Polyester-Resin Toner Surface Layer for Low-Temperature Fixing
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Solution Overview
Problem
Existing toners require further improvement in low-temperature fixability and energy efficiency to meet the growing demand for energy-saving electrophotographic image forming apparatuses, while maintaining image quality.
Innovation Solution
A toner with a polyester resin having a softening point of 150°C or less, where the orientation state of molecular chains is controlled by unevenly distributing polar segments within 100 nm from the surface, using time-of-flight secondary ion mass spectrometry to achieve optimal adhesion and fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyester resin is used as a surface layer to improve charging performance, then charging performance is improved, but low-temperature fixability is insufficient
Solution Approach 1:
The patent applies local quality by creating a surface layer with specific polyester resin composition and structure that differs from the bulk toner particle. The surface layer contains polyester resin with controlled molecular weight, acid value, and composition to achieve both charging performance and low-temperature fixability. The resin composition is specifically designed to be present within 100 nm from the surface, creating a localized functional region that resolves the contradiction between charging performance and fixing temperature.
Solution Approach 2:
The patent changes multiple parameters of the polyester resin including molecular weight, acid value, composition ratio, and crystallinity to achieve the desired balance. By controlling the softening point to 150°C or less and adjusting the resin composition within specific ranges, the patent enables low-temperature fixability while maintaining charging performance. The parameter optimization allows the same resin to fulfill multiple functions simultaneously.
2Temperature
If the softening point is reduced to 150°C or less to improve low-temperature fixability, then fixability is improved, but adhesion control becomes difficult
Solution Approach 1:
The patent uses local quality by concentrating the polyester resin within 100 nm from the surface of the toner particle, creating a surface-enriched layer with controlled composition. This localized distribution allows precise control of adhesion properties at the critical interface between toner and paper, while the bulk particle maintains its structural integrity. The resin concentration and distribution are optimized to achieve uniform adhesion without excessive melting.
Solution Approach 2:
The patent employs composite materials by combining polyester resin with other toner components in a controlled ratio and spatial distribution. The surface layer composite structure includes polyester resin, inorganic particles, and other additives arranged to optimize both low-temperature fixability and adhesion control. The composite design allows each component to contribute its specific function while working together to resolve the contradiction.
3Temperature
If polyester resin is dispersed throughout the toner particle to improve fixability, then fixability is improved, but image uniformity deteriorates
Solution Approach 1:
The patent applies local quality by restricting the polyester resin distribution to within 100 nm from the surface of the toner particle, rather than dispersing it uniformly throughout the entire particle. This creates a surface-enriched layer that provides the necessary fixability at the critical interface with paper, while the interior of the particle remains compositionally uniform. This localized distribution prevents excessive resin migration that would cause image non-uniformity.
Solution Approach 2:
The patent uses segmentation by dividing the toner particle into distinct functional regions: a surface layer within 100 nm containing concentrated polyester resin for fixability, and an interior region with different composition for structural integrity and uniformity. This spatial segmentation allows each region to optimize its specific function without interfering with the other, resolving the contradiction between fixability and image uniformity.
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, energy savings, and improved image quality by enhancing adhesion between particles and paper, reducing scattering, and ensuring uniform image density.
Implementation Method 1
a value obtained by dividing an amount of counted ions for a structure represented by following formula (A) measured from the surface of the toner particle to a depth of 100 nm by time-of-flight secondary ion mass spectrometry
Implementation Method 2
measured from the surface of the toner particle to a depth of 100 nm by time-of-flight secondary ion mass spectrometry
Implementation Method 3
the toner has a softening point determined by a constant-load extrusion type capillary rheometer of 150° C. or less
Implementation Method 4
a cooling step of cooling the suspension treated in the treatment step at a cooling rate of 50° C./min or more
Data Source
AI summary
A toner and a method for producing the toner, wherein; the toner comprising a toner particle comprising a polyester resin, and has a softening point of 150° C. or less; the toner particle has the polyester resin within 100 nm from a surface of the toner particle, and where a value obtained by dividing an amount of counted ions for a structure represented by following formula (A) measured from the surface of the toner particle to a depth of 100 nm by TOF-SIMS by a total amount of counted ions is taken as a standard value, one or more peaks of the standard value are present within a range of 100 nm from the surface of the toner particle, and where A(dmax) denotes a standard value at a maximum peak and A(0) denotes a standard value on the toner particle surface, formula 1.15≤A(dmax)/A(0)≤5.00 is satisfied.