Gravure printing machine registration system adjusting method

The wide application of plain laser paper (quantitative 100~250g/m2) and optical column transfer paper has become a modern packaging. The trend of printing . Because the aluminum layer on the surface of the plain laser paper and the light column transfer paper and its own micro-striped grating will have a reflective and colorful effect, it will interfere with the positioning of the printed electric eye, which greatly affects the printing registration.

In this paper, the author introduces a method for adjusting the gravure register registration system, which not only can effectively solve the above problems, but also does not need additional cost.

statement of problem

It is printed on a web gravure press using plain-faced laser paper. If the angle of illumination of the existing overprinting electric eye is used, the cursor cannot be grasped, so accurate positioning cannot be achieved.

This is because the characteristics of the laser paper determine the characteristics of the surface of the paper, which is a reflective paper surface, and the diffuse light is very strong at most angles on the paper surface. The overprinting electric eye of the gravure printing machine can only adjust the angle between 0° and 20°, which is relatively stable for the overprinting of ordinary white cardboard or gold and silver cardboard, but for laser paper, the angle of this interval will be The overprinting electric eye produces very strong reflected light on the reflective paper surface. As shown in Fig. 1, the cursor signal reading is unstable, the overprinting fluctuation is relatively large, and normal production cannot be achieved. In this case, the conventional practice is to leave a paper edge of about 14 mm wide on the side of the laser paper, and do not make the colorful effect of the surface of the laser paper, directly made of aluminum silver edge, used to print the overprint cursor, and this 14 mm wide The aluminum silver edge can only be used for the printing of the overprinting cursor, which invisibly increases the material consumption, thereby increasing the printing cost.

Solution development

In order to solve the above problems, and at the same time without additional cost, the author introduces an adjustment method, which not only makes the adjustment angle of the overprinting electric eye larger, but also avoids the angle of the reflected light, and obtains a relatively stable pulse signal to achieve accurate overprinting. . At the same time, by first printing the white ink and then printing the overprinting cursor, the paper edge of 14mm width is omitted, which saves paper and printing cost.

In order to realize this adjustment method, we have specially designed a device including a bracket, an adjustment block, a fastening screw and an electric eye fixing block to cooperate with the adjustment of the angle of the overprinting electric eye.

The schematic diagram of the independent unit structure of the gravure printing machine is shown in Fig. 2. The figure shows the angle of the printed electric eye during the normal printing process, and the general adjustment range is between 0° and 20°. Through a large number of angle adjustments, it is proved that the angle between the printed electric eye and the paper surface is appropriately increased. When the electric eye forms a 40° angle with the laser paper surface, the overprinting signal is relatively stable, but the angle adjustment range of the gravure printing machine's own overprinting adjustment device is only 20 °, so the overprint adjustment device needs to be modified. The modified device is shown in Figure 3. Adjust the tilt angle of the two holes with the overprinting electric eye to an angle of 40° to the vertical surface (the specific data depends on the overprinting condition of the different equipment, and the data is obtained in the test phase before processing adjustment device).

As shown in Figure 4, the mounting position of the printed electric eye is printed according to this angle. At the same time, the white ink is used to print the overprinting cursor, which can eliminate the extra silver offset of the laser printing, which greatly reduces the production cost, and can be tried by the peers in need.

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