SU984885A1 - Offset printing method - Google Patents

Description

The design relates to printing, in particular, to offset printing technology.

The known method of offset printing includes moistening the spacing elements of a printing form with a moistening solution containing an optically bleaching agent, applying ink to the printing areas of the printing form and transferring the moistening solution and the ink from the printing form to the seals. Roll paper material 1.

 In the well-known textbook, due to the presence of the S wetting solution of an optically separated bleach of the substance, the lightness of the contrast between the print space and the element of the colorful image increases. You can improve the quality of paper bleaching in print gaps by increasing the supply of dampening solution to the printing form. However, such an increase entails the occurrence of paper deformation due to the large and long-lasting moistening of the print.

The purpose of the invention is to improve the print quality by increasing the lightness of the contrast of the image of the produced prints, excluding their boxing (i.e.

This goal is achieved by the fact that according to the method of offset printing, which includes moistening the blanks of the printing form with a moisturizing solution containing a plastic bleach, applying paint. onto the printing areas of the printing form and transferring the moisturizing solution and ink from the printing plate to the printing paper material, after transferring the wetted solution and ink, the printed material is passed through a magnetic field across the direction of the magnetic lines of force.

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An offset printing method is carried out on offset No. 1A paper weighing 80 g / m and a moisture content of 5.5% using an offset form containing 2Q text on 20% of the area. An optically bleaching agent is introduced into the moistening solution in the amount of 1%, which, together with the moistening solution, is transferred from the whitespace of the printing form to the material to be printed.

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The resulting prints are passed through a magnetic field of 1200 Oe at a speed of 1.2 m / s across the direction of the magnetic field lines.

Missed through a magnetic field

30 prints, gathered in a small foot.

placed in a hygrostat chamber that communicates through the air outlet. The humidifying air humidity, which is directed at a constant speed into the chamber, is maintained at 35% at. Both before being placed in the chamber, and after the stipulated residence time, the paper determines the moisture content according to GOST 13525.19-71. The control group of impressions is not passed through a magnetic field.

The results of the determination of humidity are tabulated.

As follows from the table, desorption of moisture from paper in the initial phase is more active under the condition that the paper was passed through a magnetic field.

The effect of the magnetic field on the water system is accompanied by both a decrease in the hydration of ions, and the destruction to some extent of the quasicry of the water's structure, which contributes to an increase in the rate of migration of moisture in paper and evaporation. At the same time, the hydration (wetting) of paper fibers in capillaries located somewhat deeper than the surface of the impression layer is reduced. As a result, a reduction in the moisture transfer time occurring at the initial and most intense desorption phase is observed, which, as is known, coincides with the almost complete shrinkage of paper to the original size.

The use of the proposed offset printing method, in comparison with the known method, reduces the time required for the shrinking process of the paper to almost its original size, which is technologically advantageous, as it allows increasing the supply of the moistening solution with optical bleach to the printing form and improve print quality.

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Claims (1)

Invention Formula The method of offset printing, which includes moistening the spacers of the printing plate 40 with a moisturizing solution containing an optically bleaching agent, applying ink to the printing areas of the printing plate and transferring the moisture to the solution and ink 5 sec. 0 This is due to the fact that, in order to improve print quality, after transferring the moistening solution and ink, the material being printed is passed through a magnetic field across the direction of the magnetic lines of force. Sources of information taken into account in the examination. 1, USSR Author's Certificate No. 802093, cl. In 41 M 1/06, 1974 (prototype).