US4315064A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic photographic copying process
Assignee: Kyocera Mita Industrial Co Ltd
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Filing: 1979-11-28
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Granted: 1982-02-09
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Expires: 1999-11-28
Abstract
Abstract Disclosed is an electrostatic photographic copying process comprising causing a substrate carrying an electrostatic latent image thereon to fall in contact with a magnetic brush of a one-component type magnetic developer to effect development of the electrostatic latent image and electrostatically transferring the formed image of the developer onto a transfer sheet, wherein a magnetic developer having an electrostatic capacity of 7.8 to 9.8 PF (picofarad) as determined under conditions of an electrode spacing of 0.65 mm, an electrode sectional area of 1.43 cm 2 and an electrode load of 105 cm 2 and a dielectric constant of 4 to 5 as determined under the above conditions is used as the one-component type magnetic developer.
Inventors
- 👤 Nobuhiro Miyakawa
- 👤 Takashi Teshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:06
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/0821; G03G9/0823; G03G9/083; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
227 words
An electrostatic photographic copying process comprising causing a substrate carrying an electrostatic latent image thereon to fall in contact with a magnetic brush of a one-component type magnetic developer to effect development of the electrostatic latent image and electrostatically transferring the formed image of the developer onto a transfer sheet, wherein the magnetic developer comprises a resin medium and a finely divided magnetic material dispersed therein, the resin medium comprising a copolymer comprising (a) at least one aromatic vinyl monomer and (b) at least one mono- or di-ethylenically unsaturated monomer other than the aromatic vinyl monomer, the amount of the finely divided magnetic material being 45 to 65% by weight based on the total developer, the amount of said copolymer being 30 to 120% by weight based on the finely divided magnetic material, said magnetic developer being prepared by melt-kneading the mixture of the resin medium and the finely divided magnetic material and cooling the kneaded composition and pulverizing the cooled composition, said magnetic developer having an electrostatic capacity of 7.8 to 9.32 PF (picofarad) as determined under conditions of an electrode spacing of 0.65 mm, an electrode sectional area of 1.43 cm 2 and an electrode load of 105 cm 2 , and a dielectric constant of 4 to 4.78 and a volume resistivity of at least 5×10 13 Ω-cm, as determined under the above conditions.
Claim 2
Dependent Claim
227 words
An electrostatic photographic copying process comprising causing a substrate carrying an electrostatic latent image thereon to fall in contact with a magnetic brush of a one-component type magnetic developer to effect development of the electrostatic latent image and electrostatically transferring the formed image of the developer onto a transfer sheet, wherein the magnetic developer comprises a resin medium and a finely divided magnetic material dispersed therein, the resin medium comprising a copolymer comprising (a) at least one aromatic vinyl monomer and (b) at least one mono- or di-ethylenically unsaturated monomer other than the aromatic vinyl monomer, the amount of the finely divided magnetic material being 45 to 65% by weight based on the total developer, the amount of said copolymer being 30 to 120% by weight based on the finely divided magnetic material, said magnetic developer being prepared by melt-kneading the mixture of the resin medium and the finely divided magnetic material and cooling the kneaded composition and pulverizing the cooled composition, said magnetic developer having an electrostatic capacity of 7.8 to 9.32 PF (picofarad) as determined under conditions of an electrode spacing of 0.65 mm, an electrode sectional area of 1.43 cm 2 and an electrode load of 105 cm 2 , and a dielectric constant of 4 to 4.78 and a volume resistivity of at least 5×10 13 Ω-cm, as determined under the above conditions.
Claim 3
Dependent Claim
26 words
An electrostatic photographic copying process according to claim 1 wherein the content of the aromatic vinyl monomer in said copolymer is 20 to 95% by weight.
Claim 4
Dependent Claim
29 words
An electrostatic photographic copying process according to claim 1 wherein the amount of said copolymer is from 40 to 100% by weight based on the finely divided magnetic material.
Claim 5
Dependent Claim
33 words
An electrostatic photographic copying process according to claim 1 wherein the amount of the finely divided magnetic material is in the range of 50 to 60% by weight, based on the total developer.
Claim 6
Dependent Claim
55 words
An electrostatic photographic copying process according to claim 1 wherein the finely divided magnetic material has a particle size distribution such that particles having a size larger than 0.5 micron occupy less than 20% of the total particles and particles having a size smaller than 0.3 micron occupy less than 20% of the total particles.
Claim 7
Dependent Claim
47 words
An electrostatic photographic copying process according to claim 1 wherein the fine particles of the magnetic material are coated with fatty acid, a resin or a metal salt thereof or a surface-active agent in an amount of 0.1 to 30% by weight, based on the magnetic material.
Claim 8
Dependent Claim
26 words
An electrostatic photographic copying process according to claim 1 wherein the size of the magnetic developer particles is in the range of 5 to 35 microns.
Claim 9
Dependent Claim
158 words
An electrostatic photographic copying process according to claim 6 wherein said resin medium comprises a copolymer comprising (a) at least one aromatic vinyl monomer selected from compounds represented by the following formula (I): ##STR4## wherein R 1 stands for a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or a halogen atom, R 2 stands for a lower alkyl group or a halogen atom, and n is an integer of up to 2, or vinylnaphthalene; and (b) at least one mono- or di-ethylenically unsaturated monomer selected from acrylic monomers represented by the following formula (II): ##STR5## wherein R 3 stands for a hydrogen atom or a lower alkyl group, and R 4 stands for a hydroxyl group, an alkoxy group, a hydroxyalkoxy group or an aminoalkoxy group, or conjugated diolefin monomers represented by the following formula (III): ##STR6## wherein R 5 stands for a hydrogen atom, a lower alkyl group or a chlorine atom.
Claim 10
Dependent Claim
31 words
An electrostatic photographic copying process according to claim 8 wherein said resin medium is a copolymer of an aromatic vinyl monomer of formula (I) and an acrylic monomer of formula (II).
Claim 11
Dependent Claim
25 words
An electrostatic photographic copying process according to claim 8 wherein said copolymer has a weight average molecular weight in the range of 75,000 to 150,000.
Claim 12
Dependent Claim
31 words
An electrostatic photographic copying process according to claim 10 wherein the copolymer comprises from 45 to 93% by weight of the aromatic vinyl monomer (a) based on the total binder medium.
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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) | 1985-02-08 | 1985-08-10 | 1986-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-08 | 1989-08-10 | 1990-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-08 | 1993-08-10 | 1994-02-09 | $7700.00 | Window Closed / Lapsed |