Crystalline Resin Toner for Low-Temperature Fixability
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Solution Overview
Problem
Toner development faces challenges in achieving a balance between low-temperature fixability and heat-resistant storage stability, particularly under high-temperature and high-humidity environments, where existing toners either fail to maintain fluidity or suffer from hot offset issues due to poor adaptability on various recording media.
Innovation Solution
A toner composition comprising mother toner particles with a crystalline structure formed by resin A dispersed in resin B, where resin A has a specific length ratio and DSC endothermic quantity, along with the inclusion of ethyl acetate, to enhance low-temperature fixability and fluidity control, while maintaining heat-resistant storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the softening characteristics of toner are lowered to improve low-temperature fixability, then the fixable temperature is reduced, but the heat-resistant storage stability deteriorates
Solution Approach 1:
The patent changes the molecular structure parameters of the binder resin by introducing specific functional groups (carboxyl, hydroxyl, or amine groups) with controlled content ratios. This allows the toner to achieve low-temperature fixability through hydrogen bonding mechanisms while maintaining heat-resistant storage stability through controlled molecular weight and functional group density, resolving the contradiction between softening characteristics and storage stability.
Solution Approach 2:
The patent creates a composite binder resin system combining base resin with functional group-containing modifiers. This composite structure enables the toner to exhibit both low-temperature melting behavior (for fixability) and high-temperature structural integrity (for storage stability), effectively resolving the contradiction between opposite temperature requirements.
2Reliability
If the toner is designed to spread by heat on rough paper surfaces to prevent cold offset, then low-temperature fixability is improved, but the toner may melt and adhere to fixing members causing hot offset
Solution Approach 1:
The patent precisely controls the molecular weight distribution and functional group content of the binder resin to create a narrow melting range. This allows the toner to spread effectively on rough surfaces at low temperatures through controlled softening, while the constrained melting range prevents excessive melting that would cause hot offset on fixing members.
Solution Approach 2:
The patent creates local quality differences through functional group distribution, where hydrogen bonding sites are strategically positioned to enhance adhesion to paper surfaces while the overall molecular structure maintains thermal stability. This localized functional enhancement allows spreadability on rough surfaces without compromising hot offset resistance.
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 fluidity even under harsh conditions, preventing hot offset and ensuring high reliability and adaptability on diverse recording media, while maintaining adequate heat-resistant storage stability.
Implementation Method 1
a resin A capable of forming a crystalline structure, and a resin B incapable of forming a crystalline structure, wherein the resin A is dispersed in the resin B in the state of phase separation
Implementation Method 2
the resin A is dispersed in the resin B in the state of phase separation
Implementation Method 3
the DSC endothermic quantity attributable to the resin A is from 8 to 20 J/g
Data Source
AI summary
A toner comprised of mother toner particles each including a colorant, a resin A capable of forming a crystalline structure, and a resin B incapable of forming a crystalline structure is provided. The resin A is dispersed in the resin B in the state of phase separation. The long axis of each dispersed particle of the resin A has a length of from 30 to 200 nm and the length ratio of the long axis to the short axis is from 2 to 15. The DSC endothermic quantity attributable to the resin A is from 8 to 20 J/g.