OPTICAL IMAGING APPARATUS AND METHOD

摘要

A scanned light beam imaging apparatus includes a laser (50) providing a light beam (51) to an acousto-optic modulator (52) which deflects an unmodulated beam (55) away from a knife edge (56) in accordance with an input signal (53). The deflected beam (62) is projected through a beam expanding lens (63) to a beam deflector (64) which projects the beam through an imaging lens (66) onto a photoconductor surface (11) on a rotating drum (10) so as to scan along a line (70). The signal (53) is derived from an amplitude modulation circuit (61). A random motion modulation is applied to the deflected beam by a frequency modulation circuit (80) which supplies a frequency modulation carrier signal to input (81) of the amplitude modulation circuit (61). The frequency modulation circuit (80) includes a source of random modulation of amplitude and/or frequency. The deflected beam (62) is randomly moved orthogonally to the scan direction to break up any unscanned or overscanned interstices between adjacent linear scans to render the interstices nearly invisible.