Apparatus For And Method Of Forming Images With Oscillation Mirror

Abstract

An image forming method which generates a video signal corresponding to an image forming command based on a video clock signal, modulates a light beam according to the video signal, and scans the modulated light beam along a main scanning direction by means of an oscillation mirror which resonates based on a drive signal, so as to form a latent image in an effective image region of a latent image carrier, the method includes: synchronizing the drive signal with the video clock signal to synchronize a detection signal with the video clock signal, the detection signal being output from a detector which detect the light beam scanned in the main scanning direction in a region away from an effective scan region which corresponds to the effective image region; controlling a resonant frequency of the oscillation mirror based on the detection signal so that the resonant frequency of the oscillation mirror almost coincides with the frequency of the drive signal; and adjusting a position, at which the latent image is written over the latent image carrier, is adjusted by adjusting output timing of the video signal based on the detection signal from the detector.

1 - 6 . (canceled) 
   
   
       7 . An image forming method, comprising:
 oscillating an oscillation mirror based on a drive signal synchronized with a video clock signal;   detecting a light beam, which is scanned in a predetermined direction by means of the oscillation mirror, with a detector to output a detection signal;   making the oscillation mirror resonate by controlling a resonant frequency of the oscillation mirror based on the detection signal so that the resonant frequency of the oscillation mirror almost coincides with the frequency of the drive signal;   modulating a light beam according to a video signal which is generated based on the video clock signal to obtain a modulated light beam; and   scanning the modulated light beam in the predetermined direction by means of the oscillation mirror which resonantly oscillates, so as to form an image on an image carrier.   
   
   
       8 . The image forming method of  claim 7 , wherein a pulse width of the video signal is fixed to correspond to one pixel of the image. 
   
   
       9 . The image forming method of  claim 7 , wherein output timing of the video signal is adjusted based on the detection signal from the detector after the completion of controlling the resonant frequency, whereby a position, at which the image is written over the image carrier, is adjusted. 
   
   
       10 . The image forming method of  claim 9 , wherein the image writing starts immediately after the completion of controlling the resonant frequency. 
   
   
       11 . An image forming apparatus, comprising:
 an image carrier;   a light source that emits a light beam;   an oscillation mirror that scans the light beam in a predetermined direction;   a mirror driver that drives the oscillation mirror;   a mirror drive controlling section that controls oscillation operation of the oscillation mirror by applying a drive signal which is synchronized with a video clock signal, to the mirror driver;   a detector that detects the light beam scanned in the predetermined direction by means of the oscillation mirror and outputs a detection signal;   a resonant frequency adjuster that adjusts a resonant frequency of the oscillation mirror;   a frequency controlling section that controls the resonant frequency adjuster based on the detection signal which is output from the detector, thereby making the resonant frequency of the oscillation mirror almost coincide with a frequency of the drive signal; and   controller that generates a video signal based on the video clock signal, modulates a light beam according to the video signal and scans the modulated light beam in the predetermined direction by means of the oscillation mirror which resonantly oscillate, so as to form an image on the image carrier.   
   
   
       12 . The image forming apparatus of  claim 11 , further comprising a writing position adjuster that adjusts output timing of the video signal based on the detection signal from the detector after the completion of controlling the resonant frequency, so as to adjust a position at which the image is written over the image carrier.