I have a KM-4530 with a 610 finisher and a BF-1 folder on it and I'm getting J-91.What's happening is the set is coming out of the middle tray of the finisher and every so often the cups/joggers of the folder are right in the way of the set and it hits right on top usually causing a dog ear at the front frame cup/jogger of folder. So far I have tried adjusting side to side home position of both folder and finisher cups/joggers and have ordered folder cups/jogger motor and home position sensor. If that does not work I'm thinking control Brd for folder. Any folder experts out there that have seen this before. Thanks !!

this is not a small job....remove the BF-1. The joggers are run by a motor on the backside of the metal plate the joggers are on. the gear on the motor is a brass center with nylon teeth. the nylon cracks over the metal and caused c-codes and other erratic things. I believe that is the same gear found on the joggers in the DF-600/610/650 as well. That should be the fix. Note watch out for the metal tab that interupts the switch on the back frame of the finisher. It bends easily and the machine won't "see" the BF-1 if it is not aligned properly.

Good Luck

Mark Thanks brass center gear worked