Image Forming Apparatus Jam Handling Back-EMF Protection

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Solution Overview

Problem

Existing image forming apparatuses face issues with protecting loads from back electromotive force generated during jam handling, as existing solutions cannot cut off power supply to the motor while decelerating its rotation, potentially leading to load breakdown and safety concerns.

Innovation Solution

The apparatus selectively supplies regenerative power to specific loads based on the increase rate of back electromotive force, ensuring that loads with the minimum withstand voltage are protected by diverting regenerative energy to other loads, thereby preventing breakdown and ensuring user safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If power supply is cut off from the motor to ensure user safety during jam handling, then user safety is improved, but the motor cannot be decelerated and loads remain vulnerable to back electromotive force

Engineering Contradiction:
Improveuser safetyVSAvoidload protection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a diode as an intermediary component in the power supply circuit. The diode allows current to flow in only one direction, enabling the system to cut off power supply to the motor (protecting users) while simultaneously providing a path for regenerative power to be supplied to loads (protecting loads from back electromotive force). This intermediary component resolves the contradiction by enabling both safety and load protection simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If regenerative power is supplied to loads to protect them from back electromotive force, then load protection is improved, but user safety may be compromised due to potential motor rotation

Engineering Contradiction:
Improveload protectionVSAvoiduser safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The diode acts as a directional valve in the electrical circuit, allowing regenerative power to be routed to loads while preventing reverse current that could cause motor rotation. This intermediary component enables the system to protect loads from back electromotive force without compromising user safety, as the diode's unidirectional conductivity ensures that power flows only from the motor to the loads and not vice versa.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If power supply is maintained to the motor for deceleration control, then load protection is improved, but user safety deteriorates due to risk of accidental rotation

Engineering Contradiction:
Improveload protectionVSAvoiduser safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The diode intermediary component enables the system to maintain power supply for load protection while preventing the reverse current path that would allow accidental motor rotation. By blocking current flow in the reverse direction, the diode ensures that even if the motor attempts to rotate accidentally, power cannot be supplied back to the motor, thus maintaining both load protection and user safety simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively prevents load breakdown and ensures user safety by automatically selecting loads to consume regenerative power, reducing manufacturing costs and enhancing operational safety during jam handling.

Implementation Method 1

The rotation of the motor produces regenerative power (regenerative energy by self-power generation of the motor). Back electromotive force (back electromotive voltage) of this regenerative power may break down a load (device) in the image forming apparatus

Methodology Applied
Scientific EffectBack electromotive force: Electromagnetic Induction

Data Source

PatentEP2762980B1Image forming apparatus detecting occurrence of Jam
Publication Date: 2021.05.05 KONICA MINOLTA INC
  • EP2762980B1 patent drawingFigure 1
  • EP2762980B1 patent drawingFigure 2
  • EP2762980B1 patent drawingFigure 3

AI summary

An image forming apparatus (1) includes a timing roller (39) for conveying paper in the image forming apparatus (1), a first motor (MB1) receiving supply of electric power from a power source (100) for driving the timing roller (39), a second motor (MA1, MA6), receiving supply of electric power from the power source (100), a sensor (SR9) for detecting whether a jam occurs at the timing roller (39), a drive relay (101) for cutting off supply of electric power from the power source (100) to the first and second motors (MA1, MA6, MB1), if occurrence of a jam is detected, and a control circuit (111) for controlling an operating state of the second motor (MA1, MA6) such that regenerative power produced at the first motor (MB 1) due to rotation of the timing roller (39) is supplied to the second motor (MA1, MA6), if occurrence of a jam is detected.