Toner Fine Particle Layer Design for Charge Stability
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Solution Overview
Problem
Conventional toners face challenges in maintaining excellent charge rise performance and durability over long-term use, as metal compound fine particles tend to migrate to the developing roller, leading to contamination and reduced charging performance.
Innovation Solution
A toner with a fine particle layer containing metal compound fine particles, where the number-average particle diameter, average thickness, and standard deviation of the layer are controlled within specific ranges to prevent migration and ensure excellent flowability and durability, using a binder resin and silicon compounds to enhance charge transfer and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal compound fine particles are added to improve flowability and charge transfer, then charge rise performance is improved, but the particles migrate to the developing roller causing contamination and reduced durability
Solution Approach 1:
A resin coating layer is introduced as an intermediary between the metal compound fine particles and the toner base particle. This coating layer prevents direct contact and migration of metal particles to the developing roller while still allowing charge transfer to occur, thus resolving the contradiction between charge rise performance and durability
Solution Approach 2:
The invention uses composite material structure combining resin coating layer with metal compound fine particles on toner base particles. This composite structure allows the metal particles to provide charge transfer functionality while the resin coating prevents migration, achieving both improved productivity and reliability
2Productivity
If a thick coating layer of metal compound fine particles is applied to enhance charge transfer, then charge rise performance is improved, but particle migration to developing roller increases causing contamination
Solution Approach 1:
The invention optimizes the thickness parameter of the resin coating layer to a specific range (5-50 nm) that is sufficient to prevent metal particle migration to the developing roller while maintaining charge transfer efficiency. This parameter optimization resolves the contradiction between charge transfer efficiency and contamination prevention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The toner achieves excellent charge rise performance and durability, suppressing migration and contamination of metal compound fine particles, thereby maintaining consistent performance and extending toner cartridge yield.
Implementation Method 1
Toner is charged by the movement of charge from the charge-imparting member during contact with the charge-imparting member, e.g., the developing roller or carrier. Thus, an excellent charge rise performance will be exhibited by a toner that engages in numerous contact events with the charge-imparting member and for which the charge undergoes a smooth transfer during contact with the charge-imparting member.
Implementation Method 2
a toner that undergoes rapid charging due to friction with the member that imparts charge to the toner (the charge-imparting member)
Data Source
AI summary
A toner having a toner particle having a plurality of fine particles on the surface of a toner base particle, the toner base particle contains a binder resin, wherein a fine particle layer A constituted of a plurality of the fine particles is observed in an EDX mapping image of the constituent elements in a cross section of the toner particle as provided by EDX of the toner particle cross section observed using TEM; a fine particle B, containing a metal compound containing at least one metal element M selected from all the metal elements belonging to Groups 3 to 13, is observed in the fine particle layer A; and the number-average particle diameter D of the fine particle B, the average value H of the thickness of the fine particle layer A, and the standard deviation S on the thickness of the fine particle layer A satisfy prescribed relationships.