JP2002079770A - Lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithographic printing plate excellent in handling property without generating any mistake in the recognition of vertical and horizontal directions upon plate making work or attaching work of the plate to a printing press. SOLUTION: The lithographic printing plate is provided with a light sensitive layer on one surface of the same and a woodgrain pattern or a texture pattern on the other surface of the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate, and more particularly to a lithographic printing plate excellent in handleability because the rolling direction of a used rolled aluminum plate can be easily determined.

[0002]

2. Description of the Related Art Hitherto, as a lithographic printing plate, a plate obtained by subjecting an aluminum plate to a surface roughening treatment and providing a photosensitive layer has been used. This lithographic printing plate is used by being bent at both ends after plate making work to provide an image and mechanically attached to a plate cylinder of a printing press, but as printing is performed, the fixed portion is deformed or There has been a problem in that the printer may be damaged to cause troubles such as printing misalignment, or the bent portion may be cut off (grip) to make printing impossible. On the other hand, it has been proposed to improve the fatigue strength by setting the alloy composition of the aluminum plate to a specific range (Japanese Patent Publication No. 3-11635). However, since the aluminum plate has different strength characteristics between the rolling direction and the direction orthogonal thereto, usually, even when the above problem does not occur, the length and width of the lithographic printing plate are erroneously reversed during the plate making process or mounting on a printing press. Then, the sheet is bent along the rolling direction which is weak in bending and is attached to the printing press, which may cause a cut. Therefore, there is a demand for a lithographic printing plate that does not misrecognize the vertical and horizontal directions during the plate making operation or the mounting operation to the printing press.

On the other hand, a number of methods have been proposed for applying numbers, characters, patterns, designs and the like to the surface of a lithographic printing plate having no photosensitive layer. For example, JP-A-7-76800 and JP-A-6-286352 disclose a surface of a lithographic printing plate support on which a photosensitive layer is not provided (hereinafter, also referred to as a "back surface". The same applies to a lithographic printing plate. A method of performing an electrochemical surface-roughening treatment is disclosed in JP-A-7-205563, and a method of performing an alkali etching treatment on the back surface of a lithographic printing plate support is disclosed. Japanese Patent Application Laid-Open No. 6-305271 discloses a method in which a back surface of a lithographic printing plate support is subjected to a press treatment using a transfer roll. Japanese Patent Application Laid-Open No. 6-73478 describes a method of obtaining a discontinuous pattern having a specific color tone on an aluminum alloy plate by anodizing treatment. However, all of these methods require the processing steps of electrochemical surface roughening treatment, alkali etching treatment, press treatment using a transfer roll, or anodic oxidation treatment. When a lithographic printing plate is manufactured by applying patterns, designs, and the like, there is a problem that the number of steps increases.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a planographic printing plate which is excellent in handleability without erroneously recognizing the vertical and horizontal directions during a plate making operation or a mounting operation to a printing press, and particularly, a plate making operation during plate making operation. It is an object of the present invention to provide a lithographic printing plate which does not make mistakes in vertical and horizontal recognition during installation work on a printing press, is excellent in handleability, and has a small number of manufacturing steps.

[0005]

SUMMARY OF THE INVENTION The present invention provides a lithographic printing plate having a photosensitive layer on one side and a grain or streak pattern on the other side.

The present invention also relates to the lithographic printing plate, wherein the lithographic printing plate support is provided with a photosensitive layer on a roughened surface of the lithographic printing plate support. It is characterized in that at least one surface of an aluminum rolled plate obtained by continuous roll casting and cold rolling is subjected to a roughening treatment, and the other surface is subjected to an alkali etching treatment and a desmutting treatment to provide a grain pattern. Provide a lithographic printing plate.

The present invention also relates to the lithographic printing plate, wherein the lithographic printing plate support is provided with a photosensitive layer on the roughened surface of the lithographic printing plate support, wherein the lithographic printing plate support comprises One surface of an aluminum rolled plate obtained by continuous belt casting, hot rolling and cold rolling is subjected to at least a surface roughening treatment, and the other surface is subjected to an alkali etching treatment and a desmutting treatment to provide a streak pattern. A lithographic printing plate is provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present invention provides a lithographic printing plate having a photosensitive layer on one side and a grain pattern or streak pattern on the other side. The planographic printing plate of the present invention has a grain-like pattern or a streak-like pattern on a surface having no photosensitive layer, that is, on the back surface. FIG.
FIG. 2 is a view showing an example of the planographic printing plate 1 of the present invention having a grain pattern on the back surface. FIG. 2 is a diagram showing an example of the planographic printing plate 2 of the present invention having a stripe pattern on the back surface.
As shown in FIGS. 1 and 2, the planographic printing plate of the present invention has a grain pattern or streak pattern on the back surface.
The rolling direction of the used aluminum rolled plate can be determined very easily from the relationship between the pattern and the rolling direction,
There is no mistake in vertical and horizontal recognition during plate making or installation on a printing press. Therefore, it does not bend along the rolling direction which is vulnerable to bending at the time of attachment to the printing press, thereby causing no cut. That is, the planographic printing plate of the present invention is excellent in handleability.

