JP3009910B2 - Electrophotographic lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a printing plate having a photoconductive layer provided on a conductive support, wherein after forming a toner image by reversal development on an exposed portion by an electrophotographic method, a non-image portion photoconductive layer other than the toner image portion is provided. Electrophotographic lithographic printing for electrophotographic lithographic printing for making a printing plate by removing lithographic printing plates with good image resolution and the like, no background stains, and high printing durability Regarding the printing plate.

[Prior art and its problems]

In order to prepare a lithographic printing plate, for example, a plate making method in which a surface photosensitive layer of a printing plate precursor is directly exposed through an original to thereby form a cured portion and an uncured portion corresponding to an image portion and a non-image portion of the original, and A lithographic printing plate precursor is known as a lithographic printing plate precursor for this purpose, but a lithographic printing plate making use of electrophotographic technology, which has higher sensitivity than a method of making a lithographic printing plate by such exposure, is known. The method is also widely used, and lithographic printing plates for this purpose are also manufactured. Conventionally, as a printing plate utilizing the principle of electrophotography, for example,
No. 47610, No. 48-4002, No. 48-18325, No. 51-15766
Zinc oxide described in JP-A-51-25761 and the like.
A resin-dispersed offset printing master is known. In such an offset printing master, a toner image is formed by using an electrophotographic method, and then a non-image portion other than the toner image portion is insensitive to oil. Used as a printing plate by processing. However, these printing plates have poor printing durability because the image portion is formed only of toner particles, and the number of prints by this original plate is limited to about 5000 to 10000 sheets, and more Not suitable for printing. In addition, in order to perform the above desensitization treatment, it is necessary to use an acidic solution such as a hexacyanoiron salt, which has problems in pollution control and occupational health. Also, JP-B-37-17162, JP-B-38-7758, JP-B-46-394
No. 05, JP-A-52-2437, JP-A-57-161863, JP-A-58-2854
JP-A-58-28760 and JP-A-58-118658 disclose a printing plate having an organic photoconductor held in a resin, for example, oxazole or oxadiazole-based photoconductor made of styrene / maleic anhydride. An electrophotographic lithographic printing plate is disclosed in which a photoconductive layer bound with a resin such as an acid copolymer is provided on a grained aluminum plate. In these general plate making methods, after a toner image is formed by an electrophotographic image forming method, a non-image portion other than the toner image portion is treated with a solution containing an alkali agent or the like, so that a non-image portion is formed on the plate. Dissolves the so-called photoconductive layer (so-called elution), and more generally removes the excess eluate and the solubilized photoconductive layer from the plate with a water washing solution having a pH of neutral or higher. Plate making is performed by applying a plate surface protecting solution (protective gum solution) accordingly. In the plate making method according to this method, the image portion includes not only the toner image portion but also the photoconductive layer under the toner image portion. Even if the toner image portion is worn, the photoconductive layer retains the function of the image portion. Excellent in nature. For these, a processing solution containing an organic solvent such as ethylene glycol, glycerin, isopropyl alcohol, or benzyl alcohol is used for removing the photoconductive layer in the non-image area. On the other hand, lithographic printing plates in which the photoconductive layer in the non-image area can be removed with an alkaline aqueous solution containing no organic solvent are disclosed in JP-A-54-134632, JP-A-55-165254, JP-A-59-12452, and JP-A-59-12452.
No. 9-49555. The main components of the lithographic printing plate described in these publications are, for example, anodized aluminum which is grained with a photoconductive layer made of a photoconductive pigment such as copper phthalocyanine and an alkali-soluble resin such as phenol resin. The lithographic printing plate is provided on a plate, and has the following advantages. High sensitivity. It has color sensitivity over the entire visible range and can record images with white light and a He-Ne laser or a semiconductor laser that oscillates in the near infrared region. A photoconductive layer that can be easily dissolved in an alkaline aqueous solution containing no organic solvent is obtained. Excellent electrophotographic properties such as charge storage and moisture resistance. Excellent stamping resistance. And so on. As a result of further studies on this lithographic printing plate having these various advantages, if the surface roughness of the conductive support in these lithographic printing plates is too large, halation is likely to occur, and the image resolution and sharpness Not only is it undesirable from the point of plate making such as the degree, but the elution of the non-image area is not completely performed, so that an elution failure called so-called pigment residue occurs, and when used as a printing plate, it is said that printing background stains occur. It has been found that this has an unfavorable adverse effect on printability. It has also been found that, if the surface roughness of the lithographic printing plate conductive support is too small, the adhesion of the photoconductive layer to the support is insufficient, resulting in insufficient printing durability. The present invention further examines the surface roughness of the surface of the photoconductive layer provided on the conductive support and the relationship with that of the conductive support. As a result, if the surface roughness of the surface of the photoconductive layer is absolutely large, Irrespective of the surface roughness of the conductive support, similarly to the above, adversely affects image reproducibility such as toner image resolution, etc., and poor plate making / printing such as poor elution, and conversely, the photoconductive layer surface roughness is too small. For example, if the coating liquid for the photoconductive layer is low-viscosity and has high affinity with the printing plate support and is dried under mild conditions, the valley of the printing plate support is sufficiently filled with the coating liquid, and the photoconductive layer surface Is highly smooth, but from the above-mentioned reason, due to the provision on the conductive support having a specific surface roughness, the photoconductive layer itself has a thickness unevenness microscopically, such as the charging potential. Electrophotographic characteristics and the elution from the side of the photoconductive layer The unevenness of the image line due to the inflow of the effluent causes unevenness.On the contrary, if the smoothness of the photoconductive layer surface is improved by remarkably increasing the viscosity of the photoconductive layer coating solution, the valley of the printing plate support is It was found that the coating liquid was not filled and the adhesion between the photoconductive layers of the support was insufficient.

[Object of the invention]

An object of the present invention is to prevent halation in an electrophotographic lithographic printing plate in which a photoconductive layer comprising at least a binder resin and an organic photoconductive compound is provided on a conductive support. An object of the present invention is to provide an electrophotographic lithographic printing plate from which a printing plate having good sharpness can be obtained. It is another object of the present invention to provide an electrophotographic lithographic printing plate having a high printing durability, free from soiling of printed matter, and capable of obtaining a printing plate with good water retention.

[Means for achieving the purpose]

 The object of the present invention is to provide at least an organic photoconductive compound
A photoconductive layer consisting of and a binder resin is provided on a conductive support.
Lithographic printing plate.
The toner image is formed by trans-development,
Non-image area photoconductive layer other than toner image area by contact with liquid
To form a lithographic printing plate
In this, the center line average roughness of the photoconductive layer side surface of the conductive support
Sa (Ra₁) Is 0.3 to 0.8 μm and the surface of the photoconductive layer is
Center line average roughness (Ra_Two) And the ratio [Ra_Two/ Ra₁Is 1/6 ~ 1/2
This is achieved by forming a surface shape. The electrophotographic lithographic printing plate according to the present invention will be described in detail.
Before clarification, the surface roughness will be described. Surface roughness refers to the three-dimensional unevenness of one cross-sectional shape.
Used to express algebra from points, cross section curves, roughness curves
Shows properties obtained from the line. Here, the section curve is
When cut on a plane perpendicular to the measurement surface,
This is the contour to be created. This cutting should be performed on the surface unless otherwise specified.
Cut in the direction where roughness appears most. For example, the direction
On the surface to be measured that has, cut at right angles to the direction. Surface roughness can be measured by the stylus method, topographer, light
Cutting, interferometry, scene gloss, light scattering, lasers
Speckle, white light speckle, porographic interference, interference
By various measurement methods such as fringe contrast and capacitance method
Required, the surface of the conductive support photoconductive layer side according to the present invention.
