Roll-fed printer reverse printing for double-sided web error recovery

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Solution Overview

Problem

Existing roll-fed printers face challenges in minimizing web loss and maintaining print quality when errors occur during double-sided printing, especially when errors happen on the backside after the front side is fully printed.

Innovation Solution

The method involves determining the remaining unprinted images on the second side after a print error, rewinding the web, and then printing the remaining images in reverse order on the second side once the web is reinserted.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If printing continues after an error occurs on the back side of the web, then productivity is maintained, but print quality deteriorates and web loss increases

Engineering Contradiction:
Improveprinting efficiencyVSAvoidprint quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

When an error is detected during back-side printing, the system reverses the normal workflow by stopping printing, rewinding the web to the input holder, and re-printing the remaining images in reverse order. This inversion of the printing sequence ensures that only correctly printed images are produced while maximizing web utilization.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system recovers unprinted portions of the web by rewinding them back to the input holder after an error occurs, rather than discarding the entire web roll. This allows the remaining printable images to be re-printed in reverse order, minimizing web waste while maintaining print quality standards.

Inventive Principle:
Principle #34Discarding and recovering

2Manufacturing precision

If the web is stopped and rewound after an error on the back side, then print quality is maintained, but web loss increases and productivity decreases

Engineering Contradiction:
Improveprint qualityVSAvoidweb loss
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

Instead of discarding the entire web roll when an error occurs, the system recovers the unprinted portion by rewinding it to the input holder. The remaining images are then re-printed in reverse order, ensuring that minimal web is wasted while maintaining high print quality standards.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The system performs preliminary assessment of the error impact before deciding to rewind and re-print. By determining which specific images are affected and calculating the optimal rewind point, the system minimizes web loss while ensuring all defective images are excluded from the final output.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If images are re-printed in reverse order after a rewind, then correct front-back registration is achieved, but printing time increases

Engineering Contradiction:
Improvefront-back registrationVSAvoidprinting time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system prints remaining images in reverse order after rewinding, which ensures correct front-back registration because the web is fed from the same input holder position as the original printing. This inversion of the printing sequence eliminates registration errors while the system optimizes the process to minimize additional printing time.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4119353B1Roll-fed printer, software medium and method for double-sided printing on a web
Publication Date: 2025.03.05 CANON PRODN PRINTING HLDG BV
  • EP4119353B1 patent drawingFigure 1
  • EP4119353B1 patent drawingFigure 2A~2B
  • EP4119353B1 patent drawingFigure 2C

AI summary

When printing on a frontside of a web is completed and an error occurs when printing on a backside of the web, a remaining part of the images is determined which were intended to be printed on the backside but which have not yet been printed due to the print stop. The web is fed forward towards the output holder until the web is completely wound up at the output holder. The web is inserted again at the input holder in order to allow a start of printing the remaining part of the images in a reverse order on the remaining part of the backside of the web.