Strange paper feeding issue

[vincent64]

I have this MX-M 620 with a bit of a strange one, when feeding paper through it, in the 8.5x11r direction, it will dog-ear the lead edge corner of the paper on the front side of mach. when exiting into the center cavity, it also does it on 8.5x14 as well, kinda figures, mach has the large LCC on it, so they can run 8.5x11r from that LCC.
Now for the strange part, it does not dog-ear or even catch 8.5x11 running through it, no nick, tear, catch mark on the paper, just runs it with no prob.
Mach has 275K on it, I just re-built the fuser, rollers had wear marks at the sep-fingers, thinking this was the cause, nope, took the exit unit out, gave it a good going over, could not find a burr, or nick on any guides in there....any ideas???

[blackcat4866]

How about paper cuts in the doors & guides? Since it affects the 8 1/2" width prints but not the 11" width documents there is clearly a snag somewhere. =^..^=

[Hemlock]

Agreeing with Blackcat. Remember, if the dog ear is flattened, it's pre-fuser. If it's just a bend, it's occuring post fuser.

[vincent64]

Well I agree, there is a snag or burrr somewhere in the delivery unit, the one just above the fuser, but I had it out and apart as far as the fan leads would go, and felt no roughness or cuts, now I do seem to recall that part of the tandom tray and the LCC take the same feed path through the machine, the right side, the left takes a slight different path, of the tandom tray that is.
I am hoping we have a delivery unit from a old mach to try out on it.
And its not flattend, just a bit a curl on the front frame side.

[blackcat4866]

... post fuser, then. Is there a finisher? What happens when you remove it? =^..^=

[vincent64]

... post fuser, then. Is there a finisher? What happens when you remove it? =^..^=
I had the paper exit into the cavity of the machine, by-passing the finisher, and still does it, going to try to get by there today if posible, we all know how that goes.

[Toner Boy]

We had a similar problem with an MX-3501 where the edge of the paper was riding on one of the reverse gate ribs (post fuser) and would miss the rib 70% of the time causing dog ears or 'flipped' corners. This problem was resolved by changing the paper cassettes, thus adjusting the beginning position of paper feed F to R by the slightest amount, enough to permanently resolve the issue. Maybe there is a defect in the reverse gate (PGiDM2020FCZZ) or 'left door reverse PG' PGiDM2019FCZZ. You could maybe swap (even from an old AR-M620, they are the same I believe) the assembly, 2 screws and its pretty much done.

[vincent64]

I had a simlar though, checked into it, they are not the same unit, the MX version has 2 of the locking pins in the front, the AR just has 1, also part numbers are different on the whole unit, the gates may be the same.
I am going to have to wait till I get back there, re-check that unit, maybe take some emery paper and just give all the guides a good going over and see what happens.
BTW, thanks ya'll for all the ideas.


We had a similar problem with an MX-3501 where the edge of the paper was riding on one of the reverse gate ribs (post fuser) and would miss the rib 70% of the time causing dog ears or 'flipped' corners. This problem was resolved by changing the paper cassettes, thus adjusting the beginning position of paper feed F to R by the slightest amount, enough to permanently resolve the issue. Maybe there is a defect in the reverse gate (PGiDM2020FCZZ) or 'left door reverse PG' PGiDM2019FCZZ. You could maybe swap (even from an old AR-M620, they are the same I believe) the assembly, 2 screws and its pretty much done.

[Hemlock]

Quick thought: Are all your accessories level and lined up properly?