Inkjet Head Nozzle Defect Compensation via Forced Ejection
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Solution Overview
Problem
Existing image recording apparatuses face challenges in effectively correcting image defects caused by adjacent defective nozzles, leading to insufficient ink amount or dot size, resulting in stripe unevenness, especially when two defective nozzles are adjacent, which can prevent line drawings from being recorded if a defective nozzle is made to eject no ink during non-ejection correction processing.
Innovation Solution
An image recording apparatus with a detection unit to identify defective nozzles, a correction processing unit to suspend the output of defective nozzles, and a selection unit to choose a 'forced recording element' from defective nozzles, allowing it to continue ink output, thereby improving image quality by compensating for defective nozzles and maintaining ink flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output of all defective nozzles is suspended during non-ejection correction processing, then the occurrence of stripe unevenness is reduced, but the ink amount and dot size become insufficient, causing image defects
Solution Approach 1:
The patent applies local quality by differentiating the treatment of defective nozzles based on their specific conditions. Instead of uniformly suspending all defective nozzles, the system selectively suspends only those defective nozzles that do not cause image defects when forced to eject, while allowing other defective nozzles to continue ejection. This localized differentiation resolves the contradiction by maintaining ink flow where necessary while correcting stripe unevenness where appropriate.
Solution Approach 2:
The patent inverts the conventional approach by not automatically suspending all defective nozzles, but rather forcing defective nozzles to eject and only suspending them when image defects occur. This inversion of the suspension logic allows the system to maintain ink flow from defective nozzles as the default state, preventing ink amount deficiency, while still achieving stripe unevenness correction through selective suspension based on actual image defect occurrence.
2Reliability
If a defective nozzle is made to eject no ink during non-ejection correction processing, then stripe unevenness is suppressed, but line drawings cannot be recorded when the defective nozzle corresponds to the line drawing
Solution Approach 1:
The patent applies local quality by making the suspension decision specific to each defective nozzle based on its individual impact on image quality. The system evaluates whether suspending a particular defective nozzle would cause line drawing loss, and only suspends those that do not cause such loss. This localized evaluation resolves the contradiction by preserving line drawing integrity while suppressing stripe unevenness in appropriate cases.
Solution Approach 2:
The patent inverts the conventional suspension approach by forcing defective nozzles to eject as the default and only suspending them when image defects are detected. This inversion ensures that line drawings are preserved by maintaining defective nozzle ejection, while stripe unevenness is suppressed through selective suspension based on actual image defect occurrence, thus resolving the contradiction between the two opposing requirements.
3Reliability
If the output densities of normal adjacent nozzles are increased to compensate for defective nozzles, then stripe unevenness is corrected, but sufficient ink amount and dot size cannot be obtained when two defective nozzles are adjacent
Solution Approach 1:
The patent applies local quality by differentiating the treatment based on the spatial distribution of defective nozzles. When two defective nozzles are adjacent, the system recognizes that increasing adjacent normal nozzle output densities is insufficient and selectively forces at least one defective nozzle to eject instead of suspending it. This localized adaptation resolves the contradiction by maintaining adequate ink amount in cases of adjacent defective nozzles while still achieving stripe unevenness correction in other scenarios.
Data Source
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AI summary
A method for controlling an image recording apparatus includes: detecting a defective recording element out of a plurality of recording elements on a recording head for recording an image on a recording medium; performing a correction processing including suspension of an output of the defective recording element and increase of an output of a recording element at least adjacent to the defective recording element according to a detection result; determining whether or not an image defect is caused in the image by the suspension of output of the defective recording element, before performing the correction processing, according to the detection result; selecting a forced recording element that is forced to output ink out of defective recording elements when it is determined that the image defect is caused; and suspending the output of the defective recording element other than the forced recording element when the forced recording element is selected.