Printing Dirty Analysis and Control (2)

According to the above analysis, the control of the grime prints is mainly controlled from the root cause of the grime-prepressing process (as shown in Figure 2).

1. Work hard to require all employees to work meticulously to improve the appearance of printed products.

2. Strengthen the examination of the film produced by the publishing house. If the quality of the film is poor (such as an actual density of <3.0) and the quality of the printing is affected, the film is rejected. If you use it excessively, there are more dirty spots on the film, or you need to re-copy or collage the film to remove the dirt on the film. If the text or pattern is severely damaged or if it is difficult to remove the dirty spots in the pattern, you can use the COPYDOT function of the scanner to scan, refill, and dirty the old film, and re-assemble the pieces.

3. The windows of all studios of the plate making shop should be closed. All personnel entering the plate making room should change shoes or shoe covers. The plate making room should be kept clean and dust-free, completely eliminating environmental pollution to the film.

4. Platemaking and printing personnel must do their own cleaning work.

5. Specification imposition process for easy printing.

(1) When the imposition staff sorts and trims the small-sized film for self-window, they should try to ensure that the film is rectangle-shaped, and leave a small margin around the small-size version to facilitate drying or repairing dirt.

(2) At the time of imposition, the adhesive tape should be placed as far as possible in the central position between the blanks of the two cores, so as to eliminate the tape marks during the double exposure.

(3) After the collage is completed, the number of films, including the pros and cons, self-reflection, and number of multi-impositions, will be indicated on the film envelope of each book. If the core is irregular, mark the irregular machine number of the core in the envelope to remind the printing personnel to re-determine the shielding position of the machine during the second exposure.

(4) When copying and copying, clean the worktable, polyester film base, copy machine glass, etc.

(5) After the imposition staff completes the imposition work, a red paper is used to make a table paper according to the size of the core, which is used for secondary exposure except dirt.

6. Make sure the job duties of the printing plate, improve the printing process, and strive to provide a clean PS plate for the next process.

(1) Check the table, printing plate glass, film, etc. again before printing.

(2) During the pumping process, the dirty spots on the layout must still be checked.

(3) Shaiban should follow the principle of “more exposure and less display”. For the field and text version, the exposure can be appropriately increased according to the actual situation to remove the fine spots on the layout.

(4) All the film and book products of the self-produced film must use the above-mentioned red-film table paper for double exposure, to remove the plate spots and tape marks.

(5) Equipped with a special revision table to facilitate the inspection of dirty spots that are difficult to detect with the naked eye (at present, our company uses a Taiwan Taisho 900 cm × 1130 cm revision table).

(6) After the dirt is repaired with the revised paste, the plate must be cleaned with clean water to prevent the plate residue from being stained after the plate is damaged.

(7) Baking solution should be evenly coated and allowed to dry before baking.

(8) The baking temperature should not be too high, generally 300 ~ 350 °C, to prevent PS plate carbonization.

(9) After baking, secondary development is required to remove the baking protection liquid on the plate to prevent it from being stained during printing.

7. Strengthen the maintenance of equipment, clean the plate guide roller of the plate processor and the roasting machine weekly, replace the brush of the plate processor regularly, and eliminate the dirt problem caused by hardware factors.

8. Clean the plate layout with a cleaning solution before printing to prevent the plate coating from being scratched and dirty.

9. If a small area is found in the production process, there is a defect in the layout, and there is a defect in the printing process, it may be the quality of the plate base. At this time, you should contact the supplier of the PS version.

10. The introduction of CTP system can solve the problem of dirty spots on the printing plate. At present, CTP technology has matured and the use cost has dropped. I believe CTP is not far from us.

In summary, there are many factors that contribute to the stains on printed products, especially for traditional book printing companies. Eradication of dirty tracks is not an easy task, but as long as the processes work together and persist, they will be able to solve the problem gradually. The quality problems caused.

Yangzhou Xinhua Printing Co., Ltd. Tang Xiaoping

Source: Printing Technology Publishing and Commercial Printing