You can try to see if there is an updated version of the Lexmark printer driver available.

Thanks co-rel, but I'm running the latest lexmark drivers. It's not the problem. This first happened a few months ago and i didn't relate it to a firefox update - not sure which one it was now. I spent ages following techy forum suggestions and eventually made one too many registry changes and screwed up printing entirely. It's only now after a recent reinstallation of windows that the problem came back and i realised it's a firefox bug and not the fault of lexmark. As i say, it works fine in IE.