Ink Jet Method Using Segmented Nozzles and Nitrogen-Containing Monomers
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Solution Overview
Problem
Existing ink jet methods face challenges in achieving high-speed printing with good color reproduction and granularity, particularly at high resolutions like 600 dpi, due to issues with ink weight and the curability of nitrogen-containing monomers leading to smudged characters and low image quality.
Innovation Solution
An ink jet method using a radiation-curable ink composition with a high proportion of monofunctional monomers and a controlled amount of nitrogen-containing monofunctional monomers, discharged at 600 dpi or more with an ink weight per dot of 22 ng or less, and irradiated with ultraviolet radiation to enhance adhesion, rub fastness, and color development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch of nozzles is increased to enable high-speed printing, then printing speed is improved, but image quality deteriorates due to insufficient resolution
Solution Approach 1:
The ink jet head is divided into multiple nozzle columns (first, second, third nozzle columns) with different nozzle pitches. Each nozzle column discharges ink at different positions in the sub-scanning direction, allowing the system to maintain high printing speed while achieving high image quality through coordinated discharge from multiple segmented nozzle groups
Solution Approach 2:
The problem is solved by transitioning from a single-dimensional nozzle arrangement to a multi-dimensional configuration. Nozzles are arranged in multiple columns offset from each other in the sub-scanning direction, creating a spatial distribution that enables both high speed and high quality printing simultaneously
2Quantity of substance
If the discharged ink weight is increased to improve color reproduction, then color development is improved, but image quality deteriorates due to smudged characters
Solution Approach 1:
Different nozzle columns discharge ink at different local positions in the sub-scanning direction. The first nozzle column discharges at a reference position, the second at a position offset by +P/N, and the third at -P/N. This local quality differentiation allows each nozzle group to contribute to different portions of the image, achieving both good color reproduction and sharp character definition
Solution Approach 2:
The ink composition parameters are optimized with specific constraints on N-vinyllactam content (0.1-10 mass %) and particle size (0.1-10 μm average diameter). These parameter changes enable the ink to maintain appropriate viscosity and curability characteristics that prevent smudging while ensuring good color reproduction
3Reliability
If the concentration of N-vinyllactam is increased to improve curability, then curability is improved, but image quality deteriorates
Solution Approach 1:
The concentration of N-vinyllactam is precisely controlled within 0.1-10 mass % of the ink composition. This parameter optimization ensures sufficient curability for proper ink drying and adhesion while preventing excessive curability that would cause poor color reproduction and reduced image quality
Solution Approach 2:
The ink is formulated as a composite material containing N-vinyllactam in controlled amounts along with other components including pigments (0.1-20 mass %), solvents, and surfactants. This composite formulation balances curability with other performance requirements, achieving both reliable drying and high 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 method enables high-speed printing with improved color development, adhesion, and rub fastness, maintaining image quality even at low ink droplet weights, and prevents smudging, especially in high-resolution printing.
Implementation Method 1
an irradiating step of irradiating, with radiation, the radiation-curable ink jet composition attached to the recording medium
Data Source
AI summary
An ink jet method includes: a discharging step of discharging a radiation-curable ink jet composition onto a recording medium at an ink weight per dot of 22 ng/dot or less by using an ink jet head having a nozzle density of 600 npi or more and configured to discharge the radiation-curable ink jet composition; and an irradiating step of irradiating, with radiation, the radiation-curable ink jet composition attached to the recording medium. The radiation-curable ink jet composition contains polymerizable compounds containing a monofunctional monomer and a multifunctional monomer. The monofunctional monomer includes a nitrogen-containing monofunctional monomer. The amount of the monofunctional monomer is 90 mass % or more relative to the total amount of the polymerizable compound. The amount of the nitrogen-containing monofunctional monomer is from 1 to 15 mass % relative to the total amount of the polymerizable compounds.