Inkjet Printhead Encapsulant Height Control via Depressing Plate
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Solution Overview
Problem
The existing methods for controlling the height of the encapsulant on an inkjet printhead are inadequate, leading to increased media gap and print quality issues due to high encapsulant height and the cockle phenomenon, with existing materials and dispensing processes being unstable and prone to contamination.
Innovation Solution
A method to control the encapsulant height by depressing the encapsulant material from a first height to a second, lower height using a depressing plate before or after curing, or by machining the cured encapsulant to achieve a stable and reduced height, thereby minimizing media gap and improving print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the encapsulant height is reduced to minimize media gap, then print quality is improved, but the electrical connections become more vulnerable to corrosion
Solution Approach 1:
The encapsulant is applied with varying thickness: a first thickness at the edges and a second, greater thickness at the center where electrical connections are located. This local variation in encapsulant thickness provides enhanced corrosion protection at critical areas while maintaining overall compactness
Solution Approach 2:
A barrier layer is deposited on the substrate before applying the encapsulant material. This preliminary protective layer ensures that even if the encapsulant height is reduced, the electrical connections remain protected from corrosion through the combined barrier and encapsulant layers
2Ease of manufacture
If a discharge needle process is used to dispense encapsulant, then the process is simple, but the encapsulant height varies and is undesirably high
Solution Approach 1:
A barrier layer is introduced as an intermediary between the substrate and the encapsulant material. This barrier layer serves as a reference surface that enables precise control of the encapsulant thickness, allowing the dispensing process to achieve consistent height without complex adjustments
Solution Approach 2:
The viscosity of the encapsulant material is modified by adding a thickening agent. This parameter change allows the material to maintain its desired profile during dispensing and curing, achieving consistent height control without requiring complex dispensing mechanisms
3Manufacturing precision
If stencil printing is used to apply encapsulant, then consistent layer application is achieved, but encapsulant may stick to the stencil causing contamination
Solution Approach 1:
The barrier layer acts as an intermediary surface that prevents the encapsulant material from directly contacting the stencil during the printing process. This eliminates the sticking and contamination issues while maintaining the precision benefits of stencil printing
4Manufacturing precision
If a profiling surface is used to wipe the encapsulant, then height is reduced, but encapsulant residues splatter causing contamination
Solution Approach 1:
The barrier layer is deposited beforehand to establish a precise reference surface. This preliminary action eliminates the need for subsequent profiling or wiping operations, as the encapsulant thickness is controlled during the application process itself, preventing residue generation
Data Source
AI summary
A method of controlling a height of an encapsulant material on an inkjet printhead is provided. The method includes dispensing the encapsulant material on an outer portion of the inkjet printhead. The encapsulant material is then depressed to reduce its height on the outer portion of the inkjet printhead. The encapsulant material may be depressed directly after dispensing or before it completely cures. The encapsulant material may be completely cured before reducing its height. The height of the cured encapsulant material may be reduced by removing a top portion of the encapsulant material through machining operation. Reducing the height of the encapsulant material on the inkjet printhead minimizes the distance of the nozzle plate of the inkjet printhead to the printing media, thus improving print quality.