Inkjet Nozzle Malfunction Detection via Segmented Test Patterns
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Solution Overview
Problem
Existing image forming apparatuses require high-resolution image scanning devices to measure ink droplet hitting positions and deviations, leading to increased costs.
Innovation Solution
An image forming apparatus with a recording head and an ink-ejection-malfunction-nozzle detecting unit that uses test patterns with thin lines and blank lines to detect ink ejection malfunction nozzles without the need for high-resolution image scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution image scanning device (4800 dpi) is used to measure ink droplet hitting position and deviation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the nozzle array into multiple nozzle groups with different intervals (first interval and second interval). By printing test patterns from these segmented nozzle groups and analyzing the resulting bands, the system can detect malfunctioning nozzles without requiring high-resolution scanning. The segmentation allows standard-resolution scanners to distinguish between adjacent nozzle outputs.
Solution Approach 2:
The patent applies different interval configurations to different nozzle groups (first interval for some groups, second interval for others). This local differentiation in nozzle spacing creates distinct band patterns in the test output that can be detected by standard-resolution scanners, eliminating the need for high-resolution imaging while maintaining detection accuracy.
2Measurement precision
If a high-resolution image scanning device is used to detect ink ejection malfunction nozzles, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the nozzles into multiple groups with different intervals and uses this segmentation to create detectable patterns in test prints. By analyzing which bands are missing or abnormal in the printed output, the system can identify malfunctioning nozzles using standard-resolution scanning equipment, thereby reducing manufacturing costs while maintaining detection accuracy.
Solution Approach 2:
The patent changes the spatial parameter (interval) between nozzles in different groups to create distinguishable test patterns. By varying the interval parameter and analyzing the resulting band patterns at standard resolution, the system achieves accurate malfunction detection without requiring expensive high-resolution scanners.
3Manufacturing precision
If nozzles are arranged with small intervals to increase printing resolution, then printing quality is improved, but difficulty in detecting malfunction nozzles increases
Solution Approach 1:
The patent segments nozzles into groups with different intervals (first interval and second interval). This segmentation allows the system to print test patterns where bands from different nozzle groups can be distinguished even when nozzles are closely spaced for high-resolution printing. The different intervals create detectable spacing variations that enable malfunction detection without compromising printing resolution.
Solution Approach 2:
The patent introduces a new dimension for detection by using interval variation as a distinguishing feature. Instead of relying solely on high-resolution spatial imaging to detect malfunctions, the system uses the interval dimension to create detectable patterns that can be analyzed at standard resolution, thereby solving the detection difficulty associated with closely-spaced nozzles.
Data Source
AI summary
An ink-ejection-malfunction-nozzle detecting unit sets nozzle groups such that each nozzle group includes nozzles with a first interval, prints a first test pattern that includes first bands (including thin lines) corresponding to the nozzle groups, sets nozzle subgroups such that each nozzle subgroup includes nozzles with a second interval in each of the nozzle groups, prints a second test pattern that includes second bands (including thin blank lines) corresponding to the nozzle subgroups such that a correction process is performed for adjacent pixels of the thin blank lines, detects a first band including density defect in a scanned image of the first test pattern, detects a second band not including density defect in a scanned image of the second test pattern, correspondingly to the detected first band, and detects an ink ejection malfunction nozzle on the basis of the thin blank line in the detected second band.