If you are speaking of the Tektronix/Xerox models using wax based inks,
the answer is yes, it is recommend to keep the printer "on" all the
time. However, these printers have a number of different levels of
sleep cycles, and the lowest one, which is what it drops to when not in
use for a few hours, is not very demanding in terms of electrical use.
The main thing is to keep the wax inks within the heads in liquid form.
If the printer is shut down for a length of time either intentionally
or due to a loss of power, it usually requires a purge of the solid ink,
and that wastes a fair amount of ink.
These printers are fast and pretty conservative with ink usage, and
relatively inexpensive to run, but they tend to be costly initial
investments. They work well with text and spot color. The photographic
output tends to be somewhat contrasty and color accuracy is so-so. They
are improving all the time, and are pretty fast printers. The output
has a waxy feel to it, which sometimes can crack if the paper is
creased. Not good for lamination. The wax inks can scratch off the
paper as well, and transfer with heat.
The dyes used in the ink are not permanent, and will fade relatively
quickly, although again, improvement with each generation.
Environmentally, the printer has little waste, as the main consumables
are the wax inks and paper. No major parts to replace or containers to
toss out. However, I am not use how recyclable the prints are due to
the waxy inks.
Art
