having an equivalent circle diameter of more than 1 μm existing on the surface of the aluminum alloy plate is small. Specifically, the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface of the aluminum alloy plate is preferably 2500 / mm ² or less, and more preferably 1500 / mm ² or less. .

Here, the number and density of intermetallic compounds on the surface of the aluminum alloy plate can be measured by the following method.
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 processing 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 the particle size distribution, the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more is calculated. This calculation is performed by rounding the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.
In addition, the number of intermetallic compounds having an equivalent circle diameter of 1 μm or more is calculated in the same procedure.
The density of the intermetallic compound on the surface of the aluminum alloy plate or the number of intermetallic compounds is the same on the back surface of the aluminum alloy plate on which the image recording layer is not formed after the lithographic printing plate precursor is produced. Can be measured.

The intermetallic compound present in the aluminum alloy plate varies depending on the type of metal element contained in the aluminum alloy plate, but in the case of a preferred embodiment of the aluminum alloy plate described later, which contains Al, Si and Fe as essential components, the aluminum alloy plate Specifically, examples of the intermetallic compound present in Al include an Al—Fe intermetallic compound such as Al ₃ Fe and Al ₆ Fe and an AlFeSi intermetallic compound such as α-AlFeSi and β-AlFeSi. .
The aluminum alloy plate used in the present invention has an Al content of 99% by mass or more, and from trace elements such as Si, Fe, Ni, Mn, Cu, Mg, Cr, Zn, Bi, Ti, and V It contains at least one element selected from the group consisting of:
The aluminum alloy plate used in the present invention is preferably a preferred embodiment of an aluminum alloy plate to be described later, which contains Al, Si and Fe as essential components.

As described above, in the preferred embodiment of the aluminum alloy plate containing Al, Si and Fe as essential components, the aluminum alloy plate includes an Al—Fe-based intermetallic compound such as Al ₃ Fe, Al ₆ Fe, or α- AlFeSi-based intermetallic compounds such as AlFeSi and β-AlFeSi, or both exist.
Among these, Al-Fe-based intermetallic compounds have obtained knowledge that when an image recording layer contains many hydrophilic components, they are the starting point of corrosion of aluminum alloy plates. From the viewpoint, it is preferable that the amount of the Al—Fe intermetallic compound contained in the aluminum alloy plate is small. Specifically, it is preferable that the peak count value of the Al—Fe-based intermetallic compound of the aluminum alloy plate, measured using an X-ray diffractometer (XRD), is 400 cps or less, and in particular, Al ₃ Fe and Al Both ₆ Fe peak count values are preferably 400 cps or less.
Here, the peak count value of the Al—Fe-based intermetallic compound means that an aluminum alloy plate is set in an X-ray diffractometer (for example, RAD-rR (12 kW rotating counter cathode type, manufactured by Rigaku Corporation), and the following conditions It was measured by.
・ Set tube voltage 50kV
・ Set tube current 200mA
・ Sampling interval 0.01 °
・ Scanning speed 1 ° / min ・ 2θ scanning range 10 ° ～ 70 °
Use of graphite monochromator From the viewpoint of suppressing minute corrosion stains, it is preferable that the peak count value of the Al—Fe intermetallic compound of the aluminum alloy plate is 200 cps or less, particularly both Al ₃ Fe and Al ₆ Fe. The peak count value is preferably 200 cps or less.

On the other hand, it has been found that Al—Fe—Si intermetallic compounds such as α-AlFeSi and β-AlFeSi are less likely to be a starting point of corrosion of an aluminum alloy plate than Al—Fe intermetallic compounds.
Among these, Al-Fe-based intermetallic compounds have obtained knowledge that when an image recording layer contains many hydrophilic components, they are the starting point of corrosion of aluminum alloy plates. From the viewpoint, it is preferable that the amount of the Al—Fe—Si intermetallic compound (particularly α-AlFeSi) contained in the aluminum alloy plate is large. Specifically, the peak count value of the Al—Fe—Si intermetallic compound (particularly α-AlFeSi) of the aluminum alloy plate measured using an X-ray diffractometer (XRD) is 30 cps or more. Preferably, it is 50 cps or more.

<Aluminum alloy plate (rolled aluminum)>
Hereinafter, the suitable aspect of the aluminum alloy plate used for this invention is described.
A preferred embodiment of the aluminum alloy plate used in the present invention is that the Al content is 99% by mass or more, 0.03 to 0.20% by mass of Si, and 0.11 to 0.45% by mass of Fe. The solid solution amount of Si is 120 to 600 ppm, and the solid solution amount of Fe is 100 ppm or less.
By using the preferred embodiment of the aluminum alloy plate described above, the stability of the electrolytic surface roughening treatment can be improved, and the uniformity of the electrolytic surface roughened surface can be enhanced. As a result, a support having a uniform electrolytic roughened surface can be obtained even under various electrolytic roughening treatment conditions. By using the support, lithographic printing excellent in printing durability and stain resistance is obtained. You can get the original version.
Although the essential alloy component in the suitable aspect of the aluminum alloy plate mentioned above is Al, Fe, and Si, you may contain copper (Cu) as an arbitrary 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 anodizing is performed after electrolytic surface roughening, defects in the anodized film are unlikely to occur. Thus, the stain resistance as a lithographic printing plate is also improved.

