A Color Printer Using LED Array by Electrophotography

Abstract

Using a LED array as an image source, we have constructed a tandem-type electrophotographic color printer composed of4photoconductor drums and4color developers. In this paper, especially, the development of the LED array for color gradation, and the effect due to the tolerance of its light power, mechanical accuracy of dot position, and the thermal effect of LED array are discussed. We also discussed the color registration problems in the tandem-type printer which is easily influenced by the mechanical driving system, the paper transfer system, and the light scan of LED array for 4 photoconductor drums. Furthermore, the pulse control technique of the LED array was developed to obtain the color gradation image, taking the relation between the gradation image and the pulse modulation, the correction for the light power tolerance, and the data transmission speed to the LED into consideration. As a result, the color registration less than 0.1 mm and the gradation image quality more than321evels have been attained.