The following methods (1) and (2) are preferably exemplified as a method for providing a grain pattern or a streak pattern on the back surface. (1) Lithographic printing in which a 0.1 to 0.6 mm-thick rolled aluminum plate obtained by twin-roll continuous casting and cold rolling is subjected to an alkali etching treatment and a desmutting treatment to provide a grain pattern on the back surface. A method for producing a lithographic printing plate using a plate support. (2) A 0.1 to 0.6 mm thick aluminum rolled plate obtained by twin belt continuous casting, hot rolling and cold rolling is subjected to an alkali etching treatment and a desmutting treatment to provide a streak pattern on the back surface. A method for producing a lithographic printing plate using a lithographic printing plate support comprising:

According to the above method (1) or (2),
A grain pattern or streak pattern derived from the aluminum crystal structure of the rolled aluminum plate to be used is obtained. That is, the lithographic printing plate comprising the photosensitive layer provided on the surface of the lithographic printing plate support subjected to the surface roughening treatment, wherein the lithographic printing plate support is formed by twin-roll continuous casting and cold rolling. A surface of the rolled aluminum sheet having a thickness of 0.1 to 0.6 mm obtained by subjecting at least one surface to a roughening treatment, and performing an alkali etching treatment and a desmutting treatment to the other surface to provide a wood grain pattern. A lithographic printing plate characterized by the above, wherein the lithographic printing plate comprising a photosensitive layer provided on the surface of the lithographic printing plate support subjected to the surface roughening treatment,
The lithographic printing plate support has a thickness of 0.1 to 0.6 mm obtained by twin belt continuous casting, hot rolling and cold rolling.
The lithographic printing plate according to the present invention is characterized in that at least one surface of the rolled aluminum plate is subjected to a roughening treatment, and the other surface is subjected to an alkali etching treatment and a desmutting treatment to form a streak pattern. Is a preferred embodiment of the lithographic printing plate. In particular, when the alkali etching treatment and the desmutting treatment are simultaneously performed on the surface on which the photosensitive layer is provided and the back surface by the method (1) or (2), a wood-grain pattern on the back surface is not required. Alternatively, a lithographic printing plate obtained as described above is particularly preferable because a streak pattern is obtained.

[0011] Further, the present invention will be described in detail with specific examples.
The present invention is not limited to these. The aluminum plate used in the lithographic printing plate of the present invention is a dimensionally stable metal containing aluminum as a main component, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of a different element can also be used.

In the following description, various substrates made of the above-mentioned aluminum or aluminum alloy are collectively used as an aluminum plate. The foreign elements that may be included in the aluminum alloy include silicon, iron, manganese,
There are copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like, and the content of the foreign element in the alloy is 10% by mass or less.

In the present invention, it is preferable to use a pure aluminum plate. However, since pure aluminum is difficult to produce due to refining technology, it may contain a slightly different element. As described above, the composition of the aluminum plate used in the present invention is not specified, and a conventionally known and used material, for example, JIS A105
0, JIS A1100, JIS A3005, JIS
A3004, an aluminum alloy plate such as Internationally Registered Alloy 3103A can be used as appropriate. The thickness of the aluminum plate used in the present invention is 0.1 to 0.6.
mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the desire of the user.

In order to obtain the above aluminum plate, for example, the following method can be adopted. First, a cleaning treatment is applied to a molten aluminum prepared to a desired component according to a conventional method. In the cleaning treatment, flux treatment, Ar gas, and the like are used to remove unnecessary gases such as hydrogen in the molten metal.
Degassing treatment using Cl gas, etc., so-called rigid media filters such as ceramic tube filters and ceramic foam filters, filters using alumina flakes and alumina balls as filter media, glass cloth filters etc. A process combining gas and filtering is performed.

Then, the molten aluminum alloy is cast by twin roll continuous casting or twin belt continuous casting to form an aluminum cast plate, and then rolled to obtain a rolled aluminum plate.

First, the twin roll continuous casting used in the present invention will be described. First, an ingot is melted and held in a melting and holding furnace. The molten aluminum is supplied from the melting and holding furnace to the twin roll continuous caster, and the aluminum cast plate is directly manufactured by the twin roll continuous caster. The cast aluminum plate may be wound directly on a coiler to form a coil, or may be subsequently processed by a cold rolling mill, a heat treatment device, and a straightening device, and then wound on a coiler.

