Abstract: A recorded image frame is distorted on the printing plate when image information or image data from a computer is recorded in the form of band strips, with a plurality of image elements dotted on each widthwise dotted line of the band, on a printing plate wound over a drum. The present invention permits an undistorted recording on the printing plate by an arrangement which includes a printing plate wound around a drum in the form of a right circular cylinder, an exposing assembly to record image information in the form of a band strip on the printing plate by means of light beam, a moving mechanism to move the exposing assembly in relation to the drum in the direction of the drum axis--by one band width per revolution of the drum--and a circuit to generate and incline distortion offsetting signal in a sawtoothed pattern having the cycle synchronized with that of the rotation of the drum with the initial writing position on the band as starting point.