Moreover, in this invention, it is preferable that the solid solution amount of Si is 120-600 ppm, It is more preferable that it is 150-600 ppm, It is further more preferable that it is 150-500 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 these act as starting points for the electrolytic surface roughening treatment, so that the electrolytic surface roughened surface becomes uniform.

In the present invention, from the viewpoint of securing a necessary intermetallic compound of Fe, the solid solution amount of Fe is preferably 100 ppm or less, more preferably 50 ppm or less, and further preferably 40 ppm or less. preferable.
Further, 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.

The preferred embodiment of the aluminum alloy plate described above is preferably manufactured by a continuous casting method.
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 gas such as hydrogen in the molten metal (eg flux treatment using argon gas, chlorine gas, etc.); ceramic tube filter, ceramic foam filter, etc. Examples include 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 combining such a degassing process and a filtering process.

  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 generating a large number of intermetallic compounds, a method using a cooling roll is preferable, 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.
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 to 5 hours. Conditions for heating for a period of time; conditions for 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;

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 the 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 of the present invention is carried out by subjecting the surface of the aluminum alloy plate obtained through the above-described continuous casting process and various processes (for example, intermediate annealing process, cold rolling process, etc.) to be performed as desired. A support used for the plate precursor can be prepared.
As the roughening treatment, generally one or a combination of two or more of mechanical roughening treatment, chemical roughening treatment and electrochemical roughening treatment is 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), desmutting treatment in acidic aqueous solution (first desmutting 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.

When manufacturing the support body used for the lithographic printing plate precursor according to the invention, various processes 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 than pumicestone and is less likely to break, so it has better surface roughening efficiency. Further, aluminum hydroxide is suitable for the case where it is not desired to locally generate deep recesses because particles are damaged when an excessive load is applied.
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 propagation velocity, and temperature corresponding to the matrix of caustic soda concentration and aluminum ion concentration is prepared in advance, and the conductivity and specific gravity are prepared. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and caustic soda and water are added so that the control target value of the liquid composition is reached. Then, the amount of the etching solution increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the amount of the solution constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.

  Examples of the method of bringing the aluminum 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 subsequently performed as the electrolytic surface roughening process (first electrolytic surface roughening process), the electrolytic solution used for nitric acid electrolysis 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 holes of φ2 to 5 mm at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.
In the first desmutting process, when using the overflow waste liquid of the electrolyte used for the subsequent nitric acid electrolysis as the desmutting process liquid, the draining and rinsing processes with the nip roller are not performed after the desmutting process. 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 slag for the reason that 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.

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

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

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

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.
In this case, the current density 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, 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 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, preferably Particularly preferred is an aqueous solution of 4 to 6 g / L.
When electrolytic surface roughening treatment 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 in terms of 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.
Further, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 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, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a sine wave, a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is used. 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. A sine wave means what was shown in FIG.
A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 0.5 to 3 msec. When TP exceeds 3 msec, especially when an aqueous solution containing nitric acid is used, it becomes susceptible to the influence of trace components in the electrolytic solution typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining. Is difficult to be performed. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

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

FIG. 2 is a side view showing an example of a radial type cell used for electrochemical surface roughening using alternating current.
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, uniform graining, and dissolving the carbon of the main electrode are shown in FIG. Thus, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 2, 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 normal electrochemical surface roughening treatment using direct current can be used. Specifically, the same electrolyte solution used for the electrochemical surface roughening treatment using the alternating current can be used.

The DC power source wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity. 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 a platinum group metal oxide 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 passing water through the electrode to cool it.
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 passage speed of the aluminum alloy plate, changing the flow rate of the electrolyte, the liquid 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 completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing treatment for 1 to 10 seconds and then drain the liquid with a nip roller.
The washing treatment is preferably carried out using a spray tube. As 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 interval between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

