1. The coating strength of the paper is poor and the moisture content is too high;

Excessive printing pressure, fast speed and multiple color sequences; The ink has a high viscosity (the original ink has a high viscosity, or the viscosity is high during the transfer process, or the usage environment temperature is low). The particles of gold and silver ink are rough and the ink layer is thick, while the ink layer of dark ink is thick (such as overprinted black, dark blue, etc.). Improper adjustment of the dampening solution, imbalance of ink and water, and plate smudging. The downtime is too long, and the ink dries up. The rubber blanket has aged and become sticky. The drying power of the printing machine is too high. Abnormal printing conditions where the car has just been washed, the plate has just been changed, and the rubber has not been cleaned. The calendering temperature is too high, and the embossing/mounting pressure is excessive. When the environmental humidity is too high, the paper absorbs water.

2. Improvement measures for printing bubbles

Appropriately reduce the viscosity of the ink (add a de-viscosity agent or ink thinner, and in winter, use an ink constant temperature oven). If there are surface processing techniques such as oiling and calendering, it is necessary to pay attention to the addition ratio of the de-viscosity agent being less than 3%. Ensure a reasonable viscosity for gold and silver inks. Add gold toner to gold and a small amount of thinner to silver. For areas with small ink volume on the printing plate, add color strips to the trailing end to accelerate ink metabolism. If the original ink on the rubber roller has a high viscosity, clean it and replace it with new ink (including cleaning the water roller). Reduce the printing speed appropriately (to 8,000 sheets per hour);

　Before the machine stops, plate changes and formal printing, the blanket must be cleaned first. If necessary, a new blanket should be replaced. During the initial stage of printing, the speed of the vehicle should be appropriately controlled and not too high. Wait until the ink and water reach a balance before increasing the speed. Under humid weather conditions such as rainy days and the return of the south wind, paper should be wrapped in film for storage. For orders with high printing difficulty, such as multi-color, ultra-high-speed, high-pressure light and other processes, it is recommended to give priority to choosing paper with sufficient grammage (not high porosity), and if necessary, select paper types with better interlayer strength.