| 摘要 |
PURPOSE:To lessen gear transmission loss in a gear drive device and an image forming device. CONSTITUTION:A plastic molded gear according to the invention includes at least one helical gear G1 furnished with a gate for injection of plastic material upon the bearing boss end-face B on the side not receiving thrust load, wherein the dia. of another bearing boss end-face A receiving the reactive force to the thrust load is greater than the dia. of the first named end-face B. The gears G1, G2 are of helical type, and the thrust force acts thereon so that it is set off, but the thrust itself will remain. |
