Feeding device and feeding method of cup-rotated electrostatic spraying system

The invention belongs to the technical field of paint spraying, and provides a feeding device and a feeding method of a cup-rotated electrostatic spraying system. The feeding device of the cup-rotatedelectrostatic spraying system is provided with a cylinder block; the cylinder block is provided with two cavities arranged up and down; the upper cavity is a liquid piston cavity, and the lower cavity is a paint cavity; a metal foil for isolating and closing the liquid piston cavity and the paint cavity is arranged between the two; the metal foil forms a second-grade piston; the metal foil is deformed under the pressure effect to compress the paint cavity; a first-grade piston for compressing liquid in the liquid piston cavity is arranged in the liquid piston cavity; the first-grade piston isprovided with a driving mechanism; the paint cavity is provided with a feed port and a discharge port; and under the effect of the driving mechanism, the first-grade piston moves up and down in the liquid piston cavity for cu