9050 unexpected paper size error

[sharpie]

I have a LJ9050 with 2K sheet paper drawer that errors with unexpected paper size only when duplexing from tray 4. all simplex pages run fine. all other trays duplex fine. I have changed the paper size sensing board and 1st feed assembly in tray 4. we changed out the duplex unit with customers other machine and same error. config sheet shows proper paper size for the trays. Can anyone shed some light on this?

Thanks

[theengel]

^{Does it give this error EVERY time you duplex from tray 4, or is it intermittent? It does this on the paper path test from the control panel?}

[sharpie]

The error occurs every time we duplex from tray 4, including in the paper path test mode.

[theengel]

Does it give the error while printing to the front side or back?

[Wild Bill]

I had a bad standard/custom switch cause problems cant remember if it threw that code

[sharpie]

It throws the code after the first side is printed. The printer will eject the paper after being opened and closed for jam removal "checking printer, clearing paper path". We never get an error doing one sided pages from tray 4. We never get a jam or error duplexing from the other trays. Do you know if there is a different timing threshold for paper size sensing when simplex printing vs duplex? It seems like that might be a formatter issue, and that is probably my next move, to replace the formatter but the customer is becoming anxious to get this resolved and I don't charge the customer for things that don't fix their problems so I want to be confident that my investment will resolve the issue.

[theengel]

Wild Bill's suggestion was the direction I was thinking. Mainly because I was thinking that if tray 4 size is used for a different paper size, maybe that's it. This might also trip other sensors throughout the machine that ordinarily wouldn't be tripped--if you're using tray 4 for larger paper. I once had a machine that had rollers that were so worn, that when printing to a larger paper size it would jam, because the roller surface was moving just slightly slower--which means the machine would only pick up jams from larger paper, as they spent more time on that roller.

Also: I can't remember what the 9050 has on it, but this could be sort of the same issue just described. If you have an exit roller that carries paper down to the duplexer, check that. I've seen those rollers that are shaped like thread spools, where the middle of the roller has a smaller diameter than the outer edges. Then there are free spinning rollers that ride against them, but they are loaded on metal springs. If the springs are pushing too tightly, it changes the diameter of the roller, because the paper rides right up against the smaller part. So you get jams on larger paper sizes. The easiest fix is to pull the spring back a little and make it looser.

I would also check the paper itself. I once had a cust who cut their own paper, and the machine would only detect the wrong size when duplexing.

I'm sure you checked all this and tried a different size paper, but I'm just telling you where my thoughts are.

But after this, I would probably move toward the formatter.

[BulletDavid]

Do we have the final solution answer to this inquiry ?