JPH056018A - Original plate for electrophotographic planographic printing - Google Patents

Abstract

PURPOSE:To prevent the generation of staining particularly by rubbing and to improve printing performance (lessen the generation of waving of rules) by improving the constitution and compsn. of a back layer. CONSTITUTION:The back layer of the original plate for electrophotographic planographic printing constituted by providing at least a photoconductive layer on one surface of a base and the back layer on the other surface consists of the outermost layer contg. a hydrophilic high polymer and an inside layer having 0.03g/m<2>.min dehumidification speed ]excluding the case where the water- absorbing capacity by a Cup method is 25g/m<4> (45 minute value)]. Since the water resistance and the property to prevent the staining by rubbing can be made compatible, there are no deformation of the original plate, etc., and the waving of the printed rules is not generated in spite of a change in the environment for plate making. Printing of a large number of sheets with good image quality is thus possible. This original plate is effective as well even when applied to the printing original plate for electrophotographic plate making which executes not only ordinary development but also development by a direct, power feed system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic lithographic printing plate precursor, and more particularly to an electrophotographic lithographic printing plate precursor having excellent printability, capable of obtaining a printed matter of high image quality and having good printing workability. is there.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a lithographic printing plate precursor by an electrophotographic method, a photoconductive layer of an electrophotographic lithographic printing plate precursor is uniformly charged and imagewise exposed, and then wet-developed with a liquid toner. A method of obtaining a toner image, fixing the toner image and then treating with a desensitizing liquid (etching liquid) to make the non-image portion having no toner image hydrophilic is generally adopted. Paper or the like having conductivity has been conventionally used as a support for the lithographic printing plate precursor, but the permeation of water into the support affects printing power and photographic performance. That is, the above-mentioned etching solution or immersion water during printing permeates to extend the support, and sometimes peeling occurs between the support and the photoconductive layer to reduce printing durability. The water content of the support changes depending on the temperature and humidity conditions, and as a result, the conductivity of the support changes, which adversely affects the photographic performance. Moreover, wrinkles will occur during printing if there is no water resistance. In order to solve such a problem, a water-resistant epoxy resin or a copolymer of ethylene and acrylic acid or the like is applied to one or both sides of the support (Japanese Patent Laid-Open Nos. 50-138904 and 55-55). 105
580, 59-68753, etc.) or a laminated layer of polyethylene or the like (Japanese Patent Laid-Open No. 58-5).
7994). A layer provided as a backing layer on the surface of the support opposite to the surface having the photoconductive layer (printing surface, top) is called a back layer. This back layer-forming composition provides the above-mentioned water resistance. Not only is it being repeatedly improved for the purpose of maintaining various functionalities.

By the way, the inventors of the present invention changed the conventional developing method of the electrophotographic printing plate precursor to the method of passing the developing solution between the electrodes and passing the master, and the side opposite to the printing surface. We have developed a wet development method by a so-called direct power supply method, in which a conductor is used instead of the electrode, and development is performed while electrons are directly supplied from the conductor to the back side of the support, and it has already been developed.
It is proposed in JP-A-3-89373. As a method for improving this, the surface electric resistance of the back layer of the support having a polyolefin laminate layer on both sides of the support is 1 × 10 5.
By providing a layer with a friction resistance of ¹⁰ Ω or less and a greater friction resistance than the polyolefin laminate layer, the winding and fixing on the drum of the printing machine will be accurate, printing misalignment will be prevented and good electrophotographic plate making will be possible. An original plate that can also be used has been proposed (Japanese Patent Laid-Open No. 2-84665).
Further, an under layer and a photoconductive layer are provided on the surface of the support, and a back layer is provided on the back surface, and the surface resistivity of the under layer is 1 × 10 ⁸
-1 × 10 ¹⁴ , and by setting the back layer to 1 × 10 ¹⁰ or less, accurate, good and quick, no pinholes are generated on a solid screen by any wet development of conventional method and direct power feeding method. An original plate capable of forming a uniform image and a developing method thereof have been proposed (JP-A-2-132464).

[0004]

By the way, since the lithographic printing plate precursor is usually wound in a roll shape, the back layer and the printing surface (top layer) come into contact with each other, so that a composition for forming a back layer, such as water resistance, is used. The substance or the like for application is transferred to the top layer. If this water resistance improver adheres to a portion without a toner image (non-image area), when the non-image area is subjected to hydrophilic treatment, the adhered portion does not have sufficient hydrophilic treatment, which causes stains (cosmetics) on the printed matter. There is a problem in that it is called "dirt". If the amount of waterproofing agent added to the back layer is reduced in an attempt to prevent this, the waterproofness will naturally decrease, and for example, the moisture in the atmosphere will be absorbed while nipping in the plate making machine, and the support will stretch and become wavy. However, when printing with such a master, the problem arises that the straight line portion is wavy. That is, it is difficult to prevent both the scorching stain and the waterproofness (preventing the deformation of the support due to changes in the environment). Further, the back layer is required to have a function of easily adhering to the plate cylinder (fitting property), and also a function of guaranteeing printing workability such as displacement from the plate cylinder, and printability. Satisfaction is required. Therefore, the object of the present invention is to have good characteristics against scorching stains, and to prevent problems such as the original plate stretching and wavy due to environmental changes in the plate making machine, and the fact that ruled lines are bent and printed as a real damage. An object of the present invention is to provide an electrophotographic lithographic printing plate precursor that simultaneously solves printing performance such as possible. Further, another object of the present invention is for electrophotographic lithographic printing which can be applied to development of ordinary electrophotographic plate making as well as development of a direct power feeding method, and which can satisfy both the above-described smear stain and printing performance. To provide the original version.

