PURPOSE: To form dot images even without using screens, make reproduction such as medium tones, etc. easy and sure and increase image densities by chopping the picture signals such as of electrocopying apparatus or the like and exposing dot images.

CONSTITUTION: A scanning beam for forming imges is detected with a beam detector 20 and beam position detector 21, then a pulse generator 24 generates the pulses of the width corresponding to the read time of one line of a picture signal memory 23 in synchronization to the recording scanning. During this pulse period, an N-scale counter 25 to which the high frequency clocks from a clock oscillator 22 is applied generates two phases of pulse trains and the picture signals for every read line from the memory 23 are chopped through a switch 9. The signals become the image signals of phases deviated by every line and go through oscillators 1 thru 4 for generating carriers of different frequencies, modulators 5 thru 8, synthesizer 16, acousto-optic element 15, mirror 18, etc. thus scanning by the laser modulated light corresponding to the image signals is accomplished. Thereby, dot images are recorded on a photoreceptor 19 without using any halftone screen.