| 摘要 |
PURPOSE:To measure the quantity of charges of a toner by a simple method with high accuracy by using a magnet having a prescribed shape so as to retain a developer in a magnetic brush developing system. CONSTITUTION:A magnet 8 retaining a developer is formed into a 2-step shape having a central protruded part, and a sample developer 9 is stuck to the inner pro- truded magnet face. In this magnet 8, magnetic poles of the same polarity are adjacent to each other, and lines 10' of magnetic force at each upper-step edge rise vertically by mutual repulsion. Accordingly, when a high-pressure gas is sprayed on such a magnetic brush, no developer 9 overflows the sample face of the magnet owing to waving. |
