| 摘要 |
PURPOSE:To obstruct leakage of electric charge, and to execute a sufficient charge induction by using a magnetic developer obtained by mixing a magnetic toner for showing a resistance value of 10<10>-10<13>pi.cm under an electric field of 10<2>V/cm, and a magnetic particle for showing a resistance value of <=10<6>pi.cm under an electric field of 10<2>V/cm. CONSTITUTION:A magnetic brush developing device 1 has a conductive developing sleeve 2 and a magnetic roller 3, and at the time of development, a roller 3 is driven to rotate at a high speed in the direction as indicated with an arrow (b). On the surface of the sleeve 2, a magnetic developer in which a magnetic particle Mg and a magnetic toner To have been mixed is adsorbed magnetically in the shape of a brush, and carried in the direction as indicated with an arrow (a) at the time of development. When it is being carried, it is slid and rubbed against the surface of zinc oxide photosensitive paper 7 and the development is executed. As for the toner To, that which has a resistance value of 10<10>-10<13> pi.cm under an electric field of 10<2>V/cm is used, and as for the magnetic powder Mg, that which has a resistance value of <=10<6>pi.cm under an electric field of 10<2>V/cm is used. In this way, a leakage of charge in the course of development can be obstructed, and also a sufficient charge induction into the magnetic toner can be executed. |
