Enclosed Cross-Channels for Fluidic Ejection Die Cooling

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Solution Overview

Problem

Fluidic ejection devices face issues with sedimentation of particles, leading to blocked nozzles and reduced print quality, and the accumulation of waste heat due to micro-recirculation pumps, which depletes fluid and negatively impacts nozzle performance.

Innovation Solution

The implementation of enclosed cross-channels on the backside of the fluidic ejection die to enhance fluid flow and replenish the micro-recirculation loop with fresh fluid, combined with embedding the die in a moldable material for improved integration and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If micro-recirculation pumps are used to prevent particle sedimentation, then nozzle blockage is reduced, but waste heat accumulates and fluid is depleted

Engineering Contradiction:
Improvenozzle blockage preventionVSAvoidwaste heat accumulation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the harmful waste heat from the recirculation system by introducing a separate waste heat removal path. The cross-channels provide a dedicated flow path that allows heat to be carried away from the recirculation loop, separating the particle prevention function from the heat accumulation problem.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cross-channels act as an intermediary structure that mediates between the recirculation pumps and the fluid supply system. They provide a transition path that allows fresh fluid to enter the recirculation loop while enabling heat to be removed, thus mediating between particle prevention and heat management requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If cross-channels are added to replenish fluid flow, then water concentration is maintained, but device complexity increases

Engineering Contradiction:
Improvewater concentrationVSAvoidchannel structure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent merges the cross-channels with the existing substrate structure, integrating the fluid replenishment function into the base substrate rather than adding separate components. The cross-channels are formed as part of the substrate itself, combining structural support and fluid transport functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cross-channels serve multiple functions: they replenish fluid to maintain water concentration, remove waste heat through convective flow, and provide a path for fresh fluid to enter the recirculation system. This multi-functionality reduces the need for separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If enclosed cross-channels are formed on the backside of the die, then manufacturing precision is improved, but ease of manufacture decreases

Engineering Contradiction:
Improvechannel alignment precisionVSAvoidsubstrate fabrication difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical assembly of separate channel components with direct formation of channels in the substrate using deposition and etching processes. This substitution of mechanical manufacturing with semiconductor fabrication techniques enables precise channel formation while maintaining ease of manufacture through standardized processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution maintains water concentration, enhances micro-recirculation efficiency, improves nozzle health, increases print quality, convectively cools the die, removes air bubbles, and allows for re-priming of nozzles, thereby addressing the issues of sedimentation and waste heat accumulation.

Implementation Method 1

An array of enclosed cross-channels is formed on a backside of the substrate. Each enclosed cross-channel of the array of enclosed cross-channels is fluidly connected to a respective plurality of passages of the array of passages... Fluid is supplied to the array of passages through the inlet and exits the array of passages through the outlet

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

The fluidic ejection die also includes an array of micro-recirculation loops... Each micro-recirculation loop of the array of micro-recirculation loops is fluidly connected to a respective passage of the array of passages

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 3

embedding the die in a moldable material for improved integration and cooling... convectively cools the die

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

embedding the die in a moldable material for improved integration and cooling... removes air bubbles, and allows for re-priming of nozzles

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3609712B1Fluidic ejection devices with enclosed cross-channels
Publication Date: 2023.11.29 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3609712B1 patent drawingFigure 1A
  • EP3609712B1 patent drawingFigure 1B
  • EP3609712B1 patent drawingFigure 2A~2D

AI summary

In one example in accordance with the present disclosure, a fluidic ejection device is described. The device includes a fluidic ejection die embedded in a moldable material. The die includes an array of nozzles. Each nozzle includes an ejection chamber and an opening. A fluid actuator is disposed within the ejection chamber. The fluidic ejection die also includes an array of passages, formed in a substrate, to deliver fluid to and from the ejection chamber. The fluidic ejection die also includes an array of enclosed cross-channels. Each enclosed cross-channel of the array of enclosed cross-channels is fluidly connected to a respective plurality of passages of the array of passages. The device also includes the moldable material which includes supply slots to deliver fluid to and from the fluidic ejection die. A carrier substrate of the device supports the fluidic ejection die and moldable material.