Micro-Fluid Ejection Head Adaptive Thermal Control

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Solution Overview

Problem

Current micro-fluid ejection devices face issues with thermal gradients across the ejector array, leading to non-uniform fluid droplet formation and print defects, as the edges tend to be cooler than the center, causing temperature control challenges during high-density swaths.

Innovation Solution

Implementing a zone-based temperature control system with separate heaters and sensors for the middle and edge zones of the micro-fluid ejection device substrate, where power is dynamically adjusted based on temperature set points to maintain optimal temperature ranges, ensuring uniform heating and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the entire ejector array is heated to a single predetermined temperature, then the heating system is simple, but thermal gradients cause non-uniform fluid droplet formation and print defects

Engineering Contradiction:

Improveheating system complexityVSAvoidfluid droplet formation uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The ejector array is divided into multiple zones (edge zones and middle zones) with separate heaters and temperature sensors for each zone. This segmentation allows independent temperature control of different regions, eliminating thermal gradients while maintaining manageable system complexity through modular zone-based architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each zone is equipped with its own heater and temperature sensor, enabling localized temperature control tailored to the specific thermal characteristics of that region. Edge zones receive different heating control than middle zones, allowing each area to maintain its optimal temperature for uniform fluid droplet formation.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If zone-based temperature control is implemented, then temperature uniformity improves, but the system complexity increases

Engineering Contradiction:

Improvetemperature uniformityVSAvoidtemperature control system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system is segmented into discrete zones with dedicated heaters and sensors, making the complex temperature control problem manageable through modular units. Each zone operates independently, simplifying the control logic while achieving overall temperature uniformity across the ejector array.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If high heating power is applied to maintain edge temperature, then temperature uniformity improves, but the ejector array temperature rises above target causing loss of control

Engineering Contradiction:

Improvetemperature uniformityVSAvoidejector array temperature control

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

Edge zones and middle zones have different heating requirements and are controlled independently. Edge zones receive targeted heating to compensate for their natural cooling, while middle zones maintain their temperature without excessive heating, preventing the overall array temperature from rising above the target level.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Each zone has its own temperature sensor providing real-time feedback to the control system. This feedback mechanism allows the system to adjust heating power dynamically, applying just enough heat to maintain temperature uniformity without causing the ejector array to overshoot the target temperature.

Inventive Principle:

Principle #23Feedback

4Device complexity

If natural heat dissipation is relied upon, then the system is simple, but edge zones become cooler than middle zones creating thermal gradients

Engineering Contradiction:

Improveheat management systemVSAvoidedge zone temperature

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The heating system is segmented by zone, with separate heaters for edge and middle zones. This allows edge zones to receive targeted heating to compensate for natural heat dissipation, maintaining temperature uniformity without requiring a complex overall heat management system.

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 maintains uniform fluid droplet formation by keeping the edge and middle zones within specified temperature ranges, preventing print defects and ensuring consistent performance during high-density swaths.

Implementation Method 1

The fluid ejection actuators in the ejection chambers impart energy to the fluid that is sufficient to induce the fluid to form a vapor bubble that propels the fluid from the ejection chamber through the nozzle and onto the fluid receiving medium. The element that imparts the energy to the fluid within the ejection chambers may take the form of a resistive heater

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Implementation Method 2

Methodology Applied

Scientific EffectVapor bubble formation: Phase Change

Data Source

PatentUS7614715B2Micro-fluid ejection head having adaptive thermal control

Publication Date: 2009.11.10 BRADY WORLDWIDE INC

AI summary

A method of controlling a micro fluid ejection device by sensing a middle zone temperature, and selectively applying an amount of power to a middle zone heater to achieve a target temperature. An edge zone temperature is also sensed and power is selectively applied to edge zone heaters to achieve a target temperature for the edge zones, whereby uniform ejection of fluid droplets along an ejector array may be achieved.