JPH02215599A - Substrate for lithographic printing plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a support for a lithographic printing plate. CM Lighting Background] There is a so-called 28 lithographic printing plate in which a photosensitive composition is coated on an aluminum or aluminum alloy (hereinafter referred to as aluminum alloy) plate, but when using aluminum alloy for printing, water retention and photosensitive In order to improve the adhesion with the agent, JP-A-48-45303 and JP-A-57-203 are used.
As described in JP-A-593, JP-A-58-55572, JP-A-61-51896, JP-A-61-233590, and JP-A-62-27191, aluminum alloy After the surface is roughened by one or a combination of mechanical, chemical, and electrochemical methods, a predetermined post-treatment (
Anodizing treatment, etc.) is applied to further improve printing characteristics. Note that this PS plate is usually subjected to exposure, development, correction, and gumming steps to form a lithographic printing plate, which is attached to a printing machine and printed. As an aluminum alloy, for example, JIS^1
Those corresponding to 050, ^1100, and ^3003 are used. In particular, when roughening the aluminum alloy surface by an electrochemical method, that is, AC electrolytic etching treatment,
^1050 equivalent materials with low impurity elements such as Fe, Si%Zn, Cu, Mg, and Mn have good surface treatability, which is an important condition for printing plates, and have good surface roughness after roughening (electrolytic etching bit pattern). ) has been said to be desirable because of its uniformity. However, in recent years, various aluminum composite materials and manufacturing methods have been proposed to reduce the manufacturing cost of 28th edition.
This is not necessarily satisfactory in terms of printing stains and printing durability. Therefore, with the aim of improving the yield strength of aluminum alloys by making them thinner and tougher, various Al-Hg series, ^i'-Mg-S
I-series, f-Hn-series, etc. aluminum has been
42745, JP 58-1048, JP 59-133355, JP 59-22039
5, JP-A-60-63346, JP-A-61
This method has been proposed as shown in Japanese Patent Application Laid-open No. 26746, Japanese Patent Application Laid-Open No. 63-30294, etc. However, compared to the conventional ^1050 material, these proposed aluminum alloys have greatly improved the yield strength and fatigue strength of the aluminum alloy to [11], and have improved bending resistance during handling and plate elongation resistance during printing. Although improvements in properties and thinning can be obtained, the electrolytically etched bit pattern tends to be non-uniform, and there are problems such as printing stains, which deteriorate printing properties. Furthermore, as proposed in Japanese Patent Publication No. 61-60798, etc., a predetermined post-treatment is applied to the outer surface of a composite material made by laminating and bonding an aluminum sheet of about 20 to 80 μm, paper, and thermoplastic resin together. There are also cases where it is being strained. In this case as well, ■ The uniformity of the rough surface and the adhesive interface of the composite material are adversely affected by normal wet surface treatment, so it is necessary to take measures such as anodizing with special equipment, and ■ Lack of printing durability in the printing field, which requires printing durability of around 100 sheets or more; ■Despite the purpose of saving aluminum resources, the cost of paper or organic resin, adhesive bonding, and compounding process is high. It is large, has little cost advantage, and also has the disadvantages of 1. The adhesive surface of the composite material peels off easily. In addition, with anodizing treatment, which is a conventional post-processing method, when manufacturing lithographic printing plate materials that can be printed on both sides, there are two issues: (1) increased manufacturing costs due to equipment modification or new installation, and (2) increased plate width of aluminum alloy materials during processing. , it is difficult to produce a uniform anodic oxide film on both sides due to current distribution, etc.
■Surface defects such as scratches are likely to occur on the back side of aluminum alloy materials due to foreign objects attached to process rolls, etc.
