HP 1055CMHP - Manual (Page 295)

Functional Overview
10-9 HP DesignJets 1050C and 1055CM Printers Service Manual
At the ink collector there are two metallic pins between which the
resistance is checked. When there is no leakage, there will be air
present and the resistance measured will be high. In case of leakage,
the collector will contain ink and there will be a potential short circuit
between both electrodes through the ink, and the ink leak will detected.
The LDS measures the resistance in the collector: if this resistance
is below the threshold value, then the system will assume there is
ink in the collector and the Printer will be stopped.
Service Station
The Service Station consists of a linear motion mechanism with a
chassis containing one PrintHead Cleaner (PHC) for each printhead.
Each PHC consists of one spittoon and reservoir, sled-type cap
nozzle wiper and pen snout wiper. Attached to the Service Station
chassis, one optical drop detector provides nozzle check
functionality.
Wipers are located symmetrically on the PHC. This, together with
the Scan-axis Printhead to Printhead distance (32 mm) enables
separate color / black wipe.
A positive pressure priming system is implemented that injects air
into the printhead regulator bagafram to induce a controlled
drooling. Airflow channels are integrated into the latching system
springbeam, which deliver air to the bagafram ports. The priming
pump is integrated into an articulating lever mounted on the right
side of the service station. The priming process occurs with each
printhead over its respective spittoon to handle waste ink and
facilitate post-priming servicing routines
.
Print Head Cleaner (PHC)
The PHC case is the main structural part of the replacement module.
It is the part that the customer handles and contains the other sub-
components:
n Wiper.
n Spittoon.
n Cleaning fluid.
n Cap sled assembly.