JPS6411278A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a toner from being scattered, by constituting the titled device so that a magnetic brush blocks an air current from the upstream side in the carrying direction of a developer carrier, and an air current of the downstream side in the carrying direction becomes a suction current into a developing container in a negative pressure space by a magnetic brush after the development. CONSTITUTION:In an opposed part of a developing roller 4 and a photosensitive drum 1, a developing area is constituted, and in the developing roller 4, a magnetic field forming magnet roller 5 for constituting a magnetic brush is contained, and the magnetic brush in the developing area is napped by prescribed nip width. Also, the magnetic brush napping in the magnetic field blocks an air current from the upstream side in the carrying direction of the developing roller 4, and the air current of the downstream side of the developing area is stabilized. The magnetic brush passed through the developing area is brought into contact with the inner wall surface of a casing 3, and on the upstream side of a contact part, a negative pressure space made out by the magnetic brush, the inner wall surface of the casing 3 and the surface of the developing roller 4 is formed. In such a way, the outside air passes through the opening part of the casing 3 and sucked into the inside of the casing 3, and scattering of a toner can be prevented.