Core-Shell Toner with Bimodal Resin Shell for Fixability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic latent image developing toners face challenges in achieving both high-temperature preservability and low-temperature fixability, as well as charge stability, due to limitations in the structure and composition of their resin particles.
Innovation Solution
The toner particles are designed with a core-shell structure, where the shell layer consists of first resin particles with a higher softening point and a charge control agent, and second resin particles with a lower softening point, having specific diameter differences and mass ratios, which enhances thermal-stress resistance, low-temperature fixability, and charge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single type of resin particles is used in the shell layer, then the structure is simple, but both high-temperature preservability and low-temperature fixability cannot be achieved simultaneously
Solution Approach 1:
The shell layer is segmented into two distinct types of resin particles: first resin particles (60-100 nm) containing charge control agents for high-temperature preservability, and second resin particles (10-50 nm) with lower softening points for low-temperature fixability. This segmentation allows each particle type to fulfill specific functional requirements that cannot be met by a single resin type.
Solution Approach 2:
Different regions of the shell layer possess different properties: the first resin particles provide charge stability and thermal resistance, while the second resin particles provide low-temperature fixability. This local differentiation of properties enables the toner to exhibit both high-temperature preservability and low-temperature fixability simultaneously.
2Reliability
If first resin particles with higher softening point are used to improve thermal-stress resistance, then charge stability improves, but low-temperature fixability deteriorates
Solution Approach 1:
The shell layer is divided into first resin particles containing charge control agents for charge stability and second resin particles with lower softening points for low-temperature fixability. The mass ratio of first to second resin particles is controlled at 0.7-0.9, ensuring both functions are present in appropriate proportions.
Solution Approach 2:
The softening points of the two resin particle types are differentiated by at least 20°C, with first resin particles having higher softening points for thermal stability and second resin particles having lower softening points for low-temperature fixability. This parameter differentiation resolves the contradiction between charge stability and low-temperature fixability.
3Temperature
If second resin particles with lower softening point are increased to improve low-temperature fixability, then fixability improves, but thermal-stress resistance deteriorates
Solution Approach 1:
The mass ratio of first resin particles to the total resin particles is precisely controlled at 0.7-0.9, ensuring sufficient first resin particles for thermal-stress resistance while maintaining enough second resin particles for low-temperature fixability. The particle diameter difference between first and second resin particles is maintained at +20 to +50 nm for optimal performance.
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 ensures excellent low-temperature fixability, thermal-stress resistance, and charge stability, allowing for high-quality image formation across a wide temperature range.
Implementation Method 1
The first resin particles contain a charge control agent
Implementation Method 2
The first resin particles have a higher softening point than a softening point of the second resin particles
Data Source
AI summary
An electrostatic latent image developing toner includes toner particles each including a core and a shell layer disposed over a surface of the core. The shell layer contains first resin particles having a number average particle diameter of 60 nm to 100 nm and second resin particles having a number average particle diameter of 10 nm to 50 nm. A particle diameter difference obtained by subtracting the number average particle diameter of the second resin particles from the number average particle diameter of the first resin particles is +20 nm to +50 nm. The first resin particles contain a charge control agent. The first resin particles have a higher softening point than the second resin particles. A ratio of a mass of the first resin particles to a sum of the mass of the first resin particles and a mass of the second resin particles is 0.7 to 0.9.