Capacitive Load Driving Circuit Layout for Piezo Print Stability

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Solution Overview

Problem

High-speed and high-resolution printing in ink jet printers using piezoelectric elements faces challenges with energy efficiency and operational failures due to increased switching frequency in class D amplification, leading to reduced energy efficiency and heat generation.

Innovation Solution

A liquid discharging apparatus with a modulation circuit, transistor, and low pass filter configuration that reduces parasitic inductance and enhances heat dissipation, allowing for higher frequency drive signals and improved printing quality by optimizing the frequency range of the modulation signal between 1 MHz and 8 MHz.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the switching frequency of class D amplification is increased to increase the frequency of drive signal, then high-speed and high-resolution printing is enabled, but energy efficiency is reduced and heat generation increases

Engineering Contradiction:

Improveprinting speed and resolutionVSAvoidenergy efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent optimizes the switching frequency parameter within a specific range (1-8 MHz) to balance printing performance and energy efficiency. By carefully selecting and controlling the frequency parameter, the system achieves high-speed printing while preventing excessive energy loss and heat generation that would occur at higher frequencies.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a class D amplification circuit that maintains continuous switching operation at optimized frequencies, ensuring sustained high-performance printing output. The continuous operation at controlled frequency prevents energy efficiency degradation while maintaining productive output.

Inventive Principle:

Principle #20Continuity of useful action

2Speed

If the switching frequency of class D amplification is increased to increase the frequency of drive signal, then high-speed printing is enabled, but operational failures due to noise and heat generation occur

Engineering Contradiction:

Improveink discharge frequencyVSAvoidoperational stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent constrains the switching frequency within an optimized range (1-8 MHz) to achieve high ink discharge frequency while preventing operational failures. This parameter optimization ensures that the system operates at speeds necessary for high-performance printing without exceeding the threshold where noise and heat cause reliability issues.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements monitoring and control mechanisms that adjust operating parameters based on detected conditions, preventing operational failures before they occur. By continuously managing the switching frequency and related parameters, the system maintains reliable operation at high speeds.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the switching frequency is increased to increase drive signal frequency, then high-resolution printing is enabled, but loss due to switching increases

Engineering Contradiction:

Improveprinting resolutionVSAvoidswitching loss

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent optimizes the switching frequency parameter to a specific range (1-8 MHz) that enables high-resolution printing by achieving sufficient drive signal frequency while minimizing switching losses. This precise parameter control allows the system to achieve manufacturing precision goals without excessive energy waste from frequent switching operations.

Inventive Principle:

Principle #35Parameter changes

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

Enables high-speed and high-resolution printing with reduced operational failures and improved energy efficiency by preventing voltage noise overshoot and increasing heat dissipation, maintaining the advantages of class D amplification.

Implementation Method 1

a piezoelectric element which is displaced by receiving a drive signal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a configuration in which a source signal is subjected to class D amplification

Methodology Applied

Scientific EffectClass D amplification:

Implementation Method 3

a low pass filter which generates a drive signal by smoothening the amplified modulation signal

Methodology Applied

Scientific EffectLow pass filtering: Filter (electronic)

Data Source

PatentUS9654099B2Driving circuit for driving a capacitive load

Publication Date: 2017.05.16 SEIKO EPSON CORP

AI summary

Provided is a driving circuit for driving a capacitive load which includes a modulation circuit which generates a modulation signal which is obtained by pulse-modulating a source signal, a transistor which generates an amplified modulation signal by amplifying the modulation signal, a low pass filter which generates a drive signal by smoothening the amplified modulation signal, a piezoelectric element which is displaced by receiving the drive signal, and a circuit substrate on which the transistor is mounted. The transistor includes a first electrode, a second electrode, a third electrode, and a clip which has conductivity, is electrically connected to the first electrode. Furthermore, the circuit substrate has a first land corresponding to the first electrode, a second land corresponding to the second electrode, and a third land corresponding to the third electrode. In addition, a part of the clip is connected to the third land.