A court action has forced Hewlett-Packard Co to change the illustration on packages of two of its black inkjet printer cartridges when a judge in a US district court ruled that it suggested that rival refill kits from Dallas-based Nu-Kote International Inc – sold at half the price – are incompatible with HP printers. HP claims success because the judge turned down a Nu-Kote demand that it stops making new cartridges with the ink hole at the bottom rather than the top. But whichever way the orifice points, this is serious business as Business Week has estimated that inkjet supplies accounts for a stunning 25% of HP’s profit.