Image Scanner Pressure Plate Angle Detection
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Solution Overview
Problem
Existing image scanning apparatuses face challenges in accurately detecting the size of originals, particularly when scanning thick documents or under ambient light conditions, leading to erroneous detection due to limited brightness differences and increased manufacturing costs associated with high-accuracy sensors.
Innovation Solution
An image scanning apparatus with a pressure plate that includes first and second angle detectors, emitting light and recording reflected light distributions at different angles to detect the pressure plate's closed state and ambient light effects, allowing for accurate original width detection without expensive sensors by using combined distribution data and threshold adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If use of expensive sensors capable of detecting the opened-closed angle of the pressure plate at high accuracy is adopted, then measurement precision of original size is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive high-accuracy angle detection sensors with a combination of ordinary sensors and software-based angle calculation. The system uses detection values from ordinary sensors (which detect pressure plate state changes) combined with timing information to calculate the angle, thereby achieving accurate angle detection without expensive hardware sensors.
Solution Approach 2:
The patent substitutes a mechanical/optical sensing system (expensive angle sensors) with an information processing system. By using detection values from ordinary sensors combined with timing data from a timer, the system calculates the pressure plate angle through software processing, replacing the need for specialized mechanical angle detection hardware.
2Measurement precision
If reading is performed when the pressure plate is in a semi-open state to utilize brightness difference, then original width detection accuracy is improved, but measurement precision deteriorates when the pressure plate cannot be closed sufficiently due to thick originals
Solution Approach 1:
The patent dynamically adjusts the pressure plate angle based on the original thickness. For thick originals that prevent full closing, the system detects the actual angle reached and performs reading at that angle. The timer measures the time from opening to current position, allowing angle calculation and adaptive reading performance without requiring the pressure plate to reach a fixed closed position.
Solution Approach 2:
The patent changes the reading timing parameter based on the pressure plate's actual state. Instead of reading only at a fixed closed position, the system reads when the pressure plate reaches any detectable state, using the timer-measured angle information to compensate. This parameter adaptation ensures reliable detection across varying original thicknesses.
3Ease of operation
If the pressure plate is positioned at a certain angle or greater to facilitate reading, then ease of operation is improved, but measurement precision deteriorates due to ambient light affecting reading
Solution Approach 1:
The patent uses feedback from the timer and angle detection to control the reading operation. The system continuously monitors the pressure plate angle through timing measurements and only performs reading when the angle is within the optimal range (smaller than the predetermined angle). This feedback mechanism prevents reading when ambient light would interfere while maintaining ease of operation.
Solution Approach 2:
The patent performs preliminary angle detection and timing measurement before initiating the reading operation. By measuring the time from pressure plate opening and calculating the angle in advance, the system ensures reading only occurs when the pressure plate is at the correct angle, preventing ambient light interference before it can affect measurement 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
This configuration reduces erroneous detection of original size and effectively removes ambient light effects, ensuring accurate size detection without increasing manufacturing costs through the use of advanced sensor technology.
Implementation Method 1
causing light to be emitted to the original and recording a distribution of reflected light of the emitted light
Data Source
AI summary
An image scanning apparatus performs operations including: upon detection of a first angle, causing light to be emitted to an original and recording a distribution of reflected light of the emitted light as first read data; upon elapse of a predetermined time from detection of a second angle, causing light to be emitted to the original and recording a distribution of reflected light of the emitted light as second read data; detecting a closed state of a pressure plate based on the second read data; and upon determination of an angle of the pressure plate with respect to the platen being equal to or smaller than a third angle smaller than the second angle in the detection of the closed state, detecting a width of the original in an opening-closing direction of the pressure plate based on a difference between the first and second read data.