Technical Description: Ink System
Issue 2
81
Part No. 306-0430-102
Solenoid Valves
The flow of ink in the ink system is controlled by eight solenoid operated spool valves. Except for valves V11
and V12, the valves (see Figure 33) are all of the same design. The valves are single-acting, operated by an
electrical actuator (solenoid) with spring return. The flow is from the common port (C) (
3
) to the normally open
port (R) (
1
) when the valve is not energised (off). When energised (on) the flow is from the common port to the
normally closed port (P) (
2
). Valves V11 and V12 are miniature shut-off valves and are mounted on the heater
block within the printhead.
V1 Solvent Top-up Valve (located at the solvent top-up reservoir)
When V1 (Figure 32 (
16
)) is energised, solvent top-up is drawn through the valve under vacuum (which is
derived from the suction side of the pump into the ink flow).
V1 is energised for periods of up to 5 seconds when the VMS system detects when the ink viscosity is at least 1
second too thick.
V2 Ink Top-up Valve (located at the ink reservoir)
When V2 (
17
) is energised, replenishment ink is drawn through the valve under vacuum (which is derived from
the suction side of the pump into the ink flow).
V2 is energised when the level of the ink in the FMS mixer tank falls below the ‘Mixer tank OK’ ink level detector.
V3 VMS Diverter Valve (located on the FMS ink system)
The VMS diverter valve (
5
) controls the flow of ink into the VMS chamber via restrictor (R1), which controls the
ink viscosity.
V3 is energised when the VMS system becomes operational under software control or when the ink level falls
below the VMS ‘low level detect’ probe.
V3 is de-energised after a short time delay once ink is detected by the VMS ‘high level’ detect probe.
The time taken for ink to flow out of the VMS chamber through a restrictor orifice between the high and low level
detect probes determines the ink viscosity.
When V3 is de-energised, the flow of ink is directed into FMS mixer tank.
V6 Feed Valve (located on the FMS ink system)
The feed valve (
3
) is used to control the flow of ink to the printhead.
When V6 is energised, ink is allowed to flow to V11 in the printhead and out through the nozzle.
V7 Flush Valve (located on the FMS ink system)
The flush valve (
6
) provides either vacuum (which is derived from the suction side of the main system pump) or
pressure to the flush solvent which controls the flush pump to direct flushing solvent to the nozzle during ‘clean
jet start’ and ‘shutdown’.
The flush pump is primed by vacuum being applied to the flush pump diaphragm when V7 is de-energised.
System ink pressure is applied to the flush pump diaphragm to direct pressurised solvent to the nozzle when V7
is energised
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