Inkjet Head Correction via Sheet-Type Threshold Comparison
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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 increased costs due to the need for high-speed hardware, which complicates the correction process during printing on cut sheets.
Innovation Solution
An image forming apparatus with a recording head, control unit, and correction processing unit that prints a test pattern, determines ink ejection malfunction positions, calculates droplet hit position deviations, and compares these deviations to threshold values based on print sheet type to decide whether to perform corrections, thereby optimizing the correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed hardware is used to correct many ink ejection malfunction positions, then correction capability is improved, but apparatus cost increases
Solution Approach 1:
The patent changes the parameter of correction necessity by introducing a determination process that evaluates whether correction is actually needed based on malfunction position and image characteristics. This selective correction approach maintains reliability for necessary corrections while avoiding unnecessary processing that would require high-speed hardware, thus reducing apparatus cost.
Solution Approach 2:
The patent applies partial action by performing correction processing only for malfunction positions that are determined to be necessary, rather than correcting all malfunction positions. This selective approach reduces the correction load and allows the use of standard-speed hardware instead of expensive high-speed hardware, while still maintaining adequate correction capability for critical cases.
2Reliability
If correction process is performed for many ink ejection malfunction positions, then correction completeness is improved, but processing time increases
Solution Approach 1:
The patent changes the parameter of correction necessity by introducing a determination process that evaluates whether correction is actually needed. This selective correction approach maintains completeness for necessary corrections while reducing overall processing time by skipping unnecessary corrections.
Solution Approach 2:
The patent applies partial action by performing correction processing only for malfunction positions that are determined to be necessary, rather than correcting all malfunction positions. This reduces the total number of correction operations, thereby decreasing processing time while maintaining adequate correction completeness for critical malfunction positions.
3Productivity
If pixel determination and correction process are performed quickly, then real-time correction is achieved, but correction accuracy may be compromised
Solution Approach 1:
The patent applies preliminary action by performing a determination process before correction to identify which malfunction positions actually require correction. This pre-screening step enables the system to focus processing resources on critical cases, achieving both speed (by avoiding unnecessary corrections) and accuracy (by thoroughly processing only the necessary cases).
Data Source
AI summary
A control unit determines nozzles corresponding to the image to be printed and causes a recording head to eject ink from the nozzles. A correction processing unit performs a correction process corresponding to each of ink ejection malfunction positions in the image. The correction processing unit (a) prints a test pattern using the recording head, (b) determines the ink ejection malfunction positions on the basis of a scanned image of the test pattern, (c) determines a droplet hit position deviation amount of the ink at each of the ink ejection malfunction positions, and (d) determines a print sheet type of the print sheet, performs comparison between the droplet hit position deviation amount and a threshold value set for the print sheet type, and determines whether the correction process should be performed to the ink ejection malfunction position or not on the basis of a result of the comparison.