JPH0892679A - Aluminum alloy substrate for planographic printing plate - Google Patents

Abstract

PURPOSE: To improve the performance of a printing plate by allowing particles each having a specified particle diameter to account for a specified percentage of the amt. of all intermetallic compds. contained in an Al alloy plate having a specified compsn. CONSTITUTION: The compsn. of an Al alloy plate is composed of >0 to 0.20wt.% Fe, <=0.13wt.% Si, >=99.7wt.% Al and the balance inevitable impurities and particles each having <0.1μm particle diameter are allowed to account for >=0.5wt.% of the amt. of all intermetallic compds. contained in the Al alloy plate. The objective Al alloy substrate is formed using the resultant Al alloy plate. When the Al alloy plate contains <0.05wt.% Ti and <0.05wt.% Cu, the cost of materials can be reduced and the Al alloy substrate is excellent in suitability to surface roughening by electrolysis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy support used for a lithographic printing plate and a method for producing the same, and particularly to an aluminum alloy support for a lithographic printing plate suitable for electrochemical graining treatment and a method for producing the same. It is about.

[0002]

2. Description of the Related Art Aluminum plates (including aluminum alloy plates) are used as aluminum supports for printing plates, especially as supports for offset printing plates. Generally, in order to use an aluminum plate as a support for an offset printing plate, it is necessary to have appropriate adhesiveness to a photosensitive material and water retention.

For this purpose, the surface of the aluminum plate must be roughened so as to have a uniform and fine grain. This roughening treatment has a significant influence on the printing performance and printing durability of the plate material when offset printing is actually carried out after plate making, and therefore its quality is an important factor in the plate material production. As a roughening method of the aluminum support for printing plates, AC electrolytic etching method is generally adopted,
As the current, a normal sine wave alternating current or a special alternating waveform current such as a rectangular wave is used. Then, the surface of the aluminum plate is roughened by an alternating current using an appropriate electrode such as graphite as a counter electrode, which is usually performed in a single treatment, but the pit depth obtained there is generally shallow. The printing durability was inferior. Therefore, various methods have been proposed in order to obtain an aluminum plate suitable as a printing plate support having a grain in which pits having a depth deeper than its diameter are present uniformly and densely. As a method thereof, a surface roughening method using a special electrolysis power source waveform (Japanese Patent Laid-Open No. Sho 5)
3-67507), the ratio of the amount of electricity at the time of the anode and the cathode at the time of electrolytic surface roughening using an alternating current (Japanese Patent Laid-Open No. 54-6560).
No. 7), a power supply waveform (JP-A-55-25381), and an energization amount per unit area (JP-A-56).
No. 29699) is known.

Also known is a combination with mechanical surface roughening (Japanese Patent Laid-Open No. 55-142695).
On the other hand, as a method of manufacturing an aluminum support, a slab (thickness 400
~ 600 mm, width 1000-2000 mm, length 200
(0 to 6000 mm) is cast, and the surface of the slab surface is subjected to a chamfering machine to cut into 3 to 10 mm by the chamfering machine. After that, in a soaking furnace to remove stress inside the slab and homogenize the structure A soaking treatment step of holding at 480 to 540 ° C. for 6 to 12 hours is performed, and then hot rolling is performed for 4 hours.
Perform at 80-540 ° C. After hot rolling to a thickness of 5 to 40 mm, cold rolling is performed to a predetermined thickness at room temperature. Further, after that, annealing is performed to homogenize the structure to homogenize the rolled structure and the like, and then cold rolling is performed to a prescribed thickness to correct the plate so as to have a good flatness. The aluminum support thus prepared was used as a support for a lithographic printing plate.

However, in the case of electrolytic surface-roughening treatment, it is particularly susceptible to the influence of the aluminum support as a target,
When manufacturing the aluminum support through the process of melting and holding → casting → chamfering → soaking, heating and cooling are repeated,
Even if there is a step of scraping off the surface layer called surface grinding, variations in metal alloy components and the like occur in the surface layer, which causes a reduction in the yield as a lithographic printing plate.

On the other hand, the applicant of the present invention first reduced the variation in the material of the aluminum support and improved the yield of the electrolytic surface roughening treatment to obtain a lithographic printing plate of excellent quality and good yield. As a method that can be made, after casting from an aluminum melt and hot rolling continuously to form a thin plate hot rolling coil, cold rolling, heat treatment, straightening the aluminum support to roughen it A method for producing a support for a lithographic printing plate characterized by the following is proposed (JP-A-3-79).
798 publication).

