EP0662643A2
Expired / Lapsed
EP
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Carrier for use in electrophotography
Assignee: Canon Inc
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Filing: 1994-12-23
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Granted: —
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Expires: 2014-12-23
Abstract
Abstract A carrier for use in electrophotography has carrier particles. The carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10<1><0> OMEGA .cm or above under conditions of a temperature of 23 DEG C and a humidity of 50%RH. The carrier particles have an average particle diameter of not larger than 100 mu m and a resistivity of 10<1><0> OMEGA .cm or above. The carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%. <IMAGE>
Inventors
- 👤 Shinya C/O Canon K.K. Mayama
- 👤 Yuko C/O Canon K.K. Sato
- 👤 Hiroshi C/O Canon K.K. Aoto
- 👤 Hitoshi C/O Canon K.K. Itabashi
- 👤 Takeshi C/O Canon K.K. Ikeda
- 👤 Yoshinobu C/O Canon K.K. Baba
- 👤 Yasuko C/O Canon K.K. Hayashi
- 👤 Yuzo C/O Canon K.K. Tokunaga
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:08
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/107; G03G9/1075; G03G9/113; G03G9/1132
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
107 words
A carrier for use in electrophotography, comprising carrier particles, wherein; said carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10¹⁰ Ω·cm or above under conditions of a temperature of 23°C and a humidity of 50%RH; said carrier particles have an average particle diameter of not larger than 100 µm; said carrier particles have a resistivity of 10¹⁰ Ω·cm or above; and said carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%.
Claim 2
Dependent Claim
29 words
The carrier according to claim 1, wherein said resin has a resistivity of 10¹³ Ω·cm or above, and said carrier particles have a resistivity of 10¹² Ω·cm or above.
Claim 3
Dependent Claim
33 words
The carrier according to claim 1 or 2, wherein said carrier particles comprise not less than 90% by number of the resin-coated carrier particles having the resin coverage of not less than 90%.
Claim 4
Dependent Claim
32 words
The carrier according to claim 1 or 2, wherein said carrier particles comprise not less than 60% by number of resin-coated carrier particles having a resin coverage of not less than 95%.
Claim 5
Dependent Claim
23 words
The carrier according to any preceding claim, wherein said carrier particles have an average particle diameter of from 10 µm to 60 µm.
Claim 6
Dependent Claim
27 words
The carrier according to any preceding claim, wherein said carrier core particle comprises a magnetic material and has a resistivity of from 10⁵ Ω·cm to 10¹⁰ Ω·cm.
Claim 7
Dependent Claim
21 words
The carrier according to claim 6, wherein said carrier core particle has a resistivity of from 10⁵ Ω·cm to 10⁹ Ω·cm.
Claim 8
Dependent Claim
21 words
The carrier according to any preceding claim, wherein said carrier core particle is a magnetic material disperse type resin core particle.
Claim 9
Dependent Claim
30 words
The carrier according to any preceding claim, wherein said carrier core particle is coated with the resin in a coating weight of from 0.5% by weight to 15% by weight.
Claim 10
Dependent Claim
29 words
The carrier according to claim 9, wherein said carrier core particle is coated with the resin in a coating weight of from 0.6% by weight to 10% by weight.
Claim 11
Dependent Claim
45 words
The carrier according to any preceding claim, wherein said carrier core particle is coated with the resin so as to satisfy the following expression: 2.5/X ≦ resin coating weight (% by weight) ≦ 75/X wherein X represents a true specific gravity of carrier core particles.
Claim 12
Dependent Claim
33 words
The carrier according to claim 11, wherein said carrier core particle is coated with the resin so as to satisfy the following expression: 3/X ≦ resin coating weight (% by weight) ≦ 50/X.
Claim 13
Dependent Claim
25 words
The carrier according to any preceding claim, wherein said carrier particles have a magnetization intensity of from 30 emu/cm³ to 250 emu/cm³ at 1,000 oersteds.
Claim 14
Dependent Claim
24 words
The carrier according to claim 13, wherein said carrier particles have a magnetization intensity of from 40 emu/cm³ to 250 emu/cm³ at 1,000 oersteds.
Claim 15
Dependent Claim
24 words
The carrier according to claim 14, wherein said carrier particles have a magnetization intensity of from 40 emu/cm³ to 100 emu/cm³ at 1,000 oersteds.
Claim 16
Dependent Claim
65 words
The carrier according to any preceding claim, wherein said carrier particles satisfy the following condition. 0.08 emu/cm² < KP < 1.0 emu/cm² wherein KP represents an image quality improvement parameter KP = I x D; wherein I represents a magnetizing force in a unit of emu/cm³, of a magnetic material used in the carrier, and D represents carrier particle diameter in a unit of cm.
