Image Forming Inspection Recovery for Inline and Offline Printing

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Solution Overview

Problem

Existing image forming systems capable of both inline and offline inspection lack effective recovery processes when abnormal sheets are detected, leading to inefficiencies in handling defective prints.

Innovation Solution

The system includes an inspection apparatus that compares formed images with pre-registered correct answer images, determining abnormalities and implementing recovery processes such as reprinting on normal sheets, shifting, or logging defects, with modes tailored for inline and offline inspections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If both inline inspection and offline inspection capabilities are provided in the image forming system, then inspection versatility is improved, but device complexity increases and no recovery process is available when abnormalities occur

Engineering Contradiction:
Improveinspection versatilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The image forming system integrates both inline inspection and offline inspection capabilities into a single unified system. The inspection apparatus can operate in two modes: inline mode where sheets are inspected immediately after printing, and offline mode where sheets are inspected after being stored in the sheet storage unit. This multi-functionality allows the system to adapt to different inspection requirements while maintaining a single integrated architecture, resolving the contradiction between versatility and complexity by providing both inspection modes through one unified system design

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

2Productivity

If recovery process is implemented for abnormal sheets in inline inspection, then productivity is improved by preventing missing pages, but device complexity increases due to additional discharge units and control mechanisms

Engineering Contradiction:
Improveprocessing efficiencyVSAvoiddischarge unit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

When an abnormal sheet is detected during inline inspection, the system automatically executes a recovery process without requiring additional complex discharge units. The abnormal sheet information is stored, and the system reprints the correct image on a new sheet using the stored print data. This self-service approach allows the system to correct defects internally through software control and data management rather than requiring additional physical discharge mechanisms, thereby improving productivity while avoiding increased device complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The recovery process creates a copy of the correct image from stored print data and outputs it as a replacement for the abnormal sheet. Instead of attempting to repair or reprocess the original abnormal sheet, the system generates a new sheet with the correct image by copying the intended print data, effectively replacing the defective output without requiring complex mechanical intervention on the original sheet

Inventive Principle:
Principle #26Copying

3Reliability

If recovery process is implemented for abnormal sheets in offline inspection, then reliability is improved by enabling defect correction, but device complexity increases due to coordination between inspection apparatus and image forming units

Engineering Contradiction:
Improvedefect correction capabilityVSAvoidcoordination complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements a feedback mechanism where inspection results from offline inspection are communicated back to the image forming units. When an abnormal sheet is detected during offline inspection, the abnormal sheet information is fed back to the printing apparatus or copying apparatus, which then executes the recovery process by reprinting the correct image. This feedback loop enables automatic defect correction without requiring complex real-time coordination during the inspection phase, as the recovery action is triggered and controlled through structured information exchange after inspection completion

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary storage of print data and abnormal sheet information before the recovery process is executed. During offline inspection, when an abnormality is detected, the system has already retained the necessary print data and sheet information, allowing the recovery process to proceed efficiently by simply retrieving and reprinting the stored data rather than requiring complex real-time coordination or data reconstruction, thus improving reliability while managing complexity through advance preparation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4155829B1Image forming system and control method
Publication Date: 2025.07.16 CANON KK
  • EP4155829B1 patent drawingFigure 1
  • EP4155829B1 patent drawingFigure 2
  • EP4155829B1 patent drawingFigure 3

AI summary

An image forming system (101) includes an image forming unit (107), an inspection unit (109), a conveyance unit (108) arranged to convey a sheet to the inspection unit (109), a controller (102, 222, 233, 238, 245) configured to execute a first inspection mode in which a sheet having an image formed thereon is conveyed by the conveyance unit (108) to the inspection unit (109) and is inspected, and a second inspection mode in which, without executing image forming by the image forming unit (107), a sheet is conveyed by the conveyance unit (108) to the inspection unit (109) and is inspected, and a setting unit (222) arranged to set a recovery process. The setting unit (222) permits the setting of the recovery process in the first inspection mode and prohibits the setting of the recovery process in the second inspection mode.