Liquid Jetting Apparatus Nozzle Flushing Control

Solution Overview

Problem

In liquid jetting apparatuses, such as ink-jet printers, the viscosity of ink in nozzles increases over time due to drying, leading to potential jetting defects like non-jetting, especially in outer-side nozzles which dry faster than inner-side nozzles due to environmental humidity and airflow differences.

Innovation Solution

A liquid jetting apparatus with a controller that determines a basic flushing amount for each nozzle and adjusts the flushing amount based on the nozzle's position, with inner-side nozzles receiving the basic amount and outer-side nozzles receiving a larger amount to ensure reliable discharge of thickened ink, thereby preventing unnecessary ink discharge and minimizing waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flushing is performed with a basic amount for all nozzles, then inner-side nozzles are adequately flushed, but outer-side nozzles suffer from insufficient flushing due to faster thickening

Engineering Contradiction:

Improveflushing effectivenessVSAvoidjetting performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating the flushing amount based on nozzle position. Outer-side nozzles receive a larger flushing amount than inner-side nozzles, matching the localized thickening characteristics of each region. This ensures that each nozzle receives the appropriate flushing intensity for its specific environmental conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the nozzle array into inner-side nozzles and outer-side nozzles based on their positional characteristics. This segmentation allows the control unit to apply different flushing strategies to different groups, addressing the varying thickening rates caused by differences in environmental exposure.

Inventive Principle:

Principle #1Segmentation

2Reliability

If flushing amount is increased for all nozzles to ensure outer-side nozzles are adequately flushed, then outer-side nozzles are properly cleared, but unnecessary ink is discharged from inner-side nozzles increasing waste

Engineering Contradiction:

Improvedischarge assuranceVSAvoidink waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements local quality by assigning different flushing amounts to different nozzle groups. Inner-side nozzles receive a basic flushing amount appropriate for their lower thickening rate, while outer-side nozzles receive an increased flushing amount to compensate for their higher thickening rate. This localized approach minimizes overall ink waste while ensuring adequate clearing of all nozzles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies partial action by providing excessive flushing only where needed (outer-side nozzles) rather than uniformly to all nozzles. This selective excessive action ensures reliable discharge from problematic outer-side nozzles without subjecting inner-side nozzles to unnecessary additional flushing that would increase waste.

Inventive Principle:

Principle #16Partial or excessive action

3Device complexity

If uniform flushing is applied to all nozzles, then the control system is simple, but temperature differences between inner and outer nozzle regions are not compensated

Engineering Contradiction:

Improvecontrol complexityVSAvoidtemperature uniformity

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The patent applies local quality by differentiating the flushing amount based on nozzle position. Outer-side nozzles receive a larger flushing amount than inner-side nozzles, matching the localized thickening characteristics of each region. This ensures that each nozzle receives the appropriate flushing intensity for its specific environmental conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the nozzle array into inner-side nozzles and outer-side nozzles based on their positional characteristics. This segmentation allows the control unit to apply different flushing strategies to different groups, addressing the varying thickening rates caused by differences in environmental exposure.

Inventive Principle:

Principle #1Segmentation

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 ensures assured discharge of thickened ink from outer-side nozzles while minimizing ink wastage and reducing temperature differences between inner and outer nozzle regions, maintaining printing efficiency and quality.

Implementation Method 1

a pressure generating element configured to generate pressure for jetting the liquid from the plurality of nozzles toward the medium

Methodology Applied

Scientific EffectPressure generation: Pressure Increase

Implementation Method 2

a viscosity of the liquid inside the nozzle increases due to drying

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS9061504B2Liquid jetting apparatus

Publication Date: 2015.06.23 BROTHER KOGYO KK

AI summary

There is provided a liquid jetting apparatus including: a liquid jetting head including a pressure generating element and a plurality of nozzles arranged in rows in a nozzle-row direction; and a controller. The controller is configured to: determine a basic flushing amount for each nozzle; make the liquid jetting head carry out flushing with the basic flushing amount for inner-side nozzles positioned at an inner side in the nozzle-row direction; and make the liquid jetting head carry out flushing with a flushing amount larger than the basic flushing amount, for outer-side nozzles positioned at an outer side in the nozzle-row direction, of the inner-side nozzles.