What problems may occur during the process of printing copperplate paper adhesive labels?

During the process of printing copperplate paper adhesive labels, the following issues may occur:

1、 Printing quality issues

Rubbing dirt on the back:

Problem description: The ink on the adhesive label paper will print on the back of another printing paper, causing the back to get dirty.

Solution: Install a powder spraying device at the receiving part of the printing equipment to refine the tiny particles of calcium bicarbonate between the printed sheets. Accelerating the drying speed of ink, reducing the height of paper stacking, and placing paper with good ink absorption between sheets can also help suppress the phenomenon of smudging.

Transparent printing:

Problem description: The front imprint can be seen on the back of the adhesive label paper.

Solution: Use paper with high tightness for printing, or increase the viscosity of ink and reduce printing pressure appropriately to avoid ink penetration.

Feimo:

Problem description: Small droplets formed by ink splashing into the air during the printing process, also known as ink mist, are the most common malfunction of adhesive label paper in high-speed rotary relief printing machines.

Solution: Increase the humidity in the printing workshop and use printing ink with good conductivity, such as water-based ink, to alleviate ink flying phenomenon.

Ink layer is not dry or prone to falling off:

Problem description: The ink layer on the surface of the printed label does not dry, dries slowly, or the ink layer falls off as soon as it is wiped off.

Solution: Adopt the method of deep ink thin printing to reduce the thickness of the ink layer, use specialized ink that dries quickly, add matching desiccants, extend the drying or curing time of printed materials, and increase room temperature and appropriate ventilation to accelerate the ink drying speed.

2、 Material compatibility issues

Poor adhesion of ink:

Problem description: The ink layer on the surface of the film has poor adhesion and is prone to ink peeling.

Solution: Improve the surface tension of the printing material, requiring a surface tension value of at least 38 dynes/centimeter. Install a corona device to increase the surface tension of the film, using specialized ink and matching additives that match the printing material. Increase drying or curing power, reduce machine operating speed, and increase drying time. The printing ink layer should be as thin as possible, the ink volume should be as small as possible, and if necessary, single color printing can be repeated multiple times. UV coating is applied after printing to protect the printing ink layer.

3、 Static electricity issues

Electrostatic reaction:

Problem description: In the printing process, adhesive label paper is difficult to separate, the paper on the receiving table is not neatly collected, or the paper on the feeding table is skewed, resulting in inaccurate overprinting, which may be caused by electrostatic reactions.

Solution: Install a static eliminator on the printing machine to ionize the air around the printing equipment and neutralize the positive and negative static electricity on the paper. Spraying appropriate water mist around the printing equipment or above the back of the impression cylinder can increase the humidity in the printing production workshop and also help remove static electricity.

4、 Operation and equipment issues

Inaccurate overprinting:

Problem description: Due to unstable paper size, paper glue leakage, cutting and positioning errors, paper creases, electrostatic adsorption, plate stretching deformation, inconsistent rubber cloth lining, etc., the overprinting is inaccurate.

Solution: Control the temperature in the printing workshop at 20-22 degrees Celsius and the relative humidity at 50%. Use non permeable and qualified adhesive materials to improve the situation of adhesive leakage. Improve paper cutting accuracy, correctly sort paper, and avoid excessive deformation. Install static eliminators and humidifiers to control workshop temperature and humidity. Ensure consistent tightness of the upper version, lining, and rubber cloth through sampling. Replace the rubber blanket or lining of the entire unit to improve the accuracy of the printing machine.

In summary, there may be various problems encountered during the process of printing copperplate paper adhesive labels, and corresponding solutions need to be taken based on specific situations. By strictly controlling the printing quality, selecting suitable inks and materials, solving static electricity problems, and optimizing operation and equipment settings, the smooth progress of the printing process and stable improvement of label quality can be ensured.