Liquid Discharge Head Drive Waveform Control for Mist Suppression

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Solution Overview

Problem

Inkjet heads with multi-drop liquid discharge systems often produce tails on ink droplets, leading to mist formation during flight, which deteriorates print quality due to satellite droplet scattering.

Innovation Solution

A liquid discharge head with an actuator and drive circuit that applies a first drive waveform for discharging ink droplets at a fast speed, followed by a second drive waveform at a slower speed to prevent mist formation by allowing the last droplet to absorb the tail of the preceding droplet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ink droplets are discharged at high speed to improve productivity, then discharge speed increases, but mist formation occurs due to tail scattering

Engineering Contradiction:
Improvedischarge speedVSAvoidmist formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic pulse signals to the actuator to discharge ink droplets in a controlled sequence. By using periodic actions with different frequencies (first frequency for initial droplets, second frequency for final droplet), the system achieves both high productivity and mist suppression

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts the discharge speed by applying different drive waveforms at different stages. The actuator is driven at a first frequency for most droplets and switches to a second frequency for the final droplet, creating dynamic speed variation that prevents mist while maintaining overall productivity

Inventive Principle:
Principle #15Dynamics

2Productivity

If multiple ink droplets are discharged to form one dot, then productivity increases, but tail formation on droplets causes satellite droplet scattering

Engineering Contradiction:
Improvemulti-drop dischargeVSAvoidprint quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses periodic pulse signals with varying frequencies to control multi-drop discharge. The first frequency generates multiple droplets for productivity, while the second frequency (applied to the final droplet) ensures precise placement without satellite droplets, thus maintaining print quality

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the drive frequency parameter dynamically during the discharge process. By switching from a first frequency to a second frequency for the final droplet, the system optimizes both productivity (through multi-drop discharge) and print quality (by preventing satellite droplet formation)

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

The solution effectively suppresses mist formation, enhancing print quality by ensuring the last ink droplet is discharged at a slower speed to absorb the tail of the preceding droplet, thereby preventing satellite droplet scattering.

Implementation Method 1

an actuator that is configured to expand and contract pressure chambers

Methodology Applied
Scientific EffectPressure change: Pressure Increase

Data Source

PatentEP3702159B1Liquid discharge head and printer
Publication Date: 2022.11.02 TOSHIBA TEC KK
  • EP3702159B1 patent drawingFigure 1
  • EP3702159B1 patent drawingFigure 2~3
  • EP3702159B1 patent drawingFigure 4~5

AI summary

A liquid discharge head includes an actuator and a drive circuit. The actuator is configured to expand and contract a pressure chambers. The drive circuit is configured to apply a first drive waveform to cause the actuator to discharge a liquid droplet at a first speed, and then a second drive waveform after the first drive waveform to cause the actuator to discharge a liquid droplet at a second speed slower than the first speed.