Print Image Inspection Calibration for Color and Position Drift

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Solution Overview

Problem

Existing image inspection systems fail to notify users of the need for calibration before a color value deviation occurs, leading to continued printing with abnormalities, and do not account for deviations in print position.

Innovation Solution

An image inspection apparatus that includes a calibration unit to adjust lookup tables and distortion parameters based on calibration charts, align scanned and reference images, and perform image comparison to detect abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If calibration is performed only after color value deviation is confirmed, then the inspection system maintains simple operation, but printing abnormalities occur and quality decreases

Engineering Contradiction:
Improveprint qualityVSAvoidcalibration operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary calibration by predicting color value deviations based on sheet information before actual printing occurs. The calibration determination unit predicts deviations using stored prediction values associated with different sheet types, and the calibration execution unit performs calibration in advance when predicted deviations exceed thresholds, preventing printing abnormalities before they occur.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the inspection system only checks color values, then the system remains simple, but it cannot detect print position deviations that also affect quality

Engineering Contradiction:
Improveimage qualityVSAvoidinspection parameters
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inspection system is enhanced to perform multiple types of inspections simultaneously. The same inspection apparatus that checks color values now also detects print position deviations, sheet distortion, and other abnormalities. The determination unit integrates multiple prediction models (color value deviation, print position deviation, distortion) to comprehensively assess whether calibration is needed, making the system multi-functional without requiring separate dedicated devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If calibration is performed frequently to prevent abnormalities, then print quality improves, but productivity decreases due to more calibration operations

Engineering Contradiction:
Improvecolor accuracyVSAvoidprinting output
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts calibration frequency based on predicted deviation parameters. Different sheet types have different prediction values stored in advance, allowing the system to determine calibration needs quantitatively. The calibration determination unit compares predicted deviations against thresholds to make data-driven decisions about when calibration is necessary, optimizing the balance between quality and productivity by calibrating only when needed rather than on fixed schedules.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4708838A1Image inspection apparatus, image forming apparatus, and image inspection method
Publication Date: 2026.03.11 CANON KK
  • EP4708838A1 patent drawingFigure 1
  • EP4708838A1 patent drawingFigure 2
  • EP4708838A1 patent drawingFigure 3

AI summary

An image inspection apparatus (102) comprises an image inspection means (506) that scans, via a scanning means (403), a sheet on which an image is formed conveyed from an image forming means (202) and detecting an abnormality in a formed image via comparison with a reference image. The image inspection apparatus (102) determines whether or not to execute calibration to adjust the reference image of the formed image, in a case where it is determined to execute calibration, execute calibration and store calibration data thereof in the one or more memory devices, in a case where it is determined not to execute calibration, read out calibration data from the one or more memory devices, and based on calibration data stored in the one or more memory devices or calibration data obtained by execution of the calibration, perform adjustment of the reference image or the formed image.