<Second alkali etching treatment>
The second alkaline etching process performed between the first electrolytic surface roughening process and the second electrolytic surface roughening process includes dissolving the smut generated in the first electrolytic surface roughening process, and first electrolytic roughening 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, so that the ink is not easily caught on the edge portion. Obtainable.
Since the second alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the first electrolytic surface-roughening treatment becomes smooth and the ink is less likely 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 a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L so that the aluminum ion concentration becomes 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 longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 20 seconds or shorter. .
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 anode reaction is 65 to 500 C / dm ² in an 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 precursor 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 involves 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 alkali solution is preferably 30 g / L or more, and in order not to make the unevenness generated by the hydrochloric acid alternating current electrolysis in the previous stage too small, the concentration is 100 g / L or less. It is preferable that it is 70 g / L or less.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, preferably 50 g / L or less, more preferably 8 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

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

<Third desmut treatment>
After the third alkali etching treatment, 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. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum alloy plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

  Under the present circumstances, the component normally contained at least in an aluminum 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. ˜60 A / dm ² , voltage 1 to 100 V, and electrolysis time 15 seconds to 50 minutes are appropriate and adjusted so as to obtain a desired anodic oxide film amount.

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

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

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

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

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum alloy plate and the counter electrode, or 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 such that the current of the downstream DC power supply is equal to or greater than the current of the upstream DC power supply. By using such current distribution, so-called burning is less likely to occur, and as a result, high-speed anodization can be performed.
In the case where the anodic oxidation treatment is continuously performed, it is preferable to carry out by a liquid power feeding method in which power is supplied to the aluminum alloy plate through the electrolytic solution.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

Further, as described in JP-A-2-57391, it is preferable to use a phosphoric acid solution as the electrolytic solution. In the method described in JP-A-2-57391, a phosphoric acid solution is used as the electrolytic solution, the phosphoric acid concentration is 15 to 45% by mass, the electrolytic solution temperature is 20 to 70 ° C., and the current density is 2.0 amps / minute / dm. ^The anodizing treatment is performed under the conditions of ² or more, voltage of 50 V or more, and electrolysis time of 15 seconds to 3 minutes.
By carrying out the above procedure, the average pore diameter (surface average pore diameter) in the surface layer of the anodized film is 10 to 75 nm, preferably 20 to 50 nm, and the average value of the maximum diameter inside the pore (inside the pore) An anodic oxide film having an average value of the maximum diameter (1.1 to 3.0 times the average pore diameter) can be formed.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, whereas if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . 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. 3 is preferably used. FIG. 3 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. 3, in order to energize the aluminum alloy plate 416 via the electrolytic solution, the power supply tank 412 is provided upstream in the traveling direction of the aluminum alloy plate 416, and the anodizing treatment tank is provided downstream. 414 is installed. Aluminum alloy plate 416 is conveyed by 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 that does not accumulate an electrolyte 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 fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a primer layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

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

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

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

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

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

<Drying>
After obtaining the support used for the lithographic printing plate precursor according to the present invention by the procedure described above, it is preferable to dry the surface of the support before providing the image recording layer on the support. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 1 second or more, more preferably 2 seconds or more, and preferably 20 seconds or less, 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.

[Image recording layer]
An image recording layer is formed on the support prepared by the procedure described above. As described above, the image recording layer of the lithographic printing plate precursor according to the invention contains (A) an infrared absorbing dye and (B) hydrophobic thermoplastic particles.

(A) Infrared absorbing dye The image recording layer of the present invention contains an infrared absorbing dye. In particular, an infrared absorbing dye having a maximum absorption at 760 to 1200 nm is preferably used. In particular, an infrared absorbing dye which is a dye having an absorption maximum at a wavelength of 760 to 1200 nm is preferably used.

As the infrared absorbing dye, compounds described in paragraph numbers [0058] to [0087] of JP-A-2008-195018 can be used.
Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen ^{atom, -N (R 9) (R} 10), - X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different, and may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. Represents a hydrogen atom, and R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred. X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. . In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom .

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxy groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and charge neutralization is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used in the present invention include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and JP-A No. 2002-023360. Examples thereof include those described in paragraph Nos. [0012] to [0021] of Japanese Patent Publication No. and paragraph Nos. [0012] to [0037] of JP-A No. 2002-040638.

  Moreover, only 1 type may be used for these infrared absorption dyes, and 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, compounds described in JP 2008-195018 A [0072] to [0076] are preferable.

  In the present invention, the content of the sensitizing dye in the image recording layer is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 5.0% by mass, based on the total solid content of the image recording layer. .

(B) Hydrophobic Thermoplastic Particles The image recording layer of the present invention contains hydrophobic thermoplastic particles (also referred to as “hydrophobic thermoplastic polymer particles”). Specific examples of suitable hydrophobic polymers include, for example, polyethylene, poly (vinyl chloride), poly (methyl (meth) acrylate), poly (ethyl (meth) acrylate), poly (vinylidene chloride), poly (meth) acrylonitrile, Poly (vinyl carbazole), polystyrene or copolymers thereof. Polystyrene and poly (meth) acrylonitrile or their derivatives are highly preferred embodiments.
Particularly preferably, the thermoplastic polymer comprises at least 50% by weight polystyrene, more preferably at least 60% by weight polystyrene.
In order to obtain sufficient resistance to organic chemicals such as hydrocarbons used in the cleaner, the thermoplastic polymer is preferably at least 5% by weight, more preferably at least 30% by weight of nitrogen-containing monomer units or higher than 20. It preferably contains monomer units characterized by solubility parameters, for example (meth) acrylonitrile. Such nitrogen-containing monomer units are disclosed in JP-A No. 2002-251005.

