JPH0289062A - Master plate for printing - Google Patents

Abstract

PURPOSE:To lower the toxicity of a photoconductor layer and to obtain good photographic characteristics even if the layer is not subjected to intensive drying by applying and forming the photoconductor layer on a substrate by using a solvent contg. propylene glycol monomethyl ether acetate as a coating solvent. CONSTITUTION:The photoconductor layer is applied and formed on the substrate by using the solvent contg. the propylene glycol monomethyl ether acetate as the coating solvent. A photoconductor pigments such as zinc oxide are used alone or in combination as the photoconductive material to be used for the photosensitive liquid for forming the photoconductor layer. Org. carboxylic acid such as benzoic acid or the anhydride thereof which is capable of making effective sensitization and does not hinder the removal of the photoconductor layer by an alkaline soln. is preferably used as a sensitizer. Further, an alkaline soluble resin, for example, phenolic resin and/or acrylic resin, etc., are used as a binder resin. The toxicity is lowered in this way and the good photographic characteristics are obtd. even if the photoconductor layer is not subjected to intensive drying.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a printing original plate, and more particularly to a photosensitive layer of an electrophotographic printing original plate having a photoconductor layer as a photosensitive layer.

BACKGROUND OF THE INVENTION 1 A printing original plate is generally prepared by dissolving a photoconductive substance, a binder resin, a sensitizer, etc. in a solvent (hereinafter referred to as a coating solvent), and filtering the solution as necessary. A method is known in which a photosensitive liquid is applied onto a surface-treated support by an appropriate method and then dried.

Conventionally, in this technology, diethylamine, dimethylformamide, tetrahydrofuran,
Cyclohexanone, phenol, cresol, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ethertate, ethylene glycol monoethyl ether acetate mixtures are used. There is.

However, when printing master plates are created using these conventional coating solvents, the coated printing master plates must be dried to a state close to absolute dryness (the final dry state where drying does not proceed any further). The original electrophotographic properties cannot be obtained and good plate making cannot be performed.

As a result, the drying load (energy required for drying) was large, and some solvents were highly toxic or had a pungent odor depending on the type of solvent.

[Object of the Invention] The present invention rectifies such conventional drawbacks, and provides a coating solution that uses a coating solvent of low toxicity and that allows original electrophotographic properties to be obtained without intense drying such as absolute drying. The purpose is to provide original printing plates.

[Structure of the Invention, 1 The object of the present invention is achieved by using a solvent containing propylene glycol monomethyl ether acetate as a coating solvent.

The present invention provides a printing original plate having a photoconductor layer on a support, and in which a printing plate is prepared by removing the photoconductor layer in a non-image area after toner image formation, and in which the photoconductor layer is coated. The present invention relates to a printing original plate formed by coating on the support using a solvent containing propylene glycol monomethyl ether acetate as a solvent.

The present invention will be described below, but the present invention is not limited thereto.

As the photoconductive substance used in the present invention,
-2780, 44-12671, 46-300
No. 35, No. 44-16474, No. 48-30513, No. 50-7434, JP-A-47-18543, No. 47-18544, No. 47-30330, No. 47-
No. 37543, No. 49-11136, No. 49-991
No. 42, No. 51-109841, No. 54-13463
No. 2, No. 55-11715, No. 55-105254, No. 55-153948, No. 55-161250,
No. 56-1944, No. 56-2352, No. 56-9
No. 752, No. 56-19063, No. 56-29250
No. 56-69644, No. 56-80050, No. 59-125751, No. 59-176756, No. 6
No. 0-17751, No. 60-17752, No. 60-1
No. 7753, No. 60-17754, No. 60-1775
No. 5, No. 60-17756, No. 60-17757,
No. 60-17758, No. 60-17759, No. 60
-17760, 60-17761, 60-17
No. 762, No. 60-35750, No. 61-67869
Perylene pigments, quinacridone pigments, bisbenzimidazole pigments, aromatic polycondensed ring compounds, monoazo pigments, disazo pigments, trisazo pigments, metal or nonmetallic) talocyanine pigments, zinc oxide, etc., described in No. 61-67870, etc. These photoconductive pigments can be used alone or in combination of two or more.

