"The LaserJet III in my office has acquired the annoying habit of shifting its printed output about half an inch down on the paper. This sometimes cuts off the page numbers. It typically will never happen on the first few pages. Once shifted, it stays that way, until I turn it off. I'm kind of clueless, the manual doesn't mention anything like this."
(From: Frank Reid (firstname.lastname@example.org).)
Replace the pickup roller. Clean the transfer rollers with naphtha or mineral spirits. If that doesn't work, replace the transfer assembly (set of metal and rubber rollers after pickup roller; removable by 4 black screws). Inspect the solenoids on the DC power supply: The rubber pads sometimes become sticky and hold onto the armatures, thus messing-up the timing. If that happens, scrape the old pad off, clean the armature and core with solvent, and replace the pad. I use squares of double-sided foam tape and then use naphtha to remove the glue from the outer side. If you remove the old pads but don't replace them, the printer will be more noisy, and permanent magnetism in the solenoid cores may affect timing.
(From: Joop van der Velden (email@example.com.NL.net).)
Two possibilities: a mechanical problem with the paper transport, or a escape sequence reprogramming the printer paper format(ting)
Try to print some test pages from the printer itself (no pc connected) If that gives the same problem, try cleaning the paper path and transport an paper separation mechanism.
(From: Randy McVittie (firstname.lastname@example.org).)
I thought it might have been the pick-up roller, at least that is what the manual was pointing me towards, but other people's 2 cents worth said to look at the solenoids SL301 and SL302 on the Paper Control PCA.
There is a piece of foam tape on the core of these solenoids, and it had become kind of sticky, preventing the solenoid from snapping back when power was removed. Then I had severe paper jam problems I guess you need some amount of spacing here. So I put a few layers o of electrical tape in the same spot and now I had great registration. 3 layers of tape was my magic number, your mileage may vary.
This area was not even mentioned as a source of problem in paper registration troubleshooting chart in the HP manual.