JPS6145555B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lithographic printing method that does not require desensitization treatment. In the general planographic printing method, a desensitizing liquid is applied to the plate surface of a planographic printing original plate having a lipophilic image to make the non-image area hydrophilic, and then water is supplied, and then lipophilic printing ink is supplied. This is done by applying ink only to the image area and transferring it to the printing paper using a roll. However, it is troublesome to make the non-image areas of the original plate hydrophilic each time printing is performed. Many etching processors that mechanically desensitize (etch) have also been devised. However, a printing apparatus that requires such an etching processor has a complicated mechanism and is expensive. Therefore, if an etching processor is not required and the desensitizing step can be omitted, it can be said to be a useful printing method that can simplify the apparatus. Therefore, we omitted the process of desensitizing the original plate and supplied water to the original plate.
A method has also been proposed in which lithographic printing is performed by simultaneously supplying a lipophilic ink and a desensitizing liquid.
However, in this method, for example, ferrocyan compounds or ferricyan compounds, which are known as desensitizing agents with excellent desensitizing ability, and phosphates, hydrophilic resins, and organic acids, which are expected to have a synergistic effect when used in combination with these compounds, are used. Alternatively, even if a desensitizing liquid containing an inorganic acid as a main component is used, there is a drawback that background stains and gear stains occur on the original plate or printed matter after a small amount of printing. It is thought that such defects occur because the ferrocyan compound or ferrocyan compound is extremely unstable to heat and light, and during use or storage, it becomes colored or precipitates, resulting in a decrease in desensitizing power. Phosphates, hydrophilic resins, etc. do not have such drawbacks, but
Since it has a weak desensitizing power, it is impossible to print a large amount even if it is used alone as a desensitizing agent. The present invention does not require an etching processor, and therefore, by omitting the desensitization step,
The present invention provides a useful lithographic printing method that simplifies the printing process and equipment. The present invention also improves the drawbacks of the lithographic printing method, which does not require a desensitizing process. Specifically, the present invention eliminates the drawbacks caused by the use of conventional desensitizing agents, and further simplifies the printing process, eliminating the need for a desensitizing process. This method provides a reliable lithographic printing method. Such a method involves applying water once to the surface of the lithographic printing original plate without desensitizing it, and then applying water to the surface without using water so that the hydroxyl group at the 1-position and/or 4-position becomes a metal ion. This method is characterized in that lithographic printing is carried out by simultaneously supplying an aqueous solution containing a desensitizing agent selected from the group of myo-inositol hexaphosphates, which has been inactivated so as not to react, and a printing ink. The basic difference between the printing method of the present invention and conventional printing methods is that a desensitization step is not required. In order to achieve this objective, it is necessary to use a specific type of insensitizing liquid that is supplied simultaneously with the printing ink.
Furthermore, the desensitizing agent used in the desensitizing solution must have a fast desensitization rate and high hydrophilicity. Furthermore, once formed, the desensitized film must be strong and insoluble in acidic solutions. The specific myo-inositol hexaphosphate derivative used in the present invention is a highly hydrophilic compound containing many OH groups. The reaction rate of the chelate formed between 2, 6 or 5, 3 is high, and the chelate after the reaction is extremely stable, so it can be applied to the method of the present invention. On the other hand, the conventionally commonly used sodium ferrocyanide has low hydrophilicity, and the hydrophilicity of the chelate obtained by the reaction is also low, so it is not suitable for the method of the present invention. This fact is reflected in the desensitizing agent used in the present invention and the conventional desensitizing agent (sodium ferrocyanide), as shown in the table below.
This can also be seen from the physical properties of the chelate compound formed.

