Toner Shell Polymer and Fine Silica Additive Adhesion
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Solution Overview
Problem
Existing toners face challenges in maintaining durability and preventing member contamination when using large-particle-diameter external additives, as these additives often fail to adhere properly due to weak physical/electrostatic forces on the toner particle surface, leading to image defects and contamination.
Innovation Solution
A toner with a core-shell structure, where the shell comprises a polymer with monomer units represented by Formula (I), and an external additive A with a particle diameter of 30 to 300 nm, selected from silica fine particles or organosilicon polymer fine particles, is used. The ratio of coverage of the toner particle surface with the external additive A is maintained at 0.3 area % or higher, enhancing adhesion and reducing migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large-particle-diameter external additive is used to improve durability, then durability is improved, but adhesion to the toner particle surface deteriorates due to weak physical/electrostatic forces
Solution Approach 1:
The patent changes the particle diameter parameter of the external additive from large (conventional) to fine (30-300 nm), which fundamentally alters the adhesion mechanism. Fine particles experience stronger van der Waals forces and electrostatic attraction relative to their size, enabling them to adhere firmly to the toner particle surface while still providing durability benefits.
Solution Approach 2:
The patent creates a composite structure by combining fine external additive particles with the toner particle surface. This composite approach allows the fine particles to serve dual functions: adhering strongly to the toner surface through enhanced surface forces while simultaneously providing the durability improvement sought from larger particles.
2Reliability
If a large-particle-diameter external additive is used to improve durability, then durability is improved, but member contamination increases due to poor adhesion
Solution Approach 1:
By changing the particle diameter parameter to the fine range (30-300 nm), the external additive particles achieve sufficient adhesion strength to remain attached to the toner particle surface during transfer and fixation processes. This prevents the contamination of charging members and photosensitive drums that occurs with larger, poorly-adhering particles.
Solution Approach 2:
The patent converts the potential harm of large particle size (poor adhesion) into a benefit by using fine particle size. The fine particles, which would traditionally be considered too small to provide durability, actually achieve both strong adhesion and durability improvement, thereby eliminating the contamination problem.
3Reliability
If an external additive is added to improve durability, then durability is improved, but image streaks increase due to migration of the external additive
Solution Approach 1:
The patent changes the particle diameter parameter to fine (30-300 nm), which enables the external additive particles to embed into and adhere firmly on the toner particle surface. This strong adhesion prevents particle migration during the printing process, thereby eliminating image streaks while maintaining durability improvements.
4Reliability
If the surface of the toner particle is covered with external additive to improve durability, then durability is improved, but low-temperature fixability deteriorates
Solution Approach 1:
The patent changes the particle diameter parameter to fine (30-300 nm), which allows the external additive particles to form a thin, uniform coating on the toner particle surface. This thin coating provides durability protection without creating a thick barrier that would hinder heat transfer during fixation, thereby maintaining low-temperature fixability.
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 toner effectively suppresses the migration of external additives, improves image streaks, and reduces member contamination, while ensuring low-temperature fixability, thus addressing the limitations of existing toners.
Implementation Method 1
physical/electrostatic forces onto the toner particle surface
Implementation Method 2
physical/electrostatic forces onto the toner particle surface
Implementation Method 3
L1 represents —COO(CH2)n— (where n is an integer of 1 to 10), and carbonyl of L1 is bonded to a carbon atom of a main chain; R1 represents hydrogen or a methyl group; and R2 to R10 represent each independently an alkyl group having 1 to 4 carbon atoms
Data Source
AI summary
A toner, comprising a toner particle, wherein the toner particle has a core-shell structure comprising a core particle and a shell on a surface of the core particle, the shell comprises a polymer having monomer units represented by Formula (I) below, the toner comprises a specific external additive A, the external additive A is at least one selected from the group consisting of silica fine particles and organosilicon polymer fine particles, and a ratio of coverage of a surface of the toner particle with the external additive A is 0.3 area % or higher:in Formula (I), L1 represents —COO(CH2)n— (where n is an integer of 1 to 10), and carbonyl of L1 is bonded to a carbon atom of a main chain; R1 represents hydrogen or a methyl group; and R2 to R10 represent each independently an alkyl group having 1 to 4 carbon atoms.