Step motor driving apparatus

A method for operating a driving apparatus including a step motor capable of forward rotating and reverse rotating as a drive source, an operating member connected to the step motor for operation from an initial position to a target position, a link member for connecting the operating member to the step motor, a detecting section for detecting a signal when the operating member comes into a detection zone, and a control section for controlling the operating of the operating member by rotating the step motor, comprising the steps of:

• setting the operating member to the initial position from a mechanically stopped position by forward rotating the step motor at a predetermined step number,
• temporarily reverse rotating the step motor at a time of starting the operation of the operating member from the initial position to move the operating member to the detection zone so that the detecting section may detect the signal when the operating member performs a normal movement,
• forward rotating the step motor in response to said signal so as to move the operating member to the target position, and
• conducting a returning operating to the initial position from the target position by reverse rotating the step motor so as to return the operating member from the target position to the detection zone so that the detecting section may detect the signal, and forward rotate the step motor to move the operating member to the initial position.