Fluid Ejection Apparatus Recirculation Channel Filter

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Solution Overview

Problem

Fluid ejection devices, such as printers, face performance issues due to entrapment of contaminating particles and air bubbles, which affect the reliability and quality of printing.

Innovation Solution

A fluid ejection apparatus with a fluid slot, recirculation channel, drop generator, fluid circulation pump, and filter is designed to circulate fluid across the drop generator, filter, and pump, ensuring that fluid is replenished and contaminants are removed before each droplet ejection, reducing nozzle failures and enhancing printing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluid is circulated through a recirculation channel with a filter and pump, then contamination and air bubble entrapment are reduced, but device complexity increases

Engineering Contradiction:
Improveprinting performance reliabilityVSAvoidfluid circulation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The recirculation channel integrates multiple functions into a single continuous fluid pathway: fluid ejection, filtration, pumping, and circulation are merged into one unified system. The channel connects the fluid slot, filter, and pump in sequence, allowing the same fluid to be repeatedly circulated through all components without requiring separate systems for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter is positioned in the recirculation channel to remove contaminants and air bubbles from the fluid before the fluid reaches the drop generator for ejection. This preliminary filtration action prevents contamination issues during the actual printing process, addressing potential problems before they occur.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If fluid is continuously circulated and filtered, then contaminant introduction is reduced, but loss of time for fluid circulation increases

Engineering Contradiction:
Improvenozzle failure resistanceVSAvoidfluid circulation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The recirculation system operates continuously, maintaining constant fluid circulation through the channel, filter, and pump. This continuous circulation ensures that fluid is constantly being purified and replenished, preventing contaminant accumulation and air bubble entrapment without requiring periodic interruptions for maintenance or priming.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system automatically circulates and filters fluid without external intervention. The pump continuously draws fluid through the filter and returns it to the fluid slot, creating a self-sustaining circulation loop that maintains fluid purity and prevents contamination issues without requiring manual operation.

Inventive Principle:
Principle #25Self-service

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 apparatus effectively reduces the introduction of external contaminants and air bubbles, leading to improved printing performance by ensuring that fluid is purified and circulated before each droplet is ejected, thereby enhancing the reliability and quality of the printing process.

Implementation Method 1

A piezoelectric fluid actuator is located in a channel to cause fluid to flow from a fluid slot, through the channel and a drop generator

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2828088B1Fluid ejection apparatus
Publication Date: 2020.05.27 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2828088B1 patent drawingFigure 1~3
  • EP2828088B1 patent drawingFigure 4
  • EP2828088B1 patent drawingFigure 5~7

AI summary

A fluid ejection apparatus (20, 220, 320, 420, 520, 620, 720, 820, 920, 1020, 1120, 1220, 1320, 1420, 1490, 1720, 1820) and method eject a droplet of fluid using a drop generator (46, 246, 1546) receiving fluid from a passage (44, 244, 1344, 1444, 1494, 1544, 1744) having an inlet (54, 254, 1554) adjacent a fluid slot (40, 240, 1540) and an outlet (56, 256, 1556) spaced from the inlet (54, 254, 1554) and adjacent the fluid slot (40, 240, 1540). Fluid is drawn through a filter (50, 250, 650, 1550) with a pump (48, 248, 1548) within the passage (44, 244, 1344, 1444, 1494, 1544, 1744) that pumps the fluid towards the inlet (54, 254, 1554) to the drop generator (46, 246, 1546).