US4952476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic magnetic toner containing polyalkylene and vinyl polymer
Assignee: Canon Inc
•
Filing: 1989-02-22
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Granted: 1990-08-28
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Expires: 2009-02-22
Abstract
Abstract A magnetic toner comprising a binder resin, magnetic powder and 0.1-10 wt. % (based on resin component) of a low-molecular weight polyalkylene, the binder resin comprising a vinyl-type polymer having 5 to 80 wt. % of a tetrahydrofuran (THF)-insoluble; the magnetic toner having a melt index of 0.2 to 12 g/10 min. (125° C., 10 kg load); the residual magnetization σ r and the volume-average particle size d of the magnetic toner satisfying the following formula: 3.7-0.11d≦σ.sub.r ≦6.5-0.23d, wherein σ r represents a residual magnetization (emu/g) under an external magnetic field of 1 KOe and d represents a volume-average particle size of 3 to 16 microns.
Inventors
- 👤 Kiichiro Sakashita
- 👤 Toshiaki Nakahara
- 👤 Hirohide Tanikawa
- 👤 Satoshi Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:07
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0819; G03G9/0821; G03G9/087; G03G9/08784; G03G9/08795; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
140 words
A magnetic toner, comprising a binder resin, magnetic powder and 0.1-10 wt. % based on the resin component of a low-molecular weight polyalkylene, said binder resin comprising a vinyl-type polymer having 5 to 80 wt. % of a tetrahydrofuran-insoluble; said magnetic toner having a melt index of 0.2 to 12 g/10 min. at 125° C., and 10 kg load; the residual magnetization σ r and the volume-average particle size d of said magnetic toner satisfying the following formula: 3.7-0.11d≦σ r ≦6.5-0.23d, wherein σ r represents a residual magnetization in emu/g under an external magnetic field of 1 KOe and d represents a volume-average particle size of 3 to 16 microns; wherein the magnetic powder has an average particle size of 0.1 -1 micron and is contained in an amount of 40-200 wt. parts per 100 wt. parts of resin component.
Claim 2
Dependent Claim
140 words
A magnetic toner, comprising a binder resin, magnetic powder and 0.1-10 wt. % based on the resin component of a low-molecular weight polyalkylene, said binder resin comprising a vinyl-type polymer having 5 to 80 wt. % of a tetrahydrofuran-insoluble; said magnetic toner having a melt index of 0.2 to 12 g/10 min. at 125° C., and 10 kg load; the residual magnetization σ r and the volume-average particle size d of said magnetic toner satisfying the following formula: 3.7-0.11d≦σ r ≦6.5-0.23d, wherein σ r represents a residual magnetization in emu/g under an external magnetic field of 1 KOe and d represents a volume-average particle size of 3 to 16 microns; wherein the magnetic powder has an average particle size of 0.1 -1 micron and is contained in an amount of 40-200 wt. parts per 100 wt. parts of resin component.
Claim 3
Dependent Claim
15 words
A magnetic toner according to claim 1, wherein the binder resin comprises a vinyl-type copolymer.
Claim 4
Dependent Claim
16 words
A magnetic toner according to claim 2, wherein the binder resin comprises a crosslinked vinyl-type copolymer.
Claim 5
Dependent Claim
26 words
A magnetic toner according to claim 3, wherein the binder resin comprises a crosslinked styrene-acrylic acid ester type copolymer or a styrene-methacrylic acid ester type copolymer.
Claim 6
Dependent Claim
18 words
A magnetic toner according to claim 1, wherein the binder resin contains 10-60 wt. % of a THF-insoluble.
Claim 7
Dependent Claim
19 words
A magnetic toner according to claim 1, which has a melt index value of 0.5 to 8 g/10 min.
Claim 8
Dependent Claim
19 words
A magnetic toner according to claim 1, wherein the low-molecular weight polyalkylene has a weight-average molecular weight of 2,000-30,000.
Claim 9
Dependent Claim
27 words
A magnetic toner according to claim 1, wherein the low-molecular weight polyalkylene is contained in an amount of 0.5 to 8 wt. % based on resin component.
Claim 10
Dependent Claim
19 words
A magnetic toner according to claim 1, wherein the magnetic powder has an average particle size of 0.1-0.5 micron.
Claim 11
Dependent Claim
27 words
A magnetic toner according to claim 8, wherein the magnetic powder is contained in an amount of 50-150 wt. parts per 100 wt. parts of resin component.
Claim 12
Dependent Claim
15 words
A magnetic toner according to claim 1, wherein the binder resin contains a charge controller.
Claim 13
Dependent Claim
15 words
A magnetic toner according to claim 1, which has been mixed with silica fine powder.
Claim 14
Dependent Claim
34 words
A magnetic toner according to claim 1, which has a triboelectric chargeability so as to provide an absolute value of charge amount Q/S expressed as nc/cm 2 of 3 to 12 nc/cm 2 .
Claim 15
Dependent Claim
34 words
A magnetic toner according to claim 13, which has a triboelectric chargeability so as to provide an absolute value of charge amount Q/S expressed as nc/cm 2 of 4 to 11 nc/cm 2 .
Claim 16
Dependent Claim
34 words
A magnetic toner according to claim 14, which has a triboelectric chargeability so as to provide an absolute value of charge amount Q/S expressed as nc/cm 2 of 5 to 10 nc/cm 2 .
Claim 17
Dependent Claim
24 words
A magnetic toner according to claim 1, which contains a positive charge controller and has been mixed with positively chargeable hydrophobic silica fine powder.
Claim 18
Dependent Claim
28 words
A magnetic toner according to claim 16, wherein the charge controller comprises Nigrosine, and the silica fine powder comprises silica fine powder treated with an amino-modified silicone oil.
Claim 19
Dependent Claim
23 words
A magnetic toner according to claim 1, which contains a negative charge controller and has been mixed with negative hydrophobic silica fine powder.
Claim 20
Dependent Claim
17 words
A magnetic toner according to claim 18, wherein the magnetic charge controller comprises an organic metal complex.
Claim 21
Dependent Claim
53 words
In the process for developing electrophotographic images with a one-component magnetic toner by the steps of: (a) forming an electrostatic latent image on a photosensitive member, and (b) developing said latent image with said one-component magnetic toner, the improvement which comprises employing the magnetic toner of claim 1 as the one-component magnetic toner.
References Cited (Backward Citations)
US4137188A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |