The roll coater is a device that applies a certain amount of paint to a planar material like aluminum coil using more than one set of rotary rolls. Its existence greatly improves the popularity of color coated aluminum coil which serves as a material replacing colored steel in construction. The thickness of the coating can be adjusted by changing the pressure between the two rolls. Typical types include roll type, press roll type, forward and reverse roll type etc.

A typical structure for color coated aluminum coil consists of devices for coating, supporting&rotating and driving. The coating device is also referred to as a coating head, usually composed of paint-fetching rolls, coating rolls and paint discs. This structure is called double roller type. The paint-fetching roller obtains paints from the disc, and then sends them to the coating roll which make paints on to the passing aluminum roll. A more advanced coating device is three-roller coater. An extra adjusting roll is added to adjust the gap between the paint-fetching roller and the coating roller. In case of need for rapid exchange of paints and coating rollers, two coating heads can be adopted. The rotating&supporting device consists of rolls for rotating, supporting and head covering. The steering roller steers the web at 180 ° C to bring the web into the supporting roller at an appropriate angle; the support roller is coated, the support web is subjected to front coating; the top roller is between the support roller and the back coating head The coil material acts as a top support, and the amount of coating on the back side of the coil can be adjusted by adjusting the distance of the top support by the adjusting mechanism. When the machine stops and the seam of the coil passes, the aluminium coil is lifted off the back coating roller by means of an automatic adjusting device. Protect the applicator roller from damage. The driving device of the roll coater is divided into two modes: collective drive and single roll drive. Collective driving means that all the rollers of the roll coater are driven by one motor, and this driving method is not easy to change the technical parameters. The single-roller drive is equipped with a dedicated DC motor for each roller, which can change the direction of rotation and the speed of rotation arbitrarily, and easily change the technical parameters of the process. It’s through these devices that plain aluminium rolls become color coated aluminum coil for various applications.