Analysis of Printing Failure of Woven Bag Ink

First, adhesion is not strong

Failure reasons: 1. Substrate surface and film or woven bag surface is too smooth (untreated or poorly processed). 2. Ink complexes (ie additives) were selected improperly or in insufficient quantities. 3. The dissolved hydrogen bond strength of the ink system is too different from the hydrogen bond strength of the woven bag substrate. Remedy: 1. The woven bag substrate surface reaches about 38 Dyne. 2. Add 5% of chlorinated paraffin before drawing the filaments. 3 ink selection should be very careful (the same nature). 4. The use of ink should be appropriate, as long as the viscosity is small and the ink system resin content is high. 5. Increase printing pressure.

Second, printing adhesion

Causes of failure: 1. Sticky bags or adhesions after rewinding during printing. 2. Because the printing speed is too fast, rewind too tight. 3. The drying device is not in the right angle or fails. 4. The ink is too dry. 5. Storage stacking pressure is too large. 6. The temperature is too high and the cooling is not complete or the ink is not heat resistant. 7. Ink dilute penetration back through India. Remedy: 1. Adjust the print speed and check the drying device angle. 2. Improve the dryness of the ink (or increase the ethanol 90 + ethyl ester 10% mixed diluent). 3. When printing, there are few stacks or storage stack load is light. 4. Reduce the temperature of the workshop or warehouse (open the door to allow air convection, etc.) and replace the heat-resistant woven bag ink. 5. Add the original ink to increase its viscosity or add a small molecular weight solvent and then dilute the solvent quickly (advantageous thinner recommended by the ink factory).

Third, residual odor

Cause of failure: 1. There is a smell of raw materials in the ink. 2. The ink deteriorates. Remedy: 1. Try not to use odorless raw materials. 2. Add spices (masking agents) and prevent impurities from penetrating the ink system. 3. Ink production Pay attention to the solubility of the mixed solvent on the resin or the ink is stored in a cool and cool warehouse.

Fourth, poor film formation

Cause of failure: 1. The printing speed does not match the drying device or dryness of the ink. 2. Misuse of thinner. 3. The ink itself is not dry (such as too slow or too fast). Remedy: 1. Increase the air blow or increase (extension) the post-printing conveyor belt. 2. Adjust the printing speed (pay attention to the ink film thickness after printing). 3. Re-exchange dry fast (filming) ink. 4. Replace ink. 5. Re-dilute or add a solvent with a fast evaporation rate.

Fifth, blocking version

Failure reasons: 1. The ink is mainly dried on the printing plate to make ink transfer poor. 2. Mix in plastic or paper scraps. 3. Ink crusts. Remedy: 1. Adjust the blowing angle (not directly on the plate). 2. In addition to changing the substrate, the upper side of the printing press should be separated from the fountain ink by the base paper, plastic or film. 3. Replace the new ink or add 10% antioxidant to its ink fountain.

VI. Printout or migration

Failure reasons: 1. Ink is too thin (that is, the viscosity is too small). 2. Thin paper or plastic substrates. 3. Ink is too large. 4. Pressing too much pressure. 5. Filming is too slow. Remedy: 1. Incorporate original ink or add thickener. 2. Replace compact substrates. 3. Replace with a dry ink or add a fast solvent. 4. Adjust (reduce) ink supply. 5. The pressure should be light.

Seven, bleeding

Causes of failure: 1. The printed graphics are infiltrated with color at the edges (generally caused by dyes used in the ink). 2. The use of pigments is not properly matched or the ink has deteriorated. 3. Excessive thinner material is used, especially poor compatibility with ink and ink. Remedy: 1. Add gold oil or add coupling agent to the ink. 2. Select a solvent (such as alcohol solvent) pigment or replace it with a new one. 3. Minimize the use of thinner materials, especially solvents that are compatible with the ink.

Eight, ink film no light

Failure reasons: 1. Luster is poor. 2. Inhalation of water is distributed during the film formation. 3. The ink is rough. 4. The ink is drying too fast. 5. The ink system contains little or no matting agent. In high temperature and high humidity in summer, especially in the coastal areas, the ink absorbs the moisture in the air during the printing process and damages the oiliness, thereby reducing the gloss. Remedy: 1. Add 3% to 5% cyclohexanone or 2% to 4% ethers in the ink to resist intrusion of water molecules. 2. Re-grind or filter the ink. 3. Use slow-drying solvents to supplement the ink system. 4. Add 5% to 15% of the resin solution in the ink fountain. 5. Do not add or add less matting agent (such as wax, white carbon, etc.). 6. Replace the glossy ink or use less solvent to dilute. G (Author: Zhejiang Fukang Company) â—Ž

How to improve the quality of coated paper printing? 2007-01-07 16:40 Coated paper is an important material for the packaging and decorating printing process. The print quality of the product depends largely on the merits of the material itself and on the degree to which the operator grasps the characteristics of the paper. . In other words, in order to print coated paper products, corresponding technological measures must be taken according to the characteristics of the paper. Therefore, it is necessary to understand and understand the technical requirements for printing coated paper.

