Confusion of the hottest printing inking phenomeno

2022-08-19
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Confusion of printing inking phenomenon

release date: Source: China paper industry

inking, as the name suggests, is that the ink printed on the back pulls up the ink on the front seat, which is widely used in the packaging industry. Today, China paper industry takes you into Humen Color Printing Co., Ltd. to introduce in detail a drop ink phenomenon. There are two kinds of inking phenomena in Tiger color: one is ordinary printing inking, the other is UV inking, in which UV inking includes white inking and ironing before printing

since the end of 1998, the six color computer machine has changed from ordinary printing to UV printing. The first work order is "red flag canal". The ink used is Gao's UV ink. Customers complain that there are yin and Yang colors (colors change from different angles). Later, the company gradually switched to Hutou UV ink, which has good performance and no inking phenomenon. After a period of time, in order to reduce the material cost, the company changed from Hutou ink to HANGHUA ink (the price of Hutou ink is higher than HANGHUA ink). Later, with the change of the company's product structure, the company changed from ordinary gold cards to light gold printing, from no white ink backing to white ink backing, and some products changed from printing first to ironing first, and the product structure became complex. Therefore, the inking phenomenon increased significantly. At that time, the machine personnel were at a loss and had no way to start, and the workshop leaders had no better way to solve it. The only suspicious place was ink, Because HANGHUA ink has replaced Hutou ink, it was decided by the manufacturing department that the purchasing department should notify the ink supplier to come to our company to help find out the reason, so Mr. Satoshi, an expert of Japanese Donghua ink, came to our company to analyze the reason. He put forward several views: 1. HANGHUA and Hutou ink are both made by Japanese Donghua ink company, but the packaging method is different. 2. Change the binder of ink to reduce the viscosity. The proportion of pigment to binder is out of balance (volume ratio). When the pigment is less than binder, the viscosity of ink is small. 3. The inconsistent shape of pigments and the condensation of ink particles also affect the viscosity of ink. 4. Too high or too low temperature will also affect the viscosity of the ink. 5. The speed of the printing machine, due to the inertia of the high-speed machine, the viscosity of the ink should be reduced accordingly. Mr. sateng Haoyi went back to analyze and discuss the above five points, and finally provided a GW ink to replace 161 white ink. After trial, the inking situation was basically solved, but the good times did not last long. After about two months, the inking phenomenon appeared again, and even became more and more serious. Forced by helplessness, he only notified the engineers of HANGHUA ink to deal with it on site

Mr. sateng Haoyi came to our company for the second time and convened a symposium with the technical department, the staff of the printing machine, the ink mixer, the printing manager and the director. In view of the company's existing product structure and quality standards, Japan Donghua ink company specially developed an explosion-proof, folding resistant Hz ink for Tiger color, and the anti inking performance is also very good. About last May, the inking phenomenon began to appear again, sometimes slight, sometimes serious, and there was no rule. At that time, it was suspected that the ink quality was unstable, which led to inking, but after many tests, it was confirmed that the ink quality was relatively stable. Later, when the UV lamp was replaced with a new one, there was still ink drawing when the power was turned to the maximum. For example, the white ink of "best century dragon" and "best Mount Emei" was printed on light gold, and the ink drawing phenomenon was more serious. It took a long time to find out the reason: replace different papers to test, and it was concluded that light gold was easier to draw ink than ordinary gold card paper according to astm/gb/iso/jis/din and other standards, such as stretching, shearing, tightening, zigzagging, and various high and low temperature experiments, However, there is no tool to detect the adhesion of paper. Sometimes it takes a day (24 hours) or even longer to solve the problem of inking. President Kedeng has repeatedly informed the morning meeting of the manufacturing department that the average output of a machine is less than 30000 a day on two shifts a week. The sales department has also repeatedly mentioned that the delayed delivery time affects customers. The quality inspection of the quality control department is negative, the product quality is unstable, and even the missed inspection flows to customers, causing a bad impression to customers. The output is low. If the machine itself does not fail, it is a problem in operation. For example, to solve the problem of ink drawing, it is not only the problem of operation, but also the problem of material. Until the end of May 2000, istuv experts went to Shenzhen to participate in the printing technology training. Istuv experts provided a pen that can test the surface tension of gold card paper. After a period of testing, it was concluded that if the surface tension of ordinary gold card paper, light gold paper and silver card paper was lower than 34 dyne, it was easy to draw ink. The surface tension reached 36 dyne, and there was basically no drawing ink. The quality control department required the paper supplier to provide qualified paper based on this data standard, On one occasion, the supplier provided "refined moon free spring" silver paper. When the machine started printing, the inking was very serious. We changed the inks of different brands, reduced the viscosity of the inks, adjusted the printing pressure, and replaced the UV lamp. We thought of all the ways we could think of, but we couldn't solve the inking. Finally, we tested it with a surface tension pen, only 34 dynes, and the paper surface facial mask was electrostatic. As a result, the inking of this batch of papers was completely solved after the surface was coated with varnish

