| 摘要 |
A developing method for forming a toner image of high quality which comprises supplying a two-component developer composed of a mixture of magnetic carrier particles and toner particles chargeable by frictional contact with the magnetic carrier particles onto a development sleeve comprised of a non-magnetic sleeve and provided therein, a magnet having alternately and circumferentially arranged magnetic poles of different polarities to thereby form a magnetic brush of the developer, and bringing the surface of a photosensitive drum bearing a latent electrostatic image into frictional contact with the magnetic brush while a bias voltage is applied between the photosensitive drum and the sleeve thereby to form a toner image corresponding to the latent electrostatic image; characterized in that a brush cutting doctor is disposed on the non-magnetic sleeve so that the tip of the doctor is positioned nearly centrally between two magnetic poles of different polarities, and the development is carried out while moving the photo-sensitive drum and the development sleeve in the same direction at the site of frictional contact and the concentration (Ct, %) of the toner in the developer satisfies the following equation <IMAGE> wherein Sc is the specific surface area (cm2/g) of the carrier, St is the specific surface area (cm2/g) of the toner, and k is a number of from 0.80 to 1.14.
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