Printing Fluid Pen Circulation via Pressure Regulator and Valve

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Printing fluid circulation within fluid ejection devices is challenging due to issues like solid settlement, increased viscosity, and backpressure, which can lead to decreased fluid flux and undesirable print quality, especially when trying to maintain fluid circulation during active ejection.

Innovation Solution

A system with a pressure regulator and a valve that allows fluid circulation by opening in response to negative pressure, enabling fluid to exit while maintaining operational flux levels, comprising a printing fluid pen with multiple fluid ports and a pressure regulator in communication with the input port and a valve at the output port.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluid circulation is implemented to prevent solid settlement and maintain print quality, then printing fluid can be kept suspended and thermal buildup dissipated, but fluid flux decreases due to backpressure and circulation requirements

Engineering Contradiction:
Improveprint quality consistencyVSAvoidfluid flux
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The fluid delivery system is segmented into multiple independent paths: a first path for ejection and a second path for circulation. This allows the ejection function to maintain high flux while the circulation path handles backpressure and solid suspension separately, resolving the contradiction between maintaining fluid flux and ensuring print quality consistency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A pressure regulator is introduced as an intermediary component between the fluid reservoir and the ejection device. The pressure regulator manages backpressure and ensures smooth fluid flow, enabling circulation without significantly reducing the flux available for ejection, thus maintaining both productivity and print quality

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If pressure regulator is added to manage backpressure and enable circulation, then fluid flow is improved, but device complexity increases

Engineering Contradiction:
Improvefluid flow managementVSAvoidsystem structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pressure regulator serves multiple functions simultaneously: it manages backpressure, enables fluid circulation, and maintains smooth flow. By consolidating these functions into a single component, the system achieves improved fluid flow management without proportionally increasing device complexity

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

Solution Approach 2:

The circulation function is extracted from the main ejection path and placed in a separate parallel path. This allows the pressure regulator to be positioned strategically to manage circulation independently, simplifying the overall system architecture while improving ease of operation

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables fluid circulation within the pen during active ejection without drops in fluid flux, ensuring consistent print quality by managing backpressure and maintaining fluid flow through the system.

Implementation Method 1

the valve is to open in response to a negative pressure, to enable fluids within the pen to circulate and exit via the second fluid port

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

A pressure regulator may be used maintain pressure on a printing fluid in a fluid line in a range about a set point

Methodology Applied
Scientific EffectPressure regulation: Pressure Gradient

Data Source

PatentEP4003739B1Printing fluid circulation
Publication Date: 2025.01.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP4003739B1 patent drawingFigure 1~2B
  • EP4003739B1 patent drawingFigure 3A~3B
  • EP4003739B1 patent drawingFigure 4

AI summary

An example printing fluid pen comprises a plurality of fluid ports, a pressure regulator in fluid communication with a first fluid port, and a valve in fluid communication with a second fluid port. The first fluid port is to deliver printing fluid to a fluid ejection device, and the second fluid port to direct printing fluid out of the pen. In response to negative pressure, the valve is to open to enable fluids within the pen to exit via the second port.