US4485162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic carrier powder having a wide chargeable range of electric resistance useful for magnetic brush development
Assignee: TDK Corp
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Filing: 1983-02-08
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Granted: 1984-11-27
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Expires: 2003-02-08
Abstract
Abstract A magnetic carrier powder composed essentially of particles of a ferrite having a composition represented by the formula (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mg and Co, or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu and Co, and x is greater than 53 molar %.
Inventors
- 👤 Kenji Imamura
- 👤 Hiroshi Saitoh
- 👤 Katsuhisa Kakizaki
- 👤 Motohiko Makino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:26
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/34; H01F1/36; G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/107; G03G9/108; G03G9/1085
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
160 words
A magnetic carrier powder comprising particles of a ferrite having a composition represented by the formula (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mg and Co, or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater than 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibiting a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied, and said ferrite particles are free of a resin coating.
Claim 2
Dependent Claim
160 words
A magnetic carrier powder comprising particles of a ferrite having a composition represented by the formula (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mg and Co, or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater than 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibiting a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied, and said ferrite particles are free of a resin coating.
Claim 3
Dependent Claim
45 words
The magnetic carrier powder according to claim 1 wherein M in the formula I is Mg or a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn and Co.
Claim 4
Dependent Claim
58 words
The magnetic carrier powder according to claim 1 wherein M in the formula I is Mn, Zn or a combination of Mn in an atomic ratio of at least 0.5 with at least one metal selected from the group consisting of Zn, Cu, Mg and Co provided that Mg is in an atomic ratio of less than 0.05.
Claim 5
Dependent Claim
58 words
The magnetic carrier powder according to claim 1 wherein M in the formula I is Ni or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu and Co and x in the formula I is at least 54 molar %.
Claim 6
Dependent Claim
20 words
The magnetic carrier powder according to claim 1 wherein x in the formula I is at most 99 molar %.
Claim 7
Dependent Claim
20 words
The magnetic carrier powder according to claim 1 wherein x in the formula I is at most 90 molar %.
Claim 8
Dependent Claim
61 words
The magnetic carrier powder according to claim 2 wherein MO in the formula I is represented by the formula (MgO).sub.y (XO).sub.1-y (II) where X is Zn or a combination of Zn in an atomic ratio of at least 0.3 with at least one metal selected from the group consisting of Cu, Mn and Co, and y is from 0.05 to 0.99.
Claim 9
Dependent Claim
19 words
The magnetic carrier powder according to claim 7 wherein y in the formula II is from 0.1 to 0.7.
Claim 10
Dependent Claim
61 words
The magnetic carrier powder according to claim 3 wherein MO in the formula I is represented by the formula (MnO).sub.y (YO).sub.1-y (III) where Y is Zn or a combination of Zn in an atomic ratio of at least 0.3 with at least one metal selected from the group consisting of Cu, Mg and Co and y is from 0.05 to 0.99.
Claim 11
Dependent Claim
19 words
The magnetic carrier powder according to claim 9 wherein y in the formula III is from 0.1 to 0.7.
Claim 12
Dependent Claim
62 words
The magnetic carrier powder according to claim 4 wherein MO in the formula I is represented by the formula (NiO).sub.y (ZO).sub.1-y (IV) where Z is Zn or a combination of Zn in an atomic ratio of at least 0.3 with at least one metal selected from the group consisting of Mg, Mn, Cu and Co, and y is from 0.05 to 0.99.
Claim 13
Dependent Claim
19 words
The magnetic carrier powder according to claim 11 wherein y in the formula IV is from 0.1 to 0.7.
Claim 14
Dependent Claim
34 words
The magnetic carrier powder according to claim 1 wherein the ferrite contains at most 5 molar % of an oxide of Ca, Bi, Cr, Ta, Mo, Si, V, B, Pb, K, Na or Ba.
Claim 15
Dependent Claim
22 words
The magnetic carrier powder according to claim 1 wherein the ferrite particles have an average particle size of at most 1000 μm.
Claim 16
Dependent Claim
29 words
The magnetic carrier powder according to claim 1 wherein the ferrite particles have an electric resistance of from 10 5 to 10 12 Ω when 100 V is applied.
Claim 17
Dependent Claim
22 words
The magnetic carrier powder according to claim 1 wherein the ferrite particles have saturation magnetization σ m of at least 35 emu/g.
Claim 18
Dependent Claim
22 words
The magnetic carrier powder according to claim 1 wherein the ferrite particles have saturation magnetization σ m of at least 40 emu/g.
Claim 19
Dependent Claim
196 words
A magnetic carrier powder comprising particles of a ferrite having a composition represented by the formula (I) (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zu, Cu, Mn, and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting Zn, Cu, Mg, and Co, or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater than 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibiting a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied, wherein the resistance of each specific compound within the above formula (I) can be set within the range of 10 4 to 10 14 Ω by variation of the oxidation of the magnetic carrier powder, and said magnetic carrier powder is free of a resin coating.
Claim 20
Dependent Claim
196 words
A magnetic carrier powder comprising particles of a ferrite having a composition represented by the formula (I) (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zu, Cu, Mn, and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting Zn, Cu, Mg, and Co, or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater than 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibiting a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied, wherein the resistance of each specific compound within the above formula (I) can be set within the range of 10 4 to 10 14 Ω by variation of the oxidation of the magnetic carrier powder, and said magnetic carrier powder is free of a resin coating.
Claim 21
Dependent Claim
177 words
In an electrophotography process using magnetic brush development, the improvement wherein a magnetic carrier powder is used in a two component developer wherein said magnetic carrier powder particles are free of resin and comprise a ferrite having a composition represented by the formula (I) (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn, and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mg, and Co or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibitng a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied.
Claim 22
Dependent Claim
177 words
In an electrophotography process using magnetic brush development, the improvement wherein a magnetic carrier powder is used in a two component developer wherein said magnetic carrier powder particles are free of resin and comprise a ferrite having a composition represented by the formula (I) (MO).sub.100-x (Fe.sub.2 O.sub.3).sub.x (I) where M is Mg, Mn, Zn, Ni, a combination of Mg in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mn, and Co, a combination of Mn in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Cu, Mg, and Co or a combination of Ni in an atomic ratio of at least 0.05 with at least one metal selected from the group consisting of Zn, Mg, Mn, Cu, and Co, and x is greater 53 molar %, wherein each magnetic carrier powder composition within the formula is capable of exhibitng a changeable resistance of from 10 4 to 10 14 Ω when 100 V is applied.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |