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Toner for electronic photograph

A technology of toner and toner particles, applied in the field of toner, can solve the problems of reducing image density, increasing toner charge, reducing developing efficiency, etc.

Inactive Publication Date: 2004-09-29
HEWLETT PACKARD DEV CO LP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the amount of toner charge increases during the formation of a thin toner layer on the developing roller, the developing efficiency decreases rapidly, thereby reducing the image density
Also, when the charge amount of the toner is adjusted to a low level to prevent a decrease in developing efficiency, there is a possibility of increased image blur formation and contamination caused by toner scattering

Method used

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  • Toner for electronic photograph
  • Toner for electronic photograph
  • Toner for electronic photograph

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0069] Composition of Toner Particles

[0070] binder resin

[0071] Polyester: 92wt%

[0072] Acid value: 7mgKOH / g

[0073] Colorant (carbon black)

[0074] MA100 (Mitsubishi Chemical Co., Ltd.): 5 wt% charge control agent (iron complex)

[0075] T77 (Hodogaya Chemical Co., Ltd.): 1 wt% release agent (low molecular weight polypropylene wax)

[0076] 660P (Sanyo Chemical Industries Ltd.): 2wt%

[0077] According to a known toner preparation method, the toner particles with a particle size of 8 μm are prepared using the above-mentioned ingredients, and then the following external additives are added, thereby obtaining the toner of the present invention:

[0078] Large silica particles (NAX50, Nippon Aerosol Co., Ltd.)

[0079] Average particle size 30nm

[0080] Content 1wt%

[0081] Small silica particles (R972, Nippon Aerosol Co., Ltd.)

[0082] Average particle size 16nm

[0083] Content 0.6wt%

[0084] Conductive titanium dioxide particles (ET-500W, Ishihara Sang...

Embodiment 2

[0093] A toner of the present invention was prepared in the same manner as in Example 1 except that the electropositive alumina particles described below were used instead of the conductive titania particles.

[0094] Positively charged alumina particles (ET-500W, lshihara Sangyo Kaisha, Co.)

[0095] Average particle size 1.0μm

[0096] Content 1wt%

[0097] Charge +300μC / g

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Abstract

A toner having toner particles containing a binder resin and a colorant; and a first external additive having 0.1 to 3.0 wt% of large silica particles with an average particle size of 20 to 200 nm; a second external additive having 0.1 to 3.0 wt% of small silica particles with an average particle size of 5 to 20 nm; a third external additive having 0.1 to 2.0 wt% of hydrophobic titanium dioxide microparticles with a resistance of 10 5 to 10 12 CR .; and a fourth external additive having at least one of 0.1 to 2.0 wt% of conductive titanium dioxide particles with a resistance of 1 to 10 5 CR . and 0.1 to 2.0 wt% of positively chargeable aluminium oxide particles. Therefore, a thin toner layer with a uniform toner amount is formed on a toner carrier and stable charge distribution and toner flowability are maintained for a long time, thereby resulting in prevention of fog and toner scattering, and improvements in developing efficiency and toner durability.

Description

[0001] Cross-reference to related applications [0002] This application claims priority to Korean Patent Applications 2003-11341 and 2003-11340 filed in the Korean Intellectual Property Office on February 24, 2003, the disclosures of which are hereby incorporated by reference in their entirety. Background of the invention [0003] field of invention [0004] The present invention relates to a toner for electrophotography, and more particularly to a toner for electrophotography with improved developing efficiency, in which two kinds of silica particles different in particle size, hydrophobic titanium dioxide fine particles and conductive titanium dioxide / positive charge ( positively chargeable) alumina particles were used as external additives. [0005] Related technical description [0006] As developing methods used in electrophotography, there are two-component developing methods and one-component developing methods. The one-component developing method ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G03G9/08G03G9/097
CPCG03G9/09716G03G9/09725G03G9/08G03G9/097G03G9/09708
Inventor 李德熙殷钟文
Owner HEWLETT PACKARD DEV CO LP