System Card Assembly - Lexmark MB790MFP Service Manual

System card assembly

The system card assembly controls printing operation based on the communication with the RIP controller and
optional peripherals. It also controls toner dispense, fuser control, sensor switch feedback, drive motors,
clutches and solenoids
Control
Printhead control
Rotation of printhead motor
The on/off control of the printhead motor is performed according to the mode of operation as shown below.
Operation mode
Standby mode
Print mode
Sleep mode
Determination of printhead ready
The printhead goes into ready state after the specified period passes since the reception of the printhead MPA
start signal and the SOS cycle exceeds the reference value.
Printhead reference value
Printhead reference value
Ready reference value
Fail reference value
Fuser control
Fuser control method
The on/off control of the main/sub heater lamps is performed based on the fuser control temperature. The fuser
transmits between the five states (warm up, ready, standby, print, and low power) depending on the heat roll
surface temperature or printer conditions.
The fuser temperature control starts when the fuser ready in the system card assembly is turned on after a
preset time period has passed from power on. If a failure occurs, the heater lamps are turned off, the fuser
ready is turned off, and then the fuser temperature control is stopped.
Fuser lamp on/off control
The thermistor detects the heat roll surface temperature (fuser temperature) to regulate the temperature at the
target control temperature by turning on or off the heater lamp.
PRINTHEAD motor on/off
Always off
Turns on upon receiving the signal from the controller,
and turns off after a preset time has passed from the
end of printing. Also turns off if a print command is not
received within 30 seconds from the reception of the
signal.
Always off
SOS signal interval (equivalent to 98% or more of the rated RPM of the
printhead motor)
SOS signal interval (less than 98% of the rated rpm of the printhead
motor)
Description
Diagnostic aids
7462
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