Liquid Ejection Head Port Area Optimization for Thermal Stability
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Solution Overview
Problem
In liquid ejection heads, solvent evaporation causes liquid thickening, leading to decreased droplet landing accuracy and dot formation errors, and existing solutions like supply and collection flow paths result in temperature variations affecting ejection speed and image quality.
Innovation Solution
The liquid ejection head incorporates multiple ejection opening arrays with optimized liquid supply and collection ports, where end portion supply ports have larger opening areas to reduce temperature increases and variations, ensuring consistent liquid flow and improved ejection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If liquid is forced to flow within the liquid ejection head to prevent thickening, then liquid thickening is reduced, but temperature variation occurs causing ejection speed variation
Solution Approach 1:
The liquid ejection head is divided into multiple independent ejection opening arrays (first array and second array) with separate supply and collection flow paths for each array. This segmentation allows independent temperature control and liquid flow management for each array, preventing temperature variation from affecting the entire system uniformly.
Solution Approach 2:
Different ejection opening arrays are provided with different supply and collection flow path configurations tailored to their specific thermal conditions. The first ejection opening array receives liquid from a first supply flow path and returns it to a first collection flow path, while the second array has separate second supply and second collection flow paths. This local differentiation addresses temperature variation issues specific to each array's location and thermal environment.
2Temperature
If multiple supply ports and collection ports are used, then temperature distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The multiple ports are organized into segmented groups corresponding to different ejection opening arrays. Each array has its own supply and collection ports, but the overall system manages complexity through modular organization where each segment can be independently configured and maintained.
Solution Approach 2:
The supply and collection flow paths serve multiple functions: they supply liquid to prevent thickening, control temperature distribution across different arrays, and enable independent operation of each ejection opening array. This multi-functionality reduces the need for additional separate systems.
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 reduces temperature variations at the end portions of the ejection opening arrays, enhancing the consistency of liquid ejection speed and amount, thereby improving image quality and reducing errors in droplet landing and dot formation.
Implementation Method 1
solvent components of liquid evaporate from multiple ejection openings through which liquid is ejected
Implementation Method 2
variation occurs in the temperature of the liquid flowing within the liquid ejection head, causing variation in the ejection speed
Data Source
Figure 1A~1E
Figure 2A~2C
Figure 3
AI summary
An element substrate (100) of a liquid ejection head includes an ejection opening array (14) in which multiple ejection openings (13) are arranged along a first direction, pressure chambers (23) communicating with the ejection openings, and heat generating elements (15) for ejecting liquid supplied to the pressure chambers, through the ejection openings. The element substrate also includes a first supply path (18) extending in the first direction and communicating with the pressure chambers, a first collection path (19) communicating with the pressure chambers, multiple liquid supply ports (21a) communicating with the first supply path at different positions in the first direction, and a liquid collection port (21b) communicating with the first collection path. At least a liquid supply port (21al, 21a2) of the liquid supply ports located at an end portion in the first direction has an opening area larger than the opening area of the liquid collection port.