Liquid Ejection Driver IC Segmentation for Cost Reduction
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Solution Overview
Problem
The manufacturing cost of liquid ejection heads increases due to the need for high-voltage processing and large substrate areas in driver ICs, especially when correcting ejection properties for a large number of ejection orifices, which complicates the refinement and scaling of the driver ICs.
Innovation Solution
A driving device for a liquid ejection head with a control circuit unit and a drive circuit unit, where the control circuit unit stores drive voltage waveform data and transfers it to individual drive circuit sections corresponding to piezoelectric elements, allowing for the selection of appropriate waveforms to generate drive voltages, with the drive circuit unit being manufactured through high-voltage processing while the control circuit unit is not, reducing the circuit scale and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a driver IC is used to correct ejection properties for a large number of ejection orifices, then uniform ejection properties are achieved, but the substrate area and manufacturing cost increase
Solution Approach 1:
The driver IC is divided into a control circuit unit and multiple drive circuit units, where the control circuit unit stores waveform data and the drive circuit units generate drive voltages. This segmentation allows the waveform data to be shared across multiple ejection orifices, reducing the total substrate area required while maintaining uniform ejection properties through individual waveform selection for each orifice.
2Power
If high-voltage processing is used for piezoelectric elements, then high-voltage drive waveforms are achieved, but manufacturing cost and device complexity increase
Solution Approach 1:
The driver IC is segmented into a control circuit unit that operates at lower voltage and stores waveform data, and drive circuit units that generate high-voltage drive signals. This allows high-voltage processing to be localized only where needed (in the drive circuit units), reducing overall device complexity while maintaining the required high-voltage drive capability for piezoelectric elements.
3Productivity
If the number of ejection orifices is increased, then printing speed and image quality are improved, but manufacturing cost and yield degradation occur
Solution Approach 1:
Multiple drive circuit units share a common control circuit unit that stores waveform data. This merging allows the system to support a large number of ejection orifices without proportionally increasing the substrate area or manufacturing complexity, as the waveform data storage and management functions are shared across all drive circuit units, thereby reducing manufacturing cost and improving yield.
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 the correction of ejection amounts for each ejection orifice while minimizing the increase in manufacturing cost and substrate area, even with high-voltage drive requirements, by separating the high-voltage processing to the drive circuit unit, thus reducing the overall cost and complexity.
Implementation Method 1
The energy-generating element may be made of a piezoelectric material such as lead zirconate titanate (PZT) and configured to change a volume of the pressure chamber to supply and eject liquid
Data Source
AI summary
A driving device for a liquid ejection head is configured to drive a plurality of piezoelectric elements of a liquid ejection head, the liquid ejection head including a plurality of ejection orifices configured to eject liquid and the plurality of piezoelectric elements configured to generate energy for ejecting liquid from the plurality of ejection orifices. The driving device includes a control circuit unit including storage sections and transfer circuits, and a drive circuit unit including a plurality of individual drive circuit sections. The control circuit unit is an integrated circuit which is different from the drive circuit unit.