(This article is an original article from Bisheng. It is forbidden to reprint, and reprinting must be corrected)
We often encounter in our daily work that the PS version that has already started printing on the machine has found quality problems, and then we need to unload the PS version on the printing machine again, reprint the version, and repeat the process of publishing. Since this process includes the printing time of the printing plate, and the time of repeating the version, this has a certain impact on the production efficiency. At the same time, there will often be mutual blame in both platemaking and printing. For example: the blank part is exposed due to insufficient printing or improper development, and a small amount of photosensitive adhesive film remains on the plate surface, causing the blank part to become dirty. The best way is to make a reasonable judgment on the printing quality of the PS plate before the printing plate is printed on the machine. If there is a printing plate quality problem, make up the printing in time to avoid the situation of downtime and other plates.
Below we will discuss how to judge the quality of printing plates.
· Check the appearance quality of the printing plate
Refers to the external performance state of the printing plate. The basic requirements are that the plate is smooth, clean, and evenly rubbed, without broken edges, creases, scratches, stolen goods, and ink dots.
· Check the layout specifications
Check the plate size, graphic size, bite size, folding size, folding relationship, etc. If the size error of the layout is less than 0.3mm, the color version must be correct and not skewed.
· Inspection of graphic content
The basic content is correct text, no defect words, no blind words, the corresponding content of the plate and the text is consistent, the direction is correct, the PS version of the photosensitive adhesive film is strong, not false, and does not take off the film and the version. When the multi-color set is exposed, the color version is complete. The rule line is the basis and benchmark for the four-color overprinting of offset printing. It is required to be thin and black; at the same time, the rule line and corner line are also the standards for cutting the paper edge printed products, so make sure that the rule line should be complete and complete; The position of the rule line, corner line and trailing line ensures that the product size on the printing plate is larger than the finished product size after cutting, to avoid that the corner line and rule line cannot be cut off, and it is unsightly when attached to the printed product.
· Check the quality of outlets
The dots in the printing plate should be full, complete, smooth, no damage, no scratches, no hollow, and few burrs. Observe and analyze 5% of small dots, 50% of dots and 95% of dots with the help of a magnifying glass of 5 to 10 times, and compare the corresponding color dots of the offset printing plate and the monochromatic color overlay of the proof sheet. If the dot size of the highlight part, middle part and dark part basically match with the print sample, it means that the printing plate depth is in line with the requirements of the machine. If the dot is enlarged, it means that the tone is too deep, and the dot becomes small, which means that the tone is too shallow. If the dots shrink and the highlight dots are lost, it means that the graphic color is light, and if the dots expand, the dark white dots are dead, indicating that the graphic color is dark. In general, 98% of 2% highlights and dark tones should be well reproduced.
By checking the depth of the tone level of the printing plate, you can observe whether the PS plate printing, electrical gradation level, dot smoothness, and whether there is fog or unclear film.
· Offset printing plate color difference and inspection
After the printing of the offset PS plate is developed, it is necessary to check the color of the printing plate according to the proofing color sample to see if it meets the needs of overprinting. The printing plate with text, lines, and graphics is easier to distinguish the specific color of each printing plate according to the color draft; for those overprinting plates that are divided into four colors, there is a certain difficulty in identifying colors, which requires us to make a version 3. When imposition, be sure to mark the color of the edge of the printing plate, such as: yellow (Y), magenta (M), cyan (C), black (K), so when you print on the machine, just look at the color English words can distinguish the colors. In short, all products with overprint of more than two colors, such as trademarks printed by offset printing, electronic color four-color overprinting, book covers, etc., should be marked with color blocks so as not to confuse the colors. In addition, there are often some other substitute symbols on the printing plate to indicate the color. The operator should also have a certain understanding and strictly avoid the phenomenon of making the printing plate wrong. See the attached table below:
· Examination of graphic and blank parts of offset printing plates
The blank part of the offset printing plate should be clean, tidy and free of sullenness. It should be checked carefully to see if there are any dirty spots or scratches on the layout, the oxidation is drying up, and whether there is any leaky photosensitive film. For the dirty areas on the printing plate, you can use the PS version of the revision paste to remove the dirt. The leaked photosensitive film can be corrected with the PS revision pen. For some small layouts, there are problems with plate patterns, dirty spots, etc., and it is not necessarily a new printing plate. The plate is not dirty due to exposure and development. You can wipe it with diluted developer to make the printing plate meet the printing requirements. Save as much as possible to reduce the consumption of raw materials and increase the printing plate durability.
If a comprehensive analysis is done, the right medicine can help reduce the consumption of finished products and improve the benefits.
In order to ensure that the quality of offset printing plates is stable and reliable, the operators and quality inspectors of the plate-making process must carefully check the printed plates, so as to identify plate-making quality problems before large-scale official printing and correct them in a timely and effective manner, thereby achieving improvement The quality of printed products should be well connected between plate making and offset printing.
modern dining table,narrow dining table,dining tables set,dining room furniture
Kumusi (Dongguan) Furniture Co., Ltd. , https://www.kcoffeetable.com