■Bubble pools of dissolved reaction gas (112 gas, etc.) during anodization are formed on the back side of aluminum alloy materials, making the treated surface uneven. If heated after surface treatment, cracks will occur in the film, causing printing stains, etc. It has the disadvantage that it can cause In addition, as clearly disclosed in JP-A No. 62-196190, conventional surface roughening methods such as pole grain, wire grain, brush dale, liquid honing, etc., and electrochemical roughening are available. Surface roughening, chemical roughening, and the above-mentioned composite roughening, etc., have a negative impact on quality stability (printing stains, printing durability).
, productivity, and manufacturing cost are not always satisfied.

[Disclosure of the invention]

As a result of intensive research into the above-mentioned problems, the present inventors have discovered that a lithographic printing plate obtained by subjecting both sides of an aluminum alloy to a roughened surface using a predetermined roughening method and subjected to a hydration oxidation treatment. When we investigated the characteristics of the support, we realized that when a hydrated oxide film was applied, the surface treatment properties and economic efficiency were superior to those for lithographic printing plates that were provided with an anodized oxide film, and we decided to investigate further. As a result of adding the It has been found that the ink is irreversibly adsorbed to the defective areas of the ink, and spots of ink stains are likely to occur in the non-image area. The present invention has been made based on the above findings, and provides a hydrated oxide film having a coating weight of approximately 0.4 to 0.8 g/m'' and having micro pits with an opening diameter of approximately 0.05 to 0.2 μm. The present invention provides a support for a lithographic printing plate, which is formed by heating and tempering an aluminum alloy plate provided with the following: .4~0.8μst, maximum roughness (R
max) is approximately 3 to 8 μm1 1 μm from the center line of the roughness curve
The number of peaks that intersect with the lower line is approximately 50 to 85 72.5 mm
An opening diameter of approximately 0 is placed on the surface of a rough aluminum alloy plate.
．． Adhesion amount approximately 0 with micro pits of 0.05 to 0.2 μm
．． A hydrated oxide film of 4 to 0.8 g/*" is provided, and this is heated and tempered, and furthermore, a thickness of about 50 to 30 g/*" is provided.
At least one side of a cold-rolled aluminum alloy plate having a diameter of 0.071 m was shot blasted using a substantially spherical blasting material at a predetermined blasting speed and blasting density to give a center line average roughness (Ra) of about 0.4 to 0.07 mm. 8. czm, the maximum roughness (Rmax) is approximately 3 to 8 μm, and the number of peaks that intersect with the line 1 μm below the center line of the roughness curve is approximately 50 to 85. It is preferable that a hydrated oxide film with a deposited amount of about 0.4 to 0.8 g/m2 containing micro pits with an opening diameter of about 0.05 to 0.0, ZJiyb is formed, and this is heated and tempered. By the way, in the support for planographic printing plates, aluminum alloy plates are usually made of material ^1050 or ^11.
00 equivalent material is used, and the tempering is set to the old 8.1116. Further, a plate having a thickness of about 240 to 300 μm is used. In this case, there is no problem in terms of flatness with electrochemical roughening, but the aluminum alloy plate is easily deformed and distorted during shot blasting, which impedes the dimensional stability of the support and causes problems. There is. However, according to the present invention, even aluminum alloy plates with a thickness of 50 to 300 μm can be processed without impairing dimensional stability.
It has good flatness, which makes the aluminum alloy plate suitable for printing, and at the same time there is no distortion or deformation during surface treatment. That is, the cold-rolled aluminum alloy plate used in the present invention refers to a sheet that has not been subjected to temper annealing, which is usually performed after cold rolling, and is referred to as temper H1n. As for this aluminum alloy plate, in addition to pure aluminum type,
Aluminum-magnesium alloy, aluminum-manganese alloy, etc. can be used. and ■The yield strength of the support after heat treatment is 18Kg/a-
``With the above results, ■ Strain resistance during shot blasting is good, ■ Wrinkles do not easily appear in the aluminum alloy plate during continuous hydration oxidation treatment, ■ Defects do not easily appear in the hydrated oxide film, ■
From the viewpoint of good thermal refining properties, it is not preferable for the plate thickness to be less than 50 μm, and if it exceeds 300 μm, the cost tends to be high, so the plate thickness should be approximately 50 to 300 μm.
