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US4935325A
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Toner and image forming method using magnetic material with specific tap density and linseed oil absorption
Assignee: Canon Inc
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Filing: 1988-09-06
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Granted: 1990-06-19
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Expires: 2008-09-06
Abstract
Abstract A magnetic toner suitably used for developing a digital latent image is provided. The magnetic toner comprises a binder resin and a specific magnetic material comprising spherical magnetic particles which have a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g. On the basis of the characteristics of the above-mentioned magnetic material, the magnetic toner has good image forming characteristics including image density, reproducibility of thin lines and resolution.
Inventors
- 👤 Tetsuya Kuribayashi
- 👤 Hitoshi Uchide
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:38
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0836; G03G9/0835; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
36 words
A magnetic toner, comprising a binder resin and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g.
Claim 2
Dependent Claim
36 words
A magnetic toner, comprising a binder resin and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g.
Claim 3
Dependent Claim
20 words
A magnetic toner according to claim 1, wherein the magnetic material has a linseed oil absorption of 10-25 ml/100 g.
Claim 4
Dependent Claim
20 words
A magnetic toner according to claim 1, wherein the magnetic material has a linseed oil absorption of 12-17 ml/100 g.
Claim 5
Dependent Claim
35 words
A magnetic toner according to claim 1, wherein the magnetic material comprises spherical magnetic particles which have been obtained through a disintegration treatment conducted by a pressure dispersing machine having a load-applying roller for disintegration.
Claim 6
Dependent Claim
27 words
A magnetic toner according to claim 1, wherein the magnetic material has a coercive force of 40-80 Oe as measured at a magnetic field of 10,000 Oe.
Claim 7
Dependent Claim
49 words
A magnetic toner according to claim 5, wherein the magnetic material has a saturation magnetization (σ s ) of 60-90 emu/g, a residual magnetization (σ r ) of 3-9 emu/g, and a ratio of σ r /σ s of 0.04-0.10 as measured at a magnetic field of 10,000 Oe.
Claim 8
Dependent Claim
28 words
A magnetic toner according to claim 1, wherein the magnetic material is contained in an amount of 30-150 wt. parts per 100 wt. parts of the binder resin.
Claim 9
Dependent Claim
18 words
A magnetic toner according to claim 7, wherein the binder resin comprises a styrene-acrylic acid alkyl ester copolymer.
Claim 10
Dependent Claim
17 words
A magnetic toner according to claim 7, wherein the binder resin comprises a styrenemethacrylic acid ester copolymer.
Claim 11
Dependent Claim
15 words
A magnetic toner according to claim 7, wherein the binder resin comprises a polyester resin.
Claim 12
Dependent Claim
59 words
A negatively chargeable one component-type developer, comprising a negatively chargeable magnetic toner and negatively chargeable hydrophobic silica fine powder, said magnetic toner comprising a binder resin, a negative charge controller, and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g.
Claim 13
Dependent Claim
59 words
A negatively chargeable one component-type developer, comprising a negatively chargeable magnetic toner and negatively chargeable hydrophobic silica fine powder, said magnetic toner comprising a binder resin, a negative charge controller, and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g.
Claim 14
Dependent Claim
19 words
A developer according to claim 11, wherein the magnetic material has a linseed oil absorption of 10-25 ml/100 g.
Claim 15
Dependent Claim
19 words
A developer according to claim 11, wherein the magnetic material has a linseed oil absorption of 12-17 ml/100 g.
Claim 16
Dependent Claim
34 words
A developer according to claim 11, wherein the magnetic material comprises spherical magnetic particles which have been obtained through a disintegration treatment conducted by a pressure dispersing machine having a load-applying roller for disintegration.
Claim 17
Dependent Claim
26 words
A developer according to claim 11, wherein the magnetic material has a coercive force of 40-80 Oe as measured at a magnetic field of 10,000 Oe.
Claim 18
Dependent Claim
48 words
A developer according to claim 15, wherein the magnetic material has a saturation magnetization (σ s ) of 60-90 emu/g, a residual magnetization (σ r ) of 3-9 emu/g, and a ratio of σ r /σ s of 0.04-0.10 as measured at a magnetic field of 10,000 Oe.
Claim 19
Dependent Claim
27 words
A developer according to claim 11, wherein the magnetic material is contained in an amount of 30-150 wt. parts per 100 wt. parts of the binder resin.
Claim 20
Dependent Claim
17 words
A developer according to claim 17, wherein the binder resin comprises a styrene-acrylic acid alkyl ester copolymer.
Claim 21
Dependent Claim
16 words
A developer according to claim 17, wherein the binder resin comprises a styrene-methacrylic acid ester copolymer.
Claim 22
Dependent Claim
14 words
A developer according to claim 17, wherein the binder resin comprises a polyester resin.
Claim 23
Dependent Claim
28 words
A developer according to claim 11, wherein the negative charge controller is contained in an amount of 0.1-0.9 wt. part per 100 wt. parts of the binder resin.
Claim 24
Dependent Claim
28 words
A developer according to claim 11, wherein the silica fine powder is contained in an amount of 0.3-1.0 wt. part per 100 wt. parts of the magnetic toner.
Claim 25
Dependent Claim
114 words
An image forming method, comprising: forming a digital latent image on the surface of a latent image-bearing member, forming a layer of developer comprising a magnetic toner on a developer-carrying member, said magnetic toner comprising a binder resin and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g, triboelectrically charging the magnetic toner, and transferring the magnetic toner having triboelectric charge from the developer-carrying member to the latent image-bearing member in a developing position in the presence of an alternating or a pulse electric field to form a toner image on the latent image-bearing member.
Claim 26
Dependent Claim
114 words
An image forming method, comprising: forming a digital latent image on the surface of a latent image-bearing member, forming a layer of developer comprising a magnetic toner on a developer-carrying member, said magnetic toner comprising a binder resin and a magnetic material comprising spherical magnetic particles, wherein the magnetic material has a tap density of 1.2-2.5 g/cm 3 and a linseed oil absorption of 5-30 ml/100 g, triboelectrically charging the magnetic toner, and transferring the magnetic toner having triboelectric charge from the developer-carrying member to the latent image-bearing member in a developing position in the presence of an alternating or a pulse electric field to form a toner image on the latent image-bearing member.
Claim 27
Dependent Claim
32 words
A method according to claim 23, wherein the alternating electric field is based on an AC bias component having a frequency of 200-4000 Hz and a peak-to-peak value (Vpp) of 500-3000 V.
Claim 28
Dependent Claim
27 words
A method according to claim 23, wherein a negative digital latent image is formed on the latent image-bearing member, and the magnetic toner has negative triboelectric charge.
Claim 29
Dependent Claim
21 words
An image forming method according to claim 23, wherein the magnetic material has a linseed oil absorption of 10-25 ml/100 g.
Claim 30
Dependent Claim
21 words
An image forming method according to claim 26, wherein the magnetic material has a linseed oil absorption of 12-17 ml/100 g.
Claim 31
Dependent Claim
36 words
An image forming method according to claim 23, wherein the magnetic material comprises spherical magnetic particles which have been obtained through a disintegration treatment conducted by a pressure dispersing machine having a load-applying roller for disintegration.
Claim 32
Dependent Claim
28 words
An image forming method according to claim 23, wherein the magnetic material has a coercive force of 40-80 Oe as measured at a magnetic field of 10,000 Oe.
Claim 33
Dependent Claim
50 words
An image forming method according to claim 29, wherein the magnetic material has a saturation magnetization (σ s ) of 60-90 emu/g, a residual magnetization (σ r ) of 3-9 emu/g, and a ratio of σ r /σ s of 0.04-0.10 as measured at a magnetic field of 10,000 Oe.
Claim 34
Dependent Claim
29 words
An image forming method according to claim 23, wherein the magnetic material is contained in an amount of 30-150 wt. parts per 100 wt. parts of the binder resin.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-06-18 | 1993-12-18 | 1994-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-18 | 1997-12-18 | 1998-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-18 | 2001-12-18 | 2002-06-19 | $7700.00 | Window Closed / Lapsed |