What does the plate-making factory mainly do?

The abbreviation of paperboard made by plate-making factory, the production process of general paperboard is completed by corrugated board production line (referred to as tile line). Paperboard making process: the base paper is installed on the base paper rack, enters the single-sided machine through the paper feeder to make corrugated paper, and then sticks the base paper on both sides to make cardboard. Plate-making is the general term for copying the manuscript to the printing plate. There are a series of plate-making methods, such as arranging the type into movable type plates, casting the movable type plates into paper-based cast-in-place replica relief plates, obtaining the negative plates through photography or electronic color separation, and drying the negative plates to make relief plates, lithographs and intaglios. In plate making, the factors that affect the quality of printing plate are the most, including developer concentration, developing temperature and time, circulating stirring of developer, fatigue decay degree of developer and so on.

Printing plate-making process

thin slice

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 off the blank part of the film, that is, cut the film. The correct operation method is to put the film face up on the stage, first look at the parity of the version number, if it is an odd code version, cut off the blank part on the left side of the film; If there is a middle seam, try to cut it on the inside to avoid re-processing by the imposition staff; If it is an even size version, cut off the right side of the film. The above is the cutting method of black and white film. If it is a color film, it is generally necessary to leave alignment marks on the top and bottom.

Make up/make up/make up/make up/make up/configure/make up/make up (a bed)

Imposition is divided into book edition and newspaper edition. 8. Generally, the printed version uses the spelling of the book version. Common versions are 4, 8, 16, 24, 32, and occasionally 48, 64. Usually in imposition, the number of large editions is divided into marked parts, such as A.B.C.D For example, a 64-page newspaper edition can be divided into A32, B32 or 16 editions of A, B, C and D respectively. (1) The regular imposition of newspaper sections follows the following rules: ① The sum of the upper and lower left edition numbers is equal to the sum of the upper and lower right edition numbers, which is equal to the maximum edition number plus 1. As 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 version and the even-numbered version are fixed, and the positions of the left and right small versions and the large version are also fixed. For example, in the process of imposition of the 32nd edition, the four editions of 32, 25, 1 8 and the four editions of 24, 17, 9 and 16 are placed on two large editions respectively, of which the imposition of 32 and 24, (2)4 newspaper editions generally follows the following rules: ① The edition number is less than 20. (2) If the version number is greater than 20, you can subtract the version number by an integer multiple of 20, and then use the method in the first case. For example, 48 can be put together with 45, because 8 and 5 are put together after subtracting two twenties from 48 and 45 respectively. ③ The odd and even versions are fixed. That is, 1, 3, 5, 7, 9… is the same as 2, 4, 6, 8, 10….

Put your hands together

Imposition is obtained by folding proofs, and the process of folding proofs is called folding hands. According to the different folding methods of printing equipment and folding machine, the folding methods are also different. For example, version 8 has a head-to-head, foot-to-foot distinction, and version 4 has a head-up and a bow. Generally speaking, for two triangular printing devices or using a folding machine, the folded hands are both two hands, that is, for the 16 version, the first eight bits and the last eight bits are nested; For version 24, put the first 16 together, and then put it together with the last eight small collections; For version 32, cover the front 16 and the back 16 separately, and then cover them together.

Flat combustion

Because of the strong timeliness of newspaper printing, the plate-making workshop of newspaper printing factory generally advocates the "weak exposure" printing mode, in order to save time in the plate-making process, set the printing time shorter, and adjust the printing conditions accordingly, so as to produce plates that meet the printing requirements. In addition, attention should be paid to the cleanliness of printer glass and the suction of vacuum pump when printing.

Impact products

In order to meet the printing conditions of weak exposure when printing (developing), the ratio of developer is generally higher than that in the specification. Taking developer as an example, the specification requires that the ratio of stock solution to water is 1: 5 ~ 1: 8, while "weak exposure" is generally prepared at the concentration of 1: 4. After the printing plate is washed out, it is often dirty. There are usually two ways to deal with it. One is to reprint the printing plate, but it takes too much time; Another method, which is also a better method, is to add a certain amount of washing powder to the developer to remove dirt by enhancing the molecular activity of the plate washing solution.

polish

The most important point of revision is to remove unnecessary film edge marks on the printing plate. Traces repaired with a revised pen must also be wiped off with a wet cloth in time to avoid getting dirty when printing. For the scratches on the printing plate, you can dip a little dilute sulfuric acid with a fine brush and apply it to the scratches.

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 greater economic losses to the printing plant. In addition to checking whether the words and pictures in the layout are damaged, less drawn and weak, we should also check the layout in detail. If it is a continuous drying plate, it is necessary to test the deviation between the first drying and the second drying of YMCK four plates. Printing workshops mostly rely on visual inspection of printing plate quality, but due to the small contrast between printing plate graphics and blank parts, long-term inspection will lead to fatigue, and some errors are not easy to detect. A better inspection method is to raise the washed printing plate ink in time to increase the contrast of the printing plate to adapt to the observation habits of human eyes.