Liquid Ejection Pulse Damping for Stable High-Speed Droplet Placement
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in stabilizing ink ejection at high speeds due to insufficient time for damping nozzle vibrations, leading to unstable ink droplet placement on the medium.
Innovation Solution
A drive signal generator generates a drive signal with specific ejection pulses that include filling, ejection, and damping elements, ensuring a sufficient time period for pressure chamber damping, allowing for stable ink droplet formation and placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the time interval between ejection pulses is reduced to achieve high-speed driving, then productivity is improved, but the stability of ink ejection deteriorates due to insufficient damping time for nozzle vibrations
Solution Approach 1:
The damping element performs preliminary damping action by generating negative pressure before the main ejection pulse. This preliminary negative pressure reduces the residual vibration of the ink column in advance, creating favorable conditions for stable subsequent ejection even at reduced time intervals between pulses
Solution Approach 2:
The invention changes the pressure parameter profile by introducing a damping element that generates negative pressure (lower than reference pressure) before the ejection pulse. This parameter change allows the system to achieve both high ejection speed and stable ejection by properly controlling the pressure timing and magnitude
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 stabilizes ink droplet ejection, enabling precise and stable dot formation on the medium even at high speeds by effectively managing nozzle vibrations.
Implementation Method 1
a drive element such as a piezoelectric element that causes pressure applied to the liquid in the pressure chamber to fluctuate in accordance with a drive signal
Implementation Method 2
The last ejection pulse includes a damping element that reduces a fluctuation in the pressure in the pressure chamber by changing in electrical potential after the ejection element of the last ejection pulse
Data Source
AI summary
In a liquid ejecting apparatus, a drive signal includes a plurality of ejection pulses corresponding to a plurality of droplets that are combined before landing on a medium. The plurality of ejection pulses has filling elements and ejection elements. The ejection element of a first ejection pulse changes in electrical potential from a first electrical potential to a reference electrical potential. The ejection element of the last ejection pulse changes in electrical potential from a second electrical potential to a third electrical potential. The reference electrical potential is between the first electrical potential and the third electrical potential and between the second electrical potential and the third electrical potential. A time period from the start of the filling element of the last ejection pulse to the start of the ejection element of the last ejection pulse is greater than or equal to 0.3 TC and less than 0.5 TC.