High-Speed Inkjet Head Spacing and Ink Composition for Image Quality
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Solution Overview
Problem
High-speed ink jet recording methods face challenges in maintaining ink jettability and achieving high image quality due to nozzle drying and reduced landing intervals.
Innovation Solution
The method involves jetting a first ink from an upstream ink jet head and a second ink from a downstream head, with specific mass ratios of organic solvent to pigment and resin particle contents, and a controlled distance between the heads to enhance jettability and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed ink jet recording is performed with fast substrate transportation, then productivity is improved, but ink jettability deteriorates due to nozzle drying
Solution Approach 1:
The ink jet recording system is divided into multiple ink jet heads (first ink jet head and second ink jet head) positioned at different locations. Each head handles specific ink jetting tasks, allowing the system to maintain high substrate transportation speed while ensuring proper ink delivery through distributed nozzle arrangements and differentiated ink composition ratios.
2Productivity
If high-speed ink jet recording is performed with fast substrate transportation, then productivity is improved, but image quality deteriorates due to reduced landing intervals
Solution Approach 1:
The first ink jet head performs preliminary ink jetting on the substrate before the second ink jet head adds additional ink. This sequential preliminary action allows each ink jet head to operate with adequate landing intervals even at high substrate transportation speeds, ensuring proper ink deposition and image quality without compromising productivity.
3Device complexity
If multiple ink jet heads are positioned close together to maintain compact device size, then device complexity is reduced, but ink drying increases due to shorter distance between heads
Solution Approach 1:
Different ink compositions are used in the first and second ink jet heads, with specific mass ratios of organic solvent to pigment and resin particles optimized for each head's position and function. This local quality differentiation allows the first ink jet head (upstream) to use ink formulations that resist drying better, compensating for the shorter distance between heads and reduced landing intervals at high substrate transportation speeds.
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
This approach effectively suppresses ink drying and improves landing interference, resulting in high-quality images during high-speed recording.
Implementation Method 1
both of the first ink and the second ink contain a pigment and an organic solvent, a mass ratio S1 of a content of an organic solvent having a SP value of 28 MPa 1/2 to a content of the pigment in the first ink is 0.5 to 1.6, and a mass ratio S2 of the content of the organic solvent having a SP value of 28 MPa 1/2 to the content of the pigment in the second ink is 1.6 to 5.0
Data Source
Figure 1
AI summary
An ink jet recording method includes: a step of jetting a first ink from a first ink jet head positioned on an upstream side in a transport direction to a substrate that is being transported at a transportation speed of 80 m/min or more; and a step of jetting a second ink from a second ink jet head positioned on a downstream side in the transport direction to the substrate, in which a distance between the first ink jet head and the second ink jet head is 100 mm to 500 mm, both of the first ink and the second ink contain a pigment and an organic solvent, a mass ratio S1 of a content of an organic solvent having a SP value of 28 MPa1/2 or less to a content of the pigment in the first ink is 0.5 to 1.6, and a mass ratio S2 of a content of an organic solvent having a SP value of 28 MPa1/2 or less to a content of the pigment in the second ink is more than 1.6 and 5.0 or less.