Samsung SF-530 Series, Руководство по обслуживанию

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CIRCUIT DESCRIPTION
Samsung Electronics
Repair Manual
3-4-2-11. Environment Recognition
THV voltage recognizes changes in transfer roller environment and allows the voltage suitable for the environment in order
to realize optimum image output. The analog input is converted to digital output by the comparator that recognizes the envi-
ronmental changes of the transfer roller. It is to allow the right transfer voltage to perform appropriate environmental
response considering the environment and the type of paper depending on this digital output by the programs that can be
input to the engine controller ROM.
For ML-5000 or ML-5200 series, this environment recognition setting is organized as follows: First, set the THV(+) stan-
dard voltage. Allow 200M
Ω
load to transfer output, enable output and set the standard voltage 800V using VR201. Then
set 78 (CPU's recognition index value) as the standard using VR302. This standard value with CPU makes sure that the
current feedback is 4µA when output voltage is 800V and load is
200M
Ω
.If the load shows different resistance value when 800V is output, the current feedback will also be different and
thus the index value will also be different. according to the index value read by CPU, the transfer voltage output will differ
according to the preset transfer table.
The changes in transfer output required by each load is controlled by PWM-DUTY.