Inkjet Ink Offset Suppression via Penetrating Agents
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Solution Overview
Problem
Inkjet recording apparatuses face challenges in achieving high-speed image formation while preventing ink offset and maintaining desired image density, particularly in line head-type systems, where ink penetrability and drying issues lead to image defects and contamination.
Innovation Solution
A water-based ink formulation containing a pigment dispersion with a specific resin molecular weight, glycerin, 1,3-propanediol as humectants, 1,2-octanediol as a high penetrating agent, and C2-C4 monoalkyl ethers of polyhydric alcohols, optimized to balance penetrability and image density, and including a dissolution stabilizer to prevent ink thickening and recovery issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the amount of ink ejected is decreased to suppress offset, then offset is suppressed, but image density becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by adding specific penetrating agents (2-ethyl-1,3-hexanediol at 1-5 mass%) and controlling the resin molecular weight (35,000-140,000), which fundamentally alters how the ink interacts with the recording medium, enabling rapid penetration that prevents offset while maintaining image density
Solution Approach 2:
The patent creates a composite ink formulation combining water, pigment dispersion, resin, penetrating agents (2-ethyl-1,3-hexanediol and C2-C4 monoalkyl ethers), and humectants in specific proportions, where each component contributes to achieving both rapid penetration and sufficient image density
2Speed
If the content of 2-ethyl-1,3-hexanediol is increased to improve penetrability, then penetrability is improved, but coloring agent penetrates inside the recording medium causing reduced image density
Solution Approach 1:
The patent precisely controls the concentration parameter of 2-ethyl-1,3-hexanediol at 1-5 mass% and pairs it with resin having specific molecular weight (35,000-140,000), optimizing the penetration speed to be sufficient to prevent offset but not excessive to cause pigment loss
Solution Approach 2:
The patent combines 2-ethyl-1,3-hexanediol with C2-C4 monoalkyl ethers of polyhydric alcohols and resin in a composite formulation, where the resin adsorbs the penetrating agent and controls its release, preventing excessive penetration while maintaining rapid ink uptake
3Speed
If the wetting agent content is increased to improve penetrability, then penetrability is improved, but the wetting agent solidifies in the recording head causing thickening and ejection failure
Solution Approach 1:
The patent changes the chemical composition by selecting specific penetrating agents with appropriate molecular structures and controlling their content (2-ethyl-1,3-hexanediol: 1-5 mass%, C2-C4 monoalkyl ethers: 2-6 mass%), which provides sufficient penetrability while preventing solidification in the recording head
Solution Approach 2:
The patent uses penetrating agents that remain effective during use but do not solidify and clog the system, replacing the need for complex recovery operations and maintaining continuous operation
4Manufacturing precision
If the amount of ink ejected is increased to achieve desired image density in line head-type systems, then image density is achieved, but offset occurrence increases
Solution Approach 1:
The patent enables preliminary penetration of ink into the recording medium through optimized composition (penetrating agents and resin), so that ink is rapidly absorbed before the ejection rollers can cause offset, allowing standard ejection amounts to be used without increasing offset risk
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 ink effectively suppresses ink offset and ensures desired image density by enhancing penetrability and stability, allowing for easy recovery of ink droplet ejection state even after prolonged non-use, suitable for high-speed image formation in line head-type systems.
Implementation Method 1
an adsorbed resin proportion, obtained using the following formula from the mass of a total amount of the resin in the ink and an amount of resin separated from pigment among the resin, is at least 0.95 and less than 1.00
Data Source
AI summary
An ink for inkjet recording apparatuses is provided in which an adsorbed resin proportion calculated from a total resin mass and a free resin mass in the ink is at least 0.95 and less than 1.00, the ink containing in specific amounts, respectively: water; a pigment dispersion including a resin with a molecular weight in the range of 35,000 to 140,000 and a specific amount of pigment; glycerin and 1,3-propanediol as humectants; and 1,2-octanediol, which has 8 carbon atoms, as a high penetrating agent, and further containing a C2-C4 monoalkyl ether of a polyhydric alcohol as a penetrating agent.