EP0650097A1
Expired / Lapsed
EP
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Magnetic toner, process cartridge and image forming method
Assignee: Canon Inc
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Filing: 1994-10-06
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Granted: —
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Expires: 2014-10-06
Abstract
Abstract A magnetic toner is formed from a binder resin and silicon-containing magnetic iron oxide particles. The magnetic toner has a weight-average particle size of at most 13.5 µm, and the magnetic toner has a particle size distribution such that magnetic toner particles having a particle size of at least 12.7 µm are contained in an amount of at most 50 wt. %. The magnetic iron oxide particles have a silicon content of 0.4 - 2.0 wt. % based on iron, and the magnetic iron oxide particles have an Fe/Si atomic ratio of 1.2 - 4.0 at the utmost surfaces thereof. Because of the use of such magnetic iron oxide particles having a specifically controlled overall and surface Si contents, the magnetic toner can show stable performances even after standing in a high humidity environment.
Inventors
- 👤 Takashige C/O Canon K.K. Kasuya
- 👤 Hiroyuki C/O Canon K.K. Suematsu
- 👤 Koichi C/O Canon K.K. Tomiyama
- 👤 Hiroshi C/O Canon K.K. Yusa
- 👤 Takakuni C/O Canon K.K. Kobori
- 👤 Masaichiro C/O Canon K.K. Katada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 05:50
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/097; G03G9/09733; G03G9/09775; G03G9/0819; G03G9/0831; G03G9/0833; G03G9/0834; G03G9/0836; G03G9/0837; G03G9/0838; G03G9/09; G03G9/0906; G03G9/091; G03G9/09783
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
101 words
A magnetic toner, comprising magnetic toner particles containing a binder resin and magnetic iron oxide particles; wherein the magnetic toner has a weight-average particle size of at most 13.5 µm, the magnetic toner has a particle size distribution such that magnetic toner particles having a particle size of at least 12.7 µm are contained in an amount of at most 50 wt. %, the magnetic iron oxide particles have a silicon content of 0.4 - 2.0 wt. % based on iron, and the magnetic iron oxide particles have an Fe/Si atomic ratio of 1.2 - 4.0 at the utmost surfaces thereof.
Claim 2
Dependent Claim
20 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a smoothness of 0.3 - 0.8.
Claim 3
Dependent Claim
22 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a bulk density of at least 0.8 g/cm³.
Claim 4
Dependent Claim
24 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a BET specific surface area of at most 15.0 m²/g.
Claim 5
Dependent Claim
31 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have been treated with aluminum hydroxide in an amount of 0.01 - 2.0 wt. % calculated as aluminum.
Claim 6
Dependent Claim
27 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have an Fe/Al atomic ratio of 0.3 - 10.0 at the utmost surfaces thereof.
Claim 7
Dependent Claim
39 words
The magnetic toner according to Clam 1, wherein the magnetic iron oxide particles have a smoothness of 0.3 - 0.8, a bulk density of at least 0.8 g/cm³ and a BET specific surface area of at most 15.0 m²/g.
Claim 8
Dependent Claim
20 words
The magnetic toner according to Claim 7, wherein the magnetic iron oxide particles have been treated with an aluminum compound.
Claim 9
Dependent Claim
31 words
The magnetic toner according to Claim 8, wherein the magnetic iron oxide particles have been treated with aluminum hydroxide in an amount of 0.01 - 2.0 wt. % calculated as aluminum.
Claim 10
Dependent Claim
27 words
The magnetic toner according to Claim 8, wherein the magnetic iron oxide particles have an Fe/Al atomic ratio of 0.3 - 10.0 at the utmost surfaces thereof.
Claim 11
Dependent Claim
41 words
The magnetic toner according to Claim 1, wherein the magnetic toner has a weight-average particle size of 3.5 - 13.5 µm and contains at most 40 wt. % of magnetic toner particles having a particle size of at least 12.7 µm.
Claim 12
Dependent Claim
41 words
The magnetic toner according to Claim 11, wherein the magnetic toner has a weight-average particle size of 4.0 - 11.0 µm and contains at most 30 wt. % of magnetic toner particles having a particle size of at least 12.7 µm.
Claim 13
Dependent Claim
26 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a silicon content of 0.5 - 0.9 wt. % based on iron.
Claim 14
Dependent Claim
46 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have been treated with aluminum hydroxide in an amount of 0.05 - 1.0 wt. % calculated as aluminum and have an Fe/Al atomic ratio of 0.3 - 5.0 at the utmost surfaces thereof.
Claim 15
Dependent Claim
27 words
The magnetic toner according to Claim 14, wherein the magnetic iron oxide particles have an Fe/Al atomic ratio of 0.3 - 2.0 at the utmost surfaces thereof.
Claim 16
Dependent Claim
48 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a smoothness of 0.45 - 0.7, a bulk density of at least 1.0 g/cm³, a BET specific surface area of at most 12.0 m²/g, and an average particle size of 0.1 - 0.4 µm.
