US4218530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single component magnetic toner
Assignee: Xerox Corp
•
Filing: 1978-07-03
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Granted: 1980-08-19
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Expires: 1998-07-03
Abstract
Abstract A toner and process of its manufacture for use in electrostatic development processes involving a magnetic toner without carrier are disclosed. The toner of the invention is semiconductive and effectively transferred from photoreceptors to plain paper after development. The preferred process of formation involves spray drying from a slurry solution.
Inventors
- 👤 Chin H. Lu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:48
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09733; G03G9/09775; G03G9/0821; G03G9/0823; G03G9/0825; G03G9/083; G03G9/0839; G03G9/0975; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
127 words
A single component, electrically field dependent developer comprising toner particles, said particles comprising a resin and magnetic particles coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material, said magnetic material being present at higher concentration near the toner particle surface than in the interior of particle the toner is characterized by a field dependence such that at low fields of less than 100 volt/cm the resistivity is greater than 10 12 ohm-cm, and less than 10 12 ohm-cm at fields greater than 100 volt-cm, some higher field they exhibit 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 2
Dependent Claim
127 words
A single component, electrically field dependent developer comprising toner particles, said particles comprising a resin and magnetic particles coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material, said magnetic material being present at higher concentration near the toner particle surface than in the interior of particle the toner is characterized by a field dependence such that at low fields of less than 100 volt/cm the resistivity is greater than 10 12 ohm-cm, and less than 10 12 ohm-cm at fields greater than 100 volt-cm, some higher field they exhibit 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 3
Dependent Claim
11 words
The developer of claim 1 wherein said magnetic particles comprises magnetite.
Claim 4
Dependent Claim
25 words
The developer of claim 2 wherein said magnetite is present in an amount of from about 40 to about 70 weight percent of the toner.
Claim 5
Dependent Claim
26 words
The developer of claim 2 wherein said surfactant is present in an amount of between about 1 and about 3 percent by weight of the magnetite.
Claim 6
Dependent Claim
21 words
The developer of claim 1 wherein said toner has a powder resistivity of greater than 10 12 ohm-cm at low fields.
Claim 7
Dependent Claim
21 words
The developer of claim 1 wherein said toner has a powder resistivity of less than 10 8 ohm-cm at high fields.
Claim 8
Dependent Claim
74 words
The developer of claim 1 wherein said surfactant comprises one moiety, displaying affinity to the magnetic particle, consisting of carboxylic groups, sulfate groups, sulfonate groups, phosphate groups, ester groups, alcohol groups, amine groups, amide groups, quanternary ammonium compounds or combinations thereof and a second moiety, displaying affinity to the resin and solvent, consisting of long chain aliphatic groups comprising about 6 to 22 carbon atoms or aromatic groups of about the same carbon content.
Claim 9
Dependent Claim
20 words
The developer of claim 1 wherein said coated magnetic particles comprise magnetite surrounded by a coating of stearic acid derivatives.
Claim 10
Dependent Claim
19 words
The developer of claim 8 wherein said stearic acid derivatives comprise a mixture of fatty acids and calcium salts.
Claim 11
Dependent Claim
23 words
The single component developer of claim 1 wherein the magnetic particles have an average particle size between 0.02 micron and about 1 micron.
Claim 12
Dependent Claim
101 words
A single component electrically field dependent developer comprising toner particles, said particles comprising resin, and a surfactant coated magnetite wherein the surfactant coating comprises a fatty acid or fatty acid derivative and the toner is characterized by a field dependence such that at low fields of less than 100 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 13
Dependent Claim
101 words
A single component electrically field dependent developer comprising toner particles, said particles comprising resin, and a surfactant coated magnetite wherein the surfactant coating comprises a fatty acid or fatty acid derivative and the toner is characterized by a field dependence such that at low fields of less than 100 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 14
Dependent Claim
21 words
The developer of claim 11 wherein the resistivity is less than 10 12 ohm-cm at fields of greater than 100 volt/cm.
Claim 15
Dependent Claim
13 words
The developer of claim 11 wherein the said slope is greater than 10.
Claim 16
Dependent Claim
15 words
The developer of claim 11 wherein said slope is between about 10 and about 20.
Claim 17
Dependent Claim
20 words
The developer of claim 11 wherein the resistivity at fields less than 100 volt/cm is greater than 10 14 ohm-cm.
Claim 18
Dependent Claim
37 words
The developer of claim 11 wherein said fatty acid is selected from the group consisting of stearic acid, palmitic acid, lauric acid, myristic acid, pentadecanic acid, margaric acid, oleic acid, linoleic acid, and mixtures and derivatives thereof.
Claim 19
Dependent Claim
25 words
The developer of claim 11 wherein said magnetite is present in an amount of from about 40 to about 70 weight percent of the toner.
Claim 20
Dependent Claim
26 words
The developer of claim 11 wherein said surfactant coating is present in an amount of about 0.1 to about 10 weight percent of said magnetic material.
Claim 21
Dependent Claim
27 words
The developer of claim 11 wherein said coating surfactant is present in an amount of between about 1 and about 5 percent by weight of the magnetite.
Claim 22
Independent Claim
109 words
A method of imaging comprising forming an electrostatic image, developing said electrostatic image with a single component electrically field dependent developer comprising toner particles said toner particles comprising resin and magnetic pigment, coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material, said developing being conducted at a field strength such that the toner particles have a resistivity of less than 10 12 ohm-cm and electrostatically transferring the thus developed toner image to plain paper at a field strength less than 100 volt/cm at which the toner particles have a resistivity greater than 10 12 ohm-cm.
Claim 23
Independent Claim
109 words
A method of imaging comprising forming an electrostatic image, developing said electrostatic image with a single component electrically field dependent developer comprising toner particles said toner particles comprising resin and magnetic pigment, coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material, said developing being conducted at a field strength such that the toner particles have a resistivity of less than 10 12 ohm-cm and electrostatically transferring the thus developed toner image to plain paper at a field strength less than 100 volt/cm at which the toner particles have a resistivity greater than 10 12 ohm-cm.
Claim 24
Dependent Claim
24 words
The method of claim 20 wherein said magnetic pigment is magnetite coated with a surfactant comprising a fatty acid or a fatty acid derivative.
Claim 25
Dependent Claim
35 words
The method of claim 21 wherein the fatty acid is selected from the group consisting of stearic acid, palmitic acid, myristic acid, pentadecanic acid, margaric acid, oleic acid, linoleic acid, and mixtures and derivatives thereof.
Claim 26
Dependent Claim
17 words
The method of claim 21 wherein said fatty acid material comprises between 6 and 22 carbon atoms.
Claim 27
Dependent Claim
25 words
The method of claim 21 wherein said magnetite is present in an amount of from about 40 to about 70 weight percent of the toner.
Claim 28
Dependent Claim
26 words
The method of claim 21 wherein said surfactant coating is present in an amount of about 0.1 to about 10 weight percent of said magnetic material.
Claim 29
Dependent Claim
27 words
The method of claim 21 wherein said coating surfactant is present in an amount of between about 1 and about 5 percent by weight of the magnetite.
Claim 30
Dependent Claim
27 words
The method of claim 21 wherein the fatty acid material is present in an amount between about 2 and about 3 weight percent of the magnetite particle.
Claim 31
Dependent Claim
20 words
The method of claim 20 wherein the resistivity at fields less than 100 volt/cm is greater than 10 14 ohm-cm.
Claim 32
Dependent Claim
97 words
A single component, electrically field dependent developer comprising toner particles said particles including resin and magnetic pigment coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material said toner exhibiting a substantially constant resistivity greater than 10 12 ohm-cm as the field strength increases to a point where the resistivity decreases at a slope greater than about 5 to a resistivity less than about 10 8 ohm-cm when log of powder resistivity in ohm-cm is plotted against field strength expressed as log E volt/cm.
Claim 33
Dependent Claim
97 words
A single component, electrically field dependent developer comprising toner particles said particles including resin and magnetic pigment coated with a surfactant, the surfactant being present in an amount of about 0.1 to about 10 weight percent of the magnetic material said toner exhibiting a substantially constant resistivity greater than 10 12 ohm-cm as the field strength increases to a point where the resistivity decreases at a slope greater than about 5 to a resistivity less than about 10 8 ohm-cm when log of powder resistivity in ohm-cm is plotted against field strength expressed as log E volt/cm.
References Cited (Backward Citations)
US3928220A
Cited
US3922381A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |