EP0086444A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Magnetic carrier powder for two-component toner
Assignee: TDK Corp
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Filing: 1983-02-08
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Granted: —
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Expires: 2003-02-08
Abstract
Abstract A magnetic carrier powder composed of ferrite powder particles having a spinel structure and an average particle size of less than 30 µm.
Inventors
- 👤 Kenji C/O Tdk Electronics Co. Ltd. Imamura
- 👤 Hiroshi C/O Tdk Electronics Co. Ltd. Saitoh
- 👤 Katsuhisa C/O Tdk Electronics Co. Ltd. Kakizaki
- 👤 Motohiko C/O Tdk Electronics Co. Ltd. Makino
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:00
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/107; G03G9/108; G03G9/1085; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/34; H01F1/36; G03G9/1075
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
24 words
1) A magnetic carrier powder composed of ferrite powder particles having a spinel structure and an average particle size of less than 30 µm.
Claim 2
Dependent Claim
24 words
1) A magnetic carrier powder composed of ferrite powder particles having a spinel structure and an average particle size of less than 30 µm.
Claim 3
Dependent Claim
33 words
2) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles are made of a soft ferrite selected from 2-3 spinel and 1-3 spinel ferrites, a magnetite or a maghemite.
Claim 4
Dependent Claim
66 words
3) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles are made of a spinel ferrite comprising at most 60 molar % of MO where M is Ni, Mn, Mg, Zn, Cu, Co or a combination thereof, as calculated as a divalent metal oxide, and at least 40 molar % of Fe 2 0 3 as calculated as a trivalent metal oxide.
Claim 5
Dependent Claim
19 words
4) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles are made of a magnetite.
Claim 6
Dependent Claim
21 words
5) The magnetic carrier powder according to Claim 3 wherein M is Ni, Mn, Mg, Cu, Zn or a combination thereof.
Claim 7
Dependent Claim
32 words
6) The magnetic carrier powder according to Claim 3 wherein M is a combination of Ni, Mn, Mg, Cu, Zn or a combination thereof, with at most 20 atom % of Co.
Claim 8
Dependent Claim
37 words
7) The magnetic carrier powder according to Claim 3 wherein the spinel ferrite contains at most 5 molar % of an oxide of Ca, Bi , Cr, Ta, Mo, Si, V, B, Pb, K, Na or Ba.
Claim 9
Dependent Claim
24 words
8) The magnetic carrier powder according to Claim 1 wherein the average particle size is within a range of from 2 to 25 µm.
Claim 10
Dependent Claim
41 words
9) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles have a particle size distribution such that at least 70% of the particles have a particle size within a range of +30% of the average particle size.
Claim 11
Dependent Claim
42 words
10) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles have an electric resistance of from 10 4 to 10 1 4 Ω , preferably from 10 5 to 10 12 Ω , when 100 V is applied.
Claim 12
Dependent Claim
25 words
11) The magnetic carrier powder according to Claim 1 wherein the ferrite powder particles have a saturation magnetization σ m of at least 35 emu/g.
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