[0005]

As a means for solving the above-mentioned problems, the present invention provides an electrophotographic lithographic printing plate precursor comprising a support having at least a photoconductive layer on one surface and a back layer on the other surface. , The back layer is an outermost layer containing a hydrophilic polymer and an inner layer having a dehumidifying speed of 0.03 g / m ² · min or less (however, the water absorption by the Cobb method is 25 g /
m ² (value at 45 minutes) or less] is included].

[0006]

According to the present invention, the back layer is composed of a plurality of layers, and the outermost layer and the inner layer have different functions, thereby achieving both waterproofness and hydrophilicity, which have been difficult to achieve in the past. That is, the back layer of the present invention is an outermost layer containing a hydrophilic polymer (hereinafter referred to as A layer).
And an inner layer having a dehumidifying speed of 0.03 g / m ² · min or less (hereinafter referred to as B layer).

The dehumidifying speed in the present invention will be described below. The dehumidification speed is an index relating to the ease with which the water contained in the layer escapes and the permeability of H ₂ O to the support. Specifically, the electrophotographic lithographic printing plate precursor adjusted to have a water content of 5.5% is made to face the photosensitive layer side, and the cellophane tape is firmly attached to the four sides to prevent water from entering and exiting from the sides. This 3
The sample is left in an atmosphere of 0 ° C. and 20% RH for 60 minutes, the weight before and after dehydration is measured, and a value converted per 1 m ² per minute is defined as a dehumidification speed. Usually, the original size for measurement is 280 mm × 400 mm. The measuring method and calculating method of the above "water content" are as follows. Let a ₁ be the weight measurement value of the electrophotographic lithographic printing plate precursor. Place this in an oven at 140 ° C for 15 minutes to dry, then at 20 ° C.
The sample is taken out in an atmosphere of / 65% RH and the weight after 5 seconds is measured. This measured value is a ₂ . The value (%) calculated from this value by the following formula is defined as the moisture value. Moisture value (%) = [(a ₁ −a ₂ ) / a ₁ ] × 100 Note that the original size for measurement is usually 280 mm × 4.
Perform at 00 mm.

Further, the layer B of the present invention is one having the above dehumidification speed of 0.03 g / m ² · min or less but excluding the water absorption by the Cobb method of 25 g / m ² (45 minutes value). .. Here, the Cobb method is JIS P-8140 "Paper and board water absorption test method (Cobb method)", and the water absorbency when one side of non-absorbent paper and board is in contact with water for a certain period of time. In the present invention, the contact time is 45 minutes. Further, the water absorption by this method is not directly related to the water repellency of paper.

In the present invention, since the outermost layer A contains a hydrophilic polymer, a large amount of the hydrophilic polymer is transferred to the top even when the back layer surface comes into contact with the top layer in a roll state. Since it is a layer that does not interfere with the hydrophilic treatment, it is possible to prevent the occurrence of scorching stains.
Hydrophilic colloid particles and the like may be added to the layer A for the purpose of further increasing the anti-corrosion ability. The back layer B of the present invention has an inner layer having a low dehumidification speed of 0.03 g / m ² · min or less (however, the water absorption by the Cobb method is 25 g / m ²
m ² (value of 45 minutes or less) is provided, the humidity of the support is not easily affected by environmental changes, sufficient water resistance and waterproofness can be secured, and during the plate making process, It is possible to prevent the support body from being deformed and the straight lines such as ruled lines from being wavy. Further, the layer A has the main purpose of preventing the occurrence of scorching stains, but the layer B can maintain the performance required as a printing plate. The B layer may have a single-layer structure, but may have a plurality of layers. A hydrophilic polymer binder such as an organotitanium compound may be added to one or both layers for the purpose of improving the adhesion of the A layer to the B layer. As described above, according to the present invention, it is possible to achieve both the contradictory functions of preventing smearing and waterproofing.

The back layer of the present invention will be described in more detail below. The layer A of the present invention is a layer containing a hydrophilic polymer. In FIG. 1, a layer B according to the present invention is formed on a support, and the composition of the formulation (A-2) of Example 2 described later as the layer A (containing no hydrophilic polymer), (A-2). Of the composition in which 2,5,10% of the acrylic weight composition ratio of 53% was replaced with polyvinyl alcohol (abbreviated as PVA) which is a hydrophilic polymer in each of the above formulas. With respect to the sample, a photoconductive layer is further formed with a common composition, the obtained electrophotographic printing plate precursor is printed, and the result of examination of the occurrence of smear stain is shown. In FIG. 1, ◯ means no occurrence, Δ means slight occurrence, and x means occurrence. As is clear from FIG. 1, as the PVA substitution amount (S) increases, the occurrence of scorching stains decreases. It can also be seen that the A layer is effective even if it is considerably thin, and that if it exceeds 1 μm, the effect is hardly changed even if the thickness is further increased.

As the hydrophilic polymer for the layer A of the present invention, any known natural or synthetic hydrophilic polymer may be used. Specifically, for example, in addition to ordinary lime-processed gelatin, acid-processed gelatin, modified gelatin, gelatin such as derivative gelatin, albumin, sodium alginate, gum arabic, latex, cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and other celluloses. One or more of water-soluble derivatives such as starch and starch, hydrophilic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, and styrene-maleic anhydride copolymer can be used. The addition of hydrophilic colloid particles further improves the anti-corrosion ability.

The A layer of the present invention comprises the above hydrophilic polymer and other A
And a layer forming material. As the material for forming the A layer, for example, one or more kinds of various water resistant materials, water resistant organic solvent resistant materials, synthetic emulsions and the like can be used. The water-resistant material is a water-resistant film-forming material such as polyvinyl chloride, acrylic resin, polystyrene, polyethylene, alkyd resin, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, or organic solvent resistant film. Examples of the forming material include starch, oxidized starch, PVA, methyl cellulose, hydroxyethyl cellulose, CMC and the like. As the water resistant organic solvent resistant material, for example, ethylene-vinyl alcohol copolymer, high polymerization polyester, high polymerization polyurethane, etc. are used. In addition, starch, PVA, acrylic resin (reactive acrylic resin, organic solvent solution type or O / W type emulsion type), alkyd resin (air curing type), etc., and crosslinking agent such as melamine resin It is also possible to use in combination with and as a water resistant organic solvent resistant material. As the synthetic emulsion, monomers or prepolymers such as acrylic acid ester, methacrylic acid ester, vinyl chloride, vinylidene chloride, vinyl acetate, polyurethane, prepolymer, acrylonitrile, butadiene, styrene-butadiene are emulsion-polymerized or emulsion-copolymerized. The thing obtained by superposing | polymerizing can be mentioned. These A layer forming materials can be used together. In addition, a dispersant, a leveling agent, a cross-linking agent and the like can be added to the layer A, if necessary. The proportion of the hydrophilic polymer present in the total amount of the composition for forming layer A is preferably in the range of 3 to 40% by weight.

The layer B of the present invention has a dehumidifying speed of 0.03 g.
/ M²・ Cobb among those satisfying the condition of min or less
Water absorption by the method is 25g / m²(45 minutes value) or less
Except for. This dehumidification speed value is B
It depends not only on the composition of the layer but also on the thickness of the B layer. Same composition
If so, the dehumidification speed decreases as the layer thickness increases.
In Fig. 2, the B layer formed on the support to a thickness of 7 µm (dry thickness) was removed.
Wet speed and degree of deformation when printing straight lines (ruled lines)
The result of examining the relationship is shown. Each layer B has the formulation described below.
In (B-1), SBR is replaced with acrylic,
Change the dehumidification speed by adjusting the clay / binder ratio
And each layer B has a water absorption of 85 g / cm. ²A layer of
It was provided with a general composition. A photoconductive layer is formed on this support to
Sub-printing plate for printing plate, 25 ℃, 30% R
Mark the deformation when left in the nip for 15 hours under H environment.
It was judged by the wavy state of the ruled line (straight line) when printing. Ruled line
Print and draw a tangent to the rippling valley and from this tangent the wave peak
If the distance to 0 to 0.2 mm or less
Since it is not possible, it was judged as a pass (○). Also, 0.2 mm
If the bend is visible even when visually checked, it is judged as rejected (x)
did. Even if it exceeds 0.2 mm and you can see a slight bend
Was marked with △. As can be seen from Fig. 2, dehumidification speed
0.03g / m²・ Under min, the ripple evaluation is ○
I understand.

As the material for forming the B layer, various water resistant materials, water resistant organic solvent resistant materials and synthetic emulsions described above as the material for forming the A layer can be used, and further a water-soluble polymer compound can also be used. .. Examples of the water-soluble polymer compound include starch or a water-soluble derivative thereof, a water-soluble cellulose derivative, casein, polyvinyl alcohol, a styrene maleic anhydride copolymer, and a vinyl acetate-maleic anhydride copolymer. .. Also in this case, the amount used is selected so that the water absorption of the layer B is 25 g / m ² or less. These B layer forming materials can be used in combination, and a dispersant, a leveling agent, a cross-linking agent and the like can be added if necessary, as in the case of the A layer. Further, as described above, the adhesion of both layers can be improved by adding a hydrophilic polymer binder such as an organic titanium compound to one or both of the A layer and the B layer.

In the present invention, the thickness of the layer A is not particularly limited as long as it can exhibit its performance, but is about 0.5 to 10 μm. Moreover, the thickness of the B layer is about 2 to 25 μm. When the layer B has a multilayer structure, the total thickness may be within this range. The total thickness of the entire back layer including the layers A and B of the present invention is generally 3 to 25 μm, preferably 8 to 15 μm.

As the support of the present invention, any of the known supports used for this type of electrophotographic lithographic printing plate precursor can be used. For example, a substrate such as metal, paper, or a plastic sheet, or a substrate which is electrically conductive by impregnating a low resistance substance, or a substrate having a water-resistant adhesive layer or at least one precoat layer on the surface thereof. It is possible to use, for example, a substrate obtained by laminating a base conductive plastic having vapor deposited Al, Al or the like on paper. Specific examples of the conductive substrate or the conductive material include Yukio Sakamoto, "Electrophotography" 14, (No.1), p2-11 (1975), Hiroyuki Moriga, "Introduction to Special Paper Chemistry," Polymer Society (1975),
MF Hoover, J. Macromol. Sci. Chem., A-4
(6), p1327 to 1417 (1970) and the like are used.

The photoconductive layer of the present invention contains at least a photoconductor and a binder, and the photoconductor may be either an inorganic material or an organic material. Examples of the inorganic photoconductive material include Si, Ge, zinc oxide, cadmium sulfide, titanium oxide, selenium, cadmium selenide, zinc selenide or lead oxide, Se—Te alloy, As ₂ S ₃ , As.
Examples include chalcogen alloys such as ₂ Se ₃ . Examples of the organic photoconductive material include photoconductive cyanine pigments, photoconductive quinoline pigments, photoconductive phthalocyanine pigments, photoconductive pyrylium salt pigments, substituted vinyl oxazoles, triphenylamine derivatives, anthracenes, and benzocondensates. Heterocycles, pyrazoline or imidazole derivatives, oxadiazole derivatives, vinyl aromatic polymers and their copolymerization products, fluorenone derivatives,
Polyarylalkanes such as triarylmethane leuco dyes and squaric acid derivative dyes, perylene, tetracene, carbazole, tetrabenzyl-p-phenylenediamine, squarylium, indigo, dimethylperimide, polyzenyltetracene, polyzenylperylene Examples thereof include acylhydrazone derivatives, benzthiazole derivatives, tetracyanopyrene, chlorocyan blue and the like. You may use these together. As the binder, use a material known as a binder for silicone resin, polystyrene, polyacrylic acid or polymethacrylic acid ester, polyvinyl acetate, polyvinyl chloride, polyvinyl butyral and their derivatives and other photoconductive layers. You can The amount of the photoconductor in the photoconductive layer is such that the weight ratio of the photoconductive substance to the binder is, for example, in the range of 3: 1 to 20: 1, but is not particularly limited in the present invention. .. Further, if necessary, a sensitizer and a coating aid and other additives used when coating can be added. The thickness of this photoconductive layer is usually about 5 to 30 μm, but is not particularly limited in the present invention. Further, in order to improve the adhesive force between the photoconductive layer and the under layer, the surface of the under layer is previously formed, for example, in US Pat.
As described in Japanese Patent No. 1,908, it is preferable to perform surface treatment such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet treatment, ozone treatment, and plasma treatment.

