The abbreviation for the cardboard produced by the plate-making factory. The general board-making process is completed by the corrugated cardboard production line (referred to as the corrugated line). The board-making process: the base paper is installed on the base paper rack and enters the single-sided machine through the paper splicing machine. Corrugated paper is then framed with original paper on both sides to make cardboard. Platemaking is the general term for copying original manuscripts into printing plates. There are a series of plate making methods such as arranging lead type into movable type plates, using movable type plates to make paper molds and casting them into replica relief plates, taking pictures or electronic color separation to obtain negatives, and using the negatives to make relief plates, lithographs, and gravure plates. The most factors that affect the quality of printing plates in plate making include developer concentration, development temperature and development time, the circulation and stirring of the developer, and the degree of fatigue decline of the developer.

Printing and plate making process

Cutting

After the film (also known as film) is sent from the phototypesetting workshop to the plate making workshop, the first thing to do is to cut the blank of the film Partially cut out, that is, clipping. The correct operation method is to place the film face up on the viewing table. First, check the odd and even numbers of the version. If it is an odd-numbered version, cut off the blank part on the left side of the film; if there is a middle seam, try to cut as much as possible. It may be on the inside to prevent the imposition personnel from reprocessing; if it is an even-coded version, cut off the right side of the film. The above is the cutting method for black and white film. If it is a color film, you generally need to leave a registration mark on the top and bottom.

Imposition

Imposition is divided into book version and newspaper version. The 8-page newspaper version generally uses book version spelling. Common page numbers are 4, 8, 16, 24 and 32, and occasionally there are 48 or 64 pages. Usually when putting together, the large edition is first divided into several marked parts, such as A. B. C. D several pages, such as a 64-page newspaper page can be divided into A32, B32 or A, B, C, D each of 16 pages. (1) Regular imposition of newspaper pages follows the following rules: ① The sum of the edition numbers on the upper and lower sides on the left is equal to the sum of the edition numbers on the upper and lower sides on the right, and is equal to the maximum edition number plus 1. For example, in the case of version 32, the sum of the upper and lower version numbers on the left and right sides should be 33. ② The positions of the odd-numbered and even-numbered slots are fixed, and the small and large formats on the left and right sides are also fixed. For example, in the process of imposition of 32 editions, the four editions of 32, 25, 1, and 8 are the same as those of 24, 25, and 8. The four editions 17, 9, and 16 are put together on two large editions respectively, of which 32 and 24, 25 and 17, 1 and 9, and 8 and 16 are the same. (2) The imposition of 4-page newspaper pages generally follows the following rules: ① The number of pages is within 20, including 20 hours. The imposition is done in groups of 4 pages, and the two pages at the ends of the four pages are the same as the one in the middle. The versions are put together respectively, namely: 1, 4 and 2, 3, 5, 8 and 6, 7, 9, 12 and 10, 11, 13, 16 and 14, 15, 17, 20 and 18, 19. ② If the edition number is greater than 20, you can subtract an integer multiple of 20 from the edition number, and then proceed as in the first case. For example, 48 can be put together with 45, because 8 and 5 obtained by subtracting two 20s from 48 and 45 are put together. ③The odd-numbered and even-numbered editions have fixed positions. That is: 1, 3, 5, 7, 9... and 2, 4, 6, 8, 10... are the same.

Original hand

The imposition layout is obtained by folding the sample paper. The process of folding the sample paper is called folding the hand. According to the different folding methods of printing equipment and folding machines, the folding methods are also different. For example, the 8-page version can be divided into head-to-head and foot-to-foot, and the 4-page version can be divided into masthead-up and masthead-down. Generally speaking, for printing equipment with two triangular plates or using a folding machine, the folding hands are both hands, that is, for the 16-page version, the front 8 large and the back 8 small are set together; for the 24-page version, the front 8 are set together; The 16 big sets are put together and then the last 8 small sets are together; for the 32 version, the front 16 and the last 16 are in big sets and then the small sets are together.

Plate printing

Due to the strong timeliness of newspaper printing, the plate making workshop of newspaper printing plants generally advocates the "weak exposure" plate printing method in order to save time in the plate making process. , set the printing time to be shorter, and adjust the plate development conditions accordingly to produce a printing plate that meets the printing requirements. In addition, when printing, you also need to pay attention to the cleanliness of the glass of the printing machine and the suction condition of the vacuum pump.

Developing the plate

In order to adapt to the weak exposure printing conditions when developing the plate (developing), the ratio of the developer is generally higher than the concentration in the instruction manual.

Taking the developer as an example, the instructions require that the ratio of the original solution to water is 1:5~1:8, while "weak exposure" is generally prepared at a concentration of 1:4. After the printing plate is rinsed out, it is often dirty. There are usually two ways to deal with it. One is to rinse the printing plate again, but it is too time-consuming. The other method, which is also a better method, is to add a certain amount of it to the developer. Use a certain amount of washing powder to remove dirt by enhancing the molecular activity of the developing solution.

Revision

The most critical point when revising is to remove the film edges that should not be present on the printing plate. Traces of dirt repaired with a revision pen must also be wiped off promptly with a damp cloth to avoid dirt during printing. For scratches on the printing plate, you can use a fine brush dipped in a little dilute sulfuric acid to apply it to the scratched area.

Check the imposition quality

Layout inspection is the last process before the printing plate is put on the machine. If this process is not strictly controlled, it will bring great economic losses to the printing factory. . In addition to checking whether the text and pictures on the layout have broken pens, missing drawings, or blurring, the layout inspection also requires a detailed inspection of the layout of the layout. If it is a printing plate that is printed continuously, it is also necessary to check the deviation between the first and second printing of the four YMCK printing plates. Printing workshops mostly rely on visual inspection to check the quality of printing plates. However, due to the small contrast between the graphics and text on the printing plate and the blank parts, long-term inspection will cause fatigue, and some errors are difficult to detect. A better inspection method is to remove ink from the washed printing plate in time to increase the contrast of the printing plate to adapt to the observation habits of the human eye