JPS5945157A - Prevention of offset of ink - Google Patents

Abstract

PURPOSE:To prevent the offset and blocking of ink by a method in which porous fine powder is spread on the surface of a printed medium after printing to absorb the solvent of ink and also to promote the gelling of resin, and the setting time of the ink is shortened and spaces are formed between sheets of paper. CONSTITUTION:Sheet of paper 1 is sent through a feeding cylinder 2, a feed board 3 and a swing grip 4 to an intermediate cylinder 5a, and a process ink of yellow color, for example, is supplied through a plate cylinder 6a to a blanket cylinder 7a. The ink is contacted with the paper 1 between the blanket cylinder 7a and an impression cylinder 8a for printing. By repeating the same processes thereafter, inks of red, blue and black colors, for example, are printed on the paper 1, and the paper 1 is directed to a paper discharge cylinder 9. The paper 1 is delivered on a belt conveyer 11 to a paper discharge roll 12 and piled up on a paper discharge pile 13, during which period porous fine powder is spread on the paper 1 from the spray nozzle 14 of a powder sprayer 10. Trouble such as offsetting and blocking of ink can thus be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing set-off of offset sheet-fed ink.

Offset sheet-fed inks generally contain resin, vegetable oil, solvent,
The offset sheet-fed ink (hereinafter referred to as "sheet-fed ink") has pigments as its main component, and when printed on paper, the solvent penetrates into the paper, which causes the resin dispersed in the solvent to spread onto the paper. The vegetable oil undergoes a process in which the unsaturated fatty acid ester in the vegetable oil is oxidized and polymerized, and then dried.

The printed paper is taken out one after another from the paper output section of the printing machine and stacked, but as the printing paper is pressed down by its own weight, the ink on the lower printing paper may stick to the back side of the printing paper above it (back side). Problems arose in which printing paper adhered to each other using ink as a binder (referred to as "blocking"). Conventional countermeasures have been to remove drainboards by inserting a drainboard between the sheets of paper, spraying starch powder, heating and drying the printed material, and irradiating it with ultraviolet or infrared rays, but these methods include: These drawbacks are a major obstacle to speeding up printing.

The drainboard removal method requires a great deal of labor and has the disadvantage that the printed surface loses its smoothness. The starch powder spray method is a method that prevents ink set-off by scattering starch powder to form gaps between the sheets of paper, and is sufficient when printing speeds are low, but when printing speeds are high, sufficient gaps are formed between the sheets. It has the disadvantage that set-off is more likely to occur because it cannot form. The heating drying method for printed matter involves heating and drying printed matter.
The problem is that cooling requires a huge amount of energy.

Ultraviolet irradiation method (% 1984-108479. 1984-7
2237゜1523o6) requires a special ultraviolet curable ink, which is 2 to 6 times more expensive than regular ink, and requires an expensive ultraviolet irradiation device, making it impractical. There is a problem. Infrared irradiation method (
%Kasho 55-55217) aims to be a non-powder product that does not require powder spray, but currently it is not possible to completely set the printing surface immediately after printing, and the amount of powder sprayed is reduced compared to conventional methods. I can only expect results. Also microwave, Regu light.

Electron beam irradiation methods also have ink and equipment costs.

There are many problems in terms of energy consumption, and it is not practical.

The present invention provides a new method that completely prevents ink set-off and blocking, and the gist of the method is to spray porous fine powder on the surface of the printed matter after printing, thereby removing the ink solvent from the porous fine powder. It absorbs and promotes gelation of the resin, thereby shortening the setting time of the ink and forming a gap between the sheets.

The porous fine powder used in the present invention is natural or synthetic zeolite, silica gel, alumina gel, and activated carbon, and the particle size and specific surface area of the porous powder are approximately in the following range, and the specific surface area is extremely large. Because it is large, its solvent adsorption capacity is also very large.

In particular, as shown in Figure 1, zeolite has a structure in which the internal voids are narrower than the pore diameter a, so the absorbed solvent is adsorbed to the walls and difficult to escape again. .

Further, such a fine powder can be sprayed onto the surface of printed matter using a powder spray device, for example, between a paper delivery cylinder and a paper delivery roll of a printing press. Further, the present invention does not require the use of any special ink, and can be applied to commonly used commercially available offset sheet-fed inks.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

An offset sheet-fed printing line is shown in FIG.

Paper IFi paper feed roll 2. The feeder board 5 is conveyed to the intermediate cylinder 5a by the swing grip 4, and the process ink, for example, yellow, is supplied to the blanket cylinder 7a via the eaves and one plate cylinder 6a'f. The ink and the paper 1 come into contact between the blanket cylinder 7a and the impression cylinder 8a, and printing is performed.

From now on, repeat the same operation, for example, Beni and Ai.

Black ink is printed on paper 1, printing is completed,
Is paper 1 the paper output cylinder? reach.

The paper 1 is then conveyed by a belt conveyor 11 to a paper delivery roll 12 and stacked on a paper delivery pile 13, during which time it is sprayed with fine porous powder by a powder sprayer 10.

The powder spray method will be explained with reference to FIG. paper 1
is placed on a belt conveyor 11 passed between a paper delivery cylinder 9 and a paper delivery roll 12, and a powder spray machine 1 is placed on the way.
The fine porous powder that has passed through the hose 16 is sprayed from the spray nozzle 14 by the spray nozzle 14.

As shown in the example, the offset sheet-fed ink sprayed with the porous powder is set in a very short time, so even if the paper is stacked immediately at the paper exit, there will be no set-off, blocking, etc. No problems will occur.

As described in detail above, the present invention has the following advantages over conventional methods and is industrially useful.

(1) Printing efficiency and printing quality can be improved because set-off and blocking, which are obstacles during high-speed printing, can be completely prevented.

(2) Significant costs such as equipment costs such as drying ovens, cooling equipment, and exhaust gas treatment equipment, maintenance costs, and operating costs are saved.

It should be noted that the method of the present invention is not only applicable to offset sheet-fed printed matter, but can also be applied to various printed matter as needed as a means for quickly drying ink after printing.

Hereinafter, the effects of the present invention will be explained with reference to Examples.

Example Commercially available offset sheet-fed process ink yellow, red.

Eye and ink colors were printed sequentially on coated paper (weight q o o 97 m2) using a commercially available printing machine, and after printing the four colors, a porous material made of fine powder was sprayed using a powder spray machine. As shown in Table 1, the setting was completed in 1/20 seconds to a3 seconds.

Notes to Table 1 (1) Zeolitem is a synthetic zeolite with a pore size of 3X.

(2) Zeolite) B is a synthetic zeolite with a pore size of 4X.

(3) Zeolite) O is a synthetic zeolite with a pore size of sX.

(4) Zeolite) D is a synthetic zeolite with a pore size of 1 ox.

(5) Zeolite E is Kliptylol zeolite from Futatsui.

(6) Zeolite Fld is mortenite from Kirikushi.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the relationship between the pore diameter and internal voids of zeolite, Fig. 2 shows the entire offset sheet-fed printing line, and Fig. 3 is a diagram explaining the fine powder spray method in the present invention. . Sub-agents 1) Meifuku agent Ryo Hagiwara -

Claims (1)

[Claims] A method for preventing ink set-off, which is characterized by scattering fine porous powder on the surface of the printed material after printing.