A developing device 2 includes a control member 116 for controlling an amount of a developer supplied to an image bearing member 3 by causing a developer captured on a surface of a developing sleeve 119 to be uniform in layer thickness. By controlling a combination of the single, common transfer control line and a transfer control line unique to controlling first transfer transistors in pixels in a row, first and second photodiodes in a pixel can be separately readout. The taps can be weighted to accomplish objectives such as reduction of side lobes in the compressed pulse. The at least one mirror control output includes a value for the drive signal. Independently positionable beam steering elements in a plurality of beam steering elements are operative to receive the beams and direct them to selectable locations on the substrate.