Print Head Cover Member Flatness via Segmented Wall and Sheet
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Solution Overview
Problem
Existing print head assemblies face challenges in achieving improved flatness and compatibility between the cover member and the support body, leading to potential ink contamination and suboptimal image quality due to thermal expansion mismatches and material limitations.
Innovation Solution
A print head assembly design featuring a ceramic support body with a silicon droplet forming unit, a plastic circumferential wall, and a metal sheet, where each component is formed independently to match thermal expansion coefficients and manufacturing processes, ensuring a flat and secure cover member that maintains integrity during heating and minimizes contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-material cover member is used (formed by injection molding or stamping), then the manufacturing process is simple, but the flatness and compatibility with the support body are insufficient
Solution Approach 1:
The cover member is divided into two separate components: a circumferential wall made of plastic and a sheet made of metal. Each component can be manufactured independently using optimized processes (injection molding for the circumferential wall, rolling or pressing for the sheet), and then assembled together. This segmentation allows each part to achieve its optimal flatness and compatibility characteristics while maintaining manufacturing efficiency.
2Device complexity
If the cover member is formed as a single integral component, then the structure is simple, but thermal expansion mismatches cause contamination and reduced image quality
Solution Approach 1:
Different materials are selected for different parts of the cover member based on their specific functional requirements. The circumferential wall uses plastic with thermal expansion properties matched to the support body, while the sheet uses metal with properties suited for flatness and droplet formation compatibility. This local optimization of material properties resolves thermal expansion mismatches and improves reliability without requiring a complex monolithic structure.
3Adaptability or versatility
If a single material is used for the cover member, then material selection is limited, but achieving both flatness and thermal compatibility becomes difficult
Solution Approach 1:
The cover member is constructed as a composite structure combining plastic and metal materials. The circumferential wall is made of plastic (such as PEEK or PTFE) selected for its thermal expansion compatibility with the support body, while the sheet is made of metal (such as stainless steel or titanium) selected for its ability to provide high flatness and appropriate wetting properties. This composite approach enables simultaneous optimization of multiple properties that cannot be achieved with a single material.
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
The solution achieves improved flatness and image quality by allowing for precise setting of the print gap and reducing ink contamination, while providing a wide selection of materials and manufacturing methods for each component, ensuring compatibility and longevity.
Implementation Method 1
The material of the circumferential wall may be selected, for example, to match the material of the support body in terms of thermal expansion coefficients, adhesion, or other relevant properties. Since the print head assembly heats up during use, the cover member is formed and/or mounted to compensate for thermal expansion.
Data Source
Figure 1~2
Figure 3
AI summary
A print head assembly (1) comprising: - a support body (50) from which at least one droplet forming unit (40) at least partially protrudes in a first direction (D), and - a cover member (10) surrounding the at least one droplet forming unit (40), characterized in that the cover member (10) comprises: - a circumferential wall (31) mounted on the support body (50), extending in the first direction (D), and surrounding the at least one droplet forming unit; and - a sheet (20) attached to the circumferential wall (31) and comprising an opening (22) through which the at least one droplet forming unit is accessible in the first direction. Providing the sheet and the circumferential wall as separate components allows for a wider selection of materials for each component, resulting in a cover member with a well-defined, flat end face.