US4626489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing toner for development of electrostatic images by stepwise suspension polymerization
Assignee: Canon Inc
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Filing: 1985-04-08
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Granted: 1986-12-02
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Expires: 2005-04-08
Abstract
Abstract A polymerizable mixture containing a monomer, a polymerization initiator and a colorant is subjected to suspension polymerization, and an additional monomer is adsorbed onto the resultant polymer particles and grown by polymerization in the presence of an oil-soluble polymerization initiator to give a toner for development of electrostatic charges excellent in toner characteristics such as triboelectric charging characteristic, storage stability and free flowing property.
Inventors
- 👤 Yoshihiko Hyosu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:48
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/087; G03G9/08784; G03G9/08793; C; C08; C08F; C08F2/00; C08F2/44; C08F257/00; C08F257/02; C08F291/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
120 words
A process for producing a toner for developing electrographic images, comprising: a. dispersing a polymerizable mixture comprising a polymerizable monomer, a polymerization initiator and a colorant in a dispersion in which the polymerizable monomer is substantially insoluble; b. polymerizing the dispersion of the polymerizable mixture in the dispersion medium forming a disperse system having polymeric particles; c. adding an additional polymerizable monomer and an oil-soluble polymerization initiator to adsorb the additional monomer on the polymeric particles; and d. polymerizing the additional monomer to form a polymer, wherein the additional monomer and conditions for step d are selected so that the polymer obtained in said step has a glass transition temperature higher than that of the polymer obtained in step b.
Claim 2
Dependent Claim
120 words
A process for producing a toner for developing electrographic images, comprising: a. dispersing a polymerizable mixture comprising a polymerizable monomer, a polymerization initiator and a colorant in a dispersion in which the polymerizable monomer is substantially insoluble; b. polymerizing the dispersion of the polymerizable mixture in the dispersion medium forming a disperse system having polymeric particles; c. adding an additional polymerizable monomer and an oil-soluble polymerization initiator to adsorb the additional monomer on the polymeric particles; and d. polymerizing the additional monomer to form a polymer, wherein the additional monomer and conditions for step d are selected so that the polymer obtained in said step has a glass transition temperature higher than that of the polymer obtained in step b.
Claim 3
Dependent Claim
35 words
A process according to claim 1, wherein the polymer obtained in the step d has a glass transition temperature higher by 35° C. or more than that of the polymer obtained in the step b.
Claim 4
Dependent Claim
51 words
A process according to claim 1, wherein the additional monomer in the step c is added at a rate equal to or lower than the adsorption rate at which said additional monomer is adsorbed onto the polymer particles, whereby the formation of free liquid droplets of said additional monomer is prevented.
Claim 5
Dependent Claim
12 words
A process according to claim 1, wherein the dispersion medium comprises water.
Claim 6
Dependent Claim
14 words
A process according to claim 4, wherein the dispersion medium further contains a dispersant.
Claim 7
Dependent Claim
20 words
A process according to claim 5, wherein the dispersant comprises a combination of an inorganic dispersing agent and a surfactant.
Claim 8
Dependent Claim
18 words
A process according to claim 1, wherein the polymerizable monomer in the step a contains a crosslinking agent.
Claim 9
Dependent Claim
18 words
A process according to claim 1, wherein the additional monomer in the step c contains a crosslinking agent.
Claim 10
Dependent Claim
14 words
A process according to claim 1, wherein said polymerizable mixture contains a magnetic material.
Claim 11
Dependent Claim
29 words
A process according to claim 1, wherein the polymer particles obtained in the step b has a weight average particle size in the range of from 4 to 27μ.
Claim 12
Dependent Claim
29 words
A process according to claim 1, wherein the polymer particles obtained in the step d has a weight average particle size in the range of from 5 to 30μ.
Claim 13
Dependent Claim
36 words
A process according to claim 1, wherein 5 to 100 parts by weight of the additional monomer are added in the step c per 100 parts by weight of the polymerizable monomer in the step a.
References Cited (Backward Citations)
US4415644A
Cited
US4448871A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-01 | 1990-06-02 | 1990-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-01 | 1994-06-02 | 1994-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-01 | 1998-06-02 | 1998-12-02 | $7700.00 | Window Closed / Lapsed |