Inkjet Printer Nozzle Clogging Reduction via Row Segmentation
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Solution Overview
Problem
Inkjet printing methods for overprinting, such as those described in Japanese Patent No. 5629360, lead to nozzle clogging and discharge failures due to the continuous use of half the ink head for either base or image layer printing, resulting in unused nozzles drying out and requiring additional drying steps.
Innovation Solution
The implementation of an inkjet printer with a discharge head featuring two nozzle rows arranged in the primary scan direction, where both rows are used for both base and image ink printing, with a controller managing the printing process to alternate between nozzle rows, ensuring that only central nozzles are used for overprinting, reducing nozzle idle time and clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ink head is divided into upstream and downstream halves for overprinting with one-way feeding, then the base layer and image layer can be printed continuously without reverse feeding, but half of the nozzles remain unused during overprinting causing ink to dry and clog the discharge ports
Solution Approach 1:
The ink head is divided into first and second nozzle rows arranged in the primary scan direction, with each row containing nozzles for both base ink and image ink. This segmentation allows alternating use of different nozzle rows to ensure all nozzles remain active and prevent clogging while maintaining continuous one-way feeding for overprinting.
Solution Approach 2:
The printing process alternates between using the first nozzle row for base layer printing and the second nozzle row for image layer printing in a periodic manner. This periodic alternation ensures that nozzles in one row remain unused only briefly while the other row is active, preventing ink drying and clogging while maintaining high overprinting efficiency.
2Manufacturing precision
If a drying step using a heater is inserted between base layer and image layer printing, then color mixing is prevented, but the printing process time is increased and nozzle drying is accelerated
Solution Approach 1:
The system alternates between printing base layers and image layers using different nozzle rows, creating periodic intervals where nozzles remain active. This prevents the need for extended drying steps with heaters, as the alternating use of nozzles ensures ink remains fresh while still allowing sufficient time for color separation.
Solution Approach 2:
The nozzle rows are pre-configured with both base ink and image ink discharge capabilities, allowing the system to switch between printing modes without requiring intermediate drying steps. This preliminary configuration enables continuous printing while preventing color mixing through temporal separation of ink discharge.
3Manufacturing precision
If only central nozzles are used for overprinting, then color mixing between base and image inks is minimized, but the number of active nozzles is reduced
Solution Approach 1:
The nozzle rows are segmented into central nozzles for overprinting and end nozzles for edge printing. This segmentation allows the central nozzles to focus on precise overprinting with minimal color mixing, while the end nozzles handle edge areas where color mixing is less critical, thereby maximizing overall nozzle utilization.
Solution Approach 2:
Different regions of the nozzle rows are assigned different functions: central nozzles are optimized for precise overprinting with strict color separation, while end nozzles are used for edge printing where slightly more flexibility is acceptable. This local differentiation maximizes both print quality and nozzle utilization efficiency.
Data Source
AI summary
In an inkjet printer capable of performing an overprint process by feeding only in a first direction while reducing clogging of nozzles, a controller includes first, second and third controllers. The third controller instructs the first controller to perform a first image-printing scan, a first minute feed and a second image-printing scan without discharging an image ink from a first nozzle at an end portion of a first nozzle row in a first direction along a secondary scan direction; then performs a second minute feed of feeding a recording medium in the first direction along the secondary scan direction relative to a discharge head; and then instructs the second controller to perform a first base-printing scan, a first minute feed and a second base-printing scan without discharging a base ink from a second nozzle at an end portion of a second nozzle row in a second direction, opposite to the first direction, along the secondary scan direction.