It is also possible to use soluble photoconductive substances, such as those disclosed in Japanese Patent Publication No. 37-171.
No. 62, No. 38-6961, No. 38-7758, No. 39-12703, No. 46-39405, JP-A-5
No. 0-19509, No. 50-19510, No. 52-2
No. 437, No. 54-19803, No. 56-66863
No. 56-130766, No. 57-88457,
No. 57-161863, No. 58-2854, No. 58
-100862, 58-118658, 59-
No. 121058, No. 59-121059, No. 59-1
No. 21060, No. 59-121061, No. 59-12
No. 8559, No. 59-121060, No. 59-121
No. 061, No. 59-128559, No. 59-1285
No. 60, No. 59-128561, No. 59-14735
No. 5, No. 59-151157, No. 59-152456
Oxazole compounds, oxanediazole compounds, diphenylmethane compounds, triphenylmethane compounds, anthracene, etc. These include carbazole-based compounds, pyrene-based compounds, hydrazone-based compounds, and the like.

Furthermore, in the present invention, a sensitizer can be used in combination for the purpose of adjusting sensitivity or photosensitive wavelength.
1, 47-30332, 55-161250, etc., JP-A-47-3033
Electron-accepting substances described in No. 0, No. 55-153948, etc., and xanthine dyes such as rose bengal, eosin S1 fluorescein, and 70 xin; Rain dye: Alquazurin 2G, Bontasil Briant Blue FCF
, triphenylmethane dyes such as acid violet 6B, diphenylmethane dyes such as niolamine, acridine dyes such as niacridine yellow, acridine orange:
There are various dyes such as rhodamine dyes such as sulforodamine B1 acid eosin G and the like.

Among these, organic carboxylic acids such as benzoic acid, phthalic acid, maleic acid, and fumaric acid, and their Anhydrides are particularly preferred.

The binder resin used in the photoconductor of the present invention is an alkali-soluble resin, such as JP-A-54-13463.
2, No. 55-105254, etc., and/or acid group-containing resins such as acrylic acid resin, crotonic acid resin, phthalic acid resin, maleic acid resin, etc.
Relatively poorly alkali-soluble resins can also be used in combination, as long as they do not inhibit removal of the photoconductor layer by an alkaline aqueous solution. These resins include polystyrene and styrene.
Hydrocarbon polymers such as butadiene copolymers and polyisobutylene; Vinyl resins such as polyvinyl chloride, chlorinated polyethylene, polyvinyl acetate, polyvinyl acetal, polyvinyl butyral, and polyvinyl ether; silicone resins;
Polyamide resins: polyurethane resins; urea resins; melamine resins; polycarbonate-modified or unmodified natural resins such as rosin and balsam.

Supports used in the printing original plate of the present invention include aluminum plates, zinc plates, iron plates surface-treated with chrome plating, copper-aluminum plates, copper-stainless steel plates, chrome-copper-aluminum plates, chrome-lead plates, etc. - Using a conductive substrate with a hydrophilic surface, such as a tri-metal plate such as an iron plate, a chromium-copper-stainless steel plate, a paper containing a conductive agent, or a three-layer plate in which a resin layer is sandwiched between metal plates such as aluminum. Can be done.

Particularly preferably, the aluminum layer has an aluminum layer on at least the surface, the surface of the aluminum layer is grained, and the center line average roughness (Ra) of the grained surface is 0.2 to 0.2.
The support is in the range of 0.8 μm.

More preferably, the aluminum layer has an aluminum layer on at least the surface, the surface of the aluminum layer is grained, then hydrophilized (for example, anodized), and the surface is further sealed. Surface center line average roughness (Ra)
is a support in the range of 0.2 to 0.8 μ-.

Graining of the surface of the aluminum layer includes electrolytic polishing in an electrolytic solution such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc., or mechanical polishing methods such as ball polishing, brush polishing, press polishing, and honing. In addition, in the oxide film forming treatment following graining, the amount of oxide film is usually lO~5
0mg/dm2, more preferably 20-30mg
/dm" and is preferably an aluminum plate which has been further sealed with hot water, a silicate, a phosphate, a fluorosilicate, or the like.

Here, center line roughness (Ra) is German standard DIN47
68, it is the arithmetic mean of the absolute value of the distance from the center line of the roughness profile to each point on the profile, with the horizontal center line as the X axis and the vertical direction as the Y axis. When the point on the roughness profile is expressed as (X, Y), Ra is calculated using the following formula for the measurement length Qm.
The value is expressed in μm.

This value can be measured, for example, with a Perthometer S 5 P manufactured by Perthen.

The entire support body of the aluminum plate does not necessarily need to be made of aluminum, and it is sufficient if the surface of the support body is an aluminum plate. For example, it may be a multilayer board such as a two-layer board such as aluminum-paper or aluminum-resin, or a three-layer board such as aluminum-gi-aluminum or aluminum-resin base-aluminum, but in these cases, the gi or resin base is It is desirable to contain a conductive agent.

