Toner Formulation with Silica Additives for Charge Stability
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Solution Overview
Problem
Conventional toners experience charge instability and reduced printing performance under high temperature and high humidity environments, leading to initial fog and deterioration in image quality and durability during continuous printing.
Innovation Solution
A toner formulation incorporating specific amounts of fatty acid metal salt particles and surface-treated spherical colloidal silica particles, along with fumed silica particles, to maintain charge stability and flowability, ensuring excellent initial charging speed and printing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional external additives are used in toner, then charging ability and flowability are improved, but charge stability deteriorates under high temperature and high humidity environments
Solution Approach 1:
The patent changes the chemical composition parameters of external additives by specifying precise ratios: fatty acid metal salt particles (0.01-0.5 part by weight), spherical colloidal silica particles (0.3-2.0 parts by weight), and fumed silica particles (0.1-1.0 part by weight). This parameter optimization resolves the contradiction by achieving both good charging ability and charge stability under severe environmental conditions.
Solution Approach 2:
The patent uses a composite external additive system combining three different materials: fatty acid metal salt particles, spherical colloidal silica particles, and fumed silica particles. This composite approach allows the toner to simultaneously achieve charging ability, flowability, and charge stability under high temperature and high humidity conditions.
2Ease of operation
If conventional external additives are used in toner, then flowability is improved, but printing durability deteriorates due to particle burial and release under mechanical stress
Solution Approach 1:
The patent optimizes particle size parameters and composition ratios to prevent external additive particles from being buried or released during continuous printing. The specific ranges of particle diameters and additive contents ensure stable attachment under mechanical stress while maintaining flowability.
Solution Approach 2:
The composite external additive system provides enhanced durability through synergistic effects: fatty acid metal salt particles provide charge stability, spherical colloidal silica particles provide flowability and resistance to burial, and fumed silica particles enhance adhesion. This composite structure maintains printing durability over 10,000 prints.
3Speed
If conventional external additives are used in toner, then initial charging speed is improved, but image quality deteriorates due to fog under severe usage environment
Solution Approach 1:
The patent adjusts the chemical composition parameters of external additives to achieve fast initial charging speed while preventing fog formation. The specific ratios of fatty acid metal salt particles, spherical colloidal silica particles, and fumed silica particles ensure rapid charging without compromising image quality even under high temperature and high 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 maintains stable charging ability and flowability, prevents image quality deterioration due to fog, and enhances printing durability even after a large number of prints under severe environmental conditions.
Implementation Method 1
a toner for developing electrostatic images comprising external additives, and colored resin particles
Implementation Method 2
spherical colloidal silica particles having a number average primary particle diameter of 30 to 80 nm and being surface-treated with a silane compound
Implementation Method 3
spherical colloidal silica particles having a number average primary particle diameter of 30 to 80 nm and being surface-treated with a silane compound having an alkyl group of 8 to 20 carbons
Implementation Method 4
fumed silica particles having a number average primary particle diameter of 5 to 25 nm as external additives
Data Source
AI summary
The present invention is to provide a toner for developing electrostatic images, comprising external additive A, external additive B, and colored resin particles comprising a binder resin and a colorant, wherein external additive A is fatty acid metal salt particles, and a content of the fatty acid metal salt particles is in the range from 0.01 to 0.5 part by weight with respect to 100 parts by weight of the colored resin particles, and wherein external additive B is spherical colloidal silica particles having a number average primary particle diameter of 30 to 80 nm and being surface-treated with a silane compound having an alkyl group of 8 to 20 carbons, and a content of the spherical colloidal silica particles is in the range from 0.3 to 2.0 parts by weight with respect to 100 parts by weight of the colored resin particles.