KONICA 1312 Service Manual ech7
Chapter 7 Electricity
7-1. Main control circuits ................................... 7-1
7-1-1. Toner density control .............................. 7-1
7-1-2. Fusing temperature control .................... 7-2
7-1-3. JAM detection .......................................... 7-3
7-1-4. Safety circuit ............................................ 7-4
7-2. Timing chart ................................................ 7-5
7-2-1. A4, TWO COPIES, CASSETTE PAPER
FEED (UPPER) .......................................... 7-5
7-2-2. A4, TWO COPIES, CASSETTE PAPER
FEED (LOWER) ......................................... 7-5
7-3. Connector list .............................................. 7-6
7-3-1. Main CB (UNIT MAIN) .............................. 7-6
7-3-2. High voltage unit (UNIT HV) .................... 7-9
7-3-3. Power supply board (UNIT PSU) .......... 7-12
7-4. IC list .......................................................... 7-13
7-5. Test points and VR list ............................. 7-14
7-6. Electrical parts layout drawing ................ 7-14
7-6-1. PCB, lamp (heater), fuse (rating) .......... 7-14
7-6-2. Clutches (solenoid) and motors ........... 7-15
7-6-3. Sensors and switches ........................... 7-15
Chapter 7 Electricity
7-1. Main control circuits
7-1-1. Toner density control
1. Toner density detection
The TNS signal detected by the toner sensor is relayed by the high voltage unit (UNIT HV) and connected to
CN191-20 on the main CB (UNIT MAIN). After the TNS signal is changed to a partial voltage (TNS! signal) by the
registance in the main CB, it is input into the IC121 (CPU) pin No. 77. The TNS! signal can be measured with the
test point (TP103).
2. Toner motor drive control
1
As the toner is consumed and the toner density becomes lighter than the optimum density, the TSM signal is
output (HIGH -> LOW) from the IC121 No. 23 pin. The drive circuit in the high voltage PCB (UNIT HV) is activated to rotate the toner motor (pulse motor) and supply the toner.
Supply time: 3.5 sec.
1
3. Forced toner supply mode
If the toner sensor detects a light density 1% less than the optimum density three times in succession, this unit
will stop the copy operation, and forcibly supply toner. During this mode’s operation, P25 will display (forcibly
supplying toner).time: Max. 250 sec.
When the toner density is recovered (6.5%), the stopped copy job will automatically resume. However, if the
density is not recovered, P25 will blink (toner empty), and after 30 copies, the copy operation will stop.
4. Initialization of developing unit
When the unit’s power is turned on in the unused state (when installed), P26 will light (developer not initialized),
and the standby state will not be entered. This is so that the compensation voltage TNSC signal (analog voltage)
applied on the toner sensor can be calculated beforehand so that the TNS signal will become the reference
voltage in the new developer (unused) state. When the initialization operation (user mode C-51) is carried out,
the detected compensation data will be saved in the main PCB’s EEPROM (IC123). (Note: The developing unit
must be initialized also when it has been replaced.)
Initialization time: 6 min. (3 min. agitation + 3 min. reading & compensation data registration)
+5V
UNIT HV
+24V
CN1261-5
CN191-18
CN191-17
/TSM
TSMCLK
GND24
TSMCLK
/TSM
UNIT MAIN
CI1251B
CI1251A
TP104
CI1251C
CI1251D
Q1255
Q1256
TP103
TNS!
TNSC!
TSMCLK
TSM
77
45
23
+24V
CN1251
1
Toner supply
motor
2
3
4
5
6
CN1261-4
CN191-19
Toner sensor
Q1251
Q1252
Q1253
Q1254
IC121
5
TNM0
TNM1
TNS
TNSC
MODEL
1312
MANUAL
SERVICE HANDBOOK
REVISED EDITION
7-1
1
DATA
May.1999
PAGE
7-1
METHOD
REPLACEMENT
Chapter 7 Electricity
7-1-2 Fusing temperature control
The surface temperature of the heat roller is detected with a thermistor, and is kept to a constant optimum temperature (188ºC) by turning the fusing heater ON and OFF with the SSR circuit on the power supply PCB (UNIT
PSU).
1. Temperature detection
1
The temperature detection thermistor is contacted against the surface of the heat roller. The resistance value
changes according to the temperature.
Low temperature (20ºC) : 95KΩ~145KΩ
Optimum temperature (188ºC) : 0.9KΩ~1.0KΩ
The FUTHM signal detected by the thermistor is relayed by the power supply PCB (UNIT PSU), and connected to
CN151-B12 in the main PCB (UNIT MAIN). The signal is changed to a partial pressure (TEMP signal) by the
registance in the main PCB. The TEMP signal is changed into a further partial voltage(FU TEMP signal) by the
registance, and input into the IC121 (CPU) pin No. 76. The TEMP signal is approx. 4.14V at the optimum temperature (standard 188ºC), and can be measured with the test point (TP102).
2. Error detection
The TEMP signal is used also to monitor for thermistor errors. If an overheat (FUOVH) or thermistor open
(FUTHOPN) is detected, the heater power is cut off by the safety circuit. If a fault (hardware circuit fault or software hang up) that causes the fusing heater to remain lit occurs, the thermostat connected in series to the fusing
heater operates and cuts off the heater power.
(F34: High temperature error, F35: Low temperature error, F36: Thermistor error -> Must be released with service
mode 25-47)
3. SSR circuit
If the fusing temperature drops below the optimum temperature (188ºC), the SSR signal (LOW-> HIGH) is output
from the IC121 (CPU) pin No. 32, and reversed (HIGH->LOW) by the IC124. Then, the SSR circuit in the power
supply PCB (UNIT PSU) is driven to light the fusing heater.
MODEL
1312
MANUAL
SERVICE HANDBOOK
REVISED EDITION
7-2
1
DATA
May.1999
PAGE
7-2
METHOD
REPLACEMENT
Chapter 7 Electricity
7-1-3. JAM detection
Paper jams are detected with the JAM1 sensor (photo coupler) installed at the paper feed section and the JAM2
sensor (switch) installed at the paper exit section. The JAM1 sensor is set before the slip roller, and also acts as
the manual feed detection sensor.
1. JAM1 sensor
The JAM1 signal (HIGH->LOW when there is paper) output from the JAM1 sensor is relayed by the power supply
PCB (UNIT PSU), and is connected to the main PCB (UNIT MAIN) CN151-B1. It is then input into the IC121
(CPU) pin No. 63.
2. JAM2 sensor
The JAM2 signal (HIGH->LOW when there is paper) output from the JAM2 sensor is relayed by the power supply
PCB (UNIT PSU), and is connected to the main PCB (UNIT MAIN) CN151-B13. It is then input into the IC121
(CPU) pin No. 64.
3. JAM detection conditions
Display code
J11
J12
J16
J31
J32
JAM releasing method: Remove the jammed paper, and then open and close the upper cover.
* After the jam releasing procedure was carried out, J16 may occur again when the paper which was at the paper
feed path was fed. In this case, release the jam again.
* Paper was incorrectly fed from unit standard cassette (upper cassette).
* Paper did not reach the JAM1 sensor within 1.3 sec. after the upper
cassette paper feed solenoid turned ON.
* Paper was incorrectly fed from option cassette feeder (lower cassette).
* Paper did not reach the JAM1 sensor within 3.21 sec. after the lower
cassette paper feed solenoid turned ON.
* There was paper on the JAM1 sensor when the power was turned
ON or the upper cover closed.
* The JAM2 sensor did not turn ON within 2.85 to 3.54 sec. after the
regist clutch turned ON.
* The JAM2 sensor did not turn OFF within 2.85 to 3.54 sec. after the
JAM1 sensor turned OFF.
* There was paper on the JAM2 sensor while waiting.
Detection conditions
Unit operation
* Operation stops after the
previous paper is exited.
* Operation stops after the
previous paper is exited.
* Instantaneous stop
* Fusing heater turns OFF.
* Instantaneous stop
* Fusing heater turns OFF.
* Instantaneous stop
* Fusing heater turns OFF.
7-3
Chapter 7 Electricity
7-1-4. Safety circuit
With this unit, the interlock switch and upper cover open switch are turned OFF when the user opens the upper
cover. The AC power for the fusing lamp and exposure lamp, and the DC power (+24) for the high voltage circuit
shown in the circuit diagram and that for the main motor are cut off. The main relay is cut off in the same manner
when an error signal is detected on the main PCB (UNIT MAIN).
1. Exposure lamp error
The exposure lamp lighting signal (AVRERR: this is not an error signal) is detected and regulated its waveform by
the exposure lamp lighting detection circuit on the power supply PCB. The AVRERR signal is connected to the
main PCB (UNIT MAIN) by the CN1031-B16, and monitors whether the lamp is continuously lit (approx. 15 sec.).
If it is detected that the lamp is continuously lit for 15 sec. or more, the main relay is cut off by the AVRERR signal
(LOW-> HIGH).
2. Fusing heater error
When an error signal (FUTHOPN: thermistor open, FUOVH: fusing overheat) is detected with the fusing temperature control circuit, the AVRERR signal (LOW->HIGH) is generated in the same manner as the exposure lamp
error, and the main relay is cut off.
(F34: High temperature error, F35: Low temperature error, F36: Thermistor error -> Must be released with service
mode 25-47)
7-4
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