Electrostatic Toner with Crystalline Polyester Resin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic image developing toners face challenges in achieving a balance between low-temperature fixing properties and low glossiness, leading to excessive glossiness and glare, especially when printing on coated papers at higher speeds.
Innovation Solution
The use of a binder resin comprising an amorphous vinyl resin and a crystalline polyester resin, with specific molecular weight ranges and melting point specifications, to create a toner that melts and dissolves at lower temperatures, reducing viscosity and maintaining elasticity, thereby reducing glossiness while maintaining low-temperature fixing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin and an amorphous resin are mixed to lower fixing temperature, then low-temperature fixing property is improved, but image glossiness increases excessively causing glare
Solution Approach 1:
The patent changes the molecular weight parameters of the binder resin components. Specifically, it uses a crystalline polyester resin with weight-average molecular weight of 5,000-20,000 and an amorphous resin with weight-average molecular weight of 50,000-200,000. This parameter optimization allows the resin to melt at lower temperatures while maintaining higher viscosity during fixation, preventing excessive glossiness and glare.
Solution Approach 2:
The patent creates a composite binder resin system combining crystalline polyester resin and amorphous resin in specific proportions (crystalline polyester resin: 30-70 wt%, amorphous resin: 30-70 wt%). This composite structure enables the toner to achieve both low-temperature fixing capability and controlled glossiness by leveraging the complementary properties of the two resin types.
2Productivity
If crystalline polyester resin melts during fixation to reduce viscosity, then fixing temperature is lowered, but glossiness increases and character images become less readable
Solution Approach 1:
The patent optimizes the molecular weight parameters to achieve the right balance between melting behavior and viscosity maintenance. The crystalline polyester resin with weight-average molecular weight of 5,000-20,000 melts at appropriate temperatures to enable fixing, while the amorphous resin with weight-average molecular weight of 50,000-200,000 maintains sufficient viscosity to prevent excessive glossiness and preserve character image readability.
Solution Approach 2:
The patent creates different functional zones within the binder resin system. The crystalline polyester resin component provides localized melting behavior for temperature reduction, while the amorphous resin component maintains localized viscosity for gloss control. This spatial-functional differentiation within the composite resin system resolves the contradiction between fixing temperature and image readability.
3Illumination intensity
If high-softening-point vinyl resin is used to suppress glossiness increase, then glossiness is stabilized, but low-temperature fixing property is insufficient
Solution Approach 1:
The patent changes from using high-softening-point vinyl resin to using amorphous resin with specifically controlled weight-average molecular weight of 50,000-200,000. This parameter change enables the resin to provide glossiness stability through its amorphous structure and controlled molecular weight, while simultaneously maintaining low-temperature fixing capability through its melting behavior.
Solution Approach 2:
The patent creates a composite binder resin system where crystalline polyester resin (30-70 wt%) provides melting for low-temperature fixing, and amorphous resin (30-70 wt%) provides viscosity control for glossiness stability. This composite approach successfully combines both functions without requiring high-softening-point vinyl resin, achieving both low-temperature fixing and glossiness 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 solution effectively achieves low-gloss images with improved low-temperature fixing capabilities, enhancing image quality and stability over time, even on coated papers, without causing defects like white streaks.
Implementation Method 1
the crystalline moiety melts when the toner is heated during fixing above the melting point of the crystalline polyester resin
Implementation Method 2
the crystalline polyester resin and the amorphous resin become dissolved to each other
Implementation Method 3
when kept at high temperatures during fixation under heating
Implementation Method 4
the matrix reduces the viscosity only slowly, the glossiness may therefore be suppressed from excessive increase
Data Source
AI summary
Provided is an electrostatic image developing toner comprising a toner base particle containing a binder resin and a releasing agent, wherein the binder resin comprises an amorphous vinyl resin and a crystalline polyester resin; a weight-average molecular weight of the electrostatic image developing toner is in the range of 50000 to 90000, when calculated from a chromatogram which represents a molecular weight distribution and is measured by gel permeation chromatography; a ratio of content of a resin component having a molecular weight of 100000 or more is in the range of 10 to 20% by area, in the chromatogram which represents the molecular weight distribution; the crystalline polyester resin has a melting point in the range of 65 to 85° C.; and, a ratio of content of the crystalline polyester resin in the binder resin is in the range of 5 to 20% by mass.