Control and measurement of doctoring angle at deformed state in doctoring apparatus for printed electronics

In printed electronics, the performance of printed devices depends on the quality of the printed patterns, or printability. It depends on the printing ink, the printing equipment, and printing conditions. Therefore, for reliable printed patterns with high printability, the printing conditions should be optimized and then maintained at constant values. Among the various printing conditions, parameters related to the doctoring process are important in gravure printing. In this study, the doctoring angle is redefined by the contact angle between the master plate and the doctor blade at the deformed state rather than the undeformed initial angle. The doctoring apparatus, capable of varying the angle of the doctor blade by controlling the position of the blade at the desired position, is developed. To estimate the doctoring angle in the deformed state without measurement from the photo image, mathematical model that calculates the doctoring angle in the deformed state using only geometric properties are derived. The doctoring angles based on the proposed mathematical model are compared with those measured from direct photo images for verifying the proposed method. In addition, the effect of the doctoring angle on the printability of the printed patterns is examined qualitatively through an experiment.