Help! My printer, a Xerox Docuprint M750 (parallel port), has begun spewing out different primary-colored meaningless characters while printing documents. I build systems regularly, but I'm a complete novice when it comes to printers. I haven't done a lot of maintenence with it, yet it gets fairly rare use. I've checked all the levels of the different cartriges as well as ensured that it has a good clean connection to the back of my case. Any help would be great. Thanks!

1Ghz Athlon T-Bird
Asus A7V
768MB PC-133 SDRAM
2x40G West. Digital ATA/100
Nvidia GeForce2 MX
Soundblaster Live! Platinum 5.1
Intel Pro NIC 10/100
HP 9100 CDR/RW
Pioneer DVD-ROM
MS Intellipoint Optical USB