Claim 17
Dependent Claim
30 words
The magnetic toner according to Claim 16, wherein the magnetic iron oxide particles have a smoothness of 0.5 - 0.7 and an average particle size of 0.1 - 0.3 µm.
Claim 18
Dependent Claim
24 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a total surface pore volume of 7.0x10⁻³ - 15.0x10⁻³ ml/g.
Claim 19
Dependent Claim
24 words
The magnetic toner according to Claim 18, wherein the magnetic iron oxide particles have a total surface pore volume of 8.0x10⁻³ - 12.0x10⁻³ ml/g.
Claim 20
Dependent Claim
54 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a surface pore distribution such that micro-pores having a pore diameter smaller than 20 Å provide a total specific surface area which is equal to or smaller than that of mesa-pores having a pore diameter of at least 20 Å.
Claim 21
Dependent Claim
73 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles have a moisture content of 0.4 - 1.0 wt. % at a temperature of 23.5 o C and a humidity of 65 % RH, and a moisture content of 0.6 - 1.5 wt. % at a temperature of 32.5 o C and a humidity of 85 % RH, the moisture contents providing a difference therebetween not exceeding 0.6 wt. %.
Claim 22
Dependent Claim
73 words
The magnetic toner according to Claim 21, wherein the magnetic iron oxide particles have a moisture content of 0.45 - 0.90 wt. % at a temperature of 23.5 o C and a humidity of 65 % RH, and a moisture content of 0.6 - 1.10 wt. % at a temperature of 32.5 o C and a humidity of 85 % RH, the moisture contents providing a difference therebetween not exceeding 0.3 wt. %.
Claim 23
Dependent Claim
20 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles further contain a negative charge control agent.
Claim 24
Dependent Claim
109 words
The magnetic toner according to Claim 23, wherein the magnetic charge control agent is a monoazo iron complex salt represented by the following formula: wherein X₁ and X₂ independently denote hydrogen, lower alkyl, lower alkoxy, nitro or halogen; m and m' independently denote an integer of 1 - 3; Y₁ and Y₃ independently denote hydrogen, C₁ - C₁₈ alkyl, C₂ - C₁₈ alkenyl, sulfonamide, mesyl, sulfonic acid, carboxy ester, hydroxy, C₁ - C₁₈ alkoxy, C₂ - C₁₈ acetylamino, benzoyl, amino or halogen; n and n' independently denote an integer of 1 - 3; Y₂ and Y₄ independently denote hydrogen or nitro; A ⊕ denotes H⁺, Na⁺, K⁺ or NH₄⁺.
Claim 25
Dependent Claim
59 words
The magnetic toner according to Claim 23, wherein the negative charge control agent is an organic iron compound represented by the following formula: wherein X denotes capable of having a substituent, (Z ; hydrogen, halogen or nitro) (R denotes hydrogen, C₁ - C₁₈ alkyl or alkenyl) Y denotes -O- or A ⊕ denotes H⁺, Na⁺, NH₄⁺ or aliphatic ammonium.
Claim 26
Dependent Claim
111 words
The magnetic toner according to Claim 23, wherein the negative charge control agent is an N,N'-bisarylurea derivative represented by the following formula: wherein Y₁ and Y₂ independently denote phenyl, naphthyl or anthryl; R₁ and R₂ independently denote halogen, nitro, sulfonic acid, carboxyl, carboxylate, cyano, carbonyl, alkyl, alkoxy or amino; R₃ and R₃ independently denote hydrogen, alkyl, alkoxy, phenyl capable of having a substituent, aralkyl capable of having a substituent, or amino; R₅ and R₆ independently denote hydrogen or C₁ - C₈ hydrocarbon group, k and j are independently an integer of 0 - 3 with the proviso that both cannot be 0; and m and n are independently 1 or 2.
Claim 27
Dependent Claim
32 words
The magnetic toner according to Claim 1, wherein the magnetic iron oxide particles are contained in an amount of 20 - 200 wt. parts per 100 wt. parts of the binder resin.
Claim 28
Dependent Claim
48 words
A process cartridge, comprising at least a developing means and a photosensitive member; said developing means and photosensitive member being integrated into a cartridge disposed detachably attachable to an apparatus main assembly, said developing means including a magnetic toner according to any one of Claims 1 - 27.
Claim 29
Dependent Claim
47 words
An image forming method, comprising: forming an electrostatic image on an electrostatic image-bearing member, and developing the electrostatic image with a magnetic toner according to any one of Claims 1 - 27 held in a developing means to form a toner image on the electrostatic image-bearing member.
Claim 30
Dependent Claim
23 words
The image forming method according to Claim 29, wherein the toner image on the electrostatic image-bearing member is transferred to a transfer-receiving material.
Claim 31
Dependent Claim
62 words
The image forming method according to Claim 29, wherein the electrostatic image-bearing member is charged by a contact-charging means and then exposed to light to form a digital electrostatic image thereon, the digital electrostatic image is developed with the magnetic toner, and the resultant toner image on the electrostatic image-bearing member is transferred to the transfer-receiving material by a contact transfer means.
References Cited (Backward Citations)
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