Brass is preferred. In addition, the alloy materials used include approximately 1.5 to 3.0% by weight of M, approximately 0.1% by weight or less of Si, and approximately 0.3% by weight of Fe.
Below, Cu is about 0.05% by weight or less, Zn is about 0.05%
Weight% or less and Cu+Zn is about 0.03 to 0.06
% by weight, and the balance is preferably about 0.1% by weight or less of unavoidable impurities and Al. For example, if the H content is too high (more than 3% by weight), defects are likely to occur in the hydrated oxide film; if the Ng content is too low (less than 1.5% by weight), the yield strength of the support is 18 kg/a.
m" or more, and the amount of Cu added is 0.
If the content is outside the range of 0.03 to 0.06% by weight, film defects tend to occur. Shot blasting of aluminum alloy plates erases the rolling streaks on the surface of the rolled plate to make the surface equal force, and also increases the surface area by densely providing a large number of unevenness, which combines with the hydrated oxide film formed in the subsequent process. This improves the adhesion with the photosensitizer. This roughening is based on the centerline average roughness (Ra> of approximately 0.4 to 0.8.tzm, maximum roughness (Rmax) of approximately 3 to 8μ, and the centerline of the roughness curve specified in JIS 80601). from 1
The number of peaks that intersect with the line under μ steel is approximately 50 to 85/2.5
It is desirable to perform this so that the aluminum alloy has an n+m rough surface. That is, if Ra is too small, less than 0.64 μm, the effect of improving adhesion is small, and if it is too large, exceeding 0.8 μm, the density of the peaks will inevitably become smaller, and the adhesion will tend to deteriorate. by. In addition, if Rmax is too small, less than 3 μm, shot blasting is insufficient and there are untreated areas on the surface.
This is because adhesion becomes insufficient, and conversely, if it is too large, exceeding 8 microns, local unevenness increases, which tends to increase printing stains. The number of peaks is determined by obtaining a roughness curve according to JIS B12O3.
The number of peaks that intersect with a line drawn 1 μm below the center line is calculated, and the number is calculated per length of 2.51. If the number of ridges is too small (less than 50), the adhesion will decrease,
When the number exceeds 85, local unevenness increases, which tends to increase printing stains. Shot blasting conditions cannot be unambiguously determined as they vary depending on the material thickness and tempering conditions, but the shape of the shot material is spherical.
It is desirable that the film be in the form of a hydration oxidation process (hard to form film defects), which will be described later. As a spherical projectile material, mesh approx. #60 to #1so (
In addition to being made of cast iron with a grain size of approximately 100 to 200 μmφ),
Ceramic beads (zirconia, etc.), engineering plastic beads, etc. can be used, but cast iron, which has a large specific gravity, is preferable from the viewpoint of the cost of the shot material, recovery loss of the shot material, and frictional deformation of the shot material. In addition, due to its spherical shape, equipment (projection nozzle,
There is less wear and tear on parts (such as impellers, etc.), making it possible to significantly reduce the cost of shot blasting, and
Compared to regular steel grids and reduced iron powder, it has a thicker oxide film and is less susceptible to oxidation, so there is less risk of dust explosion. In addition, as proposed in Japanese Patent Application Laid-Open No. 196190/1983, the radius of curvature of the tip of the projectile is not an acute angle of 20 Im or less, so it does not stick to the aluminum alloy plate.
<, printing stains are less likely to occur. For example, in the case of one-impeller type, the projection conditions are as follows:
Projection speed is usually 5-20m+/sec, preferably about 10-20m+/sec.
151 seconds, the projection density is 100 to 400 KH/m'', particularly preferably about 200 g/s''. In addition, in order to improve the shot blasting property (isotropy of the rough surface), the center line average roughness (Ra) of the surface of the cold rolled sheet before roughening is preferably about 0.2μ or less. is 0.12μ
It is desirable to keep it below m. In order to make Ra 0.12 μm or less, for example, the surface of a rolled aluminum alloy material is subjected to MF finishing (+ail! finish), which has been used in the production of conventional materials, in the final step of cold rolling to reduce the Ra. is about 0.2 to 0.
