Abstract: A blank feeder for feeding blanks. It has a feed table on which a plurality of blanks are stacked, a suction unit provided under the table to suck the lowermost one of the stack downward, a motor-driven first feed rolls mounted in the suction unit and adapted to feed the lowermost blank in contact therewith, and second feed rolls located downstream of the first feed rolls and adapted to be driven at a constant speed. The first feed rolls are accelerated from zero speed to the speed of the second feed rolls before the front end of the blank reaches the second rolls, then driven synchronized with the second feed rolls, and decelerated to zero speed again by the time the next cycle begins. A kicker for pushing out the blank may be provided. The kicker is moved forward so as to be synchronized with the second feed rolls before the front end of the blank reaches the second feed rolls. Once synchronized, this state is maintained until the rear end of the blank gets off from the kicker.

Abstract: A device for detecting any defects in single faced corrugated fiberboard while it is running. A light is irradiated to the corrugated surface of the fiberboard and the striped image is scanned by an image pick-up unit and the picture signal is converted to binary-coded signal to discriminate the number of stripes or corrugations. The number is counted by a counter and compared with a normal number by a microcoputer. If there is too large a difference between them, the scanned part is judged as defective. This device can detect any defects in a running web at a sufficiently high speed to follow the line speed of a corrugating machine.