Brazilmike

asked Jan 7, 2010 at 12:05pm
Hp HP LaserJet 4

HP4 paper out sensor issue

I just finished replacing the fuser roller of my HP 4. I replaced feed rollers 6 months or so ago. My paper was feeding perfectly prior to the fuser section rebuild. Now it prints beautifully, but when a page is about half-way out of the printer, the next page stops the printer as it begins to leave the fuser section and I get a printer missfeed. I have checked the optical sensor and it seems to be OK. Does anyone have an idea of what the problem is?
check to see if the fuser's paper sensor flag is sticking. a common problem is the sensor flag's mounting/pivot pin (part of the top plastic piece) is broken and the flag is now not working properly.
by seriously on Jan 7, 2010 at 12:37pm Add comment
If you lower the back part of the fuser and look up to the left of the flag, you can see where the end of the arm should mate with the peg. If you wiggle the arm and it wobbles and you can't see the cup end of it with the peg mating into it, then it is broken. You'll have to replace the guide plate the peg is part of. Contact [email protected] and he can help you with a replacement. It won't be until Monday because Moe is off experiencing the colder part of the country.
by Anonymous on Jan 7, 2010 at 2:58pm Add comment
I have already done that and yet the problem persists. The peg is not broken and the sensor flag moves freely but does not wobble. What next?
by Brazilmike on Jan 8, 2010 at 6:18am Add comment
From the way I read your original posting the paper jam issue started after replacing the Fuser. The HP LaserJet 4/4+ Fuser has release levers for the lower pressure roller that have to be in the down position. These are located on the outside of the Fuser frame on each side. - Anonymous
You are correct that I didn't have a paper feed issue prior to rebuilding the fuser, but I don't see the levers you describe. There is a key-type "Lever" that was on the left side of the fuser, positioned over the part that holds the fuser in place, but the video suggested we leave it out upon assembly, which I did. However I put it back in to see if it would correct the feed problem, which it didn't. Any other ideas? Appreciate your responses!!
by Brazilmike on Jan 12, 2010 at 9:58am Add comment
The problems has to be with the optical sensor. If the arm isn't broken, then the actual flag arm on top of the printer is sticking. The arm on the fuser actuates that through a linkage. Here are the photos of the fuser and the optical sensor on top of the printer. http://www.fixyourownprinter.com/reference/guides/sensors/ex
by moe on Jan 12, 2010 at 1:40pm Add comment
The flag arm does appear to stick,but barely. When I print a page, the little guide pin (attached to the flag) where the paper exits the printer is stuck in the up position. But when I barely touch it, it comes down again. The spring in the photos you sent looks right-not stretched. I don't know what to do to alleviate this problem. Any other ideas?
by Brazilmike on Jan 19, 2010 at 11:22am Add comment
If it's sticking, put a little bit of lube on it. Everything depends on precise timing. A fraction of a second will throw it off.
by moe on Jan 19, 2010 at 12:03pm Add comment