Printer Control - Lexmark W820 Service Manual

4025-XXX

Printer Control

Printer control is a broad term that is used to describe the printer resources that monitor
and control the actions and operations of the print engine - from warm-up, through the
print cycle, to machine error detection. The center of printer control for the base engine is
the Machine Control Unit PWB, or MCU PWB. The MCU PWB provides the logic and
information processing that is necessary for the printer to function. Almost every electrical
component within the printer is connected either directly or indirectly to the MCU PWB or
to the I/O PWB. The MCU polls the status of sensors in the printer and compares that
information to timing tables that are stored in onboard memory. Acting on the results of
the comparison, the MCU sends commands to various printer components or to the I/O
PWB; switching on motors, switching off voltages, signaling statuses. Non-Volatile RAM
on the MCU PWB stores adjustable operation parameters, such as fuser temperature and
laser intensity, that are used as reference values during printer operation.
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