Samsung ML-3471ND/XAX Service Manual page 35

Product specification and feature
2.2.3.3 Engine F/W
2.2.3.3(a) Control Algorithm
Feeding
If feeding from a cassette, the drive of the pickup roller is controlled by controlling the solenoid. The on/off of the solenoid
is controlled by controlling the general output port or the external output port. While paper moves, occurrence of Jam is
judged as below.
ITEM Description
JAM 0 - After picking up, paper cannot be entered due to paper is not fed.
- After picking up, paper entered but it cannot reach to the feed sensor in certain time due to slip, etc.
- After picking up, if the feed sensor is not on, re-pick up. After re-picking up, if the feed sensor is not on
after certain time, it is JAM 0.
*It is a status that the leading edge of the paper doesn t pass the feed sensor.
-Even though the paper reaches to the feed sensor, the feed sensor doesn t be ON.
*It is a status that the leading edge of the paper already passes the feed sensor.
JAM 1 - After the leading edge of the paper passes the feed sensor, the trailing edge of the paper cannot pass
the feed sensor after a certain time. (The feed sensor cannot be OFF)
- After the leading edge of the paper passes the feed sensor, the paper cannot reach the exit sensor after
certain time. (The exit sensor cannot be ON)
*The paper exists between the feed sensor and the exit sensor.
JAM 2 - After the trailing edge of the paper passes the feed sensor, the paper cannot pass the exit sensor after
certain time.
Transfer
The charging voltage, developing voltage and the transfer voltage are controlled by PWM (Pulse Width Modulation). The
each output voltage is changeable due to the PWM duty. The transfer voltage admitted when the paper passes the
transfer roller is decided by environment recognition. The resistance value of the transfer roller is changed due to the
surrounding environment or the environment of the set, and the voltage value, which changes due to the environments, is
changed through AD converter. The voltage value for impressing to the transfer roller is decided by the changed value.
Each voltage value is controlled according to 3.3.3.2 Timing Chart.
Fusing
The temperature change of the heat roller s surface is changed to the resistance value through the thermistor. By
converting the voltage value, which impressed to the resistance, to the digital value through the AD converter, the
temperature is decided. The AC power is controller by comparing the target temperature to the value from the thermistor.
If the value from the thermistor is out of controlling range while controlling the fusing, the error stated in the below table
occurs.
Service Manual
2-26
Samsung Electronics