Tandem Inkjet Printing Unit with Offset Nozzles for Compact Output

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Solution Overview

Problem

Existing inkjet printing systems face challenges in minimizing the print zone width, achieving high-speed full-color printing with multiple redundancy, and simplifying printhead alignment and replacement while maintaining optimal print quality.

Innovation Solution

A printing unit with a pair of opposed inkjet modules mounted in tandem, each having printheads with 180-degree rotational symmetry and offset nozzle rows, allowing for compact design, reduced print zone span, and improved print quality by aligning nozzle rows to mask print artefacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple printheads are arranged along the media feed path for full-color printing with redundancy, then print quality and reliability are improved, but the print zone span and device complexity increase

Engineering Contradiction:
Improveprint qualityVSAvoidprint zone span
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent applies 180-degree rotational symmetry to arrange printheads in a tandem configuration where opposing printheads are rotated relative to each other. This dimensional transformation allows the system to achieve full-color printing with redundancy while minimizing the linear span along the media feed path, as the printheads utilize vertical and lateral spacing rather than extending the print zone in the feed direction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If printheads are precisely aligned for high-quality printing, then print quality is improved, but set-up costs and alignment complexity increase

Engineering Contradiction:
Improveprinthead alignmentVSAvoidset-up costs
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs asymmetric offset positioning of compensatory nozzle rows between opposing printheads. By deliberately introducing a controlled asymmetric offset in the nozzle row positions, the system simplifies alignment procedures while maintaining print quality, as the offset compensates for variations in printhead positioning and eliminates the need for precise alignment of all nozzle rows.

Inventive Principle:
Principle #4Asymmetry

3Manufacturing precision

If compensatory nozzles are aligned between opposing printheads, then print artefacts are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveprint artefact minimizationVSAvoidnozzle row configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements asymmetric offset positioning of compensatory nozzle rows between opposing printheads. Instead of aligning compensatory nozzles symmetrically, the design introduces a deliberate offset that simplifies the overall configuration while effectively minimizing print artefacts through the rotational symmetry of the tandem arrangement.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4511236B1Printing unit with tandem inkjet modules
Publication Date: 2025.08.06 MEMJET TECH LTD
  • EP4511236B1 patent drawingFigure 1
  • EP4511236B1 patent drawingFigure 2~3
  • EP4511236B1 patent drawingFigure 4~5

AI summary

A printing unit includes: a unit chassis and a pair of opposed inkjet modules mounted in tandem on the unit chassis in forward and reverse orientations, each inkjet module having one respective printhead and at least one of: a capper and a wiper. Each printhead includes first and second rows of print chips mounted on a unitary surface of a respective ink manifold, the first and second rows of print chips having a plurality of print chips butted end-on-end along a length of the printhead. The printheads are wholly aligned with respect to a media feed direction for printing in four ink colors from the pair of printheads.