Inkjet Head Malfunction Correction via Selective Droplet Sizing
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Solution Overview
Problem
Inkjet-type image forming apparatuses face challenges in efficiently correcting multiple ink ejection malfunction positions within a short time, leading to high costs due to the need for high-speed hardware, which is not feasible for all correction processes.
Innovation Solution
The apparatus includes a control unit and correction processing unit that determines and prioritizes ink ejection malfunction positions by printing test patterns with varying ink droplet sizes, identifying preferential malfunction positions, and performing correction processes only on those, thereby optimizing the correction process within the given time frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed hardware is used to perform correction processes for many ink ejection malfunction positions, then the correction capability is improved, but the apparatus cost increases
Solution Approach 1:
The patent applies partial action by performing correction processes only for preferential malfunction positions (those detected with both small and large ink droplet sizes) rather than all detected malfunction positions. This selective approach reduces the number of correction operations required, allowing standard hardware to handle the reduced workload without needing expensive high-speed hardware, thus resolving the contradiction between correction capability and apparatus cost
Solution Approach 2:
The patent changes the parameter of ink droplet size to differentiate between preferential and non-preferential malfunction positions. By printing test patterns with both small and large ink droplet sizes and comparing detection results, the system identifies which malfunction positions require correction. This parameter-based classification enables selective correction with standard hardware capabilities
2Manufacturing precision
If correction processes are performed for all ink ejection malfunction positions, then the printing quality is improved, but the correction time exceeds the available short time window
Solution Approach 1:
The patent performs correction processes only for preferential malfunction positions that are detected with both small and large ink droplet sizes, rather than correcting all detected malfunction positions. This partial correction approach maintains acceptable printing quality by addressing the most significant malfunction positions while completing the correction process within the short time window between sheet position determination and ink ejection
Solution Approach 2:
The patent uses feedback from test pattern printing and scanning to identify preferential malfunction positions. By printing test patterns with different ink droplet sizes and scanning the results, the system gathers information about which malfunction positions consistently appear across different conditions. This feedback mechanism enables the system to prioritize correction for the most critical positions, ensuring quality improvement within time constraints
Data Source
AI summary
In image forming apparatus, a control unit determines nozzles corresponding to the image to be printed, correspondingly to a position of a print sheet, and causes a recording head to eject ink from the nozzles. A correction processing unit performs a correction process corresponding to each of plural ink ejection malfunction positions in the image. If the number of the ink ejection malfunction positions detected with a predetermined ink droplet size exceeds a predetermined upperlimit value, the correction processing unit prints a test pattern using the control unit with an ink droplet size larger than the predetermined ink droplet size, determines as a preferential ink ejection malfunction position an ink ejection malfunction position that ink ejection malfunction is also detected in the test pattern on the basis of a scanned image of the test pattern, and preferentially performs the correction process for the preferential ink ejection malfunction position.