Greyscale Printhead Waveform Optimization
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Solution Overview
Problem
Current greyscale printing technologies face limitations in achieving high printing rates and accurate dot placement due to the need for complex control mechanisms and sensitivity to printhead manufacturing inconsistencies, which affect ink drop velocity and size consistency.
Innovation Solution
A method and system for optimizing waveforms in greyscale printing that include a pulse train with optimized pulse length and inter-pulse time to control ink drop velocity, split drops, and drop placement error, using a cost function that balances these parameters with printing speed, resulting in stable and high-speed printing with consistent drop velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional waveforms are used to drive the printhead, then printing can be performed, but ink drop velocity consistency deteriorates and dot placement accuracy worsens
Solution Approach 1:
The patent applies parameter changes by optimizing waveform parameters (amplitude, pulse width, frequency) to compensate for manufacturing variations in printhead channels. The cost function systematically adjusts these parameters to achieve consistent ink drop velocities across channels with different geometries, thereby improving manufacturing precision while maintaining dot placement accuracy
Solution Approach 2:
The patent implements feedback through an iterative optimization process where the cost function evaluates ink drop velocity consistency and dot placement accuracy, then adjusts waveform parameters accordingly. This feedback loop continues until optimal parameters are found, ensuring both velocity consistency and placement accuracy are achieved simultaneously
2Productivity
If printing speed is increased, then productivity improves, but dot placement accuracy deteriorates due to velocity variations
Solution Approach 1:
The patent applies dynamics by making the waveform parameters adaptive rather than fixed. The optimization process determines dynamic parameter sets that adjust to different printing conditions and speeds, allowing the system to maintain velocity consistency and placement accuracy across a range of printing speeds, thus resolving the contradiction between productivity and precision
3Productivity
If complex control mechanisms are used to achieve high printing rates, then productivity improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-optimizing waveform parameters using the cost function before actual printing occurs. This offline optimization phase establishes the control parameters in advance, eliminating the need for complex real-time control mechanisms during printing, thus achieving high printing rates without increasing device complexity
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
The optimized waveform approach enables high-speed greyscale printing with consistent ink drop velocities and improved dot placement accuracy, reducing misplacement errors and energy inefficiencies associated with prior methods.
Implementation Method 1
PZT is a piezoelectric material, which is a material that deforms when an electric field is applied to it
Data Source
AI summary
A method provides an optimized set of waveforms for driving a printhead in greyscale printing wherein the waveforms include a pulse train of N pulses, wherein N is an integer, each pulse having a length LN, a time P(N-1)(N) existing between two adjacent pulses. The method includes: optimising a cost function that compares at least one ink ejection parameter such as drop velocity, difference in drop velocity, driving voltage, split velocity, number of split drops or drop placement error, with a printing speed parameter such as printing speed, the length LN of each pulse or the time P(N-1)(N) between two adjacent pulses.