DEVELOPING DEVICE FOR NON-MAGNETIC ONE COMPONENT TYPE DEVELOPER

摘要

PURPOSE:To easily adjust a bristle cutting gap, to make the density of a developer layer on a sleeve uniform and to obtain an excellent image by setting the surface tension of a carrying member within a specified range and forming an electret dielectric layer on a regulating member. CONSTITUTION:The electret layer 40 is provided on a blade 20. Then, the developer 18 is held on the surface of the blade 20 by the electric attraction force of a sleeve 16. When the developer passes between the blade 20 and the sleeve 16, not only the quantity of the developer is physically restricted by the blade 16 but also the developer receives electric repulsive force by the electret having the save polarity as the electrostatically charged polarity of the developer. Therefore, the developer layer is compressed and flocculated by the electric repulsive force of the blade 16. In virtue of the compression and flocculation, allowance is given to the accuracy of the bristle cutting gap, the density of the developer 18 is made uniform and electrostatic charging performance is uniformized. By setting the surface tension of the surface of the developing sleeve 16 at =31dyne/cm, the developer which is not electrostatically charged yet or which is reversely electrostatically charged does not adhere, and only the developer layer which is completely electrostatically charged fully receives the action of the electret and uniformly receives an electric action, so that the density of the developer layer is made uniform and the excellent image is obtained.