Toner with Amorphous-Crystalline Polyester Gradient for Low-Temp Fixation
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Solution Overview
Problem
Toner containing crystalline polyester resin experiences filming on development rolls and photoreceptors due to poor mechanical strength, leading to image quality defects, especially in high-speed machines, and requires low-temperature fixation techniques to reduce energy consumption.
Innovation Solution
A toner formulation with a binder resin comprising both amorphous and crystalline polyester resins, where the solubility parameters of different molecular weight components are optimized to prevent crystalline resin exposure, achieved through an emulsification aggregation method that selectively fixes the crystalline resin within the amorphous resin, ensuring compatibility and reduced surface exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If crystalline polyester resin is used in toner to enable low-temperature fixation, then energy consumption is reduced, but the resin exposes to the surface causing filming on development rolls and photoreceptors
Solution Approach 1:
The patent applies local quality by creating a toner surface with different composition than the interior. The surface layer is enriched with amorphous polyester resin while the interior contains crystalline polyester resin. This gradient structure prevents crystalline resin exposure and filming on surfaces while maintaining low-temperature fixation capability in the toner core.
Solution Approach 2:
The patent uses composite materials by combining amorphous polyester resin and crystalline polyester resin in a specific configuration. The amorphous resin forms the surface layer with good adhesion properties, while the crystalline resin is embedded in the interior to provide low-temperature fixation. This composite structure resolves the contradiction between surface stability and energy efficiency.
2Productivity
If high-speed machine operation is performed, then productivity is improved, but crystalline resin filming occurs more frequently causing image quality defects
Solution Approach 1:
The patent creates a surface-enriched amorphous resin layer that remains stable under high-speed operation conditions. This local composition optimization prevents the crystalline resin from exposing to the surface even during high-speed processes, thereby maintaining image quality while enabling high productivity.
3Temperature
If crystalline polyester resin is used, then low-temperature fixation is achieved, but mechanical strength is poor leading to resin exposure
Solution Approach 1:
The patent combines amorphous polyester resin (providing mechanical strength and surface stability) with crystalline polyester resin (providing low-temperature fixation). The amorphous resin forms a strong surface matrix that prevents exposure, while the crystalline resin in the interior enables low-temperature melting and fixation.
Solution Approach 2:
The patent structures the toner with a nested configuration where the crystalline polyester resin is embedded within the amorphous polyester resin matrix. This nesting arrangement protects the weak crystalline resin from surface exposure while allowing it to function for low-temperature fixation.
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 prevents filming on development rolls and photoreceptors, maintaining image quality while enabling low-temperature fixation, thus reducing energy consumption and extending the lifespan of machine components.
Implementation Method 1
measured for an acetone-soluble fraction; SP(L) is the solubility parameter of a resin contained in an elution fraction (F) (80-100) from 80% to 100% of the elution of W1
Implementation Method 2
achieved through an emulsification aggregation method that selectively fixes the crystalline resin within the amorphous resin
Data Source
AI summary
The invention provides a toner for electrostatic image development having a binder resin containing a amorphous polyester resin and a crystalline polyester resin, and a coloring agent, and satisfying the following relationship (1):SP(L)>SP(H)>SP(C) (1)wherein SP(H) is the solubility parameter of a resin contained in an elution fraction F (0-10) from the beginning of elution of W1 until 10% of elution of W1 when W1 is the whole area of an elution curve on a gel permeation chromatograph measured for an acetone-soluble fraction; SP(L) is the solubility parameter of a resin contained in an elution fraction F (80-100) from 80% to 100% of the elution of W1; and SP(C) is the solubility parameter of the crystalline polyester resin.