The manufacturing conditions will be described. In the melting and holding furnace, it is necessary to maintain the temperature at or above the melting point of aluminum. The temperature varies depending on the aluminum alloy component, but is generally 800 ° C. or more. As a casting method of the twin roll continuous casting machine, for example, a hunter method and a 3C method are mentioned. The casting temperature depends on the cooling conditions of the mold, but generally the optimal temperature is around 700 ° C. The thickness of the aluminum casting plate manufactured by the twin roll continuous casting machine is, for example,
It can be 1 to 30 mm. The crystal grain size after continuous casting, cooling conditions, casting speed, and the thickness change during casting are appropriately controlled. The aluminum cast plate obtained by the twin-roll continuous casting in this way is, by a cold rolling mill,
It is rolled to a desired thickness to form a rolled aluminum plate.
Thereafter, in order to adjust the crystal grains to a desired size, the grains may be treated by a heat treatment apparatus as intermediate annealing or the like, and further may be treated by a cold rolling mill. Next, a straightening process is performed by a straightening device, and desired flatness can be given. This straightening process may be performed in the last cold rolling mill. The final thickness of the rolled aluminum plate is preferably 0.1 to 0.6 mm.

Next, the twin belt continuous casting used in the present invention will be described. First, an ingot is melted and held in a melting and holding furnace. The molten aluminum is supplied from the melting and holding furnace to a twin-belt continuous caster, and an aluminum cast plate is manufactured by the twin-belt continuous caster. After reducing the thickness of this cast aluminum plate with a hot rolling mill to form a rolled aluminum plate, it may be wound on a coiler to form a coil, and subsequently processed by a cold rolling mill, a heat treatment device, and a straightening device. After that, it may be wound around a coiler. In addition, the twin belt continuous casting has an advantage that the production capacity is extremely large as compared with the twin roll continuous casting.

The manufacturing conditions will be described. Examples of the casting method of the twin-belt continuous casting machine include a Hazelley method using a metal belt and an Als Swiss Caster II using a caterpillar-shaped block. The thickness of the cast aluminum plate manufactured by the twin belt continuous casting machine can be, for example, 10 to 100 mm, and the thickness of the rolled aluminum plate rolled by the hot rolling machine is, for example,
It can be 1 to 30 mm. Other casting conditions are the same as in the case of the twin roll continuous casting described above. The rolled aluminum plate obtained by twin belt continuous casting and hot rolling is rolled to a desired thickness by a cold rolling mill. The subsequent processing is the same as in the case of the twin roll continuous casting described above. The final thickness of the rolled aluminum plate is 0.1
It is preferably set to 0.6 mm.

The aluminum plate obtained as described above is then subjected to a surface roughening treatment so as to be used as a lithographic printing plate support. Aluminum plate used in the present invention,
It is preferable to perform a surface roughening process including an electrolytic surface roughening process, but only the electrolytic surface roughening process may be performed, and an electrolytic surface roughening process, a mechanical surface roughening process, or a chemical roughening process may be performed. It may be performed in combination with the chemical treatment. Among them, it is more preferable to combine the electrolytic surface roughening treatment and the mechanical surface roughening treatment,
In particular, it is preferable to perform an electrolytic surface roughening treatment after the mechanical surface roughening treatment. In the lithographic printing plate support used in the lithographic printing plate of the present invention, the surface subjected to the following surface treatment is not particularly limited, but as an aluminum plate, an aluminum rolled plate obtained by twin-roll continuous casting and cold rolling In the case of using, the upper surface at the time of casting is the surface on which the photosensitive layer is provided and subjected to the following surface treatment, and the lower surface at the time of casting is used as the back surface and subjected to alkali etching and desmutting. This is preferable because the visibility of the pattern on the back surface is excellent.

The mechanical surface roughening treatment is performed for the purpose of making the surface of the aluminum plate generally have an average surface roughness of 0.35 to 1.0 μm. In the present invention, the conditions of the mechanical surface roughening treatment are not particularly limited, and for example, ball grain, wire grain, brush grain, and liquid honing can be used. In addition, Japanese Patent Application Laid-Open No. 6-135
175 and Japanese Patent Publication No. 50-40047. When a mechanical surface roughening treatment is applied, the surface roughness of the aluminum plate is usually reduced,
The average arithmetic roughness (Ra) can be 0.35 to 1.0 μm. By performing this mechanical roughening treatment, the water retention of the non-image portion during printing can be increased. On the other hand, the chemical surface roughening treatment is not particularly limited, either, and a known method can be used. For example, a method of immersing an aluminum plate in an alkali bath, a method of spraying an alkaline solution, and a method of applying an alkaline solution can be used.

The alkali etching treatment is for the purpose of removing rolling oil, dirt and natural oxide film on the surface of the aluminum plate, and when a mechanical roughening treatment is performed, a mechanical roughening treatment is performed. It is performed for the purpose of dissolving the edge portion of the unevenness generated by the above and obtaining a surface having a smooth undulation. The alkali etching process is a chemical etching process in an alkaline aqueous solution. Examples of the alkali used in the aqueous alkali solution include sodium hydroxide, potassium hydroxide, tribasic sodium phosphate, and the like as described in JP-A-57-16918.
There are sodium aluminate, sodium carbonate and the like, and these can be used alone or in combination. The concentration of the aqueous alkali solution is preferably from 5 to 30% by mass, and particularly preferably from 20 to 30% by mass. The concentration of aluminum dissolved in the alkaline aqueous solution is
It is preferably from 0.5 to 30% by mass. Etching with an alkali aqueous solution is performed at a liquid temperature of 25 to 90 ° C. for 1 to 120
It is preferable to perform second processing. Aluminum dissolution amount is 2 ~
20 g / m ² .

