Decolorizable Electrophotographic Toner Capsule Structure
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Solution Overview
Problem
Conventional decolorizable toners with encapsulated colorants suffer from fogging and toner scattering due to the breakage of binder resin at the interface with the colorant, leading to the generation of fine powder, which affects image quality and apparatus contamination.
Innovation Solution
The toner is treated with a stirring process using a homogenizer to apply stress equivalent to that in an image forming apparatus, reducing the ratio of particles with equivalent circle diameters between 0.6 μm and 2.5 μm to 30% or less, thereby suppressing fine powder generation and improving charging properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a colorant is incorporated in the form of a capsule with size of about several micrometers, then the colorant can be contained within the toner, but the colorant is significantly exposed on the surface of the binder resin and the toner is easily broken at the interface between the binder resin and the colorant, leading to fine powder generation
Solution Approach 1:
The colorant is encapsulated within a capsule structure that is then incorporated into the binder resin matrix. This nested structure allows the colorant to be contained within the toner while being protected by the capsule shell, preventing direct exposure on the surface and reducing breakage at the interface between binder resin and colorant.
2Ease of operation
If the toner is subjected to stress such as stirring in an image forming apparatus, then the toner can be processed and used, but the toner is easily broken at the interface between the binder resin and the colorant, generating fine powder that causes fogging and apparatus contamination
Solution Approach 1:
The colorant is pre-encapsulated in a capsule structure before being incorporated into the binder resin. This preliminary encapsulation action creates a protective shell that prevents the colorant from being exposed on the surface, thereby preventing fine powder generation during subsequent stirring and processing operations in the image forming apparatus.
3Measurement precision
If conventional measurement techniques are used to measure fine powder, then the amount of fine powder after production can be measured, but the stress equivalent to that in a developing device cannot be applied, and the amount of fine powder when the toner is actually used cannot be reproduced
Solution Approach 1:
The toner is pre-treated with a homogenizer to apply stress equivalent to that in the developing device before measurement. This preliminary stress application reproduces the actual usage conditions, allowing the measurement to accurately reflect the amount of fine powder that will be generated during actual operation, thereby improving measurement reliability.
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
This approach effectively reduces fogging and toner scattering, enhancing image quality and apparatus cleanliness by stabilizing the toner structure and preventing binder resin breakage.
Implementation Method 1
The toner is treated with a stirring process using a homogenizer to apply stress equivalent to that in an image forming apparatus
Implementation Method 2
enhancing image quality and apparatus cleanliness by stabilizing the toner structure and preventing binder resin breakage
Data Source
AI summary
Disclosed is a decolorizable electrophotographic toner, including: a binder resin; and a colorant which contains at least a color developable compound and a color developing agent and is covered with an outer shell so as to have a capsule structure, wherein the number ratio of particles having an equivalent circle diameter of 0.6 μm or more and 2.5 μm or less of the toner when measured using a flow particle image analyzer after the toner is dispersed in an aqueous medium at a ratio of 0.08% by weight and the resulting dispersion is subjected to a stirring treatment in which stirring is performed at 5000 rpm for 30 minutes using a homogenizer (T-25 digital ULTRA-TURRAX (manufactured by IKA Japan K.K., provided with a shaft generator S25N-10G)) is 30% by number or less.