Droplet Ejection Device Variable Recovery Control

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Solution Overview

Problem

Existing droplet ejection devices, such as inkjet printers, face inefficiencies in recovery operations due to indiscriminate drying prevention methods, leading to wasteful liquid and power consumption, as they do not account for the varying volumes of droplets being ejected, affecting ejection performance and image quality.

Innovation Solution

A droplet ejection device with a controller that determines the volume of the first droplet to be ejected and sets conditions for recovery control, including drying prevention driving and flushing, based on this volume, to optimize energy and liquid usage, reducing wasteful recovery operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drying prevention driving is performed with fixed conditions regardless of droplet volume, then ejection performance can be maintained, but liquid consumption and power consumption increase wastefully

Engineering Contradiction:
Improveejection performanceVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the recovery operation conditions variable rather than fixed. The controller dynamically adjusts the number of drive pulses, pulse width, and driving frequency based on the detected droplet volume. When droplet volume is small, the system applies stronger recovery operations more frequently; when droplet volume is large, recovery operations are reduced or skipped, thereby optimizing power consumption while maintaining ejection performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes multiple parameters of the recovery operation based on droplet volume conditions. These parameters include the number of drive pulses applied to the actuator, the pulse width duration, and the driving frequency. By adjusting these parameters dynamically, the system achieves appropriate recovery operations matched to actual ejection needs, reducing wasteful energy consumption.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If flushing is performed frequently to prevent drying, then ejection reliability is maintained, but liquid consumption increases

Engineering Contradiction:
Improveejection reliabilityVSAvoidliquid consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies local quality by tailoring recovery operations to specific local conditions - namely the actual droplet volume being ejected. Instead of uniform flushing of all nozzles regardless of usage patterns, the system identifies nozzles that actually require recovery based on their ejection characteristics. This localized approach ensures reliable ejection where needed while minimizing liquid waste in nozzles that don't require flushing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements feedback by detecting the actual droplet volume ejected during recording operations and using this information to control recovery operations. The controller monitors ejection characteristics and adjusts flushing frequency and intensity accordingly. This closed-loop feedback mechanism ensures that flushing is performed only when necessary, maintaining ejection reliability while reducing liquid consumption.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If recovery operation cycle is extended to reduce frequency, then power consumption decreases, but drying prevention becomes insufficient

Engineering Contradiction:
Improvepower consumptionVSAvoiddrying prevention
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies dynamics by making the recovery cycle length variable rather than fixed. The controller dynamically adjusts the cycle period based on droplet volume detection results. When small droplets are detected, the system shortens the recovery cycle to prevent drying more aggressively. When large droplets are detected, the cycle is extended or recovery operations are skipped. This dynamic adjustment optimizes the balance between power consumption and drying prevention effectiveness.

Inventive Principle:
Principle #15Dynamics

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 enhances economic efficiency by minimizing wasteful recovery operations, conserving liquid and power, and improving ejection performance by tailoring recovery controls to the specific volume of droplets being ejected.

Implementation Method 1

a drive pulse is applied to a piezoelectric actuator to change the volume of pressure chambers filled with ink and communicating with nozzles

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a pulse group including plural non-ejection drive pulses is applied to an actuator vibrate meniscuses of liquid in the vicinity of nozzles

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP1974920B1Droplet ejection device
Publication Date: 2014.04.30 BROTHER KOGYO KK
  • EP1974920B1 patent drawingFigure 1
  • EP1974920B1 patent drawingFigure 2
  • EP1974920B1 patent drawingFigure 3

AI summary

A droplet ejection device includes: an ejection head having an actuator and a nozzle; an interface configured to receive data; and a controller configured to (a) execute, based on the received data, ejection control in which liquid droplets having respective different volumes are selectively ejected from the nozzle to a medium by driving the actuator and (b) execute recovery control in which ejection performance of the recording head is recovered by driving the actuator. The controller is configured to (c) determine, based on the received data, a volume of a droplet to be first ejected from the nozzle under the ejection control subsequent to the recovery control, and (d) set, based on the determined volume, a condition for driving the actuator to execute the recovery control.