Improved method and apparatus for forming an electrostatic latent image on a recording medium by the simultaneous projection of an ion current and exposure to image light, in which a control grid for controlling the ion current has a plurality of layers, including a photoconductive layer, a conductive layer, and an insulating layer. A first bias voltage is applied to the conductive layer to form an electric field which directs the ion current toward the recording medium, and a second bias voltage, higher than the first bias voltage, forms a second electric field in the control grid for controlling passage of the ions. The recording medium is adapted to absorb the image light thereon.