Inkjet Printhead Via Placement for Wire Reliability
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Solution Overview
Problem
Inkjet printheads face challenges in achieving densely arranged nozzles while maintaining wire reliability and minimizing weight and cost, as increasing wire spacing to enhance reliability complicates the structure and makes it difficult to achieve weight savings and cost reduction.
Innovation Solution
The design includes a circuit board layout where through hole vias for nozzles are strategically placed inside and outside the array area, allowing wires to be concentrated on one surface, reducing the number of wires between ink channels, and using a single-layer structure with connection members on one surface to connect wires to a driving unit, thereby increasing wire spacing and nozzle density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires are spaced apart to enhance reliability, then wire reliability is improved, but device complexity increases and weight reduction becomes difficult
Solution Approach 1:
The patent transitions from a planar wire layout to a three-dimensional configuration by routing wires through the thickness of the printhead body. Through-hole vias are formed to pass wires from one surface to another, allowing wires to be positioned in multiple spatial dimensions rather than confined to a single plane, thereby achieving both reliability and compactness
Solution Approach 2:
The patent embeds through-hole vias within the printhead body structure, nesting the wire routing paths inside the solid material of the printhead. This nesting approach conceals the wire routing within the existing structure, avoiding additional external complexity while maintaining wire spacing for reliability
2Ease of manufacture
If through hole vias are placed only outside the array area, then wire routing is simplified, but nozzle density decreases
Solution Approach 1:
The patent applies different via placement strategies to different regions of the printhead. In the array area where nozzle density is critical, vias are positioned to minimize interference with nozzle spacing. Outside the array area, vias are placed for routing convenience. This localized differentiation allows each region to optimize for its primary function
Solution Approach 2:
The patent utilizes the vertical dimension by forming through-holes that penetrate the printhead thickness. This allows wire routing to occur in three dimensions rather than being constrained to the two-dimensional plane of the array area, enabling via placement that satisfies both density and manufacturing requirements
3Reliability
If a multilayered circuit board is used to increase wire spacing, then wire reliability is improved, but weight increases and cost increases
Solution Approach 1:
The patent merges the circuit board function with the printhead body into a single integrated structure. The circuit board is formed as part of the printhead body material itself, eliminating the need for separate multilayered circuit board assemblies. This integration maintains wire spacing for reliability while reducing overall weight and component count
Solution Approach 2:
The patent extracts the circuit board function from a separate multilayered structure and incorporates it directly into the printhead body. By taking out the need for discrete circuit board layers and integrating the wiring directly into the printhead material, the design achieves weight reduction while preserving electrical functionality
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 allows for densely arranged nozzles with enhanced wire reliability, effective space utilization, and cost reduction by eliminating the need for a multilayered circuit board and reducing wire density between ink channels.
Implementation Method 1
piezoelectric printheads which apply pressure to the ink in pressure chambers utilizing the displacement of piezoelectric elements to eject ink drops through nozzles
Data Source
AI summary
An inkjet printhead includes multiple sets each of which includes a nozzle, pressure chamber, and actuator; a circuit board; and a connection member. The circuit board includes a wire, through hole via, and ink channel. The connection member, which connects the wire to a driving unit, is provided outside of an array area where the sets are two-dimensionally arrayed. The number of the nozzle rows is N, and each row includes M nozzles (M and N: integer of 2 or more). The through hole vias corresponding to the nozzles of n nozzle row of the N nozzle rows are provided inside of the array area (n: 1≦n<N). The through hole vias corresponding to the nozzles of the N nozzle rows except the n nozzle row are provided outside of the array area.