Multi-feed Prevention Roller Wear Detection via Hall Sensor

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Solution Overview

Problem

The existing sheet feeding apparatuses in image forming systems face issues such as miss-feed, jam, and multi-feed due to worn-out rollers, leading to improper image formation when the pickup roller, sheet feeding roller, and multi-feed prevention roller are not replaced in time, typically after feeding a predetermined number of sheets, such as 200,000.

Innovation Solution

A sheet feeding apparatus equipped with a magnetic torque limiter and hall sensors that perform self-diagnosis to detect the wear state of the multi-feed prevention roller, determining when it needs replacement, and inform the user to replace it along with the sheet feed roller and pickup roller, thereby preventing sheet feeding failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rollers are not replaced after a predetermined number of sheets, then the device complexity is reduced, but the reliability deteriorates due to wear-out causing miss-feed, jam, and multi-feed

Engineering Contradiction:
Improvesheet feeding reliabilityVSAvoidroller replacement management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by implementing a self-diagnosis function that detects roller wear-out before it causes sheet feeding failures. The system monitors the rotation of the multi-feed prevention roller and compares it with the sheet feed roller rotation, identifying wear conditions in advance so that replacement can be scheduled proactively rather than reactively after failures occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using hall sensors to continuously monitor the rotation state of the rollers and providing real-time information about wear conditions. The system compares the rotation amounts of different rollers and feeds back this information to the control unit, which then determines when replacement is necessary, enabling proactive maintenance scheduling.

Inventive Principle:
Principle #23Feedback

2Reliability

If multi-feed detection apparatus is added, then the reliability is improved by detecting multi-feed, but the device complexity increases

Engineering Contradiction:
Improvemulti-feed detection capabilityVSAvoiddetection apparatus complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by making the self-diagnosis function serve multiple purposes: it not only detects multi-feed conditions but also monitors roller wear-out, determines replacement timing, and provides proactive maintenance information. This multi-functional approach eliminates the need for separate dedicated detection apparatus for each function, thereby reducing overall system complexity.

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

Solution Approach 2:

The system implements self-service by enabling the sheet feeding apparatus to automatically monitor its own roller conditions through integrated sensors and control units. The apparatus self-diagnoses wear-out conditions and determines when replacement is needed without requiring external monitoring equipment or manual inspection, simplifying the overall system architecture.

Inventive Principle:
Principle #25Self-service

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

The solution effectively prevents sheet feeding failures by ensuring timely replacement of worn-out rollers, maintaining proper sheet feeding and image formation quality, and reducing maintenance costs by identifying the need for replacement before significant issues arise.

Implementation Method 1

A magnetic torque limiter is provided in the multi-feed prevention roller

Methodology Applied
Scientific EffectMagnetic torque limiter: Magnetic Field

Implementation Method 2

A hall sensor is disposed at one side of the magnetic torque limiter and detects a magnetic force radiated from the magnetic torque limiter

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3509852B1Usage determination of multi-feed prevention roller
Publication Date: 2022.03.23 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3509852B1 patent drawingFigure 1~2
  • EP3509852B1 patent drawingFigure 3~5
  • EP3509852B1 patent drawingFigure 6~7

AI summary

A sheet feeding apparatus includes a sheet stacker to stack at least one sheet; a sheet feed roller disposed at one side of the sheet stacker and to feed a sheet fed from the sheet stacker; a multi-feed prevention roller disposed to face the sheet feed roller and to prevent multi-feed of the sheet fed from the sheet stacker; a magnetic torque limiter disposed coaxially with the multi-feed prevention roller; a hall sensor disposed at one side of the magnetic torque limiter and to detect rotation of the magnetic torque limiter; and a controller configured to rotate the sheet feed roller in a state in which the sheet feed roller and the multi-feed prevention roller are in contact with each other without a sheet and to identify a lifetime of the multi-feed prevention roller by using a signal output from the hall sensor.