Carriage Positioning Using Reference Pattern Detection
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Solution Overview
Problem
Existing image reading apparatuses face challenges in positioning the carriage at the home position without a dedicated sensor, leading to potential collisions and increased costs due to the need for additional components and space, especially in compact all-in-one MFPs.
Innovation Solution
An image reading apparatus that uses a carriage with a linear light source and image sensor, a reference pattern member, a nonvolatile storage unit, and a data-write controller to determine the carriage's location and move it to the home position based on stored location information, eliminating the need for a dedicated home position sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a home position sensor is used to detect the carriage position, then the carriage can be accurately positioned at the home position, but the device complexity and manufacturing cost increase
Solution Approach 1:
The carriage uses its own image sensor to detect the reference pattern on the platen glass, thereby determining its position. This self-service approach eliminates the need for separate home position sensors, reducing device complexity while maintaining positioning accuracy
Solution Approach 2:
A reference pattern is introduced as an intermediary element on the platen glass that enables the carriage to determine its position. The reference pattern serves as a mediator between the carriage's image sensor and the position detection function, allowing accurate positioning without additional sensors
2Measurement precision
If a home position sensor is installed, then the carriage positioning is improved, but the apparatus occupies more space
Solution Approach 1:
The existing image sensor on the carriage is utilized for dual purposes: capturing document images and detecting the reference pattern for position determination. This eliminates the need for dedicated home position sensors and their associated mounting spaces
Solution Approach 2:
The image sensor is made multi-functional by using it both for document image capture and for home position detection through reference pattern recognition. This universal usage eliminates redundant components and reduces the overall apparatus footprint
3Manufacturing precision
If the carriage is moved to read the reference pattern for shading correction, then accurate shading correction is achieved, but the positioning process becomes more complex
Solution Approach 1:
The functions of document image reading and reference pattern detection are merged into a single operation using the same image sensor. The carriage moves to positions where it can perform both functions, simplifying the control system by eliminating separate detection mechanisms
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 solution allows reliable positioning of the carriage at the home position without collisions, reduces component count and manufacturing costs, and conserves space, enhancing the compactness and efficiency of image reading systems.
Implementation Method 1
a linear light source that throws light onto the document sheet... an image sensor that receives light reflected from the document sheet
Implementation Method 2
The image sensor has a photoelectric conversion element that converts received light into an electrical signal
Data Source
AI summary
An image reading apparatus includes a carriage having mounted thereon a linear light source and an image sensor and a reference pattern member disposed at a reference position located toward the first direction from a home position. The current location of the carriage is judged relatively to first and second areas that are divided by a boundary defined in advance at a location toward the first direction from the reference position. The first area is located toward the first direction and the second area is located toward the second direction. Immediately after the power is turned ON, current location information indicating whether the carriage is currently located in the first area or the second area is read from the nonvolatile memory. The carriage is first moved to the reference position and then moved a predetermined distance in the second direction, so that the carriage is duly positioned at the home position.