| 摘要 |
PURPOSE:To obtain a magnetic developer with a large triboelectoric charge quantity by specifying a residual magnetization, coercive force and the range of the magnetic permeability of a magnetic body at 10000 oersted magnetic fields, and by specifying an apparent density, a linseed oil absorption amount and a variable coefficient. CONSTITUTION:In the magnetic developer, the residual magnetization sigmar of the magnetic body at 10000 oersted magnetic fields is in the range of 12<=sigmar<=30 emu/g and the coercive force Hc of the magnetic body at 10000 oersted magnetic fields is in the range of 130<=Hc<=300 oersted and the magnetic permeability is in the ranger of 2.0<=mu<=4.0. Also the magnetic body has 1.2-2.5g/cm<2> of an apparent hardness and 5-30 ml/100g of a linseed oil absorption amount and the variable coefficient of the magnetic body calculated from formula I is 20-50%. In formula I, sigma denates the standard deviation of a partial distribution of the magetic body and X' is the mean particle size mum of the magnetic body. Thus the magnetic developer of a large triboelectric charge quantity is obtained. |