[0007] In addition, in order to obtain a good electrolytic graining aptitude in JP-A 6-48058 discloses, Fe: 0.4
~ 0.2 wt%, Si: 0.2-0.05 wt%, C
u: 0.02% by weight or less, aluminum 99.5% by weight
It is proposed that continuous casting is performed from the above molten aluminum and that 20 to 90% of the Fe content is present in the crystal grain boundaries.

Further, examples of inventions defining the alloy components of the support are disclosed in JP-A-62-146694 and JP-A-60-2.
30951, JP 60-215725 A, JP 6 A
Nos. 1-26746 and 58-8635 are disclosed. Further, the present applicants have proposed, as a method for simplifying raw materials and producing a support for a lithographic printing plate at low cost, Japanese Patent Application Nos. 5-249699 and 6-71.
No. 264 proposes the method described in each specification. In addition to that, Japanese Patent Application No. 5-307108 discloses an aluminum alloy base material which is directly cast and rolled directly from a molten aluminum into a plate shape in order to obtain a good electrolytic grain shape, and is subjected to cold rolling, heat treatment and straightening as appropriate. Proposes an aluminum alloy base material for a lithographic printing plate, characterized in that the number and size of intermetallic compounds are kept within a predetermined range.

[0009]

However, also in the manufacturing method described in Japanese Patent Laid-Open No. 6-48058, which has been proposed above, the rate of electrolytic surface roughening treatment and the suitability for surface roughening depend on the components of the aluminum alloy support. There was variation. The object of the present invention is to reduce the variation in the material of the aluminum alloy support, improve the yield of the electrolytic surface roughening treatment,
It is an object of the present invention to provide an aluminum alloy support for a lithographic printing plate, which is excellent in roughening suitability and which can produce a low cost lithographic printing plate, and a method for producing the same.

[0010]

[Means and Actions for Solving the Problem] The inventors of the present invention have earnestly studied the relationship between the aluminum alloy support and the electrolytic surface roughening treatment, and as a result, the raw material cost was reduced and the surface roughening suitability was varied. In order to prevent pitting, it is important that the shape of the pits generated during electrolytic surface roughening is stable, and in particular that the edge portions of the pits do not collapse. The inventors of the present invention have found out that the presence of a fine intermetallic compound is sufficient to find the present invention.

That is, the above object of the present invention is to provide an aluminum alloy plate having 0 <Fe ≦ 0.20% by weight, 0 ≦ Si ≦ 0.13% by weight, Al ≧ 99.7% by weight, and the balance being inevitable impurity elements. Among the intermetallic compounds contained in the aluminum alloy plate, the particle size is 0.1.
0.5% or less of all intermetallic compounds by weight of μm or less
An aluminum alloy support for a lithographic printing plate, wherein the aluminum alloy support is 0 ≦ Ti <0.05
This is achieved by the aluminum alloy support for a lithographic printing plate as described in the above item, characterized in that it contains 0% by weight and 0 ≦ Cu <0.05% by weight.

In the present invention, from the molten aluminum,
For example, as a method of producing an aluminum ingot using a fixed mold, a casting technique such as a DC method has been put into practical use. As a continuous casting method using a driving mold, a method using a cooling belt such as the Hazley method or a method using a cooling roll such as the Hunter method or the 3C method can be used. Further, JP-A-60-238001, JP-A-60-240360 and the like disclose methods for producing a thin plate coil.

In order to obtain excellent properties as an aluminum alloy support for a lithographic printing plate, the present invention has a very fine particle size among the above alloy composition ranges and the intermetallic compounds contained in the aluminum alloy plate. By making the existence of such materials, the raw materials can be simplified and excellent electrolytic roughening suitability can be obtained. The intermetallic compound is a compound (for example, FeAl ₃ , FeAl ₆ , α-Al) that does not form a solid solution in aluminum among alloy components in aluminum.
(FeSi, TiAl ₃ , CuAl _2, etc.) refers to those crystallized in a eutectic form in an aluminum alloy. (From “Fundamental and Industrial Technology of Aluminum Materials”, published by Japan Light Metal Association, page 32, etc.) In the present invention, the particle size of the intermetallic compound is 0.
The proportion of particles having a size of 1 μm or less is preferably 0.5% or more, more preferably 1% or more, and further preferably 2% or more of the total intermetallic compound. The upper limit is preferably 10% or less.

