Polyester Toner Composition for Low-Temperature Fixing Stability
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Solution Overview
Problem
Existing toners face challenges in achieving both low-temperature fixability and storage stability, with crystalline polyester resins used for low-temperature fixability often leading to filming and reduced toner chargeability, and amorphous resins compromising storage stability.
Innovation Solution
A toner composition comprising a binder resin with a crystalline polyester and an amorphous polyester, where partial miscibility is achieved by controlling the heat treatment during production, ensuring a specific endothermic amount and glass transition temperature relationship, allowing for rapid viscosity decrease during fixing while maintaining storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is used to improve low-temperature fixability, then the fixability at low temperature is improved, but filming occurs and toner chargeability is reduced
Solution Approach 1:
The patent uses a composite binder resin system combining crystalline polyester (30-70 mass%) and amorphous polyester (30-70 mass%). The crystalline polyester provides low-temperature fixability through its melting behavior, while the amorphous polyester maintains storage stability and prevents excessive filming. This composite approach resolves the contradiction by distributing functions across different material phases.
Solution Approach 2:
The patent controls the glass transition temperature (Tg) of the amorphous polyester within a specific range (80°C to 120°C) and regulates the endothermic peak temperature of the crystalline polyester (50°C to 90°C). By optimizing these thermal parameters and their relationship, the invention achieves both low-temperature fixability and maintained chargeability after filming occurs.
2Stability of the object's composition
If an amorphous resin is used to improve storage stability, then storage stability is improved, but low-temperature fixability is compromised
Solution Approach 1:
The binder resin combines amorphous polyester (30-70 mass%) for storage stability with crystalline polyester (30-70 mass%) for low-temperature fixability. The amorphous phase provides structural stability during storage, while the crystalline phase melts at low temperatures to enable fixing, thus resolving the contradiction between storage stability and fixability.
Solution Approach 2:
The patent specifies the glass transition temperature (Tg) of the amorphous polyester within 80°C to 120°C to ensure storage stability, while simultaneously controlling the crystalline polyester's endothermic peak temperature (50°C to 90°C) for low-temperature fixability. This dual parameter control resolves the contradiction by optimizing both thermal properties within defined ranges.
3Temperature
If the crystalline polyester content is increased to improve low-temperature fixability, then low-temperature fixability is improved, but storage stability deteriorates
Solution Approach 1:
The patent defines a specific ratio range between crystalline polyester (30-70 mass%) and amorphous polyester (30-70 mass%), and controls the endothermic peak temperature (50°C to 90°C) and glass transition temperature (80°C to 120°C). This parameter optimization ensures sufficient crystalline content for low-temperature melting while maintaining enough amorphous content for storage stability.
Solution Approach 2:
The composite binder resin system balances crystalline polyester for fixability and amorphous polyester for storage stability within specific proportion ranges. This composite structure resolves the contradiction by ensuring neither component dominates excessively, maintaining both low-temperature melting capability and storage stability.
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 exhibits excellent low-temperature fixability, storage stability, and good offset resistance, enabling high-quality image formation over an extended period without compromising toner chargeability.
Implementation Method 1
a first heterogeneous structure in which a crystalline polyester and an amorphous polyester are phase-separated from each other in a radial direction of the toner base particle
Implementation Method 2
controlling the heat treatment during production
Data Source
AI summary
A toner includes: a crystalline polyester, an amorphous polyester, and a release agent. In measurement through DSC of the toner before a predetermined storage treatment, one or more peaks as an endothermic component are present in a temperature region lower than a peak derived from the crystalline polyester. The toner satisfies expression (1) below.1.5≤H1−H2≤4.5[J/g]In the expression (1), H1 is a total endothermic amount of an endothermic amount of the peak derived from the crystalline polyester and the one or more peaks present in the lower temperature region in the measurement through DSC of the toner before the storage treatment. H2 is an endothermic amount of a peak derived from the crystalline polyester in measurement through DSC of the toner after the storage treatment.