Abstract: An apparatus in which a latent image recorded on a photoconductive member is developed with developer material. A developer roller, positioned closely adjacent to the photoconductive member, is arranged to transport the developer material into contact with the photoconductive surface in the development zone. A blade member moves from an operative position to a non-operative position. In the non-operative position, the blade member has the free end portion thereof spaced from the developer roller. This enables the developer roller to transport the developer material into contact with the photoconductive member to develop the latent image recorded thereon. In the operative position, the blade member has the free end portion thereof contacting the developer roller. This prevents the developer roller from transporting the developer material into contact with the photoconductive member to prevent development of the latent image recorded thereon.

Abstract: An apparatus in which particles are moved from one end of a duct to the other end thereof. The particles in the duct are fluidized. A pressure differential is generated which moves the fluidized particles in the duct from one end of the duct to the other end thereof. When the particles pack and cake together, the apparatus automatically moves the toner particles away from the region of the packed and caked toner particles to relieve this condition.

Abstract: An apparatus in which a latent image is developed with marking particles. The marking particles are transported to the latent image. As the marking particles are being moved to the latent image, they are electrically charged by a plate in contact with the transport. The plate, charging the marking particles, is periodically cleaned to remove particles adhering thereto.

Abstract: An apparatus which seals a housing to prevent the escape of toner particles therefrom. The toner particles are captured and softened to become tacky. Additional toner particles stick to the tacky toner particles preventing their escape. Each successive layer of captured toner particles soften and become tacky capturing other toner particles thereto.

Abstract: An apparatus in which a latent image recorded on an image receiving member is developed with marking particles. A developer roller transports the marking particles into the development zone. A blade having at least one aperture therein through which the marking particles pass has the free end portion thereof in contact with the developer roller. In this way, the thickness of the layer of marking particles on the developer roller is controlled.

Abstract: An apparatus in which a latent image recorded on an image receiving member is developed. A metering roller advances marking particles to a developer roller for transportation to the latent image. The thickness of the layer of marking particles on the developer roller is a function of the ratio of the surface speed of the metering roll to developer roll. In this way, a thin layer of marking particles is transported into contact with the latent image to form a powder image on the image receiving member.

Abstract: An apparatus which regulates the developability of a conductive developer mixture by controlling the concentration of toner particles therein. The concentration of toner particles in the developer mixture is adjusted in response to the sensed conductivity.

Abstract: Toner concentration of an electrostatic developer is measured by disposing the developer between two electrodes and agitating the developer to produce electronic noise as a result of triboelectrification and measuring and determining from the generated noise the concentration of the developer.