And the surface shape of the photoconductive layer surface depends on the scanning length and surface roughness.
Measured with a stylus-type contact-type device in consideration of the level
The numerical value of the case shall be adopted. Type that directly reads center line average roughness, number of peaks per unit length, etc.
The stylus-type surface roughness measuring device eliminates so-called surface waviness components.
To remove long and middle wavelength components
An electric filter is included. Therefore, the sectional curve
Using a different curve (called a roughness curve)
The average core wire roughness is directly indicated. The center line average roughness Ra is calculated from the extracted curve
In the direction of the measurement length L
The center line is the X axis, the direction of the vertical magnification is the Z axis, and the extraction curve is Z =
When represented by f (x), given by the following equation,
Is displayed. Ra = 1 / L∫_o ^L| f (x) | dx (μm) That is, Ra is the part of the area surrounded by the extraction curve and the center line.
Represents the standard deviation of the area divided by the measured length. The center line average roughness Ra in the present invention is JI as in the above equation.
It is defined by SB0601, and in the present invention
Value 0.08mm, measurement length 0.5mm, scanning speed 0.06mm / sec
The value measured under the following conditions is adopted. Next, the electrophotographic lithographic printing plate according to the present invention will be described in detail.
This will be described in detail. The electrophotographic lithographic printing plate according to the present invention comprises a conductive support.
Contains at least organic photoconductive compound and binder resin
Then, a toner image is formed by a normal electrophotographic developing method.
What you get. As the conductive support used in the present invention, a conductive table
Plastic sheet with surface, impermeable and conductive
Paper or aluminum, zinc, copper-aluminium
Bimetals such as copper, stainless steel, chrome-copper,
Copper-aluminum, chrome-lead-iron, chromium-copper-
Hydrophilic treatment of metal plate such as trimetal such as stainless steel
Examples include a conductive support having a surface. Their thickness
Is preferably 0.07 to 2 mm, more preferably 0.1 to 0.5 mm. this
Among these supports, aluminum plates are preferably used.
You. This aluminum plate is mainly composed of aluminum
May contain trace amounts of foreign elements
Can be used as appropriate. The conductive support according to the present invention is at least as necessary.
Also, the surface on which the photoconductive layer is to be
Center line average roughness (Ra₁) From 0.3 to 0.8
μm. The surface processing method is known
Methods such as graining and anodizing can be used.
You. Prior to the graining treatment, if necessary, a surfactant may be added.
Or a degreasing treatment with an alkaline aqueous solution. Graining
Methods include mechanical graining, electrochemical graining, and chemical graining.
Surface selective dissolution method and the like. Mechanical surface roughening method
Polishing method, brush polishing method, blast polishing method, buff polishing method
And other known methods can be used. Also electrochemical
The surface roughening method uses AC or DC in hydrochloric acid or nitric acid electrolyte.
There is a better way. Also, JP-A-54-63902
As disclosed in the above, a method combining the two can be used. In the present invention, the water retention of the surface of the support is improved,
Is to create a dense, even grain that is deeper than
In particular, electrochemical surface roughening method using electrolytic solution mainly composed of mineral acid
Is preferred. The grain depth is disclosed, for example, in Japanese Patent Publication No. 55-34240.
Arbitrarily set within a specific range by controlling the electrolysis conditions etc.
Can be determined. The aluminum plate roughened in this way can be
And use after alkali etching and neutralization. The anodized aluminum plate after the above treatment
Is done. The electrolyte used for the anodizing treatment is sulfuric acid.
Acid, phosphoric acid, oxalic acid, etc. or their mixed acids
Depending on the type of electrolyte.
It is determined as appropriate. Anodizing conditions depend on the electrolyte used.
Although it cannot be specified unambiguously because it changes more drastically,
The electrolyte concentration is 1.0 ~ 80% by weight, the liquid temperature is 5.0 ~ 70 ℃, and the current
Density is 5.0-60A / dm^Two, Voltage is 1.0 ~ 100V, electrolysis time is 10
It only has to be in the range of ~ 3000 seconds. The yang obtained in this way
Extreme oxide film amount is 0.1-10g / m^TwoIs good, and 1.0-6.0g /
m^TwoIs suitable. Further, as described in JP-B-47-5125, anodic oxidation
After treatment, it is also preferable to treat with an aqueous alkali metal silicate solution.
Suitable. Also described in U.S. Pat.
Silicate electrodeposition is also effective. West German Patent No. 1621478
The treatment with polyvinyl sulfonic acid described in
is there. The center line average roughness of 0.3 to 0.8 μm obtained in this way
Surface shape of the conductive support having the
More preferably, the bearing length specified in ISO 4287/1
Surface (Rtp) is desirably a rough surface of 70 to 85%.
Bare as a support for an electrophotographic lithographic printing plate according to the present invention
When the ring length is less than 70%, the support of the photoconductive layer
The anchoring effect on the halves, and conversely the bearing length
If it exceeds 85%, photoconductivity will be generated in the recess on the surface of the support during elution
The possibility that the layer remains without being removed increases, and
Dirt is easily induced. More preferred bearing length
The range is 73-82%. Adhesion and electron transfer between the conductive support and the photoconductive layer
Casein, polyvinylidene as necessary to improve the true characteristics
Alcohol, ethyl cellulose, phenolic resin,
Tylene / maleic anhydride copolymer, maleic acid / acrylic
Acrylic acid copolymer, acrylic acid / methacrylic acid copolymer,
Liacrylic acid, polymaleic acid, poly-α-hydroxy
Acrylic acid, polyitaconic acid, and their polymer electrolytes
Alkali metal and / or ammonium salts of ethanol
Amino alcohols such as ruamine and ethylenediamine,
Amines such as propanediamine and triethylenetetramine
And their organic salts such as hydrochloride, phosphate and oxalate
Ammonium salts, inosit hexaphosphate, etc.
Phosphate esters and salts thereof, malic acid, citric acid, and
Hydroxycarboxylic acids such as tartaric acid, and salts thereof, or
Are monoaminocarboxylic acids such as glycine, alanine, etc.
Phosphorus, threonine, dihydroxyethylglycine, etc.
S-amino acids such as xy amino acids, cysteine and cystine
Monoaminodica such as acid, aspartic acid and glutamic acid
Diaminomonocarboxylic acids such as rubonic acid and lysine;
Droxyphenylglycine, phenylalanine, ant
Aromatic amino acids such as lanic acid, tryptophan,
Amino acids having a heterocyclic ring such as
Aliphatic amino sulfones such as rohexyl sulfamic acid
Acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, imino
Diacetate, hydroxyethylethylenediamine triacetic acid, di
(Hydroxyethyl) ethylenediamine diacetate, ethyl
Diamine diacetate, diethylene triamine pentaacetic acid, tri
(Poly) aminopoly vinegar such as ethylene tetramine hexaacetic acid
Acid, aminotri (methylenephosphonic) acid, 1-hydroxy
Sethylidene-1,1-diphosphonic acid, ethylenediamine
Tetra (methylene phosphonic acid), hexamethylene diamine
Tetra (methylene phosphonic acid), diethylene triamid
(Poly) aminopoyl such as penta (methylenephosphonic acid)
Li (methylenephosphonic acid) and its analogues, and these
At least a part of the acid groups of the compound is an alkali metal salt or an alkali metal salt.
An intermediate layer made of a ammonium salt or the like may be provided. A known electronic photograph is formed on the conductive support thus obtained.
By providing a photoconductive layer, an electrophotographic photoreceptor can be obtained.
