Non-Contact Optical Document Size Detection for Mixed Media
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Solution Overview
Problem
Conventional automatic document feeders struggle to accurately detect and select suitable paper sizes for printing, especially when dealing with mixed sizes, and often risk damaging documents due to contact-based detection methods.
Innovation Solution
A document processing device with a detecting module featuring a front-row detector and multiple rear-row detectors that operate in a non-contact, optical mode to determine the size of documents, allowing for the selection of appropriate paper cassettes without physical contact, using infrared beams and a look-up table to identify paper sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based detection methods (linkage rods and detectors) are used to determine original size, then size detection can be performed, but the originals may be damaged due to physical contact and squeezing
Solution Approach 1:
The patent replaces the mechanical linkage rod and detector system with an optical detection system using infrared transmitters and receivers. This substitution eliminates physical contact between the detection mechanism and the originals, thereby preventing damage while maintaining size detection capability. The infrared beams pass through the transfer channel and detect original positions without mechanical interaction.
Solution Approach 2:
The patent introduces infrared beams as an intermediary medium to transfer detection information. Instead of direct mechanical contact, the infrared energy acts as a mediator that carries size information from the originals to the detectors, enabling non-contact measurement and eliminating the harmful mechanical squeezing effect.
2Device complexity
If only two sets of linkage rods are provided for large and small papers, then hardware complexity is reduced, but the system cannot accurately detect mixed sizes of originals
Solution Approach 1:
The patent segments the detection system into multiple infrared transmitters and receivers positioned at different locations along the transfer channel. This segmentation allows the system to detect multiple size categories simultaneously by monitoring which detectors are triggered, enabling accurate detection of mixed sizes without requiring a single complex mechanical structure.
Solution Approach 2:
The infrared-based detection system serves multiple functions: it can detect various original sizes (A4, A5, B5, etc.), determine original positions, and identify mixed size conditions. This universal detection mechanism replaces the need for separate specialized linkage rods for each paper size, reducing hardware complexity while improving versatility.
3Ease of operation
If paper guide is pushed toward the stack of originals to determine size, then size classification is simplified, but only the largest original size can be detected in mixed size stacks
Solution Approach 1:
The patent performs preliminary detection by positioning multiple infrared transmitters and receivers along the transfer channel before the originals are fully processed. This preliminary arrangement allows the system to detect all original sizes in the stack simultaneously as they pass through, rather than sequentially pushing the paper guide to find the largest size, thereby capturing complete size information.
Solution Approach 2:
The patent transitions from a single-point detection approach (pushing paper guide to one position) to a multi-dimensional detection array with transmitters and receivers at various positions along the transfer channel. This spatial distribution across multiple dimensions enables simultaneous detection of different original sizes, providing complete size information for mixed stacks.
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
Enables accurate non-contact size detection and selection of suitable paper cassettes, preventing document damage and improving efficiency in handling documents of various sizes during the automatic document feeding process.
Implementation Method 1
an infrared transmitter and an infrared receiver corresponding to the transfer channel in a non-contact manner
Data Source
AI summary
A size determination method for a document processing device is provided. The document processing device includes an automatic document feeding module. The automatic document feeding module includes a support tray, an entrance and a detecting module. The detecting module includes a front-row detector and plural rear-row detectors. The size determination method includes following steps. Firstly, a document with plural originals is placed on the support tray and inserted into the entrance. Then, a selected original of the document is transported. When the selected original is detected by the front-row detector, the plural rear-row detectors are powered on. The selected original is continuously transported, and the plural rear-row detectors are operated in a detection mode. Then, a size of the selected original is determined according to detection results of the plural rear-row detectors and a transfer time of the selected original.