Defect Reproducibility Determination Using Phase Information

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Solution Overview

Problem

Existing inspection systems for print defects require significant time and cost, as they rely on visual determination of reproducibility even when using automated inspection, and struggle to accurately determine defect reproducibility due to variations in defect positions caused by factors like photosensitive drum and intermediate transfer belt cycles, paper length, and image formation timelines.

Innovation Solution

An image processing apparatus connected to a printing apparatus that receives reference and scanned images, detects defects by comparing pixel values, and determines reproducibility based on phase information of the image bearing member, allowing for accurate assessment of defect reproducibility even when defect positions vary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual inspection is used to determine defect reproducibility, then accuracy of defect assessment is improved, but inspection time and cost increase significantly

Engineering Contradiction:

Improvedefect reproducibility assessment accuracyVSAvoidinspection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual visual inspection mechanism with an automated image processing system that uses pixel value comparison and phase information calculation to objectively determine defect reproducibility, thereby eliminating the time-consuming visual assessment while maintaining or improving accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces phase information as an intermediary parameter that bridges the gap between defect position variations and reproducibility assessment. By calculating phase information from image bearing member data and comparing it with scanned image defect positions, the system can accurately assess reproducibility without manual intervention

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If automated inspection is used to reduce inspection time, then productivity is improved, but ability to accurately determine defect reproducibility deteriorates due to position variations

Engineering Contradiction:

Improveinspection efficiencyVSAvoiddefect reproducibility determination accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent transforms the defect assessment from direct position matching to phase information comparison. By changing the parameter from absolute defect position to phase information (which accounts for position variations due to drum/belt cycles, paper length, etc.), the system maintains high accuracy in automated inspection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adds the dimension of phase information calculation based on image bearing member data (photosensitive drum rotation phase, intermediate transfer belt position). This additional dimensional information enables the system to compensate for position variations and accurately determine reproducibility in automated inspection

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If defect position matching is performed without phase information, then processing complexity is reduced, but reproducibility determination accuracy deteriorates due to position variations from drum cycles and paper length

Engineering Contradiction:

Improveprocessing complexityVSAvoiddefect position matching accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculation of phase information from image bearing member data before conducting defect comparison. By pre-calculating the expected defect positions based on drum rotation phase and belt position, the system accurately matches defects despite position variations without excessive complexity

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11627226B2Image processing apparatus, control method, and product for determining defect reproducibility based on defect positions on recording media calculated from phase information

Publication Date: 2023.04.11 CANON KK

AI summary

This disclosure provides an image processing apparatus that is connected to a printing apparatus, sequentially receives a plurality of recording media on which printing was performed by the printing apparatus, and inspects a quality of images formed on the recording media, wherein the image processing apparatus receives a reference image, acquires a plurality of scanned images by sequentially scanning the recording media output from the printing apparatus and having the images to be inspected recorded thereon, receives phase information of an image bearing member of the printing apparatus, detects, for each of the scanned images, a defect on the scanned image by comparing a pixel value of the reference image and a pixel value of the scanned image, and determines whether a defect has reproducibility based on positions of defects on the recording media calculated from the phase information.