Inkjet Printhead Nozzle Failure Compensation via Periodic Elevated Droplets
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Solution Overview
Problem
Existing methods for compensating failed or incorrectly printing nozzles in inkjet printheads often result in print defects, such as white lines, and can lead to overloading and failure of compensation nozzles, limiting the achievable color space and print quality.
Innovation Solution
A method that involves using neighboring nozzles to print compensation droplets with an elevated volume compared to the maximum print droplet volume, defining a frequency for the creation of these droplets, and ensuring a minimum separation between them to effectively compensate for failed nozzles without overloading adjacent nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If compensation nozzles print with maximum print droplet volume to compensate for failed nozzles, then print quality is improved by closing white lines, but the compensation nozzles become overloaded and fail themselves
Solution Approach 1:
The patent applies periodic action by defining a frequency for creating compensation droplets that is lower than the maximum droplet creation frequency. This means compensation droplets are printed at intervals rather than continuously, allowing the compensation nozzle to rest and recover between droplet ejections. This periodic operation prevents the nozzle from becoming overloaded and failing, while still achieving sufficient compensation coverage to close white lines in the printed image.
Solution Approach 2:
The patent implements partial action by using elevated compensation droplet volumes that exceed the maximum print droplet volume only when necessary for compensation, rather than continuously operating at maximum capacity. The compensation droplet volume is increased above the maximum print droplet volume to ensure adequate coverage, but this excessive volume is applied selectively at defined frequencies rather than continuously, balancing compensation effectiveness with nozzle reliability.
2Manufacturing precision
If compensation droplets are printed with elevated volume to effectively close white lines, then compensation effectiveness is improved, but the risk of compensation nozzle failure increases
Solution Approach 1:
By defining a frequency for compensation droplet creation that is lower than the maximum droplet frequency, the system allows periodic recovery intervals for the compensation nozzle. This reduces the cumulative stress and thermal load on the nozzle, thereby lowering the risk of failure while maintaining adequate compensation effectiveness through elevated droplet volumes at these periodic intervals.
Solution Approach 2:
The patent changes the parameter of droplet volume by using elevated compensation droplet volumes that exceed the maximum print droplet volume. This parameter change enables more effective white line closure with fewer droplets, reducing the overall operational burden on the compensation nozzle and thereby lowering failure risk while maintaining compensation effectiveness.
3Manufacturing precision
If compensation droplets are printed at high frequency to maximize coverage, then white line closure is improved, but the compensation nozzle becomes overloaded
Solution Approach 1:
The system defines a frequency for compensation droplet creation that is deliberately kept below the maximum droplet creation frequency of the printhead. This periodic operation with intervals allows the compensation nozzle to recover between droplet ejections, preventing overload while still achieving sufficient white line closure through the elevated volume of each compensation droplet.
Solution Approach 2:
Instead of using high-frequency printing with standard droplet volumes, the patent employs partial action by using elevated compensation droplet volumes at lower frequencies. This approach achieves adequate coverage through larger individual droplets spaced at defined intervals, preventing nozzle overload while maintaining white line closure effectiveness.
Data Source
AI summary
A method for compensation for a failed print nozzle of an inkjet printhead for the printing of a printed image onto a print material conveyed in a transport direction, includes printing the printed image with at least two different print droplet volumes, one of which is a maximum print droplet volume. At least one compensation nozzle, i.e. a neighboring nozzle of the failed nozzle, prints compensation droplets with an elevated compensation droplet volume compared to the maximum print droplet volume. A frequency for the creation of compensation droplets is defined, and the compensation nozzle is actuated such that the defined frequency is observed and the successive compensation droplets printed by the compensation nozzle have a defined minimum separation in the transport direction.