Patent ID: 7694645

Claim:
A rotary atomizing head type coating machine, comprising: a rotary atomizing head to spray supplied paint, an air motor coupled with said rotary atomizing head and rotated by a supply of air, a speed sensor to detect rotational speed of said air motor, an air source to supply an air to said air motor, an electropneumatic converter to adjust an air pressure supplied from said air source according to an electrical quantity, and a controller configured to control an electrical quantity to be output to said electropneumatic converter to diminish a differential between said rotational speed detected by said speed sensor and a given target rotational speed to provide a feedback control of said air pressure, wherein said controller is provided with a steady value computing device configured to compute a necessary value of electrical quantity as a steady value against given settings in arbitrary target rotational speed and paint discharge rate to drive said air motor steadily in a vicinity of said given target rotational speed and at said paint discharge rate; when either said target rotational speed or said paint discharge rate is to be changed, said controller is configured to compute a new steady value on a basis of a changed target rotational speed and paint discharge rate by a use of said steady value computing device, and to output to said electropneumatic converter an electrical quantity on a basis of said changed target rotational speed and paint discharge rate by use of said steady value computing device; said controller further being adapted to output to said electropneumatic converter an electrical quantity for an air pressure higher than that of said new steady value when said target rotational speed is to be changed to a higher speed, to rotate said air motor at a speed higher than a newly set target rotational speed, and an electrical quantity for an air pressure lower than that of said new steady value when said target rotational speed is to be changed to a lower speed, to rotate said air motor at a speed lower than a newly set target rotational speed.