Inkjet Nozzle Correction Prioritization for Cut-Sheet Printing
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Solution Overview
Problem
Existing image forming apparatuses face challenges in efficiently correcting ink ejection malfunctions during printing on cut sheets due to the need for high-capacity memory to store multiple malfunction positions, leading to increased costs and incomplete software-based correction processes.
Innovation Solution
An image forming apparatus that includes a recording head, a control unit, and a correction processing unit to determine and correct ink ejection malfunctions using hardware processes, preferentially addressing non-ejection issues over ink ejection deviations by printing test patterns and analyzing scanned images to identify and correct malfunction positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-based correction process is used for ink ejection malfunction, then correction can be performed, but the correction process cannot be finished in time due to processing speed limitations
Solution Approach 1:
The patent replaces the software-based correction process with a hardware-based correction process. Specifically, a correction processing unit with a correction lookup table is introduced to perform correction calculations in hardware, which significantly increases the processing speed and ensures the correction process can be completed within the required time frame while maintaining reliability.
2Speed
If high-speed hardware correction processing is used, then correction speed is improved, but large capacity memory device is required to store malfunction positions, resulting in high apparatus cost
Solution Approach 1:
The patent applies local quality by creating a correction lookup table that stores correction values only for specific malfunction positions and patterns. Instead of storing all possible malfunction data, the system selectively stores correction information for commonly occurring malfunction positions, thereby reducing memory requirements while maintaining high-speed hardware correction processing.
3Reliability
If correction process is performed for all ink ejection malfunction positions, then comprehensive correction is achieved, but processing time exceeds available time from sheet position determination to ink ejection
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing correction values in a correction lookup table before actual printing occurs. When a malfunction is detected, the system simply retrieves the pre-computed correction values from the lookup table based on the malfunction position, rather than performing complex correction calculations in real-time. This ensures comprehensive correction while completing the process within the available time frame.
Data Source
AI summary
A control unit 81 determines nozzles corresponding to an image to be printed, correspondingly to a position of a print sheet, and causes a recording head to eject ink from its nozzles. A correction processing unit 83 performs a correction process corresponding to each of plural ink ejection malfunction positions in the aforementioned image. Further, the correction processing unit 83 prints a test pattern using the recording head 1a, 1b, 1c or 1d, determines the ink ejection malfunction positions and ink ejection malfunction types on the basis of a scanned image of the test pattern, and performs the correction process such that the ink ejection malfunction of which the ink ejection malfunction type is non ejection is preferentially performed than the ink ejection malfunction of which the ink ejection malfunction type is ink ejection deviation.