Line-Head Inkjet Printing to Prevent Viscosity-Related Degradation
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Solution Overview
Problem
Line-head-type image forming apparatuses face challenges in preventing image quality degradation due to ink viscosity increase without requiring preliminary ink ejection, which can cause mechanical delays.
Innovation Solution
Implement a controller that manages nozzle ejection by performing substitutional ink ejection when a nozzle corresponding to a target pixel continues to eject ink in a predetermined line number, while adjacent nozzles either do not eject ink or adjust their ejection amount to mitigate ink viscosity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If preliminary ink ejection is performed to prevent image quality degradation due to ink viscosity increase, then image quality is improved, but printing is delayed and mechanical configuration complexity increases
Solution Approach 1:
The patent applies preliminary action by having adjacent nozzles perform substitutional ink ejection before the target nozzle becomes clogged due to continuous operation. This preventive measure maintains ink flow without requiring mechanical flushing mechanisms, thus improving image quality while avoiding printing delays associated with traditional preliminary ink ejection systems
2Manufacturing precision
If preliminary ink ejection is performed to prevent image quality degradation, then image quality is improved, but device complexity increases due to required mechanical configuration
Solution Approach 1:
The patent extracts the preliminary ink ejection function from mechanical flushing mechanisms and transfers it to the printing process itself through substitutional ejection. By using adjacent nozzles to perform ink ejection in place of the target nozzle, the system eliminates complex mechanical preliminary ejection configurations while maintaining image quality
Solution Approach 2:
The patent makes the adjacent nozzles perform multiple functions: their normal printing function and the additional function of substitutional ink ejection for preventing clogging. This multi-functionality eliminates the need for separate mechanical preliminary ejection systems, reducing device complexity while maintaining image quality
3Productivity
If a nozzle performs continuous ink ejection to maintain printing speed, then productivity is improved, but ink viscosity increase causes image quality degradation
Solution Approach 1:
The patent implements periodic action by alternately using target nozzles and adjacent nozzles for ink ejection. When a target nozzle has continuously ejected ink for a predetermined number of lines, the controller switches to adjacent nozzles for substitutional ejection. This periodic switching prevents ink viscosity increase in any single nozzle while maintaining continuous printing speed
Solution Approach 2:
The patent applies inversion by reversing the conventional approach: instead of one nozzle continuously ejecting ink and requiring periodic mechanical flushing, the system has multiple nozzles alternately performing ejection duties. This inverted approach maintains productivity while preventing viscosity-related quality degradation through distributed ejection responsibility
Data Source
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AI summary
An image forming apparatus (10) includes a line-head-type recording head (11), and a controller (75). The line-head-type recording head includes plural nozzles, and the recording head is configured to eject ink through the nozzles. The controller causes the recording head to eject ink and thereby performs printing of an image. Further, if a nozzle corresponding to a target pixel in the image performs ink ejection continuously in lines of a predetermined first line number, and one or both of two nozzles corresponding to both adjacent pixels to the target pixel does not/do not perform ink ejection continuously in lines of a predetermined second line number, then the controller causes the recording head to perform ink ejection of one or both of the two nozzles instead of ink ejection of the nozzle corresponding to the target pixel.