To prepare the printing original plate of the present invention, the photoconductive substance, binder resin, sensitizer, etc. described above are dissolved or dispersed in a solvent (coating solvent) containing propylene glycol monomethyl ether acetate. The photosensitive liquid for forming a photoconductor layer is coated on the above-mentioned surface-treated support by a method such as roll coater coating, applicator coating, wire bar coating, calendar coating, whirler coating, etc. to determine the film thickness after drying. It is applied to a thickness of about 2 to 1θμ, and then dried.

A printing original plate, such as the printing original plate of the present invention, in which the photoconductor layer in the non-image area is removed after toner image formation to produce a printing plate, depends on the type of photoconductive substance used in the photoconductor layer. It can be classified into two types.

That is, the printing original plate (first type) mainly uses a photoconductive substance that has a completely soluble solvent (dissolved photoconductive substance), and the first type mainly uses a pigment-based photoconductive substance that has almost no soluble solvent. This is the original printing plate (second type).

When producing the first type of printing original plate in the present invention, when the photoconductive substance used is soluble in propylene glycol monomethyl ether acetate, this substance alone is used as a coating solvent. On the other hand, if the photoconductive substance used is not soluble in propylene glycol monomethyl ether acetate but is soluble in other solvents, the minimum amount necessary to dissolve the propylene glycol monomethyl ether acetate and the photoconductive substance is required. Use the following solvents together.

When preparing the second type of printing original plate, propylene glycol monomethyl ether acetate alone is used as a coating solvent, and a photosensitive liquid for forming a photoconductor layer is prepared by dispersion.

In addition, when producing either the first type or the second type of printing plate, if the binder resin used is poorly soluble in propylene glycol monomethyl ether acetate, the necessary minimum amount of solvent that dissolves the resin well is required. A small amount is used with propylene glycol monomethyl ether acetate.

In the photosensitive liquid for forming a photoconductor layer of the present invention, the viscosity can be adjusted by the solid content concentration and the degree of dispersion of the photoconductive pigment (which can be expressed by the average particle size of the dispersed photoconductive pigment). Can be done. The higher the solid content concentration and the deeper the dispersion (smaller average particle size), the higher the viscosity.

The appropriate conditions for keeping the viscosity of the photosensitive liquid within a preferable range cannot be specified as they vary depending on the type of solvent and other conditions, but the solid content concentration is usually 10 to 30%.
, average particle size range of the dispersed photoconductive pigment from 2 to 0.1μ
within the range of The ratio of the photoconductive pigment to the binder resin may be determined according to a conventional method, and is 1:1 to 1:10 (weight ratio).
A range of is appropriate.

In order to make the printing original plate of the present invention into a printing plate, a charge is applied to the surface of the photoconductor layer of the printing original plate, imagewise exposure is performed, and then toner is attached and developed to form an image area. Then, the photoconductor layer corresponding to the non-image area is removed using, for example, an alkaline solution. For this removal, it is preferable to immerse the plate in an alkaline solution and then lightly rub the plate surface with a sponge, brush, etc. while rinsing with water. After the image area is formed by this elution, a printing plate is created by drying. At this time, if the non-image area is removed and then heated, the resin of the photoconductor layer in the image area will be better cured. As a result, printing durability can be further improved.

As the alkaline solution, a solution in which an inorganic and/or organic alkaline substance is dissolved in water and/or an organic solvent can be used. Inorganic alkaline substances include ammonia, alkali metal and alkaline earth metal hydroxides, such as ammonium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide or alkali phosphate salts, such as phosphoric acid. Examples include sodium, potassium phosphate or alkali silicate salts, such as sodium silicate and potassium silicate.

Organic basic substances include primary, secondary and secondary such as trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, butylamine, isobutylamine, dibutylamine, tributylamine, diisobutylamine, octylamine, dioctylamine. Tertiary lower saturated amines, as well as piperidine, N-methylpiperidine, N-ethylpiperidine, morpholine or amyls such as ethanolamine, jetanolamine, triethanolamine, N-methyljetanolamine, N-ethyljetanolamine. Examples include alcohols, diamines and polyamines such as ethylenediamine, diethylenetriamine, and triethylenetetramine, and lower substituted amides such as dimethylformamide.

