Roll Sheet Rewinding Control for Low-Waste Consecutive Printing

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Solution Overview

Problem

Existing recording apparatuses waste paper due to manual rewinding requirements when printing is interrupted, necessitating user intervention and leading to discarded printed areas between leading ends and recorded parts.

Innovation Solution

A recording apparatus with automated rewinding control that minimizes paper waste by reversing sheet conveyance to align leading ends with cutting positions, allowing seamless continuation of printing without manual user intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If manual rewinding operation is implemented to reduce paper waste, then paper waste is reduced, but user intervention is required and operation complexity increases

Engineering Contradiction:
Improvepaper wasteVSAvoiduser intervention requirement
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

The system automatically determines when rewinding is needed and executes the rewinding operation without user intervention. The control unit monitors printing progress and sheet position, automatically initiating rewinding when a job is completed and the next job should start, thereby eliminating the need for manual user action while reducing paper waste.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses detection units to monitor the position of the sheet and the state of the winding portion, providing feedback to the control unit. Based on this feedback, the control unit automatically decides when to rewind and controls the rewinding speed and position, creating a closed-loop system that reduces paper waste without requiring user intervention.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If automated rewinding control is implemented, then user intervention is eliminated and ease of operation improves, but device complexity increases

Engineering Contradiction:
Improveautomation levelVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control unit serves multiple functions: it controls the recording unit during printing, monitors sheet position through detection units, determines when rewinding is necessary, controls the rewinding speed and position, and manages the overall printing workflow. By consolidating these diverse functions into a single multi-functional control unit, the system achieves automation without proportionally increasing overall device complexity.

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

Solution Approach 2:

The system merges the control functions for recording, detection, and rewinding into an integrated control system. The control unit combines the responsibilities of managing print jobs, interpreting detection signals, and executing rewinding operations, thereby reducing the number of separate control components needed and managing complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If the sheet is rewound to align leading ends with cutting positions, then paper waste is minimized and productivity improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveprinting efficiencyVSAvoidsheet positioning precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary positioning actions during the printing process. The detection unit identifies the position of the leading end before the rewinding operation begins, and the control unit calculates the required rewinding distance in advance. This preliminary detection and calculation ensure that when rewinding occurs, the sheet is positioned accurately at the cutting position, minimizing paper waste while maintaining precision through pre-planned positioning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces manual mechanical positioning with an automated control system that uses detection units and controlled rewinding. Instead of relying on manual alignment, the detection unit electronically identifies the leading end position, and the control unit precisely controls the rewinding mechanism to achieve accurate positioning. This substitution of mechanical manual alignment with automated detection and control reduces the precision burden on manual operation while maintaining or improving positioning accuracy.

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

Ensures high-quality recorded products while reducing paper waste by automating the rewinding process, enhancing usability and efficiency in multi-job printing operations.

Implementation Method 1

the sheet conveying unit is configured to convey the roll sheet in a sheet conveying direction and a reverse conveying direction which is opposite to the sheet conveying direction

Methodology Applied
Scientific EffectReversal of conveyance direction:

Data Source

PatentEP4706974A1Recording apparatus
Publication Date: 2026.03.11 CANON KK
  • EP4706974A1 patent drawingFigure 1
  • EP4706974A1 patent drawingFigure 2
  • EP4706974A1 patent drawingFigure 3

AI summary

A recording apparatus includes a setting unit for providing a setting for collecting a product, in advance, when a plurality of images is to be recorded consecutively onto a sheet, for a first job and a second job following the first job, the product including a first image recorded on the sheet for the first job. When the setting is made by the setting unit, and a feeding portion and a winding portion are caused to execute a rewinding operation for conveying the sheet in a reverse conveying direction, the control portion executes a first operation of starting recording a second image for the second job following the first job, on a second area following a first area of the sheet, the first area being an area where the first image is recorded, and stopping recording the second image halfway through.