Liquid Jet Head Drive Waveform Control for Fine Ejection Volume Adjustment
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Solution Overview
Problem
Existing liquid jet recording devices face challenges in finely adjusting ejection volume without degrading ejection speed, particularly when attempting to achieve intermediate grayscale values between 1 and 2 drops, due to the inherent fixed ejection volume in head structure and significant impact of drive waveform parameter changes on ejection speed.
Innovation Solution
The liquid jet head employs a control circuit that varies the crest value of positive pulse signals applied to the actuator plate, allowing for adjustable ejection volume between 'drops' without altering the head structure or pulse width, by expanding and contracting the capacity of liquid ejection channels, enabling fractional adjustments in ejection volume while maintaining constant ejection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the parameter of the drive waveform is changed to adjust ejection volume, then the ejection volume can be adjusted, but the ejection speed is significantly affected and image quality degrades
Solution Approach 1:
The patent changes the physical state of the liquid in the ejection channel by controlling its phase (liquid vs. vapor) rather than changing drive waveform parameters. By heating the liquid to create vapor bubbles that expand and contract, the system adjusts ejection volume while maintaining consistent drive conditions and ejection speed.
2Quantity of substance
If the head structure is modified to change ejection volume, then the ejection volume can be adjusted, but the head structure becomes less flexible and requires physical changes
Solution Approach 1:
The patent replaces the mechanical approach of physically changing head structure with a thermal field approach. Instead of modifying the physical geometry of ejection channels, the system uses temperature control to change the liquid's phase and volume, achieving adjustable ejection without structural modifications.
3Adaptability or versatility
If multiple grayscale values are implemented by ejecting multiple drops, then the ejection volume range is increased, but the ejection speed and image quality are compromised
Solution Approach 1:
The patent achieves multiple grayscale values by controlling the phase state and volume of a single liquid ejection rather than ejecting multiple separate drops. By adjusting temperature to control vapor bubble formation and expansion, the system varies the effective ejection volume continuously while maintaining single-drop ejection timing and speed, thus preserving image quality.
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 approach allows for precise adjustment of ejection volume without compromising ejection speed, enabling high-definition image quality and efficient droplet ejection across a range of grayscale values.
Implementation Method 1
a plurality of liquid ejection channels 45A corresponding respectively to the plurality of nozzle holes 43a and filled with the liquid, the capacities of the liquid ejection channels 45A being variable, and a control circuit 35 for applying pulse signals to the actuator plate 40 to expand and contract the capacities of the liquid ejection channels 45A
Data Source
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AI summary
An ejection volume of a liquid can more finely be adjusted without lowering the ejection speed. The liquid jet head includes a plurality of nozzles adapted to jet the liquid, a piezoelectric actuator having a plurality of pressure chambers corresponding respectively to the nozzles and filled with the liquid, and adapted to vary a capacity of each of the pressure chambers, and a control section adapted to apply a pulse signal to the piezoelectric actuator to thereby expand and contract the capacity of the pressure chamber so as to jet the liquid with which the pressure chamber is filled. The control section generates a drive waveform including a plurality of the pulse signals adapted to expand the capacity of the pressure chamber, and sets a crest value of either of the pulse signals other than the pulse signal applied last to a different value from a crest value of another of the pulse signals in the drive waveform.