GRADATION RECORDING METHOD

摘要

PURPOSE:To enable gradation recording by bringing the surface charge of an electrostatic latent image to a dot diameter according to a beam length by coulomb repelling force, by controlling the beam length corresponding to a gradation signal by using beam finer than a recorded dot pitch in ion beam for forming the electrostatic latent image. CONSTITUTION:Ion beam 9 generated in a corona ion generator 1 is accelerated by a converging electrode 2 while a beam diameter is throttled and an electric field in a forward direction is applied to a beam length control electrode 3 in a pulse form to control the length of beam passing through said electric field. When ion beam reaches the surface of a dielectric body 7 to which a latent image is formed, each ion expands by coulomb force. Therefore, ion quantity increases as the beam length is extended and the spot diameter thereof becomes large. By utilizing this theory, image density can be expressed by the length of beam.