I won't argue that the current piezo head designs, especially with the
now popular faster drying pigment inks don't clog, because that would be
an unfair comment. The can and do. In general, if one considers most
cases of clogging as repairable conditions with a bit of home
maintenance, I would say that piezo technology can provide a longer
total life of the head than thermal. Clogging of piezo heads when used
with reasonable quality dye inks is usually a relatively simple matter
to resolve, although it may cause wasted ink and other bothers, but the
head itself can usually be restored to as new output.
Do HP, Canon or Lexmark, as the main producers of thermal heads, provide
a mean estimated lifespan in terms of number of droplets of ink per
nozzle before failure for their heads? Epson, as a piezo device
manufacturer used to provide numbers for each nozzle, although I note
they have gone away from publicizing that information in recent years.
For instance, they used to regularly spec their heads with reliability
of "2,000 million dots per nozzle", so I was wondering if the thermal
companies do or have done something similar for their "permanent" head
designs (of course, this assumes "quality" inks are used, if that is an
issue in head life for these types of heads).
I have certainly seen some catastrophic failures of Epson heads, so I am
not suggesting they are without defects or lifespans, but they are
designed differently, and I would therefore be quite interested if there
are any numbers around to suggest that some thermal heads outlast piezo
heads, and if so, whose and under which conditions.
Art