Air Purging Unit for Printhead Protection

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Solution Overview

Problem

Off-axis imaging devices face issues with air entering the fluid delivery tubes during startup, which can affect the performance and lifespan of the printhead, as they are typically shipped with empty fluid storage chambers and uninstalled cartridges, leading to air being introduced into the system before printing fluid is filled.

Innovation Solution

An air purging unit is coupled to the imaging device's housing before cartridge installation, which purges air from the fluid delivery tubes after filling the printing fluid in the storage chambers, ensuring that only fluid reaches the cartridges, thus preventing air from entering the printhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the imaging device is shipped with empty fluid storage chambers and uninstalled cartridges, then the device can be transported and stored efficiently, but air enters the fluid delivery tubes during startup which affects printhead performance and lifespan

Engineering Contradiction:
Improveprinthead performance and lifespanVSAvoidair entering fluid delivery tubes
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by purging air from the fluid delivery tubes before cartridges are installed and before printing operations begin. The system includes a purging mechanism that removes air from the fluid delivery path during the startup phase, ensuring that only printing fluid flows to the cartridges when they are subsequently installed, thereby preventing air from reaching and damaging the printhead.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary purging mechanism between the fluid storage chamber and the cartridge/printhead assembly. This intermediary system captures and removes air from the fluid delivery tubes before the fluid reaches the sensitive printhead components, acting as a protective barrier that prevents direct harm from air entrapment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If cartridges are installed immediately without purging, then the device can start operating quickly, but air in the fluid delivery tubes causes performance issues and reduces printhead lifespan

Engineering Contradiction:
Improvestartup speedVSAvoidprinthead lifespan
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs air purging as a preliminary action during the startup sequence, before printing operations commence. The purging mechanism is activated automatically when the device is powered on, removing air from the fluid delivery tubes in advance, so that cartridge installation and printing can proceed without air-related interruptions or damage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a rapid purging process that quickly removes air from the fluid delivery tubes during startup. The system is designed to purge air efficiently and rapidly, minimizing the time required for this preparatory step, allowing the device to transition quickly from startup to operational state while still ensuring complete air removal to protect the printhead.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentEP3787903B1Air purging
Publication Date: 2024.02.21 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3787903B1 patent drawingFigure 1
  • EP3787903B1 patent drawingFigure 2
  • EP3787903B1 patent drawingFigure 3

AI summary

Examples of air purging from a fluid delivery tube of an imaging device are described. In an example, air is removed from the fluid delivery tube by an air purging unit prior to coupling a cartridge in the imaging device.