Offset Drop Ejector Array for Printhead Redundancy
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Solution Overview
Problem
Current inkjet printheads face challenges in achieving high resolution and reliability while maintaining high speed, especially when drop ejectors fail during single-pass printing, leading to issues like white streaks and reduced throughput.
Innovation Solution
A two-dimensional array of drop ejectors is configured with spatially offset groups, allowing simultaneous and sequential firing to ensure each line is printed by multiple ejectors, providing redundancy and higher resolution through interlaced and redundant drop ejector modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single row of drop ejectors is used in conventional printheads, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate due to inability to compensate for failed ejectors and limited resolution
Solution Approach 1:
The patent transitions from a conventional single-row linear array of drop ejectors to a two-dimensional array configuration. This dimensional change allows multiple rows of ejectors to be arranged in a grid pattern, enabling redundant printing paths and higher resolution through multiple overlapping inkjet streams, thereby resolving the contradiction between improved precision and increased complexity.
Solution Approach 2:
The two-dimensional array is divided into multiple independent rows of drop ejectors, each row capable of independently contributing to the printed image. This segmentation allows the system to tolerate failures in individual rows or ejectors while maintaining overall print quality through compensation by adjacent rows, thus improving reliability without requiring a complete redesign of the entire printhead.
2Reliability
If multiple printheads are used to achieve high resolution and redundancy, then the reliability and resolution improve, but the device complexity and cost increase significantly
Solution Approach 1:
The patent merges multiple rows of drop ejectors into a single integrated two-dimensional array structure within one printhead assembly. This consolidation achieves the reliability and redundancy benefits of having multiple printheads while reducing the overall system complexity by eliminating the need for multiple separate printhead units, their individual mounting mechanisms, and associated alignment systems.
3Manufacturing precision
If drop ejectors are spaced closely to achieve high resolution, then the manufacturing precision improves, but the reliability worsens due to increased susceptibility to failures and reduced redundancy
Solution Approach 1:
By arranging drop ejectors in a two-dimensional grid rather than a single dense row, the system achieves high effective resolution through the combined output of multiple ejectors while maintaining greater spacing between individual ejectors in each row. This dimensional arrangement provides redundancy because adjacent rows can compensate for failures, thus resolving the contradiction between close spacing for resolution and spacing for reliability.
Data Source
AI summary
A method of printing an image with a printhead having spatially offset groups of drop ejectors, each group having a plurality of drop ejectors that are aligned substantially along a scan direction, includes enabling simultaneous firing of drop ejectors that are corresponding members of a first set of groups. Drop ejectors within each group of the first set are sequentially fired until each member of each group has had opportunity to fire. Corresponding drop ejectors of a second set of groups are simultaneously fired, and drop ejectors within each group of the second set are sequentially fired. Any additional groups of drop ejectors are likewise fired until all drop ejectors have had opportunity to fire during a first stroke. Drop ejectors are fired in subsequent strokes similar to the first stroke as the recording medium is moved relative to the printhead along the scan direction until printing is completed.