Magnetic Roller Pitch Alignment for Belt Position Detection

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Solution Overview

Problem

In printing apparatuses, the magnetic interactions between a magnetic marker on a transporting belt and a magnetic roller can lead to position detection errors over time, especially when the belt is used for extended periods, due to changes in magnetic forces affecting the belt's position detection system.

Innovation Solution

A printing apparatus with a cylindrical magnetic roller having an outer surface that matches the pitch of a magnetic scale on the belt, ensuring consistent magnetic pole alignment and minimizing position deviation, combined with a control unit for adjusting relative positions to maintain accurate detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the roller is constituted of a magnetic body to improve durability and facilitation during manufacturing, then manufacturing ease and durability are improved, but magnetic interactions between the roller and magnetic marker cause position detection errors

Engineering Contradiction:

Improveease of manufactureVSAvoidposition detection precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of the roller's magnetic properties by controlling the magnetization direction to be perpendicular to the belt's movement direction. This parameter change reduces the magnetic interaction strength between the roller and magnetic marker, thereby minimizing position detection errors while maintaining the roller's magnetic body construction for ease of manufacture and durability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful magnetic interaction into a beneficial effect by utilizing the magnetic field generated by the roller in a controlled manner. The magnetization perpendicular to the movement direction creates a magnetic field that does not interfere with the magnetic marker's position detection, while still allowing the roller to function effectively as a transporting component

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If the roller is constituted of a non-magnetic body to prevent magnetic interactions, then position detection precision is improved, but durability and facilitation during manufacturing deteriorate

Engineering Contradiction:

Improveposition detection precisionVSAvoidease of manufacture

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of changing the material type from magnetic to non-magnetic, the patent changes the magnetization parameter of the magnetic body to be perpendicular to the belt's movement direction. This allows the roller to remain magnetic for ease of manufacture while the specific magnetization orientation minimizes interference with position detection

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the magnetic marker's magnetic force is strengthened to improve detection accuracy, then position detection precision is improved, but magnetic interactions with the roller cause greater position deviation over time

Engineering Contradiction:

Improveposition detection precisionVSAvoidposition detection reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the magnetization direction parameter of the roller to be perpendicular to the belt's movement direction. This parameter change reduces the magnetic interaction strength between the roller and magnetic marker, thereby maintaining position detection precision while improving reliability over extended operation periods

Inventive Principle:

Principle #35Parameter changes

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 configuration maintains accurate position detection of the transporting belt by preventing weakening of magnetic forces, thus enhancing the reliability and longevity of the belt's position detection system.

Implementation Method 1

a magnetic scale is arranged at the transporting belt along a transport direction of the printing medium, the magnetic scale having a magnetic pole changing at a predetermined pitch

Methodology Applied

Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 2

the roller has an outer circumferential surface constituted of a magnetic body, and is in contact with the transporting belt at the outer circumferential surface

Methodology Applied

Scientific EffectMagnetism: Magnetism

Data Source

PatentEP3842249B1Printing apparatus and method of controlling printing apparatus

Publication Date: 2023.04.19 SEIKO EPSON CORP

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AI summary

A printing apparatus (100) includes a printing unit (40) that performs printing on a printing medium, a transporting belt (70) that transports the printing medium and has an endless shape, and a belt-driving roller (50) that causes the transporting belt to circulate and has a cylindrical shape. In the transporting belt (70) , a magnetic scale (71) having a magnetic pole changing at a predetermined pitch (P) is arranged along a transport direction of the printing medium. The belt-driving roller (50) includes an outer circumferential surface constituted of a magnet body, and is in contact with the transporting belt at the outer circumferential surface. The circumferential length of the outer circumferential surface of the belt-driving roller is an integer multiple of the pitch of the magnetic scale.