Toner for electrostatic charge image development, two-component developer, and method for forming image

An electrostatic charge image and toner technology, which is applied in the direction of developer, electrography, instrument, etc., can solve the problems of increased electrostatic adhesion, easy over-charging, and reduced output image density.

Active Publication Date: 2015-07-29
KONICA MINOLTA INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] On the other hand, toners using polyester resins have very high negative chargeability compared to toners using styrene-acrylic copolymer resins, and tend to be easily overcharged especially in low-temperature and low-humidity environments.
If the amount of charge is too high, there will be the following problems: the electrostatic adhesion will increase, an excessive electric field strength will be required to develop the required amount of toner, and in addition, the transfer will not be sufficient and the toner will remain on the photoreceptor. , resulting in a lower density of the output image
[0008] However, even the toners disclosed in Japanese Patent Laid-Open No. 2010-102057 and Japanese Patent Laid-Open No. 2013-164477 cannot completely solve the above-mentioned problems.

Method used

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  • Toner for electrostatic charge image development, two-component developer, and method for forming image

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0209] (1) Coagulation and fusion process

[0210] Add 328 parts by mass of "resin microparticle dispersion [A1]" in terms of solid content and 2000 parts by mass of ion-exchanged water into a reaction vessel equipped with a stirring device, a temperature sensor, and a cooling pipe, and then add 5 mol / liter of hydrogen Aqueous sodium oxide solution, pH adjusted to 10 at 25°C.

[0211] Next, under stirring, an aqueous solution obtained by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30°C. Thereafter, after standing for 3 minutes, the temperature was raised, and the temperature of the system was raised to 80° C. over 60 minutes, and the particle growth reaction was continued at 80° C. In this state, the particle diameter of the associated particles was measured with "Coulter Multisizer 3" (manufactured by Beckman Coulter Co.), and the median diameter (D 50 ) reached 4.0 μm, poured 72 parts by mass of ...

Embodiment 2

[0220] (1) Coagulation and fusion process

[0221] Add 328 parts by mass of "resin microparticle dispersion [A1]" in terms of solid content and 2000 parts by mass of ion-exchanged water into a reaction vessel equipped with a stirring device, a temperature sensor, and a cooling pipe, and then add 5 mol / liter of hydrogen Aqueous sodium oxide solution, pH adjusted to 10 at 25 °C.

[0222] Next, under stirring, an aqueous solution obtained by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30°C. Thereafter, after standing for 3 minutes, the temperature was raised, and the temperature of the system was raised to 80° C. over 60 minutes, and the particle growth reaction was continued at 80° C. In this state, the particle diameter of the associated particles was measured with "Coulter Multisizer 3" (manufactured by Beckman Coulter Co.), and the median diameter (D 50 ) reached 6.0 μm, a solution obtained by dis...

Embodiment 3～12

[0228]

[0229] In the production of toner [2], toners [3] to [16] were obtained in the same manner except that the formulation in Table 1 was followed. Table 1 shows the free ratio of the fatty acid metal salt of the obtained toner and the number average particle diameter of the particles present in the supernatant.

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Abstract

To provide a toner for electrostatic charge image development, a two-component developer, and a method for forming an image in which a high quality image can be stably obtained by suppression of a decrease in image density as caused by excessive electrification in a low temperature and low humidity environment, prevention of fogging as caused by lowered electrification property in a high temperature and high humidity environment, and suppression of a difference in image density. A toner for electrostatic charge image development which contains toner particles containing at least a binder resin and external additives containing metal salts of fatty acid, in which a ratio of the metal salts of fatty acid that are liberated by a centrifugal treatment in an aqueous dispersion is 30 to 80% and the number average particle diameter of the particles that are present in a supernatant after the centrifugal treatment is 0.7 μm to 3.0 μm, the ratio and the number average particle diameter of the particles being measured by the centrifugation of the aqueous dispersion of the toner, and the binder resin present on a surface of the toner particles contains a vinyl polymer part and a polyester part.

Description

technical field [0001] The present invention relates to a toner for developing an electrostatic charge image (hereinafter simply referred to as "toner") used in electrophotographic image formation, a two-component developer containing the toner, and the use of the two-component developer image forming method. Background technique [0002] With the popularization of digital printing, higher image quality, energy saving and high image stability are increasingly required. [0003] In the field of toners, from the viewpoint of energy saving, the development of low-temperature fixing toners capable of fixing with less energy is progressing. In order to obtain a toner with a low fixing temperature, it is necessary to lower the melting temperature and melt viscosity of the binder resin. Compared with styrene-acrylic copolymer resins conventionally used as binder resins, polyester resins have the advantage of being easy to design with a low softening point while maintaining a high...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G03G9/087
CPCG03G9/08755G03G9/08728G03G9/0819G03G9/09791
Inventor 柴田幸治内野哲中村公亮
Owner KONICA MINOLTA INC
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