US4430409A
Expired / Lapsed
US
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Developer for electrophotography with wet process silicic acid
Assignee: Canon Inc
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Filing: 1983-07-29
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Granted: 1984-02-07
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Expires: 2003-07-29
Abstract
Abstract As a developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., there is employed a developer containing a finely divided silicic acid which is a finely divided silicic acid synthesized by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water and the developer can be positively charged strongly and uniformly to visualize the negative electrostatic images, giving a high quality image.
Inventors
- 👤 Toru Matsumoto
- 👤 Masanori Takenouchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:24
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09708; G03G9/09725; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2998
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
44 words
A positively charged developer for electrophotography, comprising a toner particle containing a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 2
Dependent Claim
44 words
A positively charged developer for electrophotography, comprising a toner particle containing a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 3
Dependent Claim
30 words
A developer according to claim 1, wherein the finely divided silicic acid is contained in an amount of 0.01 to 20% by weight based on the weight of the developer.
Claim 4
Dependent Claim
22 words
A developer according to claim 1, wherein the finely divided silicic acid contains 85% by weight or more of SiO 2 .
Claim 5
Dependent Claim
31 words
A developer according to claim 1, wherein the finely divided silicic acid contains sodium in an amount of 0.01 to 10% by weight as calculated in terms of Na 2 O.
Claim 6
Dependent Claim
30 words
A developer according to claim 1, wherein the finely divided silicic acid exhibits a weight loss of 0.1 to 10% by weight when heated at 900° C. for 2 hours.
Claim 7
Dependent Claim
53 words
A positively charged developer comprising mixture of fine toner particles, containing an ethylenic olefin polymer and a finely divided silicic acid synthesized according to a wet process wherein the finely divided silicic acid has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 8
Dependent Claim
53 words
A positively charged developer comprising mixture of fine toner particles, containing an ethylenic olefin polymer and a finely divided silicic acid synthesized according to a wet process wherein the finely divided silicic acid has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 9
Dependent Claim
45 words
A positively charged developer for electrophotography, comprising a toner particles and a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4 percent by weight in distilled water.
Claim 10
Dependent Claim
45 words
A positively charged developer for electrophotography, comprising a toner particles and a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4 percent by weight in distilled water.
Claim 11
Dependent Claim
29 words
A developer according to 7, wherein the finely divided silicic acid is contained in an amount of 0.01 to 20% by weight based on the weight of the developer.
Claim 12
Dependent Claim
29 words
A developer according to 7, wherein the finely divided silicic acid is contained in an amount of 0.01 to 20% by weight based on the weight of the developer.
Claim 13
Dependent Claim
22 words
A developer according to claim 7, wherein the finely divided silicic acid contains 85% by weight or more of SiO 2 .
Claim 14
Dependent Claim
31 words
A developer according to claim 7, wherein the finely divided silicic acid contains sodium in an amount of 0.01 to 10% by weight as calculated in terms of Na 2 O.
Claim 15
Dependent Claim
30 words
A developer according to claim 7, wherein the finely divided silicic acid exhibits a weight loss of 0.1 to 10% by weight when heated to 900° C. for 2 hours.
Claim 16
Dependent Claim
47 words
A positively charged one component magnetic developer for electrophotography, comprising a magnetic toner particle containing a finely divided silicic acid which is prepared by wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 17
Dependent Claim
47 words
A positively charged one component magnetic developer for electrophotography, comprising a magnetic toner particle containing a finely divided silicic acid which is prepared by wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 18
Dependent Claim
30 words
A developer according to claim 12, wherein the finely divided silicic acid is contained in an amount of 0.01 to 20% by weight based on the weight of the developer.
Claim 19
Dependent Claim
22 words
A developer according to claim 12 wherein the finely divided silicic acid contains 85% by weight or more of SiO 2 .
Claim 20
Dependent Claim
31 words
A developer according to claim 12 wherein the finely divided silicic acid contains sodium in an amount of 0.01 to 10% by weight as calculated in terms of Na 2 O.
Claim 21
Dependent Claim
30 words
A developer according to claim 12, wherein the finely divided silicic acid exhibits a weight loss of 0.1 to 10% by weight when heated at 900° C. for 2 hours.
Claim 22
Dependent Claim
48 words
A positively charged two component magnetic developer for electrophotography comprising a magnetic toner particle and a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 23
Dependent Claim
48 words
A positively charged two component magnetic developer for electrophotography comprising a magnetic toner particle and a finely divided silicic acid which is prepared by a wet process and has a pH value of 6 to 11 when suspended at a concentration of 4% by weight in distilled water.
Claim 24
Dependent Claim
30 words
A developer according to claim 17, wherein the finely divided silicic acid is contained in an amount of 0.01 to 20% by weight based on the weight of the developer.
Claim 25
Dependent Claim
22 words
A developer according to claim 17, wherein the finely divided silicic acid contains 85% by weight or more of SiO 2 .
Claim 26
Dependent Claim
31 words
A developer according to claim 17, wherein the finely divided silicic acid contains sodium in an amount of 0.01 to 10% by weight as calculated in terms of Na 2 O.
Claim 27
Dependent Claim
30 words
A developer according to claim 17, wherein the finely divided silicic acid exhibits a weight loss of 0.1 to 10% by weight when heated at 900° C. for 2 hours.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |