It appears to come directly from the pages of a James Bond novel.  A very unique ink-jet printer cartridge, containing explosive ink, has been patented by the British Ministry of Defence.

The ink is a mixture of very fine aluminum particles, each 1 micrometer in diameter, particles of copper oxide 5 micrometers wide, epoxy varnish and alcohol.   The ink is stable in liquid form, making it safe to print onto conventional paper, but forms an explosive fuse once dry.

An engineer can easily sketch out a printable fuse using computer imaging software, changing the delay in milliseconds by altering the length, thickness and pattern of the line on the paper.

The ink can then be printed between a small strip of metal and a larger patch of explosive ink.  Feeding a current through the metal strip makes it hot enough to ignite the fuse, which burns until it reaches the explosive patch.  This explosion can then trigger the detonation of a much larger amount of explosives.

You will probably see some shady manufacturer doing label printing with one of those secret inkjet coders.  Watch out!  Letter bombs might be coming back into popularity with this new invention.