JPH09291329A - Substrate for lithographic plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum substrate for lithographic plate, in which the occurrence of striped fault caused by the existence of Ti grains added to aluminum or aluminum alloy for the purpose of grain refining is prevented, and its production. SOLUTION: This aluminum substrate for lithographic plate is obtained by casting Ti-containing aluminum, applying cold rolling and/or heat treatment, and subjecting the resultant sheet to straightening and to surface roughening. At this time, the width of Ti grains existing in the surface layer of the aluminum sheet, ranging from the surface to a position at a depth of 20μm from the surface, and lenticularly elongated along the rolling direction, is regulated to <=100μm. An Al-Ti or Al-Ti-B alloy composed of grains and having <1.0mm Ti grain size is added to molten aluminum and this molten aluminum alloy is directly cast and rolled continuously into cast plate of <=10mm thickness by means of a couple of cooling rolls. Subsequently, either or both of cold rolling and heat treatment are applied to this cast plate to form an aluminum alloy sheet of 0.1-0.5mm thickness. Then, straightening and surface roughing are performed. By this method, the aluminum substrate for lithographic plate can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum support for a lithographic printing plate and a method for producing the same, and particularly to prevent occurrence of streak failure due to the presence of Ti particles added to aluminum or an aluminum alloy for the purpose of grain refinement. And a method for producing the same.

[0002]

2. Description of the Related Art An aluminum plate (including an aluminum alloy plate) is used as an aluminum support for a printing plate, particularly as a support for an offset printing plate. Generally, in order to use an aluminum plate as a support for an offset printing plate, it is necessary that the aluminum plate has 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 dense grain. Since the surface roughening treatment has a remarkable effect on the printing performance and printing durability of the plate material when offset printing is actually performed after plate making, its quality is an important factor in plate material production.

An AC electrolytic etching method is generally adopted as a method for roughening an aluminum support for a printing plate, and as the current, an ordinary AC current having a sine level or a special alternating waveform current such as a rectangular wave is used. It is used. The surface of the aluminum plate is roughened by alternating current using an appropriate electrode such as graphite as a counter electrode, and is usually performed in a single process, but the pit depth obtained there is generally shallow. And the printing durability was poor. For this reason, various methods have been proposed so that an aluminum plate suitable as a support for a printing plate having a grain having uniform and dense pits deeper than the diameter thereof can be obtained. As a method thereof, a surface roughening method using a special electrolysis power source waveform (Japanese Patent Laid-Open No. 53-67507), a ratio of an electric quantity at the time of an anode and a cathode at the time of electrolytic surface roughening using an alternating current (Japanese Patent Laid-Open No. A54
-65607), power supply waveform (JP-A-55-253)
No. 81), combinations of energization amount per unit area (Japanese Patent Laid-Open No. 56-29699), and the like are known. In addition, a combination with mechanical roughening (Japanese Unexamined Patent Publication No.
No. -142695) is also known.

On the other hand, as a method of manufacturing an aluminum support, an aluminum ingot is melted and held to form a slab (thickness 400 to 600 mm, width 1000 to 2000 m).
m, 2000-6000 mm in length), and after passing through a facing process of cutting the impurity structure portion of the slab surface by a facing machine at a rate of 3 to 10 mm, removing the stress inside the slab and homogenizing the structure. 480-540 ° C in a soaking furnace,
A soaking process is performed for 6 to 12 hours, followed by hot rolling at 480 to 540 ° C. 5 to hot rolling
After rolling to a thickness of 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 produced 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 aluminum support through the process of melting and holding → casting → facing → heat equalization, heating and cooling are repeated,
Even if there is a step of chamfering the surface layer, variations in the metal alloy components and the like occur in the surface layer, causing a reduction in the yield of the 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 of making, it is possible to perform continuous casting and hot rolling from molten aluminum to form a thin plate hot rolling coil, and then subject the aluminum support that has been cold rolled, heat treated and straightened to roughening treatment. A method of manufacturing a lithographic printing plate support characterized by (JP-A-3-7
Further, as a method for producing an aluminum support having particularly good electrolytic surface roughening property, an aluminum support for a lithographic printing plate which is obtained by casting an aluminum melt, then rolling and heat-treating, and further performing straightening and roughening In the manufacturing method, a manufacturing method was proposed in which the temperature distribution of the molten metal in the molten aluminum supply nozzle was within 30 ° C at the nozzle tip. (JP-A-6-262308) Further, for the same purpose, an aluminum support for a lithographic printing plate, which is obtained by continuously casting and rolling an aluminum melt, performing cold rolling and heat treatment at least once, and further correcting and roughening the surface. In the manufacturing method, a continuous casting machine was proposed in which the molten metal temperature immediately before casting was set such that the temperature at the start of casting was higher than the temperature in steady operation by 20 ° C. or more, and continuous casting and rolling was performed. (Japanese Patent Laid-Open No. 7
-40017)

