Method for detecting condition of nozzle member

1. A method for detecting a condition of a nozzle member of a multi-nozzle type component mounting head, the method comprising:

providing the multi-nozzle type component mounting head, the multi-nozzle type component mounting head including:

a plurality of nozzle members having movable parts respectively movable vertically and linearly arranged in a direction crossing a direction of the vertical movement, and nozzles, for holding components, connected to lower ends of the movable parts, respectively;

a nozzle moving apparatus for vertically moving each of the plurality of nozzle members individually;

a height detector for detecting vertical positions of the movable parts of the plurality of nozzle members;

a light projector provided on a straight line on which the plurality of nozzle members are arranged and on opposite sides of the nozzles;

a light receiver for receiving light from the light projector; and

a load cell for outputting an output signal in accordance with a pressing strength of one of the nozzles by being pressed by the one of the nozzles,

wherein the one of the nozzles can escape upward in a case when a tip part of the one of the nozzles is urged downward and pressed to an upper side;

moving the plurality of nozzle members by the nozzle moving apparatus so that all of the nozzles retreat in an upper side of an optical path, and making the light receiver receive the light from the light projector without intercepting the light therefrom;

moving, using the nozzle moving apparatus, an arbitrary one of the plurality of nozzle members to descend so that a tip part of the nozzle of the arbitrary one of the plurality of nozzle members intercepts the light projected by the light projector and shields the light receiver from receiving the light projected by the light projector;

detecting, using the height detector, a position of the arbitrary one of the plurality of nozzle members by measuring a vertical directional position of the movable part of the arbitrary one of the plurality of nozzle members connected to the nozzle of the arbitrary one of the plurality of nozzle members, at a timing when the light receiver detects that light reception and light shielding from the light projected by the light projector are switched by the tip part of the nozzle of the arbitrary one of the plurality of nozzle members;

repeating descent and detection for all of the plurality of nozzle members existing between the light projector and light receiver, and detecting the positions of all of the plurality of nozzle members; and

storing, as reference positional information, information on a vertical position from the height detector at a timing when the light receiver detects that shielding of the light from the light projector is switched for each of the nozzles without performing an operation of holding a component;

storing, as inspection positional information, information of a vertical position from the height detector at a timing when the light receiver detects that shielding of the light from the light projector is switched for the each of the nozzles while performing an operation of holding the component;

calculating a nozzle moving amount when the one of the nozzles takes out the component, a nozzle moving amount for mounting, on a substrate, the component held by the one of the nozzles, and a thickness of the component held by the one of the nozzles, based on the reference positional information and the inspectional positional information; and

measuring, using the height detector, information on a vertical position of the one of the nozzles at a timing when reception and shielding of the light are switched by the one of the nozzles after the one of the nozzles is made to descend to the substrate for mounting, on the substrate, the component held by the one of the nozzles,

wherein when the difference between the measured vertical position of the one of the nozzles and the reference positional information of the one of the nozzles is equal to or greater than a determined value and the measured vertical position of the one of the nozzles is at a lower level position than the reference positional information, it is determined that the one of the nozzles is pressed against the load cell and an output value of the load cell is measured, and

wherein when the difference between a previously stored output value from the load cell and the output value from the load cell is not within a prescribed range, it is determined that the escape of the one of the nozzles does not function.