As a method for measuring the particle size of the intermetallic compound, an aluminum alloy plate is dissolved in hot phenol, subjected to a solidification preventing treatment, and then filtered and extracted with a filter having a predetermined pore size, or a dissolved solution. Alternatively, a method is used in which an intermetallic compound as a solid content is separated from a filtrate by a centrifuge and a diameter is measured by observation with a scanning electron microscope (SEM). Further, the total amount of the intermetallic compound is measured by measuring the weight (a) of the residue filtered and extracted with a filter having a predetermined pore size, and further using the centrifuge or the vacuum distillation method for the intermetallic compound passing through the filter. The weight (b) is separated and measured, and it is determined from the total of the weight (a) and the weight (b).

In the present invention, the Fe component is 0 <
Fe ≦ 0.20% by weight, preferably 0.05 ≦ F
e ≦ 0.19% by weight, particularly preferably 0.08 ≦
Fe ≦ 0.18% by weight. In the present invention, the Si component is 0 ≦ Si ≦ 0.13% by weight, preferably 0.02 ≦ Si ≦ 0.12% by weight, and particularly preferably 0.025 ≦ Si ≦ 0.10% by weight. is there.

In the present invention, as the Cu component, 0 ≦ C
u <0.05% by weight, preferably 0.001 ≦ Cu <
0.008% by weight, as Ti component 0 ≦ Ti <0.0
5% by weight, preferably 0 ≦ Ti <0.03% by weight. In general, Ti is added as a grain refiner, and Cu is added to control the grain pit shape.

For Al ≧ 99.7% by weight, Al ≧ 9
By setting it as 9.7% by weight, it is possible to use an Al ≧ 99.7% by weight ingot material that is inexpensively distributed in the general market, and it is effective in reducing the cost of raw materials. Further, in order to prevent the grain shape from becoming distorted, the upper limit is preferably less than 99.99% by weight.

Other unavoidable impurities (eg Mg, M
(n, Cr, Zr, V, Zn, Be, etc.) has a small content, and thus does not particularly affect the surface treatment property and the stain resistance.
As a raw material of the Fe component, a commercially available Al having an Fe content of 50% is used.
-Fe master alloy can be used, a commercially available Al-Si master alloy having a Si content of 25% can be used as the Si component raw material, and a commercially available Cu content of 50% Al can be used as the Cu component raw material. -Cu mother alloy can be used, and as the raw material of the Ti component, commercially available Al with a Ti content of 5%-
A Ti master alloy or a linear Al-Ti-B master alloy can be used.

Each component of Fe, Si, Cu and Ti is Al
≧ 99.7% by weight When the ingot material is melted, each of the above raw materials is added so as to be in the intended weight range.
Incidentally, Fe and Si may be contained in a small amount in the 99.7% Al ingot material, and the raw materials of the Fe and Si components are added in consideration of these amounts. Further, Cu and Ti may or may not be contained in a very small amount in the 99.7% Al ingot material, and in Cu and Ti, the respective raw materials are added in consideration of these amounts.

Next, the production method for imparting a fine intermetallic compound to the aluminum alloy support for a lithographic printing plate of the present invention as described above at a low cost and with a stable surface roughening suitability is described below. Is like. One example of the embodiment of the method for producing an aluminum alloy support used in the present invention will be described more specifically with reference to the conceptual steps of FIGS.
In a melting and holding furnace (not shown), 0 <Fe ≦ 0.20% by weight,
The Al raw material is melted and prepared so that 0 ≦ Si ≦ 0.13% by weight, and the molten metal is supplied from the molten metal supply nozzle 3 to the ingot receiving base 2 through the water-cooled mold 1 as shown in FIG.
make. In this case, the ingot is chamfered to 280 ° C or higher and 65
A temperature of 0 ° C. or lower, preferably 400 ° C. or higher and 630 ° C. or lower, particularly preferably 500 ° C. or higher and 600 ° C. or lower,
The time is 2 hours to 15 hours, preferably 4 hours to 1
After soaking for 2 hours, particularly preferably 6 hours to 11 hours, it is then rolled to 0.5 mm to 0.1 mm by a cold rolling mill 8 as shown in FIG. As shown, the straightening device 9 straightens the aluminum alloy support. Rolling may be performed by a hot rolling mill (not shown), or may be performed by combining a hot rolling mill and a cold rolling mill.