The lithographic printing plate precursor of the present invention may be produced by a technique known in the field of manufacturing electrophotographic lithographic printing plate precursors of this type, and examples of dispersion methods include ball mill, colloid mill, ultrasonic disperser, and 3 This roll mill, grain mill,
A normal one such as a homogenizer or a homomixer can be used. As a coating method, an air knife coater,
A trailing grade coater, wire bar coater, reverse roll coater, kiss roll coater, fountain coater, etc. can be used.

The above-mentioned original plate of the present invention is made into a lithographic printing plate through the steps of ordinary charging, image exposure and development. Also,
It is also suitable for performing the above-described direct power supply type development.

[0020]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to this. Example 1 Using a fine paper of 85 g / m ² as a support, a composition (B-1) prepared by the following formulation (B-1) as an inner layer was first applied as a back layer with a wire bar, and then the temperature was changed. An inner layer having a thickness of 7 μm was formed by drying at 140 ° C. for 1 minute. Next, the composition (A-1) prepared by the following formulation (A-1) was similarly applied with a wire bar and then dried at a temperature of 140 ° C. for 1 minute to give a thickness of 3 μm.
A back layer was formed as the outermost layer of m. Outermost layer formulation (A-1) [Solid content weight ratio] Clay 58 Acrylic 34 (from emulsion) Polyvinyl alcohol 9 Melamine cross-linking agent 4.3 Pre-watered so that the total amount of solid content is 30% by weight. Was dissolved or dispersed in. Inner Layer Formulation (B-1) [Solid Weight Ratio] Clay 45 SBR (Tg 30 ° C.) 18 (from emulsion) The above was dissolved or dispersed in water in advance so that the total solid content would be 30 wt%. .. Next, a 5% aqueous solution of polyvinyl alcohol (PVA) was applied on the surface of the support with a wire bar to a dry film thickness of 8 μm, and then as the photoconductive layer, the following composition photoconductive layer composition (parts by weight): photoconductive oxidation Zinc (trade name: SAZEX 2000) 100 parts Acrylic resin (manufactured by Fuji Photo Film Co., Ltd.) 20 parts Rose Bengal 0.1 part Toluene 190 parts, dried, and provided with a dry coating material of 23 g / m ² to prepare the electron of the present invention. An original plate for photographic planographic printing was obtained.

The dehumidifying speed of each back layer of the obtained electrophotographic lithographic printing plate precursor was measured. The outermost layer was 0.047 g / m ² · min, and the inner layer was 0.011 g / m.
It was ² · min. Two of these original plates (samples) were stacked face up, and the bottom area was 5 cm ² and the weight was 20
A g piece of aluminum metal was placed, the upper sample was held stationary, and only the lower sample was slid to force viscous. Next, the sample taken out below is used as an original plate to make a plate with an ELP-310 electrophotographic plate making machine manufactured by Fuji Photo Film Co., Ltd., and then an etching treatment liquid E2 manufactured by Fuji Photo Film Co., Ltd. is immersed in cotton to etch the surface. However, printing was performed using a Ryobi AD80 type printer (manufactured by Ryobi Co., Ltd.), there was no smear stain, and the waviness evaluation (shown in the same manner as in FIG. 2) was a pass (◯).

Comparative Example 1 In Example 1, the formulation of the outermost layer of the back layer was as follows (A-
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic polymer in 2) was not used. At this time, the dehumidifying speed of the outermost layer is 0.050 g / m ² · min,
The inner layer was 0.011 g / m ² · min. Outermost layer formulation (A-2) [weight ratio of solid content] Clay 58 acrylic 43 melamine cross-linking agent 4.3 The above components were previously dissolved or dispersed in water so that the total solid content was 30% by weight. Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As a result, as shown in Table 1, scorching stains were generated.
The wavy evaluation was successful.

Comparative Example 2 In Example 1, the inner layer formulation of the back layer was as follows (B-
Example 1 except that the high dehumidifying speed of 2) was used.
A lithographic printing plate precursor was prepared in the same manner as in. At this time, the dehumidifying speed of the outermost layer was 0.47 g / m ² · min, and the inner layer was 0.42 g / m ² · min. Outermost layer formulation (A-1) Inner layer formulation (B-2) Clay 58 Acrylic 43 Melamine cross-linking agent 4.3 The above components were previously dissolved or dispersed in water so that the total solid content would be 30% by weight. When the obtained original plate was printed and evaluated in the same manner as in Example 1, as shown in Table 1, no scorching stain was generated, but the wavy evaluation was x.