Claim 17
Dependent Claim
21 words
The carrier according to claim 16, wherein said carrier particles satisfy the following condition. 0.1 emu/cm² < KP < 0.8 emu/cm².
Claim 18
Dependent Claim
19 words
The carrier according to any preceding claim, wherein said carrier particles has a sphericity SF-1 of 2 or below.
Claim 19
Dependent Claim
183 words
A process for producing a carrier, comprising the steps of; forming a fluidized bed of carrier core particles in a tubular body by the aid of a gas flow ascending inside the tubular body; and spraying a coating resin solution in the direction perpendicular to or substantially perpendicular to the direction the carrier core particles ascend in the fluidized bed; said coating resin solution being sprayed at a spray pressure of 1.5 kg/cm² or above; to produce a resin-coated carrier, wherein; said carrier comprises carrier particles; said carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10¹⁰ Ω·cm or above under conditions of a temperature of 23°C and a humidity of 50%RH; said carrier particles have an average particle diameter of not larger than 100 µm; said carrier particles have a resistivity of 10¹⁰ Ω·cm or above; and said carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%.
Claim 20
Dependent Claim
40 words
The process according to claim 19, wherein said carrier core particles are sprayed with said resin solution while being agitated by a rotary bottom disk plate and an agitating blade which are provided at the bottom of said tubular body.
Claim 21
Dependent Claim
29 words
The process according to claim 20, wherein said rotary bottom disk plate has a mesh, and air is blown off through the mesh to fluidize said carrier core particles.
Claim 22
Dependent Claim
33 words
The process according to claim 19, 20 or 21 wherein said carrier core particles are sprayed with said resin solution to produce the carrier according to any one of claims 2 to 18.
Claim 23
Dependent Claim
128 words
A two-component type developer for developing an electrostatic image, comprising toner particles and carrier particles, wherein; said toner particles have a weight average particle diameter of not larger than 10 µm; said carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10¹⁰ Ω·cm or above under conditions of a temperature of 23°C and a humidity of 50%RH; said carrier particles have an average particle diameter of not larger than 100 µm; said carrier particles have a resistivity of 10¹⁰ Ω·cm or above; and said carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%.
Claim 24
Dependent Claim
24 words
The two-component type developer according to claim 23, wherein said carrier particles are the carrier according to any one of claims 2 to 18.
Claim 25
Dependent Claim
24 words
The two-component type developer according to claim 24, wherein said toner particles have a weight average particle diameter of from 3µm to 8 µm.
Claim 26
Dependent Claim
29 words
The two-component type developer according to claim 23, wherein said toner particles are contained in said developer in a concentration of from 1% by weight to 20% by weight.
Claim 27
Dependent Claim
29 words
The two-component type developer according to claim 26, wherein said toner particles are contained in said developer in a concentration of from 1% by weight to 10% by weight.
Claim 28
Dependent Claim
178 words
An image forming method comprising; forming an electrostatic image on an electrostatic image bearing member; forming on a developer carrying member a magnetic brush formed of a two-component type developer; and developing the electrostatic image through the magnetic brush while applying a bias voltage to the developer carrying member, to form a toner image; wherein; said two-component type developer comprises toner particles and magnetic carrier particles; said toner particles have a weight average particle diameter of not larger than 10 µm; said carrier particles each comprise a carrier core particle and a resin for coating the carrier core particle and having a resistivity of 10¹⁰ Ω·cm or above under conditions of a temperature of 23°C and a humidity of 50%RH; said carrier particles have an average particle diameter of not larger than 100 µm; said carrier particles have a resistivity of 10¹⁰ Ω.cm or above; and said carrier particles comprise not less than 80% by number of resin-coated carrier particles whose carrier core particles are each coated with a resin in a coverage of not less than 90%.
Claim 29
Dependent Claim
25 words
The image forming method according to claim 28, wherein said magnetic carrier particles are the carrier according to any one of claims 2 to 18.
Claim 30
Dependent Claim
25 words
The image forming method according to claim 29, wherein said toner particles have a weight average particle diameter of from 3 µm to 8 µm.
Claim 31
Dependent Claim
19 words
The image forming method according to claim 28, wherein an alternating voltage is applied to said developer carrying member.
Claim 32
Dependent Claim
20 words
The image forming method according to claim 31, wherein said alternating voltage has a Vpp of from 1,000 to 10,000.
Claim 33
Dependent Claim
20 words
The image forming method according to claim 32, wherein said alternating voltage has a Vpp of from 2,000 to 8,000.
Claim 34
Dependent Claim
26 words
A carrier for use in electrophotography comprising carrier particles coated in sufficient number and completeness with a resistivity-enhancing coating resin to reduce or prevent carrier adhesion.
References Cited (Backward Citations)
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