  Most preferably, the hydrophobic thermoplastic polymer is a copolymer of styrene and acrylonitrile units in a mass ratio of 1: 1 to 5: 1 (styrene: acrylonitrile), for example a ratio of 2: 1.

  The mass average molecular weight of the hydrophobic thermoplastic polymer particles is preferably in the range of 5,000 to 1,000,000 g / mol. The hydrophobic thermoplastic polymer particles preferably have a number average particle size of less than 200 nm, more preferably 10 to 100 nm. Of the solid content contained in the image recording layer, the amount of the hydrophobic thermoplastic polymer particles is preferably 20% by mass to 65% by mass, more preferably 25% by mass to 55% by mass, and most preferably 30% by mass. It is -45 mass%.

  Hydrophobic thermoplastic polymer particles are preferably present in the image recording layer coating liquid as a dispersion and are prepared by the method disclosed in US 3,476,937. Another preferred method for preparing an aqueous dispersion of thermoplastic polymer particles is to dissolve the hydrophobic thermoplastic polymer in an organic water-immiscible solvent, disperse the resulting solution in water or an aqueous medium, and evaporate the organic polymer. This is a method for removing the solvent.

(Hydrophilic resin)
A hydrophilic resin may be added to the image recording layer of the present invention. Addition of the hydrophilic resin not only improves the developability, but also improves the film strength of the image recording layer itself. As hydrophilic resin, what has hydrophilic groups, such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl, is preferable, for example.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Homopolymers and copolymers of methacrylate, homopolymers and copolymers of hydroxybutyl acrylate Homopolymers of limers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight And copolymers, methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.

  The addition amount of the hydrophilic resin to the image recording layer is preferably 5 to 40% by mass, more preferably 10 to 30% by mass based on the solid content of the image recording layer. Within this range, good developability and film strength can be obtained.

  In the image recording layer of the invention, when the fine particle polymer having the heat-reactive functional group as described above is used, a functional group capable of reacting with the heat-reactive functional group in the fine particle polymer and a protective group thereof The low molecular compound which has can be contained. The addition amount of these compounds is preferably 5% by mass to 40% by mass in the image recording layer, and particularly preferably 5% by mass to 20% by mass. If it is less than this, the crosslinking effect is small and the printing durability is insufficient, and if it is more than this, the developability after aging deteriorates. The compounds usable for these will be described below.

  Such low molecular weight compounds include polymerizable unsaturated groups, hydroxyl groups, carboxyl groups, carboxylate groups, acid anhydride groups, amino groups, epoxy groups, isocyanate groups, and blocked isocyanate groups within the molecule. Can be mentioned. As these compounds, compounds described in JP-A-2003-316021 can be preferably used.

(Other ingredients)
In addition to the above, various compounds may be added to the image recording layer of the present invention as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant in order to make it easy to distinguish between an image area and a non-image area after image formation. 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) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in No. 293247. Further, pigments such as phthalocyanine pigments, azo pigments, and titanium oxide can also be suitably used. The addition amount is preferably 0.01 to 10% by weight based on the total solid content of the image recording layer coating solution. Furthermore, it is preferable to add a coloring or decoloring compound to the image recording layer of the present invention in order to sharpen the image area and the non-image area when exposed. For example, leuco dyes (leucomalachite green, leuco crystal violet, crystal violet lactone, etc.) and pH color-changing dyes (eg ethyl violet, Victoria Poor blue BOH, etc.) together with thermal acid generators such as diazo compounds and diphenyliodonium salts Dyes).

  In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the image recording layer coating solution. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to 5% by mass with respect to the mass of the whole composition.

  If necessary, higher fatty acids such as behenic acid and behenic acid amide or derivatives thereof are added to prevent polymerization inhibition due to oxygen, and are unevenly distributed on the surface of the image recording layer in the drying process after coating. May be. The amount of the higher fatty acid or derivative thereof added is preferably about 0.1 to about 10% by mass based on the solid content of the image recording layer.

