Let's talk about the air knife coater again. 

The working principle of the air knife coater is similar to the knife coater, the difference is that the knife coater uses a steel knife to coat and level off. 

The air knife coater uses the air ejected under pressure to adjust the coating amount and smooth the coating layer, which is called air knife coating for short. 

The advantage of air knife coating is that it can get a thicker coating amount, the coating layer is relatively uniform, and it is not easy to break the paper during coating. It is especially suitable for the coating of pressure-sensitive coatings; but because the scraper of this coating machine It is an invisible air knife. To make the coating uniform and smooth, the coating is required to have a corresponding concentration and sharpness. 

The disadvantage is that it cannot be coated with high solid content, and the air knife is easy to be partially blocked by the dry coating, causing the coating trace.

Finally, the roll coater uses a coating roller to apply coating to the paper surface, and the coating inside the machine is mainly based on this type of coater. 

The amount of coating can be adjusted by measuring the pressure between the rollers. 

If the pressure is strengthened, the passing amount of the paint will decrease, and the coating amount will also decrease. 

The advantage of the roll-type double-sided coating machine is that it is simple in structure and can perform double-sided coating at the same time. 

As an in-machine coating machine, it has a more suitable coating speed and is not easy to generate coating streaks. 

The disadvantage is that it is not easy to obtain the coating thickness of the air knife coater, nor can it obtain the smoothness and gloss of the knife coater.