| 摘要 |
<p>PURPOSE:To increase image density by specifying the degree of magnetization of the magnetic carrier particle and the thickness of the developer layer supporting by the developer supporting member. CONSTITUTION:The thickness of the developer layer 27 is controlled by the blade 24 so that the height of the magnetic blush, namely the thickness of the developer layer on the sleeve in the developing area is thinner that the gap between the sleeve 22 and the photosensitive drum 3 closely facing each other in the developing area. Then, the image having satisfactory density can be obtained even in the case of non-contact developing, provided that the density of bristles of the magnetic blush on the sleeve in the developing area is made >=6 of bristles/mm<2>. Furthermore, in order to make the density of bristles of the magnetic blush on the sleeve in the developing area >=6 bristles, the magnetic carrier particle having the degree of magnetization per unit volume sigmad, in the magnetic flux having the same value as the peak value of the flux density on the sleeve surface of the magnetic flux formed by the developing magnetic poles, being <=100emu/cm<3>, should be used as the magnetic carrier particle.</p> |
