Method for manufacturing yellow toner for electrostatic charge image development

A multi-stage process for manufacturing yellow toner with specific organic pigments and inorganic fine particles addresses the stability and uniformity issues, enhancing durability under low temperature and low humidity conditions.

JP2025102135AActive Publication Date: 2025-07-08KAO CORP
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Patent Information

Application Number
JP2023219391
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Filing Date
2023-12-26
Publication Date
2025-07-08
Estimated Expiration
2043-12-26

AI Technical Summary

Technical Problem

Yellow toner in full-color printing exhibits lower coloring power and stability due to aggregation of pigments, leading to uneven distribution and reduced fluidity, especially under low temperature and low humidity conditions, resulting in non-uniform layer thickness and increased fogging.

Method used

A method involving melt-kneading a binder resin and colorant, followed by multiple stages of pulverization and mixing with inorganic fine particles, using an organic yellow pigment with a specific NH group amount, to enhance adhesion and dispersion, ensuring durability under low temperature and low humidity.

Benefits of technology

The method produces a yellow toner with improved durability and stability, reducing smudging and maintaining uniformity under challenging environmental conditions.

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Abstract

To provide a method for manufacturing a yellow toner for electrostatic charge image development which is excellent in durability under low temperature and low humidity.SOLUTION: A method for manufacturing a yellow toner for electrostatic charge image development includes a step 1 of melting and kneading at least a binder resin and a coloring agent using an open roll type kneader, a step 2 of pulverizing the kneaded material obtained in the step 1, and then mixing the obtained pulverized material with inorganic fine particles, and a step 3 of pulverizing the mixed material obtained in the step 2, and classifying the pulverized material, wherein when a value obtained by dividing the total number of -NH-groups and -NH2 groups in one molecule by the molecular amount is an NH group amount, the coloring agent contains an organic yellow pigment having an NH group amount of 2.7 mmol / g or more, and the content of the organic yellow pigment is 6 pts.mass or more and 20 pts.mass or less with respect to 100 pts.mass of the binder resin.SELECTED DRAWING: None
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Citation Information

Patent Citations

  • Manufacture of color toner

    JP1999202551A

  • Electrostatic charge image developing toner

    JP2006227431A

  • Method for manufacturing toner

    JP2007225707A

  • Toner for electrostatic charge image development

    JP2019174672A

  • Toner binder resin

    JP2020063412A