Microsoft late Tuesday filed its formal appeal of a patent infringement ruling that threatens to halt sales of Word in its current form.

In May, a jury ordered Microsoft to pay $200 million for infringing on a patent held by Canada's I4i. Earlier this month, a federal judge increased that monetary award and also issued an injunction barring sales of Word that include the custom XML code found to infringe on I4i's patents.

"We believe the court erred in its interpretation and application of the law in this case and look forward to the September 23 hearing before the U.S. Court of Appeals," Microsoft spokesman Kevin Kutz said in a statement.

In its papers, Microsoft makes a number of arguments for overturning the infringement finding, saying that the judge made several procedural errors and failed to live up to his role as "gatekeeper."

More: http://news.cnet.com/8301-13860_3-10318263-56.html