One, the color is too dark
1. Phenomenon: The color of the printed product is different from that of the original product and is deeper than it is.
2. Reasons: (1) High ink viscosity. (2) The number of anilox rollers is low and the amount of ink stored is large. (3) High color content, high ink color saturation. (4) Problems with platemaking (websites). (5) The choice of substrates cannot be adapted. (6) The printing shop is not constant temperature and humidity, affecting the use of ink.
3. Solution: (1) Reasonably add thinner to reduce viscosity. The amount of diluent added not only affects the viscosity of the ink, but also affects the print density. (2) Reasonably change or increase the number of anilox roller lines. (3) Add dilute agent. (4) According to different substrates, the calibration value of the dot is generally increased or decreased. (5) The substrate is not the same as when it was actually produced. The surface of the substrate is smooth, there is no pit, the ink cannot be absorbed, and the ink layer remaining on the surface is thicker. Relatively high reflection density, prints darker. (6) Maintain constant temperature and humidity to ensure viscosity.
Second, stripes or spots
1. Phenomenon: There are spots of unwanted light or dark colors on the roll.
2. Reasons: (1) The anilox roller does not carry ink locally. (2) The printing plate is uneven and the ink is uneven. (3) Bubbles form during printing; ink splashes on the printed material. (4) The ink is too thin. (5) Poor ink viscosity. (6) The thickness of the substrate is uneven. (7) The embossing roller is damaged or dirty.
3. Solution: (1) Clean the anilox roller or check the amount of ink on the ink tray. If not enough, add more. (2) Check the printing plate, from the ink to the ink supply to check for uneven reasons. (3) Add antifoaming agent to the ink. (4) Check the ink fountain cover, ink tube connector, and ink tank to prevent excessive ink flow and loss. (5) Add new ink. (6) Increase the stickiness and change the thin and uniform substrate. (7) Check the impression cylinder, replace it, and remove dirt.
Third, the ink is too weak or too thin and shallow
1. Phenomenon: The ink color intensity is too low and light. The ink saturation is not enough and the color density is insufficient.
2. Reasons: (1) too much solvent or too low viscosity, affect the ability to drive the pigment. (2) The anilox ink transfer roller is worn or uncleaned, and there is a hole blocking phenomenon. (3) Settling of the ink occurs unevenly, the coloring power is insufficient, and the pigment is dispersed. (4) The plate is not suitable for soft and hard, the number of anilox roller lines is too high, and the amount of ink is not enough. (5) The ink roller is not adjusted properly and the printing pressure is too small. (6) In the process of ink transfer, improper use of ink transfer roller. (7) In water-based inks, volatile compounds are excessive and the ink layer is thin. (8) The printability of the substrate is poor. (9) Too much ink dilute agent. (10) Insufficient ink viscosity causes poor transfer.
3. Solution: (1) Add new ink and adjust to an appropriate viscosity. (2) Replace the old roller with a new or re-engraved anilox roller. (3) Stir the ink taken out of the tub thoroughly before adding to the ink fountain. (4) Replace the appropriate ones. (5) Reduce the number of reticulate lines and adjust the ink roller so that excess ink is attached to the roller to increase the pressure. (6) Replace the ink transfer roller that matches the material being printed (use low hardness). (7) More than 3% of volatile compounds. (8) Select the substrate according to the print product requirements. When the paper with strong ink absorption property is selected, the ink layer remaining on the surface of the paper during printing is thin, so the reflection density is low, and the printing product is lighter in color. It is generally believed that the thickness of the plain ink layer is 1-2 μm, the thickness of the flexo ink layer is 2-5 μm, and the thickness of the gravure ink layer is 10 μm, which can meet the printing requirements. (9) Re-adjust ink. (10) Reasonably adjust the ink viscosity.
Fourth, the outline of the printing process is not clear
1. Phenomenon: The edges of the pattern are blurred.
2. Reasons; (1) Printing pressure is too high. (2) The viscosity of the ink is too low. (3) Poor plate quality. (4) The main color ink contains other color inks. (5) Printing plate ink drying too fast. (6) Machine speed is too low at room temperature.
3. Solution: (1) Use proper pressure and correct double-sided tape. (2) Increase the ink viscosity. (3) Remaking plate. (4) Replace with new ink. (5) Reasonable adjustments. (6) Maintain constant temperature and humidity, increase speed.