Samsung SCX-4216F Service Manual page 128

SUMMARY OF PRODUCT
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 detected 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 nor-
mal operation or jam information 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 operat-
ed.
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 select-
ed.
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.
Service Manual
4-12
Samsung Electronics