C450 Duplex jam issue.

[AJ058]

C450 only Jams when duplexing. Very consistant.
May be a broken tab, but have yet to identify where.
fist page seems to clear, then second page jams in the duplex unit.
first page just entering the finisher path shute.
Customer had a very bad multi page Jam, they yanked the paper out, ripping it out in pieces.
Had to clear out many small pieces of paper right below the K IU.
Also found a small black u shaped tab about the size of pencil eraser end.
toward the back of the machine under the K IU,
can't figure out if it came from the C450 or is a foriegn part.

When the duplexing starts it makes a racheting or clicking sound like it is skipping gears.
then it jams.
It workd OK without duplexing.
At first it seemed to only jam when duplexing from the top paper drawer

Where should I start looking for the problem?
Can an adjustment be made to correct the problem?
If I can't identify what is damaged,
what would you recommend replacing first?

Thanks for everyones help.

AJ

[Stirton.M]

If it runs ok in single sided but fails duplex, it can be several places where the jam is occurring. A big help would be to review what the jam code generated at the time of the jam is. You can use that to reference which item is causing the jam.

From a little of your description....paper leaves the tray, goes up the vertical transport and across the sync/transfer section and into the fuser. It exits the fuser and a switchback is initiated which reverses the paper when it fully exits the fuser to shift it back towards the duplex entrance guide and returns the paper through the transfer section. The ratchet sound you are hearing is the gears trying to drive the paper back. There is a while lever that has a spring on it that holds tension on the gear of that lever and presses it towards the drive. If the spring clip is broken on the lever or the lever is warped, proper gear mesh is unobtainable and it makes that gawdawful noise.

It is one place to look at least for that particular problem. Again, the jam event code is an important clue to help narrow down which sensor is triggering the jam if you are still getting one after making sure the previous item I talked about is dealt with.

[RRodgers]

I've see the accuator hang up in the duplexer sometimes. Be sure it moves freely.

[AJ058]

Jam event code is 3201 using 2nd paper tray

AJ

[Stirton.M]

There is possible damage to the fuser unit drive gears according to that code. It is specifically indicating the drive motor failure to turn. Again, this may be what I described eariler. If you eliminated that through a visual check, then you need to inspect the fuser drive.

To check, you need to remove the unit.

Turn off power and unplug machine.

If there is a finisher on the machine, remove the horizontal transport section of the finisher to expose the exit tray of the main body. On the left side of the main body, there are two screws which hold this tray in. Remove them and you will see the PSU. On the right side near the front of the unit, behind the toner bottles, is a heavy wire set of connectors that run towards the fusing unit. Unplug those and unclip the harness clip.

While looking at the fusing unit straight on, on the left side (front area of main body) just above the fuser is a small plastic cover with a single screw. Remove that cover. Behind that is a connector harness that runs from the fuser to the connector in the vertical post there. Disconnect that.

Under the fuser unit are two screws that hold the unit in. remove them. The fuser should now easily be removed from the machine. Be careful, it may be hot.

Inspect the drive gears on the rear side where they mate up with the fuser, as well as the fuser. The gears there may be damaged or heavily worn. Inspect the drive shafts and make sure they are firm. If they wiggle, the drive mechanism may be damaged and needs to be replaced.

[AJ058]

Gears all seem fine, a couple tabs that broke off came from the cover panal below tab marked M-2.
The question is what appears to be two accurators--- on either side going to back gears, white on right or back of machine, black on left or front of machine.
They have a spring wrapped around them. They are both loose and gear they conrct to moves easily back and forth about a 1/4 turn then tightens, will not move 360.
Is this normal?
If it is, what would you look for next?

Thanks for the help.

AJ