Ester-Bond Toner Composition for Stable Charging and Clean Images
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Solution Overview
Problem
Existing toners face a trade-off between suppressing image streaks and black spots after long-term use in high-speed, long-life electrophotographic image forming apparatuses due to the detachment and migration of external additives, leading to uneven toner charging distribution.
Innovation Solution
A toner formulation with a binder resin containing an ester bond and a specific external additive treated with a fluorine-containing silane coupling agent, where boric acid is detected near the surface, and the external additive has a charge amount of −0.5 μC/g or less, achieved through a controlled detachment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external additive is strongly treated to suppress image streaks, then charge rising performance is improved, but external additive becomes embedded causing black spots
Solution Approach 1:
The patent changes the chemical composition parameters of the binder resin by incorporating polyester resin with specific functional groups that interact with the fluorine-containing silane coupling agent on the external additive surface. This parameter change optimizes the balance between holding the external additive and preventing embedding, resolving the contradiction between charge rising performance and black spot prevention
Solution Approach 2:
The patent uses a composite binder resin system combining polyester resin with specific additives that create an optimal interface with the fluorine-containing silane coupling agent. This composite material structure allows the external additive to be held firmly for good charge rising performance while preventing excessive embedding that causes black spots
2Stability of the object's composition
If external additive is embedded to suppress detachment, then charge distribution stability is improved, but embedded portions become locally charged causing black spots
Solution Approach 1:
The patent modifies the binder resin composition parameters to include polyester resin with specific functional characteristics that control the degree of external additive embedding. This parameter optimization ensures sufficient embedding for charge distribution stability while limiting embedding depth to prevent local charging and black spots
Solution Approach 2:
The patent creates a gradient structure where the binder resin has different properties at different depths, with the surface layer optimized for holding external additives and the bulk layer optimized for preventing excessive embedding. This local quality differentiation resolves the contradiction between charge distribution stability and black spot prevention
3Productivity
If processing speed is increased, then productivity is improved, but external additive migrates causing broader charging distribution
Solution Approach 1:
The patent applies fluorine-containing silane coupling agent treatment to the external additive surface before incorporation into the toner, creating a pre-formed stable interface that prevents migration during high-speed processing. This preliminary action ensures the external additive remains firmly attached even under the stress of increased processing speeds
Solution Approach 2:
The patent uses a composite binder resin system specifically designed to bond with fluorine-containing silane coupling agents, creating a multi-layered structure that anchors the external additive firmly. This composite material approach prevents external additive migration during high-speed processing while maintaining narrow charging distribution
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 stabilizes charge distribution, suppressing both image streaks and black spots, ensuring high-quality images over extended service life and increased processing speeds.
Implementation Method 1
treating an external additive by using a combination of a fluorine-containing silane coupling agent and a hydrophobizing agent other than a fluorine-containing silane coupling agent
Implementation Method 2
the binder resin comprises a resin having an ester bond
Implementation Method 3
a peak corresponding to boric acid is detected in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal
Implementation Method 4
it is essential to rapidly charge a toner in order to increase the speed of a printer, and one means for achieving this is to fix an external additive having negative properties
Data Source
AI summary
A toner comprising: a toner particle comprising a binder resin; and an external additive on a surface of the toner particle, wherein the binder resin comprises a resin having an ester bond, a peak corresponding to boric acid is detected in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal, and when a dispersed solution obtained by dispersing the toner in an aqueous solution containing a surfactant is subjected to a detachment treatment A including shaking for 300 seconds using a shaker, and when an external additive detached from the toner by the detachment treatment A is denoted as external additive A, a charge amount of the external additive A using a standard carrier (F81) is −0.5 μC/g or less.