Detailed introduction to the most popular photosen

2022-08-02
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In recent years, water-soluble solid photosensitive resin plate has been favored by small and medium-sized printing manufacturers because of its advantages such as simple plate making process, low cost, no pollution, good ink transfer performance, high printing resistance, light plate material, short plate making cycle, and can form a complete set with computer laser phototypesetting system

photosensitive resin plate is a relief plate with photosensitive properties, which is made of synthetic polymer materials as film-forming agent and unsaturated organic compounds as photo crosslinking agent. Almost all photosensitive resin plates are irradiated by light (mainly ultraviolet light) to produce cross-linking reaction between molecules, thus forming an insoluble relief image. Photosensitive resin plate can be divided into two types: solid type plastic and liquid type. The cost of solid series prefabricated plates made of saturated light sensitive resin is relatively high, but the quality is relatively good. They can be used to make commodity packaging, trademark plate and line plate; The liquid type series of coated plates composed of unsaturated polyester resin (simply speaking, when using, prepare photosensitive liquid for base production, and then apply and pour resin for photosensitivity and production) are relatively cheap and suitable for rough text line plates. In the actual operation of solid photosensitive resin plate making process, the following problems often occur. Only through comprehensive analysis, differential treatment and identification of the root causes of the problems can we solve the problems

I. the text, lines and pattern lines of the resin version are too thin and small. Small characters fall off outside the wide product line and at independent points. Small lines are bent in the process of making the resin version. There are common problems such as the bending of thin lines and the falling off of small characters and independent points

main reasons: 1. Insufficient exposure time of resin plate; 2. The negative film has small contrast, foggy and unclear; 3. Improper baking of resin plate and heat curing treatment; 4. When brushing the resin version, the water temperature is low, the washing time is long, the bristles are too hard, and the version is too deep; 5. The pressure is too high when printing on the machine, and the adjustment is improper

solution:

1. When making resin version, when encountering small words, lines, patterns and independent points, it is necessary to master the correct exposure time. The exposure time of the 3KW gallium iodide lamp is about 20min. The exposure time must be longer than that of the normal version. In this way, the small lines, words and independent points can stand and not fall off. Due to the long exposure time, the side slope of the resin plate is small (about 70), and the image and text base is firm

2. When baking the resin plate, drying and heat curing, generally, the oven temperature is controlled at 60-80 ℃ to evaporate the water on the plate; If the drying temperature is too high, the resin version is easy to blister

3. The operator is required to have excellent darkroom technology, and the contrast of film processing should be as human as possible, without fog, and the text and lines should be smooth and smooth without missing pen and stroke

4. When making solid resin plate, whether it is automatic plate brushing by plate making machine or manual brush, the water temperature should be controlled at 5060 ℃ and washed until the bottom base is exposed. Brush the resin version by rotating. If you only brush the version on one side, it is easy to brush the side and slope, resulting in the bending and falling off of small lines; When you brush the plate, you should choose the brush with soft and appropriate hair. If the hair is hard, the small text will be damaged; Brush tree Hainan will be built into a perfect shipping key infrastructure. Pay attention to the depth of the brush plate. The brush plate does not have to be washed to see the base. If the brush plate is too deep, it is easy to brush off the text, lines and patterns on the plate. In addition, pay attention not to take too long to wash the plate

5. When the resin plate is printed on the machine, the ink roller and the resin plate shall be properly adjusted. The pressure between the resin plate and the embossing cylinder shall be adjusted. The printing pressure of the resin plate shall be less than that of the copper zinc plate and the lead type. Avoid crushing the small text lines of the resin version by the inking roller and the embossing cylinder due to excessive pressure, which will affect the printing resistance

II. The text and line version are ambiguous when making resin version

main reasons: 1. Excessive exposure; 2. Vacuum absorption is not solid when drying; 3. The film contrast is small and unclear

solution:

1. Master the accurate exposure time of resin version. In particular, hollow text and lines are the easiest to paste version. When designing, try to make the text thicker

2. The plate printer should have strong suction. If the suction is not solid, there is a gap between the resin version and the film, and ultraviolet rays will be emitted from all around, resulting in a photosensitive paste

3. Before printing, carefully check whether the apricot negatives are pasted, with good light transmittance, contrast and clarity, so as to meet the requirements of plate making quality

III. the resin plate cannot be washed away.

main reasons: 1. The resin plate has exceeded the shelf life, which will cause valve and oil circuit blockage, or light leakage during production, storage and transportation, and the resin plate will be photosensitive and hardened; 2. The water temperature is too low when washing and brushing the plate; 3. The film darkroom treatment is poor, and the film has poor shading and low density

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