Sheet Feeder Ultrasonic Sensor Multi-Feed Discrimination
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Solution Overview
Problem
Existing sheet feeders with ultrasonic sensors face difficulties in accurately distinguishing between different feeding states, such as multi-feed and sheet type, particularly when feeding thick plastic cards and thin regular papers, and are unable to determine sheet size effectively.
Innovation Solution
A sheet feeder system that includes an emitter and receiver for ultrasonic waves, with a controller processing reception intensities measured during specific time periods to determine the feeding state, allowing for discrimination between various feeding states, including multi-feed, by analyzing direct and diffracted wave components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ultrasonic sensor is used to detect sheet thickness, then the device structure remains simple, but the ability to accurately distinguish between different feeding states and sheet types deteriorates
Solution Approach 1:
The patent divides the detection process into two distinct time periods: a first period for measuring direct wave reception intensity and a second period for measuring diffracted wave reception intensity. This temporal segmentation allows the single sensor to gather multiple types of information sequentially, enabling accurate discrimination between different feeding states and sheet types without requiring multiple physical sensors.
Solution Approach 2:
The patent transitions from spatial differentiation (using multiple sensors) to temporal differentiation (using time-separated measurements). By measuring reception intensities at different time periods corresponding to different wave components, the system adds a time dimension to the detection process, allowing a single sensor to perform what would otherwise require multiple simultaneous sensors.
2Device complexity
If ultrasonic sensor measures only single reception intensity value, then the measurement process remains simple, but the ability to determine sheet size and detect multi-feed deteriorates
Solution Approach 1:
The patent segments the ultrasonic wave reception into two distinct components measured at different time periods: direct waves during the first period and diffracted waves during the second period. By analyzing both reception intensities separately, the system can determine sheet size from direct wave characteristics and detect multi-feed conditions from diffracted wave patterns, thereby preserving comprehensive information without overcomplicating the measurement process.
3Device complexity
If the sheet feeder cannot distinguish between thick plastic cards and thin regular papers, then the feeding control remains simple, but the accuracy of identifying actual feeding state deteriorates
Solution Approach 1:
The patent applies different analysis methods to different time periods: the first period measurement (direct wave) is used to assess sheet thickness characteristics, while the second period measurement (diffracted wave) is used to detect multi-feed conditions. This localized quality approach allows the system to accurately identify sheet type by focusing on the relevant temporal characteristics for each detection purpose.
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 system accurately determines the feeding state and sheet type, including the presence of multi-feed and skewing of plastic cards, enabling precise control and correction in document feeding processes.
Implementation Method 1
an emitter configured to emit ultrasonic waves, a receiver opposed to the emitter across the sheet guide, the receiver being disposed to face a second side of the sheet being fed along the sheet guide
Implementation Method 2
controlling the measurer to measure a first reception intensity of a first component of the ultrasonic wave received by the receiver during a first period of time, controlling the measurer to measure a second reception intensity of a second component of the ultrasonic wave received by the receiver during a second period of time after the first period of time
Data Source
AI summary
A sheet feeder includes a controller configured to control an emitter to emit an ultrasonic wave toward a target sheet being fed along a sheet guide, control a measurer to measure a first reception intensity of a first component of the ultrasonic wave received by a receiver during a first period of time, control the measurer to measure a second reception intensity of a second component of the ultrasonic wave received by the receiver during a second period of time, and determine a feeding state of the target sheet in a detectable area between the emitter and the receiver within the sheet guide, based on the first reception intensity and the second reception intensity.