C6500 Fuser issues

[AyJayAreDii]

I have a Pro C6500 which has the "FIXING DRIVE GEAR /F 20T 28T" A03U808600 lossing its teeth once per fortnight. The fuser has been fully serviced and all gears, sleeves, bearing etc replaced. We are also getting scratch marks on the prints from SRa3 paper buckling on the Fuser entrance guide.

KM tech support just told me to replace the gear and should be fine... 28 gears and two PMs later and still having this problems.

Any idea what is going on and if there two problems could be related. like the fuser starting to turn a bit to late? in which case is there a way for setting the fuser start time?

[Gamut]

Just a stab in the dark, have you replaced the torque limiter located on underside of fixing unit?.

[nking58]

Just a stab in the dark, have you replaced the torque limiter located on underside of fixing unit?.

+1
i would also check lower roller insulating sleeves and the 1-way gears(there are 3 of them), there is a bulletin on those and i believe there is an updated frame piece on the drive side of the fuse.

[AyJayAreDii]

+1
i would also check lower roller insulating sleeves and the 1-way gears(there are 3 of them), there is a bulletin on those and i believe there is an updated frame piece on the drive side of the fuse.

all 3 been replaced and even the shafts as they seemed a little warn. also torque limiter has been replaced. have fitted the mod for the gear assembly on the drive section of the fuser.

[seniortech]

Is your customer running out of spec (over 300g) card? I have replaced loads of broken fixing gears because of customers doing this...

[AyJayAreDii]

Is your customer running out of spec (over 300g) card? I have replaced loads of broken fixing gears because of customers doing this...

Yep they use 350gsm and no matter what we say, there company director is our company director. Short of replacing the machine with a "press 8000"? i think this is going to have to continue with the weekly gear replacement.

[kronical]

Yep they use 350gsm and no matter what we say, there company director is our company director. Short of replacing the machine with a "press 8000"? i think this is going to have to continue with the weekly gear replacement.

Well there ya go. They have specs for a reason...

[Stirton.M]

Kind of hard to tell the boss what the maximum specifications are, but personally, I would stand my ground on the issue. If the customer want's to abuse the machine, I am going to charge them for damages. Your director, dunno what that equates to here, should NOT be dictating to allow the end user to abuse the machine beyond specs. I would lodge a complaint to technical support if that happened. Thankfully, our service manager has no tolerance to pushing the machine beyond specification and will allow us to charge for repairs if it is found the end user was abusing the specs. What you are dealing with is tantamount to a nuisance customer. I have one of those here. He insists on pushing 300gsm through the duplex, in spite of the numerous times I, and the other techs who work on that series, have told him from day one, not to do. Now he is having duplex problems almost every other week and we charge him for repairs every other week. Eventually he will get the point when the bills start adding up.

That said....the gear breaking may not be a result of the paper being ran.

Beside the gear you say is being broken, check the torrington gear that drives that upper belt rollers and ensure it is traveling the correct direction relative to the paper feed. Not 100% likely, but then again....

Also, there is a known issue regarding the gearbox....

1. One of the gears in the fusing unit gearboxfails. The shaft for fusing unit gear/H has been changed so that it is now supported at both ends instead of just
one end. The gear is now made of a stronger material.
The new design has been incorporated into all bizhub PRO C6500/C6500P machines beginning with s/n A03U010000787. A replacement gearbox is
available for machines with lower serial numbers. For the machines with serial numbers between A03U010000788 and A03U010001446 the fuser gearbox is
already updated and only fusing gear/H (p/n A03U 8088 11) needs to be replaced.

The gear made of a stronger material...that would be steel.

also

A one-way gear (p/n A03U 8093 00) is slipping in the fixing drive assembly.
Replace the (3) fixing drive gears with the modifiedFixing Drive Gear/M 22T (p/n A03U 8093 11) andthe fixing drive shaft/A (p/n A03U 7258 00).

and

CAUSE: Teeth on Fusing Drive Gear /F (20T/28T) are breaking. Fixing Drive Gear /O (26T) is installed backwards.
SOLUTION: Replace Fusing Drive Gear /F (p/n A03U 8086 00) and Fixing Drive Gear /O (p/n A03U 8095 00) ensuring that both gears are installed correctly.

That Gear /O is my first suspicion. That is the big green gear. It can only be installed one way. To know if it is or not, the gear sides are different, one side has an indentation. That indentation should be facing towards the mainbody of the fuser unit, where there is a C-clip on that shaft. Installing it backwards can cause too much resistance to normal movement and it will damage the gear you are talking about, and sometimes the green gear.