HP LaserJet Pro M201n - Page 38

Laser/scanner system
The laser/scanner system receives VIDEO signals from the ECU and formatter and converts the signals into
latent images on the photosensitive drum.
The main components of the laser/scanner are the laser unit and the scanner motor unit. The DC controller
sends signals to the laser/scanner to control the functions of these components.
Figure 1-13 Laser/scanner system
Formatter
DC controlle r
BDI signal VIDEO signal LASER CONTROL signal
SCANNER MOTOR CONTROL signal
Engine controller
Photosensitive drum
Scanning mirror
BD sensor
Laser unit
Scanner motor unit
Laser failure detection
The DC controller determines an optical unit failure and notifies the formatter, if the laser/scanner
encounters the following conditions:
22 Chapter 1 Theory of operation ENWW