Microsoft and IBM have been accused of patent violation in a lawsuit filed in Texas last week by the Massachusetts Institute of Technology and a California software firm.

Electronics For Imaging, which holds an exclusive license for image editing software developed by MIT, is demanding licensing fees backdated for six years from 94 firms, Associated Press reports.

EFI, which gained control of the patent in 1990, has licensed it to 16 firms (including Apple and Xerox), for use in devices such as photo scanners and digital cameras. MIT gets a share in revenue from the patent, which expires later this year. ®