Inkjet Head Communication Channel Narrowed Part Q Factor Optimization
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Solution Overview
Problem
When the media gap between the recording medium and the inkjet head is large, high droplet speed and large droplet amount are required for stable printing, but this can lead to increased generation of satellite droplets, compromising image quality.
Innovation Solution
The inkjet head incorporates a pressure chamber with a communication channel having a narrowed part, where the Q factor is calculated to satisfy a specific formula, and the nozzle has a funnel and tapered part design to control droplet ejection effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the media gap is increased to expand printing range, then three-dimensional object printing becomes possible, but satellite droplet generation increases and image quality deteriorates
Solution Approach 1:
The patent changes the physical parameters of the communication channel (narrowing its cross-sectional area) and optimizes the Q factor of the pressure chamber to specific ranges. These parameter changes modify the ink flow characteristics and pressure dynamics, enabling stable droplet ejection with reduced satellite droplet generation even at large media gaps of 10-20mm.
Solution Approach 2:
The communication channel is designed with a localized narrowed part at a specific position, creating a region of different flow characteristics. This local structural modification controls the ink flow velocity and pressure distribution, suppressing satellite droplet formation while maintaining overall system performance for large gap printing.
2Reliability
If the droplet speed is increased to achieve stable printing at large media gap, then printing stability improves, but satellite droplet generation increases
Solution Approach 1:
The patent optimizes the Q factor of the pressure chamber to a specific range (0.75 ≤ QC < 1.5) and controls the cross-sectional area of the narrowed part to satisfy a specific formula. These parameter changes tune the resonant characteristics of the pressure chamber, enabling stable ink ejection at high speeds while suppressing satellite droplet generation through controlled pressure oscillations.
Solution Approach 2:
The actuator drives the ink in a periodic manner, utilizing the resonant frequency characteristics of the pressure chamber (controlled by the Q factor). This periodic driving creates regular pressure waves that propel ink droplets at high speed while the controlled oscillations prevent chaotic flow that would generate satellite droplets.
3Reliability
If the droplet amount is increased to achieve stable printing at large media gap, then printing stability improves, but satellite droplet generation increases
Solution Approach 1:
The patent controls the cross-sectional area of the narrowed part in the communication channel to satisfy a specific formula relating to the Q factor. This parameter control regulates the ink flow rate and droplet volume, enabling sufficient droplet amount for stable printing at large gaps while preventing excessive ink flow that would create satellite droplets.
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 further suppresses satellite droplet generation and ensures stable ink ejection, maintaining image quality even at large media gaps.
Implementation Method 1
an actuator that changes a pressure of the ink filling the pressure chamber
Implementation Method 2
QC that is a Q factor in the pressure chamber calculated by using 5.7 mPa·s as a viscosity of the ink, 1,080 kg/m3 as a density of the ink, and 1,521 m/s as a value of a speed of a sound transmitted through the ink
Data Source
AI summary
An inkjet head includes: a pressure chamber filled with ink; an actuator that changes a pressure of the ink filling the chamber; a nozzle that ejects the ink filling the chamber by the actuator being driven; and a communication channel that supplies the ink to the chamber. The communication channel has a narrowed part having a cross-sectional area perpendicular to an ejection direction of the ink smaller than any other part in the communication channel. QC that is a Q factor in the chamber calculated by using 5.7 mPa·s as a viscosity of the ink, 1,080 kg/m3 as a density of the ink, and 1,521 m/s as a value of a speed of a sound transmitted through the ink satisfies Formula (1); QC≥0.0222Sr−17.524, where Sr represents, of the narrowed part, the cross-sectional area perpendicular to the ejection direction of the ink.