Method for Pre-Sizing Copier Magnetic Brush Shells
Original Publication Date: 1982-Jun-01
Included in the Prior Art Database: 2005-Feb-09
An extruded piece of aluminum tubing may be used as the shell of a magnetic brush in a copier. The run-out of the aluminum tubing must be held to a very tight tolerance. (Run-out refers to surface variation of the tubing as the tubing is rotated). In the past, the tubing was extruded and then machined to the desired outside diameter tolerance and straightness. The difficulty arises in that machining to the desired outside diameter reduces the depth of grooves in the outside surface of the tubing. The grooves are put in the tubing when the tubing is extruded. The process described herein solves this problem by extruding the tube at a diameter slightly larger than required and then shaping the tube to the desired straightness and circularity (run-out) in a compression die.