Patent ID: 6636706
Filing Date: 2003-10-21
Classification: G03G

Abstract:
A detection unit for outputting an electrical signal in accordance with an electrostatic capacitance to an apparatus main body in order to detect a residual amount of developer in a developer vessel by an electrophotographic image forming apparatus main body, comprising:a measurement electrode member which is arranged at a position where said measurement electrode member contacts the developer when mounted in the developer vessel, has at least a pair of portions parallel to each other at a predetermined interval, and has an input electrode for receiving a voltage from the apparatus main body and an output electrode for outputting an electrical signal in accordance with an electrostatic capacitance generated upon application of the voltage; a reference electrode member which is arranged at a position where said reference electrode member does not contact the developer when mounted in the developer vessel, has at least a pair of portions parallel to each other at a predetermined interval, and has an input electrode for receiving a voltage from the apparatus main body and an output electrode for outputting an electrical signal in accordance with an electrostatic capacitance generated upon application of the voltage; an adhesion member to which said measurement electrode member is adhered; a lid member which is coupled to said adhesion member and covers said reference electrode member interposed between said adhesion member and said lid member; and an engaging portion which engages with a vessel positioning portion attached to the developer vessel when said detection unit is attached to the developer vessel, and positions said detection unit with respect to the developer vessel.