Nozzle Detection via Interpolation in Liquid Discharging Apparatus
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Solution Overview
Problem
Existing liquid discharging apparatuses face challenges in accurately detecting defective nozzles due to high memory and processing time requirements, and are prone to errors from disturbances like magnification, skew, and vibration, especially when using scanners with lower resolution.
Innovation Solution
A liquid discharging apparatus with a conveying unit, a liquid discharging head, a scanner, and a chart generating unit that uses a defective nozzle detection chart with lines aligned in the sub-scanning direction, performing an interpolating process on pixel values to detect nozzle positions where the differential of the interpolation function is zero, and utilizing a mean value of pixels over multiple periods to account for vibrations and skew.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanned data and ideal data are converted into high-resolution data by interpolation to detect defective nozzles, then measurement precision is improved, but memory usage and processing time increase
Solution Approach 1:
The patent segments the data processing by applying interpolation only to specific scan line data that requires high-resolution analysis for defective nozzle detection, rather than converting the entire scanned image to high resolution. This selective approach maintains detection accuracy while reducing the volume of data requiring intensive processing, thereby decreasing processing time and memory usage.
Solution Approach 2:
The patent applies partial action by using interpolation only where necessary - specifically for analyzing scan lines that correspond to nozzle positions - rather than applying it uniformly across the entire image. This partial application of the interpolation technique achieves the required measurement precision for defective nozzle detection without the computational overhead of processing the complete image at high resolution.
2Measurement precision
If scanned data is converted into high-resolution data by interpolation to detect defective nozzles, then measurement precision is improved, but memory usage increases
Solution Approach 1:
The patent segments the data processing by applying interpolation only to specific scan line data that requires high-resolution analysis for defective nozzle detection, rather than converting the entire scanned image to high resolution. This selective approach maintains detection accuracy while reducing the volume of data requiring intensive processing, thereby decreasing processing time and memory usage.
Solution Approach 2:
The patent applies partial action by using interpolation only where necessary - specifically for analyzing scan lines that correspond to nozzle positions - rather than applying it uniformly across the entire image. This partial application of the interpolation technique achieves the required measurement precision for defective nozzle detection without the computational overhead of processing the complete image at high resolution.
3Measurement precision
If defective nozzles are determined by comparison with ideal data, then measurement precision is improved, but reliability decreases under disturbances like magnification, skew, and vibration
Solution Approach 1:
The patent changes the detection parameters by using actual scan line data from the scanned image directly, rather than comparing against ideal theoretical data. By adjusting to work with real-world scanned data that may contain magnification, skew, or vibration effects, the system maintains reliability under various disturbances while still achieving accurate defective nozzle detection through targeted interpolation analysis.
Data Source
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AI summary
A liquid discharging apparatus (1) includes a liquid discharging head (220) including nozzles arranged linearly and configured to discharge liquid onto a recording medium (P) conveyed by a conveying unit (210); a scanner (231, 232) installed in such a manner that a main-scanning direction of the scanner (231, 232) is aligned with a direction in which the nozzles of the liquid discharging head (220) are arranged; a chart generating unit (101) configured to generate a defective nozzle detection chart (C) in which lines (L) in a sub-scanning direction corresponding to the respective nozzles of the liquid discharging head (220) are arranged; and a position detecting unit (102) configured to perform an interpolating process on pixel values of a plurality of pixels around a line position detected from pixel values of scanned data of the defective nozzle detection chart (C) scanned by a scanner (231, 232), and detect a position where a differential of an interpolation function derived from the interpolating process is zero, as a line position.