asked Jul 25, 2009 at 8:34pm
Hp HP LaserJet 4

HP LaserJet 4 Fuser

Hello, I have a HP LJ4. With the fuser removed should the fuser’s gears be easy to turn or should there be a good bit of resistance?

Since trying to work out if that was the cause of the fusing roller gear loosing teeth. I have just fitted another gear.

I have been give another LJ4 with a problem (think it’s toner cartridge related), so took its fuser out to see how easy it was to turn the gears and I can turn the gears easily.

If the fuser gears are meant to turn easy do I need to oil or grease say the ends of the fuser roller that go through the fuser frame?


Should be easy to turn. All you are doing is turning the pressure roller and the metal heat roller. Sometimes they will overtemp and fuse together, making it difficult to turn. There is no lubrication used on the gears.
by moe on Jul 25, 2009 at 10:25pm Add comment
Hi, So how do I fix it so the gears turn easily? The fuser works but I don't want the gear I replaced to end up loosing its teeth.


by djrock on Jul 26, 2009 at 9:22am Add comment
The only resistance in the fuser is the heat roller turning in the bushings. Can't really give any advice on fixing it without being able to see it. If you've replaced the gear, you've had it apart and should be able to disassemble it again and examine everything.
by moe on Jul 26, 2009 at 9:36am Add comment
Hi, OK I will take it apart again. Could maybe what holds the fusing roller in place could be causing the resistance?

I haven’t really stripped the full fuser apart and the service manual does not go into much details. I do have an old broken lj4 fuser so I think I will be stripping it apart to see how everything is held together.


by djrock on Jul 26, 2009 at 10:00am Add comment
Yes the bushings around the hot rollers can cause more friction over years of service. They originally have alittle grease on the ends of them. over time it wears away leaving the metal hot roller to grind away on the bushings. So you could take it apart replace the bushings or clean out the bushings and grease them or just replace. The cost of the fuser is so cheap anymore its hard to justify tearing it down to rebuild. I might be wrong on HP greasing there bushings but I know on most copiers they recommend or require doing it when replacing the hot roller and I do it when replacing broken hot roller gears and it works quite well. Just make sure the grease is made to handle high temps.
by nivek on Jul 27, 2009 at 5:52am Add comment