Comparative Example 3 The following formulation (C) was used as a back layer on the same support as in Example 1.
-1), a composition prepared from a material obtained by mixing (A-1) and (B-1) is applied, dried at a temperature of 135 ° C. for 1 minute, and has a thickness of 10 μm and a dehumidification speed of 0.35 g. / M
Example 1 except that only one back layer of ² · min was used.
A lithographic printing plate precursor was prepared in the same manner as in. 1 layer mixed back layer formulation (C-1) [Solid content weight ratio] Clay 103 Acrylic 34 SBR resin (Tg 30 ° C) 18 Polyvinyl alcohol 9 Melamine cross-linking agent 4.6 or more Finally, the total solid content is 30 weight. It was previously dissolved or dispersed in water so that the concentration became%. When the obtained original plate was printed and evaluated in the same manner as in Example 1, as shown in Table 1, there was only a slight amount of kosre stain, but the wavy evaluation was x.

Example 2 In Example 1, the outermost layer had a dry thickness of 5 μm.
(Dehumidification speed 0.38 g / m ² · min), the inner layer has a dry thickness of 5 μm (dehumidification speed 0.16 g / m ² · mi)
An electrophotographic printing plate precursor according to the present invention was prepared in the same manner as in Example 1 except that n) was used. Outermost layer prescription (A-1) Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As shown in Table 1, no smearing was observed and the wavy evaluation was acceptable. there were.

Example 3 In Example 1, the outermost layer had a dry thickness of 6 μm.
(Dehumidification speed 0.035 g / m ² · min), the inner layer has a dry thickness of 4 μm (dehumidification speed 0.025 g / m ² · min)
min) was prepared in the same manner as in Example 1 to prepare an electrophotographic printing plate precursor of the present invention. Outermost layer prescription (A-1) Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As shown in Table 1, no smearing was observed and the wavy evaluation was acceptable. there were.

[0027]

[Table 1] Evaluation Criteria ○: No Kosre stains occurred △: Slight Kosle stains occurred ×: Kosure stains occurred

From the results of the above Examples and Comparative Examples, the back layer is made to be a multi-layer and the outermost layer contains a hydrophilic polymer,
Only when the inner layer has a dehumidifying speed of 0.03 g / m ² · min or less, it is possible to achieve both conflicting effects of preventing the occurrence of kosure stains and preventing waviness (ruled line bending) even when the environment changes. It will be understood that

Examples 4 to 6 and Comparative Examples 4 to 6 The outermost layer of the back layer was made into each of the following formulations (A-3) and (A-4).
And each of the following formulations of the inner layer of the back layer (B
-3) or (B-4) or as a backing layer having a one-layer structure according to the following formulation (C-1), for electrophotographic lithographic printing with a dry thickness and a dehumidifying speed shown in Table 2. Original plates were prepared by a method according to Examples 1 to 3 and Comparative Examples 1 to 3. As the conductive fine powder, Dento WK-100W manufactured by Otsuka Chemical Co., Ltd. was used. The dry layer thickness and dehumidification speed of each layer were as shown in Table 2. Outermost layer formulation (A-3) [Solid content weight ratio] Clay 58 Conductive fine powder 14 Acrylic 34 (from emulsion) Starch 9 Melamine cross-linking agent 4.3 The total solid content finally becomes 30% by weight. Was previously dissolved or dispersed in water. Inner Layer Formulation (B-3) [Solid Weight Ratio] Clay 45 SBR (Tg 30 ° C.) 18 (from emulsion) The above was dissolved or dispersed in water in advance so that the total solid content would be 30 wt%. .. Outermost layer formulation (A-4) [Solid content weight ratio] Clay 58 Conductive fine powder 14 Acrylic 43 (from emulsion) Melamine cross-linking agent 4.3 The above are finally added so that the total solid content becomes 30% by weight. It was previously dissolved or dispersed in water. Inner Layer Formulation (B-4) [Solid Weight Ratio] Clay 58 Acrylic 43 Melamine Crosslinking Agent 4.3 The above components were previously dissolved or dispersed in water so that the total solid content would be 30% by weight. 1-layer mixed back layer formulation (C-1) [Solid content weight ratio] Clay 103 Conductive fine powder 14 Acrylic 34 SBR resin (Tg 30 ° C) 18 Polyvinyl alcohol 9 Melamine cross-linking agent 4.3 Finally, the solid content Was previously dissolved or dispersed in water so that the total amount of the above was 30% by weight.

The obtained electrophotographic lithographic printing plates of Examples 4 to 6 and Comparative Examples 4 to 6 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0031]

[Table 2]

From the results shown in Table 2, it can be seen that the original plate having a back layer having a two-layer structure of A layer and B layer within the limited range of the present invention can satisfy both characteristics of preventing smearing and passing ripple evaluation. .. In this way, the type in which the conductive fine powder is added to the A layer of the back layer is also suitable for the direct power supply type development.

As described above, according to the present invention, a printing original plate for electrophotographic plate making can be prepared without producing scorching stains during production, and moreover, when printing using the original plate of the present invention, undulation It is possible to print a large number of sheets without (curved line bending). Further, the original plate of the present invention is very suitable for development by a direct power feeding system as well as by ordinary electrophotography.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the thickness of the outermost back layer of the present invention and the occurrence of scorching stains.

FIG. 2 is a graph showing the relationship between the dehumidification speed of the inner layer of the back layer and the corrugation (curved line bending) of the present invention.

