Continuous Inkjet Printer Speed Control for Print Quality

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Solution Overview

Problem

Continuous inkjet printers face challenges in maintaining print quality at maximum speed due to elongation of printed images caused by increased production line speed, leading to unnecessary alerts and potential overload of software systems.

Innovation Solution

A method that allows users to define an allowable amount of stretch in the print direction, using a speed sensing facility to compare target gaps between strokes with actual gaps, and generating alerts only when the actual stretch exceeds this limit, thereby providing a more controlled and meaningful warning of print quality degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the production line speed is increased to maximize productivity, then the print speed capability is improved, but the print quality deteriorates due to elongation of printed images

Engineering Contradiction:
Improveprint speed capabilityVSAvoidprint quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the stroke timing based on real-time substrate speed measurements. The time-of-flight system continuously calculates the actual speed of the substrate and modifies the stroke onset timing accordingly, allowing the printer to maintain print quality across varying production line speeds without being constrained by a fixed maximum speed limit

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the timing parameter of stroke execution based on measured substrate speed. By continuously monitoring substrate speed and adjusting the stroke onset timing parameter in real-time, the system compensates for speed variations and prevents image elongation, enabling high productivity while maintaining print quality

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If traditional stretch detection is used to monitor print quality, then print quality monitoring is improved, but software system complexity increases due to unnecessary alerts and potential overload

Engineering Contradiction:
Improveprint quality monitoringVSAvoidsoftware system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses feedback from the time-of-flight measurement to proactively adjust stroke timing before quality degradation occurs. By continuously measuring substrate speed and adjusting timing in real-time, the system prevents stretch from occurring in the first place, eliminating the need for complex post-processing alert systems and quality control software

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system takes preliminary action by adjusting stroke timing based on predicted substrate position. The time-of-flight system calculates where the substrate will be when each stroke should occur and pre-adjusts the timing accordingly, preventing quality issues before they happen rather than detecting and responding to them after the fact

Inventive Principle:
Principle #10Preliminary action

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 approach reduces unnecessary alerts and allows users to manage print quality effectively by specifying an acceptable level of elongation, enabling better decision-making and minimizing software overload while maintaining high print speeds.

Implementation Method 1

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

Methodology Applied
Scientific EffectElectrostatic deflection: Electrostatics

Implementation Method 2

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

Methodology Applied
Scientific EffectElectrical charging: Electrostatics

Implementation Method 3

Ink, together with entrained air, is generally returned to the printer housing under vacuum, the vacuum being generated by a pump in the gutter line

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Data Source

PatentEP3619046B1Improvements in or relating to printers
Publication Date: 2022.06.22 DOMINO UK
  • EP3619046B1 patent drawingFigure 1
  • EP3619046B1 patent drawingFigure 2
  • EP3619046B1 patent drawingFigure 3A~3C

AI summary

A printer (5) operable to print a message in strokes on a substrate (7) passing in a print direction (8) along a moving line (6), wherein the printer is operable (15) to receive an indication of an allowable increase in length in the print direction of a message due to an increase in length in the print direction of gaps between successive strokes printed by the printer, to receive (14) an indication (9) of a speed of movement in the print direction of a moving line, to determine from the indication of the speed of movement of the moving line whether an increase in length in the print direction of a message printed by the printer is greater than the allowable increase in length and, if so, to generate an alert,