Movable Foreign Object Detector for Impact Protection

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Solution Overview

Problem

Conventional image forming apparatus person detectors are vulnerable to external impacts, such as when replacing toner cartridges, leading to potential damage of the internal printed circuit boards.

Innovation Solution

A movable detector holding unit with elastic components and a fixing member is integrated into the system, allowing the detector to retract from external impacts by moving into the apparatus body, thus protecting the printed circuit boards from damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed type person detecting system is used, then the detector is stable and easy to install, but it is vulnerable to external impacts causing damage to the printed circuit board

Engineering Contradiction:
Improvedetector protection from impactVSAvoiddetector holding unit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detector holding unit is designed to be movable rather than fixed, allowing it to dynamically respond to external impacts. The holding unit can move in the depth direction when impacted, enabling the detector to retreat from harmful forces while maintaining operational stability during normal use

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the positional parameter of the detector holding unit dynamically. By allowing movement in the depth direction and controlling the distance from the apparatus body front surface, the system adapts to impact conditions while maintaining detection functionality

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the detector holding unit is made movable to avoid impact damage, then the printed circuit board is protected, but the detector may fail to accurately detect persons or foreign objects

Engineering Contradiction:
Improvedetector protection from impactVSAvoidperson or foreign object detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The elastic member applies a preliminary restoring force to keep the detector holding unit in its normal detection position. This pre-applied counteraction ensures that the detector remains properly positioned for accurate detection during normal operation, while still allowing movement when impacted

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The elastic member acts as a cushioning element that absorbs impact energy before it reaches the printed circuit board. By providing elastic restoration, it protects the detector from damage while maintaining positional stability for accurate detection

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the detector holding unit can move during impact, then the printed circuit board is protected from damage, but the structure becomes more complex with additional components

Engineering Contradiction:
Improveprinted circuit board protectionVSAvoiddetector holding unit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic member serves as an intermediary element between the detector holding unit and the apparatus body. This single intermediate component provides both the movement capability and the protective cushioning function, simplifying the overall structure compared to more complex protective mechanisms

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

The solution effectively prevents damage to the person detectors during external impacts, enabling safe replacement of toner cartridges without harming the detector mounted printed circuit boards.

Implementation Method 1

an elastic member to press the detector holding unit from the rear side of the detector holding unit toward a front side of the foreign object detecting system

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

inserting a stepped screw having a diameter being smaller in a range toward a bottom of the stepped screw to form a longitudinal slope, through which the detector holding unit can move, into each of a compression coil spring and the detector holding unit

Methodology Applied
Scientific EffectCompression spring: Spring

Data Source

PatentEP3217220B1Image forming apparatus, foreign object detecting system, and method for producing foreign object detecting system
Publication Date: 2019.10.30 RICOH CO LTD
  • EP3217220B1 patent drawingFigure 1~2
  • EP3217220B1 patent drawingFigure 3~4
  • EP3217220B1 patent drawingFigure 5~6

AI summary

An image forming apparatus (1) includes an apparatus body accommodating an image forming device (10), a foreign object detector (23, 24) that detects a foreign object beside the apparatus body, and a detector holding unit (14) that holds the foreign object detector (23, 24). The foreign object detector (23, 24) and the detector holding unit (14) are movable together into the apparatus body.