You. As a photoconductive material used for the photoconductive layer according to the present invention
Can be a known organic compound. Examples of the organic photoconductive material include: a) Triazolone described in US Pat. No. 3,112,197.
B) Oxadia described in US Pat. No. 3,189,447.
Sol derivatives, c) imidazole derivatives described in JP-B-37-16096 and the like.
Conductors; d) U.S. Pat. Nos. 3,542,544, 3,615,402, 3,820,089
Specification, JP-B-45-555, JP-B-51-10983, JP-A-51-983
No. 93224, No. 55-108667, No. 55-156953, No. 56-366
E) US Pat. Nos. 3,180,729 and 4,278,746;
No. 55-88064, No. 55-88065, No. 49-105537, No. 55-
51086, 56-80051, 56-88141, 57-45545
Nos. 54-112637 and 55-74546.
Lazoline derivatives and pyrazolone derivatives, f) US Pat. No. 3,615,404, JP-B-51-10105,
Nos. 46-3712, 47-28336, JP-A-54-83435,
54-1110836, phenyle described in 54-119925 and the like
G) U.S. Patent Nos. 3,567,450, 3,180,703 and 3,240,597
No. 3658520, No. 42322103, No. 4159661, No. 40123
No. 76, West German Patent (DAS) 1110518, Japanese Patent Publication No. 49-
No. 35702, No. 39-27577, JP-A-55-144250, No. 56-
No. 119132, No. 56-22437, etc.
H) amino-substituted carboxylic acids described in US Pat. No. 3,352,501.
Con derivatives; i) N, N-bicals described in U.S. Pat. No. 3,542,546
Basil derivatives; j) Oxazones described in US Pat. No. 3,257,203
K) styryl ant described in JP-A-56-46234, etc.
Helix derivatives, 1) fluorenone derivatives described in JP-A-54-110837, etc.
Conductors, m) U.S. Pat. No. 3,717,462, JP-A-54-59143
(Corresponding to U.S. Patent No. 4150987), 55-52063, 55
-52064, 55-46760, 55-85495, 57-113
No. 50, No. 57-1448749, No. 57-104144, etc.
Hydrazone derivatives, n) U.S. Pat. Nos. 4,047,948, 4,047,949, 4,265,990
Nos. 4273846, 4299897, 4306008, etc.
O) JP-A-58-199093, JP-A-59-95540, and JP-A-59-97148.
Nos. 59-195658 and 62-36674.
Tilbene derivatives, p) polyvinylcarba described in JP-B-34-10966
Sol and its derivatives; q) Possible compounds described in JP-B-43-18674 and JP-B-43-19192.
Rivinylvinylene, polyvinylanthracene, poly-2-
Vinyl-4- (4'-dimethylaminophenyl) -5
Phenyloxazole, poly-3-vinyl-N-ethyl
Vinyl polymers such as carbazole, and r) polyacenaphthyl described in JP-B-43-19193.
, Polyindene, acenaphthylene / styrene copolymer
S) pyrene / form described in JP-B-56-13390, etc.
Aldehyde resin, ethyl carbazole / formaldehyde
Condensed resins such as resin, t) described in JP-A-56-90883 and JP-A-56-161550
U) U.S. Pat. Nos. 3,397,086 and 4,466,802;
Nos. 44-121611, 46-30035 and 49-17535,
49-11136, 51-90827, 52-655643, 57-
Nos. 148745, 64-2061 and 64-4389
Metal-free or metal (oxide) phthalocyanine and naphthalo
Cyanine and its derivatives. The organic photoconductive compound according to the present invention includes a) to
Not limited to the compounds listed in u),
Organic photoconductive compounds can be used and these
Two or more organic photoconductive compounds may be used in combination, if desired.
In the present invention, it is possible to
Phthalocyanine is used to advantage
Can be. As phthalocyanines, α, β, γ, π, χ, and
ε-type metal-free phthalocyanine, or copper, cobalt, lead,
Metal phthalocyanine such as zinc or titanyl phthalocyanine
Nin is preferred. In particular, electrophotographic characteristics such as sensitivity and dark decay
As a photoconductive compound for electrophotographic lithographic printing plates,
Also suitable phthalocyanine is χ type metal-free phthalocyanine
It is. It also improves the sensitivity of the photoconductor and increases the sensitivity in the desired wavelength range.
Various pigments, dyes, etc. are used together for the purpose of holding
You can do it. Examples of these are: 1) U.S. Pat. Nos. 4,436,800 and 4,439,506;
47-37543, 58-123541, 58-192042, 58
-219263, 59-78356, 60-179746, 61-1
No. 48453, No. 61-238063, No. 60-5941, No. 60-4
Monoazo, bisazo, trisazo described in No. 5664
Pigments, 2) described in U.S. Pat. Nos. 3,397,086 and 4,668,802
Metal phthalocyanine or non-metal phthalocyanine
Tarocyanine pigments, 3) perylene-based compounds described in US Pat.
Pigments, 4) indigo described in British Patent No. 2237680 and the like,
Thioindigo derivatives, 5) quinacride described in British Patent No. 2237679 and the like
6) British Patent No. 2237678, JP-A-59-184348
And polycyclic quinone pigments described in JP-A-62-28738, 7) Bisbenziimi described in JP-A-47-30331 and the like.
Dazole pigments, 8) described in US Pat. Nos. 4,396,610 and 4,644,082.
9) Squarium salt pigments described in 9) JP-A-59-53850 and JP-A-61-212542.
Azurenium salt pigments. In addition, as sensitization fee, “Electrophotography”
73), “Synthetic Organic Chemistry” 24 No.11 1010 (1966)
And the like. Examples include 10) Applied Optics Supplement 350 (1969),
Triarylmethanes described in, for example, Japanese Patent Application Laid-Open No. 50-39548
Dyes, 11) cyanine compounds described in US Pat. No. 3,597,196, etc.
Dyes 12) JP-A-59-164588, JP-A-60-163047, JP-A-60-252517
And the like. These sensitizing dyes may be used alone or in combination of two or more.
May be. The photoconductive layer according to the present invention has a
Nitrofluorenone, chloranil, tetracyanoethylene
Compounds such as JP-A-58-65439 and JP-A-58-102239,
Nos. 58-129439, 60-71965, etc.
Can be used in combination. In the photoconductive layer for an electrophotographic lithographic printing plate according to the present invention
Consists of at least an organic photoconductive compound and a binder resin.
You. This electrophotographic photoconductive layer finally becomes the non-image area photoconductive
The layer needs to be removed, but this step
Solubility in Solution and Resist for Eluent of Toner Image
Determined by the relative relationship with the
However, at least as a binder resin,
A soluble or dispersible polymer compound is preferred. A specific example is styrene / maleic anhydride copolymer.
Body, styrene / maleic acid monoester copolymer, meta
Crylic acid / methacrylic acid ester copolymer, styrene /
Methacrylic acid / methacrylic acid ester copolymer, acrylic
Luic acid / methacrylic acid ester copolymer, styrene /
Lylic acid / methacrylic acid ester copolymer, vinyl acetate /
Crotonic acid copolymer, vinyl acetate / crotonic acid / methacrylic acid
Styrene and methacrylic acid such as acrylate copolymers
Stele, acrylate, vinyl acetate, benzoic acid bicarbonate
And acrylic acid, methacrylic acid, itaconic acid,
Tonic acid, maleic acid, maleic anhydride, fumaric acid, etc.
