Method for applying a product by roller and application system

A system for applying a product by roller on a substrate (112), comprising:

• an application head (111, 111′) comprising an application roller;
• a transport device (124) configured to transport the substrate (112) horizontally with respect to the application head (111, 111′);
• an actuator (113, 113′) configured to move the application head between a lowered position and a raised position;
• a position detector (115) configured to detect a position of the substrate (112) with respect to the application head (111, 111′);
• and
• a microprocessor (116) configured to command a movement of the application head (111, 111′) immediately from a lowered position of the application head (111, 111′) in which the application roller (122, 122′) applies product in a predetermined position of the surface of the substrate, to a raised position of the application head (111, 111′) in which the application roller (122, 122′) does not apply product, or moving the application head immediately from a raised position of the application head to a lowered position;
• the microprocessor (116) further configured to receive from the position detector (115) a signal for detecting the position of the substrate (112) and sending an actuation signal to the actuator (113, 113′) in order to move the application head (111, 111′) in the predetermined position of the substrate (112),
• wherein the actuator (113, 113′) comprises a connecting rod and crank, wherein the rod is configured to move the application head (111, 111′) when the crank is turned by a motor, corresponding to a complete rotation movement of an eccentric shaft of the connecting rod and crank.