Multi-Pulse Waveform Droplet Ejection Velocity Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Droplet ejection devices face variations in droplet velocity and size due to moving targets or ejectors, leading to image quality degradation and performance issues in imaging and other applications.

Innovation Solution

The use of multi-pulse waveforms with embedded pulses allows for the generation of droplets of different sizes at substantially the same effective drop velocity by adjusting the positions and presence of drive pulses within the waveform, ensuring consistent droplet ejection across various sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multi-pulse waveforms are used to eject droplets of different sizes, then droplet volume variability is improved, but droplet velocity consistency deteriorates

Engineering Contradiction:
Improvedroplet volumeVSAvoiddroplet velocity
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The waveform is segmented into multiple discrete pulses, where each pulse corresponds to a specific droplet size. By selectively activating different portions of the multi-pulse waveform (single pulse, dual pulse, triple pulse configurations), the system can eject droplets of varying volumes while maintaining consistent velocity through carefully timed pulse sequences.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes waveform parameters (pulse width, pulse amplitude, pulse timing) to achieve different droplet sizes while maintaining constant droplet velocity. Specifically, the embedded waveform technique adjusts the timing and duration of individual pulses within the multi-pulse sequence to compensate for size variations and maintain velocity consistency.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If variable droplet sizes are ejected, then image resolution and detail are improved, but position accuracy deteriorates due to velocity variations

Engineering Contradiction:
Improveimage qualityVSAvoiddroplet position
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The embedded waveform technique performs preliminary velocity compensation by pre-calculating and embedding specific pulse timing adjustments into the waveform sequence. Before droplet ejection, the system prepares the waveform with embedded timing corrections that ensure droplets of different sizes will arrive at the target position simultaneously, preventing position accuracy degradation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from droplet size detection to adjust waveform parameters in real-time. By monitoring the actual droplet size produced and comparing it to the target size, the system dynamically adjusts subsequent waveform parameters to maintain both size consistency and velocity uniformity, thereby preserving position accuracy.

Inventive Principle:
Principle #23Feedback

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 maintains consistent effective drop velocity for droplets of varying sizes, improving image quality and system performance by minimizing variations in droplet position and size, thereby enhancing the precision and reliability of droplet ejection.

Implementation Method 1

The ink jet module includes a piezoelectric element positioned over the pumping chamber

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

generating a multi-pulse waveform that includes drive pulses in predetermined positions in the waveform... applying the multi-pulse waveform to the actuator... causing the droplet ejection device to eject droplets

Methodology Applied
Scientific EffectPressure wave propagation:

Data Source

PatentEP2296895B1Process and apparatus to provide variable drop size ejection with an embedded waveform
Publication Date: 2014.01.22 FUJIFILM DIMATIX INC
  • EP2296895B1 patent drawingFigure 1
  • EP2296895B1 patent drawingFigure 2
  • EP2296895B1 patent drawingFigure 3

AI summary

Described herein is a process and apparatus for driving a droplet ejection device with embedded multi-pulse waveforms. In one embodiment, the process includes generating a multi-pulse waveform that includes drive pulses in predetermined positions. Next, the process includes applying the drive pulses to the actuator and causing the droplet ejection device to eject a first droplet of a fluid. The process also includes applying a second multi-pulse waveform having at least one embedded pulse to the actuator and causing the droplet ejection device to eject a second droplet of the fluid. Each embedded pulse is embedded between predetermined positions of two drive pulses. In some embodiments, the first and second droplets have different droplet sizes and these droplets are ejected at substantially the same effective drop velocity.