Patent ID: 8243885

Claim:
An X-ray generator comprising: a rotary anticathode having an anticathode part to generate an X-ray by collision of thermal electrons, and a shaft part provided coaxially with the rotary anticathode part; an anticathode accommodating case having an air-tight case for maintaining a periphery of the anticathode part to a vacuum atmosphere, and a journaling case part for rotatably supporting the shaft part via a bearing; an electric motor that rotatingly drives the rotary anticathode, and a cooled jacket through which a cooling water is flown for cooling the anticathode part and the shaft part, provided inside of the rotary anticathode, wherein an insulating bearing is used as the bearing, with at least one of an inner ring, an outer ring, and a rolling element of the insulating bearing being made of an insulating material, a conductive fiber brush, having a plurality of conductive microfibers serving as a slide-contacting brush, is arranged between the anticathode accommodating case and the rotary anticathode, so that current is flown from the rotary anticathode to the anticathode accommodating case via the conductive fiber brush, and each of the conductive microfibers is formed of a conductive fine filament made by bonding a plurality of micron-sized microfibers made by carbonizing an acrylic fiber with copper sulfide.