Generally, a substance (smut) unnecessary for alkali is generated on the surface of an aluminum plate by the alkali etching treatment. In this case, phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, chromic acid, or two of these substances are used. It is preferable to remove the smut by performing a desmut treatment with a mixed acid containing at least one kind of acid. The desmutting time is preferably from 1 to 30 seconds. The liquid temperature is from room temperature to 70 ° C.

The electrolytic surface roughening treatment is suitable for producing a lithographic printing plate having excellent printability since it is easy to provide fine irregularities (pits) on the surface of an aluminum plate.
The electrolytic surface-roughening treatment is performed in an aqueous solution mainly containing nitric acid or hydrochloric acid by using direct current or alternating current. A crater or honeycomb-shaped pit having an average diameter of about 0.2 to 20 μm is formed on the surface of the aluminum plate by electrolytic surface roughening treatment.
It can be produced with an area ratio of 100%. The pits have an effect of improving the resistance of the non-image portion of the printing plate to stain (stain resistance) and the printing durability. In the electrolytic surface-roughening treatment, an important condition is an amount of electricity necessary for providing sufficient pits on the surface, that is, a product of a current and a conduction time. Forming a sufficient pit with a smaller amount of electricity is preferable from the viewpoint of energy saving. In the present invention, the conditions for the electrolytic surface-roughening treatment are not limited, and can be performed under general conditions.

In a preferred embodiment of the lithographic printing plate support used in the lithographic printing plate of the present invention, after the electrolytic surface roughening treatment, an alkali etching treatment is further performed. This alkali etching treatment is performed for the purpose of quickly removing the smut component generated in the preceding electrolytic surface roughening treatment. The amount of aluminum dissolved is preferably 0.05 to 5 g / m ² . The composition of the aqueous solution used for etching,
The temperature, the processing time, and the like are selected from the ranges described above for the alkaline etching treatment before the electrolytic surface roughening treatment.

Further, desmutting treatment is preferably performed. The conditions of this desmutting process are selected from the range described above for the desmutting process after the alkali etching process before the electrolytic surface roughening process.

Following the above-mentioned roughening treatment and other treatments carried out as required, usually, an anodic oxidation treatment is carried out to increase the abrasion resistance of the surface of the aluminum plate to form an anodic oxide film. However, in the present invention, it is preferable to perform anodizing treatment. The anodic oxide film can be formed by immersing an aluminum plate as an electrode in an electrolytic solution and passing an electric current through it. As a current passed in the anodizing treatment, a current having various waveforms such as a direct current and an alternating current is selected according to the purpose. As the electrolyte used for the anodic oxidation treatment, if it forms a porous oxide film,
Anything can be used, generally sulfuric acid,
Phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes can be determined as appropriate depending on the type of electrolyte. Since the anodizing treatment conditions vary depending on the electrolyte used, they cannot be specified unconditionally. In general, however, the concentration of the electrolyte is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 1 to 60A / d
It is appropriate that m ² , the voltage is 1 to 100 V, and the electrolysis time is 10 seconds to 5 minutes. Usually, the amount of the anodic oxide film formed by the anodic oxidation treatment is preferably ¹ to 6 g / m ² .

After the anodizing treatment, a sealing treatment may be performed if desired. The sealing treatment is performed by a method of immersing the anodized aluminum plate in hot water or a hot aqueous solution containing an inorganic salt or an organic salt, or a method of exposing it to a steam bath.

After the anodizing treatment, if necessary, an interface control treatment such as a hydrophilic treatment may be performed. The interface control processing is described in U.S. Pat.
Examples thereof include an alkali metal silicate (for example, an aqueous solution of sodium silicate) as disclosed in JP-A-181461, JP-A-3280734, and JP-A-3902734. In this method, the lithographic printing plate support is immersed in an aqueous solution of sodium silicate or subjected to electrolytic treatment. Other than that,
Potassium fluoride zirconate disclosed in U.S. Pat. No. 22063, and U.S. Pat.
For example, a method of treating with polyvinyl phosphonic acid as disclosed in JP-A-153461 and JP-A-4689272 may be used.

For the details of each process described in the above items, known conditions can be appropriately adopted. In addition, the contents of documents cited in the present specification are referred to as the contents of the present specification.

