Ink-Jet Ink Set Using Thermoreversible Gel for Offset Resistance
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Solution Overview
Problem
The existing ink-jet image forming methods using actinic energy radiation curable inks face challenges in achieving offset resistance during storage, printing durability, gloss evenness on coated paper, and paper-feeding suitability, particularly due to issues with ink viscosity and gelation processes.
Innovation Solution
An ink-jet image forming method employing a combination of chromatic and colorless inks, where the colorless ink is heated and exposed to actinic energy radiation to form a thermoreversible gel, and the chromatic ink contains a gelling agent with a higher melting temperature, ensuring uniform dot height and improved image durability and gloss evenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If actinic energy radiation curable ink is used to prevent bleed, then ejection property is improved, but printing durability and offset resistance are insufficient
Solution Approach 1:
The patent changes the physical state parameter of the ink by introducing a gelling agent that causes phase transition from liquid to gel upon heating. This allows the ink to maintain low viscosity for ejection (liquid phase) and high viscosity for durability (gel phase), resolving the contradiction between ejection property and printing durability.
Solution Approach 2:
The patent utilizes phase transition of the gelling agent to control ink properties. The gelling agent transitions from dissolved state to gel state upon heating, enabling the ink to switch between ejection-friendly liquid state and durability-friendly gel state, thereby improving both ejection property and printing durability simultaneously.
2Manufacturing precision
If gelling agent is added to improve dot gain and glossiness, then dot gain is improved, but printing durability and paper-feeding suitability deteriorate
Solution Approach 1:
The patent optimizes the concentration and type of gelling agent to control the gelation threshold. By carefully selecting parameters such as gelling agent concentration (0.1-10 wt%) and melting temperature, the ink achieves improved dot gain and glossiness while maintaining printing durability and paper-feeding suitability through controlled phase transition.
3Ease of operation
If ink viscosity is reduced for ejection, then ejection property is improved, but bleed occurs
Solution Approach 1:
The patent makes the ink viscosity dynamic rather than static. The ink starts as low-viscosity liquid for easy ejection, then transitions to high-viscosity gel state after heating to prevent bleed. This dynamic viscosity adjustment allows the system to optimize for ejection property during deposition and for bleed prevention during storage.
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 method provides enhanced printing durability, reduced offset resistance, and improved gloss evenness on coated paper, along with better paper-feeding suitability by minimizing the difference in height between printed and non-printed areas, thus addressing the limitations of previous techniques.
Implementation Method 1
heating the colorless ink provided on the substrate
Implementation Method 2
a gelling agent with which a thermoreversible gel is formed
Implementation Method 3
exposing the colorless ink provided on the substrate, to actinic energy radiation
Implementation Method 4
a gelling agent with which a thermoreversible gel is formed
Data Source
AI summary
In the present invention, provided are an ink-jet image forming method employing actinic energy radiation curable ink-jet ink exhibiting no offset resistance during storage by superposing printed portions after printing in addition to excellent properties of printing durability, gloss evenness of coated paper and paper-feeding suitability, and an ink-jet ink set thereof. It is a feature that the ink-jet image forming method possessing the steps of providing colorless ink on a substrate, followed by heating the colorless ink provided on the substrate, and subsequently exposing the colorless ink provided on the substrate, to actinic energy radiation, wherein the colorless ink contains no colorant but an actinic energy radiation curable composition and a gelling agent with which a thermoreversible gel is formed.