[0007]

On the other hand, the applicant of the present invention has disclosed a method for producing an aluminum support for a lithographic printing plate as described above, wherein titanium (T
It was proposed to add i) as an Al-Ti alloy or an Al-Ti-B alloy into the molten aluminum before casting or continuous casting. (For example, Japanese Patent Application No. 6-184900
Japanese Patent Application No. 6-212878, Japanese Patent Application No. 6-22673
However, when the aluminum or aluminum alloy containing Ti is produced by the method for producing an aluminum support for a lithographic printing plate as described above, streak-like defects caused by Ti are intermittent in the rolling direction of the aluminum plate. However, such defects could not be prevented. Also,
Japanese Unexamined Patent Publication No. 3-294490 describes a method of alkali-etching the surface of an aluminum plate, but this method could not prevent the generation of streak-like defects due to Ti. That is, when alkali etching is applied to an aluminum plate in which streak-like defects caused by Ti occur in the rolling direction, white rubbing scratch-like streaks are formed, and when these appear on the back surface of the lithographic printing plate aluminum support. , Reduce the commercial value because it is recognized as an aluminum scratch. In addition, when the surface roughening treatment required for a lithographic printing plate is performed, the surface is hardly roughened, resulting in black streak failure, which significantly reduces the performance of the lithographic printing plate (ink stain prevention, plate inspection). However, there is a problem that the commercial value is reduced.

The object of the present invention is to provide a method for producing an aluminum support for a lithographic printing plate by continuously casting and rolling an aluminum melt, subjecting the cast plate to cold rolling and / or heat treatment, and then straightening and roughening. Another object of the present invention is to provide an aluminum support for a lithographic printing plate which does not have streak-like defects intermittently generated in the rolling direction of an aluminum plate due to Ti added as a grain refiner and a method for producing the same.

[0009]

