MPC6000/7500 Image Fusing jams when duplexing

[Jonza]

Hi,

Have you ever faced a problem where Mpc7500 makes nice 1-sided copies/prints, gives few tens of duplex prints but starts jamming paper to Fusing Unit´s Separator Pawls?
No difference if A4Sef, A4Lef, A3, Palin, Middle Thick, Thick.. and only with 2-sided copies

Problem can be solved by replacing Fusing Unit but thats too expensive part in longer run .

I tried that failing unit in other copier and same thing.
I´ve done so far; replaced Separator Pawl Unit (Stripper Plate) , tried another upper cover (where stripper plate is attached).. still..jams..

Anyone, any ideas?

[herrmann]

How much sheets has the fusing unit run through? Maybe the fusing belt or/and the lower fusing roller are worn, causing paper stick to the roller and push the sheet beneath the separation claws.

[Jonza]

Oh,sorry I forgot to mention it. Copier is quite new; only 110k copies made. Actually I have 3 different cases with same problem. Others have 60k and 450k copies.

Manual tells to adjust the gap between stripper pawls and fusing belt. That was Ok and I don´t feel like the problem is there because if trying that Stripper plate in another Fusing unit; it works, no jams.
I´ve been thinking about the Fusing NIP, is it adjustable in this model? Sp1111-001 stays for Nip Check, haven´t try that, yet.

I took the whole Fusing Unit into parts but visible check gave no ideas. I replaced Oil Supply Roller and it´s Cleaning Roller; they were a little worn out.

[herrmann]

When do the jam occurs during 2 side printing? 1st side or 2nd side?
Does the sheet runs beneath the upper or the lower claws?

[stephend]

Hi,

Have you ever faced a problem where Mpc7500 makes nice 1-sided copies/prints, gives few tens of duplex prints but starts jamming paper to Fusing Unit´s Separator Pawls?
No difference if A4Sef, A4Lef, A3, Palin, Middle Thick, Thick.. and only with 2-sided copies

Problem can be solved by replacing Fusing Unit but thats too expensive part in longer run .

I tried that failing unit in other copier and same thing.
I´ve done so far; replaced Separator Pawl Unit (Stripper Plate) , tried another upper cover (where stripper plate is attached).. still..jams..

Anyone, any ideas?

Had a similar problem with one of my units but was caused by bent stripper plate unit (D0144300). The plate was not visible bent but I was able to determine that the pressure was not even. Maybe was a difference in pressure between the Front Torsion Spring and Rear Torsion Spring - Stripper...I can not tell you because I ordered and replaced all, including the Bracket - Exit Unit. If the fuser is really hot and customer opens to clear a jam and slam it back...could cause a damage that is almost impossible to determine visually. If are well maintained these fusers can last 700K...moment when personally I'm replacing the entire unit because everything is "cooked" inside: harness, lamps connectors are cracked and it's a metal fatigue that can not be stopped.

[Jonza]

When do the jam occurs during 2 side printing? 1st side or 2nd side?
Does the sheet runs beneath the upper or the lower claws?

Jam occurs when first side is coming from duplex unit and second side is printed and is on it´s way to Fusing Unit. And sheet runs beneath the upper claws.

Stephend: "Maybe was a difference in pressure between the Front Torsion Spring and Rear Torsion Spring - Stripper.."
Yup, I was wondering those Torsion Springs, too, but as I mentioned I did try that whole Stripper Unit in another copier where it works real nicely.
By removing covers it is easy to see that jam happening but speed is way too fast.. (75ppm)
Today I made report to our HQ and they might want me to send that failing unit there. I´ll tell you if they find something.
Thanks for help!

[zico21]

We've had a number of MPC6000/7500's have corners catch on the upper stripper "blades" usually the most op-side one, usually on units with relatively low page counts. Usually moving the blade a little closer by turning the adj. screw 1/2 to 1 turn CCW has taken care of it.