Ultrasonic Sensor Shielding for Double-Feed Detection Accuracy
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Solution Overview
Problem
In sheet conveyance apparatuses, especially in downsized image processing devices, ultrasonic double-feed detection sensors are prone to erroneous double-feed determinations due to external interference and noise, which complicates accurate sheet conveyance and reading processes.
Innovation Solution
A conductive shield member is strategically positioned between the ultrasonic sensor receiver and the exterior of the sheet conveyance apparatus, covering the receiver in the sheet-face perpendicular direction to shield against external influences and noise, ensuring accurate double-feed detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sheet conveyance apparatus is downsized to save space, then the device compactness is improved, but the ultrasonic sensor easily receives external interference and noise causing erroneous double-feed detection
Solution Approach 1:
A conductive shield member is introduced as an intermediary component between the ultrasonic sensor receiver and the external environment. This shield member blocks external noise and interference from reaching the receiver, thereby maintaining detection accuracy while allowing the device to remain compact. The shield acts as a mediator that protects the sensitive receiver without requiring increased device size for isolation.
2Length of stationary object
If the distance from the ultrasonic sensor to the exterior is reduced due to downsizing, then the device compactness is improved, but the sensor receives more external interference causing erroneous determination
Solution Approach 1:
The conductive shield member serves as a protective intermediary positioned between the receiver and the device exterior. It blocks harmful external factors such as noise and interference from reaching the sensor, enabling the receiver to be placed closer to the exterior without compromising detection reliability.
3Measurement precision
If the detection signal is made weaker to detect double-feed accurately, then the detection sensitivity is improved, but the signal receives more noise influence causing erroneous determination
Solution Approach 1:
The conductive shield member acts as a protective barrier that isolates the receiver from external noise sources. This allows the system to use weaker detection signals with higher sensitivity for double-feed detection, as the shield prevents noise from overwhelming the weak signal, thereby maintaining both sensitivity and accuracy.
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 conductive shield member effectively prevents noise interference, enhancing the accuracy of double-feed detection and reducing erroneous determinations, even in compact device designs, thereby improving the reliability of sheet conveyance and reading processes.
Implementation Method 1
a transmitter that transmits an ultrasonic wave having a predetermined frequency; and a receiver that receives the ultrasonic wave
Implementation Method 2
the shield member is disposed between the housing and the receiver in a sheet-face perpendicular direction at an ultrasonic-irradiation position of the sheet being conveyed, the shield member covering an entirety of the receiver in plan view in the sheet-face perpendicular direction
Data Source
AI summary
Provided is a sheet conveyance apparatus armored with a housing, the sheet conveyance apparatus includes: a sheet conveyor that feeds a sheet to a downstream side in a direction of conveyance; a conveyance guide that guides the sheet to be conveyed; an ultrasonic sensor that detects the sheet guided by the conveyance guide; and a shield member that is conductive, wherein the ultrasonic sensor includes: a transmitter that transmits an ultrasonic wave having a predetermined frequency; and a receiver that receives the ultrasonic wave, the transmitter and the receiver are arranged along the conveyance guide, and the shield member is disposed between the housing and the receiver in a sheet-face perpendicular direction at an ultrasonic-irradiation position of the sheet being conveyed, the shield member covering an entirety of the receiver in plan view in the sheet-face perpendicular direction.