Amorphous Crystalline Polyester Toner Suppresses Remelting
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Solution Overview
Problem
Conventional electrostatic charge image developing toners with crystalline polyester resin exhibit high low-temperature fixing properties, leading to remelting and image defects when used on thick papers, as the toner image softens due to latent heat and paper weight, causing attachment to other papers.
Innovation Solution
An electrostatic charge image developing toner containing a combination of amorphous and crystalline polyester resins, where the resins are compatible during the first temperature rise and separate during the second, suppressing remelting by adjusting the exothermic peak temperature range to prevent image defects on thick papers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrostatic charge image developing toners with crystalline polyester resin are used, then low-temperature fixing properties are improved, but remelting and image defects occur on thick papers
Solution Approach 1:
The patent changes the thermal parameters of the binder resin by selecting specific glass transition temperatures (Tg) and melting temperatures (Tm) for amorphous and crystalline polyester resins. The amorphous resin has Tg of 60-90°C and the crystalline resin has Tm of 40-80°C, creating a controlled temperature response that prevents remelting while maintaining low-temperature fixing capability
Solution Approach 2:
The patent uses a composite binder resin system combining amorphous polyester resin (5-40 wt%) and crystalline polyester resin (60-95 wt%). This composite structure provides both low-temperature fixing properties from the crystalline component and remelting resistance through the specific glass transition characteristics of the amorphous component
2Strength
If the toner image softens due to latent heat and paper weight, then attachment to other papers occurs, but using conventional toners prevents this attachment
Solution Approach 1:
The patent exploits phase transitions of the binder resin to control toner image behavior. The crystalline polyester resin melts at 40-80°C during fixing, providing initial adhesion, while the amorphous polyester resin's glass transition at 60-90°C prevents secondary melting under latent heat, thus preventing attachment to subsequent papers
3Reliability
If the melting and softening temperatures of the toner image are adjusted to suppress remelting, then image defects are prevented, but fixing properties may be affected
Solution Approach 1:
The patent optimizes the temperature parameters by setting the crystalline resin melting point (40-80°C) below the amorphous resin glass transition temperature (60-90°C). This parameter arrangement ensures that fixing occurs at lower temperatures while the higher glass transition temperature prevents remelting, simultaneously achieving good fixing performance and image quality
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 effectively suppresses remelting and image defects on thick papers by promoting the separation of crystalline polyester resin, maintaining the melting and softening temperatures of the toner image, thus preventing attachment and ensuring image quality.
Implementation Method 1
an endothermic peak (1) derived from a resin in which at least the amorphous polyester resin and the crystalline polyester resin are compatible is present in the first temperature rise
Implementation Method 2
at least one exothermic peak (2) is present in a temperature range which is lower than that of the endothermic peak (1) by from 5° C. to 15° C. during the second temperature rise
Implementation Method 3
the toner image softens due to latent heat and paper weight
Data Source
AI summary
An electrostatic charge image developing toner includes an amorphous polyester resin and a crystalline polyester resin as a binder resin, and by differential scanning calorimetry, which undergoes processes of a first temperature rise, cooling at a rate of −10° C./min and a second temperature rise, an endothermic peak (1) derived from a resin in which at least the amorphous polyester resin and the crystalline polyester resin are compatible is present in the first temperature rise, an exothermic peak having an intensity of 0.1 J/g or more is not present during the first temperature rise, and at least one exothermic peak (2) is present in a temperature range which is lower than that of the endothermic peak (1) by from 5° C. to 15° C. during the second temperature rise.