Liquid Discharge Head Pulse Timing to Reduce Satellite Droplets
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Solution Overview
Problem
Existing liquid discharge apparatuses face challenges in efficiently controlling the discharge of liquid droplets of varying sizes due to limitations in drive waveform design, leading to inconsistent droplet formation and satellite droplet formation.
Innovation Solution
A liquid discharge apparatus with a drive waveform comprising multiple pulses, including a final pulse with specific waveform elements, is employed to control the discharge of droplets. The waveform includes a first expansion, contraction, second expansion, second contraction, and third expansion phase, with timing between contraction phases optimized to match the natural vibration period of the liquid chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple single-pulse drive waveform is used, then the device complexity is reduced, but the droplet formation consistency deteriorates
Solution Approach 1:
The drive waveform is segmented into multiple pulses with distinct functions: a first pulse for initial droplet ejection and a second pulse for refining droplet formation. This segmentation allows each pulse to be optimized for its specific purpose, improving droplet consistency without requiring an overly complex single-pulse waveform
Solution Approach 2:
The drive waveform employs periodic pulsing with specific time intervals between the first and second pulses. The periodic action is synchronized with the natural vibration period of the liquid chamber (Tc), where the second pulse is timed to occur during a specific phase of the vibration cycle, thereby enhancing droplet formation control through rhythmic stimulation
2Manufacturing precision
If multi-pulse drive waveform is used, then the droplet formation consistency is improved, but the device complexity increases
Solution Approach 1:
The complex multi-pulse waveform is divided into functionally distinct segments: initial expansion phase, contraction phase, and a final pulse with specific timing. This segmentation makes the complex waveform more manageable and easier to implement by assigning specific functions to each pulse segment
Solution Approach 2:
The drive waveform dynamically adapts to the natural vibration characteristics of the liquid chamber. The timing and amplitude of subsequent pulses are adjusted based on the vibration state of the liquid, allowing the system to maintain optimal performance across varying operating conditions without requiring excessive complexity
3Ease of operation
If the timing between contraction phases is not optimized, then the control simplicity is maintained, but the satellite droplet formation increases
Solution Approach 1:
The drive waveform utilizes periodic pulsing synchronized with the natural vibration period of the liquid chamber. The time period from the start of the first contraction waveform element to the start of the second contraction waveform element is set within 0.5Tc to 0.6Tc, creating rhythmic stimulation that prevents satellite droplet formation while maintaining simple control logic
Solution Approach 2:
The waveform parameters are optimized by adjusting the timing intervals between contraction phases to match the natural vibration characteristics of the liquid chamber. This parameter optimization eliminates satellite droplets without complicating the control system, as it simply requires setting specific time relationships between pulses
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 enhances droplet formation consistency and reduces satellite droplet formation, improving the quality and reliability of liquid discharge.
Implementation Method 1
a plurality of pressure generators to generate a pressure that pressurizes liquid in the plurality of individual liquid chambers
Implementation Method 2
When a natural vibration period of the plurality of the plurality of individual liquid chambers is defined as Tc
Data Source
AI summary
A liquid discharge apparatus includes a liquid discharge head and a head drive controller to output a drive waveform including one pulse or two or more pulses selected according to a droplet size. In a case that the drive waveform includes the two or more pulses, the drive waveform includes a final pulse at an end of the two or more pulses. The final pulse includes a first expansion waveform, a first contraction waveform element, a second expansion waveform element, a second contraction waveform element, and a third expansion waveform element. A time period from a start of the first contraction waveform element to a start of the second expansion waveform element is less than 0.5 Tc. A time period from the start of the first contraction waveform element to a start of the second contraction waveform element is within a range from 0.5 Tc to 0.6 Tc.