Inkjet Head Drive Waveforms for Satellite Mist Suppression
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Solution Overview
Problem
Existing liquid ejection heads, such as inkjet printers, generate satellite mist during ink droplet ejection, which deteriorates print quality by causing irregular landing.
Innovation Solution
A liquid ejection head with a drive signal that includes specific waveforms to control the pressure chamber transitions, adjusting the timing of contraction states to minimize satellite mist formation, including a first contracted state followed by a second contracted state at a delayed timing relative to the initial contraction, and optionally additional contraction waveforms to stabilize the pressure chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional drive waveform is used to eject ink droplets, then the liquid ejection function is achieved, but satellite mist is generated causing deterioration of print quality
Solution Approach 1:
The drive waveform is segmented into multiple distinct phases: expansion waveform, first contraction waveform, second contraction waveform, and third waveform. Each phase serves a specific function in controlling liquid ejection and minimizing satellite mist generation, thereby resolving the contradiction between achieving liquid ejection and preventing harmful satellite mist.
Solution Approach 2:
The drive waveform employs periodic expansion and contraction cycles with specific timing relationships. The expansion-contraction sequence is designed to occur at predetermined time intervals, creating controlled periodic pressure changes that enable precise liquid ejection while suppressing satellite mist formation through rhythmic pressure modulation.
2Speed
If the pressure chamber is contracted quickly to eject liquid, then ejection speed is improved, but satellite mist generation increases
Solution Approach 1:
The contraction process is divided into two distinct contraction waveforms with different characteristics. The first contraction waveform provides initial rapid contraction for fast ejection, while the second contraction waveform provides additional controlled contraction to suppress satellite mist, thus achieving both high ejection speed and reduced satellite generation.
Solution Approach 2:
The expansion waveform is applied before the contraction waveforms to preliminarily prepare the liquid for ejection. This preliminary expansion action ensures the liquid is ready for rapid ejection when contraction occurs, while the subsequent controlled contraction phases prevent excessive pressure that would generate satellite mist.
3Manufacturing precision
If multiple contraction waveforms are applied to reduce satellite mist, then print quality is improved, but drive signal complexity increases
Solution Approach 1:
Multiple contraction waveforms and expansion waveforms are merged into a single integrated drive signal that can be generated and applied simultaneously to all piezoelectric actuator elements. This unified approach reduces the complexity of signal generation and distribution while achieving the satellite mist reduction benefit of multiple contraction phases.
Solution Approach 2:
The multi-phase drive waveform serves multiple functions simultaneously: the expansion waveform prepares the liquid, the first contraction waveform enables rapid ejection, the second contraction waveform suppresses satellite mist, and the third waveform stabilizes the system. This multi-functionality is achieved through a single drive signal design, avoiding the need for separate control systems for each function.
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 solution effectively reduces satellite mist and improves landing accuracy, achieving better print quality by minimizing irregular droplet landing and satellite formation.
Implementation Method 1
The inkjet head ejects the ink droplets from nozzles communicating with pressure chambers by changing their volumes with piezoelectric actuator elements
Data Source
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AI summary
A liquid ejection head includes a nozzle, a pressure chamber that is capable of storing liquid and communicates with the nozzle, a volume of the chamber being variable to eject the liquid from the nozzle, an actuator configured to vary the volume in response to a drive signal, and a drive circuit configured to generate the signal. The chamber has one of states including a steady state in which the volume is unchanged, an expanded state in which the volume is expanded, a first contracted state in which the volume is contracted, and a second contracted state in which the volume is further contracted. The drive signal comprises a first waveform for transitioning from the steady state to the first contracted state, a second waveform for transitioning from the first to second contracted states, and a third waveform for transitioning from the second contracted state to the steady state.