Abstract: An apparatus for creating multiple color images is disclosed. The apparatus includes a charge retentive surface having a voltage saturation level, a plurality of imaging devices, and a plurality of developing devices. A first imaging device records a latent image on the charge retentive surface at a first exposure level. The latent image is then developed with a layer of toner particles by a first developing device. A second imaging device records a second latent image at a second exposure level. The second exposure level is a function of the voltage saturation level for the charge retentive surface and the maximum mass of the first layer of toner particles. A second developing device develops the second latent image with a second layer of toner particles and a third imaging device records a third latent image at a third exposure level.

Abstract: An apparatus for advancing a copy sheet includes a moving imaging member having an unfused toner image. The copy sheet is in contact with the moving imaging member to transfer the toner image from the imaging member to the copy sheet. The copy sheet is then engaged by a moving sheet transport. A vacuum draws the copy sheet toward the sheet transport while a pressure sensor detects the vacuum pressure in the transport to control the air flow through the transport so as to maintain a low and constant drive force in response to the level of vacuum sensed by the sensor. The low drive force exerted on the sheet is lower than a holding force of the sheet to the moving imaging member thus causing the sheet to slide on the transport.

Abstract: An apparatus for controlling the concentration of toner within a developer material of carrier and toner. The apparatus having a control means for generating a toner addition signal indicative of the amount of toner to be added to the developer material. The control means including the ability to measure the concentration of toner within the developer material during at least a first period and a second period subsequent to the first period. The control means also determining a first concentration error as a function of the deviation between the toner concentration measured during the first period and a reference toner concentration and a second concentration error as a function of the deviation between the toner concentration measured during the second period and the reference toner concentration. Subsequently, the control means generates the toner addition signal as a function of the first and second concentration error values.

Abstract: An apparatus which develops a latent image with marking particles transported from a storage supply into contact therewith. As the marking particles are moved into contact with the latent image, extraneous marking particles are confined and guided gently back to the storage supply thereof. In this way, any clouds of particles formed cannot escape from the development apparatus.

Abstract: An apparatus in which a belt is supported to move in a pre-determined path. A pressurized fluid flows between the belt and at least one support with the side marginal regions being sealed to substantially reduce leakage thereat. This forms a fluid film which at least partially supports the belt and reduces friction between the belt and support.

Abstract: An electrophotographic printing machine in which an arcuate screen member has a plane of curvature substantially normal to the plane of curvature of an arcuate photoconductive member employed therein.