Toner Particles with Variable Surface Softening for Fixability
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Solution Overview
Problem
Existing electrostatic charge image developing toners face challenges in achieving both low-temperature fixability and toner fluidity due to inadequate variation in softening temperatures across the toner particle surface, leading to reduced image density and charging issues during continuous high-density image output.
Innovation Solution
The toner particles are formulated with a combination of amorphous and crystalline resins, subjected to crosslinking treatments, and have a specific range of softening temperature differences (TH - TL) between 25°C to 100°C, ensuring appropriate variation in surface softening temperatures to maintain low-temperature fixability and toner fluidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toner particles use uniform resin composition, then manufacturing is simple, but softening temperature variation is insufficient leading to poor low-temperature fixability
Solution Approach 1:
The patent applies local quality by creating spatial variation in softening temperature across the toner particle surface. Specifically, the surface layer is designed with different resin composition or structure compared to the core, resulting in a softening temperature difference of 25-100°C between surface and interior regions. This allows the surface to provide low-temperature fixability while the core maintains structural integrity.
Solution Approach 2:
The patent uses composite materials by combining multiple resin types with different softening characteristics in the toner particle. The surface layer incorporates resins with lower softening temperatures while the core contains resins with higher softening temperatures, creating a composite structure that simultaneously achieves low-temperature fixability and maintains particle strength.
2Reliability
If toner particles have high softening temperature variation, then low-temperature fixability improves, but toner fluidity deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the softening temperature difference parameter within the range of 25-100°C. This optimized parameter range ensures that the surface layer softens sufficiently at low temperatures for good fixability, while the overall toner particle maintains appropriate fluidity for handling and image formation processes.
3Ease of operation
If toner particles have insufficient softening temperature variation, then toner fluidity is maintained, but image density decreases during continuous high-density output
Solution Approach 1:
The patent addresses this contradiction by implementing local quality through surface-specific resin modification. The surface layer is designed with lower softening temperature to facilitate charging and image density during continuous high-density output, while the core maintains higher softening temperature to preserve toner fluidity and prevent premature softening.
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 formulation secures low-temperature fixability and toner fluidity, maintaining image density and charging properties during continuous high-density image output, as evidenced by reduced white line width and image density retention.
Implementation Method 1
when a softening temperature is measured at 0.30 points in surface layer parts of the toner particles, a difference (TH(° C.)−TL(° C.)) between a maximum value (TH(° C.)) and a minimum value (TL(° C.)) out of the softening temperatures at the 30 points is from 25° C. to 100° C.
Data Source
AI summary
An electrostatic charge image developing toner includes toner particles containing an amorphous resin and a crystalline resin, wherein when a softening temperature is measured at 30 points in surface layer parts of the toner particles, a difference (TH(° C.)−TL(° C.)) between a maximum value (TH(° C.)) and a minimum value (TL(° C.)) out of the softening temperatures at the 30 points is from 25° C. to 100° C.