Paper Conveyance Jam Detection via Analog Signal Rectification

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Solution Overview

Problem

Existing paper conveying apparatuses face challenges in accurately detecting jams due to short sound lengths generated, and peak detection circuits are not utilized for waveform deformation to enhance detection.

Innovation Solution

A paper conveying apparatus that includes an analog sound signal generator, an absolute value signal generator, a corrected signal generator for peak holding, and a digital converter to process analog sound signals into digital format for precise jam detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a peak detection circuit is used to detect the peak value of the measured sound signal, then the detection speed is improved, but the measurement precision deteriorates because the short sound length cannot be accurately detected within the processing interval

Engineering Contradiction:
Improvedetection speedVSAvoidjam detection precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing waveform deformation (rectification and smoothing) on the sound signal before detection. The rectification circuit converts the AC sound signal to a DC signal, and the smoothing circuit reduces fluctuations, preparing the signal in advance so that even short-duration jam sounds can be accurately detected within the processing interval.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the sampling interval is shortened to improve detection accuracy, then the measurement precision is improved, but the productivity deteriorates due to increased CPU processing load

Engineering Contradiction:
Improvejam detection precisionVSAvoidprocessing efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical/CPU-based signal processing system with electronic circuitry. The rectification circuit and smoothing circuit perform signal conditioning in the analog domain, eliminating the need for high-frequency sampling and reducing the CPU processing load while maintaining detection 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 jams even with short sound lengths and reduces CPU processing load by allowing longer sampling intervals, enabling the use of lower performance CPUs.

Implementation Method 1

a microphone 113, which detects a sound generated by the paper during conveyance of the paper, and generates a signal corresponding to the detected sound

Methodology Applied
Scientific EffectAcoustic transduction:

Data Source

PatentEP2799377B1Paper conveying apparatus
Publication Date: 2019.12.04 PFU LTD
  • EP2799377B1 patent drawingFigure 1
  • EP2799377B1 patent drawingFigure 2
  • EP2799377B1 patent drawingFigure 3

AI summary

A paper conveying apparatus (100, 200, 300, 400) includes an analog sound signal generator (141) for generating an analog sound signal corresponding to a sound generated by the paper during conveyance of the paper, a corrected signal generator (144, 444) for generating a signal acquiring the peak hold of the analog sound signal or a signal detecting the analog sound signal as a corrected signal, a digital converter (145) for sampling the corrected signal and converting the corrected signal to a digital format to generate a digital sound signal, and a sound jam detector (153) for determining whether a jam has occurred based on the digital sound signal.