Ink Jet Head Flow Path Geometry for Flaky Pigment Stability
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Solution Overview
Problem
Ink jet recording apparatuses face challenges in discharging inks containing flaky pigments due to irregular behavior in ink flow paths, leading to decreased flow rates and stability, especially with high-density piezo-based heads, which struggle to handle the unique shape and size of flaky particles.
Innovation Solution
The design includes specific ink supply paths communicating with pressure generating chambers, where the number of ink supply paths corresponds to the pressure generating chambers, and the cross-sectional areas of these paths are optimized to ensure stable ink discharge, with a piezoelectric actuator deformed in a flexural vibration manner to enhance discharging stability and rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If flaky pigment with large particle diameter is used in ink jet recording ink, then metallic glossiness is improved, but ink circulation in flow path is interrupted and discharging stability is decreased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size parameters of flaky pigment (50% average particle diameter D2 between 0.5-2.1 μm, average thickness Z between 10-30 nm) and the ink flow path dimensions (cross section area C1/C2 ratio between 1.0-3.5 times). This resolves the contradiction by finding optimal parameter ranges that allow large enough particles for metallic gloss while maintaining small enough dimensions for stable circulation and discharge.
2Manufacturing precision
If high density nozzle arrangement (≥300 dpi) is employed in piezo method, then image resolution is improved, but discharging force becomes weak and ink discharge becomes difficult
Solution Approach 1:
The patent resolves this contradiction by changing parameters of the ink and flow path rather than the nozzle structure. By controlling flaky pigment particle size (D2 ≤ 0.1 times D1 of nozzle opening) and thickness, and optimizing the ink flow path cross section area ratio (C1/C2 = 1.0-3.5 times), the ink can be discharged stably even from high-density nozzles with limited discharging force.
3Illumination intensity
If flaky pigment with large particle diameter is used, then metallic image quality is improved, but flow rate of ink is remarkably decreased
Solution Approach 1:
The patent resolves this contradiction by optimizing parameters of both the flaky pigment and the ink flow path. By controlling the particle size (D2 between 0.5-2.1 μm), thickness (Z between 10-30 nm), and the flow path cross section area ratio (C1/C2 between 1.0-3.5 times), the ink maintains sufficient flow rate while containing enough flaky pigment to produce high-quality metallic images.
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 allows for stable discharge of ink droplets at high resolutions (≥300 dpi) with flaky pigments, improving discharging stability and maintaining metallic image quality by optimizing the cross-sectional areas and particle sizes within the ink flow path.
Implementation Method 1
a piezoelectric actuator which has a vibration plate and a piezoelectric element may be formed in the ink jet recording head. The piezoelectric element may be deformed in a flexural vibration manner.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A recording apparatus includes a head, wherein a manifold in which an ink flows, and a plurality of ink flow paths divided from the manifold and arranged in a first direction are formed in the head; a nozzle opening portion discharging the ink flowing from the manifold is formed in the ink flow path; when a maximum area is C1 and a minimum area is C2 in a cross section of the ink flow path including the first direction and a vertical direction, except a cross section including the nozzle opening portion, the C1 is more than once and equal to or less than 3.5 times the C2; a length of the longest line segment among the line segments parallel to the first direction in the cross section of the ink flow path including the first direction and the vertical direction is 30 µm or more and 80 µm or less ; and the ink contains a flaky pigment having an average thickness of 5 nm or more and 50 nm or less and a 50% average particle diameter of an equivalent circle diameter of 0.5 µm or more and 2.1 µm or less.