Patent US3557929A successfully refreshed from Google Patents.
EP0053492A2
Expired / Lapsed
EP
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A composite magnetic developer
Assignee: Kyocera Mita Industrial Co Ltd
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Filing: 1981-11-26
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Granted: —
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Expires: 2001-11-26
Abstract
Abstract A dry composite magnetic developer comprises a dry blend of (A) developer particles comprising a nonpulverizing agglomerate of cubic particles of magnetite having a number average particle size of 1 to 10 microns as measured by an electron microscope dispersed in a binder resin medium and (B) developer particles comprising magnetite particles having a particle size of 0.2 to 1 µm in a binder resin medium at an (A)/ (B) weight ratio of from 95/5 to 10/90.
Inventors
- 👤 Nobushiro Miyakawa
- 👤 Masanori Fujii
- 👤 Kouzi Maekawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 09:44
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
106 words
A dry composite magnetic developer consisting essentially of developer particles of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, characterised in that said developer comprises a dry blend of (A) developer particles comprising a non- pulverizing agglomerate of cubic particles of magnetite having a number average particle size of 1 to 10 microns as measured by an electron microscope dispersed in a binder resin medium and (B) developer particles comprising magnetite particles having a particle size of 0.2 to 1 pm in a binder resin medium at an (A)/(B) weight ratio of from 95/5 to 10/90.
Claim 2
Dependent Claim
106 words
A dry composite magnetic developer consisting essentially of developer particles of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, characterised in that said developer comprises a dry blend of (A) developer particles comprising a non- pulverizing agglomerate of cubic particles of magnetite having a number average particle size of 1 to 10 microns as measured by an electron microscope dispersed in a binder resin medium and (B) developer particles comprising magnetite particles having a particle size of 0.2 to 1 pm in a binder resin medium at an (A)/(B) weight ratio of from 95/5 to 10/90.
Claim 3
Dependent Claim
28 words
A magnetic developer according to claim 1, wherein the agglomerate has an apparent density of 0.5 to 1.5 g/ml as measured according to the method of JIS K-5101.
Claim 4
Dependent Claim
38 words
A magnetic developer according to claim 1 or 2, wherein the agglomerate has a saturation magnetization of 75 to 88 emu/g, a residual magnetization of 3 to 12 emu/g and a coercive force of 40 to 150 Oe.
Claim 5
Dependent Claim
33 words
A magnetic developer according to claim 1, 2 or 3, wherein the agglomerate has substantially the same configuration as that shown in the electron microscope photograph of Fig. 1 of the accompanying drawings.
Claim 6
Dependent Claim
49 words
A magnetic developer according to any one of the preceding claims, wherein the agglomerate in (A) and the fine magnetite in (B) are each present in an amount of 35 to 75% by weight based on the combined weight of the binder resin medium and the powdery magnetic material.
Claim 7
Dependent Claim
40 words
A magnetic developer according to any one of the preceding claims, wherein the developer particles (A) have a number average particle size of 5 to 35 pm, which is at least twice the number average particle size of the agglomerate.
Claim 8
Dependent Claim
30 words
A magnetic developer according to any one of the preceding claims, wherein the developer particles (A) and (B) are present at an (A)/(B) weight ratio of from 95/5 to 30/70.
Claim 9
Dependent Claim
28 words
A magnetic developer according to any one of the preceding claims, wherein the fine magnetite in the developer particles (B) has an apparent density larger than 0.45 g/ml.
Claim 10
Dependent Claim
28 words
A magnetic developer according to any one of the preceding claims, wherein the fine magnetite in the developer particles (B) consists of cubic particles or rounded indeterminate-shape particles.
Claim 11
Dependent Claim
41 words
A magnetic developer according to any one of the preceding claims, wherein the fine magnetite in the developer particles (B) has a shape anisotropy, defined as the ratio of the maximum dimension to the minimum dimension, of from 1.0 to 5.5.
References Cited (Backward Citations)
No citation records indexed.
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