HP Deskjet 1220C - Strange character on page when printing

My boss has a Deskjet 1220C set up on her computer locally through a
USB port. What is happening is whenever something is printed on this
printer, no matter what is it, word doc, excel, picture file, etc, it
always adds 1 strange character at the bottom of every page. The
problem is sometimes resolved when the printer is turned off and then
turned on again but then after a while, the problem returns again. I
tried downloading the latest drivers from HP's web site and
reinstalling teh printer and the problem continues. She is running
Windows 2000 and is connected to a domain. Any ideas what could be
causing this?

Thanks in advance.