When printing BOPP color composite paper, how to ensure the color uniformity of the pattern?

When printing BOPP (Biaxially stretched polypropylene) color synthetic paper, ensuring the color uniformity of the pattern is a key step, which directly affects the quality and visual effect of the final product. Here are some specific ways and suggestions to ensure color uniformity:

1. Preliminary preparation

(1) Paper selection and treatment

Paper consistency: Select the same batch of BOPP color synthetic paper with the same whiteness, smoothness and ink absorption ability to avoid uneven color caused by paper differences.

Humidification treatment: Ensure that the water content of the paper is uniform to avoid the generation of static electricity, because static electricity may affect the transfer and uniformity of the ink.

(2) ink selection and allocation

Ink quality: Select ink with stable quality and strong coloring power to ensure the color consistency of different batches of ink.

Ink allocation: Avoid mixing ink with a large proportion to prevent the stratification of ink. For prints with rich color levels, ink with strong coloring power should be selected.

2. Adjust the device

(1) Printing pressure adjustment

The proper printing pressure is the key to ensure the uniform transfer of ink. If the pressure is too low, the imprint will be empty and incomplete, while if the pressure is too high, the dot will be enlarged and the imprint will be blurred. Therefore, it is necessary to adjust the printing pressure according to the characteristics of the paper and ink, and maintain the consistency of the pressure throughout the printing process.

(2) Ink delivery device and ink balance

Check and adjust the ink delivery device to ensure stable and even ink supply.

In lithography, it is very important to control the balance of ink and wash. Too much or too little moisture will directly affect the printing quality and color uniformity.

(3) Equipment cleaning and maintenance

Regularly clean the printing equipment, especially the parts in direct contact with ink and paper, to prevent impurities such as oil, dust and other impurities from affecting the color uniformity.

3. Printing process control

(1) Color sequence arrangement

According to the nature of the original picture, the characteristics of ink and paper and the structural characteristics of the printing press, the color order is reasonably arranged. Color sequence inconsistency may lead to color deviation, so the color sequence between the proof and the print should be unified.

(2) Real-time monitoring

During the printing process, the quality of the printed matter is monitored in real time, especially the color uniformity. Once you find uneven color or other quality problems, you should immediately stop to check and adjust.

4. Post-processing and inspection

(1) Finished product inspection

Complete inspection of the printed finished product to ensure uniform color, clear pattern and no defects.

(2) Storage and protection

The optical properties of BOPP films will decline with the extension of inventory time, so it is recommended to control the inventory period within 3 to 4 months. At the same time, pay attention to the storage environment of the finished product, avoid moisture, heat or direct sunlight.

In summary, to ensure the color uniformity of BOPP color synthetic paper printing patterns, it is necessary to start from many aspects such as preliminary preparation, equipment adjustment, printing process control, post-processing and inspection. Through fine operation and strict quality control, the quality and visual effect of printed matter can be effectively improved.