Microsoft has asked the US appeal court to reconsider ruling that will see the software giant fork out $290 million in damages.

Microsoft was charged with using a patent owned by i4i in a feature in Word 2007 that lets people create custom XML documents.

In December, the Court of Appeals for the Federal Circuit upheld an earlier judgment that left Microsoft with the damages and the injunction requiring it to stop selling copies of Word that include the feature by January 11, 2010.

Now Microsoft is asking the panel of judges primarily to reconsider the way that the damages figure was determined.

"The petition details significant conflicts we believe the December 22 decision creates with established precedents governing trial procedure and the determination of damages, and we are concerned that the decision weakens judges' authority to apply appropriate safeguards in future patent trials," said Kevin Kutz, director of public affairs for Microsoft.

i4i said it expected Microsoft to file such a petition and that it looks forward to building its business now that Microsoft is required to stop selling the offending products.

Microsoft has said it has hit today's deadline and will only sell copies Word 2007 with the feature in question removed.

A response to Microsoft's rehearing request may not come for a while. Three judges will review it first, and they'll have seven days to either comply with or ignore it, signaling that they deny the request.

If they deny it, the rest of the panel of judges will then have time to review the request.

A rehearing could result in reduced damages and changes to the injunction.

Small business IT advice

See also: Microsoft makes Office 2007 patch available