Electrophotographic Toner with Composite Resin for Offset Resistance
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Solution Overview
Problem
High-speed electrophotographic color image forming methods face challenges with toners that exhibit low melt viscosity, leading to uneven image glossiness and high temperature offset issues due to reduced energy consumption and fixing temperature, which existing solutions have not adequately addressed.
Innovation Solution
An electrophotographic toner with a specific ratio of storage modulus at different temperatures, combined with a high elastic resin and appropriate monomer composition, ensures low temperature fixability and resistance to high temperature offset, achieved through the coexistence of a resin with high elastic modulus and a toner-constituent resin of low melt viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the melt viscosity of a toner is lowered to enable low temperature fixing, then the fixing temperature can be reduced, but the toner viscoelasticity changes greatly near the fixing temperature, causing uneven image glossiness and high temperature offset
Solution Approach 1:
The patent uses a composite resin system consisting of a low melt viscosity resin (for low temperature fixing) combined with a high elastic modulus resin (for maintaining viscoelasticity). This composite approach allows the toner to achieve both low temperature fixability and resistance to high temperature offset, resolving the contradiction between fixing temperature reduction and image quality maintenance.
Solution Approach 2:
The patent carefully controls the glass transition temperature (Tg) and molecular weight of the resin components to achieve optimal viscoelasticity. By adjusting these parameters, the toner maintains appropriate storage modulus values across the fixing temperature range, preventing both uneven glossiness and offset while enabling low temperature fixing.
2Loss of energy
If the melt viscosity of a toner is lowered to save energy, then energy consumption in the fixing device is reduced, but internal cohesive forces of the melted toner become low, causing offsetting to occur easily
Solution Approach 1:
The patent combines a low melt viscosity resin with a high elastic modulus resin to create a composite toner system. The low viscosity component enables energy-efficient low temperature fixing, while the high elastic modulus component provides the necessary internal cohesive force to prevent offsetting, thus resolving the contradiction between energy savings and toner strength.
Solution Approach 2:
The patent creates different functional regions within the toner particles by controlling the distribution and properties of different resin components. The low viscosity resin provides fluidity for easy fixing with reduced energy, while the high elastic modulus resin provides localized strength where needed to prevent offsetting, achieving both energy efficiency and sufficient toner strength.
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 provides superior glossiness and resistance to high temperature offset while maintaining low temperature fixability, enhancing the performance of electrophotographic image forming processes.
Implementation Method 1
it is necessary to allow a toner to melt at a low fixing temperature
Implementation Method 2
lowering the melt viscosity of a toner by designation of a low glass transition temperature
Implementation Method 3
a toner exhibiting such a low melt viscosity greatly changes in toner viscoelasticity at a temperature neat a fixing temperature
Implementation Method 4
a ratio of a storage modulus at 60° C. to a storage modulus at 80° C., G′(60)/G′(80), is from 1×102 to 1×104
Data Source
AI summary
An electrophotographic toner is disclosed, meeting the requirement that a ratio of a storage modulus at 60° C. [G′(60)] to a storage modulus at 80° C. [G′(80)], G′(60)/G′(80) is from 1×102 to 1×104; a ratio of a storage modulus at 100° C. [G′(100)] to a storage modulus at 120° C. [G′(120)], G′(100)/G′(120) is from 1 to 10; and a storage modulus at a temperature of from 140 to 160° C., [G′(140-160)] is not less than 102 dyn/cm2.