My printer is about 4years old now, hp1220c A3 beasty, but latley its been doing funny things. the printer head thing judders for a few seconds, then flies over to the other side then judders there for a bit..this only seems to happen when i try to print onto glossy paper (which isn't hp brand by the way) and its ok with normal paper etc. Thing is, i've printed onto this paper before, and its been fine, so i'm stuck! should i go buy expensive hp paper? download a new update or something?! help!!