Invention Grant
US3921571A Multiple development method and apparatus for electrophotographic copiers 失效
电子照相复印机的多重显影方法和装置

  • Patent Title: Multiple development method and apparatus for electrophotographic copiers
  • Patent Title (中): 电子照相复印机的多重显影方法和装置
  • Application No.: US48204074
    Application Date: 1974-06-24
  • Publication No.: US3921571A
    Publication Date: 1975-11-25
  • Inventor: MOORE ROBERT ASULLIVAN DANIEL J
  • Applicant: ITEK CORP
  • Assignee: Itek Corp
  • Current Assignee: Itek Corp
  • Priority: US48204074 1974-06-24
  • Main IPC: G03G15/08
  • IPC: G03G15/08 G03G15/16
Multiple development method and apparatus for electrophotographic copiers
Abstract:
Electrophotographic copying apparatus having a multiple development capability for more completely developing and, hence, improving the quality of images which contain extended solid areas. This multiple development capability is attained by designing the development station in such a manner that the latent electrostatic image to be developed and the developer mixture will move through the development station at a substantially identical velocity as distinguished from conventional systems in which the developer passes through the development station much faster than the image. By matching the velocities of the image and the developer, degradation of the developed, or partially developed, image by the rubbing or sweeping of the carrier beads across the image will be substantially eliminated, and, accordingly, multiple development becomes possible. The substantial matching of velocities is preferably accomplished by significantly reducing the width of the gap between the latent image bearing medium and the development plate through which the developer falls. This increases the density of developer in the gap and the degree of developer agitation and, hence, causes it to fall much slower while still ensuring an adequate supply for effective development of all areas of the image. With a system designed in this way, copies having a quality equal or superior to those obtainable with conventional systems can be achieved with a single development step and at speeds comparable to those available in todays high speed machines. When, however, the image to be developed contains large extended solid areas, any needed number of additional development cycles can be selectively carried out to better develop such images and, hence, provide superior quality copies.
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