CONTACT DEVELOPING METHOD USING INSULATING MAGNETIC ONE-COMPONENT DEVELOPER

摘要

PURPOSE:To obtain vivid images with a magnetic developer in the contact developing method by providing a control electrode member in the gap between a developing roll and a carrying roll and generating an alternating electric field between the control electrode member and the carrying roll and generating a DC electric field between the control electrode member and the developing roll and performing contact development with the magnetic developer. CONSTITUTION:A control electrode 12 is provided in the gap between a developing roll 3 and a carrying roll 4 and is connected to a DC power source 13. An AC bias voltage is applied to the carrying roll 4 by an AC power source 11. A magnetic toner stuck to the roll 4 is carried while controlling its layer thickness by a trimmer 6. The control electrode member 12 consists of plural conductive wires and generates the alternating electric field between the member 12 itself and the carrying roll 4 and prevents this electric field from being transmitted to the developing roll 3. The toner is electrified when passing the member 12 and is stuck uniformly to the developing roll 3. A DC bias higher than the bias voltage applied to the member 12 is applied to the roll 3, and a latent image on a latent image carrier is developed by the contact developing method.