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[Procedure amendment]

[Submission date] August 5, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

By the way, since the lithographic printing plate precursor is usually wound in a roll shape, the back layer and the printing surface (top layer) come into contact with each other, so that a composition for forming a back layer, such as water resistance, is used. The substance or the like for application is transferred to the top layer. The water resistance improver is a problem that occurs dirt (rubbing referred to as dirt) on printed materials when attached to a portion (non-image portion) having no toner image. If the amount of waterproofing agent added to the back layer is reduced in an attempt to prevent this, the waterproofness will naturally decrease, and for example, the moisture in the atmosphere will be absorbed while nipping in the plate making machine, and the support will stretch and become wavy. and, coming out is a problem that such a linear portion When you print a master from being printed wavy. That is, both of waterproof and securing rubbing stain prevention (prevention of the support modified by environmental changes) has been difficult. Further, the back layer is required to have a function of easily adhering to the plate cylinder (fitting property), and also a function of guaranteeing printing workability such as displacement from the plate cylinder, and printability. Satisfaction is required. Therefore, the object of the present invention is to have good characteristics against scorching stains, and to prevent problems such as the original plate stretching and wavy due to environmental changes in the plate making machine, and the fact that ruled lines are bent and printed as a real damage. An object of the present invention is to provide an electrophotographic lithographic printing plate precursor that simultaneously solves printing performance such as possible. Further, another object of the present invention is for electrophotographic lithographic printing which can be applied to development of ordinary electrophotographic plate making as well as development of a direct power feeding method, and which can satisfy both the above-described smear stain and printing performance. To provide the original version.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In the present invention, since the outermost layer A contains a hydrophilic polymer, a large amount of the hydrophilic polymer is transferred to the top even when the back layer surface comes into contact with the top layer in a roll state. it is possible to prevent the rubbing stain generation when there a layer that is. Hydrophilic colloid particles and the like may be added to the layer A for the purpose of further increasing the anti-corrosion ability. Further, the back layer B of the present invention has a dehumidifying speed of 0.0.
By providing an inner layer as low as 3 g / m ² · min or less (excluding those having a water absorption by the cup method of 25 g / m _{2 ■} (45 minutes value) or less), the support can be retained against environmental changes. Humidity is unlikely to be affected, sufficient water resistance and waterproofness can be secured, and it is possible to prevent deformation of the support during the plate-making process and to prevent lines such as ruled lines from being wavy printed. Further, the layer A has the main purpose of preventing the occurrence of scorching stains, but the layer B can maintain the performance required as a printing plate. The B layer may have a single-layer structure, but may have a plurality of layers. A hydrophilic polymer binder such as an organotitanium compound may be added to one or both layers for the purpose of improving the adhesion of the A layer to the B layer. As described above, according to the present invention, it is possible to achieve both the contradictory functions of preventing smearing and waterproofing.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Comparative Example 2 In Example 1, the back layer inner layer formulation was as follows (B-
Example 1 except that the high dehumidifying speed of 2) was used.
A lithographic printing plate precursor was prepared in the same manner as in. The outermost at this time
The dehumidification speed of the layer0.047g / m2 ■. min, inner layer
Is 0.042g / m^Two・ It was min. Outermost layer prescription (A-1) Inner layer prescription (B-2)(Solid weight ratio)  Clay 58 Acrylic 43 Melamine cross-linking agent 4.3 The above is finally adjusted so that the total solid content becomes 30% by weight.
It was previously dissolved or dispersed in water. Perform on the obtained original plate
When printed and evaluated in the same manner as in Example 1, as shown in Table 1.
There was no stain on the surface, but the wavy evaluation was ×.
It was.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

Comparative Example 3 The following formulation (C) was used as a back layer on the same support as in Example 1.
-1), a composition prepared from a material obtained by mixing (A-1) and (B-1) is applied, dried at a temperature of 135 ° C. for 1 minute, and has a thickness of 10 μm and a dehumidification speed of 0.035. g /
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that only one back layer of m ² · min was used. 1 layer mixed back layer formulation (C-1) [Solid content weight ratio] Clay 103 Acrylic 34 SBR resin (Tg 30 ° C) 18 Polyvinyl alcohol 9 Melamine cross-linking agent 4.6 or more Finally, the total solid content is 30 weight. It was previously dissolved or dispersed in water so that the concentration became%. When the obtained original plate was printed and evaluated in the same manner as in Example 1, as shown in Table 1, there was only a slight amount of kore stain, but the wavy evaluation was x.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Example 2 In Example 1, the outermost layer had a dry thickness of 5 μm.
(Dehumidification speed 0.038 g / m ₂ ·· min), the inner layer has a dry thickness of 5 μm (dehumidification speed 0.016 g / m ² ·
min) except that the flatness of the present invention is the same as in Example 1.
An original plate for printing was prepared. Outermost layer prescription (A-1) Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As shown in Table 1, no smearing was observed and the wavy evaluation was acceptable. there were.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

Example 3 In Example 1, the outermost layer had a dry thickness of 6 μm.
(Dehumidification speed 0.035 g / m ² · min), the inner layer has a dry thickness of 4 μm (dehumidification speed 0.025 g / m ² · min)
min) except that the flatness of the present invention is the same as in Example 1.
An original plate for printing was prepared. Outermost layer prescription (A-1) Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As shown in Table 1, no smearing was observed and the wavy evaluation was acceptable. there were. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

