Actuator Drive Circuit Voltage Stabilization

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Solution Overview

Problem

Existing liquid discharge apparatuses, such as ink jet printers, face challenges in maintaining print quality due to the inability to freely adjust the application time of bias voltage, leading to actuator characteristic changes that affect print quality.

Innovation Solution

An actuator drive circuit that includes a signal processing circuit to detect gradation scale data commands, applying sleep and wake waveforms to actuators, and a bias hold waveform to maintain voltage, allowing for stabilization of actuator characteristics during discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bias voltage application is suspended to prevent actuator deterioration, then the actuator reliability is improved, but the print quality deteriorates due to actuator characteristic changes

Engineering Contradiction:
Improveactuator reliabilityVSAvoidprint quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies a preliminary action by introducing a wake waveform before the discharge waveform when resuming printing after bias voltage suspension. This wake waveform gradually restores the actuator characteristics that changed during the bias voltage suspension period, ensuring smooth transition and maintaining print quality while still allowing the bias voltage to be suspended for reliability improvement.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the bias voltage application time is extended to stabilize actuator characteristics, then the print quality is improved, but the actuator deterioration accelerates

Engineering Contradiction:
Improveprint qualityVSAvoidactuator reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements periodic action by alternating between suspending the bias voltage during idle periods and applying it during printing periods. This periodic on-off pattern allows the actuator to be protected from continuous bias voltage exposure (improving reliability) while still receiving sufficient bias voltage application during printing to maintain stable characteristics and print quality.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the bias voltage is applied continuously to maintain actuator characteristics, then the print quality is maintained, but the energy consumption increases

Engineering Contradiction:
Improveprint qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts the bias voltage application from continuous operation, removing it during idle periods when printing is not performed. This extraction reduces energy consumption significantly while the wake waveform mechanism ensures that actuator characteristics are properly restored before printing resumes, maintaining print quality without continuous bias voltage application.

Inventive Principle:
Principle #2Taking out (Extraction)

4Use of energy by moving object

If the bias voltage application is suspended frequently to save energy, then the energy consumption is reduced, but the print quality becomes unstable

Engineering Contradiction:
Improveenergy consumptionVSAvoidprint quality stability
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent implements feedback by monitoring the printing state and automatically controlling the bias voltage application accordingly. When printing is detected, the bias voltage is applied; when idle, it is suspended. This feedback-based control ensures energy savings during idle periods while maintaining print quality stability during active printing, resolving the contradiction between energy consumption and print quality stability.

Inventive Principle:
Principle #23Feedback

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 the suspension of bias voltage application and stabilization of actuator characteristics, thereby improving print quality by allowing flexible adjustment of voltage application times.

Implementation Method 1

An ink jet head, which is the liquid discharge apparatus of the ink jet printer, includes a piezoelectric drive type actuator as a drive apparatus that discharges ink from a nozzle

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3715130B1Actuator drive circuit of liquid discharge apparatus
Publication Date: 2024.07.31 RISO TECH CORP
  • EP3715130B1 patent drawingFigure 1
  • EP3715130B1 patent drawingFigure 2
  • EP3715130B1 patent drawingFigure 3

AI summary

An actuator drive circuit of a liquid discharge apparatus includes a discharge waveform generating circuit, a sleep waveform generating circuit, and a wake waveform generating circuit. The discharge waveform generating circuit is configured to generate a plurality of drive waveforms to be applied to actuators of the liquid discharge apparatus for liquid discharge. The drive waveforms correspond to gradation values of gradation scale data. The sleep waveform generating circuit is configured to generate a sleep waveform to be applied to the actuators. The sleep waveform causes a voltage of the actuators to transition to a first voltage without liquid discharge. The wake waveform generating circuit is configured to generate a wake waveform to be applied to the actuators. The wake waveform causes the voltage of the actuators to transition to a second voltage higher than the first voltage without liquid discharge.