Small-Particle Developing Toner With Core-Coating Adhesion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic charge image developing toners with small particle diameters tend to adhere to fixing members during the formation of low image density images, leading to image defects such as blurring.
Innovation Solution
The toner particles are designed with a core portion containing a binder resin and a release agent with a melting temperature of 80°C or less, coated with an amorphous polyester resin layer, and have a specific configuration of release agent domains and a controlled coating layer thickness to facilitate easy adhesion to recording media and prevent adherence to fixing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the toner particle diameter is reduced to improve image resolution, then image quality is improved, but the toner tends to adhere to the fixing member during low image density printing
Solution Approach 1:
The toner particle is segmented into a core portion containing the binder resin and a release agent, and a coating layer containing amorphous polyester resin. This segmentation allows the release agent to be positioned in the core where it can effectively prevent adhesion to the fixing member while the coating layer provides the necessary surface properties for low image density printing.
Solution Approach 2:
The invention changes the melting temperature parameter of the release agent to 80°C or less, and controls the coating layer thickness ratio to 1% or more and 25% or less. These parameter changes enable the release agent to exude and spread on the fixing member at appropriate temperatures, preventing toner adhesion while maintaining image quality.
2Reliability
If the coating layer thickness is increased to improve toner stability, then toner durability is improved, but the release agent cannot effectively prevent adhesion during low image density printing
Solution Approach 1:
The invention optimizes the coating layer thickness ratio to 1% or more and 25% or less of the toner particle maximum diameter. This parameter optimization allows the coating layer to provide sufficient protection and stability while still permitting the release agent in the core to exude and prevent adhesion to the fixing member during low image density printing.
3Object-generated harmful factors
If the release agent domain size is increased to improve release effectiveness, then adhesion prevention is improved, but the toner particle structure becomes unstable
Solution Approach 1:
The invention changes the release agent domain circle-equivalent diameter parameter to 1 μm or more and 3 μm or less, and controls the number of domains to 1 or more and 3 or less per cross section. These parameter changes enable the release agent domains to be large enough to effectively prevent adhesion while maintaining a stable and uniform toner particle structure.
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
This configuration effectively prevents toner adhesion to fixing members during low image density printing, ensuring clear and defect-free images by allowing the release agent to exude and spread on the fixing member, enhancing image quality.
Implementation Method 1
a release agent that has a melting temperature Tm of 80° C. or less
Implementation Method 2
a coating layer that coats the core portion and contains an amorphous polyester resin
Data Source
AI summary
An electrostatic charge image developing toner contains: a toner particle including a core portion containing a binder resin and a release agent that has a melting temperature Tm of 80° C. or less, and a coating layer that coats the core portion and contains an amorphous polyester resin, and the toner particle has a cross section in which one or more and three or less domains of the release agent are present in the core portion, the one or more and three or less domains having a circle-equivalent diameter of 1 μm or more and 3 μm or less, the toner particle has a volume average particle diameter of 4.2 μm or more and 5.8 μm or less, and a ratio of a thickness of the coating layer to a maximum diameter of the toner particle is 1% or more and 25% or less in the cross section.