Liquid Ejection Head Common Electrode Segmentation
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Solution Overview
Problem
In liquid ejection heads with a common electrode, the drive waveform difference between the end and center nozzles leads to deteriorated print quality, including larger dot diameters and reduced linearity.
Innovation Solution
A liquid ejection head design that includes a common electrode formed on the substrate and the inner peripheral surface of a long supply hole, along with individual electrodes for each pressure chamber, allowing for simultaneous driving of pressure chambers while minimizing resistance and maintaining print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common electrode is used to bundle electrodes of pressure chambers near the center of the substrate, then device complexity is reduced and manufacturing is simplified, but resistance increases and print quality deteriorates due to drive waveform differences between end and center nozzles
Solution Approach 1:
The common electrode is segmented into multiple regions along the substrate length direction, with each region having a different potential. This segmentation allows the electrode to provide both the simplification of a common electrode structure and the precision of individually controlled drive waveforms for different nozzle groups, resolving the contradiction between device complexity and manufacturing precision
Solution Approach 2:
Different regions of the common electrode are assigned different potentials to create locally optimized drive waveforms. The electrode structure transitions from a uniform common potential to a spatially varying potential distribution, enabling local quality control that maintains print quality while preserving the simplified common electrode architecture
2Ease of operation
If electrodes of non-ejecting air chambers are led out towards the driver IC side, then ease of operation is improved, but the drive waveform difference between end and center nozzles increases, worsening print quality
Solution Approach 1:
The air chamber electrodes are segmented and connected to different potential regions of the common electrode. This segmentation allows air chambers to be easily connected towards the driver IC side while maintaining the segmented potential distribution that ensures consistent drive waveforms across all nozzles, resolving the contradiction between ease of operation and manufacturing precision
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 design effectively suppresses the deterioration of print quality even when using a common electrode, by reducing the resistance and ensuring consistent ejection performance across all nozzles.
Implementation Method 1
an actuator formed of piezoelectric ceramics
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A liquid ejection head includes a plate with a plurality of nozzles arranged along a first direction through which liquid is ejected. A substrate is on the plate and includes a hole extending along the first direction by which the liquid is supplied. An actuator is on the substrate along the hole, The actuator has a plurality of pressure chambers, from which the liquid from the hole is ejected by the nozzles, and a plurality of air chambers. Each air chamber is between two of the pressure chambers that are adjacent to each other. A plurality of individual electrodes is formed on the substrate and each is connected to a corresponding one of the pressure chambers. A common electrode is formed on the substrate and an inner peripheral surface of the hole.