I just read a news article on Techworld telling me that an Australian researcher has discovered that laser printers give off significant levels of particulates.
I can't say I was surprised. In fact, my reaction was more along the lines of: "No shit, Sherlock".
I remember early laser printers - things like the first Apple LaserWriter, and early HP LaserJets and Canon lasers. You'd put them in a room that wasn't normally occupied by people because of the fog you'd have to fight through in order to pick up your printout. This was particularly true if the printers were getting a bit long-in-the-tooth, which was often the case as those early models were very well made - almost bulletproof - and lasted for years.
Modern laser printers are, of course, far better on the lungs than their ancient predecessors, both in terms of particulate emission and things like going into auto-standby mode during inactive periods. But given that the way they work is to drop powder onto a sheet of paper and then fuse it in, it should be no surprise that some tiny fraction of this fine powder escapes into the air.