Standardization and dataization of color printing operation

4 Standardization of the printing process

The standardization of the printing process is based on photocopying and plate making of previous processes. Only when these pre-processes are standardized, it is meaningful to adopt standardized measures in the printing process. As the printing of color newspapers cannot introduce printing quality control strips, this is unfavorable to the standardization of the printing process. Now it is discussed from the aspects of operational standardization and parameter normalization.

1) Standardized operation of printing process

1 Keep the printing equipment intact. Ensure that the various parts of the printing press can be operated flexibly, and the rubber rollers, blankets, gaskets, fountain solution, etc. can be adjusted and prepared properly. If it is color-changing printing, ink fountains and rubber rollers should be cleaned to prevent cross-coloring.

2 Materials should maintain a certain degree of stability. Paper, ink, printing plates, blankets, fountain solution, etc. should maintain stability in order to ensure the stability of printing quality. If there are conditions, the paper should be dedicated to color newspapers, and the ink should not change constantly in order to match the photographing parameters.

3 Establish a paper warehouse with the same temperature and humidity as the printing environment to keep the water content of the paper relatively fixed. If there is no special paper library, the paper can be placed in the printing press workshop for humidity conditioning treatment several days in advance. The web is placed vertically to prevent extrusion.

4 Before printing on the printing plate, we should carefully check the quality of the printing plate and test whether the lightness of C, M, Y, K four single-color printing plates is suitable for printing requirements. Align the positioning pin holes to ensure accurate overprinting.

5 to determine the correct printing color sequence, because the newspaper's printing color sequence is more complex, specifically discussed later.

6 According to the "three-three" system operating principle to stabilize and improve the printing quality.

Sanping:

Under the premise of suitable pressure, make the roller, water roller and ink roller parallel to each other. At the same time, the widths of the embossed tapes at both ends of the rollers and in the middle are determined. This is the basic condition for ensuring uniform printing pressure, uniform water supply and ink supply, and a prerequisite for ink-water balance.

Sanheng:

a. The printing pressure is constant: In the printing, there are many phenomena that look like the printing pressure problem, but should analyze carefully before dealing with, can't adjust the pressure between the rollers arbitrarily.

b. The constant speed of the printing press: newspapers use a web of paper with a one-time feed printing, in addition to changing the paper should be maintained at a constant speed printing, which is conducive to controlling the ink balance.

c. The constant temperature and humidity in the workshop: The indoor temperature and humidity should be constant, so as to prevent changes in the printability of printing equipment such as ink and paper due to temperature and humidity changes.

Sanqin:

a. During the printing process, look at the proofs, observe the situation of registering, paper tension, dot change, and ink balance at any time, and find problems in time.

b. Clean water bucket, ink fountain, water roller and ink roller frequently to keep them clean and free of debris.

c. Wash the blanket cylinder frequently to maintain good image transfer performance.

7 The print shop should use daylight-type light sources to see samples to ensure the authenticity of color reproduction.

8 When printing, refer to the standard ink color adjustment and place Y, M, C, K four-color field bars in the newspaper head position.

The following spelled out the colored headlines and characters of various newspapers, and measured the density of solid blocks with a density meter at the time of printing. When the density of solid blocks reached the standards stipulated by the association, the ink colors of the following newspaper titles and texts also reached the standards accordingly. .

9 The ink supply during the printing process should be uniform, and the amount of ink supplied should be adjusted against the proofs and newspapers.

10 After the production is completed, the plate should be unloaded, and the plate cylinder, blanket cylinder, paper feed roller, operation table, machine surface, etc. should be cleaned, and the maintenance and repair of the machine should be observed.

2) The main parameters of the printing process

1 The temperature and humidity of the printing shop are constant, generally requiring a temperature of 23 °C ± 3 °C and a humidity of 50% ± 5%.

2 Maintain the ink balance, and the pH of the fountain solution is controlled within the specified range. The concentration can be determined by the following factors:

越 The thicker the ink layer thickness, the corresponding increase in concentration;

环境 The temperature of the production workshop is high and the concentration increases accordingly;

纸张 Poor paper properties, can increase the concentration;

衬垫 The gasket is hard and the pressure is large enough to increase the concentration;

需 Full version and solid plate need to increase the concentration, and the cable version can reduce the concentration accordingly.

3 Color registration requires that the image does not leak edge, overprint error is less than 0.5mm.

4 Ink color is based on the headline and headings larger than the small special number. The density is 0.95-1.3.

5 The ink color of the printing format is uniform, and the average density of the commonly used Xiaowu Song-style "" is based on the average density, and the density is 0.16 to 0.20.

6 The outlets are clear and the outlets are accurately angled, with no moire, no ghosting, and no distortion. (Author: Cao Han autumn)