Instead of using a 5-μm wire, we use a gloss roll to reduce the Ra to about 0.12 μm or less using a BF finish (Bright fi
nish) or LF finish (Luster fini)
sh) can be considered. Shot plus! After roughening the surface, the shot material is removed by known chemical etching, etc., washed with water, and then subjected to hydration oxidation treatment to give the rough surface an opening diameter of approximately 0.05 to 0.2.
Approximately 0.4 to 0.8 g of adhesion with μm micro pits
/m" oxide film. Hydrated oxide film is formed by treatment with an aqueous solution of p115-11, for example, boehmite-based film obtained by immersion in boiling pure water of pH 6-8, boric acid. A boehmite-based film obtained by immersion in a pure water solution whose pH has been adjusted to about 5 to 6 with a weak acidic substance such as, and a pure water solution whose pH has been adjusted to about 18 to 11 with a basic substance such as ammonia and caustic soda. There are boehmite films etc. obtained by immersion.If the pH is higher than 11, the defects in the intermetallic compound and the hydrated oxide film around it become deep and large, making it easier for ink stains to occur. On the other hand, when the pH is lower than 5, the film formation rate decreases and the productivity decreases.Additionally, when hypohalite, peroxopate, etc. are added to the treatment solution, the micropits become denser. The adhesion with the photosensitizer is further improved. Also, if the thickness of the hydrated oxide film is too thin, the effect of improving adhesion with the photosensitizer and printing durability will be small; conversely, if it is too thick, the hydration Since defects in the oxide film tended to increase and printing stains increased, it was important that the thickness of the hydrated oxide film was about 0.4 to 0.8 g/m''. In addition, in order to improve the adhesion of the hydrated oxide film to the photosensitizer and the printing durability, a silicon compound may be added, and examples of the silicate solution used in this case include water glass, water glass, etc.
Aqueous solutions or suspensions of sodium silicate, potassium silicate, silica sol, etc. can be used, and the concentration of silicate is usually in the range of 0.5 to 10%, particularly 0.5 to 5%. This is desirable. The silicon compound interposed in the hydrated oxide film with such a silicate-containing solution is approximately 0.0 in terms of silicon.
It is desirable that the amount is 1-0.15 g/+*". In other words, if the amount of silicon compound interposed in the hydrated oxide film is too small, the effect of improving the adhesion with the photosensitizer will be small. On the other hand, if there are too many silicon compound particles, the silicon compound particles will be present unevenly on the surface of the hydrated oxide film.
This is because the adhesion with the photosensitizer tends to decrease. When a phosphorus compound is interposed on the surface of the above-mentioned hydrated oxide film, the adhesion to the photosensitive agent and the corrosion resistance of the non-image area are greatly improved. This can be easily achieved by treating with an aqueous solution containing a phosphorous compound and drying, e.g.
A phosphorus compound prepared by dissolving a phosphorus compound in water such as deionized water, tap water, or industrial water to a concentration of 0 pp+s or more, preferably about 1 to 20%, and adjusting the pH to 2 to 12, preferably 6 to 8. Using an aqueous solution of the compound, the temperature lO~1
It can be easily formed by dipping, coating, or spraying at 00° C. for 1 second to 10 minutes, preferably for about 5 to 20 seconds. The pH of this aqueous solution was adjusted by adding 0% to phosphoric acid, citric acid, acetic acid, and Ni0H1, taking into account the plI of phosphorus compounds.