The classification of coated paper is based on the difference in the filler and calendering process, and is generally divided into single-sided light and double-sided light. Divided casein paint from the nature of the coating. So coated paper is also called coated paper. Because some domestic coated paper due to defects in the process, so easy to produce varying degrees of powder and stretching variation, in particular, single-sided coated paper is more prone to curling ills, affecting the accuracy of overprinting. If the process of printing copperplate paper is not properly handled, it is easy to produce dirty (bottom), powder, slow-drying, lack of bright star light, etc., it should pay attention to the following issues.

1. Before each batch of coated paper is put into use, a series of problems related to printability, such as smoothness, pH, absorption, drying, stretchability, and surface bond strength, shall be tested and analyzed. The characteristics of paper, to take appropriate technical measures, such as adjusting the ink viscosity, fluidity, dryness and anti-stick measures to achieve standardized scientific production, to prevent the occurrence of bad printing;

2, to put a good pad version of technology and printing pressure debugging, to ensure that the printing ink layer even and bright. Coated paper printing pressure should be obtained evenly and properly, the pressure is too heavy to easily produce powder off the bad situation, and can easily cause the dot blot imprinting ills, and increase the printing plate wear. On the contrary, it is easy to cause dot blotting is not strong, and blindly increase the ink layer to compensate for the lack of pressure caused by the layout of the flowers, so easy to produce sticky, slow dry, overprint and other adverse consequences, so the pressure of printing coated paper to be uniform Should be appropriate. Lining is made of neutral hard materials.

3, use the coated paper printing trademark, packaging products, often with a light color as the background color, made by overprinting. This improper printing of the right process, but also easy to produce some problems and affect the quality, so, in the deployment of the base color ink, it should try to use heat and light resistant ink, and dilute the best use of bright paste deployment, so you can put the background color The final printing effect is better, so as to prevent the bottom color from printing and rubbing the ink layer.

4, due to the copper plate about the surface is smooth, poor ink absorption ability, when printing the large version of the field version, should try to do "deep ink thin fluorescent. That is, the ink phase should be adjusted darker, so that the ink layer is corresponding or thin when printing. , that can meet the printing hue requirements, but also can reduce the chance of occurrence of imprinted bottom, and can prevent overlapping color printing. In addition, due to poor adhesion of the paper, the printed ink layer, sometimes easy to decolorize due to powder off, In this case, the first color can be printed with No.19 resin oil as the varnish.In order to make the laminated ink layer bright, appropriate bright oil and dry oil can be added to the ink.

5, coated paper due to a lot of paint, printing process often encounter de-powdering and print layout appear dark phenomenon. In this case, attention should be paid to checking whether the process of the plate-making process, such as the presence or absence of the pad on the printing plate, is too heavy. If the paper surface pressure is too high, it is easy to crush the coating powder on the surface of the coated paper, resulting in de-powdering and Dark spots. In addition, we should also check whether the ink viscosity is appropriate. If the printing ink layer is over-thick and sticky, it is also one of the reasons that causes the paper surface to fall off powder and accumulate the layout. In this case, you should consider applying auxiliary materials to adjust the ink. Quality, the above quality problems can be better overcome.

6, to make a good coated paper printing anti-adhesion process technology. Coated paper is weak in ink absorption, and the back is relatively smooth, so that the printing of large-printed pages or multi-color overprinting, easy to produce sticky problems, it should take measures to overcome the stick, such as the amount of light to take the first The anti-sticking agent is evenly mixed to make it liquid and then added into the ink and mixed well. When printing, a good anti-sticking effect can be obtained. However, the amount of anti-adhesive agent should be properly controlled and cannot exceed 4%, so as to avoid adverse effects such as ink emulsification, printing ink layer blooming, and ink layer glossiness decreasing.

In short, as long as the properties of printed copperplate paper are mastered and the correct printing and operating techniques are closed, not only printing efficiency can be improved, but also the printing quality can be effectively guaranteed.

Reprinted from: "Guangdong printing" 2004 3 Author: Liu poly