Inkjet Drive Circuit Layout for Stable Piezoelectric Ejection

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Solution Overview

Problem

Existing liquid ejecting apparatuses, such as ink jet printers, face instability in the operation of integrated circuits due to the arrangement of circuits and terminals, leading to potential malfunctions, particularly in the drive circuit that operates piezoelectric elements for ink ejection.

Innovation Solution

The proposed solution involves a specific configuration of the drive circuit and integrated circuit within the liquid ejecting apparatus, including a drive signal selection control circuit, power supply voltage control circuit, and discharge circuit, which optimizes the arrangement of components like the modulation circuit, amplifier circuit, and demodulation circuit to improve signal propagation and reduce interference, thereby stabilizing the operation of the piezoelectric elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If multiple circuits (modulation circuit, amplifier circuit, demodulation circuit, discharge circuit) are integrated into a single integrated circuit, then the device complexity is reduced and integration is improved, but the reliability deteriorates due to potential malfunctions from circuit arrangement and terminal positioning

Engineering Contradiction:
Improvecircuit integrationVSAvoidoperation stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The integrated circuit is divided into multiple mounting areas, each dedicated to specific circuits (modulation circuit, amplifier circuit, demodulation circuit, discharge circuit). This segmentation isolates potential malfunction sources and improves reliability while maintaining integration benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A ground terminal is introduced as an intermediary element positioned between different circuit mounting areas. This ground terminal acts as a reference potential barrier that reduces signal interference and stabilizes circuit operation, particularly protecting the demodulation circuit from noise generated by other circuits.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If circuits are arranged in a compact integrated circuit, then the area is reduced and integration is improved, but signal interference increases due to wiring impedance and proximity of circuits

Engineering Contradiction:
Improveintegrated circuit areaVSAvoidsignal interference
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The integrated circuit substrate is divided into distinct mounting areas for different circuits, physically separating signal paths and reducing electromagnetic interference between circuits while maintaining compact overall area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Ground terminals are positioned as intermediary elements between circuit mounting areas, providing a low-impedance reference path that shields sensitive circuits from noise and reduces signal interference in the compact integrated layout.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances the stability and accuracy of ink ejection by reducing the influence of wiring impedance and signal interference, leading to improved inkjet performance and reduced malfunctions.

Implementation Method 1

a piezoelectric element such as a piezo element are known. Such a piezoelectric element is provided corresponding to a plurality of nozzles for ejecting ink

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3842231B1Liquid ejecting apparatus, drive circuit, and integrated circuit
Publication Date: 2023.09.20 SEIKO EPSON CORP
  • EP3842231B1 patent drawingFigure 1
  • EP3842231B1 patent drawingFigure 2
  • EP3842231B1 patent drawingFigure 3

AI summary

A liquid ejecting apparatus includes a liquid ejecting head ejecting a liquid by supplying a drive signal to a drive element, and a drive circuit. The drive circuit includes an integrated circuit, an amplifier circuit, and a demodulation circuit. The integrated circuit includes a modulation circuit that modulates the base drive signal to output a modulation signal, a switching circuit that outputs the amplification control signal according to the modulation signal, a discharge circuit, a constant voltage output circuit that outputs a DC voltage signal, and an output terminal from which the DC voltage signal is output. The constant voltage output circuit and the discharge circuit are electrically coupled to the output terminal, and a shortest distance between the output terminal and the constant voltage output circuit is shorter than a shortest distance between the output terminal and the discharge circuit.