Attach importance to the work of printing on the board (below)

Correct exposure must be ensured by proper flushing. If the exposure is slightly biased, it can theoretically be remedied with flushing, but the scope is very small and is not advocated from the perspective of standardization. Whether the exposure is correct or not is the key. Flushing is a guarantee. The washing of the printing plate used to be called "developing", but the washing of the printing plate and the development of the silver salt material are essentially different, so this article uses flushing instead. The purpose of rinsing is to dissolve the decomposed material, and the more clean and thorough the solution, the more exposed the hydrophilic layer of the sand to prevent dirt or scumming, but it must not affect the oleophilicity of the graphic part.

1. Selection of rinse solution. Positive rinsing fluids generally consist of rinsing agents (sodium hydroxide, sodium silicate, etc.), protective agents (sodium phosphate), surfactants, and solvents. The current sales of the PS version have a large supporting fluid, according to the instructions carefully prepared or diluted to use. According to the characteristics of printed products, the rinsing liquid can be properly adjusted. For example, the alkalinity of the rinsing liquid in the text printing version can be more appropriate, and the fine reticle version based on the image can be relatively buffered in the rinsing liquid. The light, medium and dark should be taken into consideration. Levels. The performance of the rinsing fluid in the stencil, graphic and text versions can be different.

2. Washing fluid concentration should be appropriate. Concentration refers to the relative amount of rinsing agent, which is proportional to the rinsing speed. When the concentration is high, the rinsing speed is relatively fast, the dots are easy to shrink, the strokes are easy to become thin or broken, the small dots are easily lost, and the resistance force is decreased; when the concentration is low, the rinsing speed is decreased, the layout is easy to get dirty, and the shadows are easy to paste. Therefore, strictly formulated according to the formulation or product requirements, the application of distilled water or softened water.

3. Control flush temperature. The flushing speed of the PS plate is proportional to the temperature of the rinsing liquid. The higher the rinsing temperature and the faster the speed, the more thoroughly the exposed parts are dissolved. However, the dots are easy to shrink and the small dots are easily lost. The flushing temperature is low, the rinsing speed is slow, and the layout is easy to get dirty. , dark tone easy to paste version. Generally controlled at 23 °C ± 3 °C as well. Because of the great geographical conditions in China, the temperature difference between winter and summer is very different, so the flushing temperature can be adjusted properly. However, the flushing temperature of a company must be relatively stable and cannot be high or low.

4. Control the flushing speed. Flush with the machine to express the speed, manual wash time expressed. The speed or time of rinsing is related to exposure, media performance, and rinsing fluid performance. Under certain conditions, the flushing speed is slow or long, and the flushing is thorough, but the dot is easy to shrink, and the small dot is easy to lose; the speed is fast or the time is short, the flushing is not easy and thorough, and the dark tone is easy to paste.

5. Rinse fluid to add. In order to maintain the stability of the rinsing liquid, a new rinsing liquid is added according to the rinsing consumption during use. The use of the washing machine is mostly automatic replenishment device, the supplement volume can be adjusted; manual flushing according to the amount of rinsing plate timing supplement or replace the new flushing fluid.

6. Pay attention to circulation and agitation of the rinse solution. As far as possible, the rinsing liquid is in contact with the photosensitive layer to ensure uniform flushing. The dissolved substances must be completely dissolved and no local residue is allowed.

In short, to ensure that the image is reproduced in full scale, all indicators should be comprehensively controlled. If the rinsing fluid has strong performance, high concentration, high temperature, slow speed, more replenishment, faster stirring, easy to shrink the dots, small dots are easy to lose, small strokes become thinner, which is more favorable for shadow tone; on the contrary, the performance of the rinsing fluid is buffered and the concentration is low. , Low temperature, fast speed, low supplementation, insufficient circulation or stirring, dissolving the blank part is not easy enough, and the layout is easy to get dirty. Therefore, exposure and washing of the printing plate must be controlled as a whole (see Figure 6).

Fourth, the quality requirements of the printing plate

The quality of the printing plate has common requirements. According to different printing suitability conditions (comprehensive adaptability of paper, ink, imprinting process, printing environment, blanket, fountain solution, etc.), some indicators allow certain fluctuations.

1. The rules on the layout are complete, and the layout of a set of rules must be consistent.

2. The layout is clean, the graphic is not damaged, the image can not have trachoma or dead spots that should not be connected; the text is complete, there can be no lack of pen strokes; maintain good lipophilicity; the blank part must completely dissolve the decomposed photosensitive layer Drop off, maintain good hydrophilicity. If there is a substance that is completely dissolved in the blank area, it can be removed by removing the dirt, but the operation must be cautious. The dirty agent must not enter the picture and it should be cleaned with clean water.

3. Normal operation, the plate can not be scratched, dirty and horseshoe India and other hard injuries.

4. Complete image adjustment, complete text, in line with the original or printing plate requirements. Different papers, different printing speeds, and indicators of each tone of the image are allowed to fluctuate (see Table 1). The core is that the middle version of the brilliance version must be shallow compared with the original version. If it is not light or dark, the printing plate cannot be used.