, Cm (OHL, l-liethanolamine, ammonia, etc.).The phosphorus compound interposed on the hydrated oxide film by treatment with a solution containing the phosphorus compound is From the viewpoint of corrosion resistance and paint film adhesion, it was desirable that the phosphorus content be approximately 0.00 to 0.15 g/m'' in terms of phosphorus. Water-soluble inorganic phosphates such as phosphate, birophosphate, metaphosphite, hypophosphate, orthophosphate, metaphosphate, l-ribolyphosphate, tetrapolyphosphate, and birophosphate One or more types of salts can be used. When processing with a phosphorus compound solution, a small amount of surfactant, for example 0.1 to 2%, is added to this solution. In other words, if the hydrated oxide film contains not only a phosphorus compound but also a surfactant,
It has been found that the adhesion of the phosphorus compound to the hydrated oxide film is improved, making it even more desirable. As the nonionic surfactant, for example, one or two types of polyoxyethylene alkyl allyl ether type (polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether), alkyl ether type (polyoxyethylene lauryl ether), etc. More than one species can be used. Further, any of a silicon compound, a phosphorus compound, and a nonionic surfactant may be present. In addition, in order to simultaneously satisfy the reduction of printing stains and the printing durability, it is extremely preferable to use a combination of the shot blasting rough surface using the spherical projection material and the formation of the above-mentioned hydrated oxide film.
In other words, when the rough surface of a spherical shot material is subjected to hydration oxidation treatment, there are fewer film defects of 5 to 10μ diameter formed after hydration oxidation treatment, and even if there are film defects, these defects are small. This is because the substances contained in the above-mentioned photosensitive agent are difficult to adsorb, making it difficult for ink to aggregate in the area during printing. In addition, the printing durability is 0.05 to 062, which the hydrated oxide film has.
It is excellent due to the anchoring effect of the micro pits of μ and φ. However, for example, if the rough surface of a spherical projection material is coated with the same amount of conventional anodic oxide film, although printing stains are good, printing durability is poor. Through the above surface treatment, a large number of micro pits are formed by a hydrated oxide film on the surface with mechanically applied approximately hemispherical irregularities, and a surface with good adhesion to the photosensitive agent is obtained. In the present invention, a rolled plate is heated to impart desired properties to the aluminum alloy plate. In other words, this heating has a yield strength of Il? The plate is tempered and softened to a thickness of 117 am' or more to improve fatigue resistance, and the distortion and deformation caused during mechanical roughening treatment is removed to create a homogeneous and flat plate. Furthermore, the purpose is to further improve the adhesion between the aluminum alloy plate and the hydrated oxide film by heating. Heating is performed at an ambient temperature of 150 to 360°C and a heating time of 3 to 2
It can be carried out within the range of 0 hours, and the temperature should be set at 400 to 60
It is also possible to heat it for a short time at 0°C. By adjusting these heating conditions, it is possible to obtain a plate with desired characteristics depending on the application, such as heat-treated H24, 1122, or H34 material in the state after heating. By subjecting the surface to roughening treatment, the degree of distortion and deformation is smaller than in the past, so it becomes possible to remove them within conditions suitable for this thermal refining. A conventionally known photosensitive layer can be provided on the lithographic printing plate support thus obtained to obtain a photosensitive lithographic printing plate. The plate has excellent performance.8 The photosensitive agent (photosensitive substance) applied to the aluminum alloy plate is not particularly limited, and generally known ones can be used, such as hydrophilic polymers and Compositions consisting of diazonium salts, compositions of quinone diazide compounds and alkali-soluble resins, polymers whose elliptic components are unsaturated carboxylic acids such as cinnamic acid and phenylene diacrylic acid that undergo dilation upon irradiation with actinic rays, active Examples include a composition of a binder polymer and a compound that undergoes a polymerization reaction upon irradiation with light, or an azide-based photosensitive composition. A photosensitive lithographic printing plate can be obtained by dissolving these photosensitizers together with various well-known additives in an appropriate solvent, applying the solution to the aluminum alloy plate of the present invention, and drying the solution. If a copy is placed on this photosensitive lithographic printing plate and exposed and developed according to a conventional method, it will have excellent hydrophilicity and water retention, and extremely high adhesion between the image area made of the photosensitive agent and the aluminum alloy plate. A printing plate with excellent printing durability can be obtained. The aluminum alloy lithographic printing plate of the present invention is
■Compared to conventional products, there is no printing stain in non-image areas, 0 surface treatment is low cost, and double-sided printability is good. ■Printing using thinner toughening material improves material strength. There are no problems with printing characteristics such as stains, and material costs can be reduced.