As a result of various studies to achieve the above object, the present inventors have found that the above object can be achieved by the present invention described below. That is, the present invention casts aluminum containing Ti,
In the aluminum support for a lithographic printing plate obtained by performing cold rolling and / or heat treatment and straightening / roughening, the aluminum support is stretched into a lens shape along the rolling direction existing in the range of 0 to 20 μm of the surface layer of the aluminum plate. The width of the Ti particles formed is 100
the aluminum support for a lithographic printing plate and the aluminum melt containing Ti or Ti and B
Is added to the aluminum alloy, and a cast plate having a thickness of 10 mm or less is continuously cast and rolled by a pair of cooling rolls, and either or both of cold rolling and heat treatment are performed on the cast plate to obtain a thickness of 0.1. In the method for producing an aluminum support for a lithographic printing plate by making an aluminum alloy plate of 0.5 mm and then straightening and roughening it, the Ti particle size is 1.0.
Al-Ti alloy or Al-T consisting of particles less than mm
A method for producing a lithographic printing plate support, which comprises using an i-B alloy.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
FIG. 1 is a schematic view showing an example of a continuous casting and rolling apparatus according to the present invention, in which a molten aluminum or aluminum alloy is held in a melting and holding furnace 1 and the furnace 1 is tilted by a melting and holding furnace tilting motor 9, Is poured into a gutter 2 and is sent from a molten metal supply nozzle 3 to a twin roll continuous casting and rolling machine 4 having cooling rolls 4a and 4b, and an aluminum plate is continuously cast and rolled while solidifying and cooling between the cooling rolls.
To take up. Reference numeral 7 denotes a molten metal level meter which detects the level of the molten metal on the gutter, sends level information from the amplifier 8 to the tilting motor 9, and holds the molten aluminum on the gutter 2 at a constant level. Reference numeral 5 denotes a cutter, which winds a fixed amount of a rolled aluminum plate around a coiler and cuts the aluminum plate. In the present invention, as described above,
As the grain refiner, for example, Ti is used in the apparatus shown in FIG. 1 as an Al-Ti alloy wire or Al-Ti-B made of particles having a Ti particle diameter of less than 1.0 mm (1000 μm).
The alloy wire 10 is added to the molten aluminum. In this case, the total amount of Ti contained in the aluminum support is 0.
005-0.03%, preferably 0.008-0.02
% Al-Ti alloy wire or Al-Ti
-Add the B alloy wire into the molten aluminum. In addition,
As the alloy to be added, it is preferable to use an Al-Ti-B alloy. The size of Ti particles contained in the wire is
It can be confirmed by analyzing the cross section of the wire with an electronic block microanalyzer. The size of Ti particles is 1.
It is essential to use wires of 0 mm or less. Here, the Ti particles mean a compound such as AlTi ₃ , TiB _2, Ti alone or an aggregate thereof. In order to reduce the size of the Ti particles contained in the wire to 1.0 mm or less, for example, a molten Al melt (for example, Al99.
An Al-Ti alloy is produced by melting metal Ti in 7% by weight) and then solidifying it in a linear or block shape. Before solidification, a filter capable of removing Ti particles of 1 mm or more (for example, It is possible to use a method of applying a glass filter or the like, or a method of subjecting the molten metal before solidification to a stirring process in which a shearing force is applied. The thickness of the cast aluminum plate obtained by the continuous casting and rolling device is preferably 1 to 7 mm. The aluminum plate wound on the coiler 6 is then cooled by the cold rolling mill 11 illustrated in FIG.
Further, cold rolling and heat treatment are performed by the heat treatment machine 12 (a) illustrated in FIG. In the present invention, only one of cold rolling and heat treatment may be performed as necessary. The cold rolling and / or heat treatment is an operation performed for homogenizing and flattening the structure of the aluminum plate obtained by continuous casting and rolling, and in the present invention, both the cold rolling and the heat treatment are performed. 3 mm to 0.5 mm when performing
, And then heat-treated, and then cold-rolled to finish an aluminum plate having a thickness of 0.5 to 0.1 mm. When heat treatment is not performed, the aluminum plate is finished by cold rolling to a thickness of 0.5 mm to 0.1 mm.
The heat treatment method includes a continuous annealing device 12 as shown in FIG.
There are two methods, (a) and the batch annealing apparatus 12 (b) shown in FIG. 4, and either method may be selected. In the case of the continuous annealing method, heat treatment is performed at a temperature of 400 ° C. to 600 ° C. for a time of 1 second to 600 seconds. 300 ° C to 6 for batch annealing
Heat treatment is performed at 00 ° C. for 1 to 12 hours. Next, the aluminum plate is straightened by the straightening device 13 illustrated in FIG. 5 to make an aluminum support. In the present invention, the corrected aluminum support is roughened to obtain a planographic printing plate support. The method for roughening the aluminum support in the present invention may be any of various methods such as mechanical roughening, chemical roughening, electrochemical roughening, and a combination thereof. Mechanical graining methods include, for example, ball grain, wire grain, brush grain,
There is a liquid honing method. As an electrochemical graining method, an AC electrolytic etching method is generally adopted, and a special alternating current such as a normal sine wave AC current or a rectangular wave is used as a current. In addition, as a pretreatment for the electrochemical graining, an 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. This will be described in detail below. First, the aluminum support is first alkali etched. Preferred alkaline agents are caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, sodium gluconate and the like. It is appropriate that the concentration is selected from the range of 0.01 to 20%, the temperature is 20 to 90 ° C., and the time is 5 sec to 5 min.
m ² . Particularly in the case of a support containing a large amount of impurities, 0.01
１1 g / m ² is appropriate. (JP-A-1-237197)
Issue). Subsequently, since a substance (smut) insoluble in alkali remains on the surface of the alkali-etched aluminum plate, desmutting may be performed as necessary.

The pretreatment is as described above, but
In the present invention, alternating current electrolytic etching is performed in an electrolytic solution mainly containing hydrochloric acid or nitric acid. The frequency of the alternating current is 0.1 to 100 Hz, preferably 0.1 to 1.
0 or 10 to 60 Hz. The liquid concentration is 3 to 1
50 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. Additives may be added if necessary, but in the case of mass production, it becomes difficult to control the liquid concentration. The current density is 5 to 1
00A / dm ² is suitable, but 10 to 80A / dm ²
Is more preferred. The power source waveform is properly selected depending on the required quality and the components of the aluminum support used, but the Japanese Patent Publication Nos. 56-19280 and 55.
It is more preferable to use the special alternating waveform described in each of Japanese Patent Publication No. 19191. Such waveform and liquid conditions are appropriately selected depending on the quality required together with the quantity of electricity, the components of the aluminum support used, and the like.

