One failed printing

A small printing factory of Maoming Music Arts Computer Paper Printing Co., Ltd. undertook a batch of color printing. Due to the printing quality problems, it was returned by customers, causing some economic losses to the factory. This batch of printed products is full of yellowing, unclear levels, and lack of gloss. After understanding the whole process of printing, the author analyzes the reasons and summarizes them for reference by peers.

1. The printing equipment itself is not adjusted

Impression of uneven pressure on the impression cylinder, there is a certain enamel clariness is not tight, when the printed version of the cyan, bad transfer of paper, when the phenomenon of paper rolling rubber, even rolled into the ink roller, resulting in more downtime, ink Uneven thickness and inconstancy of ink volume control make it difficult to superimpose in subsequent sequences.

2. Printing color sequence error

It is understood that the batch of printing products is completed by a four-color monochrome machine, and the printing color sequence used is Chongpinhong, a yellow and a black. Due to the poor transparency and strong coverage of the yellow ink used, the ink ink layer is thicker and the dots are significantly enlarged, which makes the surface of the prints look like a light yellow layer. The cyan plates and magenta plates cannot be truly reproduced. If the yellow transparent ink is used or the color sequence of yellow-pink-pink-cyan is used for printing, the yellowing of the printed matter can be completely avoided.

3. Excessive dusting

Due to the lack of experience in powder spraying, the operator of the plant used a pack of dusting powder during the printing process of printing four colors and overprinting a total of 40,000 printings. The entire workshop was filled with dust on the day of work. Due to the excessive use of dusting, it has been difficult to paint in the last color. Under the effect of dusting, the black text version of the fourth color printing had a serious phenomenon of chalking, and the lack of writing in the text severely affected the quality of printed products.

In fact, as long as the spray can play a role in accelerating the drying of the print and avoiding the stickiness of the printed product, once it is used excessively, it will result in dull colors and difficulty in overprinting. Practice has proved that the previous color is not sticky. If the imprinting is not completely dry, the next color superimposition is the best. Therefore, the amount of dust to be sprayed must be controlled properly, and it can be used when not in use.

4. Ink and ink imbalance during printing

If the amount of water is too large, it will directly affect the quality of printed products. Because the amount of water is too large, it will easily cause ink emulsification, resulting in lower ink transparency, dull printed products, seriously affecting the reduction effect of overprinting. The gloss of printed ink film mainly depends on the oxidized conjunctiva of the ink to make the surface smooth and bright. If the ink is over-emulsified, the gloss of the print will be reduced and the drying speed will be slowed down. In order to prevent the back of the printed product from picking up the dirt, the operators did not reduce the amount of water supply, but they continued to increase the amount of powder sprayed so as to affect the continuous overprinting, resulting in the phenomenon of overprinting.

During the printing process, increasing or decreasing the water supply and ink supply of the layout will change the depth of the ink of the printed product. At this time, it should be adjusted in time according to the specific circumstances, but special attention should be paid to preventing the practice of water and ink. When the amount of water is too large. When the ink becomes light, do not blindly adjust, that is, mistaken for a small amount of ink and increase the amount of ink, which will undermine the ink balance, resulting in a vicious cycle, leading to severe emulsification of ink, light print quality is affected, while printing Can't work properly.

In short, when printing, you must always look at the printed sheets and be good at comparing them with the proofs. Once they are found to be different, they should be processed in a timely and accurate manner before printing. Printing requires the accumulation of experience and the improvement of technology. For beginners, the correct understanding of failure and the acquisition of experience is the only way to success.