High-Speed Printhead Nozzle Row Firing Control
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Solution Overview
Problem
Existing high-speed monochrome printheads using Memjet technology face limitations in achieving seamless printing across nozzle rows due to fixed firing frequencies and dot pitch variations, resulting in print artefacts at different resolutions and speeds, particularly at 5× speed with 400 dpi and 1200 dpi.
Innovation Solution
The solution involves independently firing nozzle rows in the dropped nozzle region relative to the main nozzle region, with a configurable delay and buffer system to align droplets perfectly across the join region, and sub-row firing schemes to reduce artefacts, allowing for a wider range of print modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed offset of the dropped nozzle region is used to compensate for join region errors, then seamless printing is achieved at specific resolutions (1600 dpi, 800 dpi), but print artefacts occur at other resolutions (1200 dpi, 400 dpi) and speeds
Solution Approach 1:
The patent implements dynamic adjustment of the dropped nozzle region offset based on detected print artefacts. The system monitors for join region errors at different resolutions and speeds, then dynamically modifies the offset compensation values to eliminate artefacts. This transforms the static fixed offset system into a dynamic adaptive system that maintains print quality across varying print modes.
Solution Approach 2:
The patent changes the offset parameter values for the dropped nozzle region based on the specific print resolution and speed being used. By adjusting these timing and position parameters dynamically, the system optimizes dot placement accuracy for each print mode, eliminating the artefacts that occur when using a single fixed offset value for all conditions.
2Productivity
If all nozzle rows are used for monochrome printing to increase print speed, then higher productivity is achieved, but fixed firing frequency limits the ability to print at different speeds and resolutions
Solution Approach 1:
The patent enables dynamic control of nozzle row firing sequences, allowing the system to selectively activate and time the firing of different nozzle rows based on the desired print speed and resolution. This dynamic firing control breaks the fixed frequency constraint and allows adaptation across multiple print modes while maintaining high productivity.
Solution Approach 2:
The patent implements periodic firing patterns for different nozzle rows with configurable time intervals. By controlling the periodicity and timing of droplet ejection from each nozzle row independently, the system can achieve variable print speeds and resolutions while utilizing all nozzle rows for high-speed monochrome printing.
3Measurement precision
If the dropped nozzle region is offset by a fixed number of print lines, then dot alignment is achieved at 1600 dpi, but alignment errors increase at lower resolutions like 400 dpi
Solution Approach 1:
The patent dynamically changes the offset parameter for the dropped nozzle region based on the target print resolution. At 1600 dpi, one offset value is used, while at 400 dpi, a different offset value is applied. This parameter adaptation ensures that dot placement accuracy is maintained across all resolutions by adjusting the compensation timing and position to match the specific resolution requirements.
Data Source
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AI summary
A method of printing an image from a printhead module having a plurality of horizontal nozzle rows. Each nozzle row has a main row portion and a corresponding dropped row portion vertically offset from the main row portion. The method includes the steps of: determining a predetermined delay for the dropped row portions based on the offset, a print speed and a print resolution; allocating dot data for image lines to respective nozzle rows based on the print speed and print resolution, sending first dot data for each main row portion and second dot data for each dropped row portion to the printhead module; and firing nozzles from the main row portions and dropped row portion in a predetermined sequence. Each dropped row portion is fired independently of its corresponding main row portion and delayed relative to its corresponding main row portion by the predetermined delay.