As described above, the surface of the aluminum plate on which the photosensitive layer is provided is subjected to a surface treatment including at least a roughening treatment, while the back surface is subjected to an alkali etching treatment and a desmutting treatment. By the alkali etching treatment and the desmutting treatment, as shown in FIGS. 1 and 2, a grain-like pattern or a streak-like pattern is formed on the back surface, and in the planographic printing plate of the present invention obtained using the same, the aluminum plate used The rolling direction can be easily determined.

The alkali etching treatment on the back surface can be performed in the same manner as the above-described alkali etching treatment on the surface on which the photosensitive layer is provided. In particular, using an aqueous solution of caustic soda having a pH of 13 or more, the amount of aluminum dissolved is reduced to 0.1.
It is preferred to be 1 to 5 g / m ² . The backside desmutting treatment can be performed in the same manner as the above desmutting treatment for the surface on which the photosensitive layer is provided.
A method in which an acidic aqueous solution of not less than mass% is showered is preferable. After the alkali etching treatment and the desmutting treatment of the back surface, it is preferable to perform a water washing treatment.

The alkali etching treatment and desmutting treatment on the back surface may be performed separately from the surface treatment on the surface on which the photosensitive layer is provided, but it is preferable to perform them in the same step because the number of processing steps can be reduced. As a method of performing the alkali etching treatment in the same step, for example, a method of spraying an alkali aqueous solution on both sides of an aluminum plate in a shower or the like, or a method of dipping the aluminum plate by passing it through an alkaline aqueous solution bath is used. No. As a method of performing the desmut treatment in the same step, for example, a method of spraying an acid on both surfaces of an aluminum plate in a shower or the like can be mentioned. Further, it is preferable to perform the water washing after the alkali etching and the desmutting in the same step. For example, there is a method in which water is sprayed on both surfaces of an aluminum plate by spraying or the like.

As described above, a lithographic printing plate support is obtained. In order to obtain a lithographic printing plate of the present invention, a photosensitive agent may be applied to the surface and dried to form a photosensitive layer. The photosensitive agent is not particularly limited, and those usually used for photosensitive lithographic printing plates can be used. Then, by printing the image using a lith film, and performing a developing process and a gumming process, a printing plate that can be attached to a printing machine can be obtained. If a photosensitive layer having high sensitivity is provided, an image can be directly printed using a laser.

As the photosensitive agent, any photosensitive compound or a composition thereof whose solubility or swelling property in a developer changes before and after exposure can be used.
Hereinafter, typical ones will be described.

(A) Photosensitive layer composed of o-quinonediazide compound The photosensitive compound used in the positive photosensitive composition includes, for example, o-quinonediazide compounds.
-A naphthoquinonediazide compound is specifically exemplified.
The o-naphthoquinonediazide compound is disclosed in
An ester of 1,2-diazonaphthoquinone sulfonic acid chloride and pyrogallol-acetone resin described in -28403 is preferred. US Patent 3,04
Also preferred are the esters of 1,2-diazonaphthoquinonesulfonic acid chloride and phenol-formaldehyde resin described in US Pat. Nos. 6,120 and 3,188,210. Other known o-naphthoquinonediazide compounds can also be used.

Particularly preferred o-naphthoquinonediazide compounds are compounds obtained by reacting a polyhydroxy compound having a molecular weight of 1,000 or less with 1,2-diazonaphthoquinonesulfonic acid chloride. When synthesizing the o-naphthoquinonediazide compound, the reaction is performed such that 1,2-diazonaphthoquinonesulfonic acid chloride is in a ratio of 0.2 to 1.2 equivalents to 1 equivalent of the hydroxyl group of the polyhydroxy compound. Preferably, 0.3
More preferably, the reaction is performed so as to have a ratio of 1.0 to 1.0 equivalent. As the 1,2-diazonaphthoquinonesulfonic acid chloride, 1,2-diazonaphthoquinone-5-sulfonic acid chloride is preferable, but 1,2-diazonaphthoquinone-4-sulfonic acid chloride can also be used. Further, the obtained o-naphthoquinonediazide compound is a mixture of various substituents having different positions and introduction amounts of 1,2-diazonaphthoquinonesulfonyl chloride, but all the hydroxyl groups are 1,2-diazonaphthoquinonesulfonates. Of the mixture in the mixture converted to (content of completely esterified)
Is preferably at least 5 mol%, and 20 to 99 mol%
Is more preferable.

Further, as a photosensitive compound acting positively without using an o-naphthoquinonediazide compound, for example, an o-naphthoquinonediazide compound described in JP-B-56-2696 can be used.
A polymer compound having a nitrocarbinol ester group can also be used. Further, a combination system of a compound that generates an acid by photolysis and a compound having a —CO—C— group or a —CO—Si— group that dissociates by an acid can also be used. For example, a combination of a compound that generates an acid by photolysis with an acetal or an O, N-acetal compound (Japanese Patent Application Laid-Open No. 48-89003) and a combination with an orthoester or amide acetal compound (Japanese Patent Application Laid-Open No. 51-120714) Gazette), combinations with polymers having an acetal or ketal group in the main chain (JP-A-53-133429), combinations with enol ether compounds (JP-A-55-12995), N-acylimino carbon compounds (Japanese Unexamined Patent Publication No. Sho 55-126236), a combination with a polymer having an orthoester group in the main chain (Japanese Unexamined Patent Publication No. Sho 56-126236).
No. 17345), a combination with a silyl ester compound (JP-A-60-10247) and a combination with a silyl ether compound (JP-A-60-3754).
9, JP-A-60-112446).