Further, as shown in FIG.
The Al raw material may be melted and prepared so that Fe ≦ 0.20% by weight and 0 ≦ Si ≦ 0.13% by weight, and a twin roll continuous casting machine 6 may be used to form a plate of 2 to 30 mm. Next, as shown in FIG. 3, cold rolling is performed by the cold rolling mill 8,
After rolling to 0.5 to 0.1 mm, it is further straightened by a straightening device 9 as shown in FIG. 4 to make an aluminum alloy support.

Further, the Al raw material is melted and prepared in the melting and holding furnace so that 0 <Fe ≦ 0.20% by weight and 0 ≦ Si ≦ 0.13% by weight, and about 4 to 3 is obtained by the twin belt continuous casting machine.
In the case of making a plate of 0 mm, thereafter, cold rolling is performed by the cold rolling mill 8 as shown in FIG. 3, and straightening is performed by the straightening device 9 as shown in FIG. 4 to make a support.
When a twin-belt continuous casting machine is used, hot rolling may be performed immediately after the continuous casting machine.

Various methods such as mechanical surface roughening, chemical surface roughening, electrochemical surface roughening, and combinations thereof can be used as the method for surface roughening the lithographic printing plate support of the present invention.
As a mechanical graining method, for example, ball grain,
Wire grain, brush grain, liquid honing method, etc. Also, as an electrochemical graining method,
The AC electrolytic etching method is generally adopted, and as the current, a normal sine wave AC current or a rectangular wave,
Special alternating current is used. Further, as a pretreatment for this electrochemical graining, etching treatment with caustic soda may be performed.

When performing electrochemical surface roughening, it is preferable that the surface is roughened by an alternating current with an aqueous solution mainly containing hydrochloric acid or nitric acid. The details will be described below. First, the aluminum alloy support is first alkali etched. Preferred alkaline agents are caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, sodium gluconate and the like. Concentration 0.01-20%, temperature 20-90
It is suitable to select the temperature and the time from the range of 5 sec to 5 min, and the preferable etching amount is 0.1.
~ 5 g / m ² .

Particularly in the case of a support containing a large amount of impurities, 0.01
-1 g / m ² is suitable (JP-A-1-237197). Subsequently, since a substance (smut) that is insoluble in the alkaline agent remains on the surface of the alkali-etched aluminum alloy support, desmut treatment may be carried out if necessary. The pretreatment is as described above, but
In the present invention, AC electrolytic etching is performed in an electrolytic solution containing hydrochloric acid or nitric acid as a main component. The frequency of the alternating electrolysis current is 0.1 to 100 Hz, more preferably 0.1 to 100 Hz.
It is 1.0 or 10 to 60 Hz. The liquid concentration is 3
˜150 g / l, more preferably 5 to 50 g / l, and the amount of aluminum dissolved in the bath is preferably 50 g / l or less, and more preferably 2 to 20 g / l. If necessary, additives may be added, but in the case of mass production, it becomes difficult to control the liquid concentration.

The current density is 5 to 100 A / dm ²
Is suitable, but 10 to 80 A / dm ² is more preferable. The power source waveform is appropriately selected depending on the required quality and the components of the aluminum alloy support used, but it is disclosed in JP-B-56-19280 and JP-B-55-1919.
It is more preferable to use the special alternating waveform described in each publication of No. 1. Such waveforms and liquid conditions are appropriately selected depending on the quality required along with the amount of electricity, the components of the aluminum alloy support used, and the like.

The electrolytically grained aluminum alloy support is then immersed in an alkaline solution as part of the smut treatment to dissolve the smut. There are various alkali agents such as caustic soda, pH 10 or higher, temperature 25 to 60 ° C,
It is preferable to perform the immersion for an extremely short time of 1 to 10 seconds. Next, it is dipped in a liquid containing mainly sulfuric acid. As the liquid condition of sulfuric acid, the concentration is 50-400 g / l, which is much lower than the conventional one.
Temperatures of 25-65 ° C are preferred. Concentration of sulfuric acid 400g /
If it is 1 or more, or if the temperature is 65 ° C. or more, corrosion of a treatment tank or the like becomes large, and in an aluminum alloy having a large manganese content (for example, 0.3% by weight), electrochemically roughened sand is used. My eyes collapse. Further, when the amount of dissolution of the aluminum alloy base material is etched by 0.2 g / m ² or more, the printing durability decreases, so 0.2 g / m ²
The following is preferable.

