Patent US4949127A successfully refreshed from Google Patents.
US4949127A
Expired / Lapsed
US
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Magnetic brush development process
Assignee: Kyocera Mita Industrial Co Ltd
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Filing: 1989-11-28
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Granted: 1990-08-14
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Expires: 2009-11-28
Abstract
Abstract An optimum image can be obtained by carrying out the development while using a two-component type developer comprising an electroscopic toner and a magnetic carrier and maintaining the peripheral speed ratio of the magnet sleeve to the photosensitive material drum within a certain range according to the average particle size and saturation magnetization of the magnetic carrier and the dynamic friction coefficient of the magnetic brush.
Inventors
- 👤 Tomiyasu Matsuda
- 👤 Teruaki Higashiguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:32
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G13/00; G03G13/06; G03G13/08; G03G13/09; G03G9/0819; G03G9/10; G03G9/107; G03G9/108
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
127 words
A magnetic brush development process in the electrophotography, which comprises supplying a twocomponent type developer comprising an electroscopic toner and a magnetic carrier onto a magnet sleeve to form a magnetic brush and bringing the magnetic brush into sliding contact with the surface of a photosensitive material drum on which an electrostatic latent image is formed, to effect development, wherein the development is carried out under such conditions that the peripheral speed ratio K of the magnet sleeve to the photosensitive material drum satisfies the following requirement: ##EQU3## wherein d represents the average particle size (μm) of the magnetic carrier of the developer, x represents the saturation magnetization (emu/g) of the magnetic carrier of the developer, and μ represents the dynamic friction coefficient of the magnetic brush,
Claim 2
Dependent Claim
127 words
A magnetic brush development process in the electrophotography, which comprises supplying a twocomponent type developer comprising an electroscopic toner and a magnetic carrier onto a magnet sleeve to form a magnetic brush and bringing the magnetic brush into sliding contact with the surface of a photosensitive material drum on which an electrostatic latent image is formed, to effect development, wherein the development is carried out under such conditions that the peripheral speed ratio K of the magnet sleeve to the photosensitive material drum satisfies the following requirement: ##EQU3## wherein d represents the average particle size (μm) of the magnetic carrier of the developer, x represents the saturation magnetization (emu/g) of the magnetic carrier of the developer, and μ represents the dynamic friction coefficient of the magnetic brush,
Claim 3
Dependent Claim
38 words
A development process according to claim 1, wherein the two-component type developer comprises the toner and carrier at such a ratio that the specific surface area ratio of the carrier to the toner is from 1/0.7 to 1/1.3.
Claim 4
Dependent Claim
30 words
A development process according to claim 1, wherein the magnetic carrier has an average particle size of 20 to 200 μm and a saturation magnetization of 30 to 70 emu/g.
Claim 5
Dependent Claim
33 words
A development process according to claim 1, wherein the electroscopic toner is one formed by adding a fine powder of an acrylic polymer and a fine powder of silica to an electroscopic toner.
Claim 6
Dependent Claim
41 words
A development process according to claim 4, wherein the fine powder of the acrylic polymer has a primary particle size of 0.01 to 1 μm and the fine powder of silica has a primary particle size of 0.01 to 1 μm.
Claim 7
Dependent Claim
71 words
A development process according to claim 4, wherein the fine powder of the acrylic polymer is present in an amount of 0.01 to 0.2 part by weight per 100 parts by weight of the electroscopic toner and the fine powder of silica is present in such an amount that the weight ratio of the fine powder of silica to the fine powder of the acrylic polymer is from 1/1 to 1/5.
Claim 8
Dependent Claim
22 words
A development process according to claim 1, wherein the magnetic carrier has an apparent density of 2.4 to 3.0 g/cm 3 .
Claim 9
Dependent Claim
79 words
A development process according to claim 1, wherein the magnetic carrier has such a particle size distribution that the amount of particles having a particle size up to 0.5 time as large as the average particle size is smaller than 0.1% by weight based on the entire carrier and the amount of particles having a particle size 0.7 to 1.4 times as large as the average particle size is at least 90% by weight based on the entire carrier.
Claim 10
Dependent Claim
17 words
A development process according to claim 1, wherein the magnetic carrier is one covered with a resin.
Claim 11
Dependent Claim
30 words
A development process according to claim 9, wherein the covering resin is a composition comprising a melamine resin and a thermoplastic resin containing a hydroxyl group or an alkoxyl group.
Claim 12
Dependent Claim
35 words
A development process according to claim 9, wherein the covering resin is present in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the core of the magnetic carrier.
References Cited (Backward Citations)
US4030447A
Cited
US4309498A
Cited
US4538898A
Cited
US4435494A
Cited
US4540645A
Cited
US4518245A
Cited
US4602863A
Cited
US4637973A
Cited
US4816869A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |