Toner External Additive Composite for Flowability and Transfer
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Solution Overview
Problem
Existing toner formulations using large-diameter silica particles face issues with flowability and contamination in high-temperature, high-humidity environments, and during durable image output, leading to image quality degradation and member contamination.
Innovation Solution
A toner formulation incorporating an organosilicon polymer fine particle with a specific particle diameter and a large-diameter silica particle, where the organosilicon polymer fine particle has a low fixing rate and the silica particle has a high fixing rate, enhancing flowability and preventing embedding, thus maintaining image quality and preventing member contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large-diameter silica particle is externally added to improve transferability, then transferability is improved, but toner flowability is reduced
Solution Approach 1:
The patent uses a composite external additive system combining large-diameter silica particles (100-300 nm) for transferability improvement with small-diameter silica particles (10-50 nm) and organic silane particles (5-30 nm) for flowability maintenance. This multi-component composite approach allows simultaneous optimization of both transferability and flowability that cannot be achieved with a single particle type.
Solution Approach 2:
The patent applies different particle sizes with specific functions to different aspects of toner performance: large-diameter particles are positioned to provide transferability, while small-diameter particles are positioned to maintain flowability and prevent aggregation. This localized functional assignment resolves the contradiction by giving each particle type its specific role.
2Ease of operation
If a large quantity of small-diameter silica particle is added to compensate for flowability drop, then flowability is improved, but electrostatic aggregation occurs causing contamination and image quality decline
Solution Approach 1:
The patent changes the particle size parameter from exclusively small-diameter to a distribution including very fine particles (10-50 nm) combined with organic silane particles (5-30 nm). This parameter optimization reduces electrostatic aggregation while maintaining flowability, as the smaller particles have lower electrostatic charge and the organic silane particles provide steric stabilization.
Solution Approach 2:
The patent introduces organic silane particles as an intermediary between small-diameter silica particles and the toner matrix. These organic particles act as spacers that prevent direct contact and electrostatic aggregation of silica particles, while still maintaining flowability benefits. The organic component mediates the interaction to prevent harmful aggregation.
3Ease of operation
If small-diameter silica particles are used to maintain flowability, then flowability is improved, but charging performance deteriorates in high-temperature, high-humidity environments
Solution Approach 1:
The patent creates a composite particle system where small-diameter silica particles (providing flowability) are combined with organic silane particles and large-diameter silica particles. This composite structure maintains flowability while the organic component and larger particles compensate for charging performance degradation in high-temperature, high-humidity environments.
Solution Approach 2:
The patent assigns different functional qualities to different particle size regions: the smallest particles (10-50 nm) handle flowability, while the organic silane particles (5-30 nm) and large-diameter particles (100-300 nm) handle charging stability in harsh environments. This local functional specialization resolves the contradiction between flowability and charging reliability.
4Productivity
If small-diameter silica particles aggregate electrostatically on the toner surface, then transferability is improved, but toner flowability declines and image problems occur
Solution Approach 1:
The patent converts the potential harm of particle aggregation into a benefit by using controlled aggregation of small-diameter silica particles with organic silane particles. The organic component allows controlled clustering that improves transferability through increased surface coverage, while preventing uncontrolled electrostatic aggregation that would harm flowability. The harmful aggregation mechanism is transformed into a controlled, beneficial structure.
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 transferability and flowability while preventing member contamination, even during prolonged image output, by using an organosilicon polymer fine particle with a low fixing rate and a large-diameter silica particle with a high fixing rate, ensuring consistent image quality and reduced contamination.
Implementation Method 1
various problems caused by electrostatic aggregation of the large quantity of externally added small-diameter silica particles
Implementation Method 2
a fixing rate of the organosilicon polymer fine particle to the toner particle according to a water washing method is less than 30%, and a fixing rate of the silica fine particle to the toner particle according to the washing method is at least 30%
Data Source
AI summary
Provided is a toner including a toner particle containing a binder resin, and an external additive, wherein the external additive contains an external additive A and an external additive B, the external additive A is an organosilicon polymer fine particle, the number-average particle diameter of primary particles of the organosilicon polymer fine particle is from 30 to 300 nm, the external additive B is a silica fine particle, the number-average particle diameter of primary particles of the silica fine particle is from 100 to 300 nm, the fixing rate of the external additive A to the toner particle according to a water washing method is less than 30%, and the fixing rate of the external additive B to the toner particle according to the washing method is at least 30%.