unknownasked Nov 29, 2002 at 9:12am
HP 4050 Duplexer
Remove the bed.
That will expose the 2 rollers. Clean them up with rejuvenator or whatever.
Replace the bed and the 6 screws.
Now prise off the cover with the power plug (it's difficult, but it will come off), underneath you will find the gearing.
The gearing is tensioned by a spring clip on the large gear. Remove the clip, E-clip and the large gear wheel.
Squeeze the clip to re-tension it. Replace the clip, the E-clip and the gear, replace the side cover and run the duplexer.
Oh, I hate duplexer's. Too fiddley.
> I can now guarantee that my duplexer is 100\%
> operational, I fixed the problem by using Trev Pearson's
> suggestion, I would like you to post on FYOP on my behalf to
> thank Trev for that post even thought i wasnt for me but it did
> I would like you to post it in the forum, they would listen to
> you and also say in there that I am truly sorry.
So I followed your directions about tightening the clip that provides friction to the big gear, I've printed about 1000 duplex pages so far, and no jams. And I don't get that nasty clunk sound on page feeds through the duplexer.
I print the books I sell and was out of inventory. I thank you and my customers thank you.
For at 2 page document, page 2 prints fine. the sheet goes all the way into the duplexer and gets stuck after that - when it's being pulled back through the duplexer so it can re-enter the printer. When I looked at the position of the sheet when the error occurred, the top edge was about 2 inches before the rollers. (I can send a photo if that would help)
I can't seem to find the rollers responsible for pulling/pushing the paper through so the 2nd side can be printed. There are 4 white plastic rollers under the green page diverter thing; are they the cause of my problem? Is this problem even roller-related?
Also, why is it printing page 2 first and not page 1? (I would guess this is how it's done so the pages are properly arranged in the output bin)
I have taken the duplexer apart. I quickly tried to disconnect the electrical plug on the right side cover so that I am able to see the gears as the printer is working. However, I wasn't able to connect the duplexer and see the gears at the same time.
Some more questions.
1) Is there a roller wheel deep inside duplexer (hidden)? If there is, has anyone replaced it?
2) Is the small, metal (brass colored) gear the motor?
3) Depending on which way I rotate the brass gear, the big white gear (with the spring clip) will move and engage one or another gear. However, no matter which way I manually rotate the brass gear, the front roller wheels rotate in the same direction (although much easier in one direction). Should reversing the direction of the brass gear also reverse the direction of the entire gear system? Can anyone send a photo or diagram of all the gears and which direction they should rotate?
4) What do those fine hairs do? They are located near the front of the green part and go across the paper path.
FYI, if you lose the e-clip like I did when taking it off, you can bend a paperclip to work... at least for one print ;-) We'll see how it goes once the user starts using the duplexer full-time!
Trev's suggestion still works in 2017 -- The tension-er on the big gear seems to work for me
I have only a few test pages so far -- but it is better than what I was getting before (every single piece jammed )