  Furthermore, a plasticizer can be added to the image recording layer of the present invention, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

(Formation of image recording layer)
The image recording layer of the present invention is coated by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here 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, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but is generally preferably 0.4 to 5.0 g / m ² . When the coating amount is less than this range, the apparent sensitivity increases, but the film characteristics of the image recording layer that performs the image recording function deteriorate. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

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

(Overcoat layer)
In the lithographic printing plate precursor according to the invention, an overcoat layer can be provided on the image recording layer in order to prevent contamination and scratches by the lipophilic substance on the surface of the image recording layer. The overcoat layer used in the present invention can be easily removed by a hydrophilic printing liquid such as a fountain solution during printing, and contains a resin selected from hydrophilic organic polymer compounds. As the hydrophilic organic polymer compound used here, a film formed by drying has film-forming ability. Specifically, polyvinyl acetate (however, a hydrolysis rate of 65% or more), polyacrylamine salt , Polyacrylic acid copolymer, alkali metal salt or amine salt thereof, polymethacrylic acid, alkali metal salt or amine salt thereof, polymethacrylic acid copolymer, alkali metal salt or amine salt thereof, polyacrylamide, copolymer thereof , Polyhydroxyethyl acrylate, polyvinyl pyrrolidone, copolymer thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, alkali metal salt thereof, or Amine salt, poly-2-acrylamide-2-methyl -1-Propanesulfonic acid copolymer, alkali metal salt or amine salt thereof, gum arabic, fiber derivative (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), modified product thereof, white dextrin, pullulan, enzyme Decomposed etherified dextrin and the like can be mentioned. Further, two or more kinds of these resins can be mixed and used depending on the purpose.

Moreover, you may add the hydrophilic photothermal conversion agent mentioned above to an overcoat layer. Furthermore, in order to ensure the uniformity of coating, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether can be added to the overcoat layer in the case of aqueous solution coating. . The dry coating amount of the overcoat layer is preferably 0.1 to 2.0 g / m ² . Within this range, the developability is not impaired, and the surface of the image recording layer can be satisfactorily prevented from being contaminated or scratched by an oleophilic substance such as a fingerprint adhering stain.

(Image formation and plate making)
The lithographic printing plate precursor of the present invention is image-formed by heat. Specifically, direct image-like recording by a thermal recording head or the like, scanning exposure by an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, or the like is used. Exposure with a solid high-power infrared laser such as a laser or YAG laser is preferred.

  The lithographic printing plate precursor of the present invention on which the image has been recorded is then removed by removing the image recording layer in the non-image area by rubbing the plate surface with a rubbing member in the presence of the treatment liquid (if there is an overcoat layer). The overcoat layer is also removed at the same time.) In the non-image area, the surface of the hydrophilic support is exposed to produce a lithographic printing plate.

  Examples of the rubbing member usable in the present invention include non-woven fabric, cotton cloth, cotton pad, molton, rubber blade, brush and the like.

  As the treatment liquid used in the present invention, a hydrophilic treatment liquid is suitable. For example, water alone or an aqueous solution containing water as a main component is preferable, and in particular, the composition is the same as that of generally known dampening water. An aqueous solution containing an aqueous solution or a surfactant (anionic, nonionic, cationic, etc.) is preferred. Further, the treatment liquid of the present invention may contain an organic solvent. Examples of the solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, Xylene, etc.), halogenated hydrocarbons (trichlene, etc.), and the following polar solvents.

  Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, methyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, Diethylene glycol acetate, diethyl alcohol Rate, etc.), others (triethyl phosphate, tricresyl phosphate and the like).

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the treatment liquid contains a solvent, it is safe and flammable. In view of the above, the concentration of the solvent is preferably less than 40% by weight. As the surfactant used in the treatment liquid of the present invention, either an anionic surfactant or a nonionic surfactant can be suitably used from the viewpoint of foam suppression.

  Examples of anionic surfactants that can be used in the treatment liquid of the present invention include alkyl diphenyl ether disulfonates, alipates, abiates, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, Branched alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkylphenoxy polyoxyethylene propyl sulfonate, polyoxyeletin alkyl sulfophenyl ether salt, sodium N-methyl-N-oleyl taurate, monoamide disodium N-alkyl sulfosuccinate Sulfonate, petroleum sulfonate, sulfated castor oil, sulfated tallow oil), aliphatic alkyl ester sulfate salt, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester, aliphatic monoglyceride sulfate salt, polyoxyethylene alkylphenyl ether sulfate salt, poly Oxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate salt, polyoxyethylene alkyl phenyl ether phosphate ester salt, styrene maleic anhydride copolymer part Saponified compounds, partially saponified compounds of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Particularly preferred among these anionic surfactants are alkyl diphenyl ether sulfonates, dialkyl sulfosuccinates, salts of alkyl sulfates and alkyl naphthalene sulfonates.

