Pivoting Printhead Testing for Sheet Workpiece Printing

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Solution Overview

Problem

Existing inkjet printing systems on an industrial scale face inefficiencies in nozzle cleaning and functionality assessment, particularly when printing on sheet-shaped workpieces, as test prints on these workpieces are costly and impractical, and the thickness variation of workpieces complicates full functionality assessment.

Innovation Solution

A printing device with a pivoting printhead and integrated control unit, allowing for independent nozzle testing and cleaning on a recording medium, such as paper, using a detection unit for software-based analysis, and a cleaning unit with movable components for maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If test prints are performed on sheet-shaped workpieces to check nozzle functionality, then nozzle functionality can be assessed, but printing costs increase significantly and workpiece consumption increases

Engineering Contradiction:
Improvenozzle functionalityVSAvoidworkpiece consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent introduces a scanning mechanism that creates a digital copy (scan image) of the workpiece surface after printing. This digital copy is then evaluated to assess nozzle functionality, eliminating the need to consume physical workpieces for testing. The scanning process captures printed patterns that reveal nozzle status without requiring additional material consumption.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces manual visual inspection with an automated scanning and digital evaluation system. Instead of physically examining printed workpieces or using traditional test print methods that consume materials, the system uses optical scanning and digital image processing to assess nozzle functionality, reducing both material consumption and operational costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If test prints are performed on workpieces with varying thicknesses to assess full functionality, then complete nozzle functionality can be verified, but suitable workpieces of maximum thickness must be available which increases complexity

Engineering Contradiction:
Improveprinting device functionalityVSAvoidworkpiece requirement management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The scanning mechanism creates a digital representation of the printed workpiece, allowing functional assessment independent of the physical workpiece dimensions. The digital copy captures all printed patterns and can be evaluated to determine nozzle functionality without requiring workpieces of maximum thickness or specific dimensions.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent segments the workpiece evaluation process into separate functional assessments. Instead of requiring a single comprehensive test print on maximum thickness workpieces, the system can evaluate different nozzle functions independently through scanning, allowing testing with standard thickness workpieces that are more readily available.

Inventive Principle:
Principle #1Segmentation

3Reliability

If manual cleaning of printheads is performed to ensure nozzle functionality, then printing quality can be maintained, but time consumption and labor requirements increase

Engineering Contradiction:
Improveprinting qualityVSAvoidcleaning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The scanning and digital evaluation system provides immediate feedback on printing quality and nozzle functionality. By continuously monitoring printed patterns through scanning, the system can detect when cleaning is needed and assess the effectiveness of cleaning operations, enabling timely maintenance that minimizes production interruptions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual cleaning operations with automated scanning and digital analysis systems. The scanning mechanism automatically detects printing issues and can trigger automated cleaning cycles, reducing the time and labor required for maintenance while ensuring consistent printing quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4422873B1Printing device for printing a workpiece and method
Publication Date: 2025.12.03 HOMAG GMBH
  • EP4422873B1 patent drawingFigure 1
  • EP4422873B1 patent drawingFigure 2
  • EP4422873B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a printing device (100) for printing a workpiece, to a machine comprising such a printing device and to a corresponding method. A workpiece of this type is in particular a plate-shaped workpiece which is, for example, at least partially made from wood or wood materials.