Patent US4590141A successfully refreshed from Google Patents.
US4590141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carrier particles for use in a two-component dry-type developer for developing latent electrostatic images
Assignee: Ricoh Co Ltd
•
Filing: 1984-10-19
•
Granted: 1986-05-20
•
Expires: 2004-10-19
Abstract
Abstract Carrier particles are disclosed for use in a two-component dry-type developer for developing latent electrostatic images to visible images, for use in electrophotography, electrostatic recording methods and electrostatic printing methods, which carrier particles are coated with a silicone resin coating layer having high resistance to abrasion and the so-called "spent phenomenon" while in use, and which therefore can be used repeatedly for a long period of time, yielding developed images with high quality. The high resistance to abrasion of the silicone resin coating layer is attained by adding to the silicone coating layer, as an inorganic fortifying agent against abrasion, silicon carbide or potassium titanate.
Inventors
- 👤 Mitsuo Aoki
- 👤 Satoru Inoue
- 👤 Kimitoshi Yamaguchi
- 👤 Mitsuru Uchida
- 👤 Masami Tomita
- 👤 Chiaki Uematsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:43
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1135; G03G9/1136
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
68 words
Carrier particles for use in a two-component dry-type developer for developing latent electrostatic images to visible images, comprising a core material and a silicone resin layer coated on the surface of said core material, said silicone resin layer comprising a silicone resin and, as a fortifying agent against abrasion of said carrier particles, inorganic fortifying filler particles selected from the group consisting of silicon carbide and potassium titanate.
Claim 2
Dependent Claim
68 words
Carrier particles for use in a two-component dry-type developer for developing latent electrostatic images to visible images, comprising a core material and a silicone resin layer coated on the surface of said core material, said silicone resin layer comprising a silicone resin and, as a fortifying agent against abrasion of said carrier particles, inorganic fortifying filler particles selected from the group consisting of silicon carbide and potassium titanate.
Claim 3
Dependent Claim
55 words
Carrier particles as claimed in claim 1, wherein the amount of said inorganic fortifying filler particles is in the range of 5 wt.% to 50 wt.% of the total weight of said silicone resin layer, and the average particle size of said inorganic fortifying filler is in the range of 0.1 μm to 1.0 μm.
Claim 4
Dependent Claim
44 words
Carrier particles as claimed in claim 1, wherein said core material is selected from the group consisting of particles of sand, cobalt, iron, iron oxide, copper, nickel, zinc, aluminum, brass and glass, having an average particle size ranging from 20 μm to 1000 μm.
Claim 5
Dependent Claim
46 words
Carrier particles as claimed in claim 1, wherein said silicone resin is a room-temperature-setting type silicone resin of the formula ##STR4## wherein R represents hydrogen, halogen, a hydroxy group, a methoxy group, a lower alkyl group with 1 to 4 carbon atoms, or a phenyl group.
Claim 6
Dependent Claim
47 words
A two-component developer for developing latent electrostatic images to visible images comprising toner particles and carrier particles coated with a silicone resin layer containing as a fortifying agent against abrasion inorganic fortifying filler particles selected from the group consisting of particles of silicon carbide and potassium titanate.
Claim 7
Dependent Claim
47 words
A two-component developer for developing latent electrostatic images to visible images comprising toner particles and carrier particles coated with a silicone resin layer containing as a fortifying agent against abrasion inorganic fortifying filler particles selected from the group consisting of particles of silicon carbide and potassium titanate.
Claim 8
Dependent Claim
100 words
A two-component developer for developing latent electrostatic images to visible images comprising toner particles and carrier particles coated with a silicone resin layer containing as a fortifying agent against abrasion inorganic fortifying filler particles selected from the group consisting of particles of silicon carbide and potassium titanate, wherein said toner particles contain as a charge polarity control agent a monoazo metal complex dye of the following formula: ##STR5## wherein X, Y and Z independently represent hydrogen, halogen, carboxyl, hydroxyl, nitro, sulfo or sulfonamide; and A + represents H + , K + , Na + or an aliphatic ammonium cation.
