PURPOSE: To obtain printing of two colors with a simple apparatus by forming the first and second charge latent images as the charge latent image of a potential larger than a reference voltage with a certain voltage as the reference voltage and the charge latent image of a potential smaller than this and using toners of two colors of charges of mutually different polarities and different colors for these.

CONSTITUTION: The first original picture image is the positive image such as the one where the quantity of light corresponding to the portions where toner is to deposit decreases (or not exposed) and the second original picture image is a negative image. These two images will not mutually overlap at the portions where the toner images are to be formed. The potential of the first image recording part is nearly equal to the initial charge voltage V0. The quantity of light of the background part of the first image is so applied as to become the surface potential of the value Vb about 1/2 the voltage V0. In the exposure of the second image, the quantity of light at which the potential of the image recording part becomes close to the residual potential VR of the photoconductor is applied. In this way, printing of two colors may be accomplished with the simple apparatus.