Patent US3305580A successfully refreshed from Google Patents.
Patent CA1103079A successfully refreshed from Google Patents.
CA1103079A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Semi-conductive steel carrier particles
Assignee: Xerox Corp
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Filing: 1977-02-23
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Granted: 1981-06-16
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Expires: 1997-02-23
Abstract
Abstract SEMI-CONDUCTIVE STEEL CARRIER PARTICLES ABSTRACT OF THE DISCLOSURE Magnetically-responsive electrostatographic carrier particles having semi-conductive properties are prepared by firing steel shot particles in an oxygen deficient atmosphere as to provide the carrier particles with an oxide coating. More particularly, commercially available steel shot is placed in a furnace wherein the atmosphere has an oxygen content of less than about 18 percent oxygen and the steel shot is fired at a temperature of between about 900°F and about 1600°F for a period of time of between about 10 minutes and up to about 2 hours. When employed with finely-divided toner particles to develop electrostatic latent images in a magnetic-brush development apparatus, the carriers have been found to provide developed images having lower background densities and higher resolution than prior known carrier materials.
Inventors
- 👤 Louis H. Burrows, Jr.
- 👤 John A. Creatura
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-07 11:53
CPC Classifications
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Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
92 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particle having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 2
Dependent Claim
92 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particle having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 3
Dependent Claim
53 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle in accordance with claim 1 wherein said atmosphere has an oxygen content of between about 1 percent and about 12 percent by weight and said particles are fired at a temperature of between about 900°F and about 1500°F for between about 30 minutes and about 60 minutes.
Claim 4
Dependent Claim
53 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle in accordance with claim 1 wherein said atmosphere has an oxygen content of between about 4 percent and about 10 percent by weight and said particles are fired at a tempera-ture of between about 965°F and about 1470°F for between about 30 minutes and about 60 minutes.
Claim 5
Dependent Claim
27 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle in accordance with claim 1 wherein said oxide coating comprises from between about 0.25 micron to about 1 micron in thickness.
Claim 6
Dependent Claim
26 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle in accordance with claim 1 wherein said metallic particles are selected from the group consisting of ferromagnetic and iron alloys.
Claim 7
Dependent Claim
27 words
A magnetically-responsive, semi-conductive electrostatographic carrier particle in accordance with claim 1 wherein said carrier particle has a volume resistivity of between about 105 ohm-cm and 1012 ohm-cm.
Claim 8
Dependent Claim
111 words
An electrostatographic developer mixture comprising finely-divided toner particles electro-statically clinging to the surface of a carrier, said carrier comprising magnetically-responsive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particles having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 9
Dependent Claim
111 words
An electrostatographic developer mixture comprising finely-divided toner particles electro-statically clinging to the surface of a carrier, said carrier comprising magnetically-responsive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particles having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 10
Dependent Claim
169 words
An electrostatographic imaging process comprising the steps of providing an electrostato-graphic imaging member having a recording surface, forming an electrostatic latent image on said recording surface, and contacting said electrostatic latent image with a developer mixture comprising finely-divided toner particles electrostatically clinging to the surface of a carrier, said carrier comprising magne-tically-responsive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particles having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns, whereby at least a portion of said finely-divided toner particles are attracted to and deposited on said recording surface in conformance with said electrostatic latent image.
Claim 11
Dependent Claim
169 words
An electrostatographic imaging process comprising the steps of providing an electrostato-graphic imaging member having a recording surface, forming an electrostatic latent image on said recording surface, and contacting said electrostatic latent image with a developer mixture comprising finely-divided toner particles electrostatically clinging to the surface of a carrier, said carrier comprising magne-tically-responsive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said carrier particles having been prepared by firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns, whereby at least a portion of said finely-divided toner particles are attracted to and deposited on said recording surface in conformance with said electrostatic latent image.
Claim 12
Dependent Claim
92 words
A process for preparing magnetically-respon-sive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said process comprising firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 13
Dependent Claim
92 words
A process for preparing magnetically-respon-sive, semi-conductive electrostatographic carrier particles having an average particle diameter of from between about 30 microns and about 1,000 microns, said process comprising firing metallic, magnetic particles in an atmosphere having an oxygen content of between about 1 percent and about 18 percent by weight at a temperature of between about 900°F and about 1600°F for between about 10 minutes and up to about 2 hours whereby said carrier particles are provided with an oxide coating having a thickness of between about 0.25 micron and about 5 microns.
Claim 14
Dependent Claim
56 words
A process for preparing magnetically-responsive, semi-conductive electrostatographic carrier particles in accordance with claim 9 wherein said atmosphere has an oxygen content of between about 1 percent and about 12 percent by weight and said particles are fired at a temperature of between about 900°F and about 1500°F for between about 30 minutes and about 60 minutes.
Claim 15
Dependent Claim
56 words
A process for preparing magnetically-responsive, semi-conductive electrostatographic carrier particles in accordance with claim 9 wherein said atmosphere has an oxygen content of between about 4 percent and about 10 percent by weight and said particles are fired at a temperature of between about 965°F and about 1470°F for between about 30 minutes and about 60 minutes.
Claim 16
Dependent Claim
36 words
A process for preparing magnetically-responsive, semi-conductive electrostatographic carrier particles in accordance with claim 9 wherein said metallic particles are selected from the group consisting of ferromagnetic materials such as steel and iron alloys in various forms.
References Cited (Backward Citations)
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