[Table] The desensitizing agent used in the present invention is a desensitizer that binds the hydroxyl group at the 1-position and/or 4-position of the myo-inositol hexaphosphate represented by the following formula to a suitable metal, for example, so as not to react with metal ions. These are deactivated by atoms or substituents (hereinafter referred to as myo-inositol hexaphosphate derivatives). Such metal atoms or substitutions Examples of the group include divalent metal atoms such as Ba, Mg, and Ca, and examples of the substituent include alkyl, alkylhydroxy, alkylcarboxy, alkylamido, alkylamino, amino acid, aminocarboxylic acid glycol, and composite groups thereof. These myo-inositol hexaphosphate derivatives can be easily obtained by known methods. Specific examples include myo-inositol 2,3,5,6-orthophosphoric acid 1,
Barium 4-orthophosphate; Myo-inositol 2,3,4,5,6-orthophosphate Magnesium 1-orthophosphate; Myo-inositol 2,3,
4,5,6-orthophosphate 1-calcium orthophosphate; myo-inositol 2,3-orthophosphate 4,5,6-orthophosphate sodium magnesium 1-phosphate, myo-inositol 2,3,4-orthophosphate 5, Potassium 6-orthophosphate 1-Iron phosphate, Myo-inositol 2,6-orthophosphate 3,5-Sodium orthophosphate 1-Magnesium phosphate 4-Calcium phosphate; Myo-inositol 2,3,5,6-Orthophosphate 1 ,4-orthophosphoric acid methyl ester; myo-inositol 3,5
-orthophosphoric acid 2,6-sodium orthophosphate 1,
4-orthophosphate acetoxy ester; myo-inositol 2,5-orthophosphate 3,6-orthophosphate potassium 1,4-orthophosphate methylcarboxyester; myo-inositol 3,6-orthophosphate 2,5-orthophosphate sodium 1 , 4-orthophosphoric acid glycol ester; myo-inositol 1,2,3,5,6-orthophosphoric acid 4-phosphoric acid methyl ester; myo-inositol 1,2,
Cobalt 4-phosphate 3,5,6-orthophosphate;
Myo-inositol 2,3,4,5,6-orthophosphate 1-phosphate ethyl dimethylaminoester; myo-inositol 2,3,5,6-orthophosphate 1-barium orthophosphate 4-calcium orthophosphate; myo-inositol 2, 3, 5,
6-orthophosphate 1-calcium orthophosphate 4
-Orthophosphoric acid methyl ester and the like.
Among them, preferable ones include not only the four hydroxyl groups of phosphoric acid at the 1-position and 4-position, but also the 2-1, 3-1, and 5-hydroxyl groups.
Those in which two or more hydroxyl groups in the -1 and 6-1 positions are also inactivated, such as a myoinositol hexaphosphate 1,4-calcium salt, b myoinositol hexaphosphate 1,4 −
Magnesium salt 2-1,3-1,5-1 sodium salt, c myoinositol hexaphosphate 1-magnesium 4-calcium salt, d myoinositol hexaphosphate 1-barium 4-calcium salt, e mi Oinositol hexaphosphate 1,4-glycerin ester, f
Myo-inositol hexaphosphate 1,4
- polyethylene glycol ester, g myo-inositol hexaphosphate 1,4-glutamic acid ester, h myo-inositol hexaphosphate 1,4-arginic acid ester, i
Myo-inositol hexaphosphate 1,4
- Glutamate glycerol ester, j myoinositol hexaphosphate 1,4-ethylenediaminetetraacetic acid ester, k myoinositol hexaphosphate 1,4-methyl ester, l myoinositol hexaphosphate 1,4-hydroxyethyl ester, m myo-inositol hexaphosphate 1,4-methylcarboxylic acid ester, n myo-inositol hexaphosphate 1,4-acetamido ester, o myo-inositol hexaphosphate 1,4-glycerin 2-1 ,3-1,5-1 sodium salt, p-myoinositol hexaphosphate 1,4-calcium 2-1,3-1,5-
1,6-1 glycerin ester and the like. The desensitizing agent used in the present invention can be used in the form of an aqueous solution in combination with printing ink to form a strong hydrophilic film on the non-image areas of the original plate, thereby improving printing durability.