Copolymerization with monomer containing rubonic acid or monomer containing acid anhydride group
Coalescence, methacrylamide, vinylpyrrolidone,
Roylmorpholine, phenolic hydroxyl group, sulfonic acid
Having a group, a sulfonamide group or a sulfonimide group
Copolymer containing phenol, phenol resin, partially saponified vinegar
Vinyl acid resin, xylene resin, polyvinyl butyral, etc.
Vinyl acetal resin of the above. Monomer containing monomer having acid anhydride group or carboxylic acid group
The coalesced and phenolic resin are
Charge holding power is high, and
Can be. Examples of the monomer-containing copolymer having an acid anhydride group include
A copolymer of styrene and maleic anhydride is preferred. Cal
As a monomer-containing copolymer having a boric acid group, styrene
Of acrylic acid and maleic acid monoester, acrylic acid
Or methacrylic acid and their alkyl esters,
And aralkyl esters.
Polymers are preferred. Good vinyl acetate and crotonic acid
No. A particularly preferred phenolic resin is
Knol, o-cresol, m-cresol, or p-
Resol and methanal or ethanal under acidic condition
And a novolak resin condensed with the above. Conclusion
The resin may be used alone or as a mixture of two or more.
No. When using only the photoconductive compound and the binder resin,
If the content of the photoconductive compound is small, the sensitivity becomes low,
Photoconductive compound (P) is P / B with binder resin (B)
1/20 or more, more preferably 1/6 or more (weight conversion)
It is preferable to use them in combination. However, binding
Even if the content of the photoconductive compound is too large relative to the resin,
Not only is the sensitivity not expected to increase compared to the increase in
As it becomes impossible to balance with electrophotographic characteristics, etc.
Mixing ratio (P / B) of resin and photoconductive compound is 1/6 to 1/3
Range is desirable. If the photoconductive layer is too thin,
ー Electricity required for development cannot be charged, conversely if it is too thick, it will elute
In addition to accelerating the deterioration of the solution, a side etch
0.10 ~ 30μm because good image cannot be obtained by inducing
However, it is more preferably 0.5 to 10 μm. The electrophotographic lithographic printing plate according to the present invention is prepared according to a standard method.
It is obtained by coating a photoconductive layer on a conductive support. Photoconductive
When making the layers, the components that make up the photoconductive layer are the same
Layer, or separated into two or more layers.
Methods such as charge carrier generation material and charge carrier transport
There are known methods for separating substances into different layers and using them.
Alternatively, it can be created by any method. Coating liquid
Is to dissolve each component of the photoconductive layer in a suitable solvent
Create, but when using components that are insoluble in solvents such as pigments,
Ball mill, paint shaker, dyno mill, attra
Average particle diameter of 0.01 to 5 μm using a disperser such as
Preferably, it is used by dispersing it at 0.05 to 0.2 μm. Photoconductive layer
Binder resin and other additives used for dispersion of pigments, etc.
Alternatively, it can be added after dispersion. Create in this way
Spin coating, blade coating, knife coating,
Bar roll application, dip application, rod bar application,
Known methods such as play coating and extrusion coating
Coating on a support and drying to obtain an electrophotographic lithographic printing plate
Can be. As a solvent for the coating solution, dichloromethane,
Halogenated hydrocarbons such as dichloroethane and chloroform
, Methanol, ethanol, 2-propanol, 1-
Alcohols such as butanol, acetone, 2-butano
Ketones such as cyclohexane and cyclohexanone, 2-methoxyethane
Glycols such as knol and 2-methoxyethyl acetate
Rings of ethers, oxolane, oxane, dioxane, etc.
Ethers, esters such as propyl acetate and butyl acetate
Electrophotographic lithographic printing according to the present invention.
Particularly preferred as a solvent (dispersion medium) for the photoconductive layer of the plate
Is at least one of nitrogen and oxygen atoms in the solvent molecule
Having 2 or more atoms, dissolving 5% by weight or more of water, and
(25 ° C.) is 0.95 or more. this
Examples of such solvents include 2-methoxyethanol, formic acid
Methyl, 2-ethoxyethyl acetate, 2- (2-E
Toxiethoxy) ethanol, aetamide, morpholy
, N-methylformamide, 2- (2-ethoxyethoxy)
B) Ethyl acetate, 2-methoxyethyl acetate
G, 1,3-butanediol, 2- (2-methoxyethoxy)
B) ethanol, ethyl lactate, 1-methyl-2-pyrroli
Dinone, 1,4-dioxane, 1,2-propanediol, 2
-Oxolanmethanol, 1,3-propanediol,
Ethyl anoacetate, methyl acetoacetate, ethylene glycol
Recall diacetate, 2-pyrrolidinone, 1,2-eta
Diol, diethylene glycol, γ-butyrolact
And 2-furanmethanal. The photoconductive layer according to the present invention may have photoconductive
In addition to the compound and the binder resin, the flexibility of the photoconductive layer, the coating surface, etc.
Plasticizers, surfactants, and
Other additives can be added. Biphenyl is a plasticizer
, Biphenyl chloride, o-terphenyl, p-terphe
Nil, dibutyl phthalate, dimethyl glycol phthale
Salt, dioctyl phthalate, triphenyl phosphate, etc.
No. In the present invention, the electrophotographic properties, printability, and photoconductivity
The surface roughness of the photoconductive layer depends on the adhesion resistance between the layer and the back of the printing plate.
(Center line average roughness: Ra_Two) Is 0.05-0.4μm, more preferred
Or the coating solution viscosity (solids concentration) to be in the range of 0.1 to 0.3 μm
It is desirable to select a coating method and the like.
Furthermore, the center line average of the surface of the conductive support on which the photoconductive layer is provided
Roughness (Ra₁) And the ratio [Ra_Two/ Ra₁] Is 1/6 ~ 1/2, more preferred
A good range is 1/6 to 1/3. The electrophotographic lithographic printing plate used in the present invention is as described above.
It is manufactured by a known operation using an electrophotographic photosensitive member.
Can be. That is, the image is charged substantially uniformly in a dark place,
An electrostatic latent image is formed by exposure. Exposure methods include
Senon lamps, tungsten lamps, fluorescent lamps, etc.
And reflection image exposure, contact exposure through transparent positive film
And scanning exposure with laser light, light emitting diode, etc.
Can be When performing scanning exposure, use He-Ne laser, He-
Cd laser, argon ion laser, krypton ion laser
Laser, ruby laser, YAG laser, nitrogen laser, dye laser
Laser, excimer laser, GaAs / GaAlAs, InGaAsP
Semiconductor laser, alexandrite laser, copper vapor laser
Scanning exposure using a laser light source such as a laser, or a light emitting diode.
Scanning exposure using a liquid crystal shutter (light emitting diode
Line printer using array, liquid crystal shutter array, etc.
Light source). Next, the electrostatic latent image is developed with toner. developing
Methods include dry development (cascade development, magnetic brush
Use both liquid development and liquid cloud development)
I can do it. In particular, liquid development produces fine toner images.
This is suitable for producing a printing plate with good reproducibility. Change
In addition, positive / positive development by positive development and appropriate bias voltage
Negative / positive development by reversal development under application of pressure is also possible.
You. The formed toner image is subjected to a known fixing method, for example, heating.
It can be fixed by fixing, pressure fixing, solvent fixing and the like. Like this
The non-image area light guide
The printing plate can be prepared by removing the electric layer with an eluent. The toner according to the present invention is a resist
It is necessary to contain a resin component having
You. Examples of the resin component include methacrylic acid and methacrylic acid.
Acrylic resin composed of luic acid ester, vinyl acetate
Fat, vinyl acetate and ethylene or vinyl chloride, etc.
