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US4686935A Expired / Lapsed US ⏱️ 0.0 years remaining

Developing device

Assignee: Kyocera Mita Industrial Co Ltd
•
Filing: 1985-07-30
•
Granted: 1987-08-18
•
Expires: 2005-07-30
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Abstract

Abstract Disclosed is a development device comprising a development sleeve of a non-magnetic material, a magnet having a plurality of magnetic poles and fixed within the sleeve, a mechanism for rotating the sleeve, a mechanism for agitating a developer composed of a magnetic carrier and a chargeable toner and supplying it to the sleeve, a mechanism for adjusting a magnetic brush formed on the sleeve to a predetermined brush length and supplying it to a development zone, and a mechanism for scraping off the magnetic brush which has gone past the development zone from the sleeve, said magnetic poles consisting of a main pole for development corresponding to the development zone and poles for conveying corresponding to a conveying zone ranging from the position of supplying the developer to the position of cutting the magnetic brush, said magnetic carrier being a ferrite carrier, and each said conveying magnetic pole having a magnetic flux density 50 to 86% of that of the main pole for development.

Inventors

  • 👤 Toshikazu Matsui
  • 👤 Akira Fushida
  • 👤 Nobuyasu Honda
  • 👤 Minoru Nakao
  • 👤 Nobuyuki Tsuji

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 15:05
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0921; G03G13/00; G03G13/06; G03G13/08; G03G13/09

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 178 words
In a development device comprising a development sleeve of a non-magnetic material, a magnet having a plurality of magnetic poles and fixed within the sleeve, a mechanism for rotating the sleeve, a mechanism for agitating a developer composed of a magnetic carrier and a chargeable toner and supplying it to the sleeve, a mechanism for adjusting a magnetic brush formed on the sleeve to a predetermined brush length and supplying it to a development zone, and a mechanism for scraping off the magnetic brush which has gone past the development zone from the sleeve, said magnetic poles consisting of a main pole for development corresponding to the development zone and poles for conveying corresponding to a conveying zone ranging from the position of supplying the developer to the position of cutting the magnetic brush, the improvement wherein said magnetic brush is composed of said magnetic carrier, which is a ferrite carrier and said chargeable toner, and each said magnetic pole for conveying has a magnetic flux density 55 to 80% of that of the main pole for development.
Claim 2
Dependent Claim 178 words
In a development device comprising a development sleeve of a non-magnetic material, a magnet having a plurality of magnetic poles and fixed within the sleeve, a mechanism for rotating the sleeve, a mechanism for agitating a developer composed of a magnetic carrier and a chargeable toner and supplying it to the sleeve, a mechanism for adjusting a magnetic brush formed on the sleeve to a predetermined brush length and supplying it to a development zone, and a mechanism for scraping off the magnetic brush which has gone past the development zone from the sleeve, said magnetic poles consisting of a main pole for development corresponding to the development zone and poles for conveying corresponding to a conveying zone ranging from the position of supplying the developer to the position of cutting the magnetic brush, the improvement wherein said magnetic brush is composed of said magnetic carrier, which is a ferrite carrier and said chargeable toner, and each said magnetic pole for conveying has a magnetic flux density 55 to 80% of that of the main pole for development.
Claim 3
Dependent Claim 21 words
The development device of claim 1 wherein the torque required for the rotation of sleeve is not more than 8.5 kg-cm.
Claim 4
Dependent Claim 25 words
The development device of claim 1 wherein the main pole for development has a magnetic flux density in the range of 700 to 1,000 gauss.
Claim 5
Dependent Claim 19 words
The development device of claim 1 wherein the ferrite carrier is in the form of spherical sintered ferrite particles.
Claim 6
Dependent Claim 26 words
The development device of claim 4 wherein the ferrite carrier particles have an average particle diameter of 30 to 100 microns, particularly 35 to 45 microns.
Claim 7
Dependent Claim 15 words
The development device of claim 4 wherein the ferrite carrier particles are Cu/Zn/Mn-type ferrite particles.

References Cited (Backward Citations)

US4555172A Cited
US4451134A Cited
US4557992A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-08-17 1991-02-16 1991-08-18 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-08-17 1995-02-16 1995-08-18 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-08-17 1999-02-16 1999-08-18 $7700.00 Window Closed / Lapsed

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