Imaging Unit Guide Mechanism for Document Thickness Detection

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Solution Overview

Problem

Existing medium conveyance apparatuses struggle to accurately distinguish between thick documents and double feeds of thin documents, leading to erroneous detections and potential misinterpretation of document thickness, which affects the output of imaging apparatuses.

Innovation Solution

A medium conveyance apparatus with a first and second unit on either side of the conveyance path, an imaging unit, a reference plate, and a detecting unit that captures images and detects the medium, allowing for the differentiation of document thickness and preventing double feed misinterpretation by adjusting motor torque and image processing based on thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic sensor is used to detect whether a single document is transferred or double feed occurs, then the number of documents can be detected, but a thick document such as a card can be erroneously detected as double feed of thin paper documents

Engineering Contradiction:

Improvedocument thickness detection accuracyVSAvoiddouble feed detection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The detection system is segmented into multiple independent detection units: an ultrasonic sensor for detecting the number of documents, a guide unit with imaging unit for detecting document thickness, and a control unit that integrates both detection results. This segmentation allows each unit to perform its specific function accurately without interference, resolving the contradiction between detecting document count and avoiding false double-feed detection for thick documents.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The guide unit acts as an intermediary between the ultrasonic sensor and the control unit. It receives the ultrasonic detection signal and provides additional thickness information through the imaging unit, mediating the detection process to distinguish between actual double-feed events and single thick documents, thereby improving both measurement precision and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a thickness of a document is not obtained, then the detection process is simple, but transfer of a thick document cannot be distinguished from double feed of thin documents

Engineering Contradiction:

Improvedetection system complexityVSAvoiddocument thickness measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The guide unit is designed with multi-functionality: it serves as both a mechanical guide for document conveyance and as a mounting structure for the imaging unit that detects document thickness. This universal design allows the system to obtain thickness measurements without adding separate complex structures, balancing device complexity with measurement precision requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The imaging unit replaces complex mechanical thickness measurement mechanisms with optical detection. By using image processing to determine document thickness from captured images, the system achieves precise thickness measurement without the mechanical complexity of physical measurement devices, resolving the contradiction between simplicity and accuracy.

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

Enables accurate detection of document thickness, preventing double feed errors and ensuring proper conveyance and image processing, especially for thick documents, thereby enhancing the reliability of imaging output.

Implementation Method 1

an ultrasonic sensor is used to detect whether a single document is transferred or double feed occurs

Methodology Applied

Scientific EffectUltrasonic wave propagation: Ultrasound

Data Source

PatentUS9674389B2Image unit with guide unit movable in direction perpendicular to conveyance path

Publication Date: 2017.06.06 PFU LTD

AI summary

A medium conveyance apparatus including a first unit on one side of a conveyance path of a sheet-shaped medium, a second unit on the other side of the conveyance path and facing the first unit, a guide unit that is provided at the second unit and that contacts the medium between the first and second unit to move the second unit in a direction of separating from the conveyance path, an imaging unit provided at one of the first and second unit, a reference plate whose image can be captured by the imaging unit and that is provided at the other of the first and second unit, and a detecting unit for detecting the medium in the conveyance path, the detecting unit being provided in the conveyance path at an upstream position of a reading position where the imaging unit reads the medium.