US4181620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid developer for use in electrophotography
Assignee: Ricoh Co Ltd
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Filing: 1977-09-09
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Granted: 1980-01-01
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Expires: 1997-09-09
Abstract
Abstract A liquid developer for use in electrophotography, which is superior in storage stability and transferability, said developer comprising a resin A and a coloring agent dispersed in a carrier liquid having a high electric resistivity and a low dielectric constant, said coloring agent having a high electric resistivity and consisting essentially of fine particles of pigment coated with a resin B which is different from said resin A and is substantially insoluble in said carrier liquid.
Inventors
- 👤 Kazuo Tsubuko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:57
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/12; G03G9/13; G03G9/132; G03G9/133
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
299 words
A liquid developer for use in electrophotography comprising coloring agent particles and an A resin dispersed in a carrier liquid having a high electric resistivity and a low dielectric constant, said coloring agent particles having an average particle size in the range of from 0.01 to 20 microns and having an electric resistivity of about 10 8 to 10 14 Ωcm, said coloring agent particles consisting essentially of fine pigment particles substantially completely coated with B resin which is substantially insoluble in said carrier liquid, said coloring agent particles having been prepared by kneading an aqueous paste of pigment with an organic solvent solution of said B resin to displace the water from the pigment and to replace it by said solution of said B resin, followed by removing water and said solvent and then pulverizing the resulting dry solids, said A resin being a non-aqueous thermoplastic resin prepared by effecting graft polymerization between (a) a copolymer of (i) monomer having the formula ##STR4## wherein R is H or CH 3 , and X is COOC n H 2n+1 or OC n H 2n+1 and 6≦n≦20, and (ii) glycidyl acrylate or glycidyl methacrylate, or (iii) unsaturated carboxylic acid or unsaturated carboxylic acid anhydride, and (b) a first grafting monomer which is an unsaturated carboxylic acid or unsaturated carboxylic acid anhydride when said copolymer has been prepared using glycidyl acrylate or glycidyl methacrylate, or which is glycidyl acrylate or glycidyl methacrylate when said copolymer has been prepared using said unsaturated carboxylic acid or unsaturated carboxylic acid anhydride, and then further grafting a second grafting monomer selected from the group consisting of ##STR5## wherein R has the same meaning as defined above, and Y is ##STR6## and ##STR7## wherein R has the same meaning as defined above, and Z is ##STR8##
Claim 2
Dependent Claim
299 words
A liquid developer for use in electrophotography comprising coloring agent particles and an A resin dispersed in a carrier liquid having a high electric resistivity and a low dielectric constant, said coloring agent particles having an average particle size in the range of from 0.01 to 20 microns and having an electric resistivity of about 10 8 to 10 14 Ωcm, said coloring agent particles consisting essentially of fine pigment particles substantially completely coated with B resin which is substantially insoluble in said carrier liquid, said coloring agent particles having been prepared by kneading an aqueous paste of pigment with an organic solvent solution of said B resin to displace the water from the pigment and to replace it by said solution of said B resin, followed by removing water and said solvent and then pulverizing the resulting dry solids, said A resin being a non-aqueous thermoplastic resin prepared by effecting graft polymerization between (a) a copolymer of (i) monomer having the formula ##STR4## wherein R is H or CH 3 , and X is COOC n H 2n+1 or OC n H 2n+1 and 6≦n≦20, and (ii) glycidyl acrylate or glycidyl methacrylate, or (iii) unsaturated carboxylic acid or unsaturated carboxylic acid anhydride, and (b) a first grafting monomer which is an unsaturated carboxylic acid or unsaturated carboxylic acid anhydride when said copolymer has been prepared using glycidyl acrylate or glycidyl methacrylate, or which is glycidyl acrylate or glycidyl methacrylate when said copolymer has been prepared using said unsaturated carboxylic acid or unsaturated carboxylic acid anhydride, and then further grafting a second grafting monomer selected from the group consisting of ##STR5## wherein R has the same meaning as defined above, and Y is ##STR6## and ##STR7## wherein R has the same meaning as defined above, and Z is ##STR8##
Claim 3
Dependent Claim
30 words
A liquid developer according to claim 1 in which the amount of said B resin is from 0.5 to 5 parts by weight, per 1 part by weight of pigment.
Claim 4
Dependent Claim
13 words
A liquid developer according to claim 1, wherein said pigment is carbon black.
Claim 5
Dependent Claim
19 words
A liquid developer according to claim 1, wherein said pigment is an organic pigment or mixture of organic pigments.
Claim 6
Dependent Claim
19 words
A liquid developer according to claim 1, wherein said pigment is a mixture of organic pigment with carbon black.
Claim 7
Dependent Claim
43 words
A liquid developer according to claim 1, wherein said resin B is a member selected from the group consisting of natural resin-modified phenol resin, natural resin-modified maleic resin, dammar, copal, shellac, gum rosin, hardened rosin, ester gum, glycerin-modified maleic resin, and mixtures thereof.
