Transfer Roller - Samsung SCX-4200 Series Service Manual

3.3.5 Functional Requirements of Environment Recognition
It is intended to gain the index to indicate the inner environment in a present machine. The engine is divided into
several levels with the index.
It is used to control high-voltage values deciding the warm-up time, the fixing temperature and high voltage value to
supply to the developer unit.

3.3.5.1 Transfer Roller

There are two cases to recognize the environment for taking the environmental index.
Recognizing Environment without paper: It is operated when OPC is revolved without the paper.
Recognizing Environment with paper: It is operated when the front edge of the paper is between the transfer roller
and OPC
3.3.5.2 Air Temperature Sensor
N/A
3.3.5.3 Environment Recognition
There are several reference voltages to supply to the transfer roller in order to recognize the environment. At first, it
supplies the lowest voltage to the transfer roller and then when a fixed time is elapsed, it reads the resistance value
of the transfer roller by means of the ADC unit. It operates until the value is lower than a specified value. If the value
is lower than a specified value, it decides an array index for the voltage and then searches an appropriate index in
the table presented by the developer team
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