Black–Magenta Polyester Toner Set Balancing Low-Temperature Fixing and Gloss
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Solution Overview
Problem
Existing electrostatic charge image developing toners experience non-uniformity of glossiness in black and magenta images when exposed to outdoor environments, despite ensuring low-temperature fixability, due to differential molecular movement of crystalline polyester resin at high temperatures.
Innovation Solution
The toner set comprises black and magenta toner particles with a binder resin containing an amorphous and a crystalline polyester resin, with a specific ratio of amorphous and a crystalline polyester resin, where the mass proportion of constitutional units derived from a phthalic acid other than terephthalic acid other than terephthalic acid other than terephthalic acid in the amorphous polyester resin is adjusted to suppress glossiness non-uniformity by enhancing the presence of crystalline polyester resin on the image surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a binder resin containing crystalline polyester resin is used to ensure low-temperature fixability, then fixability at low temperature is improved, but non-uniformity of glossiness occurs in black and magenta images when exposed to outdoor environments
Solution Approach 1:
The patent applies local quality by creating different molecular compositions in the amorphous polyester resin for black and magenta toners. Specifically, the magenta toner contains amorphous polyester resin with a higher proportion of constitutional units derived from phthalic acid other than terephthalic acid compared to the black toner. This local compositional difference causes differential molecular movement at high temperatures, with magenta toner molecules moving more to fill voids, thereby equalizing glossiness between the two colors when exposed to outdoor environments while maintaining low-temperature fixability.
2Stability of the object's composition
If the composition of amorphous polyester resin is adjusted to suppress glossiness non-uniformity, then glossiness uniformity is improved, but low-temperature fixability may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters of the amorphous polyester resin in each toner. The key parameter is the mass proportion of constitutional units derived from phthalic acid other than terephthalic acid, which is set to be higher in magenta toner than in black toner. This parameter adjustment modifies the molecular movement characteristics at high temperatures without compromising the low-temperature fixability, as the overall binder resin composition and crystalline polyester content remain optimized for low-temperature fixing.
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
This configuration reduces the difference in glossiness between black and magenta images under outdoor exposure while maintaining low-temperature fixability, thereby suppressing non-uniformity of glossiness.
Implementation Method 1
due to differential molecular movement of crystalline polyester resin at high temperatures
Data Source
AI summary
An electrostatic charge image developing toner set contains a black toner having black toner particles that contain a binder resin and a black colorant; and a magenta toner having magenta toner particles that contain a binder resin and a magenta colorant, in which the binder resin contained in the black toner particles and the magenta toner particles includes an amorphous polyester resin and a crystalline polyester resin, a content of the crystalline polyester resin with respect to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less, the amorphous polyester resin contained in the black toner particles and the magenta toner particles consists of a constitutional unit derived from a polyvalent carboxylic acid and a constitutional unit derived from a polyhydric alcohol, and a relationship between a mass proportion (% by mass) P(K) of the constitutional unit derived from a phthalic acid other than terephthalic acid with respect to the constitutional unit derived from a polyvalent carboxylic acid in the amorphous polyester resin contained in the black toner particles and a mass proportion (% by mass) P(M) of the constitutional unit derived from a phthalic acid other than terephthalic acid with respect to the constitutional unit derived from a polyvalent carboxylic acid in the amorphous polyester resin contained in the magenta toner particles satisfies the following expression (P1).10≤P(M)-P(K)≤40Expression (P1)