Nozzle Plate Flow Path Design for Inkjet Air Entrainment
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Solution Overview
Problem
Conventional nozzle plates in inkjet heads suffer from air entrainment during ink discharge, leading to deteriorated discharge stability.
Innovation Solution
A nozzle plate design featuring a first flow path with a larger upstream cross-sectional area than downstream, and a second flow path with a smaller inclination, ensuring a sufficient volume to prevent air entrainment, with the relationship SA > 13SB between minimum cross-sectional areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional nozzle plate with a single flow path is used, then the structure is simple, but air is entrained in the inkjet head during ink drawing, deteriorating discharge stability
Solution Approach 1:
The flow path is divided into a first flow path and a second flow path that are disposed in series. The first flow path has a tapered shape with a larger cross-sectional area at the upstream side, while the second flow path has a smaller inclination angle. This segmentation allows the ink to be drawn smoothly through two stages, preventing air entrainment and improving discharge stability without excessive complexity.
Solution Approach 2:
Different sections of the flow path are given different geometric characteristics. The first flow path has a larger inclination angle and larger cross-sectional area to facilitate ink drawing, while the second flow path has a smaller inclination angle to maintain stable flow. This local differentiation optimizes each section's function, resolving the contradiction between simple structure and reliable discharge.
2Reliability
If the flow path cross-sectional area is reduced to prevent air entrainment, then discharge stability improves, but ink flow resistance increases
Solution Approach 1:
The cross-sectional area of the flow path is varied along its length. The first flow path has a larger cross-sectional area at the upstream side that gradually decreases toward the downstream side. This parameter change allows sufficient ink flow area while maintaining the ability to prevent air entrainment, thus improving discharge stability without excessive flow resistance.
Solution Approach 2:
The flow path geometry is designed to be dynamic rather than uniform. The inclination angles and cross-sectional areas change along the flow direction, with the first flow path having a steeper taper and the second having a gentler slope. This dynamic geometry adapts to the ink flow characteristics, preventing air entrainment while minimizing energy loss.
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 design enhances discharge stability by preventing air from entering the pressure chamber, improving the consistency and accuracy of ink droplet discharge.
Implementation Method 1
a first flow path, and a second flow path disposed in such a manner as to communicate with the first flow path on a downstream side... in the first flow path, a cross-sectional area orthogonal to the discharge direction on a most upstream side in the discharge direction is larger than a cross-sectional area orthogonal to the discharge direction on a most downstream side
Data Source
AI summary
Provided is a nozzle plate including a nozzle hole for discharging a droplet, in which the nozzle hole includes a first flow path, and a second flow path disposed in such a manner as to communicate with the first flow path on a downstream side of the first flow path with respect to a discharge direction of the droplet; in the first flow path, a cross-sectional area orthogonal to the discharge direction on a most upstream side in the discharge direction is larger than a cross-sectional area orthogonal to the discharge direction on a most downstream side; in a cross section including a center axis of the nozzle hole and parallel to the discharge direction; an inclination of a straight line connecting an end on the most upstream side and an end on the most downstream side of a wall surface of the second flow path disposed on one side with respect to the center axis with respect to the discharge direction is smaller than an inclination of a straight line connecting an end on the most upstream side and an end on the most downstream of the wall surface of the first flow path disposed on the one side with respect to the discharge direction; and a minimum cross-sectional area SA of the first flow path and a minimum cross-sectional area SB of the second flow path satisfy a relationship of expression (1).SA>13SB(1)