Toner Production via pH-Controlled Non-Crystalline Resin Attachment
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Solution Overview
Problem
Existing electrostatic charge image development toners experience gloss unevenness when forming high-image-density images after being stored for a period in high-temperature and high-humidity environments, due to the formation of white beads which are not properly developed.
Innovation Solution
A method involving the aggregation of polyester resin particles and a flat color material, followed by the attachment of non-crystalline resin particles, and subsequent heating to coalesce the particles, where the non-crystalline resin particle dispersion's pH, particle diameter, and acid value are controlled within specific ranges to reduce the formation of white beads and thus gloss unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If toner is stored in high-temperature and high-humidity environment for a period, then storage stability is improved, but gloss unevenness occurs due to white bead formation
Solution Approach 1:
The patent applies preliminary action by controlling the pH of the non-crystalline resin particle dispersion to be within a specific range (3.0-6.5) before the toner is stored in high-temperature and high-humidity environment. This preliminary pH control prevents white bead formation during storage, thereby maintaining both storage stability and gloss uniformity without requiring any additional action during the storage period.
2Stability of the object's composition
If non-crystalline resin particles are added to aggregate particles, then binder resin coverage is improved, but particle aggregation control becomes difficult
Solution Approach 1:
The patent applies parameter changes by controlling the pH of the non-crystalline resin particle dispersion within a specific range (3.0-6.5). This pH parameter control enables the non-crystalline resin particles to be properly attached to the aggregate particles, achieving uniform binder resin coverage while maintaining simple aggregation control. The specific pH range ensures optimal particle interaction without requiring complex control mechanisms.
3Manufacturing precision
If pH of non-crystalline resin dispersion is controlled within specific range, then white bead formation is reduced, but dispersion stability becomes sensitive to pH variations
Solution Approach 1:
The patent applies parameter changes by establishing a specific pH range (3.0-6.5) for the non-crystalline resin particle dispersion. By controlling the pH within this range, the patent achieves reduced white bead formation while maintaining dispersion stability. The specific pH range provides optimal conditions for particle stability and prevents aggregation, balancing white bead reduction with dispersion stability.
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 method effectively reduces gloss unevenness by ensuring the non-crystalline resin particles are properly attached and dispersed, preventing the formation of white beads and enhancing image quality under varying environmental conditions.
Implementation Method 1
adding a non-crystalline resin particle dispersion in which non-crystalline resin particles are dispersed to the first aggregated particle dispersion to cause the non-crystalline resin particles to be attached to the first aggregated particles
Implementation Method 2
heating a second aggregated particle dispersion in which the second aggregated particles are dispersed to cause the second aggregated particles to coalesce
Data Source
AI summary
A method for producing an electrostatic charge image development toner includes: a first step of aggregating polyester resin particles and a flat color material to produce a first aggregated particle dispersion in which first aggregated particles having a number-average particle diameter of 1 μm or more are dispersed; a second step of adding a non-crystalline resin particle dispersion in which non-crystalline resin particles are dispersed to the first aggregated particle dispersion to cause the non-crystalline resin particles to be attached to the first aggregated particles and obtain second aggregated particles; and a third step of heating a second aggregated particle dispersion in which the second aggregated particles are dispersed to cause the second aggregated particles to coalesce, wherein the non-crystalline resin particle dispersion satisfies Formulas (1) to (3), Formula (1): −0.01×A−0.25×B+9.2≤pH≤−0.01×A−0.25×B+10.0, Formula (2): 100 nm≤A≤250 nm, Formula (3): 5 mgKOH/g≤B≤20 mgKOH/g, in which A is a particle diameter of the non-crystalline resin particles, B is an acid value of the non-crystalline resin, and pH is a pH of the non-crystalline resin particle dispersion.