Xerox Phaser 4620 Service Manual page 386

Never remove the cover from a Laser Assembly for any reason - contamination may result.
The Laser Unit consists of four components: the laser diode (LD) Assembly, the scanner
assembly, lenses and mirrors, and the start of scan (SOS) board.
Table 2 Laser Assembly Components
Component Function
Laser Diode Assembly Produces two laser beams that are turned on and off according to
the print data signal.
Scanner Assembly Consists of a faceted polygonal mirror mounted on the shaft of the
scanner motor that reflects the beams to the drum surface through
lenses and mirrors, to scan the beams across the drum.
Start of Scan Board When the laser beams strike the sensor on the SOS board, the
signal generated indicates the initial position of the scan. The ini-
tial position where a scan is started on each line is detected.
Scanner Motor control is performed according to the mode of operation as shown below.
Table 3 Scanner Motor Operational Modes
Operational Mode Laser Power On/Off
Standby Mode Always Off
Print Mode Turns On upon receiving the signal from the controller, and turns
Off after a preset time has passed from the end of printing. Also
turns Off if a print command is not received within 30 seconds
from the reception of the signal.
Sleep Mode Always Off
Principles of Operation
Xerographics
CAUTION Fuser
The Fuser, using a combination of heat and pressure, bonds the toner to the media. As a CRU,
the Fuser is replaced as a unit. However, spares are available for the Heat Lamp, Heat and
Pressure Rollers, and Fuser Drive Gear.
The Fuser receives its drive from the Fuser Drive Assembly. After the toner image is trans-
ferred to the media, the media passes through the Fuser. The Pressure Roller is pressed
against the Heat Roller to melt the toner and bond the image to the media.
5/2011
8-10
Figure 7 Fuser
Revision - Xerox Internal Use Only
Phaser 4600/4620 Printer Service Manual