Liquid Ejection Head Asymmetric Ink Supply Ports
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Solution Overview
Problem
Conventional liquid ejection heads in inkjet printing face issues with density unevenness due to satellite droplets being affected by air currents and bubbles remaining in the common liquid chamber, leading to reduced throughput and image quality.
Innovation Solution
A liquid ejection head design with ink supply ports arranged on both sides of the ejection ports, forming a common liquid chamber, and using electrothermal transducers to generate heat, which allows balanced ink flow and bubble growth, preventing bubbles from remaining in the chamber and improving droplet ejection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ink is supplied from a single liquid supply port to the common liquid chamber, then the structure is simple, but bubbles remain in the chamber and satellite droplets are generated causing density unevenness
Solution Approach 1:
The single liquid supply port is segmented into multiple liquid supply ports (first and second liquid supply ports) positioned at different locations to communicate with the common liquid chamber. This segmentation enables ink to be supplied from multiple directions, preventing bubble accumulation and improving ejection uniformity without significantly increasing structural complexity.
Solution Approach 2:
The liquid supply ports are asymmetrically positioned relative to the ejection ports and common liquid chamber. The first liquid supply port is positioned on one side and the second on the other, creating an asymmetric flow pattern that prevents bubbles from remaining in the chamber and ensures uniform ink distribution to all ejection ports.
2Manufacturing precision
If the number of ejection ports is increased for high-resolution printing, then printing quality improves, but the distance between ejection ports increases causing density unevenness
Solution Approach 1:
Instead of increasing the distance between ejection ports in one dimension to accommodate more ports, the invention uses multiple liquid supply ports positioned at different locations (different dimensions) to supply ink to the common liquid chamber. This multi-dimensional approach allows high-resolution printing with closely spaced ejection ports while maintaining uniform ink supply.
3Device complexity
If satellites are ejected toward the common liquid chamber, then the ejection mechanism is simple, but satellites become mist floating inside the printer housing instead of impacting the print medium
Solution Approach 1:
The liquid supply ports are positioned asymmetrically to create asymmetric flow patterns in the common liquid chamber. This asymmetric ink supply prevents bubbles from forming and ensures that satellites are consistently ejected toward the ejection ports and impact the print medium accurately, rather than floating as mist inside the housing.
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 enables stable ejection of droplets at high driving frequencies with dense nozzle arrangements, reducing density unevenness and mist formation, thus enhancing print quality and throughput.
Implementation Method 1
Heaters 509 are each located at a position corresponding to one of the ejection ports 506 and serves as an ejection energy generating element that supplies ejection energy to a liquid in the pressure chamber 508
Implementation Method 2
bubbles generated by the heaters 509 grow disproportionately from the pressure chamber 508 toward the liquid supply port 505
Data Source
AI summary
A print head that ejects ink supplied through an ink supply port can prevent the size of satellites from being reduced while inhibiting an increase in resistance to an ink flow. In the print head, ink supply ports are arranged on both sides of a plurality of channels. A predetermined number of ink supply ports are arranged at least at one side of the ink channel all over the range of the arrangement of the channels. One side of each of the plurality of channels is connected via the common liquid chamber to the liquid supply port located so as to extend in a direction in which the channels are arranged.