Toner External Additive with Urethane Bonds for Fixing and Transfer
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Solution Overview
Problem
Existing toners face challenges in simultaneously achieving high low-temperature fixability and transferability, especially when the speed of image forming devices increases, as they often require trade-offs between these properties.
Innovation Solution
A toner composition with an external additive containing crystalline resin or wax particles, each having urethane or urea bonds, with melting points between 50°C to 130°C, which enhances adhesion to paper and improves transferability while maintaining low-temperature fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional toners are used to improve low-temperature fixability, then transferability deteriorates
Solution Approach 1:
The invention uses composite particles consisting of inorganic fine particles (such as silica, alumina, or titania) embedded within or coated on crystalline resin fine particles. This composite structure combines the low melting point and polarity of crystalline resin with the adhesion properties of inorganic particles, enabling both low-temperature fixability and high transferability to be achieved simultaneously.
Solution Approach 2:
The invention specifies precise parameter ranges: the crystalline resin has a melting point of 50°C to 130°C and the inorganic fine particles have a particle diameter of 10 nm to 500 nm. By controlling these parameters, the toner achieves optimal low-temperature fixability while maintaining high transferability, resolving the contradiction between these two properties.
2Productivity
If image forming device speed is increased, then transferability deteriorates
Solution Approach 1:
The invention applies external additives to toner particles in advance before the imaging process. These additives (composite particles of crystalline resin and inorganic fine particles) pre-establish the necessary adhesion properties on the toner surface, ensuring that even at high speeds, the toner maintains sufficient adhesion to paper for complete transfer.
Solution Approach 2:
The composite structure of crystalline resin with embedded or coated inorganic fine particles provides both the melting characteristics needed for low-temperature processing and the surface properties needed for high-speed transfer, allowing the system to maintain reliability at increased speeds.
3Temperature
If crystalline resin fine particles are added to improve low-temperature fixability, then image density deteriorates
Solution Approach 1:
The invention creates composite particles where inorganic fine particles are embedded within or coated on crystalline resin fine particles. This composite structure maintains the low melting point of crystalline resin for low-temperature fixability while the inorganic particles provide sufficient adhesion to paper, preventing toner detachment and preserving image density.
Solution Approach 2:
The inorganic fine particles are specifically positioned on the surface or within the crystalline resin particles, creating local regions of high polarity and adhesion. This local enhancement of adhesion properties allows the toner to maintain both low-temperature fixability and image density without compromise.
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 achieves excellent low-temperature fixability and transferability even at increased image forming device speeds, ensuring effective toner adhesion and transfer without degrading durability, by utilizing the high polarity of urethane or urea bonds in the crystalline resin or wax particles.
Implementation Method 1
enhances adhesion to paper and improves transferability
Implementation Method 2
the melting point of the crystalline resin and the melting point of the wax are each from 50° C. to 130° C.
Implementation Method 3
by utilizing the high polarity of urethane or urea bonds in the crystalline resin or wax particles
Data Source
AI summary
A toner includes toner particles and an external additive; the external additive includes an external additive A containing fine particles of a crystalline resin or fine particles of a wax; the crystalline resin and the wax each have an urethane bond or an urea bond; and the melting point of the crystalline resin and the melting point of the wax are each from 50° C. to 130° C.