- Hewlett-Packard Digital Sender Service Manual

Motors and fans
The scanner assembly has three motors and three fans. The motors are stepping motors, which drive
the components inside the scanner assembly. The fans cool various motors and components in the
system.
Name Purpose Type Rotation Failure detection
Scanner motor (flatbed
motor)
Drives the scanner
carriage unit
Stepping motor Varies No
Feed motor Drives the pickup, the
separation, and
registration rollers
Stepping motor Varies No
Read motor Drives the feed and
delivery rollers
Stepping motor Varies No
Scanner base fan Cools the power supply Fan Exhaust No
Scanner motor fan Cools the scanner lamp
and the CCD
Fan Intake Yes
ADF fan Cools the feed motor
and the read motor
Fan Exhaust Yes
Optical assembly
The optical assembly contains the lamp, five mirrors, a lens, and the charged coupled device (CCD).
Inverter
Scanner
CPU
Glass
Document
CCD
Scanning lamp
reflector Fourth mirror
Third mirror
Lens
First mirror
Second mirror
Fifth mirror
Controller
circuit
Figure 4-2 Scan carriage components
The scanner lamp illuminates a small strip of the document that is called the raster line. The mirrors
direct the light through the lens to the CCD. The CCD senses and records the light, creating an analog
representation of the raster line. If the ADF is being used, the document then advances in the ADF to
the next raster line. If the flatbed is being used, the carriage advances to the next raster line. This
advancing and collection process continues to the end of the sheet.
30 Chapter 4 Theory of operation ENWW