A postage meter includes a printing device, for example an inkjet print head cartridge having an integral ink supply, removable from the postage meter by a user of the postage meter whereby a cartridge with a depleted ink supply can be replaced with a cartridge having a full ink supply. The printing device includes means storing a unique identification of the printing device. The postage meter includes reading means to read the unique identification of a printing device installed in the postage meter to determine from whether the printing device is authorized for use in the postage meter. The postage meter is operable to print postage indicia only if the printing device is authorized for use in the postage meter.