Printhead Obturator Alignment for Leak-Free Nozzle Closure

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Solution Overview

Problem

Conventional ink-jet printheads face issues with precision assembly and manufacturing tolerances, leading to fluid leakage and compromised print quality due to incorrect alignment of obturator components, which is costly and complex to achieve with existing micro-machining and assembly techniques.

Innovation Solution

An obturator device with a spherical structure and adhesive fixing means, coupled with a piezoelectric actuator and elastomeric springs, ensures precise alignment and repeated coplanarity of the valve surface with the nozzle surface, compensating for manufacturing and assembly tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional micro-machining and assembly techniques are used to fabricate and assemble obturator components, then manufacturing precision can be achieved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvealignment precision of obturator valve surface with nozzle surfaceVSAvoidnumber of components and assembly steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the obturator assembly and nozzle portion into a single integrated component structure. The obturator valve surface and nozzle bearing surface are formed as integral parts of the same component, eliminating the need for separate fabrication and precise assembly of multiple parts. This integration directly resolves the contradiction by achieving manufacturing precision without increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If high pressure is applied to force the obturator into contact with the nozzle portion, then closure reliability improves, but wear on surfaces increases and drive voltage requirement increases

Engineering Contradiction:
Improvenozzle closure reliabilityVSAvoidsurface wear and energy consumption
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the valve surface and bearing surface to achieve optimal contact. By designing the valve surface with a shaped structure that complements the bearing surface geometry, the obturator achieves reliable nozzle closure at lower pressures. This reduces surface wear and decreases the drive voltage required actuator operation, resolving the contradiction between reliability and harmful effects.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple components with μm dimensions are used to achieve precise alignment, then manufacturing precision improves, but assembly difficulty and cost increase

Engineering Contradiction:
Improvecoplanarity of valve surface with bearing surfaceVSAvoidassembly simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent combines multiple precision components into a single integrated obturator assembly where the valve surface and connecting elements are formed as one piece. This eliminates the need for complex multi-component assembly procedures while maintaining the required coplanarity and alignment precision, directly addressing the contradiction between manufacturing precision and ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

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 obturator device achieves precise and repeatable alignment of the valve surface with the nozzle surface, enhancing the operational performance and print quality by preventing fluid leakage and maintaining optimal droplet ejection control.

Implementation Method 1

an actuator in the form of a piezoelectric element 106 having an obturator 107 coupled thereto

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the adhesive material is arranged between the connecting element and valve element

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3027415B1An improved obturator and method of fabrication thereof
Publication Date: 2021.01.20 I C SRL
  • EP3027415B1 patent drawingFigure 1
  • EP3027415B1 patent drawingFigure 2
  • EP3027415B1 patent drawingFigure 3

AI summary

An obturator device (1) for a printhead comprising: an obturator assembly (3) having a valve surface (6) movable along at least one direction of displacement (X) between a first position in which the valve surface (6) is at a distance from a reference surface (A)and a second position in which the valve surface (6) is in contact with the reference surface (A); an actuator (2), secured to the obturator assembly (3) and operable to displace the obturator assembly (3) between the first position and second position; characterized in that the obturator assembly (3) comprises: an adjustable coupling (11) configured to allow the valve surface (6) to align its orientation relative to the reference surface (A)thereby ensuring improved engagement between the surfaces.