Water and/or organic solvents are used as solvents for dissolving and diluting these alkaline substances. Examples of the organic solvent include ethers such as dibutyl ether, ethyl butyl ether, diisopropyl ether, dioxane, and tetrahydrofuran; acetone, methyl ethyl ketone,
Lower ketones such as dipropyl ketone; methyl acetate,
Lower esters such as ethyl acetate, butyl acetate, methyl propionate, methyl butyrate, ethyl butyrate, and methanol, ethanol, propatool, impropatol, imbutanol, ethylene glycol, polyethylene glycol, glycerin, ethylene glycol monomethyl ether, ethylene Examples include those containing an alcohol group such as glycol monoethyl ether.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited thereto.

Example-1 A dispersion liquid for forming a photoconductor layer was prepared according to the following procedure.

First, 4 parts by weight of an alkali-soluble resin having the following structural formula were mixed with 2 parts by weight of propylene glycol monomethyl ether acetate.
After dissolving to 0 parts by weight, it was filtered through a filter paper.

1 part by weight of ε-type copper phthalocyanine (Liophoton-EK, manufactured by Toyo Ink Co., Ltd.) was added to this solution,
The mixture was dispersed using glass beads for 1 hour to prepare a dispersion liquid. This dispersion was electrolytically polished until the surface average roughness (Ra) was 0.
．． After being grained to a depth of 6 μm, it was coated with a wire bar on aluminum that had been anodized and sealed with hot water to a film thickness of 25 μm, and placed in a dryer with an internal temperature of 100°C. It was dried by soaking it for 5 minutes to prepare a printing original plate.

Example-2 A dispersion liquid for forming a photoconductor layer was prepared according to the following recipe.

First, 6 parts by weight of a resin having the following structural formula was dissolved in 25 parts by weight of propylene glycol monomethyl ether acetate, and then filtered.

After dissolving in 75 parts by weight of rangelicol monomethyl acetate, ε-type copper phthalocyanine (Li
4.25 parts by weight of photon-EK) was added and dispersed for 8 hours using a sand grinder to prepare a dispersion for forming a photoconductor layer.

Add β-type copper phthalocyanine (manufactured by Ciba Geigy) to this solution.
After adding 1 part by weight of Chromo7tal Blue 4GN), dispersion was performed in a ball mill for 24 hours to obtain a dispersion. The surface average roughness (Ra) of this dispersion was determined by a liquid honing method.
After graining it to 0.4 μm, it was applied with a wire bar to a film thickness of 24 μm on an aluminum plate that had been anodized and sealed with an aqueous silicic acid solution, and the internal temperature was set to
The plate was dried by placing it in a dryer set at o'c for 5 minutes to prepare a printing original plate.

Example-3 It has the following structural formula. 5.25 parts by weight and 15.5 parts by weight of two types of polymer compounds, respectively, were added to the propylene dispersion in a grain chamber so that the surface had an average roughness (Ra) of 0.6 μm, and then anodized. A double roll type coater head with a drying zone of 15e and an internal temperature of 90°0 was installed on a coiled aluminum plate with a thickness of 0.3m+* which had been treated and further subjected to hot water sealing. A printing original plate was prepared by coating and drying the film at a coating thickness of 20 μm using a long coater at a speed of 2.0 m/min.

Example 4 An organic photoconductive substance having the following structural formula, a binder, and a sensitizer were dissolved in the following solvent to prepare a photosensitive liquid for forming a photoconductor layer.

After coating with a wire bar on a 0.3 mm thick aluminum plate with a film thickness of 25 μm, the internal temperature was 100°.
It was dried by placing it in a dryer set at C for 5 minutes to prepare a printing original plate.

Example 5 An organic photoconductive substance having the following structural formula, a binder, and a sensitizer were dissolved in the following solvent to prepare a photosensitive liquid for forming a photoconductor layer.

H3 Crystal Violet (sensitizer) 0.04 parts by weight 1.
2-dichloroethane:propylene glycol monomethyl ether acetate-1:2 (solvent) 16 parts by weight This solution was electrolytically polished to an average surface roughness (Ra) of 0.6 μm.
100,000 Rhodamine-B (sensitizer) 0.04 parts by weight 1.2-dichloroethane:propylene glycol monomethyl ether acetate - 16 parts by weight The solution was coated on the same support as in Example 1 with a coating film thickness of 25 μm4; immediately after coating, the internal temperature was 100'C! A printing original plate was prepared by drying the mixture by placing it in a dryer for 5 minutes.

Example 6 An organic photoconductive substance having the following structural formula, an inder, and a sensitizer were dissolved in the following solvent to prepare a photosensitive liquid for forming a photoconductor layer.