Claim 9
Dependent Claim
100 words
A two-component developer for developing latent electrostatic images to visible images comprising toner particles and carrier particles coated with a silicone resin layer containing as a fortifying agent against abrasion inorganic fortifying filler particles selected from the group consisting of particles of silicon carbide and potassium titanate, wherein said toner particles contain as a charge polarity control agent a monoazo metal complex dye of the following formula: ##STR5## wherein X, Y and Z independently represent hydrogen, halogen, carboxyl, hydroxyl, nitro, sulfo or sulfonamide; and A + represents H + , K + , Na + or an aliphatic ammonium cation.
Claim 10
Dependent Claim
145 words
Carrier particles for use in a developer for developing electrostatic latent images, said carrier particles being adapted to carry toner particles on the surfaces of said carrier particles, comprising core particles having an average particle size in the range of 20 to 1000 μm selected from the group consisting of particles of sand, cobalt, iron, iron oxide, copper, nickel, zinc, aluminum, brass and glass, and a coating layer covering each of said core particles, said coating layer consisting essentially of a silicone resin containing dispersed therein filler particles of silicon carbide or potassium titanate, said coating layer having been prepared by coating said core particles with a liquid dispersion of said filler particles dispersed in a solvent solution of said silicone resin and then drying the coating, said filler particles being effective to prevent removal of said coating layer during use of said carrier particles.
Claim 11
Dependent Claim
145 words
Carrier particles for use in a developer for developing electrostatic latent images, said carrier particles being adapted to carry toner particles on the surfaces of said carrier particles, comprising core particles having an average particle size in the range of 20 to 1000 μm selected from the group consisting of particles of sand, cobalt, iron, iron oxide, copper, nickel, zinc, aluminum, brass and glass, and a coating layer covering each of said core particles, said coating layer consisting essentially of a silicone resin containing dispersed therein filler particles of silicon carbide or potassium titanate, said coating layer having been prepared by coating said core particles with a liquid dispersion of said filler particles dispersed in a solvent solution of said silicone resin and then drying the coating, said filler particles being effective to prevent removal of said coating layer during use of said carrier particles.
Claim 12
Dependent Claim
40 words
Carrier particles as claimed in claim 7, wherein said silicone resin is a room-temperature-setting type silicone resin containing units of the formula ##STR6## wherein R represents hydrogen, halogen, hydroxy, methoxy, lower alkyl having 1 to 4 carbon atoms, or phenyl.
Claim 13
Dependent Claim
48 words
Carrier particles as claimed in claim 8, wherein said core particles have an average particle size range in the range of 50 to 500 μm, and said coating layer is heated to a temperature in the range of 200° C. to 300° C. to harden said silicone resin.
Claim 14
Dependent Claim
133 words
A developer as claimed in claim 5, wherein said carrier particles consist essentially of core particles having an average particle size in the range of 20 to 1000 μm selected from particles of sand, cobalt, iron, iron oxide, copper, nickel, zinc, aluminum, brass and glass, and said silicone resin layer consists essentially of a silicone resin containing not more than 30 wt.% of unhardened silicone resin, and from 5 to 50 wt.%, based on the total weight of said coating layer, of said filler particles made of silicon carbide or potassium titanate, said filler particles having an average particle size in the range of 0.1 μm to 1.0 μm and wherein said toner particles are mixed with said carrier particles and cover 30% to 90% of the silicone-coated surface of said carrier particles.
Claim 15
Dependent Claim
25 words
A developer as claimed in claim 6, wherein said toner particles consist essentially of a resin, a coloring agent, and said monoazo metal complex dye.
Claim 16
Dependent Claim
19 words
A developer as claimed in claim 11, wherein said resin is polystyrene and said coloring agent is carbon black.
Claim 17
Dependent Claim
28 words
A developer as claimed in claim 10, wherein said toner particles have 0.2 to 2.0 wt.% of a surface lubricating polymer on the surfaces of said toner particles.
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) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |