Htr1 (Drum Heater) Control (7075 Only) 2 - Konica Minolta 7085/FORCE 85 Service Manual

DRUM UNIT
[6] HTR1 (drum heater) Control (7075 only)
3
The drum is heated by HTR1 (drum heater). The PRCB
(printer control board) detects the drum temperature
with TH5 (drum temperature sensor) and controls
HTR1 through ACDB (AC drive board). TH5 is a sensor
that changes resistance according to the detected
temperature. Therefore, its value is converted to
voltage by DTSB (drum temperature sensor board) and
output to PRCB.
1. Operation
a. Temperature Control
HTR1 is normally maintained at 30°C and the
temperature is increased only when humidity is
high. When warming up under high humidity, the
drum is rotated after the drum temperature
reaches a specified value and then drum poten-
tial control, Dmax control, and gradation correc-
tion control are performed. When warm up com-
pletes, HTR1 is turned ON/OFF to maintain the
drum temperature constant. Under high humid-
ity, the temperature is raised to 45°C for one
minute every 30 minutes and then returned to
specified temperature to prevent dew
condensation.
b. Error detection
HTR1 is equipped with self recover type thermo-
stat to prevent abnormal increase in drum tem-
perature. The thermostat turns off at 70°C.
MODEL
7075/7085
SERVICE HANDBOOK
12VDC
5VDC
SGND
DCPS1
AC(H)
AC(C)
MANUAL REVISED EDITION
12VDC
5VDC
TH5 ANG1
DRUM TEMP
AGND
TH5 ANG2
DTSB
HTR1 CONT
PRCB
HTR1 CONT
HTR1 DRIVE
ACDB
2. Signals
a. PRCB input signal
(1) DRUM TEMP (TH5 to DTSB to PRCB)
Drum temperature signal. The relationship be-
tween drum temperature and output voltage is
linear.
b. PRCB output signal
(1) HTR1 CONT (PRCB to ACDB to HTR1)
Drum heater ON/OFF control signal
c. ACDB output signal
(1) HTR1 CONT (ACDB to HTR1)
Drum heater ON/OFF control signal
(2) HTR1 DRIVE (ACDB to HTR1)
Drum heater drive power supply line
DATE
2 - E - 4
Jan. 2002
3
TH5
HTR1
PAGE METHOD
2-E-4 REPLACEMENT