Nozzle Malfunction Detection in Digital Printing Presses

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Solution Overview

Problem

Digital printing presses face challenges in detecting and classifying malfunctioning nozzles, which can result in noticeable defects in printed images, leading to substrate waste and reduced quality.

Innovation Solution

A method and system that utilize a nozzle pattern and/or a uniformity pattern to identify and classify malfunctioning nozzles by analyzing images acquired from an imager, determining the location and type of malfunction through nozzle locators and strength scores, enabling the detection of missing, deviated, inconsistent, and redundant nozzles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a digital printing press operates continuously to maximize productivity, then output increases, but malfunctioning nozzles may go undetected causing substrate waste and quality issues

Engineering Contradiction:
Improvecontinuous printing outputVSAvoidnozzle functionality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary nozzle detection by printing test patterns before production printing. The imager captures images of these patterns to identify malfunctioning nozzles in advance, allowing the system to rectify issues through software compensation before they affect production quality or cause substrate waste.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where the imager continuously monitors printed test patterns, detects nozzle malfunctions, and provides information to the controller. The controller then adjusts print data in real-time to compensate for detected issues, enabling continuous operation without quality degradation.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the printing press stops to detect and repair malfunctioning nozzles, then print quality is maintained, but productivity decreases due to interruptions

Engineering Contradiction:
Improveprint qualityVSAvoidprinting throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs self-diagnosis by automatically detecting malfunctioning nozzles through test pattern imaging and analysis. The controller automatically generates compensation data without human intervention, allowing the press to maintain quality while minimizing stops. Only when compensation is insufficient does the system require manual nozzle maintenance.

Inventive Principle:
Principle #25Self-service

3Productivity

If malfunctioning nozzles are not detected, then productivity is maintained, but substrate waste increases due to unprintable material

Engineering Contradiction:
Improveprinting outputVSAvoidsubstrate waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The system identifies malfunctioning nozzles before production printing begins through test pattern analysis. By detecting issues in advance and applying software compensation, the system prevents defective printing that would otherwise result in substrate waste, allowing continuous production of quality material.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If a detailed test pattern is printed to detect all nozzle malfunctions, then detection precision improves, but the time required for detection increases

Engineering Contradiction:
Improvenozzle malfunction detection accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The test pattern is segmented into multiple sections, each targeting specific nozzle groups or malfunction types. The imager captures and analyzes these segments systematically, allowing comprehensive detection without requiring a single excessively large test pattern, thus balancing detection completeness with time efficiency.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3442798B1System and methods for detecting malfunctioning nozzles in a digital printing press
Publication Date: 2022.04.13 ADVANCED VISION TECHNOLOGY (AVT) LTD
  • EP3442798B1 patent drawingFigure 1
  • EP3442798B1 patent drawingFigure 2
  • EP3442798B1 patent drawingFigure 3A~3B

AI summary

A method of identifying at least one malfunctioning nozzle in a digital printing press, the digital printing press including a plurality of nozzles. The method includes the procedures of printing a design on a substrate, acquiring at least one image of the printed design and identifying at least one artifact in the acquired image. The method further includes the procedure of identifying the malfunctioning nozzle and classifying the at least one malfunction nozzle according to at least a portion of a combined pattern.