Abstract: A perforating rule for perforating paper and plastic including a shank portion having substantially planar side surfaces parallel to a central plane therebetween, a cutting portion having a V-shaped cross-section with the narrower end of the V providing a cutting edge, the cutting portion having portions separated by a plurality of notches extending inwardly from the cutting edge toward the shank portion, and an intermediate portion interconnecting the shank and cutting portions having opposite side surfaces extending from the shank portion to the cutting portion. The thickness of the rule at about 0.024 inch from the cutting edge is about 0.014 inches, the notches have a width in the direction of the length of the rule of about 0.007 inches and a depth of about 0.025 inches, and the portions of the cutting portion have a width in the direction of the length of the rule greater than the width of the notches.

Abstract: In the calligraphic printing apparatus disclosed herein, a writing stylus is carried by a flexing suspension including a pair of generally orthogonal arms, each arm being driven by a respective servo system which responds to stored data representing characters to be written. The naturally arcuate path defined by each arm is substantially linearized by mixing into the drive signal for each servo system a compensating signal which is a function of the absolute value of the position signal controlling the servo system for the other arm.