Coalescence, vinyl chloride resin, vinylidene chloride resin, polyvinylidene
Vinyl acetal resin such as rubutyral, polystyrene
Styrene, butadiene, methacrylate, etc.
Copolymer, polyethylene, polypropylene and salts thereof
Compound, polyethylene terephthalate, polyethylene iso
Polycarbonate of phthalate and bisphenol A
Polyester resin such as
Polyamide resin such as tylene adipamide, phenol resin
Fat, xylene resin, alkyd resin, vinyl-modified alkyd
Resin, gelatin, carboxymethyl cellulose, etc.
Cellulose ester derivatives, other waxes, waxes, etc.
I can do it. Does not adversely affect development / fixing of toner
Within the range, a dye or a charge control agent can be contained. The electrophotographic lithographic printing plate after toner development is
The image acts as a resist to form the photoconductive layer in the non-image area.
A printing plate can be prepared by processing with a plate processing solution. The plate-making processing solution and the processing method according to the present invention are described below.
It is described. Elution for dissolving and removing the non-image area photoconductive layer according to the present invention
As the liquid, any solution that at least solubilizes the binder resin
A solution can be used and is not particularly limited, but is preferably used.
Or those containing an alkaline agent and having a buffer capacity are desirable.
No. As the alkaline agent, the general formula SiO_Two/ M_TwoO (M = Na,
Silicates, alkali metal hydroxides, phosphorus represented by K)
Inorganic such as alkali metal and ammonium salts of acids and carbonic acids
Alkaline agents, ethanolamine, propanediamine, etc.
Organic alkali agents such as amines, and mixtures thereof
In particular, the above silicates show strong buffering capacity.
Therefore, it is advantageously used. Alkali gold is prescribed for this
It is desirable to add a metal hydroxide. In the eluate according to the present invention, the eluate is applied to the surface of the photoconductive layer.
Of the wettability of the water and the corresponding elution ability and elution treatment
It is preferable to include a surfactant for expanding conditions.
No. Examples of preferred surfactants include alkylbenzenes
Sulfonates (the alkyl group has 8 to 18 carbon atoms;
More preferably 12 to 16), alkylnaphthalenesulfonic acid
Salts (the alkyl group has 3 to 10 carbon atoms) naphthalenesul
Formalin condensate of phonic acid, dialkyl sulfosuccinic acid
Salts (the alkyl group has 2 to 18 carbon atoms);
Midosulfonates (the alkyl group has 11 to 17 carbon atoms)
And other anionic surfactants, imidazoline derivatives,
Boxybetaines, aminocarboxylic acids, sulfobetai
, Aminosulfates, imidazolines, etc.
Surfactants. The eluate further includes ions described in JP-A-55-25100.
Water-soluble compounds described in JP-A-55-95946
Nick Polymer, a water-soluble polymer described in JP-A-56-142528.
Neutral polymer electrolyte, neutral described in JP-A-58-75152
Salts, chelating agents described in JP-A-58-190952,
No. 1-177541, a liquid viscosity modifier described in JP-A-62-2266.
No. 57 preservatives and bactericides, U.S. Pat.
No. 3,545,970, British Patent No. 1382901, No. 1387713
Antifoaming agents described in the description etc., and natural and synthetic water-soluble poly
It can contain known components such as
You. The solvent in the eluate is a stable dispersion of the above components
Although there is no particular limitation as long as it can be performed, water is more preferable.
Preferably, ion-exchanged water is used advantageously. Also,
To stabilize the above components or adjust the elution rate
For this purpose, an appropriate amount of an organic solvent may be contained. In particular, when using the above silicate in an alkali agent, Si
O_Two/ M_TwoO = 0.5 to 8.5 (mole conversion) is preferable. Eluate pH
Is preferably 11.5 to 14.0, more preferably 12.0 to 13.5.
In the case of several plates or pH fluctuation over time,
It is desirable to improve the elution activity by adding a filler solution as needed
New The washing solution that can be used in the present invention is an excess eluate
And the solubilized photoconductive layer can be quickly diffused and dissolved in the liquid.
It has high performance. In the washing liquid, at least
Finalize compounds with acid dissociation index (pKa) between 7.0 and 10.5
To maintain the pH at 10.5 or less.
Good. This compound (hereinafter, unless otherwise specified, is washed with water
The acid dissociation index (pK
The compound having a) is simply referred to as a compound. )
At first, even water that does not contain compounds
Since it can be sufficiently washed with water, it is first used as a washing liquid.
Use a liquid that does not contain the compound and add
It may be contained in the washing solution or added to the washing solution prior to plate making.
It may be added. In the case of the former (post-addition), start adding
PH of the washing solution is 8.5-10.5, more preferably 9.5-10.0
Range is desirable. Also, especially if the plate size is constant,
Unless the area of the non-image part (eluted part) does not greatly differ,
Since the pH rise of the washing solution is almost proportional to the amount of printing (number of sheets),
It is not possible to add the compound according to the present invention every fixed number of sheets.
come. In the case of the latter (addition first), many
It can be further added as the pH of the washing solution increases. Also, for plate making
When adding a compound beforehand, add the compound alone
May be used, or one that has been previously dispersed or dissolved in water
May be. When preparing an aqueous solution, use a small amount of organic solvent.
To promote dissolution. Especially when the compound is a water-soluble solid
If so, immerse it in the washing tank,
It may be dissolved gradually due to flow or pH fluctuation.
No. The pH of the washing solution must always be below 10.5
However, at least in the compound-containing washing solution, 7.5 to 10.5
Should be kept in the range, more preferably in the range of 8.0 to 10.0
Is desirable. Compounds to be added to the washing solution have an acid dissociation index (p
Ka) with multiple dissociation stages depending on the compound
In some cases, at least one of the acid dissociation indices (pKa)
Should be between 7.0 and 10.5. 7. The acid dissociation index (pK
Examples of the compound having a) include, for example, "Chemical Handbook.
Basics II ”edited by The Chemical Society of Japan, 3rd edition revised in 1984, Maruzen shares
It is described on pages II-339 to II-342 issued by the company.
Among them, all compounds having the pKa defined in the present invention
Can be used. Of these, especially aspartic acid and alani
Amino acids such as amino acids, glycine and glutamic acid and their
Salts are preferred. These compounds can be used as a mixture of two or more
May be added, or different compounds may be used for the first and second additions.
May be. In addition, these compounds are suitable acids or bases
A mixture (salt) with an acidic compound may be used,
When preparing an aqueous solution (water dispersion) to promote dissolution,
Thus, an appropriate acid or basic compound may be used in combination. In particular
When the compound-containing solution is added later, its pH is adjusted to 6.0 to 9.
5, more preferably adjusted to 7.0-8.0 and added
desirable. The amount of the compound added to the washing solution is 0.040 to 10% by weight,
More preferably, 0.10 to 5.0% by weight is suitable. When circulating and reusing the washing liquid for washing,
Not only does it mix with bacteria in the air and reduce the washing effect
Since it emits unpleasant odor, it is not preferable,
It is desirable to include an agent and / or a bactericide. Automatic elution for plate making of the electrophotographic lithographic printing plate of the present invention
Machine, and further has at least an elution section and a water washing section.
In addition, those with a structure having a plate surface protective agent application part are preferred.
However, the lithographic printing plate is automatically transported and
It is only necessary to be able to perform the cleaning (washing) process.
It is not limited to. However, due to the deterioration of the eluate over time,
In consideration of this, the supply of eluate to the photoconductive layer surface depends on the method.
In this case, a large amount of the solubilized photoconductive layer
Since it may flow into the effluent and promote deterioration,
It is desirable that the liquid is supplied as softly as possible. Dissolution
The way to supply the outlet part softly is to use an eluate supply pipe.
