Oki OKIPAGE 12i Series, Service Handbook

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(1) Image Drum Unit
The image drum unit consists of a sensitive drum, a charger, and a developer. The unit forms
a toner image on the sensitive drum, using a electrostatic latent image formed by the LED
head.
(2) Registration Motor
The registration motor is a pulse motor of 48 steps/rotation with two-phase excitement by the
signal from the main control board. It drives the hopping and registration rollers via two one-
way clutches according to the direction of rotation.
(3) Main (Drum) Motor
The main or drum motor is a pulse motor of 48 steps/rotation with two-phase excitement by
the signal from the main control board and is the main motor of this mechanism.
(4) LED Head
Image data for each dot line from the main control board is received by the shift register and
latch register. The 4992 LED's are driven to radiate the image data on the image drum.
(5) Fuser
The fuser consists of a heater, a heat roller, a thermistor and a thermostat.
The AC voltage from the power supply/sensor board is applied to the heater controlled by
the HEATON signal from the main control board. This AC voltage heats the heater. The main
control board monitors the heat roller temperature via the thermistor, and regulates the
heater roller to keep it at a designated temperature in the menu, depending on the thickness
of the paper (tray 1&2: light=165
°
C, medium light=170
°
C, medium=175
°
C, medium heavy
and heavy=195
°
C; manual feeding and power envelope feeder: light=175
°
C, medium
light=180
°
C, medium=185
°
C, medium heavy=190
°
C, heavy=195
°
C, transparency = 170
°
C)
by connecting or disconnecting the AC voltage supply to the heater.
When an abnormal rise of the heater roller temperature takes place, the thermostat of the
heater voltage supply circuit becomes active and forcibly cuts the AC voltage supply.
The temperature setting of the fuser can be changed through operator panel setting.