Inkjet Nozzle Malfunction Detection with Overlapping Line Scans
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Solution Overview
Problem
Inkjet-type image forming apparatuses face challenges in accurately determining nozzle ejection malfunctions due to synchronization marks being improperly scanned when passing through gaps between adjacent sensor units of a line sensor, leading to inaccurate detection of ink ejection issues.
Innovation Solution
The apparatus incorporates a line sensor with multiple sensor units that partially scan a test pattern image, including a synchronization mark, allowing for precise determination of nozzle malfunctions by analyzing density distributions across overlapping scanning areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a line sensor with multiple sensor units is used to scan the test pattern image, then the scanning coverage is improved, but the synchronization mark may pass through gaps between sensor units causing improper scanning
Solution Approach 1:
The line sensor is divided into multiple sensor units with standardized widths that can be independently arranged. Each sensor unit scans a portion of the test pattern image, and the segmentation allows for flexible configuration while maintaining comprehensive coverage through overlapping scanning areas.
Solution Approach 2:
The synchronization mark is designed to pass through an overlapping section in the perpendicular direction to the sheet transportation direction. This dimensional approach ensures that the synchronization mark is captured by at least one sensor unit even when passing between adjacent units, resolving the gap problem through spatial redundancy.
2Ease of manufacture
If sensor units are arranged with standardized widths to reduce cost, then manufacturing cost is reduced, but gaps between units cause synchronization mark loss
Solution Approach 1:
The line sensor uses multiple sensor units of standardized widths that can be independently manufactured and assembled. This segmentation enables cost-effective production while maintaining functional integrity through the overlapping scanning arrangement.
Solution Approach 2:
The synchronization mark is positioned to pass through an overlapping section where scanning areas of adjacent sensor units intersect. By changing the spatial parameter of the synchronization mark position to utilize the overlapping region, the system ensures reliable detection without requiring expensive custom-designed continuous sensor arrays.
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 ensures accurate identification of ejection malfunction nozzles, enhancing the reliability of inkjet printing by correcting nozzle performance issues based on synchronization mark positions and density analysis.
Implementation Method 1
The line sensor is configured to scan a test pattern image printed on the sheet using the plural nozzles and generate a test pattern scanned image
Data Source
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AI summary
An inkjet recording unit ejects ink to a sheet using plural nozzles. A line sensor scans a test pattern image printed on the sheet using the plural nozzles. The test pattern image includes a synchronization mark formed by a predetermined reference position nozzle. The line sensor includes plural sensor units that partially scan the test pattern image respectively and generate plural partial test pattern scanned images. Scanning areas of the sensor units have an overlapping section. The synchronization mark is formed so as to pass through the overlapping section. An ejection malfunction determination unit determines positions corresponding to a part of the plural nozzles in the partial test pattern scanned image on the basis of a position of the synchronization mark, and determines whether a nozzle corresponding to the determined position is an ejection malfunction nozzle or not on the basis of a density at the determined position.