Emulsion Aggregation Toner for Low Pile Height
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional toners used in electrophotographic digital printing result in high pile heights when printed on thin flexible packaging substrates, leading to wavy rolls that are unusable for subsequent flexible packaging operations, necessitating the development of smaller size emulsion aggregation (EA) toners for low melt applications.
Innovation Solution
The process involves forming toners with a core/shell configuration using an emulsion comprising amorphous and crystalline polyester resins, an optional wax, and a photoinitiator, with particle sizes optimized between 2 to 4 microns, and a solids content of 10% to 50% by weight, using aggregating agents like aluminum sulfate to achieve low melt properties suitable for flexible packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional toners are used in electrophotographic digital printing, then surface coverage is achieved, but pile height becomes excessively high (12-14 microns) causing wavy rolls on thin flexible packaging substrates
Solution Approach 1:
The patent applies parameter changes by reducing toner particle size from conventional 8 microns to 3-4 microns, and controlling pile height to 1-6 microns through optimized emulsion aggregation processes. This size reduction directly addresses the wavy roll problem while maintaining surface coverage through controlled aggregation and coalescence mechanisms.
Solution Approach 2:
The toner composition is segmented into core and shell components with distinct functions. The core provides structural integrity while the shell controls surface properties and melting behavior. This segmentation allows independent optimization of particle size, melt characteristics, and surface coverage to achieve low pile height without sacrificing print quality.
2Adaptability or versatility
If small size emulsion aggregation toners (3-4 microns) are used to reduce pile height, then flexibility for packaging applications is improved, but manufacturing complexity increases due to optimized particle size control and aggregating agent selection
Solution Approach 1:
The patent employs preliminary action by pre-forming emulsion particles with controlled size distribution (50-200 nm) and predetermined composition before the aggregation step. The aggregating agents (aluminum salts) are pre-selected and pre-dosed to achieve target particle sizes. This preliminary preparation simplifies the overall manufacturing process by reducing the complexity of real-time particle size control during aggregation.
Solution Approach 2:
The manufacturing process utilizes parameter changes by systematically varying emulsion solids content (10-50%), particle size (50-200 nm), and aggregating agent concentration to achieve the desired final toner particle size (3-4 microns). This controlled parameter optimization enables reproducible manufacturing of small particle toners with consistent properties suitable for flexible packaging applications.
3Length of stationary object
If toner particles are aggregated to 2-3 microns using aluminum sulfate and related agents, then low pile height and low melt properties are achieved, but process optimization requirements increase for particle size and solids content
Solution Approach 1:
The patent systematically optimizes multiple parameters including emulsion particle size (50-200 nm), solids content (10-50%), and aggregating agent concentration to achieve the target particle size (2-3 microns). By establishing clear parameter ranges and their interrelationships, the patent provides a structured approach to process optimization that reduces manufacturing complexity while achieving consistent low pile height results.
Solution Approach 2:
The aggregating agents (aluminum sulfate, polyaluminum chloride, and related compounds) serve as intermediaries that mediate the aggregation process. These agents control particle-particle interactions to achieve uniform aggregation at the desired size range. By using these intermediary substances, the process becomes more controllable and easier to optimize compared to direct mechanical aggregation methods.
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 resulting toners exhibit low pile heights, high temperature document offset properties, resistance to organic solvents, and narrow size distributions, enabling non-contact fusing and improved flexibility in packaging applications.
Implementation Method 1
contacting the emulsion with from 0.1 parts per hundred to 2 parts per hundred of an aggregating agent selected from the group consisting of aluminum sulfate, polyaluminum chloride, polyaluminum bromide, polyaluminum fluoride, polyaluminum iodide, polyaluminum silicate, polyaluminum sulfosilicate, aluminum chloride, aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, and combinations thereof to form aggregated particles
Implementation Method 2
contacting the aggregated particles with at least one unsaturated polymeric resin, wherein the polymeric resin comprises a crystalline polyester having a number average molecular weight of from 1,000 to 50,000, a weight average molecular weight of from 2,000 to 100,000, and a molecular weight distribution (Mw/Mn) of from 2 to 6, in combination with a photoinitiator to form a shell over the aggregated particles
Implementation Method 3
coalescing the aggregated particles to form toner particles
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2~3
AI summary
Processes for producing emulsion aggregation toners are provided. In embodiments, methods of the present disclosure may be utilized to produce toners suitable for low melt applications, including use in flexible packaging applications, where low pile height is desired for low cost and flexibility. In embodiments, the EA toners may be prepared by optimizing the particle size of the emulsion, the choice of and amount of aggregating agent utilized, and the solids content of the emulsion.