The electrolytically grained aluminum is then immersed in an alkaline solution as part of the smut treatment to dissolve the smut. As the alkaline agent, there are various types such as caustic soda, and the pH is 10 or more, the temperature is 25 to 60 ° C, and the immersion time is 1
It is preferable to carry out in a very short time of 10 to 10 sec. Next, it is immersed in a liquid mainly composed of sulfuric acid. As the liquid condition of sulfuric acid, the concentration is 50-400 g / l, the temperature is 25-
65 ° C. is preferred. If the concentration of sulfuric acid is 400 g / l or more, or if the temperature is 65 ° C. or more, corrosion of the treatment tank and the like becomes large, and the aluminum alloy containing 0.3% or more of manganese has electrochemically roughened sand. My eyes collapse. The dissolution amount of the aluminum base is 0.2 g / m
^{If two} or more etchings are performed, the printing durability will decrease. Therefore, it is preferable that the etching resistance be 0.2 g / m ² or less.

The anodic oxide 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 anodizing treatment conditions are not generally determined since they vary depending on the electrolytic solution used, but generally the concentration of the electrolytic solution is 1 to 80% by weight, and the liquid temperature is 5 to 70%.
C, current density 0.5 to 60 A / cm ² , voltage 1 to 100
V, an electrolysis time of 1 second to 5 minutes is appropriate. The grained aluminum plate having an anodized film obtained in this way is stable and excellent in hydrophilicity, so that a photosensitive film can be immediately provided on the surface, but if necessary, the surface can be further coated. Processing can be performed.

For example, a silicate layer made of the alkali metal silicate described above or an undercoat layer made of a hydrophilic polymer compound can be provided. The coating amount of the undercoat layer is preferably from 5 to 150 mg / m ² .

Next, a photosensitive coating film is provided on the thus treated aluminum support, imagewise exposed and developed to form a plate, which is then set in a printing machine to start printing. The aluminum support for a lithographic printing plate obtained by the above method has a surface layer of the support of 0 to 20 μm, preferably 1 to 10 μm.
The width of the Ti particles extending in a lens shape along the rolling direction existing in the range of m is 100 μm or less, preferably 70 μm.
By setting it to be equal to or less than m, it is possible to prevent streak-like defects caused by Ti which are intermittently generated in the rolling direction of the aluminum plate.

[0017]

