Abstract
Our company achieved high quality and a living long life by the tandem engine color printer which used a-Si photoconductor and LED head. Also, it confirmed relation between the layer composition and the latent image forming of the a-Si photoconductor from the both sides of the simulation and the experiment and it clarified relation between the depth of wear and the latent image forming of the a-SiC : H layer which is the most surface layer of the photoconductor.