We have a Xerox that has the same problem on and off. Our printer has two blacks. It would recognize one and not the other. The problem is with faulty chips in the toner cartridges. There were also problems with chips in the drums which affected more than just the drums. We even got a few empty toner cartridges. If the same supplier manufactures toner for Ricoh also, this may be the problem. You should probably contact a tech. A sensor may have been shoved out of place, or something else and the tech needs to fix it.
