Electrophotographic image forming

摘要

A photoconductive image forming method in a which charged toner contacts a transparent insulating substrate and is exposed from within the substrate. Exposure reduces the resistivity of the toner so that its charge can be reversed by a bias voltage and the exposed toner will adhere to the image forming substrate simultaneously with exposure and then transfer to a transfer medium. In an alternative embodiment of the invention, a layer of toner is applied to an electroconductive substrate and the toner layer is exposed with a latent image. The charge of the exposed toner is reversed and the exposed toner is removed by an intermediate toner removal device. The remaining toner is then transferred to a transfer medium. Toner suitable for use includes azo-type metal containing black dyes which do not absorb the exposure and can be sensitized to the near infrared region. Multicolor toners, each sensitized to a different exposure wavelength are provided so that a single multiple wavelength exposure and a single development can be used to form multicolor images.