Toner Binder Resin Charge Stability
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Solution Overview
Problem
Toner formulations using crystalline vinyl resins face challenges with slow charge rising and image density changes, particularly in low-humidity environments, due to instability in high-temperature, high-humidity conditions.
Innovation Solution
A toner composition featuring a binder resin with specific molar ratios and solubility parameter (SP) values of monomer units, combined with surface-treated inorganic fine particles, to enhance charge transfer and maintain low-temperature fixability and heat-resistant storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crystalline vinyl resins are used as binder resin to achieve low-temperature fixability and heat-resistant storage stability, then fixability and storage stability are improved, but charge rising speed becomes slow
Solution Approach 1:
The patent modifies the chemical composition parameters of the binder resin by incorporating specific monomer units (carboxyl-containing vinyl monomers at 5-30 mol%, hydroxyl-containing vinyl monomers at 5-30 mol%) into the crystalline vinyl resin structure. These compositional changes enable the resin to maintain crystallinity for low-temperature fixing while introducing functional groups that accelerate charge rising speed through enhanced electrostatic interaction.
Solution Approach 2:
The patent creates a composite binder resin system combining crystalline vinyl resin with specific functional monomer units (carboxyl and hydroxyl groups). This composite structure integrates the low-temperature melting properties of crystalline vinyl resin with the rapid charging capabilities of polar functional groups, resolving the contradiction between fixability and charge rising speed.
2Reliability
If crystalline vinyl resins are used to improve low-temperature fixability, then fixability is improved, but image density changes gradually when printing small print percentage images after large print percentage images
Solution Approach 1:
The patent adjusts the functional group content parameters in the binder resin (carboxyl and hydroxyl groups at specific molar percentages) to optimize both fixability and charge stability. These parameter modifications ensure consistent charging performance across different printing conditions, preventing image density variations when switching between different print percentages.
Solution Approach 2:
The patent incorporates charge control agents with specific chemical groups that provide feedback mechanisms for maintaining stable charge levels on toner particles. This feedback system regulates charge distribution, ensuring consistent image density regardless of previous printing conditions or humidity variations.
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 ensures rapid charge rising and stable image density across varying print percentages, even in high-temperature, high-humidity environments, by optimizing the composition of the binder resin and inorganic fine particles.
Implementation Method 1
surface-treated inorganic fine particles, to enhance charge transfer and maintain low-temperature fixability
Implementation Method 2
achieves both low-temperature fixability and heat-resistant storage stability
Data Source
AI summary
A toner having an inorganic fine particle and a toner particle containing a binder resin, wherein the binder resin contains a polymer A having a first monomer unit derived from a first polymerizable monomer and a second monomer unit derived from a second polymerizable monomer that is different from the first polymerizable monomer, the first polymerizable monomer is selected from the (meth)acrylic acid esters each having a C18-36 alkyl group, the content of the first monomer unit in the polymer A is within a specific range, the SP value of the first monomer unit and the SP value of the second monomer unit are in a specific relationship to one another, the inorganic fine particle is surface treated with a compound having an alkyl group, and the volume resistivity of the inorganic fine particle is within a specific range.