Cross-Die Recirculation Channels for Print Quality

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Solution Overview

Problem

In fluid ejection devices, such as printing devices, the settling of solids like pigments within the fluid chambers and channels of the die can lead to fluid ejection defects, resulting in uneven print quality due to a higher concentration of liquid carrier being ejected than solids.

Innovation Solution

The implementation of cross-die recirculation channels and chamber recirculation channels within the die, coupled with pumps, to recirculate the printing fluid and prevent the settling of solids, ensuring a consistent mixture of pigments and liquid carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If printing fluid is circulated through the die, then solid settlement is prevented and print quality is improved, but device complexity increases due to additional recirculation channels and pumps

Engineering Contradiction:
Improveprint quality consistencyVSAvoidrecirculation system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the die structure itself. The recirculation channels are integrated directly into the die, and the pump is formed within the chamber recirculation channel. This merging of circulation functionality into the existing die structure achieves solid suspension and print quality improvement without adding separate external circulation systems, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The die structure serves multiple functions: it acts as both the ejection component and the recirculation system housing. The cross-die recirculation channels and chamber recirculation channels are formed into the die itself, allowing the die to simultaneously perform fluid ejection and fluid recirculation with solid suspension, reducing the need for additional dedicated circulation components.

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

2Stability of the object's composition

If recirculation channels are formed into the die, then solid distribution is maintained, but manufacturing complexity increases

Engineering Contradiction:
Improvesolid distribution uniformityVSAvoiddie fabrication process
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent utilizes fluid dynamics principles to achieve solid suspension and distribution. The recirculation channels are designed to circulate printing fluid through the die, using hydrodynamic forces to prevent solid settlement. This hydraulic approach maintains uniform solid distribution while the channels are formed using standard semiconductor fabrication techniques, balancing manufacturing feasibility with functional performance.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If pumps are integrated into the recirculation channels, then fluid circulation is achieved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvefluid circulation efficiencyVSAvoidintegrated pump structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pump is nested within the chamber recirculation channel, which itself is formed into the die. This nested structure allows the pump to be integrated into the recirculation system without requiring separate housing or external mounting. The pump, channels, and die structure are hierarchically integrated, achieving efficient fluid circulation while minimizing the increase in overall device complexity through space-efficient nesting.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 recirculation system effectively maintains the uniform distribution of solids within the fluid, enhancing print quality by preventing the separation of pigments from the liquid carrier, thus ensuring consistent and high-quality prints.

Implementation Method 1

at least one pump formed within the chamber recirculation channel to recirculate the amount of printing fluid therethrough

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

recirculate the printing fluid and prevent the settling of solids, ensuring a consistent mixture of pigments and liquid carrier

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3717258B1Cross-die recirculation channels and chamber recirculation channels
Publication Date: 2025.04.30 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3717258B1 patent drawingFigure 1
  • EP3717258B1 patent drawingFigure 2
  • EP3717258B1 patent drawingFigure 3

AI summary

A die may, in an example, include at least one cross-die recirculation channel formed into the die to recirculate an amount of printing fluid therethrough, the cross-die recirculation channel including a first-sized inlet port and a first-sized outlet port formed on a first side of the die, at least one chamber recirculation channel formed into the die and fluidically coupled to the cross-die recirculation channel to recirculate an amount of printing fluid therethrough, the chamber recirculation channel including a second-sized inlet port and a second-sized outlet port, at least one pump formed within the chamber recirculation channel to recirculate the amount of printing fluid therethrough.