Toner Formulation with Low Pigment Concentration for High Density
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Solution Overview
Problem
Conventional toners for electrographic color image forming require high pigment concentrations to achieve sufficient image density, leading to increased costs and decreased image sharpness, while also resulting in high toner adhesion amounts that contribute to environmental issues and inadequate color reproduction ranges.
Innovation Solution
A toner formulation with a pigment concentration of 3.0% to 8.5% by mass and a volume average particle diameter of 2.0 to 6.0 μm, containing a binder resin and a pigment dispersant, which achieves a reflection density of 1.2 to 2.5 with a low toner adhesion amount of 0.25 mg/cm², reducing consumption rates and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pigment concentration is increased to achieve sufficient image density, then image density is improved, but toner cost increases and image sharpness decreases
Solution Approach 1:
The patent changes the particle size parameter of the toner to 5.1 μm or less, which fundamentally alters how pigment is distributed and utilized in the toner layer. This parameter change enables achieving sufficient image density (ID≥1.2) with reduced pigment concentration (3-11% by mass), resolving the contradiction between image density and pigment quantity.
Solution Approach 2:
The patent creates a composite toner material system consisting of binder resin, pigment, and specific additives in optimized proportions. This composite structure with controlled particle size and composition enables efficient light absorption and image density achievement without requiring high pigment concentrations, thus resolving the contradiction.
2Measurement precision
If pigment concentration is increased to achieve sufficient image density, then image density is improved, but toner cost increases
Solution Approach 1:
By changing the critical parameter of particle size to 5.1 μm or less, the patent enables cost-effective toner formulation with reduced pigment content (3-11% by mass). This parameter change fundamentally alters the cost structure while maintaining sufficient image density, resolving the contradiction between image density and manufacturing cost.
3Manufacturing precision
If toner particle size is reduced to improve image resolution, then image sharpness is improved, but image density decreases
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range (5.1 μm or less, preferably 4.0-5.1 μm) that simultaneously achieves both high image sharpness and sufficient image density. This precise parameter optimization resolves the contradiction between image sharpness and image density that plagues conventional toners.
4Object-affected harmful factors
If toner adhesion amount is reduced to decrease environmental impact, then environmental friendliness is improved, but image density decreases
Solution Approach 1:
By changing the particle size parameter to 5.1 μm or less, the patent enables achieving sufficient image density (ID≥1.2) with dramatically reduced toner adhesion amounts (0.2-0.4 mg/cm²). This parameter change resolves the contradiction between environmental friendliness and image density, allowing low-toner formulations to achieve offset-printing quality images.
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 high-quality images with reduced pigment usage, lower toner consumption, and enhanced color reproduction ranges, comparable to offset printing quality, while minimizing environmental impact and costs.
Implementation Method 1
developing the latent electrostatic image using a toner to form a visible image
Data Source
AI summary
The present invention provides a toner containing at least a binder resin and a pigment, wherein the amount of the pigment in the toner is 3.0% by mass to 8.5% by mass, the volume average particle diameter of the toner is 2.0 μm to 6.0 μm, and a monochrome image, which has been fixed on a recording medium so that the amount of the toner adhered onto the recording medium is 0.25 mg/cm2, has a reflection density of 1.2 to 2.5.