Inkjet Recording Head Density Anomaly Correction via Pixel Neighborhood Analysis
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Solution Overview
Problem
In inkjet image forming apparatuses, especially those with automatic centering functions, the correction process for density anomalies caused by ink ejection order malfunctions is hindered, leading to issues like blank or black lines in printed images.
Innovation Solution
The image forming apparatus includes a recording head, a control unit, and a correction processing unit. The control unit determines the nozzles corresponding to the print sheet position, and the correction processing unit performs a correction process for density anomalies after gradation, based on the densities of periphery pixels within a predetermined distance from the target pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automatic centering function is used to adjust ink ejection position, then positioning accuracy is improved, but correction process for density anomalies cannot be performed
Solution Approach 1:
The correction process is segmented into two independent stages: first determining correction coefficients based on ejection order patterns, then applying corrections to pixel values. This allows the correction process to function independently of the automatic centering function while maintaining both positioning accuracy and anomaly correction capability.
Solution Approach 2:
The system performs preliminary determination of correction coefficients before the actual printing process. By pre-calculating correction values based on ejection order patterns and storing them in lookup tables, the system enables correction processing without interfering with the automatic centering function's real-time positioning adjustments.
2Manufacturing precision
If correction process is performed for density anomalies, then print quality is improved, but processing time increases
Solution Approach 1:
Correction coefficients are determined in advance based on ejection order patterns before the actual printing occurs. By pre-calculating and storing correction values in lookup tables, the system avoids time-consuming real-time calculations during printing, thus improving print quality without significantly increasing processing time.
Solution Approach 2:
The system creates a lookup table that copies and stores pre-calculated correction coefficients for different ejection order patterns. During printing, the system simply retrieves the appropriate correction values from this pre-generated table rather than calculating them in real-time, thereby maintaining high print quality while reducing processing time.
3Manufacturing precision
If correction coefficient is determined based on ejection order pattern, then density anomaly correction is improved, but device complexity increases
Solution Approach 1:
The correction processing is segmented into distinct functional blocks: ejection order pattern determination, correction coefficient lookup, and pixel value correction. This modular approach simplifies the overall system by dividing the complex correction process into manageable, independent stages that can be implemented using standard processing units.
Solution Approach 2:
The system uses lookup tables to store pre-calculated correction coefficients for different ejection order patterns. Instead of implementing complex real-time calculation algorithms, the system copies and retrieves pre-computed correction values from memory, significantly reducing the computational complexity and hardware requirements while maintaining accurate density anomaly correction.
Data Source
AI summary
An image forming apparatus includes a recording head, a control unit, and a correction processing unit. The recording head is configured to eject ink corresponding to an image to be printed, using nozzles. The control unit is configured to determine nozzles corresponding to the image to be printed, correspondingly to a position of a print sheet, and cause the recording head to eject ink from the nozzles. The correction processing unit is configured to perform for the image after gradation process a correction process corresponding to density anomaly that occurs due to an ejection order of the nozzles. Further, the correction processing unit performs the correction process for a density of a target pixel that the density anomaly occurs in the image after gradation pixel, on the basis of a total of densities of periphery pixels within a predetermined distance from the target pixel.