  Specific examples of suitable anionic surfactants include sodium dodecylphenoxybenzene disulfonate, sodium salt of alkylated naphthalene sulfonate, disodium methylene dinaphthalene disulfonate, sodium dodecyl benzene sulfonate, dodecyl diphenyl ether dissulfonic acid Examples include sodium, ammonium or potassium perfluoroalkylsulfonate and sodium dioctyl-sulfosuccinate.

  Nonionic surfactants that can be used in the treatment liquid of the present invention include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher Alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. , Fatty acid ester of glycerol of polyhydric alcohol type, fatty acid ester of pentaerythritol, sorbitol and Fatty acid esters of Rubitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines. These nonionic surfactants may be used alone or in admixture of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

  Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the treatment liquid of the present invention preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more. More preferably. Furthermore, the ratio of the nonionic surfactant contained in the treatment liquid is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.

  In addition, an alkaline agent (for example, sodium carbonate, triethanolamine, diethanolamine, sodium hydroxide, silicates) or an acidic agent (for example, citric acid, phosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid) , Oxalic acid, malic acid, tartaric acid, boric acid, amino acids), preservatives (for example, benzoic acid and its derivatives, sodium dehydroacetate, 3-isothiazolone compounds, 2-bromo-2-nitro-1,3-propanediol , 2-pyridinethiol-1-oxide sodium salt, etc.) and other additives (for example, citrate, etc.) can also be used. Although the temperature of a process liquid can be used at arbitrary temperature, Preferably it is 10 to 50 degreeC.

The removal of the image recording layer in the non-image area in the present invention can be preferably carried out by an automatic processor equipped with a processing liquid supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061, JP-A-60-59351, which performs rubbing while conveying an original plate for lithographic printing plate after image recording, Examples include an automatic processor described in US Pat. No. 5,148,746, US Pat. No. 5,568,768, and the like, in which a lithographic printing plate precursor after image recording set on a cylinder is rubbed while rotating the cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. As an example of an automatic processor suitable for the development processing of the present invention shown in FIG. 5, the processing liquid 209 is sent to the spray pipe 204 by the circulation pump 210 and showered, and the rotating brush roll 200 and the plate surface 211 (for lithographic printing plates) are used. An example of an automatic developing processor that supplies the original plate) and rubs the plate surface 12 with the rotating brush roll 200 is illustrated. In the figure, 201 is a receiving roll, 202 is a transport roll, 203 is a transport guide plate, 205 is a conduit, 206 is a filter, 207 is a plate feed table, 208 is a plate discharge table, and 209 is a processing liquid (tank).
In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water and dried.

  The rotating brush roll that can be used can be selected as appropriate in consideration of the difficulty of scratching the image area and the stiffness of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, a metal or plastic in which brush materials are implanted in rows, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100534, or Japanese Utility Model Publication No. 62-167253. A brush roll in which the groove mold material is radially wound around a plastic or metal roll as a core without any gap can be used. The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene can be used. For example, the fiber has a hair diameter of 20 to 400 μm, and a hair length of 5 to 30 mm is preferable. Can be used. Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.

  The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the conveying direction of the planographic printing plate precursor of the present invention, but the automatic processor illustrated in FIG. As described above, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the image recording layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Manufacture of aluminum alloy sheets]
(Examples 1 to 15)
Using an aluminum alloy melt having the composition shown in Table 1 below, an aluminum alloy plate was manufactured by continuous casting with the heat treatment conditions (intermediate annealing) shown in Table 2 below.
Specifically, first, continuous casting was performed using a molten aluminum alloy of each composition 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 then cold-rolled again to obtain a 0.3 mm thickness. Finished to a thickness.
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 molten aluminum alloy used for each.

(Comparative Examples 1-4)
An aluminum alloy plate was manufactured by DC casting without heat treatment using a molten aluminum alloy having the composition shown in Table 1 below.
Specifically, a slab having a thickness of 500 mm was cast by DC casting using a molten aluminum alloy of Al-5.
Next, both sides of the obtained slab were faced by 20 mm, and the heat treatment in the slab state was performed at 500 to 600 ° C. by soaking.
Next, hot rolling was performed to a thickness of 3 mm, an intermediate annealing treatment was performed at 410 to 550 ° C., and then a cold rolling was performed to a thickness of 0.3 mm.
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 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)
First, about the manufactured aluminum alloy plate, 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.
Next, 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 processing 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 result of the particle size distribution, the number of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more was calculated. This calculation was performed by rounding the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.
In the same procedure, the number of intermetallic compounds having an equivalent circle diameter of 1 μm or more was calculated.

