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EP0091654A2
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EP
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Electrophotographic ferrite carrier
Assignee: Proterial Ltd
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Filing: 1983-04-06
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Granted: —
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Expires: 2003-04-06
Abstract
Abstract An electrophotographic ferrite carrier with substantially spherical shape based on a magnetoplumbite structure of hexagonal ferrite or ferroxplana structure derived from the magnetoplumbite structure has a high electrical resistivity and a longer life.
Inventors
- 👤 Tsutomu Iimura
- 👤 Minoru Chinju
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 12:28
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; G03G9/1075; G03G9/108; G03G9/1085
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
An electrophotographic ferrite carrier with substantially spherical shape, which comprises a magnetoplumbite structure of hexagonal ferrite represented by the general formula MeFe 12 O 19 , wherein Me is Ba, Sr, Pb or Ca and a portion of Me is substituted with at least one of monovalent, divalent and higher valence metals, or a ferroxplana structure derived from said MeFe 12 O 19 hexagonal ferrite, Z type (Ba 3 Me' 2 Fe 24 O 41 )' Y type (Ba 2 Me'Fe 12 O 22 ), W type (BaMe' 2 Fe 16 O 27 ), or X type (Ba 2 Me' 2 Fe 28 O 46 ), where at least of Ba and Me are substituted with at least one substituent of monovalent, divalent and higher valence metals represented by Me', and having an electrical resistivity of at least 10 3 Ω.cm, a saturation-magnetization of at least 10 emu/g and an average particle size of 20 - 1,OOO µm.
Claim 2
Dependent Claim
158 words
An electrophotographic ferrite carrier with substantially spherical shape, which comprises a magnetoplumbite structure of hexagonal ferrite represented by the general formula MeFe 12 O 19 , wherein Me is Ba, Sr, Pb or Ca and a portion of Me is substituted with at least one of monovalent, divalent and higher valence metals, or a ferroxplana structure derived from said MeFe 12 O 19 hexagonal ferrite, Z type (Ba 3 Me' 2 Fe 24 O 41 )' Y type (Ba 2 Me'Fe 12 O 22 ), W type (BaMe' 2 Fe 16 O 27 ), or X type (Ba 2 Me' 2 Fe 28 O 46 ), where at least of Ba and Me are substituted with at least one substituent of monovalent, divalent and higher valence metals represented by Me', and having an electrical resistivity of at least 10 3 Ω.cm, a saturation-magnetization of at least 10 emu/g and an average particle size of 20 - 1,OOO µm.
Claim 3
Dependent Claim
66 words
The electrophotographic ferrite carrier according to Claim 1, wherein MeO as BaO, SrO, PbO or CaO is in an amount of 5 - 30% by mole, Me'O comprising at least one substituent of the.monovalent, divalent and higher valence metals as Me' is in an amount of 5 - 40% by mole, and Fe 2 0 3 is in an amount of 50 - 90% by mole.
Claim 4
Dependent Claim
23 words
The electrophotographic ferrite carrier according to Claim 1 or 2, wherein the carrier has a coercisve force of not more than 8000 A/r.
Claim 5
Dependent Claim
23 words
The electrophotographic ferrite carrier according to Claim 1, 2 or 3, wherein the ferrite carrier has a permeability p of at least 10.
Claim 6
Dependent Claim
25 words
The electrophotographic ferrite carrier according to Claim 1, 2, 3 or 4, wherein the ferrite carrier has a Curie temperature Tc of at least 50°C.
Claim 7
Dependent Claim
29 words
The electrophotographic ferrite carrier according to Claim 1, 2, 3, 4, or 5, wherein particles of the ferrite carrier has a strength of at least 1,000 g/cm 2 .
Claim 8
Dependent Claim
25 words
The electrophotographic ferrite carrier according to Claim 1, 2, 3, 4, 5 or 6, wherein particle surfaces of the ferrite carrier are oxidized or reduced.
Claim 9
Dependent Claim
25 words
The electrophotographic ferrite carriers according to Claim 1, 2, 3, 4, 5, or 6, wherein particle surfaces of the ferrite carrier are coated with resin.
References Cited (Backward Citations)
No citation records indexed.
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