Patent US5202213A successfully refreshed from Google Patents.
US5202213A
Expired / Lapsed
US
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Developer with surface treated silicic acid for developing electrostatic image
Assignee: Canon Inc
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Filing: 1992-01-21
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Granted: 1993-04-13
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Expires: 2012-01-21
Abstract
Abstract A developer for developing electrostatic latent images, comprising a mixture of toner and fine powder of silicic acid wherein the mixture has a ratio of B/A of 0.9 or larger provided that the mixture contains A wt. % thereof of the silicic acid fine powder, and contains B wt. % thereof of the silicic acid fine powder after the mixture has been passed through a 200 mesh-sieve.
Inventors
- 👤 Toshiaki Nakahara
- 👤 Hirohide Tanikawa
- 👤 Satoshi Yoshida
- 👤 Masatsugu Fujiwara
- 👤 Kiichiro Sakashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:58
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09708; G03G9/09725
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
68 words
In a developer for developing electrostatic latent images, comprising a mixture of a toner and fine powder of silicic acid; the improvement wherein the fine powder of silicic acid is surface-treated and silicic acid fine powder particles having a size of less than 74 microns are present in amounts of at least 90% based on the total amount of the fine powder of silicic acid in the mixture.
Claim 2
Dependent Claim
68 words
In a developer for developing electrostatic latent images, comprising a mixture of a toner and fine powder of silicic acid; the improvement wherein the fine powder of silicic acid is surface-treated and silicic acid fine powder particles having a size of less than 74 microns are present in amounts of at least 90% based on the total amount of the fine powder of silicic acid in the mixture.
Claim 3
Dependent Claim
93 words
A developer according to claim 1, wherein said toner has a particle size distribution such that it contains 12-60% by number of toner particles having a particle size of 5 microns or smaller, 1-33% by number of toner particles having a particle size of 8-12.7 microns, and 2.0% or less by volume of toner particles having a particle size of 16 microns or larger, and has a volume-average particle size of 4-10 microns, and the fine powder of silicic acid has a BET specific surface area of 30 m 2 /g or larger.
Claim 4
Dependent Claim
24 words
A developer according to claim 2, wherein the fine powder of silicic acid has a BET specific surface area of 50-400 m 2 /g.
Claim 5
Dependent Claim
31 words
A developer according to claim 1, wherein in said mixture the silicic acid fine powder particles having a size less than 74 microns are present in amounts of at least 95%.
Claim 6
Dependent Claim
32 words
A developer according to claim 1, wherein the fine powder of silicic acid has been mixed in an amount of 0.01-8 wt. parts with respect to 100 wt. parts of the toner.
Claim 7
Dependent Claim
32 words
A developer according to claim 1, wherein the fine powder of silicic acid has been mixed in an amount of 0.1-5 wt. parts with respect to 100 wt. parts of the toner.
Claim 8
Dependent Claim
21 words
A developer according to claim 1, wherein said toner comprises a magnetic toner comprising a binder resin and a magnetic material.
Claim 9
Dependent Claim
28 words
A developer according to claim 7, wherein said magnetic toner contains 30-120 wt. parts of the magnetic material with respect to 100 wt. parts of the binder resin.
Claim 10
Dependent Claim
28 words
A developer according to claim 7, wherein said magnetic toner contains 40-110 wt. parts of the magnetic material with respect to 100 wt. parts of the binder resin.
Claim 11
Dependent Claim
23 words
A developer according to claim 1, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a silicone oil.
Claim 12
Dependent Claim
22 words
A developer according to claim 1, wherein the fine powder of silicic acid has a bulk density of 40 g/l or lower.
Claim 13
Dependent Claim
20 words
A developer according to claim 1, wherein the fine powder of silicic acid has a bulk density of 15-30 g/l.
Claim 14
Dependent Claim
44 words
A developer according to claim 1, wherein the fine powder of silicic acid has been prepared by disintegrating fine powder of silicic acid having a bulk density of 50 g/l or higher so as to provide a bulk density of 40 g/l or lower.
Claim 15
Dependent Claim
42 words
A developer according to claim 1, wherein the fine powder of silicic acid has been prepared by disintegrating fine powder of silicic acid having a bulk density of 50 g/l or higher so as to provide a bulk density of 15-30 g/l.
Claim 16
Dependent Claim
101 words
A developer according to claim 1, wherein said toner comprises a positively chargeable magnetic toner and has a particle size distribution such that it contains 12-60% by number of toner particles having a particle size of 5 microns or smaller, 1-33 % by number of toner particles having a particle size of 8-12.7 microns, and 2.0% or less by volume of toner particles having a particle size of 16 microns or larger, and has a volume-average particle size of 4-10 microns; and the fine powder of silicic acid has a BET specific surface area of 30 m 2 /g or larger.
Claim 17
Dependent Claim
31 words
A developer according to claim 15, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a silicone oil having a nitrogen atom in its side chain.
Claim 18
Dependent Claim
22 words
A developer according to claim 16, wherein the fine powder of silicic acid has a bulk density of 40 g/l or lower.
Claim 19
Dependent Claim
20 words
A developer according to claim 16, wherein the fine powder of silicic acid has a bulk density of 15-30 g/l.
Claim 20
Dependent Claim
44 words
A developer according to claim 16, wherein the fine powder of silicic acid has been prepared by disintegrating fine powder of silicic acid having a bulk density of 50 g/l or higher so as to provide a bulk density of 40 g/l or lower.
Claim 21
Dependent Claim
42 words
A developer according to claim 16, wherein the fine powder of silicic acid has been prepared by disintegrating fine powder of silicic acid having a bulk density of 50 g/l or higher so as to provide a bulk density of 15-30 g/l.
Claim 22
Dependent Claim
24 words
A developer according to claim 1, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a silane coupling agent.
Claim 23
Dependent Claim
25 words
A developer according to claim 1, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a nitrogen-containing silane coupling agent.
Claim 24
Dependent Claim
28 words
A developer according to claim 1, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a silicone oil and a silane coupling agent.
Claim 25
Dependent Claim
37 words
A developer according to claim 15, wherein the fine powder of silicic acid comprises silicic acid fine powder surface-treated with a silicone oil having a nitrogen atom in its side chain and a nitrogen-containing silane coupling agent.
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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) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |