Ken said:
Base for cost comparisosn
It was a Konica Minolta 2400 for which I always thought the cost per page
figures quoted were for 5% coverage - a quarter of the Staples statement.
Ken
Staples gave you the 5% coverage figure at 5% for each colour, and since
there are four colours, quoted 20% coverage. This is nonsense IMO, but
common. The correct quote IMO should be "at 5% coverage, using all four
colours." But what that means in terms of coverage for each colour is
another question. 5% coverage is 12 pt text double spaced with approx.
2cm margin on an A4 or 8-1/2x11 page -- or so it was described to me
once, when I asked. If you use coloured text, obviously you still have
5% coverage, just a different combination of inks.
For black (single colour) printing the 5% coverage standard is well
established, and works if accompanied by qualifiers such as "at letter
quality printing." It's also related to the real world, since a typical
business letter with letterhead amounts to about 5% coverage. (Note that
this standard refers to the amount of space taken up by each character,
_not_ to the amount of space taken by the ink dots, which is another
issue, see below.)
20% coverage would be a strip about 12cm wide from one edge of the page
to the other. What this means in terms of % coverage in terms of ink is
something else again. It depends on whether the inks are layered, or
printed next to each other (like the pixels on a screen), or partly
overlapping, or spaced apart. That's a matter of printer technology and
printing quality. I've been told that different printers lay down the
ink or toner differently.
Then there is the issue of draft vs high-quality printing. Draft
printing will use as little as one quarter of the ink used by HQ
printing - which means than "coverage" is less for the same size image
or typeface. These considerations make "x% coverage" a term with little
relation to the real world use when it comes to colour printing.
IMO, colour printing costs should be based on full colour, HQ 4" x 6"
(10cm x 15cm) prints. Not that I insist on this size - I just want a
common base of comparison. "x% coverage" is not good enough for colour
printing.
HTH