The proportion of the positive-working photosensitive compound (including the above-mentioned combination system) in the photosensitive composition of the photosensitive layer is preferably 10 to 50% by mass.
More preferably, it is 15 to 40% by mass.

The o-quinonediazide compound alone can form the photosensitive layer, but is preferably used together with a resin soluble in alkaline water as a binder. Examples of resins soluble in alkaline water include novolak resins, and phenol-formaldehyde resins; m-cresol-formaldehyde resin, p-cresol-formaldehyde resin, m- / p-mixed cresol-formaldehyde resin, phenol / cresol ( Any of m-, p- and m- / p-mixtures may be used.)
Cresol-formaldehyde resins such as formaldehyde resins; phenol-modified xylene resins; polyhydroxystyrenes; polyhalogenated hydroxystyrenes; acrylic resins containing phenolic hydroxyl groups as disclosed in JP-A-51-34711; Various alkali-soluble polymer compounds such as an acrylic resin having a sulfonamide group and a urethane resin described in JP-A-2-866 can be contained. The alkali-soluble polymer compound has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 6.
000 is preferred.

The alkali-soluble polymer compound is contained in a proportion of not more than 70% by mass of the whole composition. Further, as described in U.S. Pat. No. 4,123,279, phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol-formaldehyde resin and octylphenol-formaldehyde resin, is used. The use of a resin obtained by polycondensation with formaldehyde is preferred in terms of improving the oil sensitivity of the image.

The photosensitive composition may contain a cyclic acid anhydride for improving the sensitivity, a printing-out agent for obtaining a visible image immediately after exposure, a dye or other filler as an image colorant, and the like. . Cyclic anhydrides are described, for example, in US Pat. No. 4,115,128, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy- △ ⁴ -Tetrahydrophthalic anhydride, tetrachlorophthalic anhydride,
Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, and pyromellitic anhydride are exemplified. The cyclic anhydride is added in an amount of 1 to the mass of the total composition.
Up to about 15% by mass can increase sensitivity up to about three times.

Examples of the printing-out agent for obtaining a visible image immediately after exposure include a combination of a photosensitive compound which releases an acid upon exposure and an organic dye which can form a salt. Specifically, for example, o described in JP-A-50-36209 and JP-A-53-8128 are disclosed.
A combination of a naphthoquinonediazide-4-sulfonic acid halogenide and a salt-forming organic dye;
No. 233, JP-A-54-74728, JP-A-60-3626, JP-A-61-143748, JP-A-61-151644, and JP-A-63-5
No. 8440 discloses a combination of a trihalomethyl compound and a salt-forming organic dye.

As a colorant for an image, a dye other than the above-mentioned salt-forming organic dye may be used. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and base dyes. Specifically, for example, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BO
S, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industries), Victoria Pure Blue,
Crystal violet (CI42555), methyl violet (CI42535), rhodamine B (CI4
5170B), malachite green (CI4200)
0) and methylene blue (CI52015). Dyes described in JP-A-62-293247 are particularly preferred.

The photosensitive composition is used by dissolving the above-mentioned components in a solvent capable of dissolving the same to form a solution on the lithographic printing plate support obtained above. The solvent is, for example,
Ethylene dichloride, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 1-methoxy-2-propanol,
-Methoxy-2-propyl acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, dimethylacetamide, dimethylformamide,
Water, N-methylpyrrolidone, tetrahydrofurfuryl alcohol, acetone, diacetone alcohol, methanol, ethanol, isopropanol, diethylene glycol, dimethyl ether. These may be used alone or as a mixture. The concentration (solid content) of each of the above components in the solution is 2 to 50% by mass. In addition, the amount of application varies depending on the application, for example, in the case of a photosensitive lithographic printing plate, generally, a solid content of 0.5 to
An amount of 3.0 g / m ² is preferable. The photosensitivity increases as the coating amount decreases, but the physical properties of the photosensitive film decrease.

The photosensitive composition may contain a surfactant, for example, a fluorine-based surfactant described in JP-A-62-170950, in order to improve coatability. The content of the surfactant is preferably 0.01 to 1% by mass of the whole photosensitive composition,
It is more preferably from 0.5 to 0.5% by mass.

