unknown

asked Feb 27, 2003 at 7:56am
Hp HP LaserJet 4M

HP Laserjet 4M clunking noise/paper jam

Just when I was starting to like this old printer, after replacing the fuser bulb and generally cleaning the unit a few weeks back, it dies. When I powered it up, this morning, it made a really nasty clunking sound. Before that moment, it had always been as quiet as the unit's fan allows. Now, when I try to print, the noise cycles about every second and the paper jams up right at the entrance to the exit paper feed. Printing appears to be complete, but the paper can't exit the printer.

Any ideas?
Does it jam going into the fuser or coming out of the fuser? It sounds like you may have a broken coupling gear.
by david belton on Feb 27, 2003 at 8:24am Add comment
Coming out. The rollers at the top of the printer, external where the paper exists the printer, don't move at all. When the printer is warming up, there is a light "thunk, thunk" sound that happens on pretty close to one second intervals.
by unknown on Feb 27, 2003 at 9:31am Add comment
I'd be more inclined to blame missing teeth on the fuser heat roller gear at that interval. You can open the back door, and remove the 2 hex-headed screws that hold the fuser assembly. Carefully slide it back to avoid breaking the arm sticking up on the right side. You can then turn the gear and look down at the end of the heat roller and observe the teeth on the large gear going around it. We have the gears and an instructional video for replacement. Be careful when you have the fuser out to not touch the heat roller, especially if the printer has been on for awhile.
by moe on Feb 27, 2003 at 9:54am Add comment
If you can't find a broken/damaged gear, or other visable problem, you might want to actually remove the "Paper Exit Assy". I remove 5 or 6 assy's every year, that just need cleaning and lubrication to get the exit rollers turning again properly. The biggest problem is with that top roller assy, that you can see not turning. More often you are likely to see this roller stall, or turn more in a jerking type motion. Usually as paper just starts to get to this roller, or enter this roller, it will stall and a jam will occur. There are bushings on each end of this shaft with the roller attached. These bushings get almost clogged with dust and dirt that is attracted to the lubrication inside them. Over time the build-up becomes so thick that it makes the roller turn slower and eventually stops it from turning at all. By cleaning out the bushings, lubricating them litely and cleaning off the ends of the shafts [that the bushings slip over], you will correct this problem. While you have the exit assy removed, inspect it closely and also clean the rubber rollers/tires and complete assy for best results....HOWEVER, TO BE HONEST: I can't remember any "unusual noises" coming from the exit section, except paper jamming/stalling noises. At least by removing the exit assy you can also inspect the gears and drive mechanisms attached to it...Good Luck! Denny Conway
by Denny Conway on Feb 27, 2003 at 4:36pm Add comment
Here's what I've found, so far. The large idler gear (probably the "fuser heat roller gear"?) that is situated around the fuser bulb is shattered into several pieces. The other two gears appear to be fine.

The chassis-mounted gear that the top gear from the fuser-mounted trio drives seems to be limited in its movement. Maybe that is what broke the fuser gear? I can get that gear to turn about 1 1/2 times and it stops against something. It will turn freely in both directions about the same number of cycles and stops. I tried to get the top cover off, to look at the mechanism, but it appears to be stuck on the front side.

At the minimum, I need that gear. Thanks for the help that took me this far.
by unknown on Feb 27, 2003 at 6:10pm Add comment
You're bumping up into toner cartridge resistance. Easy way to tell if that gear is broken is to pull the toner cartridge and turn the large gear on the right with your thumb. This will turn the whole gear train and allow you to check the coupler gear. Sometimes both gears break. If you need either gear and the instructional video that accompanies it, let me know. We have the coupler gear as an HP4 Fuser Jam Kit. The other gear comes as a custom kit, different video.
by moe on Feb 27, 2003 at 10:34pm Add comment
No, this resistance is happening without the cartridge installed. Turning the mechanism from that right side gear, does show me that a metal bracket at the back of the printer drops down about the time the resistance appears. However, the resistance is present turning the gear in either direction. With my fingers, I absolutely can not turn the gear past that point. I haven't seen any other signs of broken gears, though.

I don't think I need any additional instruction to replace the broken gear on the fuser. However, if you think there is something inside the printer hanging up the drive train, that is probably the kit and video I do need. Can I buy the fuser gear alone?
by Tom on Mar 1, 2003 at 8:25am Add comment
That coupler gear usually won't cause binding like you're saying you get when you turn the gear train. Could be another gear in the assembly gone bad. I've seen the gear that turns the coupler gear go bad a few times. We stock that as well. You won't be able to tell unless you pull the assembly out and examine it.
by moe on Mar 1, 2003 at 3:07pm Add comment
I guess the real question is, "should I be able to turn those gears (with my fingers) an infinite number of times?" I can't turn a similar gear on my HP 5P at all.

Maybe I'm overestimating the problem, but it looks like getting into the main geartrain might be a larger task than the printer is worth. But I could be wrong about that, too.

Can I buy the one known broken gear and, if so, how much will it cost and how do I go about getting it ordered?

thanks,
Tom
by Tom on Mar 2, 2003 at 8:01am Add comment
That's why we include a video with the coupling gear. If you want the other gear, email me.
by moe on Mar 2, 2003 at 10:19am Add comment
Moe,

The "HP LaserJet 4/4+/5 Fuser Jam Repair Kit" doesn't seem to address the problem of my printer. The website describes this kit "Problem: Paper jams at fuser, and there is a clicking or crunching sound while the printer is running."

My printer was getting pages out of the fuser assembly, but the paper stopped when the page is about to exit the top of the printer. Does this kit still make sense for that problem? I have your "Fuser Repair Video" and I used it to disassemble the fuser mechanism and locate the fuser gear that's now broken. But I don't think that was the original problem. I think whatever is hanging up the gear following the fuser stressed the fuser gear.
by Tom on Mar 7, 2003 at 7:19am Add comment
Those gears break from a combination of heat and stress. We have them in stock. Since you already have the video, you can just get the gear. That gear also drives the exit assembly so it should fix both problems.
by moe on Mar 7, 2003 at 9:26am Add comment