Drive And Photographics - Star Micronics LS-5 SERIES Technical Manual

THEORY OF OPERATION

3-4. Drive and Photographics

[1] Drive Assembly:
Comprises a main motor and gears to transmit its drive, providing mechanical drive by rotation of the main motor.
[2] ROS Assembly (ROS: Raster Output Scanner):
Comprises an LD assembly, scanner assembly, SOS PCB, lens, mirror and window. The items related to the ROS
assembly are referred to as ROS.
• LD Assembly (LD: Laser Diode):
Converts electric signals into a laser beam, emitting light.
Power of a laser diode (LD power) is controlled to be constant through the monitor circuit.
• Scanner Assembly:
A polygon mirror with six specular surfaces is mounted on the scanner motor to rotate at a constant speed. The
rotation of the polygon mirror causes angles of incidence and reflection of a laser beam to change, one surface of
the polygon mirror scanning one line in direction of the drum axis.
A laser beam reflected by the polygon mirror is irradiated on the drum surface via the lens, mirror and window.
• SOS PCB (SOS: Start Of Scan):
The irradiation of a laser beam on the SOS sensor causes the laser beam to be converted into an electric signal(SOS
signal), thereby detecting the initial scanning location of one line.
[3] CRU Sensor PCB (CRU: Customer Replaceable Unit):
Comprises a CRU switch and LD switches which are turned ON and OFF by the CRU actuator assembly, the former
detecting the presence of the EPX toner cartridge and the latter, in series with the circuit emitting a laser beam,
securing the safety for a laser beam.
[4] EPX Toner Cartridge (EP: Electrical Photographics):
Comprises a drum, BCR, magnetic roll, CM blade and cleaning blade.
• Drum:
Comprises an aluminum cylinder on which an OPC (Organic Photo Conductor) sensitive material with photo-
conductivity (a quality to retain the electrical charge in the darkness and move it to the earth by light) is deposited,
producing a printed image according to the potential difference (electrostatic latent image) of the surface.
• BCR (Bias Charge Roll):
Enables the drum surface to be electrically charged uniformly.
• Magnetic Roll:
Supplies toner to the drum for developing an electrostatic latent image on the drum surface.
• CM Blade (CM: Charge Metal):
Not only makes homogeneous the amount of toner on the magnetic roll surface but gives toner the electrical charge
by means of friction.
• Cleaning Blade:
Scratches off residual toner on the post-transfer drum surface, cleaning it.
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