Abstract: When a replaceable unit is mounted, a CPU of an image forming apparatus recognizes whether or not a corresponding machine type code and a corresponding country code are stored in a main body NVM. When the corresponding machine type code and the corresponding country code are not stored in the main body NVM, the CPU reads a machine type code and a country code stored in the unit NVM of the mounted replaceable unit from the unit NVM. The CPU stores the machine type code and the country code read from the unit NVM in the corresponding machine type code and the corresponding country code of the main body NVM.

Abstract: When a replaceable unit is mounted, a CPU of an image forming apparatus recognizes whether or not a corresponding machine type code and a corresponding country code are stored in a main body NVM. When the corresponding machine type code and the corresponding country code are not stored in the main body NVM, the CPU reads a machine type code and a country code stored in the unit NVM of the mounted replaceable unit from the unit NVM. The CPU stores the machine type code and the country code read from the unit NVM in the corresponding machine type code and the corresponding country code of the main body NVM.

Abstract: A video data processor disposed in addition to a printer controller includes a video data leading edge sensor for receiving a video signal of characters and objects and attaining therefrom a leading edge of video data, a contour display controller for generating data representing a contour on the basis of the leading edge data, a pattern display controller including pattern storage sections for keeping therein a plurality of display pattern data items and a pattern selector for selecting a predetermined display pattern item from the plural display pattern data items, and a logic circuit for producing a modulated video signal from data outputted from the contour display controller and data created from the pattern display controller and outputting the modulated video signal therefrom. Thanks to this configuration, consecutive dot data can be represented as a regular pattern.