[Example 1] Center line average roughness Ra is 0.12 μm, Mg is 1.6% by weight, Fe is 0.251fi%, Si is 0.1% by weight,
Cu content is 0.03fi amount%, Zn content is 0.03fi amount%. An aluminum alloy plate (thickness 200 μm, tempering: HI3) containing 1% by weight of O and 0.1% by weight or less of other avoidable impurity elements was made into a spherical projection material 5B-2 (cast iron, #80 to #1OO1 Shinto Kogyo). Co., Ltd.) by shot blasting (projection speed 13 m/sec)
The surface was grained at a projection density of 200 g/m2N. The maximum surface roughness (Rmax) at this time is 5.4 μm, and the center line average roughness Ra is 0.6 μm 1 from the center line of the roughness curve.
The number of peaks intersecting the line below μm was 60/2.5 mm. This aluminum alloy plate was degreased, washed with water, and then etched in a 10% caustic soda aqueous solution. After washing with water, it was neutralized in a 30% aqueous nitric acid solution and thoroughly washed with water. Then, it was immersed in a sodium hypochlorite aqueous solution (NaOC1 concentration: 200 ppp, pH: 1 G, o) at a temperature of about 90 ° C. to form micro pits with an opening diameter of about 0.05 to 0.2 μm, A hydrated oxide film with a thickness of about 0.6 g/m' is formed. Next, in a No. 3 water glass solution with a concentration of 1.5% (pH 11,
4) at a temperature of about 85°C, and then through a spray water washing process, the surface of the aluminum alloy material is coated with about 0% silicon in terms of silicon.
．． 035 g/+m'' of silicon compound is provided. After the silicon compound is deposited, the concentration is 15 at a temperature of 25-30°C.
% sodium tripolyphosphate aqueous solution was applied and dried with hot air at 150°C for 10 minutes to interpose inorganic phosphate in an amount of about 0.03 g/intestine in terms of phosphorus on the surface of the hydrated oxide film treated with water glass. Thereafter, the aluminum alloy plate is heated in an atmospheric furnace at an ambient temperature of 200°C, and the aluminum alloy plate is made into a material equivalent to ■21 material (yield strength: 22 kg/mm).
). A predetermined photosensitive agent was coated on the surface of the support thus treated so that the coating weight after drying was 2 g/m' to form a photosensitive layer. Then, this photosensitive lithographic printing plate was subjected to predetermined exposure and development treatments, and the resulting printing plate was printed using an offset printing machine.

[Example 2] The same procedure as in Example 1 was carried out except that no silicon compound or phosphorus compound was used.

Example 31 The same procedure as in Example 1 was carried out except that the phosphate aqueous solution treatment was omitted and no phosphorus compound was attached. [Example 4] In Example 1, the aluminum alloy material was finished rolled with a glossy roll in the final step of the cold rolling process to obtain an aluminum alloy plate with an Ra of 0.03 μm, and the projection during shot blasting was performed. Gem density to 150
Everything was done in the same way except for.

[Comparative Example 1] The same procedure as in Example rIA1 was carried out except that the aluminum alloy plate was not heated and tempered after surface treatment.

[Comparative Example 2] In Example M3, anodic oxide film 1ii (film amount o, sg/-
Everything else was done in the same way, except for the difference.

[Comparative Example 3] The same procedure as in Example 1 was carried out except that the hydration oxidation degree film thickness was changed to 0.9 g/m''. [Comparative Example 4] In Example 1, the Eiwa oxide film thickness was changed to O, Zg/la'
It was done in exactly the same way except that.

