Ricoh has filed lawsuits against Taiwan's two major compact disc manufacturers and six of their affiliates in U.S. federal district courts, claiming they infringed its patents on optical discs. On Monday, the office equipment maker filed separate suits against LITE-ON IT Corp and its four affiliates as well as CMC Magnetics Corp, an affiliate and sales agency, with the courts in Texas and California. Ricoh is also seeking compensation from them.