Fluidic Die Segmented Recirculation for Nozzle Clogging

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Solution Overview

Problem

Pigment settling in printable fluids leads to clogging of nozzles in fluid ejection dies, resulting in suboptimal printing performance and increased waste heat from micro-recirculation pumps, which limits the effectiveness of micro-recirculation in preventing nozzle capping and maintaining low operating temperatures.

Innovation Solution

A fluidic die design with a carrier substrate, interposer layer, and microfluidic pumps that includes a system for recirculating fluid through a fluid reservoir, with a fluid channel layer and interposer layer optimized for uniform fluid flow, and overmolded with a moldable material to manage temperature and fluid distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If micro-recirculation pumps are used to prevent pigment settling and nozzle clogging, then nozzle health is improved, but waste heat increases and operating temperature rises

Engineering Contradiction:
Improvenozzle healthVSAvoidoperating temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The fluid delivery system is segmented into multiple independent fluid channels, each serving specific nozzle groups. This segmentation allows selective recirculation of fluid through specific channels using dedicated micro-recirculation pumps, enabling localized pigment resuspension without requiring system-wide recirculation that would generate excessive waste heat throughout the entire die structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the fluid delivery system are treated differently: fluid channels near the nozzle array receive enhanced recirculation flow to prevent pigment settling, while other channels maintain standard flow patterns. This local quality approach concentrates the heat-generating recirculation activity only where needed for nozzle health, minimizing overall temperature rise.

Inventive Principle:
Principle #3Local quality

2Reliability

If micro-recirculation is enhanced to prevent nozzle capping, then printing performance is improved, but thermal defects increase

Engineering Contradiction:
Improveprinting performanceVSAvoidthermal defects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A dedicated recirculation fluid channel acts as an intermediary pathway between the fluid reservoir and the nozzle array. This intermediate channel allows fluid to be recirculated through a controlled path with dedicated pumping, separating the recirculation function from the primary ejection channels and enabling better thermal management by isolating the heat-generating recirculation flow in a dedicated pathway.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If fluid is recirculated through the die to prevent pigment settling, then nozzle clogging is reduced, but energy consumption increases

Engineering Contradiction:
Improvenozzle clogging preventionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of recirculating fluid through the entire die structure continuously, the system applies partial recirculation action by using multiple small-diameter micro-recirculation channels that only serve specific nozzle groups. This partial action approach recirculates fluid only where pigment settling is detected or anticipated, reducing total energy consumption compared to system-wide recirculation while still effectively preventing nozzle clogging.

Inventive Principle:
Principle #16Partial or excessive action

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 reduces the likelihood of nozzle capping, enhances micro-recirculation efficiency, improves nozzle health, and convectively cools the fluid ejection die, maintaining print quality and reducing thermal defects.

Implementation Method 1

The fluid ejection die may include resistive or piezoelectric elements used to cause fluid to be ejected from the fluid ejection die

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

The fluid ejection die may include resistive or piezoelectric elements used to cause fluid to be ejected from the fluid ejection die

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

convectively cools the fluid ejection die

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3634760B1Fluidic dies
Publication Date: 2023.10.25 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3634760B1 patent drawingFigure 1A~1C
  • EP3634760B1 patent drawingFigure 2
  • EP3634760B1 patent drawingFigure 3

AI summary

A fluidic die includes a fluid channel layer including at least one fluid channel defined along a length of the fluid ejection device. The fluidic die also includes an interposer layer coupled to the fluid channel layer. The interposer layer includes a number of inlet ports defined in the interposer layer to fluidically couple the at least one channel layer to a fluid source, and a number of outlet ports defined in the interposer layer to fluidically couple the at least one channel layer to the fluid source.