By the way, the inventors of the present invention changed the conventional developing method of an electrophotographic printing plate precursor to a method of passing a developing solution between electrodes to allow a master to pass therethrough, and a side opposite to a printing surface. of using the conductor in place of the electrode, to develop a wet developing method according to the so-called direct feeding system for developing while feeding electrons to support the back side from the conductor directly, already Patent Rights
It is proposed in Japanese Patent Laid-Open No. 1-26043 . As a method for improving this, the surface electric resistance of the back layer of the support having a polyolefin laminate layer on both sides of the support is 1 × 10 5.
By providing a layer with a friction resistance of ¹⁰ Ω or less and a greater friction resistance than the polyolefin laminate layer, the winding and fixing on the drum of the printing machine will be accurate, printing misalignment will be prevented and good electrophotographic plate making will be possible. An original plate that can also be used has been proposed (Japanese Patent Laid-Open No. 2-84665).
Further, an under layer and a photoconductive layer are provided on the surface of the support, and a back layer is provided on the back surface, and the surface resistivity of the under layer is 1 × 10 ⁸
-1 × 10 ¹⁴ , and by setting the back layer to 1 × 10 ¹⁰ or less, accurate, good and quick, no pinholes are generated on a solid screen by any wet development of conventional method and direct power feeding method. An original plate capable of forming a uniform image and a developing method thereof have been proposed (JP-A-2-132464).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In the present invention, since the outermost layer A contains a hydrophilic polymer, a large amount of the hydrophilic polymer is transferred to the top even when the back layer surface comes into contact with the top layer in a roll state. It is possible to prevent the occurrence of Kosure stains when the layer is provided. Hydrophilic colloid particles and the like may be added to the layer A for the purpose of further increasing the anti-corrosion ability.
Further, the back layer B of the present invention has a dehumidification speed of 0.
By providing an inner layer as low as 03 g / m ² · min or less (excluding those having a water absorption by the Cobb method of 25 g / m ² (45 minutes value) or less), the humidity possessed by the support can be improved against environmental changes. Is less likely to be affected, and sufficient water resistance and waterproofness can be secured, and it is possible to prevent the deformation of the support during the plate-making process and the wavy printing of straight lines such as ruled lines. Further, the layer A has the main purpose of preventing the occurrence of scorching stains, but the layer B can maintain the performance required as a printing plate. The B layer may have a single-layer structure, but may have a plurality of layers. In addition, for the purpose of improving the adhesion between the A layer and the B layer, a hydrophilic polymer binder such as an organic titanium compound, a silane coupling agent ((RO) ₃ -Si-X), titanium
A salt-based coupling agent or the like may be added to one or both layers. As described above, according to the present invention, it is possible to achieve both the contradictory functions of preventing smearing and waterproofing.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The back layer of the present invention will be described in more detail below. The layer A of the present invention is a layer containing a hydrophilic polymer. In FIG. 1, a layer B according to the present invention is formed on a support, and the composition of the formulation (A-2) of Comparative Example 2 described later as the layer A (containing no hydrophilic polymer), (A-2). 2 of polyacrylic acid ester weight composition ratio of 4 in 3% in the formulation of,
A photoconductive layer having a common composition was further formed on each of the samples prepared by changing the thickness of each of 5 and 10% of polyvinyl alcohol (abbreviated as PVA) which is a hydrophilic polymer and having a composition The results obtained by printing the obtained printing plate for electrophotographic plate making and examining the occurrence of smear stains are shown. In Figure 1, ○ means no occurrence, △ means slight occurrence, ×
Means occurrence. As is clear from FIG. 1, as the PVA substitution amount (S) increases, the occurrence of scorching stains decreases.
It can also be seen that the A layer is effective even if it is considerably thin, and that if it exceeds 1 μm, the effect is hardly changed even if the thickness is further increased.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

As the hydrophilic polymer of the layer A of the present invention, any known natural or synthetic hydrophilic polymer may be used. Specifically, for example, in addition to normal lime-processed gelatin, acid-processed gelatin, modified gelatin, gelatin such as derivative gelatin, albumin, sodium alginate,
Gum arabic, cellulose, hydroxyethyl cellulose, water soluble derivatives such as cellulose and starch such as carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, styrene - one such hydrophilic polymers such as maleic anhydride copolymer Or 2
More than one species can be used. Hydrophilic colloid particles (fine particles of hydrophilic substances such as silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zeolite, etc. dispersed stably in a colloid)
If added, the anti-Korea effect is further improved.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

As the material for forming the B layer, various water resistant materials, water resistant organic solvent resistant materials, and synthetic emulsions described above as the material for forming the A layer can be used, and a water-soluble polymer compound can also be used. .. Examples of the water-soluble polymer compound include starch or a water-soluble derivative thereof, a water-soluble cellulose derivative, casein, polyvinyl alcohol, a styrene maleic anhydride copolymer, and a vinyl acetate-maleic anhydride copolymer. .. Also in this case, the amount used is selected so that the water absorption of the layer B is 25 g / m ² or less. These B layer forming material is also possible to use in combination, dispersing agent, if necessary, a leveling agent, a point that can be added a crosslinking agent and the like are the same as those in the A layer .. Further, as described above, the adhesion of both layers can be improved by adding a hydrophilic polymer binder such as an organic titanium compound to one or both of the A layer and the B layer.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

As the water-absorbent support of the present invention, any of the known supports used in this type of electrophotographic lithographic printing plate precursor can be used. For example , a substrate such as paper or a plastic sheet, a substrate obtained by impregnating these with a low resistance substance to conduct electrical treatment, a substrate provided with a water-resistant adhesive layer or at least one precoat layer, Al It is possible to use, for example, a laminate of paper on which electroconductive plastic having a base material vapor-deposited with the above is laminated. Specific examples of the conductive substrate or the conductive material include Yukio Sakamoto, "Electrophotography" 14, (No.1), p2-11 (1975), Hiroyuki Moriga, "Introduction to Special Paper Chemistry," Polymer Society (1975),
MF Hoover, J. Macromol. Sci. Chem., A-4
(6), p1327 to 1417 (1970) and the like are used.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

