Toner Surface Protrusions for Image Quality and Transfer Efficiency
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Solution Overview
Problem
Existing electrostatic image developing dry toners face challenges with low-temperature fixability, heat-resistant storage stability, chargeability, adhesion resistance, and cleanability, particularly due to issues with particle size uniformity and glass transition temperature, leading to background smears and degradation in image quality.
Innovation Solution
A toner with protruding portions on its surface, where the average length of the long sides is between 0.1 µm and 0.5 µm, and a standard deviation of 0.2 or less, with a glass transition temperature between 45°C and 70°C, and the resin in the protruding portions having a glass transition temperature between 45°C and 100°C, ensuring uniform chargeability and adhesion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polymerization toners are used to increase sphericity and reduce particle diameter, then image definition is improved, but transfer efficiency degrades and filming occurs
Solution Approach 1:
The invention applies local quality by creating protruding portions only on the surface of toner particles rather than modifying the entire particle structure. These protruding portions (0.05-0.5 μm in size) are localized surface features that provide adhesion sites without affecting the overall spherical shape and size distribution of the toner particles, thus maintaining transfer efficiency while improving image definition.
Solution Approach 2:
The toner particle surface is segmented into protruding portions and base particle regions. This segmentation allows different functional zones: the protruding portions provide adhesion sites for transfer, while the base particle maintains the spherical shape and size characteristics needed for high-definition imaging. The protruding portions are distributed at a coverage of 10-80% of the particle surface area.
2Manufacturing precision
If toner particles are reduced in particle diameter for high-definition images, then resolution is improved, but adhesion to members increases causing filming
Solution Approach 1:
The invention creates localized protruding portions on the toner particle surface that concentrate adhesion properties in specific areas rather than distributing adhesion uniformly across the entire particle surface. This local concentration of adhesion sites allows small particles to adhere effectively to the transfer belt at contact points without excessive overall adhesion that would cause filming on other surfaces.
Solution Approach 2:
The protruding portions provide partial adhesion action concentrated at specific surface locations rather than complete surface adhesion. This partial adhesion is sufficient for transfer purposes while avoiding the excessive adhesion that would cause filming, achieving the right balance for high-definition imaging without the harmful side effects.
3Ease of operation
If surface modification is applied to improve cleanability, then cleanability is improved, but background smears increase and storage stability degrades
Solution Approach 1:
The invention applies surface modification locally by creating protruding portions rather than uniformly coating the entire particle surface. These protruding portions provide cleanability through their specific surface morphology while the base particle surface maintains its original properties, preventing background smears and maintaining storage stability. The protruding portions cover 10-80% of the particle surface area.
4Use of energy by moving object
If binder resins with low melting temperatures are used for low-temperature fixability, then energy consumption is reduced, but heat-resistant storage stability degrades
Solution Approach 1:
The invention creates local protruding portions with specific glass transition temperatures (45-100°C) on the toner particle surface. These protruding portions can be composed of resins with different thermal properties than the base particle, allowing low-temperature fixability through the protruding portions while the base particle maintains heat-resistant storage stability. This local differentiation of thermal properties resolves the contradiction between low-energy fixing and stable storage.
Data Source
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AI summary
A toner including a binder resin, a colorant and protruding portions on a surface of the toner, wherein the average length of long sides of the protruding portions is 0.1 µm or greater, but less than 0.5 µm, wherein the standard deviation of the lengths of the long sides of the protruding portions is 0.2 or less, and wherein the protruding portions have a coverage of 30% to 90%.