Bent Light Guide for Medium Conveyance Path Detection

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Solution Overview

Problem

Existing medium conveying apparatuses face challenges in accurately detecting the state of media during conveyance, particularly in preventing jamming and skewing, due to limitations in early detection of medium position and presence, which can lead to damage and inefficiencies.

Innovation Solution

The apparatus incorporates a set guide, feed roller, conveying rollers, and a light emitting and receiving element system with bent light guides to detect media presence and position accurately, using a light emitting element and a light receiving element positioned on the outside of the conveyance path with a guide pair to regulate the medium path, allowing for early detection and prevention of jams and skewing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If light emitting and receiving elements are positioned close to the medium conveyance path for early detection, then detection timing is improved, but the apparatus becomes vulnerable to medium interference and damage

Engineering Contradiction:

Improvedetection timingVSAvoidmedium interference

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent introduces light guides as intermediary components that transmit light signals between the light emitting/receiving elements and the medium conveyance path. The light guides act as mediators that allow the detection system to be positioned away from the medium path while still detecting medium presence and position accurately, thus avoiding direct interference from the medium.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent positions the light emitting and receiving elements in a location separated from the medium conveyance path by using bent light guides. This spatial repositioning moves the detection system to another dimension (away from the direct medium path), allowing early detection without exposing the sensitive elements to medium interference or damage risks.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If light guides are used to position light emitting and receiving elements away from the medium conveyance path, then protection from medium interference is improved, but light guide complexity increases

Engineering Contradiction:

Improvemedium interferenceVSAvoidlight guide complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs bent (curved) light guides instead of straight ones to route light signals around obstacles and reach the detection position. The curvature of the light guides allows them to navigate the spatial constraints of the apparatus while protecting the light emitting and receiving elements from medium interference, accepting the trade-off of increased structural complexity for improved protection.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If detection elements are positioned on the downstream side to avoid moving mechanism interference, then reliability is improved, but detection precision for early position detection decreases

Engineering Contradiction:

Improvedetection reliabilityVSAvoidposition detection precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces direct mechanical/optical alignment methods with light guide-based light transmission to achieve detection. By using light guides to transmit light signals over distance, the system maintains detection precision despite the increased distance between the detection elements and the medium, thus achieving both reliability (by avoiding moving mechanism interference) and precision (through effective light transmission).

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables early detection of media presence and position, preventing jams and skewing, thus ensuring efficient and damage-free conveyance of various media types, including thick documents like passports.

Implementation Method 1

a first light guide which is bent so as to guide a light emitted from the light emitting element to the first opening, and a second light guide which is bent so as to guide the light incident from the second opening to the light receiving element

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS11623831B2Medium conveying apparatus including light guide which is bent

Publication Date: 2023.04.11 PFU LTD

AI summary

A medium conveying apparatus includes a moving mechanism to move the set guide, a guide pair including a first guide having a first opening and a second opening, and a second guide to regulate a vertical direction of the medium conveyance path, a light emitting element and a light receiving element located on an outside of the medium conveyance path with the first guide in between, and on the downstream side of the first opening and the second opening so as to be apart from the moving mechanism by a predetermined distance or more in the medium conveying direction, a first light guide which is bent so as to guide a light emitted from the light emitting element to the first opening, and a second light guide which is bent so as to guide the light incident from the second opening to the light receiving element.