Luminescent Dye Inkjet Security Codes High-Speed Readability
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Solution Overview
Problem
Existing machine-readable and security code systems using luminescent pigments face challenges with reduced fluorescence intensity and reliability issues, particularly at high speeds and in variable printing backgrounds, leading to difficulties in deciphering codes on production lines.
Innovation Solution
The use of ink compositions containing luminescent dyes, organic solvents, solubilizing agents, and binder resins in continuous inkjet printers for printing security codes, which provide improved readability, durability, and reliability by emitting light that contrasts with backgrounds, allowing for high-speed verification and resistance to environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If luminescent pigments are used for machine readable applications, then water resistance and light stability are improved, but fluorescence intensity is reduced
Solution Approach 1:
The patent changes the chemical form of the luminescent material from pigment particles to dissolved dyes, fundamentally altering the physical state and solubility parameters to achieve high fluorescence intensity while maintaining durability through proper ink formulation
Solution Approach 2:
The patent creates a composite ink system combining luminescent dyes with specific solvents, resins, and additives to achieve both high fluorescence intensity and environmental resistance, resolving the contradiction between brightness and durability
2Duration of action of stationary object
If luminescent pigments are used, then durability is improved, but system reliability is reduced due to printing problems
Solution Approach 1:
The patent changes the ink formulation parameters from pigment-based to dye-based systems with specific solubility and flow characteristics optimized for continuous inkjet printing, eliminating clogging and dropout issues while maintaining durability
Solution Approach 2:
The patent uses dye molecules that dissolve uniformly in the ink vehicle, creating a homogeneous ink composition that reliably reproduces code patterns without the variability and clogging associated with pigment suspensions
3Productivity
If codes are printed at high speed, then productivity is improved, but code readability is reduced due to insufficient light emission
Solution Approach 1:
The patent increases the fluorescence quantum yield and intensity by using dissolved dye molecules instead of pigments, providing sufficient light emission even at high printing speeds where camera dwell time is minimal
Solution Approach 2:
The patent utilizes the periodic excitation of luminescence that occurs as items pass through the printing and verification system, with each item receiving brief but intense excitation light pulses that generate sufficient emitted light for rapid camera capture at high line speeds
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 luminescent dye-based inks enhance system uptime, maintain good print quality, and ensure code readability at high speeds, with marks being water-resistant and lightfast, enabling effective authentication and verification of security codes on products.
Implementation Method 1
Printed codes from luminescent inks are illuminated by an excitation light source with a given wavelength range and spontaneously emit light at a second wavelength range
Implementation Method 2
Fluorescent or phosphorescent pigmented inks are often selected for these applications based on their insolubility, water and lightfastness
Data Source
AI summary
A method of printing a security code on an article includes applying droplets of an ink composition with an ink jet printer to a surface of an article to print an encrypted code. The ink composition includes an organic solvent, a binder resin, and a luminescent dye.