Color scheme common problem causes and solutions

1 The rubber roller of the printing machine is not clean

Stop the rubber roller before inking, take a piece of white cloth with solution and rub it on the rubber roller to check whether there is color on the white cloth, print dark color before printing light color, print dark color before printing bright color or rubber roller has sand The condition of the hole is most affected: clean with spot remover cream or multiple washes.

2 The thickness of the ink layer is inconsistent

Instrument measurement or visual inspection: control the amount of ink in printing

Print quality control strips measured using Spectrophotometer and visual inspection

3 The ink is not stirred evenly

Prolong the stirring time or improve the stirring method

The color development ink is not consistent with the ink tank ink

4 The tank water is not clean

Use a transparent cup to fill a glass of tank water Visual inspection: replace the tank water

Light colors and bright colors have obvious influence

5 ink oxidation

PH meter to detect acidity: Infrared thermometer to detect ink roller temperature: properly adjust water acidity, conductivity, water volume, ink roller temperature or replace brand ink

Generally, gold and silver inks are easy to oxidize, while other inks are not easy to oxidize

6 Excessive emulsification of ink

Use the emulsification Tester to check the emulsification degree of the ink: properly adjust the water acidity, conductivity, water volume, ink roller temperature or replace the brand ink

In printing, the ink is in constant contact with the dampening solution. If the ink cannot be emulsified with enough water or over-emulsified, the ink will cause adverse effects in the printing process. Generally, it has little effect on the hue, but the wet ink will generally become lighter by 3% after drying. .

 Two color development is uneven or barred

 Inspection and solution

Remark

1 Ink distribution time is insufficient or the method is wrong

Ink distribution thickness Check whether the ink is evenly attached to the metal roller and the rubber roller, increase the ink distribution time, and use the metal roller and the rubber roller to contact the ink to distribute the ink intermittently

Ink distribution requires the use of intermittent ink distribution in order to evenly distribute the ink

2 rubber roller, printing cylinder bearing damage

Disassemble the machine and inspect the bearings, if damaged

The bearings are located in Germany and Japan, and are generally not easy to damage

Three colors are false

Inspection and solution

 Remark

1 Insufficient pressure (general glossy materials)

Press the emergency stop during color development, check the ink bar width 5-6mm

Adjust the pressure of metal roller and rubber roller

2 The printing material has poor adsorption or the surface of the material is uneven (textured paper, rough paper)

Take a small amount of ink, use colorless adjustment ink (varnish) to dilute it, reduce viscosity and improve fluidity, and then develop color after increasing the color development pressure

Change the viscosity and fluidity of the ink, increase the printing pressure, and the ink type can be reserved in the backyard of the printing, which is convenient for the next color matching