Inkjet Ink Formulation for High Density Single-Pass Printing
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Solution Overview
Problem
Single-pass inkjet printing using line-type recording heads results in low image density and ink blurring due to inability to overlay images, and the phenomenon of strike-through, where ink penetrates excessively into the recording medium, leading to inferior image quality.
Innovation Solution
An inkjet ink formulation comprising a pigment, first particles with a resin containing a high percentage of methyl methacrylate repeating units, and second particles with a lower methyl methacrylate content, along with a moisturizing agent like α,ω-alkanediol, which enhances ejection stability and image density by preventing nozzle drying and ink dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single-pass inkjet printing is used with line-type recording heads, then printing speed is improved, but image density decreases and images cannot be overlaid
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by incorporating a specific resin emulsion with controlled acid value (50-150 mg KOH/g) and molecular weight (10,000-100,000). This parameter change in the ink formulation enables sufficient pigment deposition and image density achievement in single-pass printing without requiring multiple passes, thus resolving the contradiction between printing speed and image density.
2Productivity
If single-pass inkjet printing is used with line-type recording heads, then printing speed is improved, but ink blurring occurs due to inability to overlay images
Solution Approach 1:
The patent employs a composite ink formulation containing pigment particles, resin emulsion, and specific additives. The resin emulsion acts as a binding matrix that holds pigment particles together, creating a stable composite structure that prevents ink blurring and maintains image quality in single-pass printing, while the overall formulation is optimized for rapid drying and fixation.
3Strength
If conventional resin emulsion is used in ink, then adhesion to non-absorbent substrate is improved, but chemical resistance decreases due to high acid value
Solution Approach 1:
The patent precisely controls the acid value parameter of the resin emulsion within the range of 50-150 mg KOH/g, which is lower than conventional resins. This parameter optimization achieves a balance where the resin maintains sufficient adhesion to non-absorbent substrates while exhibiting improved chemical resistance, resolving the trade-off between these two properties.
4Quantity of substance
If ink excessively penetrates into recording medium, then absorption is improved, but strike through occurs and image quality deteriorates
Solution Approach 1:
The patent formulates the ink with controlled viscosity and composition to achieve partial penetration into the recording medium for sufficient absorption and fixation, while the resin emulsion and pigment particle structure prevent excessive penetration that would cause strike-through. This controlled partial action optimizes both absorption and image quality.
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 formulation ensures excellent ejection stability and increased copy density, preventing strike-through and improving image quality by maintaining ink on the surface and inhibiting nozzle drying, thus enhancing the overall performance of single-pass inkjet printing.
Implementation Method 1
The nozzles of the inkjet recording head eject the inkjet ink to form dots on the recording medium conveyed by the conveyance section
Implementation Method 2
The second resin has a content percentage of the repeating unit derived from methyl methacrylate of less than 30% by mass relative to all repeating units included in the second resin
Implementation Method 3
an inkjet ink excellent in balance between chemical resistance and adhesion to a non-absorbent substrate can be obtained
Implementation Method 4
The moisturizing agent includes an α,ω-alkanediol
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An inkjet ink includes a pigment, first particles containing a first resin, second particles containing a second resin, and a moisturizing agent. The first resin includes a repeating unit derived from methyl methacrylate at a content percentage of at least 30% by mass and no greater than 70% by mass relative to all repeating units included in the first resin. The second resin has a content percentage of the repeating unit derived from methyl methacrylate of less than 30% by mass relative all repeating units included in the second resin. The moisturizing agent includes an α,ω-alkanediol. An inkjet recording system (100) includes a conveyance section (1) and an inkjet recording head (11) including a plurality of nozzles (12) that eject the inkjet ink to form dots on a recording medium (P) conveyed by the conveyance section.