Actuator Wake Waveform Stabilization for Inkjet Print Quality

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Solution Overview

Problem

Existing liquid discharge apparatuses, such as ink jet printers, face issues with maintaining print quality due to the rapid change in actuator characteristics when bias voltage is applied, leading to suboptimal ink discharge and resulting in deteriorated print quality.

Innovation Solution

The apparatus employs a wake waveform to gradually increase the actuator voltage and maintain it for a period equal to or longer than two discharge cycles, followed by a sleep waveform to decrease the voltage, allowing the actuator to stabilize before discharging ink, thereby preventing premature ink discharge and maintaining print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

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

Engineering Contradiction:
Improveactuator lifespanVSAvoidprint quality
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies a wake waveform to the actuator before resuming ink discharge after bias voltage suspension. This preliminary action stabilizes the actuator characteristics by gradually increasing the voltage from 0V to the bias voltage level over a specified period (equal to or longer than two discharge cycles), preventing rapid characteristic changes that would otherwise cause poor print quality. This allows the system to maintain actuator lifespan while ensuring print quality is not compromised.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the bias voltage is applied for a longer period before discharge, then the actuator characteristics are stabilized, but the time for ink discharge is increased

Engineering Contradiction:
Improveactuator characteristics stabilityVSAvoidtime for ink discharge
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent implements a periodic voltage application pattern where the wake waveform is applied for a specific duration (equal to or longer than two discharge cycles) before resuming normal ink discharge. This periodic approach ensures the actuator characteristics are stabilized without excessively extending the overall discharge time, as the wake waveform period is carefully controlled to be the minimum necessary for stabilization.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the wake waveform is applied for a longer duration, then the print quality is improved, but the productivity is reduced

Engineering Contradiction:
Improveprint qualityVSAvoidprinting speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent optimizes the wake waveform application duration to be equal to or longer than two discharge cycles, which is the minimum period required to stabilize actuator characteristics and prevent the first dot from becoming dark. This parameter optimization ensures print quality is maintained while minimizing the impact on printing speed, as extending the duration beyond this threshold would provide diminishing returns on quality while continuing to reduce productivity.

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

This approach stabilizes the actuator characteristics during liquid discharge, ensuring consistent and improved print quality by extending the time before applying bias voltage and maintaining it after discharge, preventing the first dot from becoming dark and enhancing overall printing performance.

Implementation Method 1

Each channel includes a piezoelectric drive type electrostatic capacitance actuator

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3715131B1Liquid discharge apparatus
Publication Date: 2022.12.07 TOSHIBA TEC KK
  • EP3715131B1 patent drawingFigure 1
  • EP3715131B1 patent drawingFigure 2
  • EP3715131B1 patent drawingFigure 3

AI summary

A liquid discharge apparatus includes an actuator and a drive circuit. The actuator is configured to cause liquid to be discharged from a nozzle corresponding thereto. The drive circuit is configured to apply a wake waveform to the actuator such that a voltage of the actuator increases to a first voltage and then is maintained at the first voltage without discharge of liquid from the nozzle. A drive waveform is then applied to the actuator for each of one or more discharge cycles such that liquid is discharged from the nozzle for each of the discharge cycles. A time from when the wave waveform starts to be applied to the actuator to when the drive waveform starts to be applied to the actuator is equal to or longer than a period of time of two discharge cycles.