US5204204A
Expired / Lapsed
US
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Carrier for developing electrostatic latent image
Assignee: Powdertech Co Ltd
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Filing: 1991-11-27
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Granted: 1993-04-20
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Expires: 2011-11-27
Abstract
Abstract This invention relates to a carrier for developing electrostatic latent images comprising; carrier core particles having specified physical properties such as mean particle size, a bulk density, ratio of small particles, surface area index and the like, and resin-coating layers formed of specified components at specified content by a sintering process so that the layer resin may have specified physical properties such as ratio of integrated intensity and the like.
Inventors
- 👤 Yuji Shintani
- 👤 Etsuaki Urano
- 👤 Osamu Doi
- 👤 Shinobu Nakasawa
- 👤 Ichiro Demizu
- 👤 Miyoko Ito
- 👤 Kazuhiro Itadaki
- 👤 Nobutaka Torii
- 👤 Yukio Tanigami
- 👤 Toshio Honjo
- 👤 Yuji Sato
- 👤 Toshiyuki Fukumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:21
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1137; G03G9/1131
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
53 words
A carrier for developing electrostatic latent images comprising; carrier core particles having a mean particle size of 40 to 60 μm and a bulk density of 2.45 to 2.65 g/cm 3 , and resin-coating layers the amount of which is 2.7 to 3.5% by weight on the basis of the carrier core particles.
Claim 2
Dependent Claim
53 words
A carrier for developing electrostatic latent images comprising; carrier core particles having a mean particle size of 40 to 60 μm and a bulk density of 2.45 to 2.65 g/cm 3 , and resin-coating layers the amount of which is 2.7 to 3.5% by weight on the basis of the carrier core particles.
Claim 3
Dependent Claim
26 words
A carrier for developing electrostatic latent images as claimed in claim 1, wherein heat decomposition peak temperature of the coating resin is 275° C. or more.
Claim 4
Dependent Claim
28 words
A carrier for developing electrostatic latent images as claimed in claim 1, having a bulk density of 2.35 to 2.55 g/cm 3 after coated with the coating resin.
Claim 5
Dependent Claim
89 words
A carrier for developing electrostatic latent images comprising; carrier core particles composed of a magnetic material; and a resin-coating layer formed by a production method comprising a step of coating the carrier core particles with a solution of thermosetting resin; a step of sintering first the coated particles at a temperature between a thermoset-starting temperature and the thermoset-starting temperature plus 30 ° C.,; and a step of sintering second the first sintered particles at a temperature between the first sintering temperature and the first sintering temperature plus 50° C.
Claim 6
Dependent Claim
89 words
A carrier for developing electrostatic latent images comprising; carrier core particles composed of a magnetic material; and a resin-coating layer formed by a production method comprising a step of coating the carrier core particles with a solution of thermosetting resin; a step of sintering first the coated particles at a temperature between a thermoset-starting temperature and the thermoset-starting temperature plus 30 ° C.,; and a step of sintering second the first sintered particles at a temperature between the first sintering temperature and the first sintering temperature plus 50° C.
Claim 7
Dependent Claim
31 words
A carrier for developing electrostatic latent images as claimed in claim 4, wherein the production method further comprises a pulverizing step between the first sintering step and the second sintering step.
Claim 8
Dependent Claim
31 words
A carrier for developing electrostatic latent images as claimed in claim 4, wherein the thermosetting resin is formed by cross-linking an acrylic polymer or a styrene-acrylic copolymer with a melamine compound.
Claim 9
Dependent Claim
117 words
A carrier for developing electrostatic latent images composed of carrier core particles and a thermosetting resin-coating layer, wherein the number of adsorbed molecules n (molecules/nm 2 ) of carbon dioxide (CO 2 ) per unit area of the carrier expressed by the following formula (I): ##EQU5## wherein (CO 2 ) represents an adsorbed amount of CO 2 in monomolecular layer (ml/g); (A) represents 6×10 23 (molecules/mol)); (N 2 ) represents N 2 specific surface area (cm 2 ), has the relationship represented by the following formula; n.sub.2 /n.sub.1 ≧20 wherein n 1 is the number before the particles are coated with the resin and n 2 is the value after the particles are coated with the resin.
Claim 10
Dependent Claim
117 words
A carrier for developing electrostatic latent images composed of carrier core particles and a thermosetting resin-coating layer, wherein the number of adsorbed molecules n (molecules/nm 2 ) of carbon dioxide (CO 2 ) per unit area of the carrier expressed by the following formula (I): ##EQU5## wherein (CO 2 ) represents an adsorbed amount of CO 2 in monomolecular layer (ml/g); (A) represents 6×10 23 (molecules/mol)); (N 2 ) represents N 2 specific surface area (cm 2 ), has the relationship represented by the following formula; n.sub.2 /n.sub.1 ≧20 wherein n 1 is the number before the particles are coated with the resin and n 2 is the value after the particles are coated with the resin.