The liquid discharged from the plate is transferred to another member, for example, a current plate,
It is preferable to supply the photoconductive layer uniformly through the
is there. The discharge amount of the eluate at that time is supplied uniformly to the printing plate
The minimum amount possible is sufficient, but when transported to the washing section, the printing plate
1.5 to 100 times, more preferably 5.0 to 50 times the amount of liquid taken out
Is good. Also, it is better to take out the eluate as little as possible
Good, 10g / m^TwoIt is desirable to adjust mechanically so that
New In the rinsing section, the rinsing liquid is supplied onto the plate and solubilized quickly.
For completely removing the removed photoconductive layer and excess eluate
Must. If the liquid is a mechanism that can control scattering
For example, it may be directly supplied to the solubilized photoconductive layer.
Application of the dissolution promoting member described in JP 60-76395A to a water washing mechanism
You may. In the washing section, use a rotating brush.
The photoconductive layer solubilized by direct contact with the photoconductive layer is scraped off.
However, the solubilized photoconductive layer is usually mechanically scratched.
Easy removal without dropping and side etch
It is not recommended to use it because it may accelerate deterioration.
I don't. The washed electrophotographic lithographic printing plate can be acidified if necessary.
Treatment with a rinsing solution containing an acidic substance. The rinsing liquid that can be used in the present invention is plate-processed.
Binder resin in the electrophotographic lithographic printing plate photoconductive layer is re-aggregated
It is desirable that the pH of the solution is adjusted so as not to cause the problem. That is,
The initial pH of the sensing solution must at least promote the insolubilization of the binder resin.
If the pH is at least neutral during liquid circulation
Binder resin that flows in with the rinsing liquid maintains the solubilized state
Therefore, the above trouble due to re-insolubilization of the binder resin is prevented.
I can stop it. However, the rinse solution may be slightly
Into the protective gum solution for plate surface protection that is usually performed after
Therefore, if the pH of the rinse solution is high, the pH of the protective gum
Inevitably, it rises early and the plate surface protection effect decreases,
It is desirable to maintain the pH of the rinsing liquid at 7 or less. This rinse solution contains various test materials to adjust the pH of the solution.
Can be added. In particular, a large number of
To process electrophotographic lithographic printing plates more stably,
Fluid pH fluctuates during multiple plate making, at least for rinse solution
It is desirable not to use acid and water as buffer
It is desirable to contain at least one of
No. As a result, the rinsing liquid according to the present invention is electrophotographically flattened.
When applied to a printing plate, it may occur due to eluate remaining on the plate.
The neutral component is neutralized, and the non-image area becomes more hydrophilic.
Become. The electrophotographic lithographic printing plate from which the non-image part photoconductive layer has been removed,
The purpose of improving the scratch resistance of the plate surface and desensitizing the non-image area
Protective gum treatment. The protective gum solution that can be used in the present invention includes a polymer
Compounds, lipophilic substances, surfactants, etc.
All known reagents can be used.

【Example】

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless departing from the gist of the invention. Example 1 * conductive support Preparation of JIS1050 aluminum sheet 60 ° C., and immersed in 10% NaOH aqueous solution, the amount of dissolved aluminum was etched so as to become 6 g / m ^2. After washing with water, it was immersed in a 30% nitric acid aqueous solution for 1 minute to neutralize, and sufficiently washed with water. Thereafter, electrolytic surface roughening was performed in a 2.0% aqueous nitric acid solution for 25 seconds, and the surface was washed by immersion in a 20% aqueous sulfuric acid solution at 50 ° C., followed by washing with water. In addition, 20%
An anodizing treatment was carried out in a sulfuric acid aqueous solution, followed by washing with water and drying to prepare a printing plate support. At this time, the center line average roughness (Ra ₁ ) of the surface treated surface of the support was 0.52 μm. * Preparation and application of coating liquid for photoconductive layer
The following photoconductive layer composition dispersed in time was applied by a bar coater and dried at 90 ° C. for 5 minutes to prepare an electrophotographic lithographic printing plate. At this time, the coating amount of the photoconductive layer was 4.5 g / m ² , and the center line average roughness (Ra ₂ ) of the surface was 0.22 μm (that is, 1/6 <Ra ₂ / Ra ₁ < 1/2). Photoconductive layer coating liquid 1 composition Butyl methacrylate / methacrylic acid copolymer (methacrylic acid 40 mol%) 18 parts by weight χ type metal-free phthalocyanine 4 parts by weight 1,4-dioxane 60 parts by weight 2-propanol 18 parts by weight * toner development The obtained printing plate precursor is charged in a dark place by corona discharge so that the surface potential (V ₀ ) becomes about +300 V, and then is subjected to scanning image exposure using a semiconductor laser (780 nm). When liquid reversal development was performed with a toner (LOM-ED III, manufactured by Mitsubishi Paper Mills, Ltd.) and the toner was thermally fixed, a toner image having a resolution of 50 lines / mm was obtained with good reproducibility on the photoconductive layer. The sharpness of the image was also good. * Plate making process Next, an automatic elution machine, eluate, washing solution,
And a plate-making process using a rinsing liquid. 1) Automatic dissolution machine A dispensing device that has a dissolution tank, a subsequent washing tank, and a rinsing tank, and that transports the electrophotographic lithographic printing plate after toner development, and a storage tank, a pump, and a spray nozzle for processing liquid in each processing tank. → An automatic machine having a device for circulating in the storage tank cycle and a replenishing device for each processing tank was used. 2) Eluent 1 composition Sodium silicate aqueous solution (SiO ₂ content 30% by weight, SiO ₂ / Na ₂ O
Molar ratio 2.5) 20 parts by weight Potassium hydroxide 1 part by weight Pure water 79 parts by weight 3) Rinse solution 1 composition (20 dm ³ ) Na dioctyl sulfosuccinate 0.1 part by weight 2-methyl-3-isothiazolone 0.01 part by weight in pure water A solution prepared by dispersing and dissolving to 100 parts by weight was charged into a washing tank, and after the plate making for 100 plates, 15 ml of a 5% by weight glycine aqueous solution was added every time the printing plate (A2 size) was treated for 10 plates. 4) Rinse liquid 1 composition (20 dm ³ ) 0.5 parts by weight of succinic acid 0.5 parts by weight of phosphoric acid (85% aqueous solution) 0.05 parts by weight of decaglyceryl monolaurate 0.01 parts by weight of 2-methyl-3-isothiazolone 0.01 parts by weight of sodium hydroxide The solution was adjusted to pH 4.7, and then adjusted to 100 parts by weight with pure water. When plate making was performed using the above-mentioned processing solution (elution time was set to 8 seconds), the side etch was only about 3 μm on one side and the fluctuation was slight. No failure such as pigment remaining) was observed. Next, printing was performed using this printing plate with an offset printing machine (Hamaduster 600 CD). As a result, at least 100,000 sheets of printed matter were free of stains and good printed matter was obtained. Example 2 During the surface treatment step of the conductive support prepared in Example 1,
A new support was produced by changing the electrolytic surface roughening time.
The photoconductive layer coating solution 1 was applied thereto to obtain an electrophotographic lithographic printing plate having the surface shape shown in Table 1. Table 1 Center line average roughness (μm) Support surface Photoconductive layer surface Ra ₂ (Ra ₁ ) (Ra ₂ ) Ra ₁ 0.38 0.18 0.47 0.45 0.22 0.49 0.60 0.26 0.43 0.66 0.27 0.41 0.73 0.30 0.41 Electrophotographic lithography All the printing plates were developed under the same conditions as in Example 1 and subjected to plate making.
