[Printers] HP Color Laserjet 2500 Results

[Seth David Schoen]

Patrick Burns writes:

> Good to hear there will be more scans coming soon.
> 
> Is it just me, or do the Toshiba and Kyocera dot patterns sound a lot
> like the HP patterns? I.e. 23x18 grid of dots (including blank
> columns/rows).

I think I'm going to try to start classifying printer models by the size
of the grid they produce, if any, in the hope that the printers will
then divide into "bins".

I'm very curious about printers with subtle differences.  For example,
as I believe someone has already mentioned here, some of the Epson
Aculasers use the same 15x8 grid as the Xerox DocuColor, except that
it's rotated to make it 8x15.  The Aculasers do encode serial number
using the same scheme as the DocuColors, but they don't seem to encode
date and time, and they use columns 2 and 3, which are unused on the
DocuColor.  I don't know how we get a manufacturer code out of this; I
doubt that it's represented in column 15 (as some people have suggested)
because some DocuColors print a completely blank column 15.  It is
possible that the orientation of the grid identifies a manufacturer, but
this feels unlikely (because you could just print in landscape mode to
alter the orientation, and in any case because it also looks like the
Dell printers may be printing the same 8x15 grid).

-- 
Seth Schoen
Staff Technologist                                schoen at eff.org
Electronic Frontier Foundation                    http://www.eff.org/
454 Shotwell Street, San Francisco, CA  94110     1 415 436 9333 x107