Claim 11
Dependent Claim
37 words
A carrier for developing electrostatic latent images as claimed in claim 7, wherein the coating amount of the thermosetting resin is 2.7 to 3.5% by weight on the basis of the weight of the carrier core particles.
Claim 12
Dependent Claim
53 words
A carrier for developing electrostatic latent images as claimed in claim 8, wherein the coating layer is formed by repeating the processes comprising a step of coating the carrier core particles with a solution of a thermosetting resin, a step of sintering the coated particles and a step of pulverizing the sintered particles.
Claim 13
Dependent Claim
35 words
A carrier for developing electrostatic latent images as claimed in claim 9, wherein the coating layer is formed by reducing the amount of the coating resin as the number of times of coating treatment increases.
Claim 14
Dependent Claim
39 words
A carrier for developing electrostatic latent images as claimed in claim 10, wherein the amount of coating resin in the last coating process is one-half or less of the average amount of the coating resin of each coating process.
Claim 15
Dependent Claim
42 words
A carrier for developing electrostatic latent images as claimed in claim 11, wherein the last sintering process is carried out at a temperature between the sintering temperature in each sintering process and the sintering temperature plus 50° C. in each sintering process.
Claim 16
Dependent Claim
154 words
A carrier for developing electrostatic latent images comprising; carrier core particles in which a ratio of small particles of 31 μm or less is 10 volume %, and a mean particle size is 40 to 60 μm and a bulk density is 2.45 to 2.65 g/cm 3 , and a resin layer coating the surface of the core particles at an amount of 2.7 to 3.5% by weight on the basis of the core particles, a ratio of change of large particles having a particle size of 62 μm or more before and after coated with the resin being less than 100% when the ratio is expressed by the following formula (II): (B-A)/A (II) wherein "A" denotes the ratio (%) of the carrier core particles having a particle size of 62 μm or more, and "B" denotes the ratio (%) of the resin-coated carrier particles having a particle size of 62 μm or more.
Claim 17
Dependent Claim
154 words
A carrier for developing electrostatic latent images comprising; carrier core particles in which a ratio of small particles of 31 μm or less is 10 volume %, and a mean particle size is 40 to 60 μm and a bulk density is 2.45 to 2.65 g/cm 3 , and a resin layer coating the surface of the core particles at an amount of 2.7 to 3.5% by weight on the basis of the core particles, a ratio of change of large particles having a particle size of 62 μm or more before and after coated with the resin being less than 100% when the ratio is expressed by the following formula (II): (B-A)/A (II) wherein "A" denotes the ratio (%) of the carrier core particles having a particle size of 62 μm or more, and "B" denotes the ratio (%) of the resin-coated carrier particles having a particle size of 62 μm or more.
Claim 18
Dependent Claim
64 words
A carrier for developing electrostatic latent images comprising; a carrier core particles and a coating layer comprising an acrylic-styrene resin and a melamine resin which is able to cross-link the acrylic-styrene resin to form crosslinkages, the ratio of the integrated intensity between unreacted melamine components and unreacted styrene components of acrylic-styrene resin in the coating layer being in the range of 0.05 to 0.50.
Claim 19
Dependent Claim
64 words
A carrier for developing electrostatic latent images comprising; a carrier core particles and a coating layer comprising an acrylic-styrene resin and a melamine resin which is able to cross-link the acrylic-styrene resin to form crosslinkages, the ratio of the integrated intensity between unreacted melamine components and unreacted styrene components of acrylic-styrene resin in the coating layer being in the range of 0.05 to 0.50.
Claim 20
Dependent Claim
61 words
A carrier for developing electrostatic latent images as claimed in claim 14, wherein the acrylic-styrene resin is composed of at least one kind of acrylic acid, methacrylic acid, acrylic acid esters or methacrylic acid esters having functional groups, the content of acrylic-styrene resin being 5 to 30% by weight, and the content of melamine resin being 10 to 35% by weight.
Claim 21
Dependent Claim
30 words
A carrier for developing electrostatic latent images as claimed in claim 14, wherein the surface area index of the carrier core particles is in the range of 2.2 to 5.2.
Claim 22
Dependent Claim
25 words
A carrier for developing electrostatic latent images as claimed in claim 14, which is used in combination with a toner mainly composed of polyester resins.
Claim 23
Dependent Claim
17 words
A carrier for developing electrostatic latent images as claimed in claim 17, wherein the toner is light-transmittable.
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) | 1996-04-19 | 1996-10-19 | 1997-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-19 | 2000-10-19 | 2001-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-19 | 2004-10-19 | 2005-04-20 | $7700.00 | Window Closed / Lapsed |