HP 2500C Series - Manual (Page 125)

Functional Overview 6-5
Writing System
Bubble collapse begins refill.
As the bubble collapses, the ink in the orifices retracts, breaking off the ejected drop of
ink and drawing the meniscus into the orifice. The surface tension in the deformation of
the meniscus produces the suction to draw in fresh ink to refill the chamber.
Meniscus settles to complete refill.
This process repeats up to 12,000 times a second and creates residual heat in the resistor.
A layer of silicon is placed above the resistor to cool it by conducting away the residual
heat.