Patterned Heater Traces for Inkjet Printhead Thermal Control
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Solution Overview
Problem
Existing solid inkjet printing technologies face challenges in achieving precise thermal control of ink temperature during ejection, leading to inconsistent print quality due to inadequate heating methods, and complex manufacturing processes that increase costs and material usage.
Innovation Solution
The development of an inkjet printhead with a substrate assembly featuring resistive heater traces and a deflectable diaphragm, along with an air gap, which allows for precise temperature control of the ink and simplifies the manufacturing process by forming substructures separately and assembling them, reducing the need for complex semiconductor manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional heating methods with flexible polyimide thin film layers and metal traces are used, then the printhead can be heated to maintain ink temperature, but the thermal control precision is insufficient leading to inconsistent print quality
Solution Approach 1:
The heating system is segmented into multiple independent resistive heater traces formed directly on the printhead substrate, allowing localized and precise temperature control for each nozzle or group of nozzles, thereby improving thermal control precision and print quality consistency
Solution Approach 2:
The mechanical flexible polyimide thin film heating system is replaced with an integrated resistive heating system formed directly on the printhead substrate using semiconductor manufacturing techniques, eliminating the need for separate flexible heating layers and improving thermal control precision
2Temperature
If complex semiconductor manufacturing techniques are used to form the heater, then precise thermal control can be achieved, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The resistive heater traces are formed using the same semiconductor manufacturing processes that are already used to create other printhead components, making the manufacturing process universal and eliminating the need for specialized heating component fabrication, thereby reducing overall process complexity
Solution Approach 2:
The heater formation process is merged with the existing semiconductor manufacturing process for printhead fabrication, combining multiple functions into a single integrated process flow, which reduces manufacturing complexity while maintaining precise thermal control
3Ease of manufacture
If traditional adhesive layer assembly methods are used, then the printhead components can be assembled, but the manufacturing process becomes more complex and material usage increases
Solution Approach 1:
The complex multi-layer adhesive assembly process is extracted and replaced with a simplified direct bonding approach, removing unnecessary intermediate adhesive layers and complex assembly steps while maintaining component attachment integrity, thereby simplifying the manufacturing process
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 approach enables accurate thermal control of ink temperature, improving print quality and reducing manufacturing costs and material usage by allowing for a wider variety of materials and more efficient heat transfer, while also enabling the use of more mature manufacturing processes.
Implementation Method 1
The substrate can include a substrate having at least one resistive heater trace... and the at least one heater trace is configured to heat liquid ink flowing from the external manifold to one of the plurality of nozzles
Implementation Method 2
The substrate assembly can include a substrate having at least one resistive heater trace and a continuous, generally planar deflectable diaphragm over the substrate... with an air gap interposed between the substrate and the deflectable diaphragm
Data Source
AI summary
A printhead for an ink jet printer can be formed as a plurality of substructures which are connected subsequent to inspection and/or testing. A substructure can include a semiconductor substrate such as a silicon substrate having a plurality of heater traces which are used to maintain a temperature of melted solid ink within a tolerance of a desired temperature. The traces can be accurately formed using semiconductor processing techniques. Testing and/or inspecting the substructures prior to assembly can reduce rework and scrap, and can allow the formation of printhead structures from a wide variety of materials.