Chapter 55-15.1 Construction5.1.1 Outline 0006-2874The laser scanner unit consists of the following major components:- laser unit, which serves as the source of laser beam.- laser scanner motor, equipped with a 4-face mirror for laser scanning.- laser driver/BD PCB used to detect laser beam or to control emission of laser beam.The laser beam generated by the laser unit based on the signals from the DC controller PCB moves through thecollimator lens (inside the laser unit) and the cylindrical lens to reach a 4-face polygon mirror rotating at a constantspeed.When reflected by the 4-face polygon mirror, the laser beam moves through the imaging lens, and is bent by thereflecting mirror to reach the photosensitive drum. At this time, the laser beam also is directed to the BD circuit ofthe laser driver/BD PCB.As the 4-face polygon mirror rotates at a constant speed, the laser beam scans the surface of the photosensitive drumat a constant speed, thereby removing charges and forming static images.F-5-1Reflecting mirrorLaser driver/BD PCB• copy image data• print image data• fax image data (if equipped with fax functions)Cylindrical lens4-face mirrorDC controller PCBLaser driver blockPhotosensitive drumLaser scanner motorLaser unitBD blockImaging lensLaser beamdetection signal(BDI*)Image signal(VDO,VDO*)Laser scannermotor drive signalLaser drivercontrol signalCommunicationcontrolHorizontalsync signalImage processor PCB
