Inkjet Printer Operation
(From: Tony Hardman (AHED_CIJ@f54x19.demon.co.uk).)
There is a US publication called 'The Hard Copy
OBSERVER' from Lyra Research Inc. Tel: (617)
322-0708.
This discusses the latest technologies and who does
what. It may not cover the print head technology
very much but is a good read if you are into print
technology in general.
There are many companies that sell variable print
processes. One I have heard of is RALFLATAC. They do
a brochure that does an excellent brief of most
technologies available for printing. They have UK
(and many other sites in europe) and US sites. UK
Tel 01732-583661, US Tel (704) 684-3931.
I have no idea if you can easily get copies of
either publication from them so here goes a very
very brief description.
Ink jet printing has two main types, continuous ink
jet (CIJ) and impulse printing (DOD) (drop on
demand). Each of these can be a single jet, or an
array of jets.
-
CIJ as a single jet is used on product
identification (sell by dates, serial numbers)
on high speed industrial applications.
CIJ is a continuous jet of ink cycling round a
system and occasionally (when required) a drop
is deflected out of the stream onto the paper.
The stream is modulated to break it into a
consistent drop size. The deflection works like
the beam on an oscilloscope. If you charge 1
drop and pass it between two high voltage plates
it is deflected. This system also requires
cunning mechanics, but the support electronics
is much more complex, and probably one of the
reasons for its performance limitations being
not up to what you might expect. The
calculations of the aerodynamics of drops being
deflected is no small task, even if look up
tables are used.
-
DOD is often an array of small jets used on desk
top printers.
DOD works in principal like an old Dot Matrix
pin printer. Instead of firing a pin at a
ribbon, a drop of ink is fired at the paper. The
drop is fired by either a piezo crystal
squeezing the ink out of a small tube, or by
boiling the ink and the vapor forces the ink out
of the chamber. The key to both of these
processes is in the mechanical design of very
small components if 300 dpi is required. The
control electronics is a bit cunning, but I
figure it is the easy bit.
Printer and Photocopier Troubleshooting and Repair
Collection
Version 2.48
Copyright © 1996-2001
Samuel M. Goldwasser
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