[0020]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to this. Example 1 Using a fine paper of 85 g / m ² as a support, a composition (B-1) prepared by the following formulation (B-1) as an inner layer was first applied as a back layer with a wire bar, and then the temperature was changed. An inner layer having a thickness of 7 μm was formed by drying at 140 ° C. for 1 minute. Next, the composition (A-1) prepared by the following formulation (A-1) was similarly applied with a wire bar and then dried at a temperature of 140 ° C. for 1 minute to give a thickness of 3 μm.
A back layer was formed as the outermost layer of m. Outermost Formulation (A-1) [solid content weight ratio] Clay 58 Polyacrylic acid ester 34 (Emarujo down) so that the total amount of the finally solids polyvinyl alcohol 9 melamine crosslinking agent 4.3 or more is 30 wt% Was previously dissolved or dispersed in water. Inner layer formulation (B-1) the total amount of [solid content weight ratio] Clay 45 SBR (Tg 30 ° C.) 18 final solid content (Emarujo down) above is dissolved or dispersed in water beforehand so as to be 30 wt% .. Next, a 5% aqueous solution of polyvinyl alcohol (PVA) was applied on the surface of the support with a wire bar to a dry film thickness of 8 μm, and then as the photoconductive layer, the following composition photoconductive layer composition (parts by weight): photoconductive oxidation Zinc (trade name SAZEX 2000) 100 parts Acrylic resin (manufactured by Fuji Photo Film Co., Ltd.) 20 parts Rose Bengal 0.1 part Toluene 190 parts, dried, and provided with a photoconductive layer having a dry coating amount of 23 g / m ^2. An original plate for electrophotographic lithographic printing of the present invention was obtained.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

Comparative Example 1 In Example 1, the formulation of the outermost layer of the back layer was as follows (A-
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic polymer in 2) was not used. At this time, the dehumidifying speed of the outermost layer is 0.050 g / m ² · min,
The inner layer was 0.011 g / m ² · min. Outermost layer formulation (A-2) [Solid content weight ratio] Clay 58 Polyacrylic acid ester 43 Melamine cross-linking agent 4.3 Dissolve or disperse the above in water in advance so that the total solid content will be 30% by weight. did. Inner layer prescription (B-1) The obtained original plate was printed and evaluated in the same manner as in Example 1. As a result, as shown in Table 1, scorching stains were generated.
The wavy evaluation was successful.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Comparative Example 2 In Example 1, the inner layer formulation of the back layer was as follows (B-
Example 1 except that the high dehumidifying speed of 2) was used.
A lithographic printing plate precursor was prepared in the same manner as in. At this time, the dehumidifying speed of the outermost layer was 0.047 g / m ² · min, and the inner layer was 0.042 g / m ² · min. Outermost layer formulation (A-1) Inner layer formulation (B-2) [Solid content weight ratio] Clay 58 Polyacrylic acid ester 43 Melamine cross-linking agent 4.3 The above are finally added so that the total amount of solid content is 30% by weight. Was previously dissolved or dispersed in water. When the obtained original plate was printed and evaluated in the same manner as in Example 1, as shown in Table 1, no scorching stain was generated, but the wavy evaluation was x.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

Comparative Example 3 The following formulation (C) was used as a back layer on the same support as in Example 1.
-1), a composition prepared from a mixture of (A-1) and (B-1) is applied and dried at a temperature of 135 ° C. for 1 minute to give a thickness of 10 μm and a dehumidification speed of 0.035 g. /
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that only one back layer of m ² · min was used. 1 layer mixed back layer formulation (C-1) [weight ratio of solid content] clay 103 polyacrylic acid ester 34 SBR resin (Tg 30 ° C) 18 polyvinyl alcohol 9 melamine cross-linking agent 4.6 or more finally the total amount of solid content Was previously dissolved or dispersed in water so as to be 30% by weight. When the obtained original plate was printed and evaluated in the same manner as in Example 1, as shown in Table 1, there was only a slight amount of kore stain, but the wavy evaluation was x.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Examples 4 to 6 and Comparative Examples 4 to 6 The outermost layer of the back layer was made into each of the following formulations (A-3) and (A-4).
And each of the following formulations of the inner layer of the back layer (B
-3) or (B-4) or as a backing layer having a one-layer structure according to the following formulation (C-1), for electrophotographic lithographic printing with a dry thickness and a dehumidifying speed shown in Table 2. Original plates were prepared by a method according to Examples 1 to 3 and Comparative Examples 1 to 3. As the conductive fine powder, Dento WK-100W manufactured by Otsuka Chemical Co., Ltd. was used. The dry layer thickness and dehumidification speed of each layer were as shown in Table 2. Outermost Formulation (A-3) [solid content weight ratio] Clay 58 conductive fine powder 14 polyacrylic acid ester 34 (Emarujo down) the total amount of 30 wt finally solids starch 9 melamine crosslinking agent 4.3+ It was previously dissolved or dispersed in water so that the concentration became%. Inner layer formulation (B-3) the total amount of [solid content weight ratio] Clay 45 SBR (Tg 30 ° C.) 18 final solid content (Emarujo down) above is dissolved or dispersed in water beforehand so as to be 30 wt% .. The outermost layer formulation (A-4) [solid weight ratio] Clay 58 conductive fine powder 14 polyacrylic acid ester 43 (Emarujo down) the total amount of the finally solids melamine crosslinking agent 4.3 or 30 wt% It was previously dissolved or dispersed in water so that Inner layer formulation (B-4) [Solid content weight ratio] Clay 58 Polyacrylic acid ester 43 Melamine cross-linking agent 4.3 The above components were dissolved or dispersed in water in advance so that the total solid content would be 30% by weight. .. 1 layer mixed back layer formulation (C-1) [Solid content weight ratio] Clay 103 Conductive fine powder 14 Polyacrylic acid ester 34 SBR resin (Tg 30 ° C) 18 Polyvinyl alcohol 9 Melamine cross-linking agent 4.3 or more final In advance, it was dissolved or dispersed in water so that the total amount of solid content was 30% by weight. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 10, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

1. An electrophotographic lithographic printing plate precursor comprising at least a photoconductive layer on one side of a support and a back layer on the other side, wherein the back layer contains a hydrophilic polymer. Outermost layer and an inner layer having a dehumidifying speed of 0.03 g / m ² · min or less [however, the water absorption by the Cobb method is 25 g / m ² (4
5 minutes value) excluding the following]]. An electrophotographic lithographic printing plate precursor.