In addition, using an X-ray diffractometer, the peak count values of the Al—Fe-based intermetallic compound and α-AlFeSi of each manufactured aluminum alloy plate were measured under the following conditions. As the Al—Fe-based intermetallic compound, the peak count values of Al ₃ Fe and Al ₆ Fe are measured, and the maximum value is the “type of Al—Fe-based intermetallic compound (type of Al—Fe-based)”. As listed in Table 2. The peak angle of Al ₃ Fe is 24.1 °, the peak angle of Al ₆ Fe is 18.0 °, the peak angle of α-AlFeSi is 42.0 °, and the peak count value is This is a value obtained by measuring the diffraction intensity (cps) of the angle. The results are shown in Table 2 below.
X-ray diffractometer RAD-rR (12 kW rotating counter-cathode type, manufactured by Rigaku Corporation)
・ Set tube voltage 50kV
・ Set tube current 200mA
・ Sampling interval 0.01 °
・ Scanning speed 1 ° / min ・ 2θ scanning range 10 ° ～ 70 °
・ Use of graphite monochromator

[Manufacture of support]
Each manufactured aluminum alloy plate was subjected to the following roughening treatment to obtain a support used for a lithographic printing plate precursor.

  As the roughening treatment, the following treatments (a) to (f) 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 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, 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 aluminum alloy plate subjected to the electrolytic surface roughening treatment was 0.05 g / m ² .

(E) Desmutting treatment 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. was sprayed from a spray tube for 5 seconds to perform desmutting treatment.

(F) Anodizing treatment Anodizing treatment was performed using phosphoric acid as the electrolytic solution. The electrolytic solution had a phosphoric acid concentration of 22% by mass and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 1.5 g / m ² .
For the anodized film formed by the above procedure, the average pore diameter (surface average pore diameter) in the surface layer of the anodized film and the average value of the maximum diameter inside the micropore (average value of the maximum diameter in the pore) are as follows: It measured in the procedure of. The results are shown in Table 3.
Surface average pore diameter: An ultra-high resolution SEM (Hitachi S-900) was used to measure the pore diameter in the surface layer of the anodized film. The surface was observed at a magnification of 150,000 times, and an average value was obtained by randomly extracting 50 pores without performing a vapor deposition treatment imparting conductivity at a relatively low acceleration voltage of 12 V. The standard deviation error was ± 10% or less.
Measuring method of the average value of the maximum diameter in the pore: The maximum diameter inside the micropore is the ultra-high resolution of the side surface (commonly referred to as the fracture surface) of the cracked part that occurs when the anodized aluminum alloy plate is bent. A type SEM (Hitachi S-900) was used and observed. The maximum diameter portion inside the micropore on the fracture surface of the anodized film was observed at a magnification of 150,000 times without applying a vapor deposition treatment that imparts conductivity at a relatively low acceleration voltage of 12 V, and 50 pieces The pores were randomized to obtain an average value. The standard deviation error was ± 10% or less.

[Manufacture of lithographic printing plate precursors]
An image recording layer was formed on the support obtained by the above procedure by the following procedure to obtain a lithographic printing plate precursor.

An image forming layer coating solution having the following composition was applied at a thickness of 30 g / m ² and dried.
Hydrophobic thermoplastic polymer particles 2.0g
(Copolymer polymer particles of styrene and acrylonitrile in a molar ratio of 60:40 Average particle diameter after drying: 65 nm)
・ Infrared absorbing dye (I) 0.3g
・ Polyacrylic acid 0.4g
(Glascol D15 manufactured by Allied Colloids)
・ Coloring agent (I) 0.3g
・ Water 97.0g

Infrared absorbing dye (I)

Colorant (I)

The lithographic printing plate precursor thus obtained was exposed with Creo's Trendsetter 3244VFS equipped with a water-cooled 40W infrared semiconductor laser under the conditions of a plate surface energy of 200 mJ / cm ² and a resolution of 2400 dpi, as in FIG. Development processing was performed using an automatic processor having two rotating brush rolls of the above mechanism. The exposure image includes a solid image and a 50% halftone dot chart of a 25 μm dot FM screen. As the rotating brush roll, a brush roll having an outer diameter of 90 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) is used for the first brush roll, and the same direction as the conveying direction is used. 200 rotations per minute (peripheral speed of the brush tip 0.94 m / sec), and the second brush roll was implanted with fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) 60 mm outer diameter The brush roll was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip: 0.63 m / sec). The planographic printing plate precursor was transported at a transport speed of 100 cm / min. The treatment liquid used was the following treatment liquid 1, showered from a spray pipe with a circulation pump, and supplied to the plate surface.

<Processing liquid 1>
To 700 g of deionized water, 77.3 ml of Dowfax 3B2 (Dow Chemical Co., alkyldiphenyl ether disulfonate), 32.6 g of trisodium citrate dihydrate, and 9.8 g of citric acid are added under stirring. Then, deionized water was further added to 1000 g. The pH is about 5.0.

[Evaluation of lithographic printing plate precursor]
The lithographic printing plate precursor obtained by the above procedure was evaluated as follows. The results are shown in Table 4.

