Abstract: This invention discloses a developing apparatus wherein a brush of a developing agent is formed on a developing sleeve by a magnetic field of a permanent magnet disposed inside the developing sleeve, and at least the developing sleeve is rotated while the brush is kept in contact with a photosensitive body, thereby developing an electrostatic latent image formed on the photosensitive body. In this apparatus, an agitating member having magnetic ring portions which abut against the developing sleeve and an agitating portion for agitating the developing agent is pivotally disposed in a developing vessel to be parallel to the developing sleeve, and a rotation detecting unit for outputting a signal corresponding to a rotational speed of the agitating member and a residual amount detecting unit for detecting a residual amount of the developing agent in the developing vessel in accordance with an output from the rotation detecting unit are provided.

Abstract: The development apparatus of a developer impingement type comprises a developer distributor having a developer impingement outlet for injecting a liquid developer against the surface of a photoconductor member having a latent electrostatic image thereon, and a developer inlet for introducing the liquid developer into the developer distributor, and a coil shaped buffer member disposed between the developer injection outlet and the developer inlet, extending along the developer impingement outlet which covers an image area of the photoconductor member with a predetermined space from the surface of the photoconductor member.