Xerox ColorQube 9303 Series Service Manual page 1764

Ink Melt Heaters
Ink sticks are delivered by the ink loader and held against the ink melt plates by gravity only.
The system contains four melt heater / plate assemblies, one for each ink stick colour (cyan,
magenta, yellow and black), Figure 15. The ink melt plate is heated using a ceramic Positive
Thermal Coefficient (PTC) disk to emphasis safety in the ink melt system; as the temperature
of the melt plate rises, the electrical resistance increases reducing the electrical current drawn
by the heater. When the melt heater reaches the correct temperature the part of the ink stick
that contacts the plate melts and the liquid ink runs into the low pressure ink reservoir below.
Figure 15 Ink melt heaters
Ink Reservoir
The ink reservoir consists of a low pressure ink reservoir, a high pressure ink reservoir, 16 disk
valves, a reservoir heater and manifold plates. Refer to
Principles of Operation
Figure 16.
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Figure 16 Ink reservoir detail
Melted ink is received on the low pressure side from the ink loader melt plates through holes at
the top of each color reservoir. Each color reservoir is divided into four areas (one for each
printhead). If the air solenoid for a particular area is not energized, then a mechanical flapper
valve between the low and high pressure side opens to allow the ink level in the low and high
pressure side to equalize up to the fill limit determined by the ink level sensor. If the air solenoid
for the a particular storage area is enabled then the high pressure side will go to ~ 4 lbs. of
pressure and this pressure will close the mechanical 'flapper' valve between the high and low
pressure sides of the reservoir. The low pressure side may continue to fill but the high pressure
side cannot fill until the air solenoid for that storage area is de-energized.
Varying air pressure (purge, fill or low pressure assist) is accomplished by an electrically oper-
ated valve on the air pump motor assembly. When energized (open) the pressure drops for low
pressure assist which places enough pressure on the jets so that the ink will stick out of the jet
and provide lubrication for the cleaning blade but will not run, resulting in increased wastage.
When the solenoid is energized, ink flows from the high pressure side to the ink router plates
which comprise the lower portion of the ink reservoir, then to the appropriate umbilical connec-
tion and on to the appropriate printhead.
CVU (Check valve unit)
ColorQube® 9303 Family