| 摘要 |
PURPOSE:To ensure cutting of magnetic brush during pause of operation, and scooping of developer with a simple structure, and to form a color copy superior in reproducibility, by specifying an angle contained by a line joining the center of a developing roll and that of a magnet in the roll and a line joining both centers of this roll and a feed roll just below the developing roll, and an angle contained by this roll center line, and a line joining the center of the feed roll and that of a magnet in that roll. CONSTITUTION:An angle theta1 is assumed by the line joining the center O1 of the developing roll 21 normally rotated and used for yellow color and the center O2 of the feed roll 22 located just below the roll 21 and rotated only at the time of developing, and the line joining the center O1 and that of the magnet 26 of the roll 21. An angle theta2 is assumed by the line O1,O2 and a line joining the center O2 and the center of the magnet 27 of the roll 22. The magnets 26, 27 are arranged so as to satisfy the following equation and inequality: 60 deg.<=theta1<=90 deg., theta2<=90 deg., thus ensuring scooping of the developer at the time of developing, and forming magnetic brush good in form on the roll 21. At the time of nondeveloping, the developer is scooped up, and the remaining developer does not transfer, and cutting of the brush on the roll 21 is securely executed. With respect to other colors, similar operations are executed, permitting color copying superior in reproducibility. |
