1. The treatment of printing dew white is the most common quality problem in the production of corrugated boxes, which is also the most difficult to put an end to. The reasons are: poor ink absorption performance of paper; Plate dirty; There are chips, dust, etc on the board. The traditional way to deal with these problems is to manually change the box, or increase the frequency of manual erasure. These methods will play a certain role in the objective, but the improvement effect after changing the box is not big, and easy to cause the efficiency decline; Wipe version will also cause water, electricity, artificial waste.
After long-term observation and analysis, the author believes that in the process of equipment installation, maintenance and management, the key to solve the printing dew lies in dust removal. Dust is the main source of single pole points when the paper, based on this, the author in cardboard production line computer cross-cutting knife after two years ago and the printer paper department has installed the electrostatic suction aspiration device, use the hair drier, in front of my computer cross-cutting knife to monolithic knife hidden in the grooved as “paper about dust blowing out or blow away, Then in the computer knife after the paper receiving rack using electrostatic suction suction device to absorb the paper scraps. In the gap between the feeding rubber ring and the feeding wheel of the printing press, the dust on the paperboard is absorbed by electrostatic suction to ensure that the printing surface is clean and dust-free. Under such conditions, when the paperboard enters the printing roller, the ink is accessible and the ink is uniform. After such improvement, the printing effect of the product is greatly improved, and the phenomenon of printing whiteness caused by dust is fundamentally overcome.
Two, overprint location processing
Now commodity packaging more and more attention to the artistry of the pattern, three-dimensional sense, so that consumers from the outer packaging to feel the perfection of the purchased goods. In order to achieve this goal, packaging printing must use multicolor printing, that is, multicolor overprint.
In the overprinting process, there is often a mismatch between the latter color and the former color superposition or positioning position, resulting in the printing pattern can not reflect the design effect of product packaging, or even different, completely destroying the image of the product.
In view of this special problem, the author’s company after a period of time in-depth field investigation and study, on the electronic control reflected speed to mechanical coordination tolerance precision, a detailed calculation, on the existing equipment for a number of improvements, at the same time formulated the relevant equipment maintenance measures.
1, improve the precision of printing cylinder phase positioning
The phase positioning of printing drum is controlled with encoder and counter, if the accuracy of counter is too low, it will cause the position of encoder is not accurate, and the printing is out of position. Ju鉩 ounter reflects the speed of 3k, but in the positioning error is often ±1mm, after discussion with Taiwan electronic control company, the production of 5KRcounter, so that the printing drum positioning error is reduced to ±0.4mm.
2, timed lubrication, detection of transmission machinery
In the process of feeding paper, if the transmission machinery can not keep a good and balanced operation, the position of each cardboard will change, resulting in printing and sleeve position, so it is very important to carry out the correct maintenance and detection of the equipment. Can develop daily pre-start-up check list, including lubrication maintenance. At the same time, the paper feeding wheel, the paper feeding ring wear limit, unqualified must be turned over, re-coated or replaced, to overcome the cardboard in the process of walking, oblique position and other phenomena.
3, the use of suction paper
The traditional printing press uses the upper printing and can only use the feeding wheel to transfer the board, while the new printing press uses the advanced technology of the lower printing and the upper suction to transfer the board. The suction paper feed uses the wind force to adsorb the cardboard on the conveyor wheel, and its suction is uniform, not out of position, not inclined, and the curved cardboard is sucked flat, printing alignment, ink more uniform, more flat.
Three, printing ink bad treatment
Inking in addition to paper and offset problems, in the equipment and inking roller technical treatment problems.
In high-standard carton printing, the roller with more than 250lpi is used, and its mesh is most easily blocked by ink slag, resulting in uneven ink, insufficient ink, ink resulting in uneven ink, insufficient ink, black and other phenomena. The traditional method is to use water to clean the black roller, whether the water scrub ink roller or cleaning agent scrub, the effect is not ideal, a new ink roller use less than a month, the effect is not as good as before.
The author’s company through long-term exploration, test, think that the following methods can effectively solve the printing ink bad influence.
1. Add a filter in the ink bucket to prevent ink particles from being transferred to the ink roller.
2, regular (generally half a month) use roller deep cleaning agent, circulation cleaning.
3. Wash the ink roller with dripping water and dialysis the mesh of the ink roller with a magnifying glass 60 ~100 times every day when you get off work. No ink residue can be left.
Through the maintenance of the above points, the ink roller on the ink effect can always maintain good.
The above several printing technical problems in the actual production of carton product quality is very important, through the understanding and improvement of equipment, as well as good maintenance, can produce customer satisfaction products, improve the comprehensive benefit of the enterprise.
Post time: Aug-20-2021