EVALUATION METHOD AND DEVICE FOR FILM THICKNESS UNIFORMITY AND AUTOMATIC CONTROL METHOD AND DEVICE FOR FILM THICKNESS

摘要

PURPOSE:To enable the evaluation of film thickness uniformity by projecting light for plural positions in the widthwise direction of a film roll, measuring the quantity of light reflected from the film roll and evaluating a difference in the quantity of light reflected from the plural positions. CONSTITUTION:A film roll 22 upon completion of a winding process, is shifted to a position adjacent to a thickness uniformity detecting device 24, a pneumatic cylinder 34 operates to make a support member 32 come near the film roll 22 and this support member 32 stops moving at the position where a stopper 40 comes in contact with the film roll 22. In this state, a plurality of photoelectric sensors 38 operate to project the predetermined light to the film roll 22 and receive light reflected therefrom. When the thickness of a film taken up with the aforesaid roll 22 is not uniform in a widthwise direction, air is entrapped in the portion of small thickness, thereby generating an emulsive and opaque condition. The quantity of reflected light at the aforesaid portion, therefore, increases and the sensor 38 is turned on, thereby enabling the sensing of a thin film portion. Also, the signal of the sensor 38 is inputted to a controller and the uniformity of film thickness is thereby evaluated.