Dynamic Ink Reservoir Pressure Control for 3D Printing

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Solution Overview

Problem

Conventional inkjet printing systems fail to dynamically manage backpressure effectively when printing on complex, three-dimensional surfaces, as the backpressure requirements change with the orientation of the printhead, leading to ink leakage or air intake issues.

Innovation Solution

An inkjet printing system with a rotatable ink reservoir and a control fluid system that adjusts pressure levels based on the orientation of the printhead, using a processor to calculate the desired pressure for maintaining a stable meniscus level in the nozzle, regardless of the printhead's orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If static backpressure is used in conventional inkjet systems, then the system structure is simple, but the system cannot adapt to changing orientation requirements when printing on three-dimensional surfaces

Engineering Contradiction:
Improveadaptability to different orientationsVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic backpressure control by replacing static pressure regulation with an active control system that continuously adjusts pressure based on printhead orientation. The control fluid source dynamically modulates pressure in response to orientation sensor feedback, enabling the system to adapt to varying gravitational effects at different angles while maintaining stable ink meniscus levels in the nozzle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback control through orientation sensors that detect the printhead's angular position and feed this information to the processor. The processor calculates the required backpressure adjustment based on the detected orientation and commands the control fluid source to make real-time pressure corrections, creating a closed-loop control system that continuously maintains optimal printing conditions

Inventive Principle:
Principle #23Feedback

2Reliability

If backpressure is increased to prevent ink leakage, then ink leakage is reduced, but air may be drawn into the printhead through the nozzle

Engineering Contradiction:
Improveink retention stabilityVSAvoidair intake risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the backpressure parameter based on printhead orientation angle. When the printhead is oriented vertically downward, higher backpressure is applied to prevent ink leakage. When the printhead tilts or orients upward, the backpressure is reduced to prevent air from being drawn into the nozzle through the ink meniscus. This continuous parameter adjustment maintains the ink meniscus in a stable state across all orientations

Inventive Principle:
Principle #35Parameter changes

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 system ensures consistent ink meniscus levels and prevents ink leakage or air intake by dynamically controlling backpressure, enabling reliable printing on complex surfaces.

Implementation Method 1

a control fluid source fluidly communicating with the control chamber to deliver a control fluid across a range of pressure levels

Methodology Applied
Scientific EffectPressure control: Pressure Gradient

Implementation Method 2

a flexible membrane disposed in the housing and dividing the interior chamber into a control chamber and an ink-receiving chamber

Methodology Applied
Scientific EffectPressure transmission through flexible membrane: Elasticity

Implementation Method 3

an orientation sensor for determining an orientation of the longitudinal axis of the ink reservoir and generate an orientation signal

Methodology Applied
Scientific EffectOrientation sensing: Accelerometer

Implementation Method 4

calculate an effective water column height along the vertical reference axis based on the inferred angle of the longitudinal axis and the distance D1, determine a desired pressure for the control chamber based, at least in part, on the effective water column height

Methodology Applied
Scientific EffectHydrostatic pressure calculation: Pascal's Law

Implementation Method 5

the nozzle defining a desired meniscus level having a fixed position relative to the ink reservoir, wherein ink disposed in the ink-receiving chamber defines an ink top surface level, and wherein the desired meniscus level of the nozzle is spaced from the ink top surface level along the longitudinal axis of the ink reservoir by a distance D1

Methodology Applied
Scientific EffectSurface tension at meniscus: Surface Tension

Data Source

PatentEP3415240B1Inkjet printing system having dynamically controlled ink reservoir and method of dynamically controlling the pressure in an ink reservoir
Publication Date: 2021.03.10 THE BOEING CO
  • EP3415240B1 patent drawingFigure 1~2
  • EP3415240B1 patent drawingFigure 3
  • EP3415240B1 patent drawingFigure 4

AI summary

An inkjet printing system includes an ink reservoir defining a longitudinal axis, an ink-receiving chamber and a control chamber. A control fluid source delivers a control fluid across a range of pressure levels to the control chamber, and an orientation sensor determines an orientation of the longitudinal axis of the ink reservoir and generates an orientation signal. A processor is operably coupled to the control fluid source and the orientation sensor, the processor being programmed to infer an angle of the longitudinal axis relative to the vertical reference axis based on the orientation signal from the orientation sensor, determine a desired pressure for the control chamber based, at least in part, on the inferred angle of the longitudinal axis, and control the control fluid source to adjust the actual pressure level in the control chamber to the desired pressure for the control chamber.