Operation points of gravure printing in prepress c

Operating points of gravure printing in prepress control process

control before printing in order to make the printing process smooth, plate making, color matching, proofing and other work must be effectively controlled before formal printing. Plate making design in plate making, the original design needs to be modified according to the characteristics of gravure printing to make it more suitable for printing needs

in order to meet the needs of overprint, small lines and characters cannot be overprinted in multiple colors. There should be no small anti white words on the overprint pattern, and it should not be left blank on the overprint pattern and covered with other small characters. For the version with strict overprint requirements for portraits, the torsion mechanical properties of the intermediate materials of black, blue, red and yellow plates should not be separated from other color plates as far as possible. In order to meet the needs of printing, the bar code shall be arranged so that the line direction is consistent with the circumferential direction of the cylinder. The color should ensure the direction. If possible, the large field background color and the hierarchical pattern plate should be made separately, and the special plate should be used as far as possible. The two color jump areas of 80% and 5% must be fully considered for plate hanging, and the limit of gradient hanging time point should be more than 10%

ink blending ink blending mainly includes two aspects: on the one hand, it refers to the adjustment of ink printing adaptability, such as ink viscosity and concentration. The principle is to adjust the ink viscosity with diluent (solvent). Before printing, determine the ink viscosity according to the conditions of plate roller and machine table, and often add solvent according to the volatilization of solvent during printing to ensure that the ink viscosity remains unchanged as far as possible; When the ink is to be diluted, a diluent (ink blending oil) must be used

another aspect of ink blending refers to the blending of ink color. In this respect, the following points should be paid attention to: the standard light source (D65) should be used as the light source for observing the color. If there is no standard light source, it is better to build the scaffold and fastener in the sunny north window (1). When preparing spot color, primary ink should be selected for blending, so that the brightness and saturation of ink color can be guaranteed. Use as few ink colors as possible for color matching. The more colors, the greater the color matching error, and the greater the difficulty of re color matching. Proofing: when a set of printing plates is put into printing, a standard sample must be confirmed. Some manufacturers take the proofing draft of the plate making factory as the standard sample, and the sample cannot be matched at the time of final printing and delivery. Therefore, the printer must be used for proofing before printing, and it shall be used as the standard sample after being confirmed by the customer or relevant personnel

the printing of standard samples should be carried out under normal printing process conditions, so the following points should be paid attention to when proofing: select the most basic printing process conditions. The viscosity of ink should be as low as possible. The primary color ink should be added, and the contaminated ink that has been used for many times should be used for proofing as little as possible. Prohibit all non-standard operations in order to excessively pursue the effect during proofing, and reduce the cost of post-processing process; It also has excellent surface quality, such as increasing concentration and viscosity to increase hue, adjusting pressure and scraper to improve ink transfer rate, etc. Ink must be stirred evenly before use, especially spot color ink. The base note must be scraped accurately and recorded for reference. When proofing, try to achieve the normal printing speed. If conditions permit, after confirming the basic color of the sample, first print a certain number of products, and then take samples to confirm them as standard samples, which are sealed and stored as archives. After the standard sample is confirmed, 2 ~ 3M connected to it shall be cut as the equivalent standard sample, which shall be properly stored in a place without heat source and ultraviolet ray. In the future, the cut part shall be used as the printing sample during each printing