Automatic Document Feeder Multi-Feed Detection Sensor Unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automatic document feeders face malfunctions due to multi-feed issues, where documents are conveyed overlappingly, causing damage and requiring effective detection to prevent such occurrences.
Innovation Solution
An automatic document feeder equipped with a multi-feed detection sensor unit comprising ultrasonic sensors and a sensor control unit that detects and diagnoses faults in the sensor components, allowing for accurate separation and conveyance of documents by comparing output signals with predetermined thresholds and displaying fault information for user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-feed detection sensor unit is used to detect overlapping documents, then multi-feed malfunctions are prevented, but the device complexity increases due to additional sensor components and fault diagnosis requirements
Solution Approach 1:
The sensor unit is divided into distinct functional modules: transmission sensor, reception sensor, drive circuit, amplifier circuit, and comparator. Each module is independently testable through the fault diagnosis function, allowing targeted replacement rather than replacing the entire sensor unit. This segmentation reduces operational complexity while maintaining detection reliability.
Solution Approach 2:
The sensor control unit implements a feedback mechanism that continuously monitors sensor output signals and compares them against predetermined thresholds. When abnormalities are detected, the system automatically diagnoses which specific component (transmission sensor, reception sensor, drive circuit, amplifier circuit, or comparator) is faulty and notifies the user. This feedback system maintains high detection accuracy while simplifying maintenance through precise fault identification.
2Ease of repair
If fault diagnosis functionality is added to the sensor control unit, then maintenance time is reduced by identifying specific faulty components, but the device complexity increases due to additional diagnostic circuits and processing requirements
Solution Approach 1:
The sensor control unit performs self-diagnosis by automatically monitoring its own sensor components and identifying faults without external intervention. The system tests each component (transmission sensor, reception sensor, drive circuit, amplifier circuit, comparator) and autonomously determines which specific element is malfunctioning. This self-service capability significantly reduces maintenance time and complexity, as users only need to replace the identified faulty component rather than troubleshoot the entire sensor unit.
3Measurement precision
If ultrasonic sensors are used for multi-feed detection, then detection accuracy is maintained across documents of different colors and transmittances, but the reliability decreases when sensor components themselves become faulty and undetected
Solution Approach 1:
The system performs preliminary fault diagnosis by testing all sensor components before they are needed for actual document detection. The sensor control unit checks the transmission sensor, reception sensor, drive circuit, amplifier circuit, and comparator to ensure they are functioning correctly. This preliminary action prevents situations where undetected sensor faults could lead to inaccurate multi-feed detection, thereby maintaining both measurement precision and reliability.
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 multi-feed malfunctions by accurately detecting and diagnosing faults in the sensor components, reducing document damage and enabling the automatic document feeder to operate safely and efficiently.
Implementation Method 1
an ultrasonic sensor that is not affected by a color or a transmittance of a document is used as the transmission sensor and the reception sensor. An ultrasonic wave transmitted by the transmission sensor is received by the reception sensor
Implementation Method 2
An ultrasonic wave transmitted by the transmission sensor is received by the reception sensor and is converted into an electric signal, and the electric signal is output
Data Source
AI summary
The automatic document feeder includes a multi-feed detection sensor unit, a sensor control unit, and a control board on which the sensor control unit is mounted. The multi-feed detection sensor unit includes a transmission board on which a transmission sensor and a detection circuit of a drive current of the transmission sensor are mounted, a reception board on which a reception sensor and an amplifier circuit of a reception signal of the reception sensor are mounted, and a relay board on which a drive circuit of the transmission sensor is mounted. The sensor control unit stores first fault information indicating that the relay board is disconnected if the relay board is disconnected, stores second fault information indicating that the reception board is at fault if an output value of the amplifier circuit is equal to or less than a first threshold, stores third fault information indicating that the transmission board is at fault if the detection circuit does not detect the drive current, and stores fourth fault information indicating that the transmission sensor or the reception sensor is damaged if the output value of the amplifier circuit is equal to or less than a second threshold. If the fault information is stored, the sensor control unit transmits, to an image forming apparatus, an instruction signal for causing the fault information to be displayed.