US4927728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carrier particles for use in a two-component dry-type developer
Assignee: Ricoh Co Ltd
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Filing: 1988-11-23
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Granted: 1990-05-22
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Expires: 2008-11-23
Abstract
Abstract The disclosure describes carrier particles for use in a two-component dry-type developer, consisting of core particles which are coated with a silicone resin hardened by an organic tin catalyst.
Inventors
- 👤 Tetsuo Isoda
- 👤 Yoichiro Watanabe
- 👤 Nobuhiro Nakayama
- 👤 Mitsuo Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:51
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1137; G03G9/1135; G03G9/1136; Y; Y10; Y10S; Y10S524/00; Y10S524/908; Y10S525/00; Y10S525/934; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
182 words
Carrier particles for use in two-component dry-type developers for electrophotography, comprising: core particles coated with a hardened silicone resin having a three-dimensional network structure comprised of Si-O-Si bonds, said core particles being made of a material selected from the group consisting of a magnetic metal, a non-magnetic metal and a non-metallic material, with the particle size thereof being in the range of 30 μm to 1,000 μm, said carrier particles having been prepared by dissolving an organosiloxane capable of forming said silicone resin and an organic tin catalyst capable of catalyzing hardening of said silicone resin in an organic solvent to form a silicone varnish, then coating said core particles with said varnish and drying said varnish to form coatings on said core particles, then heating said coated core particles at a temperature in the range of about 100° C. to about 250° C. to harden the silicone resin, said organic tin catalyst being selected from the group consisting of: (No. 1) R 2 Sn(OCOR') 2 wherein R and R' each represent an alkyl group of C 1 ˜C 12 . ##STR3##
Claim 2
Dependent Claim
182 words
Carrier particles for use in two-component dry-type developers for electrophotography, comprising: core particles coated with a hardened silicone resin having a three-dimensional network structure comprised of Si-O-Si bonds, said core particles being made of a material selected from the group consisting of a magnetic metal, a non-magnetic metal and a non-metallic material, with the particle size thereof being in the range of 30 μm to 1,000 μm, said carrier particles having been prepared by dissolving an organosiloxane capable of forming said silicone resin and an organic tin catalyst capable of catalyzing hardening of said silicone resin in an organic solvent to form a silicone varnish, then coating said core particles with said varnish and drying said varnish to form coatings on said core particles, then heating said coated core particles at a temperature in the range of about 100° C. to about 250° C. to harden the silicone resin, said organic tin catalyst being selected from the group consisting of: (No. 1) R 2 Sn(OCOR') 2 wherein R and R' each represent an alkyl group of C 1 ˜C 12 . ##STR3##
Claim 3
Dependent Claim
110 words
Carrier particles as claimed in claim 1, wherein said silicone resin is a polymeric material comprising an organopolysiloxane with a three-dimensional network structure containing Si-O-Si bonds as the main chain, represented by the formula ##STR4## wherein some of the Rs represent a group selected from the group consisting of a lower alkyl group, a phenyl group, an alkyd-modified-, an acryl-modified-, an epoxy-modified-, an amino-modified-, a carboxy-modified-, an alcohol-modified-, a fluorine-modified-, a polyether-modified-, an urethane-modified-, a nitrile-modified-, a polyester-modified-lower alkyl group or -phenyl group, and the remainder of the Rs represent a group selected from the group consisting of hydrogen, a lower alkoxy group, a hydroxyl group and a vinyl group.
Claim 4
Dependent Claim
36 words
Carrier particles as claimed in claim 1, wherein the amount of said organic tin catalyst is in the range of from 0.1 wt. % to 3 wt. % of the non-volatile components of said silicone resin.
Claim 5
Dependent Claim
27 words
Carrier particles as claimed in claim 1, wherein said core particles are coated with said silicone resin with a thickness ranging from 0.1 μm to 20 μm.
Claim 6
Dependent Claim
17 words
Carrier particles as claimed in claim 1, in which said organic tin catalyst is dibutyl tin dilaurate.
Claim 7
Dependent Claim
161 words
Carrier particles for use in two-component dry-type developers for electrophotography, comprising: core particles having a particle size in the range of from 30 μm to 1000 μm and coated with a layer consisting essentially of a hardened silicone resin having a three-dimensional network structure consisting essentially of Si-O-Si bonds, said carrier particles having been prepared by dissolving methylpolysiloxane capable of forming said silicon resin and an organic tin catalyst capable of catalyzing hardening of said methylpolysiloxane in an organic solvent to form a silicone varnish, then coating said core particles with said varnish and drying said varnish to form coatings on said core particles, then heating said coated core particles at a temperature in the range of about 100° C. to about 250° C. to harden the silicone resin, said organic tin catalyst being selected from the group consisting of: R 2 Sn(OCOR') 2 wherein R and R' each represent an alkyl group of C 1 to C 12 . ##STR5##
Claim 8
Dependent Claim
161 words
Carrier particles for use in two-component dry-type developers for electrophotography, comprising: core particles having a particle size in the range of from 30 μm to 1000 μm and coated with a layer consisting essentially of a hardened silicone resin having a three-dimensional network structure consisting essentially of Si-O-Si bonds, said carrier particles having been prepared by dissolving methylpolysiloxane capable of forming said silicon resin and an organic tin catalyst capable of catalyzing hardening of said methylpolysiloxane in an organic solvent to form a silicone varnish, then coating said core particles with said varnish and drying said varnish to form coatings on said core particles, then heating said coated core particles at a temperature in the range of about 100° C. to about 250° C. to harden the silicone resin, said organic tin catalyst being selected from the group consisting of: R 2 Sn(OCOR') 2 wherein R and R' each represent an alkyl group of C 1 to C 12 . ##STR5##
References Cited (Backward Citations)
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