Patent US4192902A successfully refreshed from Google Patents.
US4192902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In situ coating then spray drying of magnetic toner
Assignee: Xerox Corp
•
Filing: 1977-05-02
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Granted: 1980-03-11
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Expires: 1997-05-02
Abstract
Abstract A method of toner formation wherein a dispersion of magnetic pigment, resin, solvent and surfactant is spray dried to form the toner particles. Two preferred processes are disclosed: (1) A dispersion of magnetite, resin, fatty acid, and solvent is prepared by high speed agitation. The dispersion is then spray dried to form toner particles. (2) A dispersion of magnetite, fatty acid and solvent is subject to reflux heating, followed by addition of resin solution prior to spray drying to form toner particles.
Inventors
- 👤 Chin H. Lu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:43
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/0802; G03G9/0815; G03G9/0804; G03G9/0821; G03G9/0823; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
93 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volts/cm and less than 10 12 ohm-cm at fields greater than 100 volts/cm comprising applying a surfactant to magnetic pigment particles, the surfactant being present on the magnetic pigment in an amount of from about 0.1 to 10 percent by weight of the magnetic pigment, spray drying a dispersion of the thus coated magnetic pigment particle in a solution of a resin in a solvent and recovering the toner particles thus formed.
Claim 2
Dependent Claim
93 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volts/cm and less than 10 12 ohm-cm at fields greater than 100 volts/cm comprising applying a surfactant to magnetic pigment particles, the surfactant being present on the magnetic pigment in an amount of from about 0.1 to 10 percent by weight of the magnetic pigment, spray drying a dispersion of the thus coated magnetic pigment particle in a solution of a resin in a solvent and recovering the toner particles thus formed.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein said surfactant is selected from the group comprising fatty acids and fatty acid derivatives.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein said pigment comprises magnetite.
Claim 5
Dependent Claim
21 words
The process of claim 3 wherein said pigment forms between about 30 and about 65 weight percent of said toner particles.
Claim 6
Dependent Claim
22 words
The process of claim 3 wherein said magnetite is present in about 45 to about 55 weight percent of said toner particles.
Claim 7
Dependent Claim
12 words
The process of claim 1 wherein said solvent comprises toluene or chloroform.
Claim 8
Dependent Claim
94 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volt/cm and less than 10 12 ohm-cm at fields greater than 100 volt/cm comprising forming a dispersion of surfactant and magnetic particles in a solvent, heating to reflux, adding a solution of resin and solvent, spray drying and recovering toner particles, the surfactant being present as a coating on the magnetic pigment in the amount of from between about 0.1 and 10 percent by weight based on the weight of the magnetic pigment.
Claim 9
Dependent Claim
94 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volt/cm and less than 10 12 ohm-cm at fields greater than 100 volt/cm comprising forming a dispersion of surfactant and magnetic particles in a solvent, heating to reflux, adding a solution of resin and solvent, spray drying and recovering toner particles, the surfactant being present as a coating on the magnetic pigment in the amount of from between about 0.1 and 10 percent by weight based on the weight of the magnetic pigment.
Claim 10
Dependent Claim
15 words
The process of claim 7 wherein reflux heating is carried out for about 1 hour.
Claim 11
Dependent Claim
19 words
The process of claim 8 wherein said solvent comprises about 60 to about 95 weight percent of the dispersion.
Claim 12
Dependent Claim
20 words
The process of claim 7 wherein said spray drying is carried out at between about 180° F. and 220° F.
Claim 13
Dependent Claim
14 words
The process of claim 7 wherein the dispersion is agitated during the reflux heating.
Claim 14
Dependent Claim
15 words
The process of claim 7 wherein said surfactant comprises fatty acids and fatty acid derivatives.
Claim 15
Dependent Claim
35 words
The process of claim 12 wherein said fatty acids and fatty acid derivatives are selected from the group consisting of lauric, myristic, pentadecanic, palmitic, margaric, stearic, oleic and linolic acids and mixtures and derivatives thereof.
Claim 16
Dependent Claim
11 words
The process of claim 12 wherein said magnetic particles comprise magnetite.
Claim 17
Dependent Claim
12 words
The process of claim 12 wherein said solvent comprises toluene or chloroform.
Claim 18
Dependent Claim
21 words
The method of claim 7 wherein reflux heating is carried out for a time between about 30 minutes and 3 hours.
Claim 19
Dependent Claim
11 words
The process of claim 7 wherein said surfactant comprises stearic acid.
Claim 20
Dependent Claim
21 words
The method of claim 7 wherein said magnetic pigment comprises about 40 to about 65 weight percent of the completed toner.
Claim 21
Dependent Claim
75 words
The method of claim 7 wherein said toner particles recovered possess a field dependence such that at low fields of less than 10 volt/cm the resistivity is greater than 10 12 ohm-cm and at some higher field they exhibit a sharp drop to a resistivity of less than 10 8 ohm-cm along a line of a slope greater than 5 when log of powder resistivity is plotted versus the log of the field in volt/cm.
Claim 22
Dependent Claim
24 words
The method of claim 19 wherein said magnetic pigment is magnetite coated with a surfactant comprising a fatty acid or a fatty acid derivative.
Claim 23
Dependent Claim
13 words
The method of claim 19 wherein the said slope is greater than 10.
Claim 24
Dependent Claim
15 words
The method of claim 19 wherein said slope is between about 10 and about 20.
Claim 25
Dependent Claim
89 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volt/cm and less than 10 12 ohm-cm at fields greater than 100 volt/cm comprising forming a dispersion of magnetic particles, resin and surfactant, subjecting the dispersion to high speed agitation, spray drying and recovering toner particles, the surfactant being present as a coating on the magnetic pigment in the amount of from between about 0.1 and 10 percent by weight based on the weight of the magnetic pigment.
Claim 26
Dependent Claim
89 words
A process of making a field dependent toner having a resistivity greater than 10 12 ohm-cm at fields less than 100 volt/cm and less than 10 12 ohm-cm at fields greater than 100 volt/cm comprising forming a dispersion of magnetic particles, resin and surfactant, subjecting the dispersion to high speed agitation, spray drying and recovering toner particles, the surfactant being present as a coating on the magnetic pigment in the amount of from between about 0.1 and 10 percent by weight based on the weight of the magnetic pigment.
Claim 27
Dependent Claim
21 words
The process of claim 23 wherein said surfactant is selected from the group consisting of fatty acids and fatty acid derivatives.
Claim 28
Dependent Claim
11 words
The method of claim 23 wherein said magnetic pigment comprises magnetite.
Claim 29
Dependent Claim
22 words
The method of claim 23 wherein the magnetic pigment comprises about 40 to about 65 percent by weight of the completed toner.
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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) | 1983-03-11 | 1983-09-10 | 1984-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-11 | 1987-09-10 | 1988-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-11 | 1991-09-10 | 1992-03-11 | $7700.00 | Window Closed / Lapsed |