The anodized film has a thickness of 0.1 to 10 g / m ² ,
More preferably, 0.3 to 5 g / m ² is formed on the surface. The treatment conditions for anodization are not generally determined because they vary depending on the electrolytic solution used, but generally the concentration of the electrolytic solution is 1 to 80% by weight, the liquid temperature is 5 to 70 ° C,
Current density 0.5 to 60 A / cm ² , voltage 1 to 100 V,
A range of electrolysis time of 1 second to 5 minutes is suitable.

The thus-obtained grain-like aluminum alloy support having an anodized film is itself stable and excellent in hydrophilicity, so that it is possible to immediately form a photosensitive coating on it. If necessary, further surface treatment can be applied. For example, a silicate layer made of an alkali metal silicate or an undercoat layer made of a hydrophilic polymer compound can be provided. The coating amount of the undercoat layer is 5 to 150 mg / m
² is preferred.

Next, a photosensitive coating film is provided on the thus treated aluminum alloy support, imagewise exposed and developed to form a plate, which is then set in a printing machine to start printing.

[0031]

【Example】

(Examples 1 to 13 and Comparative Examples 1 to 13) Aluminum raw materials and the like were melted and prepared, and an ingot was prepared using a water-cooled stationary mold as shown in FIG. 1 at a pouring temperature of 720 ° C. The ingot was faced to remove about 13 mm, and then homogenized at 550 ° C. for 12 hours in a homogenizing heating furnace (not shown). After that, either one or both of cold rolling and annealing is performed.
The process was repeated more than once to finally finish the plate to a thickness of 0.24 mm. At the time of melting and preparing, Examples-1 to 7 of the present invention and Comparative Examples-1 to 7 of the present invention were prepared by changing the addition amount of the alloy component.

Further, using the twin roll continuous casting apparatus shown in FIG.
A twin-roll continuous casting machine 6 was used to prepare a continuous casting and rolling plate having a thickness of 7.5 mm, which was wound by a coiler 7. After that, any one or more steps of homogenization treatment, cold rolling and annealing were performed to finally finish the sheet to a thickness of 0.24 mm. At the time of melting / preparation, the addition amounts of alloy components were changed, and the homogenization treatment / annealing conditions were changed to prepare Examples-8-10 and Comparative Examples-8-10 of the present invention.

Further, the twin belt continuous casting apparatus shown in FIG. 5 is used to melt aluminum raw materials and the like in the melting and holding furnace 5.
A continuous cast plate having a thickness of 20 mm was prepared using the twin-belt continuous casting machine 10, and then continuously rolled by the hot rolling mill 11 into a plate having a thickness of 3 mm, which was wound by the coiler 7. After that, any one or more steps of homogenization treatment, cold rolling and annealing were performed to finally finish the sheet to a thickness of 0.24 mm. At the time of melting / preparation, the addition amount of the alloy component was changed and the annealing conditions were changed, and Examples-11 to 13 of the present invention and Comparative Example-1 were changed.
1 to 13 were created.

Table 1 shows the breakdown of each sample and the proportion of intermetallic compounds having a particle size of 0.1 μm or less.

[0035]

[Table 1]

[0036]

[Table 2]

Each of the above samples was used as a support for a lithographic printing plate, and was etched at a temperature of 50 ° C. so that the etching amount was 5 g / m ² with a 15% sodium hydroxide aqueous solution.
After washing with water, it was immersed in a sulfuric acid solution of 150 g / l, 50 ° C. for 10 seconds to desmut, and washed with water. Further support 16g /
In an aqueous nitric acid solution, the surface was electrochemically roughened using an alternating waveform current described in JP-B-55-19191.
As electrolysis conditions, the anode voltage V _A = 14 V, the cathode voltage V _C = 12 V, and the amount of electricity at the anode is
It was set to 350 coulomb / dm ² .

Next, a chemical etching treatment was carried out in a 5% aqueous solution of sodium hydroxide so that the amount of dissolution of the aluminum alloy plate was 0.5 g / m ^2, and then at 60 ° C. for 30 minutes.
A desmut treatment was performed by immersing in a 0 g / l sulfuric acid solution for 20 seconds. Furthermore, the distance between the electrodes is 150 mm in an aqueous solution of sulfuric acid 150 g / l and aluminum ion concentration 2.5 g / l.
In the above, an anodic oxidation treatment was carried out for 60 seconds with a direct current of 22V.

