JPH0635216B2 - Processing liquid for lithographic printing - Google Patents

Description

The present invention relates to an electrophotographic offset master, a processing solution used for printing a ps plate, that is, an etching solution and a fountain solution.

(Prior Art) An electrophotographic offset master first obtains a lipophilic image on a photosensitive layer formed by coating a photoconductive fine powder such as zinc oxide together with an electrically insulating resin on a support by an electrophotographic method.

Further, there are a method in which an image is directly formed on the master by a lipophilic writing instrument or type to form a printing plate, and a method in which an electrophotographic transfer method is used.

In these, the non-image area is converted from lipophilic to hydrophilic by an etching treatment to obtain a printing plate. In order to maintain hydrophilicity during printing, the treatment liquid is usually diluted several times and used as fountain solution.

Many processing solutions have been proposed so far. When they are classified by main component, they are divided into yellow blood salt system and non-yellow blood salt system.
The yellow blood salt system has been used for a long time. This is unstable with respect to heat and light, and has drawbacks such as deterioration of etching power and occurrence of precipitation even after natural aging. Therefore, many proposals have been attempted to improve these drawbacks. Further, with respect to the non-yellow blood salt system, efforts are continuing mainly to improve the etching power. However, they are still not enough. Further, in recent years, the range of application of printing by the electrophotographic offset master has expanded, and higher performance than ever has been required.

That is, printing stains do not occur on the non-image area and ink is sufficiently applied on the image area (= good inking property). To prevent stains such as fingerprints, it is made hydrophilic with a planographic printing treatment liquid immediately after plate making. Even after printing for several hours after processing, the highlights of thin lines and halftone dots do not fade and the ink can be applied sufficiently (= good ink receptivity after being left to dry), and normal printed matter can be obtained immediately after printing. That it can be obtained (= ink is applied quickly) and that it does not cause scumming even after printing a large number of sheets.
Even if the ink accidentally adheres to the non-image area and becomes dirty, it can be easily removed by idling the printing machine (excellent in removing ink adhered dirt), and hydrophilicity even after long-term use. However, it must have such characteristics that no crystal or dust is generated.

(Problems to be Solved by the Invention) However, when etching treatment is performed using a conventional treatment liquid and drying is performed, there is a drawback that ink receptivity to the image area is deteriorated. This defect becomes more remarkable when left for a long time (plate setting) after etching and drying.

As a method to prevent this, there is a method of weakening the etching power (dilution, reduction of the content of the main agent, etc.). In this case, deterioration of inking can be prevented, but stains on the non-image area occur during printing, causing scumming on the printed matter. Will end up.

Another method is to add a surfactant. In this case, it is possible to prevent the inking deterioration without causing scumming on the printed matter, but it becomes very easy to cause bubbles, and when used in an etching processor, etc., liquid leakage due to foaming may occur, and the suitability for manufacturing may be reduced. There are problems such as getting worse. There is a method of adding an antifoaming agent to eliminate bubbles, but when added until the appearance of the defoaming effect, liquid stability is deteriorated such as phase separation, and side effects such as printing stains are shown. Not practical.

The present invention solves the above-mentioned drawbacks and provides a processing solution for lithographic printing that does not cause scumming of printed matter.

A first object of the present invention is to provide a treatment liquid which has good ink receptivity and does not easily cause print stains under any conditions.

A second object of the present invention is to provide a treatment liquid that is capable of quickly applying ink and is excellent in removing stains adhering to ink.

A third object of the present invention is to provide a maintenance-free treatment liquid whose hydrophilicity does not change for a long time.

A fourth object of the present invention is to provide a processing liquid having excellent suitability for production of a lithographic print that does not cause foaming during use.

(Means for Solving the Problems) The object of the present invention is achieved by a lithographic printing treatment liquid containing a compound represented by the following general formula (I) and further containing yellow blood salt as a main agent. To be done.

General formula (I) In the formula, R _{1 to} R ₄ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl, alkenyl, aryl or aralkyl group having 1 to 7 carbon atoms. It preferably has 1 to 4 carbon atoms. Furthermore, when R _{1 to} R ₄ are substituted, the substituent is an amino group, an ammonio group,
It is selected from a hydroxyl group, an acyloxy group and an acylamino group.

The total number of carbon atoms of R _{1 to} R ₄ is 16 or less, particularly 4 to 12,
Is preferred. Furthermore, two or more of R _{1 to} R ₄ do not simultaneously represent hydrogen atoms. Further, two of R _{1 to} R ₄ may be bonded to each other to form a ring. The ring may optionally contain heteroatoms such as nitrogen, oxygen and / or sulfur atoms.

A Is a hydroxyl group or a monovalent acid residue, preferably Cl ，
Br , I , HSO_Four , HPO_Four Inorganic acids such as
IsRepresents an acid residue of an organic acid such as.

Examples of typical compounds of the present invention are shown below, but the present invention is not limited or limited by these.

(CH_Three)_Four N · OH  (CH_Three)_Four N ・ Cl  (CH_Three)_Four N ・ HSO_Four  (C_TwoH₅)_Four N · OH  (C_TwoH₅)_Four N ・ Cl   (CH_ThreeCH_TwoCH_Two)_Four N ・ Cl       (C_TwoH₅)_Three NH / Cl  These compounds can be used alone or in a mixture.
However, the amount used (total amount when mixed) is preferable.
0.001 to 5% by weight, more preferably 0.01 to 1% by weight
Is.

