Toner Composition Biocide Storage Stability
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Solution Overview
Problem
Electrophotographic toner compositions, particularly those produced by the emulsion aggregation process, are prone to mold and bacteria growth due to their aqueous phase, which affects storage stability and performance under high relative humidity conditions.
Innovation Solution
Incorporating a biocide effective across a pH range of 2 to 14, such as 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, or 1,2-benzisothiazolin-3-one, into the toner composition to inhibit mold and bacteria growth, while maintaining charge stability and fusing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an aqueous phase is used in the emulsion to form toner particles with high gloss and low-melting point characteristics, then the toner achieves desired optical and melting properties, but mold and bacteria growth occurs affecting storage stability
Solution Approach 1:
A biocide is introduced as an intermediary substance into the aqueous emulsion phase to prevent mold and bacteria growth. The biocide acts as a mediator between the aqueous environment (which enables desired toner properties) and the harmful microorganisms (which threaten storage stability), allowing the system to maintain both functionality and stability simultaneously.
Solution Approach 2:
The invention modifies the chemical composition parameters of the emulsion by adding specific biocides at controlled concentrations (0.001% to 10% by weight). This parameter change transforms the emulsion from a susceptible state (prone to microbial growth) to a protected state (resistant to mold and bacteria) while preserving the aqueous phase's beneficial effects on toner gloss and melting characteristics.
2Stability of the object's composition
If a biocide is added to prevent mold and bacteria growth, then storage stability is improved, but the complexity of the composition increases
Solution Approach 1:
The biocide concentration is optimized within a specific range (0.001% to 10% by weight, preferably 5 ppm to 1000 ppm) to achieve effective protection with minimal addition. This controlled parameter change allows stability improvement while maintaining composition simplicity, as the biocide constitutes a very small fraction of the overall toner formulation.
Solution Approach 2:
The biocide functions as a sacrificial protective agent that maintains stability throughout the product's shelf life. Once its protective function is exhausted, it can be replaced, but in practice, the small required amount and long effectiveness period make it economically negligible, thus not significantly increasing composition complexity.
3Ease of operation
If the emulsion is exposed to air during storage, then the toner can be used and processed, but mold and bacteria begin to grow reducing reliability
Solution Approach 1:
The biocide is incorporated into the emulsion formulation before toner production and storage. This preliminary action establishes protective coverage in advance, so that when the emulsion is exposed to air during normal handling and storage, the biocide is already positioned to prevent microbial contamination, thereby maintaining both processability and storage reliability.
Solution Approach 2:
The biocide serves as a protective intermediary between the aqueous emulsion (which must remain accessible for processing) and atmospheric contaminants (which cause microbial growth). This intermediary allows the emulsion to maintain its functional accessibility while being protected from environmental degradation during storage and handling.
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 biocide effectively prevents mold and bacteria growth, enhances charge stability under high humidity conditions, and does not detrimentally affect other toner properties or fusing performance, thereby improving storage stability and operational efficiency.
Implementation Method 1
at least one biocide effective at a pH of from about 2 to about 14... capable of inhibiting the growth of mold, algae and/or bacteria
Data Source
AI summary
The present disclosure provides toner compositions able to prevent the formation of mold or bacterial growth during storage. In embodiments, toners may include at least one biocide that prevents the formation of mold and/or bacteria in a toner composition, including any emulsion that may be utilized in forming the toner composition. In embodiments, the biocide may also improve charging characteristics of the toner.