FPGA Phase Testing for Continuous Inkjet Printers

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Solution Overview

Problem

Continuous inkjet printers face challenges in synchronizing the charging of ink droplets at high speeds due to the need for phase testing, which requires a finite time and can compromise print quality on fast production lines with closely spaced products.

Innovation Solution

Incorporating a field-programmable gate array (FPGA) to control the switching of amplifiers and initiate phase tests based on a system clock, allowing for reduced inter-message gaps by eliminating the need for capacitor discharge and optimizing the phase testing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phase testing is performed to synchronize droplet charging at high speeds, then charge synchronization accuracy is improved, but the time required for phase testing increases the inter-message gap between successive prints

Engineering Contradiction:
Improvecharge synchronization accuracyVSAvoidinter-message gap time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs phase testing during the inter-message gap period between successive prints, rather than requiring a separate dedicated time period. The system uses the otherwise idle time between printing operations to conduct phase measurements and adjustments, thereby preparing the system in advance for the next print operation without extending the overall cycle time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic phase testing at predetermined intervals during the printing operation, rather than requiring continuous or extensive phase testing before each print. This periodic approach maintains adequate synchronization accuracy while minimizing the time consumed by phase testing activities.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If the system waits for capacitor discharge before phase testing, then measurement accuracy is improved, but the recovery period extends the inter-message gap

Engineering Contradiction:
Improvephase testing measurement accuracyVSAvoidrecovery period time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent maintains continuous operation by performing phase testing during the inter-message gap when the system is otherwise idle. Rather than stopping or waiting for capacitor discharge, the system continuously utilizes available time periods for productive phase measurement activities, eliminating wasted recovery periods.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent rushes through the phase testing process by utilizing the brief inter-message gap period efficiently. The system performs necessary phase measurements and adjustments quickly during the available time, rather than allowing the system to slow down or wait for capacitor discharge cycles.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 solution enables faster and more efficient phase testing, reducing the time between prints while maintaining accurate charge synchronization, thereby improving print quality on high-speed production lines.

Implementation Method 1

a vibration or perturbation is applied to the ink jet causing the jet to break into a stream of droplets

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

the printer includes a charge electrode to charge selected droplets, and an electrostatic facility to deflect the charged droplets

Methodology Applied
Scientific EffectElectrostatics: Electrostatics

Implementation Method 3

an electrostatic facility to deflect the charged droplets away from their original trajectory and onto a substrate

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentEP3526047B1Improvements in or relating to continuous inkjet printers
Publication Date: 2021.05.05 DOMINO UK
  • EP3526047B1 patent drawingFigure 1
  • EP3526047B1 patent drawingFigure 2A~2B
  • EP3526047B1 patent drawingFigure 3~4

AI summary

The invention describes a number of methods and apparatus for shortening the inter-message gap on a continuous inkjet printer. Included is a novel phase testing methodology.