During the operation of phase-change ink-jet printers a bubble formation
phenomenon often occurs. These bubbles are detrimental to the operation of
the printer and substantial efforts are made to remove them. The objective of
this research was 1: to develop a fundamental understanding of how bubble or
void formation occurs during the phase-change process, and, 2: to develop a
simple computer model to simulate this behavior which can then be used as a
tool for better design of print-head geometries.
Preliminary experimental work indicated the void formation to be a result
of the density change accompanying the phase-change process.
The commercial numerical code, Flow 3-D, was used to model the
phase-change process in print-head geometries and substantiate certain
simplifying assumptions. These assumptions included the effect of convection
on the process and the effect of the varying material properties.
For channel sizes less than 0.5 cm the phase-change process was found
to be a pure conduction process. Convection effects are thus negligible and
can be eliminated from the model. The variability of density, specific heat and
thermal conductivity must be included in the model, as they affect the phase-change
process dramatically. Specific heat is the most influential of the
properties and determines, along with the conductivity, the rate at which the
phase change takes place. The density must be included since it is directly
linked to the void formation. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35652 |
| Date | 05 May 1994 |
| Creators | Coven, Patrick J. |
| Contributors | Welty, James R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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