Toner Resin Ester Concentration Fixing Chargeability
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Solution Overview
Problem
Existing toners for electrostatic charge image development face challenges in maintaining low-temperature fixability and chargeability, particularly under high-temperature and high-humidity conditions, due to the increased degree of freedom of motion at ester bonds in crystalline polyester resins, leading to decreased developability and transferability.
Innovation Solution
A toner formulation incorporating an amorphous polyester resin with 5% or more alkenyl groups having a branched structure and a crystalline polyester resin with an ester concentration within a specific range (0.04 to 0.08), which reduces the degree of freedom of motion at ester bonds, enhancing affinity between resin components and maintaining chargeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is used as binder resin, then low-temperature fixability is improved, but chargeability decreases due to increased degree of freedom of motion at ester bonds
Solution Approach 1:
The patent uses a composite binder resin system combining crystalline polyester resin (providing low-temperature fixability) with amorphous polyester resin containing alkenyl groups (providing chargeability). This composite approach allows both contradictory requirements to be satisfied simultaneously by leveraging the complementary properties of each resin type.
Solution Approach 2:
The patent controls the ester concentration parameter of the crystalline polyester resin within a specific range (0.04 to 0.08) to optimize the balance between low-temperature fixability and chargeability. By precisely adjusting this parameter, the degree of freedom of motion at ester bonds is controlled to maintain both fixing performance and chargeability.
2Temperature
If ester concentration in crystalline polyester resin is increased, then low-temperature fixability is improved, but developability decreases due to reduced affinity between resin components
Solution Approach 1:
The patent optimizes the ester concentration parameter within a specific range (0.04 to 0.08) rather than maximizing it, to maintain appropriate affinity between resin components. This parameter optimization ensures both low-temperature fixability and acceptable developability by preventing excessive rigidity.
Solution Approach 2:
The combination of crystalline and amorphous polyester resins creates a composite system where the amorphous resin component compensates for the reduced affinity caused by high ester concentration in the crystalline resin, thereby maintaining developability while achieving low-temperature fixability.
3Reliability
If amorphous polyester resin with alkenyl groups is used, then chargeability is improved, but low-temperature fixability decreases
Solution Approach 1:
The patent employs a composite binder resin system where amorphous polyester resin containing alkenyl groups (providing chargeability) is combined with crystalline polyester resin (providing low-temperature fixability). The synergistic effect of this composite system allows both chargeability and low-temperature fixability to be achieved simultaneously.
Solution Approach 2:
Different regions of the binder resin system have different properties: the crystalline polyester resin provides the low-temperature fixability needed for the fixing process, while the amorphous polyester resin with alkenyl groups provides chargeability for the development process. This local differentiation of functional properties resolves the contradiction.
Data Source
AI summary
A toner for electrostatic charge image development, the toner includes a binder resin, the binder resin includes an amorphous polyester resin having alkenyl groups and a crystalline polyester resin, about 5% or more of the alkenyl groups have a branched structure, and the o crystalline polyester resin has an ester concentration (M) obtained by the following Equation of from about 0.04 to about 0.08:M=K/A Equationwherein, K represents the number of ester bonds in the crystalline polyester resin, and A represents the number of atoms that constitute the polymer chain of the crystalline polyester resin.