in addition to the influence of paper, ink and UV lamp power factors, film stacking technology is also the most common method of machine operation, which has a lot of factors. I will give two examples here: for example, one night, the six color machine was printing "Heibao color box", and there was a serious inking phenomenon. The machine staff adjusted and changed the color holder for many times. As a result, it took about 13 hours in the evening, and it could not be solved by the next morning, There are many ways of communication for machine computers to receive digital signals. Both shift handover and director shift handover emphasize that the surface tension of the paper cannot meet the requirements, and emphasize that the paper is returned to the supplier. After the day shift machine takes over, reduce the first white ink, increase the color water in the back, and reduce the pressure in the back. As a result, the inking problem is solved. Example 2: in October, 2001, the old five color machine printed "boutique seabird box", with a feeding number of more than 200000, and about 100000 car heads printed, the machine proposed that there was inking. At that time, the machine suspected that the UV lamp power was not high enough, and reported to me that I felt a little strange that there was no inking phenomenon in the UV lamp like the night shift, so the captain was asked to check whether the adhesive tape behind was used for too long, resulting in uneven surface, Finally, after replacing the new adhesive tape, the inking phenomenon was solved. However, there is a mystery in my heart that cannot be solved. I remember that in March 2001, a batch of "treasure Lanzhou" was sent to the Changming printing factory in Daling mountain for printing. Because the machine personnel there did not touch the UV printing with light gold paper and white ink, there was nothing to do with the bit ink. I cooperated to solve it. The UV lamp power was only turned on to 60%. I thought that the white ink was not completely dried, so I asked the machine personnel to turn on the UV lamp power to 80%, As a result, the ink drawing was more serious, and the UV lamp power was turned back to 60%. The situation has improved again. So far, I don't know what the reason is

printing inking has puzzled me for two years. In these two years, I have explored and analyzed UV inking, constantly summarized experience and lessons, and now listed relevant solutions:

first, the surface tension of paper must meet the requirements, the surface tension of ordinary gold card paper, light gold, silver card and so on must reach more than 35 dyne, and the white card glass card paper must have a certain surface strength, that is, the surface strength is p ≥ x + U + n

p-the binding force between fiber and filler and rubber

x-the adhesion of ink to paper

u-inertia force (stripping tension)

n-the adsorption force and viscosity of blanket

second, master the power of UV lamp, understand the service life of UV lamp, and reasonably arrange the sequence of UV lamp

III. properly adjust the viscosity of the ink used, and add an appropriate amount of debonding agent to the ink (the departmental standard is not more than 5%), so as to improve the adhesion of the ink to the paper

IV. properly adjust the printing pressure to reduce the pressure between the rubber cylinder and the embossing cylinder, or choose an appropriate printing speed, preferably with an appropriate reduction in speed, so that the stripping force between the rubber blanket and the paper can be reduced after embossing

v. ensure that the adhesive tape is smooth. If the surface of the adhesive tape is rough, the friction will be large, and the tension will increase. If necessary, replace the new adhesive tape when the electromechanical drive belt is loose

VI. to control ink painting, it is necessary to consciously reduce the water volume of the front printing seat and increase the water volume of the rear printing seat

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