| 摘要 |
PURPOSE:To stabilize formation of a high resolution image by disposing an electrode, applied with a surface layer composed of a material having volume resistivity variable with the intensity of working electric field, oppositely to a recording electrode. CONSTITUTION:A tubular electrode 5 has a double layer structure in which a surface layer 5b is laminated on the peripheral surface of a conductive sleeve 5a. The surface layer 5b is composed of such material as the volume resistivity decreases as the intensity of working electric field increases. Developing field for forming black dots has maximum intensity in the center of the width of recording electrode line and the intensity decreases substantially in symmetrical toward the opposite ends over the width of the electrode. Since the surface layer 5b composed of an dielectric is applied on the tubular electrode 5 at a recording position W, volume resistivity is minimized at a part opposing to the lateral center of the recording electrode line when the developing electric field functions on the surface layer 5b of the tubular electrode and the electric lines of force is converged to the central part of dot thus reducing the radiation angle theta. According to the constitution, a recording image having high resolution can be formed stably for a long term. |