[Comparative Example 5] In Example 1, the micro pit diameter of the hydrated oxide film was 0.
．． The process was carried out in exactly the same manner except that the thickness was 0.04 μm.

[Comparative Example 61 In Example 1, the micropit diameter of the heptahydrate oxide film was 0.
．． The process was carried out in exactly the same manner except that the 3μ floor was used. [Characteristics] The table below shows the results of examining the staining and printing durability of the non-image areas of the printing plates obtained on each side above.

Claims (10)

[Claims] (1) An aluminum or aluminum alloy plate provided with a hydrated oxide film with a coating weight of approximately 0.4 to 0.8 g/m^2 and having micro pits with an opening diameter of approximately 0.05 to 0.2 μm is heated and tempered. A support for a lithographic printing plate, characterized in that: (2) In the lithographic printing plate support according to claim 1, the centerline average roughness (Ra) is about 0.4 to 0.8.
μm, the maximum roughness (Rmax) is approximately 3 to 8 μm, and the number of peaks that intersect with the line 1 μm below the center line of the roughness curve is approximately 50 to
85 pieces/Aperture diameter approximately 0.05 to 0.2μ on the surface of a 2.5mm roughened aluminum or aluminum alloy plate.
Deposition amount approximately 0.4 to 0.8 g/m with micro pits
A hydrated oxide film of m^2 is provided, and this is heated and tempered. (3) In the support for a lithographic printing plate according to claim 1 or 2, at least one surface of a cold-rolled aluminum or aluminum alloy plate having a thickness of about 50 to 300 μm has a substantially spherical projection material. The center line average roughness (Ra) is approximately 0.4 to 0.8 μm, the maximum roughness (Rmax) is approximately 3 to 8 μm, and the roughness curve intersects with the line 1 μm below the center line. The number of mountains is about 50-85/2.
The rough surface is 5 mm, and the rough surface has an opening diameter of approximately 0.05 to 0.
．． The adhesion amount is approximately 0.4-0.2 μm with micro pits of 2 μm.
A hydrated oxide film of 8g/m^2 is formed and this is heated and tempered. (4) A lithographic printing plate support according to claims 1 to 3, wherein the hydrated oxide film is treated with an aqueous solution having a pH of about 5 to 11. (5) In the support for a lithographic printing plate according to claims 1 to 4, a silicon compound is present in the hydrated oxide film.
About 0.01 to 0.15 g/m^2 in terms of conversion. (6) In the support for a lithographic printing plate according to claims 1 to 4, a phosphorus compound is present in the hydrated oxide film at about 0.005 to 0.15 g/m^2 in terms of P. What you have. (7) In the lithographic printing plate support according to claims 1 to 3, the aluminum alloy contains about 1.5 Mg
~3.0% by weight, Si about 0.1% by weight or less, Fe about 0.
3% by weight or less, Cu about 0.05% by weight or less, Zn about 0.
0.05% by weight or less, and Cu+Zn is about 0.03 to 0.05% by weight or less.
0.6% by weight, and the remainder is about 0.1% by weight of unavoidable impurities.
Consists of the following and Al. (8) In the lithographic printing plate support according to claims 1 to 3, the yield strength of the aluminum or aluminum alloy plate after heat treatment is about 18 kg/mm^2 or more. (9) In the support for a lithographic printing plate according to claim 2 or 3, the center line average roughness (Ra) is about 0.
4-0.8μm, maximum roughness (Rmax) about 3-8μm
, the center line average roughness (Ra) of the surface of the cold rolled plate before it becomes a rough surface with the number of peaks intersecting the line 1 μm below the center line of the roughness curve being approximately 50 to 85/2.5 mm. is approximately 0.2 μm or less. (10) The support for a lithographic printing plate according to claim 3, in which the blasting material is made of cast iron with a mesh size of #60 to #150.