I purchased a job lot of Toners for a Ricoh ap3800c for my own use. They are all apparently the right size and shape. Some will fit and work but others do not fit or the Printer complains that the cartridge needs to be reset. I have noticed in the past that some cartridges have slots at the nozzle end to allow the curved spigots in the toner hopper to slide in, some have slot one side only and others have slots both sides. I am confused. I know that some will say 'only buy Genuine Ricoh Toner', well I have the toner now and would like to use it. can anyone throw a light on these variations? Thank you Myrfin.