Toner External Additive Particle Size and Conductivity Control
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Solution Overview
Problem
Existing toners face challenges in achieving desired image density and stability during electrostatic latent image development due to issues with external additive particle size and conductivity, leading to inadequate image formation and excessive charging in low-temperature and low-humidity environments.
Innovation Solution
Incorporating specific external additive particles with a number average primary particle diameter of at least 30 nm and no greater than 305 nm, such as antimony-doped tin oxide or indium tin oxide, which have a controlled Sb or In ratio to enhance conductivity and remain stably attached to toner mother particles, thereby improving image density and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external additive particles with smaller size are used to improve image density, then image formation quality improves, but particles become easily buried in toner mother particles
Solution Approach 1:
The patent specifies a precise particle diameter range (30-305 nm) for external additive particles to optimize both image density and prevent burial. This parameter optimization ensures particles are small enough for good image formation but large enough to remain stable on toner surfaces.
Solution Approach 2:
The patent uses composite inorganic particles containing multiple metal elements (Sn, In, Sb, Zn, Al, Ti, Si, B) with specific compositional ratios. This composite structure enhances particle conductivity and stability while maintaining appropriate size for image quality.
2Reliability
If external additive particles with larger size are used to prevent burial, then particle stability improves, but image density and electrostatic responsiveness deteriorate
Solution Approach 1:
The patent establishes an upper size limit of 305 nm for external additive particles. This prevents particles from becoming too large, which would reduce image density and electrostatic responsiveness, while still maintaining sufficient stability to avoid burial during toner application.
Solution Approach 2:
The use of composite inorganic particles with specific metal element compositions enhances the electrostatic responsiveness of larger particles, allowing them to maintain good image density performance even at the upper size limit of 305 nm.
3Adaptability or versatility
If conventional external additives are used in low-temperature and low-humidity environments, then basic toner function is maintained, but excessive charging occurs and image stability deteriorates
Solution Approach 1:
The patent employs composite inorganic particles containing specific combinations of metal elements (Sn, In, Sb, Zn, Al, Ti, Si, B) with controlled compositional ratios. This composite structure provides stable electrostatic properties across different environmental conditions, preventing excessive charging in low-temperature and low-humidity environments while maintaining image stability.
Solution Approach 2:
The patent optimizes the compositional parameters of external additive particles, specifically controlling the ratios of metal elements to achieve desired conductivity and environmental stability. This parameter optimization ensures consistent performance across varying temperature and humidity conditions.
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 desired image density and stability by ensuring the external additive particles do not become buried or detached, maintaining excellent electric field responsiveness and developability, even in challenging environmental conditions.
Implementation Method 1
The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles... maintaining excellent electric field responsiveness
Data Source
AI summary
A toner includes toner particles. The toner particles each include a toner mother particle and an external additive attached to the surface of the toner mother particle. The external additive includes specific external additive particles. The specific external additive particles have a number average primary particle diameter of at least 30 nm and no greater than 305 nm. The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles. A ratio (MSb/(MSn+MSb)) of a mass (MSb) of an antimony atom to a total of the mass (MSb) of the antimony atom and a mass (MSn) of a tin atom in the antimony-doped tin oxide particles is at least 0.04 and no greater than 0.46.