Toner Particle Size Distribution Control for Carrier Stability
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Solution Overview
Problem
In the electrophotographic process, the development of high-quality, high-speed, and reliable toner images is hindered by issues such as toner image deletion due to carrier deterioration, especially in low temperature and low humidity environments, where uneven charging and peeling of the resin coating layer lead to charge leakage and image defects.
Innovation Solution
The use of toner particles with a specific size distribution and the addition of conductive titania or alumina particles, which are attached to the toner, helps to stabilize the carrier and prevent deterioration by filling voids and releasing charges, thereby reducing image deletion and ensuring consistent image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toner particles are used without specific size distribution control, then the developing process is simple, but toner image deletion occurs due to carrier deterioration in low temperature and low humidity environments
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of toner particles, specifically setting the rate of fine particles (1.0-2.5 μm) to be 10-40% by number and the fine particle ratio (A/B) to be 0.18-0.40. This parameter optimization stabilizes the carrier and prevents charge leakage, thereby maintaining image quality consistency without requiring complex additional components.
Solution Approach 2:
The patent uses composite materials by combining toner particles with specific size distribution and conductive particles (silica, titania, or alumina) in a controlled ratio (0.01-5% by weight). This composite structure leverages the properties of both material types: the size-controlled toner particles provide stable charging characteristics while the conductive particles fill voids and release trapped charges, preventing carrier deterioration and image deletion.
2Reliability
If conductive particles are added to toner to prevent charge leakage, then carrier stability improves, but toner particle size distribution becomes more difficult to control
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges: the conductive particle content is limited to 0.01-5% by weight, and the fine particle ratio (A/B) is controlled at 0.18-0.40. Within these parameter boundaries, the conductive particles effectively fill voids and stabilize the carrier without significantly disrupting the toner particle size distribution, allowing both reliability and manufacturing precision to be maintained simultaneously.
3Stability of the object's composition
If fine particles are increased to improve charging uniformity, then charge distribution improves, but image deletion increases due to enhanced carrier deterioration
Solution Approach 1:
The patent applies parameter changes by optimizing the fine particle ratio (A/B) to fall within 0.18-0.40 and the fine particle content (A) to 10-40% by number. This optimized parameter range ensures sufficient charge distribution uniformity while preventing excessive carrier deterioration. The conductive particles in the toner composition further mitigate the harmful effects of fine particles by filling voids and releasing trapped charges, thereby maintaining image quality.
Solution Approach 2:
The patent introduces conductive particles (silica, titania, or alumina) as intermediary substances that mediate between the fine particles and the carrier. These conductive particles fill the voids created by fine particles and provide charge release pathways, preventing the fine particles from causing excessive carrier deterioration and image deletion, thus maintaining both charge uniformity and image quality.
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 proposed solution effectively reduces toner image deletion and maintains excellent image quality by stabilizing the carrier and preventing charge leakage, even in challenging environmental conditions.
Implementation Method 1
an external additive containing silica particles having a volume average particle diameter of 7 nm to 20 nm and at least one kind selected from the group consisting of titania particles and alumina particles... conductive titania or alumina particles, which are attached to the toner, helps to stabilize the carrier and prevent deterioration by filling voids and releasing charges
Data Source
AI summary
An electrostatic charge image developing toner includes toner particles having a volume average particle diameter of 3 μm to 16 μm, wherein, when the toner particles having a particle diameter of 1.0 μm to 30.0 μm are set as T1, the toner particles having a particle diameter of 1.0 μm to 2.5 μm are set as T2, a rate of T2 to the toner particles is set as A, the toner particles having a particle diameter of 1.0 μm to 5 μm is set as T3 and a rate of T3 to the toner particles is set as B, the rate of T2 occupying T1 is from 10% by number to 40% by number and a fine particle ratio C represented by A/B is from 0.18 to 0.40.