Abstract: A developer for developing latent electrostatic images for use in the rear side exposure system, composed of an electroconductive magnetic carrier which is composed of electroconductive magnetic carrier particles, each electroconductive magnetic carrier particle including a magnetic base particle and an electroconductive layer formed on the surface of the magnetic base particle, a magnetic high-resistivity magnetic carrier, and an electrically insulating toner; and an image formation method of forming toner images on a photoconductor by using this developer in accordance with the rear side exposure system are disclosed.

Abstract: A particle charging apparatus for charging a photo-sensitive drum by magnetically holding magnetic particles in a charging zone and impressing a charging bias on the magnetic particles. Adjacent to an opposed pole which is disposed on the back side of the photo-sensitive drum on the charging zone upstream side for forming a vertical magnetic field, an opposite polarity magnet or magnetic member is disposed such that a mainly horizontal magnetic field is formed on the drum by the opposed and adjacent poles. A vertical magnetic field is formed on the charging zone downstream side by a main pole and the opposed pole. A non-magnetic sleeve with the main pole therein is rotated in the direction opposite that of the drum, thus causing magnetic particles in the vertical magnetic field to be circulated toward the charging zone upstream side.

Abstract: A developer for developing latent electrostatic images for use in the rear side exposure system, composed of an electroconductive magnetic carrier which is composed of electroconductive magnetic carrier particles, each electroconductive magnetic carrier particle including a magnetic base particle and an electroconductive layer formed on the surface of the magnetic base particle, a magnetic high-resistivity magnetic carrier, and an electrically insulating toner; and an image formation method of forming toner images on a photoconductor by using this developer in accordance with the rear side exposure system are disclosed.

Abstract: An image forming apparatus is disclosed, in which a photo-sensitive member is exposed by exposure means accommodated therein, and development is done substantially simultaneously with the exposure.Three time elements, that is, charging time constant C, i.e., time until reaching of a predetermined charging potential on of the photo-sensitive member in a brushing contact region between the photo-sensitive member and a toner holder after the start of charging, exposure time constant R, i.e., time until the charging potential is attenuated by the exposure to a latent image potential, and development time or time T, during which the photo-sensitive member passes by the brushing contact region, are appropriately determined.