Dual Flow Path Ink Jet Recording Head Bubble Suppression
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Solution Overview
Problem
Ink jet recording apparatuses with ink circulation systems face issues with ejection stability due to bubble formation in the ink flow path near the ejection orifice, leading to blank portions in images, especially when the ejection amount of ink is increased during solid image recording.
Innovation Solution
The apparatus is configured to supply ink from both the first and second flow paths to the pressure chamber, with the ink having a dynamic surface tension of 60 mN/m or less and a contact angle of 60° or less between the ink and the flow path surfaces, allowing for improved ink flow and reduced bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ink is circulated through a single flow path in an ink jet recording apparatus, then the structure is simple, but bubbles are generated in the ink flow path causing ejection instability and blank portions in images
Solution Approach 1:
The ink supply system is divided into two separate flow paths (first flow path and second flow path) that both supply ink to the pressure chamber. This segmentation allows independent ink supply channels, preventing bubble accumulation in a single path while maintaining structural simplicity through symmetrical design.
Solution Approach 2:
The inner wall surfaces of the flow paths are treated with a hydrophilic coating to create local quality differences. This hydrophilic treatment specifically at the flow path surfaces reduces contact angle to 60° or less, preventing bubble adhesion and improving ink flow stability without affecting the overall structure.
2Productivity
If the ejection amount of ink is increased for solid image recording, then productivity is improved, but the ink supplied to the ejection orifice decreases causing blank portions
Solution Approach 1:
By dividing the ink supply into two parallel flow paths, the total ink supply capacity is effectively doubled. Each flow path can independently supply ink to the pressure chamber, ensuring sufficient ink availability even during high-duty solid image recording operations.
Solution Approach 2:
The dual flow path configuration ensures continuous and stable ink supply to the pressure chamber. The hydrophilic treatment on flow path surfaces maintains continuous ink flow by preventing bubble formation and adhesion, ensuring uninterrupted ink ejection during high-productivity recording.
3Reliability
If bubble is generated in the ink flow path, then ejection stability decreases, but the root cause of bubble generation is not addressed
Solution Approach 1:
The flow path inner wall surfaces are treated with hydrophilic coating to create locally favorable conditions for ink flow. This treatment reduces the contact angle between ink and flow path surface to 60° or less, preventing bubble adhesion and generation at critical locations without requiring complete system redesign.
Solution Approach 2:
The hydrophilic treatment converts the potential harm of bubble generation into a benefit by creating surfaces that actively repel bubbles. The treated surfaces cause bubbles to detach easily and prevent their formation, transforming the flow path from a bubble-prone environment to a bubble-resistant environment.
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 configuration enhances the ejection stability of ink by minimizing bubble generation and maintaining consistent ink supply, preventing blank portions in images during high-duty recording.
Implementation Method 1
the aqueous ink has a dynamic surface tension at a lifetime of 0 milliseconds of 60 mN/m or less
Implementation Method 2
a contact angle between an inner wall surface of each of the first flow path and the second flow path and the aqueous ink is 60° or less
Data Source
AI summary
Provided is an ink jet recording method capable of suppressing a decrease in ejection stability of an ink caused by a bubble even while using an ink jet recording apparatus including a recording head of an ink circulation system. The method includes recording an image with an ink jet recording apparatus including a recording head, the recording being performed by applying an aqueous ink. The recording head is configured to allow the aqueous ink to be supplied from a first flow path or a second flow path to a pressure chamber. The aqueous ink has a dynamic surface tension at a lifetime of 0 milliseconds of 60 mN/m or less. A contact angle between an inner wall surface of each of the first flow path and the second flow path and the aqueous ink is 60° or less.