How to find the cause and solve the problem of the ink problems in the screen printing process?

In the process of printing, if the ink color, scraping not clean, bite (eat or solute color) color, not dry, sticky, dry board, printing speed can not be fast, or the products with poor color force, low adhesion, orange peel, hang dirty, white spots, leakage etc. phenomenon, we can generally analyze from the following aspects:

1、Judge the scraper suitability and transferability 

If the ink on the screen printing plate roller scraping is not clean, the print will appear hanging dirty, running ink, blade, knife and thread and other phenomena.Print hanging dirty, running ink is also related to ink adjustment.Short stratification of ink will lead to dirty hanging; high ink viscosity may show ink running phenomenon, and have close contact with the correct angle and pressure of the scraper equipment.If only the full version of the ink scraping is not clean, with the finger press or replace the new ink is still not clean scraping, it may be a problem with the ink.If the new ink is a problem with the thinner in the ink.The solution is to replace the ink or dilutions and readjust the scraper.

2、Inspection of the printed substrate

If the ink presents printing leakage, white spots, orange skin color adhesion difference and other phenomena, the first should detect the appearance tension of the printing substrate and static giant fine.When the external tension of the printing substrate is below 35dyn, the ink adhesion is poor; when the static electricity is large, the orange skin will appear; when the ink is boring too fast, it is blocked, the printing leakage and white spots.The solution is: the printing substrate for the appearance and electrostatic treatment, to increase the humidity to the working site and adjust the ink with a slow dry solvent.

3、Check the purity and odor of the thinner

If the purity of the thinner is poor, the solvent residue of the print product will also increase naturally, and may remain on the print product odor.The first thing is to check the purity of the solvent, a brief test method is: pull 8cm wide white paper into the solvent wet and take out a little hard to wave, investigate the dull speed of the solvent and investigate whether it changes color, and then smell the residual smell on the white paper.White paper wave 8~15 times, the solvent evaporation is boring as normal.No boring solvent explains that the evaporation speed is slow, but otherwise, the evaporation speed is fast.If the white paper changes color, mark the solvent problem except for the rust of the solvent bucket.After the solvent evaporation, if the residual smell is smelled, the purity of the solvent is not good.

4、Use the slow-drying agent correctly

If the ink is used slowly dry diluent is not correct, printing will also lead to the printing of biting color, sticky phenomenon.The solution is to change the dilution formula of printing ink and adjust the boring function of printing ink.

5、Application of different ratios

In printing, different ratios of ink thinner, can adjust the boring function of the ink and its color concentration, viscosity.Adjusting the boredom of the ink also improves the printing speed and print clarity; adjusting the color concentration of the ink can reduce the pressure of the press glue roller and the workload of the ink scraper, thus facilitating the progress of the printing speed.The key of controlling the amount of ink, accustomed to printing speed and printing place room temperature is about the adjustment of printing ink viscosity.It is generally required to distribute the fast, medium, slow, or very slow drying thinner according to the printing speed, the depth or number of lines made on the printing roller, and the room temperature of the printing place.

6、From high viscosity to low viscosity application method

If your printing machine printing speed is slow, printing glass is relatively deep, the amount of ink requirements is large, at this time you need to use a high viscosity of the printing ink.If the opposite, use ink with low viscosity.In addition, diluents and attenants can be used to adjust the viscosity of the printing ink.

7、The application of uniform ink roll in the application of special color ink and metal ink

Special color ink requires consistent and uniform ink color.Metal ink is easy to precipitate, so it is very necessary to use the uniform ink roller in printing.In addition, when the use of special color ink, thinner and moderator had better be used together, should not use solvent alone to dilute.It should also be noted that metal ink is not suitable to increase solvent to dilution, can increase the right amount of attenator to adjust.

8、Application and mixing application of non-real solvents

Although the non-true solvent can not dissolve the cohesion resin in the ink, but using its characteristic, mixing it with the real solvent to dilute the ink can reduce the phenomenon of color bite in printing.

9、Test the adhesion of the printing products

The specific idea is to stick the tape on the print plate, flatten it with your fingers, and combine it closely with the print, and then gradually uncover it to half of the full length, and then quickly uncover the other half.Then investigate the number of ink stuck down from the print, if the stuck ink is less, indicating that the adhesion of the ink on the print is relatively strong, otherwise the adhesion is relatively poor.If the ink on the print is glued down for more than 40%, clarify that the adhesion of the printing ink on the print is unqualified.

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