Rhodamine-B (sensitizer) 0.05 parts by weight 1
, 10 parts by weight of 2-dichloroethane (solvent) 15 parts by weight of propylene glycol monomethyl ether acetate (solvent) A printing original plate was prepared by applying the coating to a film thickness of 30 μm at a speed of 2.0 m/min using a long coater equipped with a double roll type coater head having a drying zone with a set length of 15+ m.

Comparative Example-l All the same as Example-1 except that ethylene glycol monoethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-1.
An original printing plate was prepared in the same manner as above.

Comparative Example-2 All the same as Example-1 except that propylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate.
A printing original plate was prepared in the same manner as in 1.

Comparative Example 3 A printing original plate was prepared in the same manner as in Example 2 except that tetrahydrofuran was used instead of propylene glycol monomethyl ether acetate.

Comparative Example 4 A printing original plate was prepared in the same manner as in Example 2 except that methyl ethyl ketone was used instead of propylene glycol monomethyl ether acetate.

Comparative Example-5 All the same as Example-3 except that ethylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-3.
An original printing plate was prepared in the same manner as above.

Comparative Example-6 All the same as Example-3 except that ethylene glycol monoethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-3.
An original printing plate was prepared in the same manner as above.

Comparative Example-7 All the same as Example-3 except that propylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate.
An original printing plate was prepared in the same manner as in 3.

Comparative Example 8 A printing original plate was prepared in the same manner as in Example 4 except that tetrahydrofuran was used instead of propylene glycol monomethyl ether acetate.

Comparative Example-9 All Example-4 except that propylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate.
A printing original plate was prepared in the same manner as in 4.

Comparative Example-1O All Example-5 except that ethylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-5.
An original printing plate was prepared in the same manner as above.

Comparative Example 11 A printing original plate was prepared in the same manner as in Example 5 except that methyl ethyl ketone was used instead of propylene glycol monomethyl ether acetate.

Comparative Example-12 All the same as Example-6 except that ethylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-6.
An original printing plate was prepared in the same manner as above.

Comparative Example-13 All the same as Example-6 except that ethylene glycol monomethyl ether was used instead of propylene glycol monomethyl ether acetate in Example-6.
An original printing plate was prepared in the same manner as above.

Comparative Example-14 Example-6 except that propylene glycol monomethyl ether acetate was replaced with propylene glycol monomethyl ether acetate.
An original printing plate was prepared in the same manner as above.

Next, when the printing original plates obtained in each of the above Examples and Comparative Examples were subjected to plate making using an electrophotographic engraving machine in a room at a temperature of 23°C and a relative humidity of 48%, the printing original plates of Examples 1 to 6 were Although a normal image was obtained in Comparative Examples 1-14, the plate surface did not have a sufficient amount of charge, and only a toner image with an extremely small amount of toner was obtained, and these thin toners were used in the next process. When removing the photoconductor layer in the non-image area with an alkaline solution, the photoconductor layer leaked out and a normal image could not be obtained.

In order to properly make the printing master plates of Comparative Examples 1 to 14, additional drying for about 1 hour was required in an oven whose internal temperature was set to io'c.

The alkaline solution used to remove the photoconductor layer in the non-image area was as follows.

◎ In the case of printing master plates of Examples 1 to 3 and Comparative Examples 1 to 7: Positive type P manufactured by Konica Corporation
S plate developer (alkaline solution) 7 times developer of "5DP-1" ■ In the case of printing original plates of Examples 4 to 6 and Comparative Examples 8 to 14... = -... manufactured by Chemco, Powerpl
ate (EAC-1) developer solution (alkaline solution) [
Effects of the Invention] In the present invention, the original printing plate coated with a photosensitive liquid has its original good photographic properties even if it is not dried to a near-absolute state like conventional printing original plates.

Therefore, the amount of heat and other energy required for drying can be reduced compared to conventional methods, and the present invention can omit the conventional post-drying process, thereby increasing productivity in continuous production. It is advantageous to be able to do so.

Second, the propylene glycol monomethyl ether acetate used in the present invention has low toxicity and no irritating odor, so it has extremely good workability when preparing printing plates.

Claims (1)

[Claims] In a printing original plate which has a photoconductor layer on a support and which produces a printing plate by removing the photoconductor layer in the non-image area after toner image formation, the photoconductor layer is coated with propylene glycol as a coating solvent. A printing original plate, characterized in that it is formed by coating on the support using a solvent containing monomethyl ether acetate.