It should be pointed out that the same set of original paper and different paper, only rely on exposure and flushing adjustment is limited, should be in the plate when the calibration, the number of lines, the use of color regulation. For example, if newsprint is printed on a high-speed machine, the plate-making scale may be appropriately scaled. The number of screen lines is relatively coarse, and the basic colors are relatively full, while the opposite colors are used less. Table 1

Bright spot 50% outlet dark spot

Area area

Coated paper 2% 47% 97 to 98%

Offset paper 3 to 4% 46 to 47% 96 to 97%

Newsprint 4 to 5% 45 to 46% 95 to 96%

Tonal adjustment

Paper type

Figure 6 Changes in the three conditions of flushing outlets

5. If the stencil is not used right away, a layer of hydrophilic gum arabic or other hydrophilic protective glue should be rubbed to prevent the white parts from being oxidized. At the same time, in order to prevent the dust from contaminating the layout, cleanliness should be avoided. Light.

6. If it is a long-run printing (more than 25,000 printing), in order to enhance the stability of the basis of the graphic, wear resistance, increase the amount of print, reduce the number of printing or changing plate, to maintain the consistency of the printing product, to implement the baking version . The plate layout that needs to be baked must be clean, and the baking temperature and time depend on the amount of printing.

Five, need to explain a few issues

1. It is best to focus exposure and rinse. Most print companies in China do not match the printing capacity and printing capacity. The printing capacity is greater than the printing capacity, resulting in idle or intermittent use of printing equipment. Shaiban should be continuous operation, continuous job exposure and rinse the indicators are relatively stable, easy to operate and control, on the contrary intermittent operation of the indicators are not easy to control, affect the quality of printing. Therefore, we should plan well and implement centralized operations as much as possible.

2. The printing principle of negative and positive images is different. The negative plate type plate material is photopolymerized, and the photo frame shows that the polymerization occurs and the oil is oleophilic. In order to increase the photopolymerization degree of the photo-textured area, a sufficient amount of exposure is required, so that the dots will be enlarged and the lines will be easily widened. Therefore, the original plate must be relatively shallow, and a relatively shallow layer curve should be selected; The site has enough density (usually over 3.5), the lower the density of the graphic parts, the better, so as to meet the printing requirements.

3. The quality of the plate must be improved and the variety increased

plus. China's plate production has made significant achievements and the number has been met, but there are limitations in quality and variety. The current positive-printing PS plate can meet the requirements of drying 200 lines/inch or less, and can produce more than 200 lines/inch or FM network dots. It has incompatibility in terms of resolution, grain status, and photosensitive layer. If the brightly adjusted small outlets are kept well, the decomposition of the dark space will not be complete (more than 90% will be obvious); if the dark tone meets the requirements, the small outlets will be easily lost; when the sun is tuned, the small outlets will be missing. The same gradation of the thin network cable or the FM network is longer than the total length of the edge of the coarse network line. Therefore, the requirement for the plate is high and the operation is difficult.

The use of a recycled version has the advantage of low cost. It is possible to use as a proofing version or a short text version, but printed high-grade image prints or flat-line text prints are not suitable and should be considered comprehensively.

4. The traditional printing needs the traditional proofing. The conditions and requirements of the sun-printing pattern and the printing plate are basically the same. Because the proofing is round and flat, the speed is slower than the value of the printing dot, so the printing version should be deeper than the printing plate. If you use the same conditions to print, you can use the amount of exposure adjustment, the general printing version of the sun exposure is twice the proofing version to meet the requirements.

5. Different printability has different requirements. This difference can be taken into account when making plates, and it can also be adjusted during printing. It is best to take both solutions into consideration. However, the printability conditions are still not clear when a considerable part of the company is making plates. Therefore, the use of conventional plate-making printing needs to adjust the depth of printing plate according to printing conditions (mainly paper and printing speed) with exposure and rinsing. The same set of printing plate coating paper is suitable. Printing newsprint cannot.

6. Build regulations and strengthen management. Regulations or documents are the basis for all relevant personnel of a company to comply with certain procedures. The management is fundamental for all enterprises. Management is to design and maintain a good environment so that people can accomplish the set goals efficiently in groups. Modern management advocates prevention-oriented pre-management, prepares regulations or documents in advance, and works according to regulations to overcome blindness and operational arbitrariness in the command; advocate process control and solve problems in the process to prevent substandard products. Appearance; advocates people-oriented, service-based human, material, environmental management on-site management. According to the "Beijing Industrial Enterprise on-site management of three types of standards" requires the assessment of six categories (labor, methods, objects, special management, environment, overall category), 108 indicators. Combining with the actual printing enterprises, the author summarized 10 categories, 41 indicators, and eight negative indicators. Through the management and assessment of various indicators, the site environment is rectified, the labor organization is standardized, the process routes are optimized, the rules and regulations are improved, the quality of employees is improved, comprehensive advantages are reflected, and production safety is ensured. The goal is to achieve a clean environment, strict discipline, orderly logistics, well-equipped equipment, accurate information, balanced production, and team optimization. If this can be done, the printing quality will be guaranteed (see "China Printing", 1999, Issue 5, "Some Issues on Site Management").

Work involved in the printing process is very wide, in this combined with their many years of work talked about some experience for reference, please correct my colleagues in the industry.

Source: Wenzhou Material Printing Market