In all the printing plates in the table, a toner image having a resolution of 50 lines / mm was obtained with good reproducibility, and the sharpness of the image was also good. Also,
The dissolution property and printing durability (100,000 sheets) were the same, and there were no problems. Comparative Examples 1 to 3 In the same manner as in Example 2, the support having the surface shape shown in Table 2 was obtained by changing the electrolytic surface roughening time during the preparation of the conductive support. Table 2 center line average roughness ([mu] m) Comparative Example support surface photoconductive layer surface _{Ra 2 (Ra 1) (Ra} 2) in _{Ra 1 1 0.26 0.16 0.61 2 1.1} 0.33 0.30 3 1.5 0.35 0.23 or more each support Photoconductive layer coating liquid 1 was applied and dried under the same conditions as in Example 1. When all the obtained electrophotographic lithographic printing plates were developed and subjected to plate making under the same conditions as in Example 1, the printing plate of Comparative Example 1 provided a toner image having a resolution of 50 lines / mm with good reproducibility. The sharpness was also good, but the printing durability was poor and the photoconductive layer peeled off during printing. On the other hand, in Comparative Examples 2 and 3, the center line average roughness of the surface of the photoconductive layer was also increased, so that the resolution of the toner image was deteriorated. In the elution, the photoconductive layer remained in the valley surface of the support without being eluted. On the other hand, the side etch greatly fluctuated, and toner thin line jump occurred in part. Example 3 The following photoconductive layer composition (coating liquids 2 to 5) was applied to the surface-treated surface of the printing plate support prepared in Example 1 under the same conditions as in Example 1 to prepare an electrophotographic lithographic printing plate. Was prepared. Composition of coating liquid for photoconductive layer 2 Vinyl acetate / crotonic acid copolymer (3 mol% of crotonic acid) 18 parts by weight χ type metal-free phthalocyanine 4 parts by weight 1,4-dioxane 60 parts by weight 2-propanol 18 parts by weight Photoconductive layer Coating liquid 3 composition Styrene / butyl acrylate / acrylic acid copolymer
(Molar ratio 50:15:35) 18 parts by weight χ-type metal-free phthalocyanine 4 parts by weight Xylene 60 parts by weight 2-propanol 18 parts by weight Photoconductive layer coating liquid 4 composition Styrene / monooctyl maleate copolymer
(Molar ratio 60:40) 18 parts by weight χ-type metal-free phthalocyanine 4 parts by weight Xylene 40 parts by weight oxolane 20 parts by weight 2-propanol 18 parts by weight Photoconductive layer coating liquid 5 composition Benzyl methacrylate / methacrylic acid copolymer (molar ratio 70:30) 18 parts by weight χ-type metal-free phthalocyanine 4 parts by weight Methyl cellosolve acetate 60 parts by weight 2-propanol 18 parts by weight Each of the obtained electrophotographic lithographic printing plates was subjected to toner development in the same manner as in Example 1. It had the same resolution and image quality as the printing plate developer of Example 1. Next, a plate making process was performed using an eluate, a washing solution, and a rinse solution as described below. Eluent 2 composition Monoethanolamine 0.5 parts by weight Triethanolamine 6 parts by weight Benzyl alcohol 1.5 parts by weight EDTA-4H 0.4 parts by weight Potassium hydroxide 2 parts by weight Pure water 89.6 parts by weight Washing liquid 2 composition (20 dm ³ ) Polyoxyethylene ( 6) 0.15 parts by weight of monooleate Dissolve and dissolve 0.20 parts by weight of hot ethanol solution of 5% by weight of dehydroacetic acid in pure water to make up to 100 parts by weight. Put the solution in a washing tank, and after printing 100 plates, make 10 plates (A2 size). For each treatment, 10 ml of a 4% by weight aqueous solution of ammonium bicarbonate was added. Rinse liquid 2 composition (20 dm ³ ) Citric acid 0.2 parts by weight Adipic acid 0.2 parts by weight Phosphoric acid (85% aqueous solution) 0.4 parts by weight Sorbitan monolaurate 0.05 parts by weight Sodium hydroxide was added thereto to adjust the solution pH to 5.0. Then, it was adjusted to 100 parts by weight with pure water. Plate making was performed using the above processing solution (elution time was set so that the side etch was eluted to about 3 μm on one side)
No elution failure such as elution delay in the non-image area (pigment remaining) was observed in all the printing plates. Next, when this printing plate was used for printing on an offset printing machine (Hamaduster 600 CD), all printed plates were printed, and at least 100,000 sheets were printed without any stains on printed matter. A printed matter was obtained. Example 4 A JIS1050 aluminum sheet was immersed in a 10% NaOH aqueous solution at 60 ° C., and was etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was immersed in a 30% nitric acid aqueous solution for 1 minute to neutralize, and sufficiently washed with water. Thereafter, electrolytic surface roughening was performed in a 3.0% hydrochloric acid aqueous solution at 35 A / dm ^{2 for} 50 seconds, the surface was immersed in a 20% sulfuric acid aqueous solution at 50 ° C. to wash the surface, and then washed with water. Furthermore, anodizing treatment is performed in a 20% sulfuric acid aqueous solution,
By drying, a support for a printing plate was prepared. At this time, the center line average roughness (Ra ₁ ) of the surface treated surface of the support was 0.55
μm. The surface of the support is treated with a paint shaker.
The following photoconductive layer composition dispersed in time was applied by a bar coater and dried at 90 ° C. for 5 minutes to prepare an electrophotographic lithographic printing plate. At this time, the coating amount of the photoconductive layer was 4.5 g / m ² , and the center line average roughness (Ra ₂ ) of the surface was 0.21 μm (that is, Ra ₂ / Ra ₁ = 0.38). Composition of coating liquid for photoconductive layer 6 Butyl methacrylate / methacrylic acid copolymer (40 mol% of methacrylic acid) 18 parts by weight χ-type metal-free phthalocyanine 4 parts by weight Methyl cellosolve acetate 60 parts by weight 2-propanol 12 parts by weight 2-furanmethanal 6 parts by weight The obtained printing plate precursor was subjected to corona discharge in a dark place to be charged so as to have a surface potential (V ₀ ) of about +300 V, and then subjected to scanning image exposure using a semiconductor laser (780 nm). Immediately after performing liquid reversal development with a positively charged toner (manufactured by Mitsubishi Paper Mills, LOM-ED III) and thermally fixing the toner, a toner image with a resolution of 50 lines / mm was obtained with good reproducibility on the photoconductive layer. . The sharpness of the image was also good. Next, a plate making process was performed using an eluate, a washing solution, and a rinse solution as described below. Eluent 3 composition Potassium silicate aqueous solution (SiO ₂ content 20% by weight, SiO ₂ / K ₂ O molar ratio 3.5) 30 parts by weight Sodium hydroxide 1 part by weight Pure water 69 parts by weight Washing liquid 3 composition (20 dm ³ ) dioctyl sulfo amber 0.1 part by weight of sodium acid 0.1 part by weight of p-butyl benzoate dispersed and dissolved in pure water to make up to 100 parts by weight is charged into a washing tank, and after 100 plates are made, the printing plate (A2 size) is treated every 10 plates. Was added with 15 ml of a 5% by weight aqueous glycine solution. Rinse liquid 3 composition (20 dm ³ ) Succinic acid 0.2 parts by weight Citric acid 0.3 parts by weight Sorbitan monolaurate 0.05 parts by weight 2-Methyl-3-isothiazolone 0.01 parts by weight Sodium hydroxide was added thereto to adjust the pH of the solution to 4.7. Then, it was adjusted to 100 parts by weight with pure water. When plate making was performed using the above-mentioned processing solution (elution time was set to 8 seconds), the side etch was only about 3 μm on one side and the fluctuation was slight. No failure such as pigment remaining) was observed. Next, printing was performed using this printing plate with an offset printing machine (Hamaduster 600 CD). As a result, at least 100,000 sheets of printed matter were free of stains and good printed matter was obtained. Comparative Example 4 Using the conductive support prepared in Example 4, a photoconductive layer coating liquid 7 having the following composition was applied and dried under the same conditions as in Example 4. The center line average roughness (Ra ₂ ) of the obtained photoconductive layer surface is 0.34μ.
