Discharge Unit; Fuser Unit - Oki LP-1040 Maintenance Manual

12.5.8

Discharge Unit

After the transfer process, the residual potential on the photoconductor surface is at an uneven
value due to the different functions of each process invoked. If left in this state, past latent
images could appear on the image in subsequent processes. Therefore, it is necessary to
perform a discharge to equalize the residual potential on the photoconductor surface before
applying the primary charge.
This Printer uses a light-based LED discharge method.
(1) Discharge unit function
(a) Residual potential removal function
A LED emits light, removing the residual potential on the photoconductor drum surface.
(2) LED discharge outline
Normally, a red LED is used. The amount of light emitted by the LED is adjusted according to
the sensitivity of the drum. Therefore, it is necessary to perform PWM control on the number of
LEDs and their drive voltage.
Discharging light is shined on the surface while performing a charge. Then, the drum is
checked for a stable charge voltage to determine the correct LED luminescence.
12.5.9

Fuser Unit

Fusing is the process of attaching the toner to the surface of the paper.
This Printer uses a heat roller method due to its high image quality and how well it fuses.
(1) Fuser unit functions
(a) Heating function
A halogen heater is used to heat up the heat roller.
(b) Temperature detection control function
Temperature detection range -- 160 to 190 degrees Celsius
(Method: Thermistor temperature detection, heater On/Off)
Overheat detection -- 200 degrees Celsius (Method: thermistor)
Overheat protection -- Overheat protection temperature fuse
(c) Power save function
(d) Paper transport function
(e) Paper pressure/nip release function
Releases the fuser roller's nip with the fuser unit's open/close action.
(f) Cooling airflow
Provides ventilation to the side of the Printer using a blower.
(g) Offset protection
Uses a teflon roller to protect against toner offset.
(h) Heat retainment function
Chapter 12 Printer Operation Guide
12-19