SU719895A1 - Method of automatically controlling the wetting of offset forms - Google Patents

Description

This invention relates to methods for automatically regulating the process of offset offset printing. A known method of automatically regulating the process of moistening the osse net of forms, consisting in applying an imprint to an offset form, measuring the optical density of an imprint and changing the supply of the moisturizing solution depending on the measurement results l. The disadvantage of this method is the low efficiency of the drying process. The aim of the invention is to increase the effectiveness (}) of the efficiency of the wetting process. The goal is achieved by the fact that an additional impression is simultaneously applied to the aerial form and its optical density is measured, and the change in the supply of the moisturizing solution is made in accordance with the extreme value of the difference in the density of the impressions. FIG. 1 shows a block diagram of the device, an explanation of the method; in fig. 2 - dependences of the optical densities D and Dg on the thickness of the moisture layer. for two prints with different optical densities; in fig. 3 - difference D - Dg which has a distinct extreme character. The device contains the brightness of 1 and 2 prints, photo cells 3 and 4, blocks 5 and 6 of the converters, subtraction unit 7, amplifier 8, extreme regulator 9, actuator 1O, offset form 11. The device operates as follows. On the base form 11, two labels are distinguished by their raster densities. The brightness of the impressions 1 and 2 of these labels by the photocells 3 and 4 are converted into blocks 5 and into optical densities, the values of which are subtracted from each other in block 7 and fed to amplifier 8, from where they enter B extremum pulse / tor 9,) performed / gygy. Mechanism 10,

Claims (1)

Claim A method for automatically regulating the wetting process of offset forms, especially in applying a print to an offset form, measuring the optical density of the print and changing the flow of the moisturizing solution depending on the result (About ⁴ measurement results, which differs in that, with In order to increase the efficiency of the humidification process, an additional impression is applied to the offset form at the same time as the first one, and its optical density is measured, and the supply of the moisturizing solution is changed in accordance with the extreme value spine density prints.