Possible printing faults caused by the hottest ink

2022-08-10
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Possible printing faults caused by ink

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core tips: when the ink is reproduced in printing, it is not colored, scraped cleanly, bitten (eaten or dissolved) color, does not dry, sticky back, dry version, printing speed can not open, or there are poor coloring power, low adhesion, orange peel color, flying silk, galling, dirty hanging, white spots When missing printing (painting) and other phenomena, it may be that your ink has a problem. This paper analyzes it in detail

[China Packaging News] when the printing ink is not colored, scratched cleanly, biting (eating or dissolving) color, not dry, sticky back, dry version, printing speed cannot be opened, or there are phenomena such as poor coloring power, low adhesion, orange peel, flying wire, roughening, dirty hanging, white dots, missing printing (painting) on the printed matter, it may be that there is a problem with your ink. This article analyzes it in detail

1. Judge the suitability and transferability of the scraper of the ink

if the ink on the gravure printing cylinder is not scraped clean, the printed matter will be dirty, ink running, knife wire, knife line and other phenomena. The dirty hanging and ink running of printed matter are related to the adjustment of ink. The temporary stratification of ink can cause dirty hanging, and ink running will occur when the ink viscosity is high, but it is closely related to the correct and appropriate angle and pressure of the scraper device

it is only when the full version of the ink cannot be scraped, and it cannot be scraped by pressing with your fingers or replacing the new ink, that there may be something wrong with the ink. If it can be scraped clean after replacing the new ink, there is something wrong with the diluent added to the ink

solution: replace the ink or diluent, and readjust the scraper

2. Inspection of printing substrate

ink has phenomena such as missing printing, white spots, orange peel, poor adhesion, etc. first, the surface tension and static electricity of the printing substrate should be detected. When the surface tension of the printing substrate is lower than 35dyn, the ink adhesion is poor, orange peel will appear when the static electricity is high, blocking will be formed when the ink dries too fast, and there will be missed coating and white spots on the printed matter

solution: conduct surface and electrostatic treatment on the printing substrate, increase humidity in the workplace, and adjust the ink with slow drying solvent

3. Purity and odor test of diluent

poor purity of diluent will increase the solvent residue of printed matter, and may also leave odor on printed matter. First check the purity of the solvent. The simple test method is: pull a 200px wide white paper strip and put it into the solvent to get wet, then take it out and wave it with a little force, observe the drying speed of the solvent on the white paper strip and whether it changes color, and then smell whether there is any residual smell on the door paper strip

when the white paper strip is waved for 8 ~ 15 times, the evaporation and drying of the solvent is normal, and the evaporation speed of the non dried solvent is slow, otherwise the evaporation speed is fast. The discoloration of the white paper strip, except for the rust of the solvent barrel, indicates that there is a problem with the solvent. The residual smell after the solvent volatilizes is that the purity of the solvent is not enough. Scrape the original ink and diluted ink on the film, and test after drying

a large scraping residue of the original ink and a small scraping residue of the diluted ink indicate that it is normal, on the contrary, there is a problem with the diluted solvent. If the scraping sample of the original ink has residual odor, there is a problem with the ink. If there is peculiar smell in the scraping sample of the diluent ink, it proves that the solvent used in the diluent is impure

treatment method: change the ink or adjust the solvent of diluent

4. Correct use of slow drying agent

incorrect slow drying diluent used in printing ink will lead to color biting in printing and backsticking in printing

solution: change the diluent formula of printing ink and adjust the drying performance of printing ink

5. Application of diluents with different proportions

different proportions of ink diluents in printing can adjust the drying performance of the ink, the color concentration of the ink, and the viscosity of the ink. Adjusting the dryness of the ink is conducive to improving the printing speed and the clarity of the printed matter

adjusting the color concentration of the ink can reduce the pressure of the embossing roller or the workload of the ink scraper, which is conducive to the improvement of the printing speed. Adjust the viscosity of printing ink, It is precisely to control the ink amount or adapt to the printing speed and printing place room gb13022 (9) 1 "test method for tensile properties of plastic film" that describes the fixture as follows: "The experimental machine should be equipped with the key to proper fixture temperature. Commercial aircraft use countless supports and system accessories. According to the printing speed, the depth or number of lines of text production on the printing plate drum, and the room temperature of the printing place, the diluent of fast drying, medium drying, slow drying or ultra slow drying should be prepared.

6. The use method from high viscosity to low viscosity

the printing speed is slow, the text production of the printing plate is relatively deep, and the amount of oil and ink is required Large, need to use high viscosity printing ink. The printing speed is fast, and the production of printed plates and graphics in China's energy distribution not only has obvious regional differences in the total distribution, but also requires less oil and ink, so it should be printed with ink with low viscosity. Use diluent and diluent to improve the viscosity of printing ink

7. Use of ink leveling roller in the use of spot color ink and metal ink

spot color ink requires that the ink color is consistent and uniform, and the metal ink is easy to precipitate, so it is very necessary to use ink leveling roller in printing. In addition, in the use of spot color inks, diluents should be used together with diluents, and solvents should not be used alone to dilute. Metal ink should not be diluted with solvent. The correct method is to add diluent appropriately to adjust

8. Use and mixed use of non real solvents

although non real solvents cannot dissolve the connecting resin in the ink, using its characteristics and mixing with real solvents to dilute the ink can reduce the phenomenon of color biting in printing

9. Adhesion test of printed matter

stick it on the printed matter with adhesive tape, flatten it with your fingers, and closely combine it with the printed matter, then slowly lift up half of its full length, and then quickly lift up the other half. The less ink adheres from the printed matter, the stronger the adhesion of the ink on the printed matter. On the contrary, the adhesion is poor. If the ink on the printed matter is stuck down by more than 40%, It indicates that the adhesion of the printing ink on this print is unqualified

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