Composite Toner Resin for Low-Temperature Fixing and Hot Offset Resistance
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Solution Overview
Problem
Current toners for electrophotography face challenges in achieving balanced low-temperature fixing property, hot offset resistance, and heat resistance storageability, with existing solutions either compromising on image quality or energy efficiency.
Innovation Solution
A toner formulation comprising a crystalline polyester resin, a non-crystalline resin, and a composite resin with specific molecular weight distribution and thermal properties, along with an inorganic compound, to enhance dispersion and thermal stability, ensuring effective low-temperature fixing and hot offset resistance while maintaining heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature (Tg) of binder resin is lowered to improve low-temperature fixing property, then fixing performance at lower temperatures is improved, but heat resistance storageability deteriorates
Solution Approach 1:
The patent uses a composite binder resin system comprising polyester resin (providing low-temperature fixing performance) and styrene-acryl resin (providing heat resistance storageability). This composite approach allows each resin component to contribute its advantageous properties, resolving the contradiction between low-temperature fixing and heat resistance storageability.
Solution Approach 2:
The patent optimizes the glass transition temperature (Tg) of the polyester resin to a specific range (80°C to 120°C) and controls the ratio of polyester resin to styrene-acryl resin within defined parameters. By precisely controlling these parameters, the toner achieves both low-temperature fixing performance and heat resistance storageability simultaneously.
2Temperature
If the softening temperature (T1/2) of binder resin is lowered to improve low-temperature fixing property, then fixing performance is improved, but hot offset resistance deteriorates
Solution Approach 1:
The patent combines polyester resin with low softening temperature (for low-temperature fixing) with styrene-acryl resin having high softening temperature (for hot offset resistance). The composite resin system allows the toner to fix at low temperatures while resisting hot offset through the high-temperature-performance component.
Solution Approach 2:
Different regions of the toner particle have different resin compositions: the polyester resin provides low-temperature fixing capability while the styrene-acryl resin provides hot offset resistance. This local differentiation of resin functions within the toner particle resolves the contradiction between low-temperature fixing and hot offset resistance.
3Reliability
If fixing temperature is increased to avoid fixing failures in rapid systems, then image quality is maintained, but energy consumption increases and fixing device heat leakage increases
Solution Approach 1:
The patent changes the thermal parameters of the toner itself by selecting polyester resin with specific Tg (80°C to 120°C) and T1/2 values, enabling the toner to fix at lower temperatures. This parameter change in the toner composition eliminates the need to increase fixing temperature, thereby reducing energy consumption and heat leakage while maintaining fixing performance.
Solution Approach 2:
The patent develops a toner formulation that is self-optimizing for low-temperature fixing, eliminating the need for high-energy fixing processes. The toner's molecular structure is designed to facilitate fixing at low temperatures, making the system more energy-efficient without sacrificing image quality.
4Temperature
If crystalline polyester resin is used to improve low-temperature fixing property, then fixing performance is improved, but dispersion diameter increases causing transfer failures
Solution Approach 1:
The patent combines crystalline polyester resin (providing low-temperature fixing) with styrene-acryl resin (providing good dispersion characteristics). The styrene-acryl resin acts as a dispersant, preventing the crystalline polyester resin from forming large aggregates, thus maintaining small dispersion diameter while preserving low-temperature fixing performance.
Solution Approach 2:
The styrene-acryl resin serves as an intermediary substance between the crystalline polyester resin and the toner matrix. It facilitates uniform dispersion of the crystalline polyester resin throughout the toner particle, preventing aggregation and ensuring proper transfer characteristics while maintaining the low-temperature fixing benefits of the crystalline polyester.
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 satisfactory low-temperature fixing property, hot offset resistance, and heat resistance storageability, ensuring high-quality image formation over a long period with improved transferability and reduced energy consumption.
Implementation Method 1
a resin having a lowered Tg causes degradation of heat resistance storageability
Implementation Method 2
a prefixed toner image on a recording medium typified by paper is fixed on the recording medium by heat and pressure
Implementation Method 3
an inorganic compound, to enhance dispersion and thermal stability
Implementation Method 4
heat resistance storageability
Data Source
AI summary
A toner, including: a binder resin; and a colorant, wherein the binder resin contains: a crystalline polyester resin (A); a non-crystalline resin (B); and a composite resin (C), where the composite resin (C) contains a condensation polymerization resin unit and an addition polymerization resin unit, wherein the toner contains chloroform insoluble matter in an amount of 1% by mass to 30% by mass, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000 and a half width of 15,000 or less, where the molecular weight distribution is obtained through gel permeation chromatography (GPC) of tetrahydrofuran soluble matter of the toner, and wherein the toner has an endothermic peak in a range of 90° C. to 130° C. in measurement through differential scanning calorimetry (DSC).