(B) Photosensitive Layer Consisting of Diazo Resin and Binder Negative-acting photosensitive diazo compounds are described in US Pat. Nos. 2,063,631 and 2,667,4.
No. 15, diphenylamine-p which is a reaction product of a diazonium salt with an organic condensing agent having a reactive carbonyl group such as aldol or acetal.
-A condensation product of a diazonium salt and formaldehyde (a so-called photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are described in JP-B-49-480001.
JP, JP-B-49-45322, JP-B-49-45322
No. 45323, and the like. Since this type of photosensitive diazo compound is usually obtained in the form of a water-soluble inorganic salt, it can be applied as an aqueous solution. Further, a water-soluble diazo compound is prepared by the method described in Japanese Patent Publication No. 47-1167 with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both. After the reaction, a substantially water-insoluble photosensitive diazo resin which is a reaction product thereof can be used. The content of the diazo resin is preferably 5 to 50% by mass in the photosensitive layer. As the content decreases, the photosensitivity increases, but the stability over time decreases. The optimum diazo resin content is about 8-20% by weight.

On the other hand, various polymer compounds can be used as the binder. Among them, those having a functional group such as a hydroxyl group, an amino group, a carboxyl group, an amide group, a sulfonamide group, an active methylene group, a thioalcohol group, and an epoxy group are preferable. For example, shellac as described in GB 1,350,521, as described in GB 1,460,978 and US Pat. No. 4,123,276. Polymers containing a hydroxyethyl (meth) acrylate unit as the main repeating unit, polyamide resins described in U.S. Pat. No. 3,751,257 and described in British Patent 1,074,392. Phenol resins and polyvinyl acetal resins such as, for example, polyvinyl formal resins, polyvinyl butyral resins, US Pat. No. 3,660,0.
No. 97 linear polyurethane resin,
Phthalated resin of polyvinyl alcohol, epoxy resin obtained from bisphenol A and epichlorohydrin, polyaminostyrene and polyalkylamino (meth)
Examples include polymers containing an amino group such as acrylate, and cellulose derivatives such as cellulose acetate, cellulose alkyl ether, and cellulose acetate phthalate.

The composition comprising the diazo resin and the binder further comprises a pH indicator as described in GB 1,041,463, US Pat.
It can contain additives such as phosphoric acid and dyes described in US Pat. No. 6,646.

The thickness of the photosensitive layer provided on the lithographic printing plate support is preferably 0.1 to 30 μm.
More preferably, it is 10 to 10 μm. The amount (solid content) of the photosensitive layer is preferably from about 0.1 to about 7 g / m ² ,
More preferably, it is 0.5 to 4 g / m ² .

After the lithographic printing plate is image-exposed, a resin image is formed by a process including development by a conventional method. For example, in the case of a positive photosensitive lithographic printing plate having a photosensitive layer (A), after image exposure, as described in U.S. Pat. No. 4,259,434 and JP-A-3-90388. By developing with an alkaline aqueous solution, the photosensitive layer on the exposed portion is removed, and a printing plate is obtained. In the case of a negative photosensitive lithographic printing plate having a photosensitive layer (B) composed of a diazo resin and a binder, it is described in, for example, US Pat. No. 4,186,006 after image exposure. By developing with such a developing solution, the unexposed portion of the photosensitive layer is removed, and a printing plate is obtained. In the case of a negative photosensitive lithographic printing plate described in JP-A-5-2273 or JP-A-4-219759,
As described in these publications, development can be performed with an aqueous solution of an alkali metal silicate.

[0052]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. 1. Production of lithographic printing plate (Example 1) Using a twin-roll continuous casting machine, a thickness of 7
mm, and then cold-rolled to a thickness of 2 mm, heat-treated (annealed) at 480 ° C, and cold-rolled and straightened to a thickness of 0.24 mm. Then, a JIS1050 material was formed. On the cast upper surface of the obtained aluminum rolled plate, an alkali etching process, a desmutting process, an electrochemical graining process, and an anodizing process are sequentially performed, while the cast lower surface is a back surface, and an alkali etching process and a desmutting process are performed. A printing plate support was obtained. The alkali etching treatment and the desmut treatment on both surfaces were performed simultaneously.
The alkali etching of the back surface is performed by using an aqueous solution of sodium hydroxide having a pH of 13 and dissolving the aluminum in an amount of 1 g / m ^2.
It was given as. In the desmut treatment of the back surface, an acidic aqueous solution having a nitric acid concentration of 1% by mass was applied in a shower state, thereby removing the smut generated by the alkali etching treatment. After each treatment, a water washing treatment was performed. A photosensitive layer was provided on the roughened surface of the obtained lithographic printing plate support to obtain a lithographic printing plate of the present invention. A grain pattern appeared on the back surface of the obtained lithographic printing plate.

(Example 2) A lithographic printing plate of the present invention was obtained in the same manner as in Example 1, except that the upper surface of the obtained rolled aluminum plate was used as the casting upper surface. A grain pattern appeared on the back surface of the obtained lithographic printing plate.

