Velocity Sensor Skew Detection for Roll-to-Roll Media

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Solution Overview

Problem

Existing recording apparatuses face challenges in detecting the skewed state of transportation target media with high precision, particularly in roll-to-roll transportation structures, where traditional methods relying on leading edge detection are ineffective.

Innovation Solution

The implementation of a recording apparatus equipped with a pair of velocity sensors positioned at different points along the transportation path, calculating the velocity difference to detect the skewed state, allowing for high-precision detection even with sensors that cannot measure absolute velocities accurately, and enabling correction of the skew based on these measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If leading edge detection method is used to judge medium inclination, then skew detection can be performed for sheet media, but it cannot be applied to roll-to-roll transportation structures

Engineering Contradiction:
Improveapplicability to different transportation structuresVSAvoidskew detection capability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/optical leading edge detection system with a velocity-based detection system using sensors that measure transport velocity. This substitution enables skew detection to work with roll-to-roll transportation structures while maintaining detection capability, as velocity measurement does not depend on detecting the leading edge of discrete sheets.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If velocity sensors are positioned at different points in the intersecting direction, then skew detection precision is improved, but the system requires multiple sensors increasing device complexity

Engineering Contradiction:
Improveskew detection precisionVSAvoidnumber of velocity sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the velocity measurement function by positioning multiple velocity sensors at different points in the intersecting direction. Each sensor measures velocity at its specific location, and the control unit processes these segmented measurements to calculate velocity differences, thereby achieving precise skew detection through distributed measurement points.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If velocity difference calculation is used for skew detection, then high precision detection is achieved even with sensors that cannot measure absolute velocity accurately, but additional calculation processing is required

Engineering Contradiction:
Improveskew detection accuracyVSAvoidcalculation processing requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback-based skew detection system where the control unit continuously calculates velocity differences from velocity sensor measurements and uses this feedback to determine medium skew. This feedback mechanism enables high-precision skew detection relative to the transport direction by comparing velocities at different positions, compensating for limitations in absolute velocity measurement accuracy.

Inventive Principle:
Principle #23Feedback

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

This approach enables precise detection and correction of skewed states in both roll-to-roll and non-roll-to-roll transportation systems, improving design flexibility and accuracy by compensating for the limitations of existing sensor technologies.

Implementation Method 1

the sensor 8 is configured to emit an electromagnetic wave to the medium P, to receive the electromagnetic wave reflected from the medium P, and to calculate the transportation velocity of the medium P from a frequency change due to a Doppler effect

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP3020667B1Transportation apparatus and recording apparatus
Publication Date: 2020.08.19 SEIKO EPSON CORP
  • EP3020667B1 patent drawingFigure 1
  • EP3020667B1 patent drawingFigure 2
  • EP3020667B1 patent drawingFigure 3

AI summary

A transportation apparatus (1) comprises: a first velocity sensor (8a, 8c) that detects transportation velocity of a medium (P) that is transported; a second velocity sensor (8b, 8d) that detects transportation velocity of the medium and is provided at a position different from that of the first velocity sensor in an intersecting direction (B) as viewed in a transportation direction (A) of the medium, the intersecting direction intersecting with the transportation direction; and a skew detection section (18) that calculates a velocity difference from the velocities detected by the first and second velocity sensors (8a, 8b, 8c, 8d), and detects a skewed state of the medium on the basis of the velocity difference.