Inkjet Recording Head Nozzle Malfunction Correction by Sheet Size
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Solution Overview
Problem
Inkjet-type image forming apparatuses face challenges in efficiently correcting multiple ink ejection malfunction positions during printing, particularly when printing on cut sheets, as the correction process cannot be completed in a short time due to the need to determine and correct pixel positions quickly, leading to high costs associated with using high-speed hardware.
Innovation Solution
The apparatus includes a recording head, a control unit, and a correction processing unit that determines and corrects ink ejection malfunction positions by setting targets for the correction process in advance, excluding non-used nozzles based on sheet size, and performing the correction process only for selected malfunction positions within a predetermined limit, using a test pattern to detect and prioritize malfunction positions by density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed hardware is used to perform correction process for multiple ink ejection malfunction positions, then the correction process can be completed in time, but the apparatus cost increases
Solution Approach 1:
The patent extracts and excludes malfunction positions that correspond to nozzles not used for the current sheet size from the correction process targets. By removing unnecessary correction operations (those for nozzles outside the active printing area), the system reduces the number of corrections needed without requiring high-speed hardware, thus resolving the contradiction between correction speed and apparatus cost.
Solution Approach 2:
The patent performs preliminary determination of malfunction positions and their correspondence to nozzles in advance, before the actual printing operation. By pre-identifying which malfunction positions require correction based on the sheet size and nozzle usage pattern, the system prepares a optimized correction list that avoids unnecessary real-time processing, enabling efficient correction without high-speed hardware.
2Manufacturing precision
If correction process is performed for all ink ejection malfunction positions, then printing quality is improved, but processing time exceeds the short time available
Solution Approach 1:
The patent applies local quality by differentiating which malfunction positions require correction based on their location and correspondence to actual nozzle usage. Instead of uniformly correcting all malfunction positions, the system selectively applies correction only to those positions that correspond to nozzles actually used for the current sheet size, optimizing both quality and time efficiency.
Solution Approach 2:
The patent performs partial correction by selecting only the necessary subset of malfunction positions for correction based on sheet size and nozzle usage. Rather than correcting all malfunction positions (excessive action), the system performs correction only where needed (partial action), achieving sufficient printing quality within the available time constraint.
Data Source
AI summary
In an image forming apparatus, a recording head ejects ink corresponding to an image to be printed, using arranged nozzles. A control unit determines nozzles corresponding to the image to be printed, correspondingly to a position of a print sheet, and causes the recording head to eject ink from the nozzles. A correction processing performs a correction process corresponding to each of ink ejection malfunction positions in the image. Further, the correction processing unit (a) sets the ink ejection malfunction positions as targets of the correction process in advance, and (b) excludes from the targets on the basis of a sheet size of the print sheet an ink ejection malfunction position corresponding to a nozzle that is not used for the print sheet among nozzles corresponding to the plural ink ejection malfunction positions and thereafter performs the correction process for the targets.