MP1100 Katana Jam at relay

[Voltage]

Hi Guys

I have a MP1100 that will jam once every 1000 to 2000 copies. This mostly happens on duplex copies. I i look in the plotter jam history, i will have, say 4 jams in a row at 69, then 3 at 115 and the next 5 will be at 19. At the jam at 19, 2 pages will be located in the duplex unit with one just coming out of the duplex say 2-3cm and another one kicked out just before the registration.

Tha machine has about 5.5 million copies on. I does not have a LCT. I have swapped the relay sensor for the bottom trays with the one for pages coming from the LCT. All the paper feed stations have been cleaned . The customer says the problem mostly happens on double-sided.

Any ideas

[Shadow1]

The 19 and 69 are both relay sensor (late and lag) but the 115 seems totally unrelated. I have seen the stepper motors go bad in these machines - most notably the registration motor, but others as well. You can usually feel the "notches" missing (magnet in the rotor degaussed) or the motor seems bound up untill you spin it fast then it freewheels (shorted windings)
Also had "boogers" in the registration assy from lables that peeled

[Ricoh-ono]

There have been several parts updates for the duplex unit to improve reliability.