m (that is, Ra ₂ / Ra ₁ = 0.62> 1/2). Photoconductive layer coating liquid 7 composition Butyl methacrylate / methacrylic acid copolymer (methacrylic acid 40 mol%) 18 parts by weight χ type metal-free phthalocyanine 4 parts by weight 1-propyl acetate 66 parts by weight 2-propanol 12 parts by weight When all the lithographic printing plates were developed and subjected to plate making under the same conditions as in Example 1, the resolution of the toner image deteriorated, and the elution caused the photoconductive layer to remain in the valley on the surface of the support without being eluted. On the other hand, the side etch greatly fluctuated, and toner thin line jump occurred in part. Comparative Example 5 A JIS1050 aluminum sheet was immersed in a 10% NaOH aqueous solution at 60 ° C., and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was immersed in a 30% nitric acid aqueous solution for 1 minute to neutralize, and sufficiently washed with water. Thereafter, electrolytic surface roughening was performed in a 3.0% hydrochloric acid aqueous solution at 25 A / dm ^{2 for} 20 seconds, and the surface was immersed in a 20% aqueous sulfuric acid solution at 50 ° C. to wash the surface, and then washed with water. Furthermore, anodizing treatment is performed in a 20% sulfuric acid aqueous solution,
By drying, a support for a printing plate was prepared. At this time, the center line average roughness (Ra ₁ ) of the surface treated surface of the support was 0.28
μm. The photoconductive layer coating solution 6 was applied to the support under the same conditions as in Example 4 and dried. When all the obtained electrophotographic lithographic printing plates were developed and subjected to plate making under the same conditions as in Example 4, a toner image having a resolution of 50 lines / mm was obtained on the photoconductive layer with good reproducibility, and the sharpness of the image was improved. However, the printing durability was poor and the printing background was stained and the photoconductive layer was peeled off during printing. Example 5 The following photoconductive layer composition was prepared and coated on the surface-treated surface of the printing plate support prepared in Example 4 under the same conditions as in Example 4 to prepare an electrophotographic lithographic printing plate. Photoconductive layer coating liquid 8 composition Benzyl methacrylate / methacrylic acid copolymer (molar ratio 70:30) 18 parts by weight Oxolan 60 parts by weight Hydrazone compound shown on next page 3.2 parts by weight 1.36 parts by weight of the following trisazo compound At this time, the center line average roughness (Ra ₂ ) of the photoconductive layer surface was 0.2
It was 5 μm (that is, Ra ₂ / Ra ₁ = 0.45). The obtained printing plate precursor was charged in a dark place by corona discharge so as to have a surface potential (V ₀ ) of about +450 V, and then charged with He-
A scanning image was exposed using a Ne laser (633 nm), and liquid reversal development was immediately performed with a positively charged toner (Ricoh MRP, manufactured by Ricoh Co., Ltd.). The toner was thermally fixed. The resolution was 50 lines / mm on the photoconductive layer. Was obtained with good reproducibility. The sharpness of the image was also good. Next, a plate making process was performed using an eluate, a washing solution, and a rinse solution as described below. Eluent 4 composition Potassium silicate 4 parts by weight Ethanol 10 parts by weight Potassium hydroxide 1 part by weight Pure water 85 parts by weight Washing liquid 4 composition (20 dm ³ ) Na dioctylsulfosuccinate 0.15 parts by weight Benzisothiazolone 0.01 parts by weight Disperse in pure water After dissolving the solution to 100 parts by weight, the solution was charged into a washing tank, and 20 ml of a 5% by weight β-alanine aqueous solution was added every time the plate was processed for 10 plates (A2 size) after plate making for 100 plates. Rinse solution 4 composition (20 dm ³ ) Citric acid 0.8 parts by weight Ammonium dihydrogen phosphate 0.5 parts by weight Sorbitan monolaurate 0.05 parts by weight After adding potassium hydroxide to adjust the solution pH to 5.0,
100 parts by weight with pure water. When plate making was performed using the above processing solution, no failure such as elution delay (pigment remaining) in the non-image area was observed. Next, printing was performed using this printing plate with an offset printing machine (Hamaduster 600 CD). As a result, at least 100,000 sheets of printed matter were free of stains and good printed matter was obtained.

【The invention's effect】

By using the electrophotographic lithographic printing plate of the present invention, a printing plate having good image resolution and the like was obtained, and a high-quality printed image was obtained without occurrence of background smear or plate skipping.

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁷ Identification code FI G03G 5/10 G03G 5/10 B 5/14 101 5/14 101B (56) References JP-A-63-226668 (JP, A JP-A-57-147656 (JP, A) JP-A-61-49895 (JP, A) JP-A-1-269944 (JP, A) JP-A-1-261660 (JP, A) 20048 (JP, A) JP-A-53-141701 (JP, A) JP-A-4-22972 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/28 G03G 5 / 10 G03G 5/04 G03G 5/14 101

Claims (7)

(57) [Claims] 1. A lithographic printing plate having a photoconductive layer comprising at least an organic photoconductive compound and a binder resin provided on a conductive support. And then contacting with an alkaline eluent to elute and remove the non-image area photoconductive layer other than the toner image area to form a lithographic printing plate. Center line average roughness of layer side surface (Ra ₁ )
Is 0.3 to 0.8 μm, and the ratio [Ra ₂ / Ra ₁ ] to the center line average roughness (Ra ₂ ) of the photoconductive layer surface is 1/6 to 1/2. Electrophotographic lithographic printing plate. 2. The photoconductive layer side surface of the electroconductive support comprises at least an aluminum oxide layer and has a rough surface having a bearing length (Rtp) of 70 to 85% as defined in ISO 4287/1. Electrophotographic lithographic printing plate. 3. The electrophotographic lithographic printing plate according to claim 1, wherein the monomer constituting the binder resin is at least one selected from acrylic acid, methacrylic acid, crotonic acid and maleic acid monoester. 4. The electrophotographic lithographic printing plate according to claim 3, further comprising at least one of a carboxylic acid ester having a vinyl group in the molecule and styrene as a monomer constituting the binder resin. 5. The organic photoconductive compound is a phthalocyanine pigment, and the weight ratio (P / B) of the binder resin (B) and the phthalocyanine pigment (P) contained in the photoconductive layer is from 1/6. 1/3
The electrophotographic lithographic printing plate according to claim 1, wherein 6. A phthalocyanine pigment having an average particle size of 0.2 μm
6. A χ-type metal-free phthalocyanine pigment comprising:
Electrophotographic lithographic printing plate as described. 7. A photoconductive layer comprising at least two atoms of nitrogen and oxygen atoms in the molecule, dissolving 5% by weight or more of water and a solvent having a specific gravity (25 ° C.) of 0.95 or more. 6. The electrophotographic lithographic printing plate according to claim 5, wherein the lithographic printing plate is formed by applying a coating liquid containing at least% by weight.