Toner Shell Layer Design for Heat-Resistant Preservability
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Solution Overview
Problem
Existing electrostatic latent image developing toners face challenges in achieving heat-resistant preservability and low-temperature fixability while maintaining high dot reproducibility and low fogging density, particularly due to issues with chargeability and reverse charging regions.
Innovation Solution
The development of an electrostatic latent image developing toner with toner particles comprising a core and a shell layer, where the shell layer is formed from two domains of different resins and includes silica particles with higher positive chargeability, ensuring a specific surface potential range and optimal shell coverage for improved heat resistance and fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a toner uses a charge control agent (calixarene) to adjust chargeability, then the surface potential can be controlled, but heat-resistant preservability and low-temperature fixability cannot be ensured
Solution Approach 1:
The toner particle is divided into different regions with different resin compositions. The shell layer contains a first resin domain and a second resin domain with different properties, creating local quality variations that simultaneously achieve proper surface potential and heat-resistant preservability without relying solely on charge control agents
Solution Approach 2:
The toner uses a composite structure with multiple resin types (first resin and second resin) in the shell layer, each contributing different properties. This composite material approach enables the toner to achieve both electrostatic properties and thermal stability that cannot be obtained with a single resin or charge control agent alone
2Ease of manufacture
If the toner configuration follows conventional designs, then manufacturing is simplified, but dot reproducibility and fogging density are impaired
Solution Approach 1:
The shell layer is designed with local quality variations through the presence of first resin domains and second resin domains in different proportions. This local differentiation enables precise control of toner properties for high-quality image formation while maintaining a relatively simple overall particle structure
Solution Approach 2:
The invention changes the resin composition parameters in the shell layer, specifically the ratio of first resin to second resin and the coverage ratio of these resins on the core surface. These parameter changes enable optimization of dot reproducibility and fogging density without fundamentally altering the basic 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
The toner achieves excellent heat-resistant preservability and low-temperature fixability, enabling high-quality image formation with high dot reproducibility and low fogging density by optimizing chargeability and surface potential distribution.
Implementation Method 1
Both the first resin and the silica particles have higher positive chargeability than the second resin. The toner particles each have an average value of surface potentials measured using a scanning probe microscope of at least +50 mV and no greater than +350 mV
Data Source
AI summary
An electrostatic latent image developing toner includes a plurality of toner particle each including a toner mother particle and silica particles attached to a surface of the toner mother particle. The toner mother particle includes a toner core and a shell layer. The shell layer includes a first domain substantially formed from a first resin and a second domain substantially formed from a second resin. Both the first resin and the silica particles have higher positive chargeability than the second resin. A shell coverage is at least 40% and no greater than 90%. The toner particles each have an average value of surface potentials measured using a scanning probe microscope of at least +50 mV and no greater than +350 mV and a standard deviation thereof of no greater than 120 mV.