Xerox WorkCentre XK50cx, Service Manual

Page: 56 / 109

4-29
Circuit
+5V OUTPUT TERMINAL
Square wave voltage generated by Ns1 produces
DC voltage rectified and smoothed by half-wave
rectifier. This voltage put in to a three-wire regulator
generates stable DC power of +5V.
+30V OUTPUT TERMINAL
Square wave voltage generated by Ns2 is rectified
and smoothed by half-wave rectifier and supplies
load with output voltage without separate
regulation.
+12V OUTPUT TERMINAL
Square wave voltage generated by Ns3 is rectified
and smoothed by half-wave rectifier, and then
detected by voltage detector. Signals compared by
error amplifier are fed back to primary PWM
control circuit through photo coupler.
PWM control circuit controls the voltage of power
transistor gate driver according to the voltage to
supply load with stable output voltage.
4-6 Others
4-6-1. Paper Sensing Circuit
This circuit senses whether there is paper or not, and
whether the paper is fed or not.
If LF motor picks up a paper, the lever will be lifted
and output “/P_Check” will become “Low”.
If the “/P_Check” is not low after picking up, the
“Paper Check” LED will be turned on.
4-6-2. Document Sensing Circuits
(Document Detecting Sensor/Scan
Position Sensor)
This circuit senses whether document is detected or
not. If a document is detected by ADF_P_DET
sensor, copy operation is ready. If the document is
detected by ADF_P_DET sensor, copy operating is
ready. If the document is detected by ADF_P_POS
sensor, scanning is performed.
Document sensing operation is similar to paper
sensing circuit’s operation.
4-6-3 Home Sensing Circuit
This circuit checks whether carriage is at home or not.
A encoder sensor is used as a home sensor to detect
home position. This encorder sensor uses a encoder
strip, attached to a main frame, to detect current
position and moving direction. A encoder sensor
outputs CHY and CHX signal to main controller (Main
PBA: U15 - 33 & 36). U15 uses these two signals to
sense the carriage’s position.
4-6-4 Temp IC Driving Circuit
TEMP IC(DC1821 Digital, Thermometer) mounted on
the sensor card on the back of the carriage is used to
read the temperature around ink cartridge.
This IC converts the temperature around IC package
into digital value and sends the temperature data
serially to a main controller (Main PBA: U15) to
calculate the temperature around the head.
It senses temperature so that the temperature of the
head can be the optimum when the machine prints
something.
The above IC sends data serially into DUOIP2 (Main
PBA: U16).