METHOD AND DEVICE FOR CONTROLLING FILM THICKNESS

PURPOSE:To enable a starting part of coating to be utilized as a product and to inhibit a push flaw from generating in the stationary part of the following material to be coated by controlling the circumferential velocity of a roll coater and/or the aperture thereof and properly keeping the film thickness of the starting part of coating. CONSTITUTION:When the joint of a material to be coated approaches a roll coater, this roll coater starts the evacuating motion and simultaneously an evacuation signal is output to a roll control changeover timing controlling function 12 from an output device 20. After this evacuation signal is inputted and an applicator roll is performed constant rotation, the controlling function 12 outputs a command to a roll control changeover circuit 13 and the circumferential velocity of the applicator roll due to the driving device 17, 18, 19 of the roll is reduced to 10-99% of the circumferential velocity at a time for stationary coating and film thickness on the applicator roll at a time for restarting the coating is regulated to 4.0-0.1 times of film thickness at the time for stationary coating. Then after the joint is passed through the roll coater, the roll coater is brought into contact with the material to be coated and simultaneously the circumferential velocity of the applicator roll is returned to the circumferential velocity at the time for stationary coating and the coating is restarted.