[jws]

This only applies to color laser printers and color copiers. Your inkjet printer is just fine.

The wikipedia article on laser printers links to a nice sample on a 1cm ruler... http://en.wikipedia.org/wiki/File:Printer_Stenography_Illust...

The part of this that I find most interesting is that these have been known since the 90s and in 2005 there was a flurry of interest as some of the schemes were decoded, but I have never seen an authoritative reason why they are there. Does some entity in the US government require them? By what legal mechanism? Are the printer manufacturers trying to avoid liability for manufacturing counterfeiting equipment?