Brother MFC5100C Service Manual page 29

If the controller issues a print command, a biased voltage will be applied to all electrodes formed
on the surface of the piezoelectric ceramic so that each actuator will be distorted as shown with
broken lines.
If the electrodes on a target channel are deenergized according to drive signals, then the associated
piezoelectric ceramic actuator returns to the previous form so that the ink in the manifold will be
vacuumed out to the channel.
If the voltage is applied again, the piezoelectric ceramic actuator will be distorted again to apply
pressure to the ink in the channel, causing the ink to jet out through the nozzle. The jetted-out ink
drop will be splashed and produce a dot on paper held by the platen.
As the carriage holding the print head unit travels at the printing speed, the controller sends print
command pulses to the piezoelectric actuator driver circuit embedded in the print head unit.
(2) Ink cartridges
The machine uses four ink cartridges (black, cyan, yellow, and magenta) of disposable type to
supply ink to the print head unit. As shown below, an ink cartridge contains an ink-impregnated
urethane foam. If ink-jet print operation or purging operation takes place, ink comes out of the
urethane foam and is supplied to the print head unit through the ink room, filters, and manifold.
For the ink cartridge sensors on the carriage PCB, refer to Subsection 3.2.3.
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