Capacitive Sheet Detection Device Using Dynamic Scanning
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Solution Overview
Problem
Existing sheet detection devices have limited freedom and precision in detecting sheet size due to the design concept that only allows for 'existing' or 'non-existing' detection stages based on the number of sensing regions, which restricts the detectable sheet size and usage.
Innovation Solution
A sheet detection device with a sheet guiding component, conductor elements, and sensing elements that generate varying capacitance values as the sensing element moves along a direction, allowing precise detection of sheet size based on capacitance changes, even when the sheet guiding component abuts against the sheet at any position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensing regions are designed to detect sheet size, then detection coverage is improved, but device complexity and number of electrically connected components increase
Solution Approach 1:
The sensing element is divided into multiple sensing regions that are not electrically connected to each other, allowing each region to independently detect sheet presence while collectively providing comprehensive size detection coverage
Solution Approach 2:
The patent transitions from detecting only sheet presence/absence to detecting continuous sheet size information by utilizing the movement of the sheet guiding component across multiple sensing regions, adding a spatial dimension to the detection capability
2Measurement precision
If sensing regions are arranged to cover all possible sheet sizes, then detection precision is improved, but the number of sensing regions and electrical connections increases
Solution Approach 1:
The sheet guiding component is designed to move between initial and threshold positions, dynamically scanning across the sheet and activating different sensing regions based on sheet size, replacing static multiple sensors with a dynamic single sensor approach
Solution Approach 2:
The movement of the sheet guiding component creates a temporal sequence of sensing element positions that effectively copies the function of multiple stationary sensing regions, reducing hardware complexity while maintaining detection precision
3Device complexity
If the sensing element detects only existing or non-existing sheet, then device simplicity is maintained, but detection freedom and precision are limited
Solution Approach 1:
The capacitance sensing processing unit processes signals from multiple sensing regions and the movement position of the sheet guiding component to generate precise sheet size detection results, adding intelligent processing to simple hardware
Solution Approach 2:
The system utilizes changes in capacitance values as the sensing element moves across different positions relative to the sheet, converting physical position and sheet dimensions into measurable electrical parameter variations for precise detection
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 device enhances the freedom and precision of sheet size detection by using capacitance changes to determine the sheet size, enabling accurate measurement regardless of the sheet's position and size, thereby overcoming the limitations of previous designs.
Implementation Method 1
A first overlapping portion between the first conductor element and the first sensing element correspondingly generates a first capacitance value, and the first capacitance value changes gradually corresponding to movement of the first sensing element along the first direction
Data Source
AI summary
A sheet detection device includes a sheet guiding component, a conductor element and a sensing element. The sheet guiding component is disposed in a sheet tray and movable between an initial position and a threshold position along a first direction. The conductor element is disposed in the sheet tray, and is conductor continuously extended and disposed correspondingly between the initial position and the threshold position. The sensing element is disposed on and moved with the sheet guiding component, and is disposed in spaced with the conductor element and overlaps with at least a part of the conductor element. An overlapping portion between the conductor element and the sensing element correspondingly generates a capacitance value, and the capacitance value changes gradually corresponding to the movement of the sensing element along the first direction.