Patent ID: 7388561

Claim:
A characteristic adjustment apparatus for an image forming apparatus that is provided with a multi-electron source in which a plurality of electron-emitting devices are electrically connected by wiring and arranged on a substrate and a fluorescent member for emitting light by irradiation of an electron beam, comprising: at least one or more luminance measurement apparatus that is capable of, in the case where a display portion of said image forming apparatus is divided into a plurality of areas, measuring luminance of electron-emitting devices of the entire one area among the plurality of areas without moving; a control circuit for calculating a characteristic shift voltage to be applied to said electron-emitting devices based on a relationship between a drive voltage applied to said electron-emitting devices and luminance measured by said luminance measurement apparatus, the characteristic shift voltage being larger than a voltage applied to said electron-emitting devices for forming an image; and applying means for applying said characteristic shift voltage to said electron-emitting devices so as to shift an emission current characteristics of said electron-emitting devices.