Inkjet Printhead Drop Ejector Array Redundancy
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Solution Overview
Problem
Current inkjet printing technologies face challenges in achieving high resolution and reliability, especially when performing high-speed single-pass printing, as they often result in image uniformity issues due to the failure of individual drop ejectors, which can lead to noticeable white streaks and reduced throughput.
Innovation Solution
A two-dimensional array of drop ejectors is arranged in a specific configuration with multiple columns, each containing banks and groups of drop ejectors that are aligned and offset, allowing for cooperative printing and redundancy to ensure image uniformity even if individual drop ejectors fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single row of drop ejectors is used for high-speed printing, then printing speed is improved, but reliability deteriorates due to white streaks from individual ejector failures
Solution Approach 1:
The printhead array is divided into multiple independent rows of drop ejectors, each capable of printing the same scan line. This segmentation allows the system to maintain high printing speed while improving reliability through redundancy, as failed ejectors in one row can be compensated by corresponding ejectors in other rows.
Solution Approach 2:
Different rows of drop ejectors are assigned to print different portions of the same scan line, with each row having specialized responsibility for specific dot positions. This local quality assignment ensures that the failure of individual ejectors does not result in visible white streaks, as adjacent rows can compensate for local failures.
2Reliability
If multiple printheads are used to provide printing redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
Multiple rows of drop ejectors are merged into a single integrated printhead array, sharing common ink supply channels and control circuitry. This merging approach provides printing redundancy and improved reliability while minimizing device complexity by avoiding the need for completely separate printhead assemblies.
Solution Approach 2:
Each row of drop ejectors is designed to be multi-functional, capable of printing the same scan line independently. This universality allows any row to compensate for failures in other rows, providing redundancy without requiring specialized components for each row.
3Manufacturing precision
If drop ejectors are closely spaced to achieve high resolution, then manufacturing precision is improved, but ease of manufacture deteriorates due to fabrication challenges
Solution Approach 1:
Instead of achieving high resolution by simply reducing the spacing between ejectors in a single row, the invention uses multiple rows spaced at larger intervals, with each row containing fewer ejectors. This dimensional approach to resolution (using row multiplication rather than ejector miniaturization) improves ease of manufacture while maintaining high effective resolution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables high-resolution printing with improved reliability and reduced manufacturing costs, as it allows for continuous printing without white streaks and maintains high yield and long print lifetime by distributing the printing task among multiple drop ejectors.
Implementation Method 1
an actuator configured to selectively pressurize the pressure chamber for ejecting ink through the nozzle
Implementation Method 2
A heater 35, which functions as the actuator, is formed on the surface of the base plate 10 within each pressure chamber 22 and is configured to selectively pressurize the pressure chamber 22 by rapid boiling of a portion of the ink
Implementation Method 3
a pressurization actuator (thermal or piezoelectric, for example)
Data Source
AI summary
An inkjet printhead includes a two-dimensional array of drop ejectors arranged as a plurality of columns, each column including a plurality of banks, and each bank including a plurality of groups that each include a plurality of drop ejectors. The drop ejectors in each group are substantially aligned along a first direction. The groups in each bank are spaced from each other along the first direction and are offset from each other along a second direction. The banks in each column are spaced from each other along the first direction and are offset from each other along the second direction. The columns are offset from each other along the second direction. The two-dimensional array has a width W along the first direction and a length L greater than W along the second direction. Each drop ejector includes a nozzle, an ink inlet, a pressure chamber and an actuator.