(1) Evaluation of printing durability The obtained lithographic printing plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg and printed. The fountain solution used was an aqueous solution to which 4% by volume of IF-102 (Fuji Photo Film Co., Ltd.) was added, and the ink used was TK High Echo SOYMZ Black (Toyo Ink Co., Ltd.). Printing was performed on Tokuhishi art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Evaluate printing durability by assuming the number of copies to be printed when the value measured with a Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material is 5% lower than the measured value for the 100th printed sheet. did. The results are shown in Table 4 (see the following for the indicators of ○, ○ △, Δ, and Δx).
○… More than 50,000 copies ○ △… More than 40,000 copies and less than 50,000 copies △… More than 30,000 copies and less than 40,000 copies Δ ×… Less than 30,000 copies (2) Evaluation of stain resistance The blanket after printing 10,000 copies The dirt was visually confirmed and evaluated according to the following criteria.
○… Blanket is not dirty ○ △… Blanket is slightly dirty but good △… Blanket is in acceptable range △ ×… Blanket is dirty and printed matter is clearly dirty ( 3) Evaluation of micro-corrosion stains The obtained lithographic printing plate precursor was conditioned with interleaf for 1 hour in an environment of 25 ° C. and 70% RH, packaged with aluminum kraft paper, and then heated in an oven set at 60 ° C. Heating was performed for 5 days.
Thereafter, the temperature was lowered to room temperature, and then development processing was performed in the same manner as in the evaluation of printing durability without exposure.
Next, it was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg and printed. The fountain solution used was an aqueous solution to which 4% by volume of IF-102 (manufactured by Fuji Photo Film Co., Ltd.) was added, and the ink used was TK high echo SOYMZ ink (manufactured by Toyo Ink Co., Ltd.). 500 sheets were printed on Tokuhishi art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
The 500th printed product was visually confirmed, and the number of print stains of 20 μm or more per 100 cm ² was calculated. The results are shown in the table.
◎ ... Less than 20 fine corrosion stains (per 80 cm ² )
○ ... 21-50 fine corrosion stains (per 80 cm ² )
○ △ ... 51-80 fine corrosion stains (per 80 cm ² )
Δ: 81 to 100 fine corrosion stains (per 80 cm ² )
△ ×… 101-150 minute corrosion stains (per 80 cm ² )
×… 151 or more micro-corrosion stains (per 80 cm ² )
If the number of stains is 200 or less per 100 cm ² , it can be evaluated as having excellent resistance to severe stains.

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 passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 40 Main electrolytic tank 50 Auxiliary anode tank 200 Rotating brush roll 201 receiving roll 202 transport roll 203 transport guide plate 204 spray pipe 205 pipeline 206 filter 207 plate supply table 208 discharge plate table 209 treatment liquid (tank)
210 circulation pump 211 lithographic printing plate original plate 410 anodizing apparatus 412 feeding tank 413 intermediate tank 414 anodizing tank 416 aluminum alloy plate 418, 426 electrolyte 420 anode 422, 428 pass roller 424 nip roller 430 cathode 434 DC power supply 436, 438 Liquid supply nozzle 440 Shielding plate 442 Drain outlet

Claims (8)

In a lithographic printing plate precursor having an image recording layer containing (A) an infrared absorbing dye and (B) hydrophobic thermoplastic particles on a support,
A lithographic printing plate precursor, wherein the support is prepared using an aluminum alloy plate having a density of an intermetallic compound having a circle-equivalent diameter of 0.2 µm or more on the surface and 35000 pieces / mm ² or more.   The lithographic printing plate precursor as claimed in claim 1, wherein the hydrophobic thermoplastic particles are styrene-acrylonitrile particles. The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the aluminum alloy plate has 2500 / mm ² or less of intermetallic compounds having a circle-equivalent diameter of 1.0 µm or more on the surface.   The peak count value of the Al—Fe-based intermetallic compound of the aluminum alloy plate, measured using an X-ray diffractometer (XRD), is 400 cps or less, and the peak count value of the AlFeSi-based intermetallic compound is 30 cps or less. The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein:   An anodized film having micropores is formed on the surface of the support on the side on which the image recording layer is formed, and the average pore diameter in the surface layer of the anodized film is 10 to 75 nm. The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the average value of the maximum diameter is 1.1 to 3.0 times the average pore diameter.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the anodic oxide film is formed by an anodic oxidation treatment using an electrolytic solution containing sulfuric acid or phosphoric acid.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method.   After performing image recording on the lithographic printing plate precursor according to any one of claims 1 to 7, an automatic processor equipped with a rubbing member rubs the plate surface with the rubbing member in the presence of a processing liquid, thereby A process for producing a lithographic printing plate comprising the step of removing the image recording layer.