[LINK] Green ICT ideas and ink costs (Link Vol 208 #42)

[Phillip Musumeci]

At 09:57 PM 27/03/2010, stephen at melbpc.org.au you wrote:

>
> >The move is part of the school's five-year plan to go green -- and save
> >money. Printer ink costs about $10,000 per gallon.
>
> That figure cannot be right. Does it have gold in it?

~~~text cut~~~

> That's. $27.50/ounce times 128 = $4800/gallon.
> Even the manufacturers price is only $71 for each individual
> cartridge in total. $44.37/ounce times 128 = $5680/gallon


Ink for inkjets can be extremely expensive because of the high material
demands.

Example: very high speed industrial inkjets are shooting ink at paper moving
>1m/s (3.6km/hr) and the ink droplets can easily bounce off the paper
surface.  The adhesive force characteristics of the ink have to be strong
enough with the paper fibre to have the droplet be "sucked into" the paper
on contact or for surface printing there must be rapid drying, preferably
without a smudge effect as the paper moves.   Ideally, the payload of the
ink (some particles with a desired colour or some such optical property)
must be reliably lodged inside or onto the paper surface.

At the same time, the ink must not adhere so strongly to the print head
chamber (often a piezo crystal) that it is too hard to shoot out by heating
or squeezing, but it must adhere strongly enough that it won't evaporate and
cause print heads to need priming and break print on demand.

In around 2000, black inks satisfying these sorts of requirements cost
approx. $1500 or more per litre and I guess the price has since increased.
 By the way, the disclosed contents of some inks did not seem particularly
safe to me and yet they were "standard industry practice" - maybe it is a
good thing that ink is expensive and droplets are small.

Phillip Musumeci