Weak Lens; Beam Compressor; Spin Motor Module - AGFA Avantra 36/44 Service Manual

Avantra 36/44 Service Manual

2.11.5 Weak Lens

The weak lens, which is a long focal length lens, moves along the optical axis of the
SGM to provide for a system level focus adjustment. It mounts between the polarizer
and the spot forming lens. A small motor and screw mechanism translates the lens
to provide the proper focal length over the entire range of media thicknesses (4 - 12
mils) as well as a system level fine focus adjustment. A motion of 20 mils. of this lens
shifts system focus by approximately 1 mil.
Every system has the weak lens mechanical components installed. They provide for
the system level focus adjustment. The software to automatically adjust focus for dif-
ferent media thicknesses is optional.

2.11.6 Beam Compressor

The beam compressor mechanisms consist of a lens, sensor, and motor. The lens is
moved in front of the laser diode only at 1200 DPI. This occurs because of the
larger dot (20 microns), which requires more laser output at 1200 DPI.

2.12 Spin Motor Module

The spin motor module is a field replaceable unit that mounts to the carriage assem-
bly. The spin motor module provides the high-speed deflection of the focused laser
spot along the curved inside circumference of the image plane (drum).
The module consists of a high-speed spin motor on which a mirror and encoder are
mounted and balanced. Figure 2-8 illustrates the spin motor module.
Figure 2-8 Spin motor module.
–Spin motor. –Mirror. –Spin motor mount. –Encoder.
2-18 Functional Analysis