US5139914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developer for developing electrostatic images and image forming apparatus
Assignee: Canon Inc
•
Filing: 1990-07-26
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Granted: 1992-08-18
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Expires: 2010-07-26
Abstract
Abstract A developer for developing electrostatic latent images is constituted by a toner, and negatively chargeable spherical resin particles having an average particle size of 0.03 - 1.0 micron and a volume resistivity of 10<6> - 10<1><2> ohm.cm. The toner may comprise toner particles and hydrophobic inorganic fine powder, which is generally used in a larger amount than the negatively chargeable spherical resin particles. The negatively chargeable spherical resin particles function to provide a toner image which is faithful to an electrostatic latent image formed on a photosensitive member while preventing toner-sticking onto the photosensitive member preferably in combination with a contact-charging means for charging the photosensitive member.
Inventors
- 👤 Koichi Tomiyama
- 👤 Tsuyoshi Takiguchi
- 👤 Tsutomu Kukimoto
- 👤 Hiroshi Yusa
- 👤 Eiichi Imai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:49
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/0821; G03G9/0823; G03G9/0827
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
42 words
A developer for developing electrostatic latent images comprising: a toner comprising toner particles and hydrophobic inorganic fine powder and negatively chargeable spherical resin particles having an average particle size of 0.03-1.0 micron and a volume resistivity of 10 6 -10 12 ohm.cm.
Claim 2
Dependent Claim
42 words
A developer for developing electrostatic latent images comprising: a toner comprising toner particles and hydrophobic inorganic fine powder and negatively chargeable spherical resin particles having an average particle size of 0.03-1.0 micron and a volume resistivity of 10 6 -10 12 ohm.cm.
Claim 3
Dependent Claim
18 words
The developer according to claim 1, wherein said toner comprises toner particles and hydrophobic metal oxide fine powder.
Claim 4
Dependent Claim
17 words
The developer according to claim 1, wherein said toner comprises toner particles and hydrophobic silica fine powder.
Claim 5
Dependent Claim
24 words
The developer according to claim 1, wherein said toner comprises toner particles and hydrophobic inorganic fine powder treated with silicone oil or silicone varnish.
Claim 6
Dependent Claim
19 words
The developer according to claim 1, wherein said toner comprises toner particles having a volume-particle size of 4-8 microns.
Claim 7
Dependent Claim
13 words
The developer according to claim 1, wherein said toner comprises magnetic toner particles.
Claim 8
Dependent Claim
22 words
The developer according to claim 1, wherein said negatively chargeable spherical resin particles have a triboelectric charge of -50 to -400 μC/g.
Claim 9
Dependent Claim
37 words
The developer according to claim 1, which comprises 0.01-1.0 wt. part of the negatively chargeable spherical resin particles and 0.1-3.0 wt. parts of hydrophobic inorganic fine powder per 100 wt. parts of toner particles constituting the toner.
Claim 10
Dependent Claim
25 words
The developer according to claim 8, wherein said hydrophobic inorganic fine powder is contained in a larger production than the negatively chargeable spherical resin particles.
Claim 11
Dependent Claim
26 words
The developer according to claim 8, wherein 0.2-2.0 wt. parts of the hydrophobic inorganic fine powder is mixed with 100 wt. parts of the toner particles.
Claim 12
Dependent Claim
26 words
The developer according to claim 8, wherein 0.6-1.6 wt. parts of the hydrophobic inorganic fine powder is mixed with 100 wt. parts of the toner particles.
Claim 13
Dependent Claim
23 words
The developer according to claim 1, wherein said toner comprises toner particles, hydrophobic inorganic fine powder and aliphatic acid metal salt fine powder.
Claim 14
Dependent Claim
29 words
The developer according to claim 12, wherein said aliphatic acid metal salt fine powder has a positive chargeability and a primary average particle size of 1 micron or smaller.
Claim 15
Dependent Claim
53 words
The developer according to claim 12, which comprises 0.01-1.0 wt. part of the negatively chargeable spherical resin particles, 0.1-3.0 wt. parts of the inorganic fine powder treated with silicone oil or silicone varnish, and 0.05-0.7 wt. part of the aliphatic acid metal salt fine powder per 100 wt. parts of the toner particles.
Claim 16
Dependent Claim
49 words
The developer according to claim 12, wherein the amount of the hydrophobic inorganic fine powder is larger than the total amount of the negatively chargeable spherical resin particles and the aliphatic acid metal salt and is also larger than 4 times the amount of the aliphatic acid metal salt.
Claim 17
Dependent Claim
52 words
The developer according to claim 1, wherein said toner comprises toner particles containing a binder resin which comprises 3-30 wt. parts of polymerized monomer units having an acid group formed of a carboxyl group or its anhydride per 100 wt. parts of the binder resin and has an acid value of 1-70.
Claim 18
Dependent Claim
13 words
The developer according to claim 16, wherein said toner comprises magnetic toner particles.
Claim 19
Dependent Claim
18 words
The developer according to claim 16, wherein said toner particles have a volume-average particle size of 4-8 microns.
Claim 20
Dependent Claim
114 words
The developer according to claim 17, wherein said magnetic toner particles have a volume-average particle size of 6-8 microns; the developer has a BET specific surface area of 1.8-3.5 m 2 /g, a loose apparent density of 0.4-0.52 g/cm 3 , and a true density of 1.45-1.8 g/cm 3 ; and 100 parts of the magnetic toner particles are mixed with 0.01-1.0 wt. part of the negatively chargeable spherical resin particles having an average particle size of 0.03-1.0 microns, a volume resistivity of 10 6 -10 12 ohm.cm and a triboelectric charge of -50 to -400 μC/g and 0.6-1.6 wt. parts of the hydrophobic inorganic fine powder treated with silicone oil or silicone varnish.
Claim 21
Dependent Claim
25 words
The developer according to claim 19, wherein said hydrophobic inorganic fine powder is contained in a larger production than the negatively chargeable spherical resin particles.
Claim 22
Dependent Claim
22 words
The developer according to claim 1, wherein said negatively chargeable spherical resin particles have a primary average particle size of 0.05-0.8 micron.
Claim 23
Dependent Claim
42 words
The developer according to claim 1, wherein said negatively chargeable spherical resin particles comprise a polymer or copolymer obtained by polymerizing a vinyl monomer selected from the group consisting of styrene, acrylic acid, methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof.
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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) | 1995-08-18 | 1996-02-17 | 1996-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-18 | 2000-02-17 | 2000-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-18 | 2004-02-17 | 2004-08-18 | $7700.00 | Window Closed / Lapsed |