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Samsung Electronics
SUMMARY OF PRODUCT
Service Manual
3) Paper Feeding, Toner Cartridge Sensing
When paper passes the actuator (feed sensor part), it detects the signal of Photo interrupter, informs the
paper feeding state to CPU, and then sprays the image data after certain time.
If it doesn't detect the feed sensor within 1 sec. after paper is fed, paper Jam0 is occurred (Red and Yellow
will be turned on among the OP panel LEDs), and the fact whether the developer is inserted or not is detect-
ed with the same principle. After the developer is mounted, the actuator is operated. The signal from the photo
interrupter is detected when it is passing the actuator of the sensor part. That is the developer ID sensing.
4) Paper Exit Sensing
It detects paper state whether paper gets out from the set with operation of exit sensor on the engine board
and actuator on the frame. Paper detects the on/off time of exit sensor, and the normal operation or jam infor-
mation is informed to the CPU.
The paper JAM2 is informed. (Red, Yellow LED will be turned on among the OP panel LEDs)
5) Cover Open Sensing
The Cover open sensor is located on the front cover. After the front cover is opened, +24V (DC fan, solenoid,
main motor, polygon motor part of LSU, HVPS), which is supplied to the each unit, is cut off.
The cover-open sensing is operated by the D0 bit of CPU, and the developer ID sensing is operated.
In this case, the red LED among OP panel LEDs will be ON for informing the facts to user.
6) DC FAN / SOLENOID Driving
It is driven by transistor and controlled by D6 bit of CPU.
When it is high, the fan is driving by turning on the TR, and it is off when the sleep mode is selected.
There are two solenoids, and they are driven by paper pick-up and MP signal. Its driving time is 300ms. The
diode protects the driving TR from the noise pulse, which is flown when the solenoid is de-energizing.
7) Motor Driving
The motor driving circuit is formed when the Driver IC is selected in the first place. The A3977 (Motor driver
IC) is used in this case. But, the resistance Rs value of sensing and the voltage value of the V reference can
be changed by motor driving voltage value.