(19)
(11) EP 0 482 867 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
19.11.1992 Bulletin 1992/47

(43) Date of publication A2:
29.04.1992 Bulletin 1992/18

(21) Application number: 91309719.2

(22) Date of filing: 21.10.1991
(51) International Patent Classification (IPC)5: G03G 15/08
(84) Designated Contracting States:
DE FR GB

(30) Priority: 22.10.1990 US 601088

(71) Applicant: XEROX CORPORATION
Rochester New York 14644 (US)

(72) Inventors:
  • Thompson, Michael D.
    Rochester, New York 14620 (US)
  • Wayman, William H.
    Ontario, New York 14519 (US)

(74) Representative: Reynolds, Julian David et al
Rank Xerox Ltd Patent Department Parkway
Marlow Buckinghamshire SL7 1YL
Marlow Buckinghamshire SL7 1YL (GB)


(56) References cited: : 
   
       


    (54) Development apparatus


    (57) An apparatus in which a latent image is developed with marking particles. The marking particles (50) are transported to the latent image by a donor roller (30). As the marking particles are being moved to the latent image, they are electrically charged by a blade (36) in contact with the donor roller. An AC potential is applied on the blade. The AC potential is operator adjustable to change the charge on the toner particles. This corrects for changes in the environment and permits the slope of the tone reproduction curve to be optimized for the latent image being developed.






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