Precautions and control management methods for color difference failures
1. Pre-printing stage management method
(1) The printing engineer must read the production process sheet carefully to see clearly, The quality requirements of the printed workmanship on the printed color, while clearly printing the color, The color standard is digital proofing or inkjet proofing, spot color, Pantone chromatography is still with the customer to sample, be aware of.
(2) When arranging a print production plan, the same batch of products should be kept as safe as possible,The same people are on the same stamping machine, especially the bulk new ones. As far as possible, products are arranged for printing in a certain group of people in the day shift. Due to the erroneous production arrangement, the color difference may be caused.
(3) Clear tinplate and ink brand, specification, size, oil,The thin ink should be adjusted well, and the printing should be arranged according to the characteristics of the printed product Color sequence, then correct the plate.
(4) Ensure that the printing station looks clean and does not disturb the color.And sample inspection under standard light source
Signing test stage management method
(1) Before the official printing production, it is necessary to find out the timing of signing. positive In the printing process, the ink contained in the ink roller is 15% to 26%. When printing is started, the water content in the ink is the lower limit. Deep, if at this time the sample, such as a large number of printing product color and sample comparison It is shallow; otherwise when the water content in the ink is the upper limit, the printing ink color Relatively shallow, if at this time the sample is signed, etc. The ratio is deeper. Therefore, it is necessary to identify the timing of the sample, and at the same time to judge a large number of the color change trend after production.
(2) For new products, related personnel must go to the printing site and print Iron Captain, Technical Supervisor, Quality Supervisor, Business Executive, Customer Representative After the parties sign and confirm the samples together, they can print in large quantities.
(3) Proofreading correct operation: Adjustment overprinting → School edition → Correction
Ink → Ink → Approved → Official Printing
3. Normal printing process management method
(1) Ensure proper printing pressure, that is to ensure the integrity of outlets Transfer, and do not paste the previous mention, with the smallest printing pressure.
(2) Correctly understand the balance of ink and water and follow it in formal printing production.When the quantity of fountain solution is observed, make sure the water supply of the water roller is normal.At the same time, under the state of ink and ink balance, it is necessary to continuously monitor the color of printed products with a density meter.Ink density values to establish the data management of the ink balance on the printer.
(3) Formal printing, the captain of the printing iron shall strictly control all process parameters The number to ensure the color of the batch product is consistent.
(4) When a large quantity of printing is applied, it is found that the printing plate is scratched, and it should be more timely.Change, prevent flower version.
(5) When printing double-sided products, we must pay attention to checking the positive and negative sides.Whether the color of the ink is the same or not and prevent the formation of positive and negative chromatic aberration.
(6) When using quality control, use the same wet density test method Control. Measured on-site density values of products to be signed by customers Compared with Table 2, the color difference value △E a*b* value was measured against Table 3.
The national standard stipulates that the on-site density tolerances for the different printed sheets of the same batch of products are:
Yellow (Y) Small ≤ 0.10; Blue (C), Magenta (M) ≤ 0.15; Black (K) ≤ 0.20.
(7) There are conditional printers that can be introduced into the online inspection system. All prints are checked online, using multiple measuring heads Line inspection, connecting color, ink, grease, water stains, scratches, etc. Line detection, the test result and the pre-stored standard number of proofs Compare the values. Quantitatively Detecting the Color of tins Products Produces Color Difference and printing accuracy, using objective test data to replace manual operation In addition to human factors of instability monitor the color difference.
In short, there are many factors that cause the chromatism of Indian iron products. We must make a comprehensive analysis based on specific conditions, targeting different products. Effectively prevent and standardize printing processes during prepress production Form an efficient color management system and color difference monitoring, so that it can be stabilized Fix the color of iron products to reduce the formation of color different