Toner Composition Balancing Low-Temperature Fixing and Blooming Control
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Solution Overview
Problem
Existing toners face challenges in achieving both low-temperature fixability and image heat resistance, particularly when exposed to high temperature and high humidity environments, leading to blooming and charge leakage issues.
Innovation Solution
A toner composition comprising a binder resin with specific ratios of amorphous and crystalline polyesters, surface coverage by silica fine particles, and controlled wax distribution to enhance crystallization and prevent blooming, ensuring excellent charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crystalline polyester is easily crystallized to achieve excellent low-temperature fixability and image heat resistance, then the crystallization during cooling is facilitated, but when left under high temperature and high humidity environment for long time, blooming occurs and charge leakage ensues
Solution Approach 1:
A shell layer comprising a specific resin and silane-modified polyester is formed around the toner particle to act as a barrier between the crystalline polyester core and the external environment. This shell prevents blooming of the crystalline polyester surface while maintaining the crystallization benefits for low-temperature fixability and image heat resistance.
Solution Approach 2:
The toner particle is constructed as a composite structure with a core-shell configuration. The core contains crystalline polyester for heat resistance, while the shell contains silane-modified polyester and specific resin to prevent blooming. This composite structure integrates multiple functions that would be contradictory in a single material.
2Temperature
If the crystalline polyester content is increased to improve image heat resistance, then the crystallization peak appears in XRD spectrum, but blooming occurs more severely under high temperature and high humidity conditions
Solution Approach 1:
The silane-modified polyester shell acts as an intermediary layer that allows the crystalline polyester core to maintain its crystallization structure for heat resistance while preventing direct exposure to environmental moisture and heat that would cause blooming and charge leakage.
Solution Approach 2:
The patent modifies the chemical parameters of the polyester by using silane-modified polyester in the shell layer, which changes the surface properties and interaction with the environment, thereby preventing blooming while preserving the crystallization-induced heat resistance properties of the core.
3Temperature
If the toner is designed for excellent low-temperature fixability, then the binder resin facilitates crystallization during cooling, but the toner becomes sensitive to high temperature and high humidity environments
Solution Approach 1:
The toner particle is segmented into functional zones: a core region containing crystalline polyester for low-temperature fixability and a shell region containing silane-modified polyester and resin for environmental stability. This segmentation allows each region to optimize its specific function without compromising the other.
Solution Approach 2:
The shell layer serves as an intermediary protective barrier that isolates the crystalline polyester core from adverse environmental conditions, thereby maintaining charging performance stability while preserving the low-temperature fixability provided by the crystalline core.
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 low-temperature fixability and image heat resistance, maintaining effective charging performance even under high temperature and humidity conditions.
Implementation Method 1
the crystalline portion and the amorphous portion in the crystalline polyester are controlled to facilitate crystallization during cooling
Implementation Method 2
a toner that can be fixed at a lower temperature and has excellent low-temperature fixability
Implementation Method 3
silica fine particle on a surface of the toner particle
Data Source
AI summary
A toner including a toner particle containing a binder resin containing an amorphous polyester A and a crystalline polyester C, and a wax, and a silica fine particle, wherein the content of the crystalline polyester C is within a specific range, the softening point of the amorphous polyester A satisfies a specific relationship, and in an X-ray diffraction spectrum under a specific temperature condition for the toner, there is a peak corresponding to the crystalline polyester C, a wax index AW1 and a crystalline polyester index AC1 of the toner satisfy a specific relationship, the silica fine particle contains a silica fine particle A having a maximum diameter of primary particle in a specific range, and the average coverages of the surface of the toner before and after the toner is treated with hexane with the silica fine particle A satisfy a specific relationship.