Patent ID: 7256359

Claim:
A key operation detection unit of an electronic keyboard instrument having a plurality of keys disposed for pivotal movement, comprising: a base plate that is mounted to the electronic keyboard instrument; a mounting portion that is attached to said base plate; a plurality of resilient projections that project from said mounting portion, at least one of the resilient projections corresponding to an associated one of the keys; a plurality of driven portions that are provided at respective one ends of said resilient projections to extend toward the keys, at least one driven portion being depressed when an associated one of the keys is subjected to a depression operation; a plurality of fixed detecting parts that are fixed to said base plate; a plurality of movable detecting parts that are disposed to face respective ones of the fixed detecting parts and are movable toward and away from said base plate; and a plurality of reaction force generators that are provided to correspond to respective ones of the movable detecting parts, each reaction force generator exerting a reaction force to a corresponding one of the driven portions when an associated movable detecting part is brought in contact with said base plate, wherein: each of said fixed detecting parts and a corresponding one of the movable detecting parts facing the fixed detecting part constitute a detector that detects a depression operation of a corresponding one of the keys, at least two detectors are provided for each of the keys, at least two reaction force generators correspond to at least two movable detecting parts of the at least two detectors, and that one of said at least two reaction force generators whose corresponding movable detecting part is brought into contact with said base plate at much later timing in a forward stroke of key depression generates a smaller reaction force.