Transparent Toner Gloss Unevenness Control via Release Agent Thermal Parameters
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Solution Overview
Problem
Conventional transparent toners experience gloss unevenness due to crystal growth of the release agent, which affects image quality and transparency, especially during double-side printing, as the crystal form of the release agent tends to become flat, leading to diffused reflection of light and reduced OHP transparency.
Innovation Solution
A transparent toner with a specific composition including a binder resin and a release agent, where the difference between the endothermic peak temperature (Tm) and exothermic peak temperature (Tc) of the release agent is maintained between 30°C to 50°C, and the weight average molecular weight is between 35,000 to 70,000, inhibiting crystal growth and maintaining a spherical shape of the release agent domains, thereby suppressing gloss unevenness and enhancing image smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transparent toners are used, then the release agent can be incorporated into the toner composition, but the release agent undergoes crystal growth and becomes flat, causing gloss unevenness and reduced OHP transparency
Solution Approach 1:
The patent changes the molecular weight parameter of the binder resin to a specific range (35,000 to 70,000) and controls the thermal parameters (Tm-Tc difference of 30-50°C) of the release agent to prevent crystal growth and maintain spherical shape, thereby resolving the gloss unevenness issue
Solution Approach 2:
The patent creates a composite toner system where the binder resin and release agent work together with specific property relationships. The binder resin with controlled molecular weight and the release agent with specific thermal characteristics form a composite structure that prevents release agent crystallization while maintaining transparency
2Ease of manufacture
If the release agent crystal form becomes flat, then the toner can be formed, but light undergoes diffused reflection causing gloss unevenness
Solution Approach 1:
By controlling the molecular weight of the binder resin (35,000-70,000) and the thermal parameters of the release agent (Tm-Tc difference of 30-50°C), the patent maintains the release agent in a spherical non-crystalline state, preventing diffused reflection and gloss unevenness while allowing proper toner formation
3Strength
If the molecular weight of the binder resin is increased, then the toner strength improves, but the release agent is more prone to crystal growth
Solution Approach 1:
The patent identifies and controls two critical parameters: the molecular weight of the binder resin (35,000-70,000) and the thermal parameter difference (Tm-Tc of 30-50°C) of the release agent. This dual parameter control allows achieving both high toner strength and prevention of release agent crystal growth simultaneously
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 solution effectively suppresses gloss unevenness and maintains high transparency by preventing crystal growth of the release agent, ensuring improved image quality and scratch resistance, even at high molecular weights, without compromising OHP transparency.
Implementation Method 1
the difference between Tm and Tc being from about 30° C. to about 50° C., wherein Tm is an endothermic peak temperature of the release agent determined in a temperature rising process and Tc is an exothermic peak temperature of the release agent determined in a temperature decreasing process
Implementation Method 2
the crystal growth of the release agent, which affects image quality and transparency
Data Source
AI summary
A transparent toner for electrostatic latent image developing, including a binder resin and a release agent, the difference between Tm and Tc being from about 30° C. to about 50° C., wherein Tm is an endothermic peak temperature of the release agent determined in a temperature rising process and Tc is an exothermic peak temperature of the release agent determined in a temperature decreasing process, in a measurement by a differential scanning calorimeter (DSC) according an ASTM method, and the toner having a weight average molecular weight of from about 35,000 to about 70,000.