(19)
(11) EP 0 405 694 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
05.06.1991 Bulletin 1991/23

(43) Date of publication A2:
02.01.1991 Bulletin 1991/01

(21) Application number: 90201738.3

(22) Date of filing: 29.06.1990
(51) International Patent Classification (IPC)5: G03G 13/09
(84) Designated Contracting States:
DE FR GB NL

(30) Priority: 30.06.1989 JP 166952/89

(71) Applicant: MITA INDUSTRIAL CO., LTD.
Osaka 540 (JP)

(72) Inventor:
  • Matsuda, Tomiyasu
    Yokosuka-shi, Kanagawa-ken (JP)

(74) Representative: Smulders, Theodorus A.H.J., Ir. et al
Vereenigde Octrooibureaux Nieuwe Parklaan 97
2587 BN 's-Gravenhage
2587 BN 's-Gravenhage (NL)


(56) References cited: : 
   
       


    (54) Developing method using two-component type developer


    (57) In a developing method comprising delivering a two-component type developer (18) comprising a magnetic carrier and a toner and developing an electrostatic latent image on a photosensitive drum (15), the developing conditions are set so that the degree (R) of substitution of the developer, which is the ratio of substitution of the volume of the developing zone by a fresh carrier/toner aggregate (developer) during the developing time, is within a specific range of from 16.00 to 33.00%. According to this developing method, in the reproduction of multiple fine lines, the line width is kept constant in each line and front end lacking or rear end lacking can be prevented, and an image having a high density and a high quality can be formed with an excellent image reproducibility.







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