Abstract: A toner maintenance system for an electrophotographic developer unit, including a sump for storing a quantity of developer material comprised of toner material; a first member for transporting developer material from the sump, a viewing window, in communication with toner material, in the sump; an optical sensor, for measuring reflected light off the viewing window and toner material, and generating a signal indicative thereof. A toner concentration controller is adapted to receive a signal from the optical sensor and to generate an “Add Toner” signal to replenish toner material in the sump.

Abstract: A toner maintenance system for an electrophotographic developer unit, including a sump for storing a quantity of developer material a sump for storing a quantity of developer material comprised of toner material; a first member for transporting a mixture of developer material and toner particles from the sump, a viewing window, in communication with toner material, in the sump; an optical sensor, device for measuring reflected light off the viewing window and toner material, and generating a signal indicative thereof. A toner concentration controller is adapted to receive a signal from the sensor and to generate an “Add Toner” signal to replenish toner in the sump.

Abstract: There is provided a method for use with a printing machine having a movable imaging member and a projecting system for modulating a beam and projecting an image into the movable imaging member. The printing machine further includes a developer for application of developer material to the image projected onto the movable imaging member for transfer of the image to a print media sheet.

Abstract: An image development system for developing a latent image on an imaging surface, such as a xerographic photoreceptor, with plural development rollers having internal axially extending developer magnets with relatively offset axial end positions, and wherein at least one development roller has a smooth surface area at that same end, to reduce edge banding image defects from the interaction of the axial ends of the magnets of adjacent development rollers, especially for large size copy sheets being printed, such as B4 size. The image developer unit may have three development rollers with three different lengths of developer magnets to provide three different magnetic end positions staggered on opposite sides of the end position of the large sheet (relative to the imaging surface).