The present invention will be specifically described below with reference to examples. Examples-1, -2 and Comparative Examples-1, -2, -3 Using the continuous casting and rolling apparatus shown in FIG. 1, an aluminum plate was continuously cast and rolled as follows. First, melting and holding furnace 1
Fe: 0.30 wt% (same below), Si: 0.05%, Cu:
An aluminum melt was prepared so that 0.01% remaining Al and unavoidable impurities would be prepared and kept at 775 ° C. Melting and holding furnace 1
Tilted to pour molten aluminum into the gutter 2 and send it from the molten metal supply nozzle to the continuous casting and rolling mill 1 having the cooling rolls 4a and 4b, and solidify and cool between the cooling rolls to a thickness of 7.0 m.
m aluminum plate was continuously cast and rolled. At this time, Al-
Ti (5%)-B (1%) alloy wire as grain refiner
It was supplied to the aluminum melt of the gutter 2 from the position of and was melted by setting the supply rate so that the Ti concentration in the aluminum melt was 0.01%. (Example 1) Further, in order to prepare other example samples and comparative example samples, the supply rate of the aluminum alloy as the crystal grain refiner was changed, or Al-Ti (5%)-was added to the melting and holding furnace. B (1%)
The alloy block of 1 was charged and melted. Here, Example-2
Is Al-Ti (5%)-B in the same manner as in Example-1.
(10%) alloy wire was used, and the supply rate was set so that the Ti concentration in the molten aluminum was 0.04%. Comparative Example-1 was prepared in the same manner as in Example-2 by setting the supply rate so that the Ti concentration in the molten metal would be 0.07%. In Comparative Example-2, the melting and holding furnace was equipped with Al-Ti (5
(0%)-B (1%) alloy block was charged and melted, and it was produced so that the Ti concentration in the molten aluminum was 0.04%. Comparative Example-3 was produced in the same manner as Comparative Example-2 by setting the supply rate so that the Ti concentration in the molten aluminum was 0.1%. During casting, the molten metal surface level of the gutter 2 was measured by a level meter 7, and the holding furnace tilting motor 9 of the melting and holding furnace was controlled via an amplifier 8 to make the amount of molten metal supplied constant. The sample produced in this manner is used for the coiler 6
The sample web was wound up and cut with a cutter 5 as appropriate. Then, with a cold rolling mill shown in FIG.
After being rolled to a thickness of 0.2 mm, the batch type heat treatment (annealing) apparatus shown in FIG. 4 was used to perform heat treatment at 480 ° C. for 10 hours, and the thickness was 0.24 mm again using a cold rolling mill. The samples thus finished were classified according to the method of introducing the Al-Ti (5%)-B (1%) alloy, and the distribution of Ti on the surface of the aluminum plate was confirmed to confirm Example 1 of the present invention, -2 and Comparative Example-1,-
Two or three aluminum plates were used. First, in order to confirm the level of streaks caused by Ti, each of the above aluminum plates was treated with a sodium aluminate (Al ³⁺ 10%, NaOH 30%) solution to obtain 60
The appearance was evaluated by performing etching treatment at 30 ° C. for 30 seconds. In addition, in order to evaluate the printing performance, the above-mentioned Example-1,
-2, the aluminum plates of Comparative Examples-1, -2 and -3 were separately prepared and used as a support for a lithographic printing plate, and the temperature was adjusted with a 5% caustic soda aqueous solution so that the etching amount was 5 g / m ^2. It was etched at 50 ° C., washed with water, immersed in sulfuric acid at 150 g / liter, 50 ° C. for 10 seconds to desmut, and washed with water. Further, the support was electrochemically roughened in a 16 g / liter aqueous nitric acid solution using an alternating waveform current described in JP-B-55-19191. As electrolysis conditions, the anode voltage V _A = 14 V and the cathode voltage V _C = 12 V, and the amount of electricity at the anode is 3
It was set to 50 coulomb / dm ² . Then, a chemical etching treatment was performed in a 5% aqueous solution of sodium hydroxide so that the dissolution amount of the aluminum alloy plate was 0.5 g / dm ^2, and then the solution was placed in a 300 g / liter sulfuric acid aqueous solution at 60 ° C. for 20 seconds. It was immersed and desmutted. Furthermore, the distance between the electrodes is 150 mm in an aqueous solution of sulfuric acid 150 g / liter and aluminum ion concentration 2.5 g / liter.
In the above, the anodization treatment was carried out for 60 seconds with a direct current of 22 V.

Examples 1 and 2 produced as described above
And Comparative Example 1, -2, the following composition aluminum support obtained by -3, coating weight after drying a photosensitive layer by coating so as to become 2.0 g / m ^2. Photosensitive liquid N- (4-hydroxyphenyl), methacrylamide / 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid (= 15: 10: 30: 38: 7 molar ratio) copolymer (average molecular weight 60000).・ ・ 5.0g Hexafluorophosphate of condensate of 4-diazisophenylamine and formaldehyde ・ ・ ・ 0.5g Phosphorous acid ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ 0.05g Dicttoria Pure BOH (manufactured by Hodogaya Chemical Co., Ltd.) ・ ・ ・ 0.1g 2-methoxyethanol ・ ・ ・ ・・ ・ ・ 100.0 g The photosensitive lithographic printing plate thus prepared was exposed through a transparent negative film in a vacuum baking frame for 50 seconds with a metal halide lamp of 3 kw from a distance of 1 m. After exposing to light, it was developed with a developer having the following composition and gummed with an aqueous solution of gum arabic to obtain a lithographic printing plate.

Developer Sodium phosphite: 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, the usual procedure is used. The print was evaluated. Table 1 shows the results of the appearance evaluation and the print evaluation after the above alkali treatment.

[0020]

[Table 1]

As is clear from the above results, the sample of the present invention has a Ti distribution on the surface of the aluminum support.
It can be seen that when the width is 100 μm or less, no streak-like defects are generated and the printing result is good. Examples -3, -4, -5, -6 and Comparative Examples -4, -5 Fe: 0.20%, Si: 0.03%, Cu:
An aluminum melt containing 0.003% remaining Al and inevitable impurities was prepared and kept at 775 ° C. Hereinafter, Example 1
An aluminum plate having a thickness of 7.0 mm was continuously cast and rolled in the same operation as in. At this time, 6 kinds of Al-Ti (5%)-B (1%)
The Al alloy wire of No. 3 was produced by changing the dispersed state of Ti contained therein (particle diameter of Ti). That is, 4 kinds of particles having a Ti particle diameter within the range of the present invention and 2 kinds of particles having a particle diameter outside the range of the present invention were prepared, and each of them was used in Examples -3 and -4.
Used for -5, -6 and for Comparative Examples -4, -5. Then, the cold rolling mill shown in FIG. 2 finished the thickness to 0.24 mm. The aluminum plate thus finished was evaluated in the same manner as in the above-mentioned example, and the distribution state of Ti on the aluminum plate surface was also confirmed. The results are shown in Table 2.

