Canon i-SENSYS MF229dw Service Manual

Canon i-SENSYS MF229dw Service Manual Manual pdf 35 page image

22 2-112-11Technical Overview > Laser Exposure System > Overview > OverviewTechnical Overview > Laser Exposure System > Overview > OverviewLaser Exposure SystemOverview■ OverviewThe laser exposure system forms static latent images on the photosensitive drum accordingto the VIDEO signals sent from the main controller, and is comprised of the laser driver andscanner motor, etc. These are controlled by the engine controller. The following is the outline.Laser unitScanner motor unitFour-faced mirrorCylindrical lensPhotosensitive drumEngine ControllerBD INPUT signalVIDEO signalLASER CONTROL signalSCANNER MOTORSPEED CONTROL signalMain controllerFocus lensBD sensorCollimatorlensF-2-13The operational sequence of the laser scanner unit is described below.1) When the Main controller sends print instruction command, the Engine controller rotatesthe Four-faced mirror, causing the Scanner motor to rotate.2) When the Scanner motor starts to rotate, the Engine controller emits the laser forciblyusing the Laser control signal, causing the Engine controller to start rotation control for theScanner motor.3) The Engine controller controls to keep a constant speed of rotation of the Scanner motorusing the Scanner motor speed control signal.4) After the rotation speed of the Scanner motor reaches its target, the Main controller sendsVIDEO signals to the Laser driver PCB.5) The Laser driver emits laser diode according to these signals.6) The laser beam passes through the collimator lens and the cylindrical lens and enters theFour-faced mirror rotating at a constant speed.7) The laser beam reflected by the Four-faced mirror is focused on the Photosensitive drumvia the image-forming lens at the front of the Four-faced mirror.8) When the Four-faced mirror rotates at a constant speed, the laser beam on thePhotosensitive drum is scanned on the Photosensitive drum at a constant speed.9) When the Photosensitive drum rotates at a constant speed and the laser beam is scannedon the Photosensitive drum at a constant speed, latent images are formed on thePhotosensitive drum.