Note that a wetting agent such as glycerin, propylene glycol, isopropyl alcohol, etc., a PH regulator such as malonic acid, citric acid, tartaric acid, adipic acid, caustic soda, diammonium phosphate, etc. can be added to this aqueous solution. The lithographic printing original plate used in the present invention has a photosensitive layer in which inorganic photoconductive particles such as zinc oxide particles are dispersed in a resin binder, and this is used to form a lipophilic image by electrophotography. An electrophotographic original plate is equipped with an image-receiving layer in which inorganic pigments such as titanium oxide are dispersed in a resin binder, and a lipophilic image is formed by writing or typing directly on this layer with oil-based ink. Either a plate original plate or a PS original plate in which a photocurable photosensitive layer is provided on a grained aluminum plate and a lipophilic image is formed by utilizing the difference in solubility between exposed and non-exposed areas of the photosensitive layer. good. Examples are shown below. Examples 1 to 12 Printing was performed using a typewriter on Master A, in which a lipophilic toner image was formed using an electrophotographic method on a commercially available electrophotographic original plate, or on commercially available direct drawing paper, and further drawing was performed using a ballpoint pen and a felt-tip pen respectively coated with oil-based ink. The master B on which the lipophilic image has been formed is attached to the master cylinder 2 of the printing press shown in the attached figure. The water 5 is pumped by a pumping roller 6 to a water dampening roller (eg Molton) 7. A water dampening roller 7 contacts the master 1 on the master cylinder 2, so that the master 1 is evenly moistened with water. Next, a lipophilic printing ink 11 and a desensitizing liquid 12 as described above are applied to the master print. printing ink 11
The desensitizing liquid 12 is kneaded by the supply roller 8 and sent to the roller 14. That is, a printing roller 1 that attaches ink and desensitizing liquid to the master.
4 comes into contact with the master 1, and thus the non-image areas of the print become more hydrophilic than the desensitizing liquid 12, and the ink 11 adheres to the image areas. Next, the ink in the image area of the master 1 is transferred to the blanket 3, and this transferred ink is further transferred and printed onto the printing paper 13 fed from the cylinder 4. Sample desensitizing liquid Example 1 1% aqueous solution of compound a 〃 2 2% aqueous solution of compound b 〃 3 50 g of glycerin is added to the sample of Example 1. 〃 4 5% aqueous solution of compound e 〃 5 5% aqueous solution of compound g 〃 6 Add NaOH to the sample of Example 4 to adjust pH=
Set it to 5.0. 〃 7 1% aqueous solution of compound i 〃 8 1% aqueous solution of compound k 〃 9 2% aqueous solution of compound l 〃 10 2% aqueous solution of compound m 〃 11 2% aqueous solution of compound o 〃 12 Malonic acid was added to the sample of Example 7 Add 10g and adjust the pH to 4.0 with KOH. Comparative Example 1 Dissolve 10 g of sodium ferrocyanide and diammonium phosphate in 1000 ml of water, and adjust the pH to 5.0 with citric acid. Comparative example 2 20 g of potassium ferrocyanide and 3 phosphoric acid
Dissolve 60g of soda in 1000ml of water and adjust the pH to 4.5 with tartaric acid. Comparative Example 3 20g of sodium ferricyanide, 40g of 1ammonium phosphate, 20g of diammonium phosphate
Dissolve g, 40 g of glycerin, and 1 g of sodium dehydroacetate in 1000 ml of water and adjust the pH to 5.0 with malonic acid. The above printing results are as follows.

[Table] Birth occurrence

[Brief explanation of the drawing]

The figure is a schematic diagram of a lithographic printing machine used in Examples. 1: Master (lithography), 2: Master cylinder, 3: Blanket, 4: Paper cylinder,
5: water, 6: pumping roller, 7: water dampening roller, 8: ink and desensitizing liquid supply roller,
9: Ink supply roller, 10: Desensitizing liquid supply roller, 11: Printing ink, 12: Desensitizing liquid, 13: Printing paper, 14: Roller with ink and desensitizing liquid.

Claims (1)

[Claims] 1. After once applying water to the surface of the lithographic printing original plate without desensitizing it, the surface is treated without using water to prevent the 1- and/or 4-position hydroxyl groups from reacting with metal ions. A lithographic printing method comprising simultaneously supplying an aqueous solution containing a desensitizing agent selected from the group of activated myo-inositol hexaphosphates and a printing ink to perform lithographic printing.