Examples-1 to 13 prepared as described above
And the following compositions were coated on the supports of Comparative Examples 1 to 13 so that the coating weight after drying was 2.0 g / m ² to form a photosensitive layer. (Photosensitive solution) N- (4-hydroxyphenyl) methacrylamide / 2-hydroxyethylmethacrylate / acrylonitrile / methylmethacrylate / methacrylic acid (= 15: 10: 30: 38: 7 molar ratio) copolymer (average molecular weight 60000) ・ ・ ・ 5.0 g ・ Hexafluorophosphate of the condensate of 4-diadizophenylamine and formaldehyde ・ ・ ・ 0.5 g ・ Phosphorous acid ・ ・ ・ 0.05 g ・ Victoria Pure blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) ... 0.1 g 2-methoxyethanol ... 100.0 g The photosensitive lithographic printing plate prepared in this manner was transparent negative film in a vacuum baking frame. Through a metal halide lamp of 3 kW from a distance of 1 m for 50 seconds, and then develop with a developer having the following composition at 300 ° C. for 7 minutes. After performing the burning treatment, and gumming with gum arabic solution, and a lithographic printing plate.

(Developer) ・ Sodium sulfite ・ ・ ・ 5.0 g ・ Benzyl alcohol ・ ・ ・ ・ ・ ・ 30.0 g ・ Sodium carbonate ・ ・ ・ 5.0 g ・ Sodium isopropylnaphthalene sulfonate ・ ・ ・ 12 0.0 g · Pure water ··· 1000.0 g Using the lithographic printing plate thus prepared, a printing test was conducted in a usual procedure to evaluate the printability.

Similarly, the observation of the grain shape of the aluminum alloy support before coating the photosensitive layer was carried out by a scanning electron microscope (SE).
M). In addition, the raw material costs of each sample were also compared. The above evaluation results are shown in Table 2.

[0042]

[Table 3]

[0043]

[Table 4]

Comparative Examples-1, 2, 3, 4, 5, 8, 11
The amount of Fe and Si was within the range of the present invention, but since no fine intermetallic compound having a size of 0.1 μm or less was not present, uniform grain could not be formed and the printing test was also poor. In Comparative Example-3, since high-purity Al (Al ≧ 99.99% by weight) was used, the raw material cost was also high. Comparative Examples-6, 7, 9, 10, 12, and 13 have a large amount of Fe and Si, so even if there is no fine intermetallic compound of 0.1 μm or less, a uniform grain can be formed to some extent, and the printing test is also good. However, Fe and Si must be added as raw materials,
There is a drawback that the raw material cost becomes high. Comparative Example-
In No. 4, since the amount of Ti was large, there was a problem that streaks were generated in appearance. Further, in Comparative Example-5, since the amount of Cu was large, the grains were not uniform and very coarse grains were generated.

[0045]

INDUSTRIAL APPLICABILITY As described above, the aluminum alloy support for a lithographic printing plate according to the present invention can be reduced in cost of raw materials and has excellent electrolytic surface roughening property, resulting in good performance as a printing plate. When a twin roll continuous casting device and a twin belt continuous casting device are used as the casting method as in Examples-8 to 13, not only raw material cost but also manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an example of a casting step of a method for producing a lithographic printing plate support of the present invention.

FIG. 2 is a conceptual diagram of another embodiment of the casting step of the method for producing a lithographic printing plate support of the present invention.

FIG. 3 is a conceptual diagram of an example of a cold rolling step of the method for producing a lithographic printing plate support of the present invention.

FIG. 4 is a conceptual diagram of an example of a straightening step of the method for producing a lithographic printing plate support of the present invention.

FIG. 5 is a conceptual diagram of another embodiment of the casting step of the method for producing a lithographic printing plate support of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-cooled mold 2 Ingot cradle 3 Molten metal supply nozzle 4 Ingot 5 Melt holding furnace 6 Twin roll continuous casting machine 7 Coiler 8 Cold rolling mill 9 Straightening device 10 Twin belt continuous casting device 11 Hot rolling mill

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Uesugi 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Sha Shin Film Co., Ltd.

Claims (2)

[Claims] 1. 0 <Fe ≦ 0.20% by weight, 0 ≦ Si ≦
0.13% by weight, Al ≧ 99.7% by weight, the balance being an aluminum alloy plate composed of unavoidable impurity elements, wherein the proportion of the intermetallic compounds contained in the aluminum alloy plate is 0.1 μm or less. Is present in an amount of 0.5% or more of all intermetallic compounds by weight, an aluminum alloy support for a lithographic printing plate. 2. The aluminum alloy support is 0 ≦ Ti.
The aluminum alloy support for a lithographic printing plate according to claim 1, characterized in that it contains <0.05% by weight and 0 ≦ Cu <0.05% by weight.