Gravure plastic film quality control 2

For overprinting needs, such as small lines and texts cannot use multi-color overprinting, the pattern of color registration should not have small anti-white characters, and should not be left blank on the color registration pattern, and other small words should be put on. Yan version, black, blue, red, yellow version as far as possible between the other color version. For printing needs, the bar code should be arranged in such a way that the line direction is consistent with that of the cylinder. In terms of color guarantee, if there are conditions, it is best to separate the plate from the ground and color patterns, and use the special version as much as possible. Hanging screen version must fully consider 80% and 5% of these two color jump areas, and the limit of the screen points when the gradient is suspended is more than 10%.
2 Ink adjustment The adjustment of printing ink suitability, such as ink viscosity, concentration, the principle is to adjust the viscosity of the ink with diluent (solvent) adjustment, according to the situation of the roller and the machine to determine the ink viscosity before printing, in the printing process The solvent is often added according to solvent volatilization, but not excessive, as much as possible to ensure that the ink viscosity is unchanged; ink to talk about, you must use diluting agent (dipping oil), avoid diluting with solvents.
Ink color deployment. In this regard, the following points need attention: Observe the color of the light source as much as possible using the standard light source (D65), if there is no standard light source, it is better to have a sunny north direction. When preparing spot colors, primary color inks should be used for deployment. The primary color inks referred to here are the inks directly produced by the ink factory. The brightness and saturation of the ink color can be guaranteed. Color matching is performed with as few ink colors as possible. The more colors, the greater the color matching error and the greater the difficulty of rematching.
3. Proofing When a set of plates is printed, a standard proof must be confirmed. Some manufacturers take the sample draft of the plate making factory as a standard sample, and they cannot be sampled at the time of final delivery. Therefore, the printing machine must be used for proofing before printing, and the customer or the relevant person will confirm it as a standard sample. The printing of the standard sample should be carried out under the normal printing process conditions, otherwise it will be very difficult to follow the sample after printing. Therefore, the following points should be noted when proofing:
1 process conditions selected the most basic printing process conditions.
2 ink viscosity as low as possible.
3 The original color ink should be sampled after adding a certain amount of diluting agent. Use the contaminated ink that has been used many times for proofing.
4 Absolutely prohibit all non-standard operations that are done in order to over-pursue the effect when proofing, such as increasing the concentration and viscosity to increase the hue, adjusting the pressure, scraper to increase the ink transfer rate and so on.
5 Ink must be mixed before use, especially spot color inks.
6 Spot inks that are self-provisioned must be accurately recorded and recorded for future reference.
7 Try to reach the normal printing speed when proofing.
8 If conditions permit, after confirming the basic color of the sample, first print a certain amount of product (such as a roll of film), then sample and confirm it as a standard sample, and keep it as a file.
9 After confirming the standard sample, the connected 2~3m should be taken as the equivalent standard sample, and it should be properly stored in a place with no heat source or ultraviolet light, and the cut part of each print should be used as a sample after printing.
4. Common troubleshooting 1 dirty version: In the plastic gravure, the non-printing surface of the roller is often glued with a layer of resin (entrained pigment in the resin), and it is transferred to the substrate and is stained like a sheet. Or appear linear dirt, this is a dirty version. In addition to the hardness of the blade, the blade pressure, the blade contact angle, and the quality of the plate cylinder, the resulting dirty plate phenomenon is also related to the viscosity of the ink. (to be continued)