Print Verification System Nozzle Defect Classification

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Solution Overview

Problem

High-speed ink jet printers face nozzle clogging due to solvent evaporation, paper dust accumulation, and air bubbles, leading to degraded print quality and inefficient defect detection in current Print Verification Systems (PVS) that only provide approximate estimates of defective nozzle locations without type classification.

Innovation Solution

A Print Verification System (PVS) that includes image readers to analyze print data from the medium, a control unit to locate and classify artifacts caused by defective nozzles, and a process involving optical density signatures and de-convolution techniques to accurately detect, classify, and count defective nozzles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-speed ink jet printing is performed, then printing speed and productivity are improved, but nozzle clogging occurs more frequently due to solvent evaporation and paper dust accumulation

Engineering Contradiction:
Improveprinting speedVSAvoidnozzle functionality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary detection of defective nozzles by capturing and analyzing printed test patterns before normal printing operations continue. The PVS reads the test pattern and identifies clogged nozzles early, allowing preventive maintenance before quality degradation occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback by monitoring print quality in real-time through the PVS, which provides information about nozzle defects back to the printing system, enabling dynamic adjustment and maintenance scheduling based on actual nozzle performance

Inventive Principle:
Principle #23Feedback

2Difficulty of detecting and measuring

If traditional Print Verification Systems are used, then basic defect detection is provided, but only approximate estimates of defective nozzle locations are given without type classification

Engineering Contradiction:
Improvedefect detection capabilityVSAvoiddefect type information
Core Design Contradiction:
Difficulty of detecting and measuringVSLoss of information

Solution Approach 1:

The system segments the defect detection process into distinct analysis components: location identification, artifact type classification, and defect characterization. By analyzing specific pattern characteristics in different regions of the test pattern, the system provides detailed information about each defective nozzle's location and defect type

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses variations in optical density and artifact appearance (analogous to color changes) to classify different types of nozzle defects. Different defect types produce distinct visual patterns in the printed test data, which the PVS analyzes to determine the specific nature of each defect

Inventive Principle:
Principle #32Color changes

3Ease of operation

If manual inspection methods are used, then simple defect identification is possible, but the process is time-consuming and lacks precision in locating and classifying defective nozzles

Engineering Contradiction:
Improveinspection simplicityVSAvoiddefect location precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system replaces manual mechanical inspection with an automated optical measurement system. The PVS uses image readers and control units to automatically capture, process, and analyze printed test patterns, eliminating the need for manual visual inspection while providing precise location and classification data for each defective nozzle

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

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

The system effectively detects, classifies, and counts defective nozzles, facilitating efficient corrective actions and improving print quality by providing precise defect information, thereby enhancing the reliability and efficiency of nozzle maintenance.

Implementation Method 1

analyzing the image data to locate and classify artifacts on the medium caused by defective print engine nozzles

Methodology Applied
Scientific EffectOptical density measurement: Absorption (EM radiation)

Data Source

PatentUS8820880B2Defective nozzle detection mechanism
Publication Date: 2014.09.02 RICOH CO LTD
  • US8820880B2 patent drawing
  • US8820880B2 patent drawing
  • US8820880B2 patent drawing

AI summary

A method is disclosed. The method includes receiving image data from one or more image readers and analyzing the image data to locate and classify artifacts on the medium caused by defective print engine nozzles.