Clear Overcoat Composition Stabilizing Phase Change Ink Viscosity
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Solution Overview
Problem
Current protective coatings for ink and toner-based images in imaging devices, particularly those using phase change ink, face challenges with ink rub and offset during handling, requiring improved thermal and light stability, scratch resistance, and reduced viscosity to prevent smearing and clogging.
Innovation Solution
A clear or substantially clear overcoat composition comprising specific waxes, such as hydroxyl-terminated polyethylene wax, and a thermal stabilizer like 4,4′-Bis(α,α-dimethylbenzyl)diphenylamine, optionally with resins, which can be used in solid ink formulations to prevent smearing and offsetting of images, maintaining low viscosity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective coating is applied to prevent ink rub and offset, then image protection is improved, but the coating viscosity increases over time causing clogging
Solution Approach 1:
A stabilizer is added to the overcoat composition before printing to prevent viscosity increase during storage and handling. This preliminary stabilization prevents the harmful effect of viscosity increase over time, allowing the protective coating to maintain its low viscosity and flow properties throughout the printing process and subsequent handling.
Solution Approach 2:
The stabilizer acts as an intermediary substance that mediates between the overcoat composition and environmental factors (heat, light, oxygen) that would otherwise cause viscosity increase. The stabilizer absorbs or neutralizes these harmful effects, protecting the overcoat's rheological properties while maintaining its protective function.
2Stability of the object's composition
If the overcoat composition provides thermal stability, then resistance to smearing is improved, but the complexity of the composition increases
Solution Approach 1:
The patent extracts and addresses only the critical stability issue by adding a specific stabilizer component to the overcoat composition. Rather than redesigning the entire composition, the solution focuses on adding a single functional ingredient that provides thermal stability and prevents smearing, thereby minimizing the increase in composition complexity while achieving the desired performance improvement.
3Ease of operation
If the overcoat maintains low viscosity for extended handling, then ease of operation is improved, but protection against offset deteriorates
Solution Approach 1:
The stabilizer enables the overcoat composition to maintain its viscosity parameter within an optimal range over extended periods. By preventing viscosity increase, the stabilizer ensures the overcoat remains easy to handle and apply while simultaneously maintaining its protective properties against offset, as the low viscosity allows for uniform coating that adheres properly without excessive rubbing or offsetting.
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 overcoat composition effectively reduces smearing and offsetting of ink and toner-based images, maintaining high image quality even under harsh conditions, such as extended handling, and is compatible with existing printing systems, ensuring robust prints with low coefficient of friction for automatic document feeding systems.
Implementation Method 1
4,4′-Bis(α,α-dimethylbenzyl)diphenylamine; a stabilizer
Implementation Method 2
A phase change ink jet printer employes phase change inks that are in the solid phase at ambient temperature, but transition to a liquid phase at an elevated temperature
Implementation Method 3
Once the ejected ink is on the image receiving substrate, the ink droplets quickly solidify to form an image
Data Source
AI summary
Present embodiments generally relate to a novel clear or colorless overcoat composition that may be used for overcoating, for example, ink based images and xerographic images. The overcoat composition, which may be used as a base for a clear solid ink, comprises one or more waxes. Also included in the present embodiments is methods for using and stabilizing the overcoat composition as a solid ink.