Yesterday, a judge issued an injunction that, if it remains in force, would compel Microsoft to stop selling recent versions of its phenomenally popular program, Word.

The injunction is the latest round in an intellectual property battle that's been brewing since May, when a jury found Microsoft guilty of infringing a patent held by a Canadian company called i4i. Ironically, the patent in question covers a method of separating formatting information from runs of text when documents are written to files—something Microsoft itself received a patent for just this week. Unfortunately, the folks in Redmond filed theirs six months behind the competition.

The i4i patent in question was filed in June of 1994 (and granted in 1998), whereas Microsoft's dates from December of that year. It describes a general method of handling the formatting information in documents by separating it out from the text that's being formatted. In this sense, it's a superset of Microsoft's new patent, which claims similar capabilities but is exclusively targeted to XML file formats.

The company that owns the patent, i4i, sells document management and publishing solutions, so (as noted in the initial ruling), it has actually been using the technology in question. That ruling, which came in the wake of a jury trial, set damages at $240 million and tacked on another $37 million of interest, and it noted that a separate injunction would eventually be issued. That injunction was handed down yesterday, and it bars Microsoft from selling any form of Word that reads the formatting information out of a .DOCX or .DOCM file.

It could have been worse; the original suit also claimed that .NET and Vista infringed the patent. The injunction does allow Microsoft to sell a version of Word that strips out all the XML elements, or one that loads the XML as plain text.

At the time it was issued, Microsoft indicated it would fight the ruling that granted i4i damages. The current injunction also gives the company 60 days to comply, which would be plenty of time to seek a stay of this ruling, pending its appeals. It's not clear whether the fact that Microsoft has since been granted a patent for the specific technology at issue here might influence further legal proceedings.

In any case, despite the fact that this case pitted a Canadian company against one based in Washington state, the legal action took place in the patent-friendly East Texas District Court (though we hear that, thanks to the huge influx of patent cases over the last few years, East Texas isn't quite so "friendly" these days, nor is it the "rocket docket" of old).

At the time Microsoft's XML patent was issued, we speculated that the company might have pursued it for purely defensive purposes. It seems that the patent's ability to shield Redmond will be put to the test very quickly.