Optical scanning device and optical scanning method

Abstract

An optical scanning device according to an embodiment includes a light source, a MEMS mirror, a MEMS-mirror driving unit, a control unit, and a sensor. The light source radiates a plurality of laser beams that scan a photoconductive drum. The MEMS mirror includes a reflection surface that reflects the plurality of laser beams radiated from the light source. The MEMS-mirror driving unit reciprocatingly moves the MEMS mirror. The sensor supplies a horizontal synchronization signal to the control unit by detecting the laser beam reflected on the reflection surface when the MEMS mirror reaches a predetermined position. After detecting the horizontal synchronization signal supplied from the sensor, the control unit performs the auto power control of the light amount of at least one laser beam among the plurality of laser beams.

What is claimed is: 
     
         1 . An optical scanning device comprising:
 a light source comprises a plurality of emitting units and one light receiving unit that receives a light beam from the plurality of emitting units and radiates a plurality of laser beams configured to scan a photoconductive drum;   a MEMS mirror, including a reflection surface that reflects the plurality of laser beams radiated from the light source, moves reciprocatingly by a driving unit;   a sensor configured to supply a horizontal synchronization signal by detecting a laser beam reflected on the reflection surface when the MEMS mirror reaches a predetermined position where the plurality of laser beams does not scan the photoconductive drum; and   a controller
 that performs auto power control for controlling respective light amounts of the plurality of laser beams radiated from the light source to predetermined values, 
 that controls so as to emit one of the plurality of emitting units, 
 that, based on the horizontal synchronization signal supplied from the sensor, performs a first auto power control of the light amount of at least one laser beam among the plurality of laser beams, and 
 that does not execute at least a second auto power control for the light emitting unit of the plurality of light emitting units while the one of the plurality of light emitting unit emit. 
   
     
     
         2 . The device according to  claim 1 , wherein the controller performs the auto power control of the light amounts of the plurality of laser beams after detecting the horizontal synchronization signal until detecting the horizontal synchronization signal again when the MEMS mirror turns from one direction to another direction. 
     
     
         3 . The device according to  claim 2 , wherein the controller stops the auto power control of the light amounts of the plurality of laser beams every time the controller detects the horizontal synchronization signal supplied from the sensor. 
     
     
         4 . The device according to  claim 1 , wherein the controller comprises a switch unit, a comparator, and a capacitor. 
     
     
         5 . The device according to  claim 1 , wherein the controller comprises a timing controller, a storage, a counter, a first output, and a second output. 
     
     
         6 . The device according to  claim 1 , wherein the auto power control increases the light amount of at least one laser beam among the plurality of laser beams. 
     
     
         7 . The device according to  claim 1 , wherein the auto power control decreases the light amount of at least one laser beam among the plurality of laser beams. 
     
     
         8 . The device according to  claim 1 , wherein the light source radiates at least two laser beams. 
     
     
         9 . The device according to  claim 1 , wherein the light source radiates at least four laser beams. 
     
     
         10 . The device according to  claim 1 , wherein the light source radiates at least eight laser beams. 
     
     
         11 . An optical scanning method comprising:
 moving a MEMS mirror reciprocatingly, the MEMS mirror including a reflection surface that reflects the plurality of laser beams radiated from a light source;   auto power controlling respective light amounts of the plurality of laser beams radiated from the light source to predetermined values, the light source comprising a plurality of emitting units and one light receiving unit that receives a light beam from the plurality of emitting units and radiates a plurality of laser beams configured to scan a photoconductive drum;   supplying a horizontal synchronization signal by detecting a laser beam reflected on the reflection surface when the MEMS mirror reaches a predetermined position where the plurality of laser beams does not scan the photoconductive drum;   emitting one of the plurality of emitting units;   based on the horizontal synchronization signal supplied, first auto power controlling of the light amount of at least one laser beam among the plurality of laser beams, and not executing a second auto power controlling for the light emitting unit of the plurality of light emitting units while emitting the one of the plurality of light emitting unit.   
     
     
         12 . The method according to  claim 11 , further comprising auto power controlling of the light amount of the at least one laser beam after detecting the horizontal synchronization signal until detecting the horizontal synchronization signal again when the MEMS mirror turns from one direction to another direction. 
     
     
         13 . The method according to  claim 12 , further comprising stopping the auto power controlling of the light amount of the at least one laser beam every time detecting the horizontal synchronization signal. 
     
     
         14 . The method according to  claim 11 , further comprising increasing the light amount of at least one laser beam among the plurality of laser beams. 
     
     
         15 . The method according to  claim 11 , further comprising decreasing the light amount of at least one laser beam among the plurality of laser beams. 
     
     
         16 . The method according to  claim 11 , wherein the light source radiates at least two laser beams. 
     
     
         17 . The method according to  claim 11 , wherein the light source radiates at least four laser beams. 
     
     
         18 . The method according to  claim 11 , wherein the light source radiates at least eight laser beams. 
     
     
         19 . An image forming apparatus comprising the optical scanning device according to  claim 1 . 
     
     
         20 . A multifunctional peripheral apparatus comprising the optical scanning device according to  claim 1 .