[0022]

[Table 2]

As is clear from the above results, in the examples of the present invention, the occurrence of streaks due to Ti is reduced, and a lithographic printing plate support excellent in appearance and printing results can be manufactured. In addition, in common with the above Examples -1 to -6 and each comparative example, the Ti distribution width of the aluminum plate surface,
To measure the Ti particle size in an Al-Ti (5%)-B (1%) aluminum alloy wire, an electron probe microanalyzer (EPMA) (JXA-8800M, JEOL Ltd.)
Manufactured), acceleration voltage 20 kV, average current 1.0 × 1
A method of mapping analysis under the condition of 0 ^-6 A was used. Further, FIG. 6 is an EPMA photograph showing the metal structure of the surface of the aluminum support obtained in Example 2 of the present invention, which is about 90 μm.
m-width Ti was detected. FIG. 7 is an EP showing the metal structure of the surface of the aluminum support of Comparative Example 2 (conventional product).
Approximately 400 μm wide Ti was detected in the MA photograph. White portions in the photograph indicate that the concentration of Ti is high. As is clear from the comparison of both figures, it is understood that the occurrence of streak defects due to Ti is extremely small on the surface of the aluminum support according to the present invention.

INDUSTRIAL APPLICABILITY As described above, the lithographic printing plate produced by the method for producing a lithographic printing plate support of the present invention has less streaky defect areas due to Ti and a poor appearance in comparison with the conventional one. It is possible to prevent the occurrence and to improve the printing performance. Further, the streamlining of the manufacturing process of the aluminum support has a large effect of reducing raw material costs, and particularly contributes significantly to quality improvement and cost reduction of a lithographic printing plate support.

[Brief description of drawings]

FIG. 1 is a side view of a twin roll continuous casting and rolling apparatus which is a part of an embodiment of the method for producing a lithographic printing plate support of the present invention.

FIG. 2 is a side view of a cold rolling step in the method for producing a lithographic printing plate support of the invention.

FIG. 3 is a side view of a heat treatment step (continuous annealing apparatus) of the method for manufacturing a lithographic printing plate support of the present invention.

FIG. 4 is a side view of a heat treatment step (batch annealing apparatus) of the method for manufacturing a lithographic printing plate support of the present invention.

FIG. 5 is a side view of the straightening step of the method for producing a lithographic printing plate support of the present invention.

FIG. 6 is an EPMA showing the metallographic structure (Ti distribution) of the surface of the aluminum support obtained in Example 2 of the present invention.
Photo

FIG. 7 EP showing a metallographic structure (Ti distribution) on the surface of an aluminum support obtained by a conventional method (Comparative Example 2).
MA photo

[Explanation of symbols]

 1 Melt-holding furnace 2 Molten metal 3 Melt-holding nozzle 4 Twin roll continuous casting and rolling mill 5 Cutter 6 Coiler 7 Molten metal level meter 8 Amplifier 9 Melt-holding furnace tilting motor 10 Finer agent wire feeding position 11 Cold rolling mill 12 Heat treatment machine 13 Straightening apparatus

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B41N 1/08 B41N 1/08 C22F 1/04 C22F 1/04 A

Claims (2)

[Claims] 1. Casting aluminum containing Ti,
In an aluminum support for a lithographic printing plate obtained by performing cold rolling and / or heat treatment and straightening / roughening, the aluminum support is extended in a lens shape along a rolling direction existing in a range of 0 to 20 μm of a surface layer of an aluminum plate. The width of the Ti particles formed is 100
An aluminum support for a lithographic printing plate, which has a thickness of at most μm. 2. Ti or an aluminum alloy containing Ti and B is added to an aluminum melt, and a cast plate having a thickness of 10 mm or less is continuously cast and rolled by a pair of cooling rolls, and the cast plate is subjected to cold rolling and heat treatment. Do either or both,
In a method for producing an aluminum support for a lithographic printing plate by making an aluminum alloy plate having a thickness of 0.1 to 0.5 mm and then straightening and roughening it, an Al-Ti comprising particles having a Ti particle diameter of less than 1.0 mm. Alloy or Al-Ti-B
A method for producing a support for a lithographic printing plate, which comprises using an alloy.