As the main agent for hydrophilization, yellow blood salt and phosphate can be used, and the red blood salt can be partially contained in the yellow blood salt, which is generated by oxidation of the yellow blood salt.

In addition to these, a pH adjusting agent and a pH buffering agent can be used in combination. They use the well-known inorganic acids, organic acids and salts thereof alone or as a mixture. For example, formic acid, acetic acid, butyric acid, valeric acid, lactic acid, tartaric acid, propionic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid, phthalic acid, citraconic acid, itaconic acid, fumaric acid, tricarballylic acid, glycolic acid , Propionic acid, thioglycolic acid, malic acid, citric acid, gluconic acid, pyruvic acid, glycolic acid, salicylic acid, adipic acid, hydroacrylic acid, glyceric acid, p-toluenesulfonic acid and their metal salts, organic amine salts And so on.

It is also preferable to add a chelating agent such as EDTA-2Na and a reducing agent such as sulfite, particularly when the main agent for hydrophilicity is yellow blood salt, in order to maintain the hydrophilicity and prevent precipitation.

Further, when the main ingredient is a phytate, it is desirable to further add a water-soluble cationic polymer and a low molecular weight electrolyte compound as disclosed in JP-A-60-23099 in order to prevent stains from occurring.

Further, as a wetting agent and a wetting agent, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, gum arabic, carboxymethyl cellulose, acrylic polymer, methanol, ethanol, iso- and normal propyl alcohol, triethanolamine and the like can be added.

Further, a preservative such as salicylic acid, phenol, butyl phenol parabenzoate, sodium dehydroacetate, and 4-isothiazolone-3-one compound can be added.

In addition, rust preventives such as sodium nitrite and dicyclohexylammonium nitrite can be added.

In applying the processing liquid for lithographic printing according to the present invention to a printing plate, it may be used in any processing machine of an etching processor conventionally used in this field.

Further, the characteristics can be fully utilized for hand etching and pre-etching for the purpose of preventing stains such as fingerprints.

Further, the processing liquid for lithographic printing can be used as a dampening water for an offset master or PS plate by diluting it with water.

Examples of the present invention will be shown below. However, this does not restrict the present invention.

Example 1 Potassium ferrocyanide 20.0 g Ammonium phosphate 60.0 g Diammonium citrate 30.0 g Sodium sulfite 6.0 g EDTA-2 sodium 0.4 g Tetraethylammonium chloride 2.0 g Water (total) 1000.0 g This formulation was used as an etching solution and further with water. A 7-fold dilution was used as fountain solution, and a master produced by Fuji Film ELP-, MarkII system was printed with Hamada Star 800 using ELP ink (ink, quick dry). We were able to print clearly from the print start to 10,000 sheets without any stains. Further, the 3000 plate treatment was tested for one month while replenishing the etching solution. As a result, the first edition and the last 3000
There was almost no difference in the quality of the printed matter of the plate, and no deterioration in hydrophilicity, ink receptivity, etc. was observed. Almost no crystals, debris, or precipitates were found in the etching equipment. Moreover, generation of bubbles was not observed during the treatment. Similarly, when the master that had been left for 2 days in the room after etching and drying was printed in the same manner (drying and leaving test), the infiltration of the highlight portions of thin lines and halftone dots was extremely good.

Comparative Example 1 Tests were conducted in the same manner except that tetraethylammonium chloride was excluded from the formulation of Example 1.
In the dry standing test, the ink tended to be difficult to get onto a part of the image.

Comparative Example 2 A test was conducted in the same manner as in Example 1 except that equimolar polyoxyethylene octylphenyl ether was used in place of tetraethylammonium chloride in Example 1. In the processing test using the etching device, a large amount of bubbles were generated and liquid leakage occurred.

Example 2 A test was conducted in the same manner as in Example 1 except that equimolar tetra-n-propyl hydroxide was used instead of tetraethylammonium chloride in Example 1. The result was as satisfactory as that of Example 1.

(Effects of the Invention) The treatment liquid of the present invention is excellent in production suitability, and a printed matter obtained by using the treatment liquid also has excellent performances in ink inking property, background stain, etc.

The compound of the general formula (I) contained in the lithographic printing treatment liquid of the present invention includes commercially available products, etc., can be taken in relatively easily, and the treatment liquid having excellent performance can be easily and economically obtained. Can be prepared as desired.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Oishi, 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fujisha Shin Film Co., Ltd. Within Film Co., Ltd. (72) Inventor, Eiji Sera, 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Sha Shin Film Co., Ltd. (56) Reference JP-A-58-215399

Claims (1)

[Claims] 1. Containing a compound represented by the following general formula (I)
And a yellow blood salt as a main ingredient.
Liquid for plate printing. General formula (I)Where R₁~ R_FourAre each independently a hydrogen atom or carbon
Substituted or unsubstituted alkyl or alkeny of formula 1 to 7
Represents a ru, aryl or aralkyl group, or R
₁~ R_FourTwo of them together optionally contain heteroatoms
It forms an optional ring. However, R₁~ R_FourOut of
No two or more of them simultaneously represent hydrogen atoms. further
R₁~ R_FourWhen the is substituted, the substituent is
Amino group, ammonio group, hydroxyl group, acyloxy group
It is selected from among a Si group and an acylamino group. A Represents a hydroxyl group or a monovalent acid residue.