unknown

asked Jul 24, 2003 at 9:09am
Hp HP LaserJet 4M

Paper jam from bottom tray only on LaserJet 4M+

The printer is an HP LaserJet 4M+. It works great if you feed from the manual feed tray. If you try to feed from the lower tray, the paper is picked up and goes up about an inch into the printer (I can see it appear in the manual feed tray area, if I look through the gap at the bottom). Then it stops and the printer gives a 13 PAPER JAM error. The problem just started occurring today; I'm told it started after the lower tray ran out of paper and was reloaded.

Here's what I've done so far: The oblong pickup roller for the tray is practically new, having been replaced only a month ago, and I assume it's not the problem since the paper makes it up into the printer. I checked the flag that hangs down into the tray area, making sure it was still in place and moved freely. I blew out the optical sensor area for the flag, as well as the slot area the paper feeds into. I removed the toner cartridge and checked for paper jammed in that area, and found it clean.

Any other suggestions?
Just after the pickup roller, there is a small secondary feed roller. That roller tends to slip on the shaft and the other driven end slides off the drive. The way to cure it without disassembly is to get a small screwdriver and pry the rubber at the end. Turn the roller and gradually work the rubber down the shaft till there is almost no play in it.
by moe on Jul 24, 2003 at 9:17am Add comment
I checked the little roller and it turns freely in one direction, but not in the other. Is that normal? It doesn't look like it's slipped off its shaft. It's very shiney and worn-looking, but it doesn't seem like that would cause a sudden change from working reliably to not working at all.
by unknown on Jul 24, 2003 at 9:30am Add comment
Moe - this secondary roller that you are referring to please - I can see on my loewr cassette feeder that just in front of the d shaped pickup roller is a piece with a black square top, and two small white rollers beneath them - is this the part you are referring to?
Your advice appreciated
Ian
by unknown on Jul 25, 2003 at 2:59pm Add comment
If you hold the roller and move it side to side, it should only move about 1mm. If you get about 2-3mm of movement that would be enough to cause it not to turn as the gear on the other end comes off the drive gear. The roller should spin easily clockwise and have resistance the other way.
Ian, I think you're referring to a 4ML or a 4MP. This thread is for a 4M+, totally different printer.
by moe on Jul 25, 2003 at 6:31pm Add comment
Moe - thanks for your remarks - I do understand that it is for a 4M Plus, and not a 4L or 4P.
I got confused about which tray David meant. When her said Lower tray, I assumed he was referring to a 500 sheet lower tray which as you know can be added to the printer for extra capacity sheets. Taking another look at the thread, I see he means the PC tray as it is correctly called with this printer.
By the way, if there is more than about 1mm play in the pickup roller, would this mean that the whole pickup assembly would have to be taken out and repaired or replaced?
Thanks
ian
by unknown on Jul 26, 2003 at 3:05am Add comment
David, I took another look at the post and it might be a small scrap of paper or something else in the paper path blocking the paper from going upward. I once was on site and had a similar problem. Turns out a large waterbug happened to be in the wrong place when someone sent a print job. The pickup roller squished him and bug guts got into the paper path. I use a thin 3X12 inch piece of flexible plasti to clear the paper path. Push it up from underneath and work it up and down along the path till whatever is blocking it pops out. Saves a bit of dismantling.
Ian, I was only referring to the small rubber drive roller when I mentioned the play. The pickup roller doesn't matter unless the shaft it's on is physically broken.
by moe on Jul 26, 2003 at 7:54pm Add comment
Moe - thanks for this clarification.Ian
by unknown on Jul 27, 2003 at 1:39am Add comment