Piezoelectric Inkjet Head Drive Timing Control
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Solution Overview
Problem
Liquid ejection apparatuses face variations in flight velocity of liquid among nozzle rows due to manufacturing variations, leading to inconsistent landing positions, which degrade image quality and require reduced ejection speed to maintain accuracy, increasing noise and complexity in signal wiring.
Innovation Solution
A liquid ejection apparatus with a control system that outputs customized drive signals and selection control signals for each nozzle group, allowing for adjusted ejection timing based on individual flight velocities, reducing landing position variations and enabling higher ejection frequencies without increasing signal lines or wiring complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common drive waveform is used for all nozzle rows, then the device complexity is reduced, but the manufacturing precision of liquid ejection deteriorates due to flight velocity variations among nozzle rows
Solution Approach 1:
The patent segments the drive waveform control by creating multiple drive waveform groups (first through fourth groups) with different timing offsets, and assigns specific groups to specific nozzle rows based on their flight velocity characteristics. This segmentation allows customized timing control for each nozzle row while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent applies local quality by setting different timing offsets for different drive waveform groups according to the specific flight velocity characteristics of different nozzle rows. Each nozzle row receives a drive waveform with timing optimized for its local characteristics, improving landing position precision without requiring completely independent control for each nozzle.
2Manufacturing precision
If the ejection operation speed is suppressed below a certain speed, then the landing position precision is maintained, but the productivity of the liquid ejection apparatus deteriorates
Solution Approach 1:
The patent implements dynamics by making the drive waveform timing adjustable and adaptable. Instead of using a fixed common timing for all nozzles, the system dynamically selects appropriate timing offsets from multiple drive waveform groups based on flight velocity measurements, allowing the system to maintain precision while operating at higher speeds.
Solution Approach 2:
The patent changes the timing parameter of drive waveforms by creating multiple groups with different timing offsets. By measuring flight velocities and selecting the appropriate timing offset from the available groups, the system optimizes ejection timing for each nozzle row, enabling higher ejection speeds while maintaining landing position precision.
3Manufacturing precision
If drive waveforms with different timing are applied to each nozzle row, then the landing position precision is improved, but the device complexity increases due to increased signal lines and wiring
Solution Approach 1:
The patent applies universality by creating a set of drive waveform groups that can serve multiple nozzle rows. Instead of creating completely independent drive waveforms for each nozzle, the system uses a universal set of timed groups that can be selectively applied to different nozzle rows, reducing wiring complexity while maintaining precision.
Solution Approach 2:
The patent uses partial action by implementing timing differentiation only where necessary - specifically for nozzle rows with significantly different flight velocities. Nozzle rows with similar characteristics can share the same drive waveform group, reducing the overall complexity while still providing timing adjustment where it most impacts precision.
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 adjusts ejection timing for each nozzle group to minimize landing position variations, allowing for higher ejection frequencies while maintaining accuracy and reducing the complexity of signal wiring and circuit size.
Implementation Method 1
a pressure generation means, such as a piezoelectric element, which is driven by a drive waveform applied thereto
Data Source
AI summary
A printer controller outputs plural drive signals including respective series of drive pulses, the timing points of which are different from one another, to a head control unit side, and outputs a multiplexed signal resulting from multiplexing change signals corresponding to the respective drive signals to a head control unit side, and the head control unit includes a control signal demultiplexing unit which demultiplexes the multiplexed signal into the change signals corresponding to respective nozzle rows, and an actuator control unit which, on the basis of each of the demultiplexed change signals, selects one of the drive pulses included in one of the drive signal which corresponds to the demultiplexed change signal, and applies the selected drive pulse to a piezoelectric element included in one of the nozzle rows which corresponds to the drive signal corresponding to the demultiplexed change signal.