Phosphorescent Toner Particle Size Optimization
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Solution Overview
Problem
Toner-based imaging techniques are vulnerable to forgery due to the ease of duplicating documents, and existing phosphorescent toners with small particle sizes result in reduced brightness and require time-consuming multi-step processes.
Innovation Solution
A toner with phosphorescent pigment particles of 15 μm to 55 μm diameter, combined with a thermoplastic resin binder, charge-controlling agent, and optional colorant, is developed using melt-blending and classification methods, eliminating the need for a master batch step, allowing for extended glow-in-the-dark images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphorescent pigment particles with small particle size (0.01 μm to 9.0 μm) are used, then the toner can be manufactured, but the brightness of the phosphorescent material is reduced
Solution Approach 1:
The patent changes the particle size parameter of phosphorescent pigment from the conventional small size (0.01-9.0 μm) to a larger size range (15-55 μm), which directly improves the brightness and glow duration of the phosphorescent image while maintaining manufacturability through modified processing parameters
2Reliability
If a multi-step process including master batch formation is used, then the toner can be manufactured with phosphorescent material, but the process requires additional time and expense
Solution Approach 1:
The patent merges the phosphorescent pigment incorporation step with the main toner manufacturing process, eliminating the separate master batch formation step. The phosphorescent pigment is added to the toner mixture during the same processing operation, reducing manufacturing time and cost while maintaining product quality
Solution Approach 2:
The patent extracts and eliminates the master batch formation step from the conventional multi-step process, directly incorporating phosphorescent pigment into the toner manufacturing process to reduce time and expense
3Illumination intensity
If phosphorescent pigment particles with large particle size (>7.0 μm) are used, then the brightness is improved, but the phosphorescent pigment tends to be separated from within the toner particle
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range (15-55 μm) that balances brightness improvement with toner particle stability. This intermediate size range prevents both excessive brightness loss (from small particles) and particle separation (from large particles), achieving a compromise that maintains both performance and uniformity
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 produces bright, long-lasting glow-in-the-dark images that are secure, easy to manufacture, and cost-effective, suitable for various applications including security and on-demand printing.
Implementation Method 1
The phosphorescent pigment glows in the dark for an extended period of time after it has been exposed to natural and/or artificial light
Data Source
AI summary
A method of making a toner composition including at least one phosphorescent pigment that absorbs energy released by natural or artificial light, and is able to be seen in a dark environment through luminescence of a certain color created by the energy released as light, is described. The phosphorescent toner has a particle size in the range of about 15 to 40 microns, which allows the toner to have the ability to absorb and then release the needed amount of light energy to be noticeable in a dark environment.