Toner Production pH Control to Suppress Aluminum Hydroxide Gel
Solution Overview
Problem
Existing methods for producing toners for electrostatic charge images face issues with color spots and fogging due to the formation of gel-like substances, particularly aluminum hydroxide, which are difficult to remove and affect image quality.
Innovation Solution
A method involving the aggregation of resin particles using an aluminum aggregating agent, followed by heating and fusing, cooling, and adjusting the pH of the toner particle dispersion to between 8 and 11 to prevent gel-like substance formation and maintain chargeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an aluminum aggregating agent is used to aggregate resin particles, then aggregation efficiency is improved, but gel-like substances (aluminum hydroxide) are formed causing color spots and fogging
Solution Approach 1:
The patent extracts and removes the harmful aluminum hydroxide gel-like substances from the system through washing steps. The toner particles are washed with water to remove aluminum hydroxide formed during aggregation, thereby eliminating the cause of color spots and fogging while maintaining the benefits of aluminum-based aggregation
Solution Approach 2:
The patent introduces an intermediary washing step between aggregation and toner formation. This washing step acts as a mediator that removes harmful aluminum hydroxide while preserving the aggregated toner particle structure, allowing the use of aluminum aggregating agents without their harmful side effects
2Object-generated harmful factors
If pH is adjusted to less than 8 to remove aluminum hydroxide, then color spots are suppressed, but chargeability deteriorates
Solution Approach 1:
The patent performs preliminary removal of aluminum hydroxide through washing before pH adjustment is needed. By removing aluminum hydroxide in advance through washing steps, the patent avoids the need to adjust pH to less than 8, thereby maintaining chargeability while still suppressing color spots
Solution Approach 2:
The patent cushions against the potential problem of color spots by preemptively removing aluminum hydroxide through washing. This prior removal prevents the formation of color spots without requiring extreme pH adjustment that would harm chargeability, thus cushioning against both problems simultaneously
3Object-generated harmful factors
If washing is performed to remove aluminum hydroxide, then image quality is improved, but production complexity increases
Solution Approach 1:
The patent merges the washing step with existing process stages. The washing is integrated into the toner production flow, combining particle separation, washing, and drying into a unified process rather than adding completely separate equipment, thereby reducing overall complexity while still removing aluminum hydroxide effectively
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 suppresses the occurrence of color spots and fogging in the final image by preventing the formation of aluminum hydroxide and maintaining optimal charge properties.
Implementation Method 1
an aggregation step of aggregating at least resin particles contained in a dispersion by using an aluminum aggregating agent to form aggregated particles
Implementation Method 2
a fusing step of heating and fusing the aggregated particles to form fused particles
Implementation Method 3
a cooling step of cooling a dispersion containing the fused particles to obtain a toner particle dispersion
Data Source
AI summary
A method for producing a toner for developing an electrostatic charge image includes: aggregating at least resin particles contained in a dispersion by using an aluminum aggregating agent to form aggregated particles; heating and fusing the aggregated particles to form fused particles; cooling a dispersion containing the fused particles to obtain a toner particle dispersion; and adjusting a pH of the toner particle dispersion to 8 or more and 11 or less.