(Example 3) A rolled aluminum plate having a thickness of 15 mm was formed using a twin-belt continuous casting machine and a hot rolling mill, and then cold-rolled to a thickness of 2 mm. After heat treatment (annealing) at ℃, cold rolling and straightening to a thickness of 0.24 mm,
JIS 1050 material was formed. With the casting lower surface of the obtained rolled aluminum plate as the back surface, the respective surfaces were subjected to each treatment and the photosensitive layer was provided in the same manner as in Example 1 to obtain a lithographic printing plate of the present invention. A streak pattern appeared on the back surface of the obtained lithographic printing plate.

Example 4 A lithographic printing plate of the present invention was obtained in the same manner as in Example 3, except that the upper surface of the rolled aluminum plate obtained was cast. A streak pattern appeared on the back surface of the obtained lithographic printing plate.

Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 1 except that the back surface was not subjected to the alkali etching treatment and the desmutting treatment.

Comparative Example 2 A lithographic printing plate was obtained in the same manner as in Example 2 except that the back surface was not subjected to the alkali etching treatment and the desmutting treatment.

(Comparative Example 3) A thickness of 50 was obtained by a DC casting method.
After forming a casting soul of 0 mm, the surface of the obtained ingot was shaved by an average of 10 mm using a facing machine, and then 550 ° C. for about 5 hours.
To perform a soaking process. When the temperature was lowered to 400 ° C., hot rolling was performed to a thickness of 3 mm, heat treatment was performed at 500 ° C. using a continuous annealing machine, and then cooling was performed to a thickness of 0.24 mm. Rolling
JIS 1050 material was formed. One side of the obtained rolled aluminum plate was used as a back surface, and the same process as in Example 1 was carried out on each side to provide a photosensitive layer to obtain a lithographic printing plate.

Comparative Example 4 A lithographic printing plate was obtained in the same manner as in Comparative Example 3, except that the back surface was not subjected to the alkali etching treatment and the desmutting treatment.

2. Visibility of Back Side Pattern The visibility of the back side pattern of the planographic printing plates of each of the examples and comparative examples was evaluated. If the pattern is clear and the rolling direction of the rolled aluminum plate can be determined, `` good ''; if the pattern is somewhat unclear but the rolling direction can be determined, `` good '' is slightly poor, but the pattern is unclear and the rolling direction is difficult to determine. "Poor".

The results are shown in Table 1. Since the lithographic printing plate of the present invention has a grain pattern or streak pattern on the back surface,
It turns out that it is excellent in visibility and it is easy to determine the rolling direction of the used rolled aluminum plate (Examples 1 to 4).
On the other hand, a lithographic printing plate having no grain pattern or streak pattern on the back surface is inferior in visibility (Comparative Examples 1 to 4).

[0062]

[Table 1]

[0063]

The lithographic printing plate of the present invention has a photosensitive layer on one side and a grain-like or streak-like pattern on the other side, so that the rolling direction of the aluminum rolled plate used can be determined. Because of its simplicity, vertical and horizontal recognition is not erroneous during plate-making work or installation work on a printing press, and the handleability is excellent. In particular, as an aluminum plate used for a lithographic printing plate support, an aluminum rolled plate obtained by twin roll continuous casting and cold rolling, or an aluminum rolled plate obtained by twin belt continuous casting, hot rolling and cold rolling. Use, when providing a grain pattern or streak pattern by alkali etching treatment and desmut treatment,
The number of manufacturing steps can be reduced, which is extremely useful.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of the back surface of a lithographic printing plate of the present invention having a grain pattern on the back surface.

FIG. 2 is a view showing an example of the back surface of the planographic printing plate of the present invention having a stripe pattern on the back surface.

[Explanation of symbols]

 1 Lithographic printing plate of the present invention having a grain pattern on the back surface 2 Lithographic printing plate of the present invention having a streak pattern on the back surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AB03 DA17 DA18 DA40 2H096 AA06 DA10 2H114 AA04 AA14 AA23 AA29 BA01 DA04 DA73 EA01 EA02 GA05 GA09

Claims (3)

[Claims] 1. A lithographic printing plate having a photosensitive layer on one side and a grain pattern or streak pattern on the other side. 2. The planographic printing plate according to claim 1, wherein a photosensitive layer is provided on the surface of the planographic printing plate support on which the roughening treatment has been performed, wherein the planographic printing plate support comprises: It is characterized in that at least one surface of a rolled aluminum plate obtained by twin roll continuous casting and cold rolling is subjected to a roughening treatment, and the other surface is subjected to an alkali etching treatment and a desmutting treatment to provide a grain pattern. Lithographic printing plate. 3. The lithographic printing plate according to claim 1, wherein a photosensitive layer is provided on the surface of the lithographic printing plate support on which the roughening treatment has been performed, wherein the lithographic printing plate support comprises: Twin belt continuous casting, at least one surface of a rolled aluminum plate obtained by hot rolling and cold rolling is subjected to a roughening treatment, and the other surface is subjected to an alkali etching treatment and a desmut treatment to provide a streak pattern. A lithographic printing plate characterized in that: