Drive Circuit Waveform Control for Inkjet Actuator Current Balance
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Solution Overview
Problem
In liquid ejection devices, such as inkjet heads, there is a challenge in suppressing the inflow of current at an intermediate potential, which can occur due to an imbalance in the outflow and inflow of current during multi-drop driving.
Innovation Solution
A drive device for a liquid ejection device is designed with a drive circuit that outputs a specific drive waveform to the actuator. This waveform transitions from a first potential higher than the intermediate potential to a second potential lower than the intermediate potential, and then back to the intermediate potential, all within a time period less than or equal to the charge-discharge time constant of the actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a voltage is continuously supplied to an actuator during a pulse period equal to the acoustic length to continuously eject multiple ink droplets, then multi-drop driving is achieved, but current inflow at the intermediate potential occurs due to imbalance between outflow and inflow of current
Solution Approach 1:
The drive waveform is segmented into distinct voltage levels (first potential, intermediate potential, second potential) with specific transition sequences. By dividing the voltage application into staged segments rather than continuous application, the patent controls current flow at each stage to prevent imbalance and inflow at the intermediate potential while maintaining multi-drop ejection capability.
2Reliability
If the drive waveform transitions voltage levels to control current flow, then current inflow is suppressed, but the drive waveform complexity increases
Solution Approach 1:
The patent employs periodic voltage transitions following a specific sequence (first potential → second potential → intermediate potential) within each pulse period. This periodic action pattern, synchronized with the acoustic length, systematically suppresses current inflow at the intermediate potential while maintaining manageable waveform complexity through repetition of the established sequence.
Data Source
AI summary
According to one embodiment, a drive device for a liquid ejection device or the like includes a drive circuit configured to output a drive waveform to an actuator of a liquid ejection unit. The actuator has a charge-discharge time constant. The drive waveform during a non-initial portion makes a transition from a first potential higher than an intermediate potential to a second potential lower than the intermediate potential and then a transition from the second potential to the intermediate potential within a time period less than or equal to the charge-discharge time constant.