Acting on a tip from Fisher (p4p member), I placed a SP3500N laser printer, bought a MICR cartridge from Rosetta Technologies and made our own check printer. All wnet well until the Rosetta cartridge did not fit in the SP3500N.
In the past, I've had a lot of experience with rebuilding HP, Lexmark & Xerox cartridges. I examined both the OEM and Rosetta, they looked almost identical except for a small nub on the Rosetta cartridge. On the Ricoh cartridge there was no nub. This nub prevented the Rosetta cartridge from inserting all of the way into the SP3500N, luckily that extra nub was screwed onto the Rosetta cartridge. I removed the screw, off came the bub and presto chango the Rosetta cartridge fit perfectly and printed fine.
I have the pictures on my cell, will try and upload them over the weekend for everyone.