Image Capturer Movement Calculation Using Reflected Light Patterns
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately determining the conveying speed of a recording medium due to errors caused by similar patterns on the medium's surface and increased production costs associated with multiple light sources, as well as inaccuracies when the medium is inclined or the image capturer is not parallel to the conveying path.
Innovation Solution
An image forming apparatus that captures at least two images of the recording medium at different timings using a light source, calculates an index distance from the reflected light patterns, and determines the movement amount based on a ratio between the index distance and a reference distance, allowing for precise calculation of the conveying speed even when the image capturer's position relative to the medium changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pattern matching is used to detect conveying speed by capturing images at different timings, then the conveying speed can be specified, but erroneous detection occurs due to similar patterns on the recording medium surface
Solution Approach 1:
The patent extracts only the necessary light source function from the image capturer, separating it from the imaging function. The light source illuminates the recording medium to create reflected light patterns that encode movement information, while the image sensor captures these patterns. This extraction allows the system to focus on detecting movement through reflected light intensity changes rather than relying on complex pattern matching, thereby avoiding erroneous detection from similar patterns on the medium surface.
Solution Approach 2:
The patent changes the parameter being measured from spatial pattern recognition to temporal light intensity variation. Instead of analyzing the spatial arrangement of patterns in captured images, the system measures changes in reflected light intensity over time as the recording medium moves. This parameter change transforms the detection problem into one that is insensitive to pattern similarity, directly improving both measurement precision and reliability.
2Measurement precision
If multiple light sources are used to calculate movement amount, then detection accuracy improves, but production cost increases
Solution Approach 1:
The patent makes the single light source perform multiple functions: it illuminates the recording medium for movement detection, creates reflected light patterns that encode both position and movement information, and enables temporal analysis of light intensity changes. This multi-functionality eliminates the need for multiple specialized light sources while maintaining detection accuracy, directly reducing production costs without sacrificing measurement precision.
Solution Approach 2:
The reflected light from the recording medium itself serves as the detection signal. The medium's surface reflects the light source's illumination in a way that naturally encodes movement information through intensity variations over time. This self-service approach eliminates the need for additional active components like multiple light sources or complex sensors, reducing manufacturing complexity and cost while maintaining accurate movement detection.
3Measurement precision
If Fourier transform is used to process images for speed specification, then conveying speed can be calculated, but error increases when the recording medium is inclined with respect to the conveying path
Solution Approach 1:
The patent replaces the mechanical/optical system of capturing spatial images and performing Fourier transform analysis with a temporal measurement system. Instead of using image processing algorithms that are sensitive to medium inclination, the system directly measures reflected light intensity variations over time. This substitution of the detection mechanism eliminates the sensitivity to inclination that plagues image-based Fourier transform methods, improving reliability under various medium orientations.
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 approach enables accurate and precise calculation of the movement amount and conveying speed of the recording medium, reducing errors and production costs by using a single light source and correcting for positional changes between the image capturer and the medium.
Implementation Method 1
an image capturer that includes a light source and radiates light from the light source to capture the recording medium being conveyed at different timings to generate at least two images
Data Source
AI summary
An image forming apparatus includes: a conveying path on which a recording medium is conveyed; an image capturer that includes a light source and radiates light from the light source to capture the recording medium being conveyed at different timings to generate at least two images including a first image and a second image; and a movement amount calculator that calculates a movement amount of the recording medium between capturing timings of the first and second images, wherein the movement amount calculator: calculates an index distance which is a distance in a conveying direction of a pattern formed by reflected light from the recording medium; calculates a ratio between the index distance and a reference distance used for comparison with the index distance; and calculates a movement amount of the recording medium between the capturing timings of the first and second images.