Claim 8
Dependent Claim
85 words
A liquid developer according to claim 1, wherein said coloring agent additionally contains a polarity controlling polymer having a monomer unit selected from the group consisting of unsaturated carboxylic acid and vinyl monomer, said polymer having been prepared by incorporating from 1×10 -3 to 0.1 part by weight of said monomer, per 1 part by weight of said pigment, and a polymerization initiator in the mixture of pigment particles and B resin in the kneading step so that said monomer polymerizes during the kneading step.
Claim 9
Dependent Claim
65 words
A liquid developer according to claim 7, wherein said unsaturated carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, itaconic acid, crotonic acid and maleic acid, and said vinyl monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, styrene, chlorostyrene, vinyl acetate, acrylonitrile, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide and N-vinyl pyrrolidone.
Claim 10
Dependent Claim
35 words
A liquid developer according to claim 1, wherein said nonaqueous thermoplastic resin is prepared by adding and dissolving wax-like material in any one of the manufacturing steps thereof and cooling after performing the final step.
Claim 11
Dependent Claim
39 words
A liquid developer according to claim 9, wherein the wax-like material is at least one substance selected from the group consisting of paraffin wax and polyethylene having a softening point in the range of from 60° to 130° C.
Claim 12
Dependent Claim
42 words
A liquid developer according to claim 1, wherein at least one member selected from the group consisting of acrylic resin, styrene resin, alkyd resin, cyclized rubber, chlorinated rubber, cellulose derivative, styrene-butadiene copolymer and vinyl-toluene-butadiene copolymer is added to said non-aqueous thermoplastic resin.
Claim 13
Dependent Claim
28 words
A liquid developer according to claim 11, wherein the ratio of said member to said non-aqueous thermoplastic resin is in the range of 1:1 to 20% by weight.
Claim 14
Dependent Claim
34 words
A liquid developer according to claim 1 in which said carrier liquid is an aliphatic hydrocarbon having an electric resistivity of more than 10 9 Ω.cm and a dielectric constant of less than 3.
Claim 15
Dependent Claim
293 words
A liquid developer according to claim 13 wherein said A resin component is a non-aqueous thermoplastic resin latex prepared by carrying out successively the following three steps (a), (b) and (c) in an aliphatic hydrocarbon or halogenated aliphatic hydrocarbon solvent (a) copolymerizing from 99.9 to 80 parts by weight of a monomer having the formula ##STR9## wherein R is as defined above and X is --COOC n H 2n+1 or --OC n H 2n+1 wherein n is from 6 to 20, with from 0.1 to 20 parts by weight of a co-monomer selected from the group consisting of an unsaturated carboxylic acid, glycidyl acrylate and glycidyl methacrylate (b) esterifying 100 parts by weight of the copolymer obtained in step (a) with from 0.1 to 20 parts by weight of glycidyl acrylate or glycidyl methacrylate when said copolymer has been prepared by using an unsaturated carboxylic acid, or esterifying 100 parts by weight of the copolymer obtained in step (a) with from 0.1 to 20 parts by weight of said unsaturated carboxylic acid when said copolymer has been prepared by using glycidyl acrylate or glycidyl methacrylate; and (c) grafting 100 parts by weight of the esterified copolymer obtained in step (b) with from 5 to 100 parts by weight of at least one monomer selected from the group consisting of a monomer having the formula ##STR10## wherein R is as defined above and Y is --COOC n' H 2n'+1 wherein n' is 1 to 4, --OCOC m H 2m+1 wherein m is 1 to 6, ##STR11## and monomer having the formula ##STR12## wherein R is as defined above and Z is --COOC 2 H 4 N(C n' H 2n'+1 ) 2 wherein n' is as defined above, --COOH, --COOC 2 H 4 OH, ##STR13##
Claim 16
Dependent Claim
16 words
A liquid developer according to claim 1 wherein said B resin is natural resin-modified phenol resin.
Claim 17
Dependent Claim
16 words
A liquid developer according to claim 1 wherein said B resin is natural resin-modified maleic resin.
Claim 18
Dependent Claim
13 words
A liquid developer according to claim 1 wherein said B resin is dammar.
Claim 19
Dependent Claim
13 words
A liquid developer according to claim 1 wherein said B resin is copal.
Claim 20
Dependent Claim
13 words
A liquid developer according to claim 1 wherein said B resin is shellac.
Claim 21
Dependent Claim
14 words
A liquid developer according to claim 1 wherein said B resin is gum rosin.
Claim 22
Dependent Claim
14 words
A liquid developer according to claim 1 wherein said B resin is hardened rosin.
Claim 23
Dependent Claim
14 words
A liquid developer according to claim 1 wherein said B resin is ester gum.
Claim 24
Dependent Claim
15 words
A liquid developer according to claim 1 wherein said B resin is glycerin-modified maleic resin.
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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) | 1982-12-31 | 1983-07-02 | 1984-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-31 | 1987-07-02 | 1988-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-31 | 1991-07-02 | 1992-01-01 | $7700.00 | Window Closed / Lapsed |