Ink Droplet Ejecting Apparatus Stabilizing Pulse Width Optimization
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Solution Overview
Problem
Inkjet printers produce fine ink droplets known as mist, which do not land on the recording medium and instead adhere to internal printer parts, causing contamination and image quality degradation, due to the application of non-ejection pulses with high energy that stabilize ink droplet ejection but result in smaller droplets.
Innovation Solution
An ink-droplet ejecting apparatus with a drive signal waveform featuring a main pulse for ejecting ink droplets and a stabilizing pulse with a pulse width smaller than the rising time of the stabilizing pulse, ensuring the voltage application is terminated before reaching the predetermined drive voltage, thereby applying relatively low energy to prevent mist formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-ejection pulse (stabilizing pulse) with high energy is applied after the main pulse to stabilize ink droplet ejection, then the ejection stability is improved, but fine ink droplets (mist) are produced that do not land on the recording medium
Solution Approach 1:
The patent applies parameter changes by adjusting the pulse width of the stabilizing pulse to be smaller than the rising time, which changes the energy characteristics of the pulse. This modification reduces the energy applied during the stabilizing phase, preventing the formation of fine ink droplets (mist) while still maintaining ejection stability. The parameter adjustment directly addresses the contradiction by modifying the pulse characteristics rather than eliminating the stabilizing function.
Solution Approach 2:
The patent implements partial action by applying a stabilizing pulse with reduced energy (pulse width smaller than rising time) rather than full energy. This partial application of the stabilizing pulse is sufficient to dampen pressure wave pulsation and stabilize ejection, but insufficient to generate the harmful fine droplets. The principle resolves the contradiction by finding the minimum necessary energy level to achieve stability without excess that causes mist.
2Reliability
If the pulse width of the stabilizing pulse is increased to improve ejection stability, then the stability is improved, but the energy applied increases causing more mist formation
Solution Approach 1:
The patent changes the critical parameter of pulse width by setting it smaller than the rising time of the actuator response. This parameter change fundamentally alters the energy input characteristics, ensuring that the stabilizing pulse does not exceed the threshold that generates mist while maintaining sufficient energy to dampen pressure waves and stabilize ejection.
3Stability of the object's composition
If the stabilizing pulse is applied with sufficient energy to dampen pressure wave pulsation, then the pulsation is reduced, but the ink droplet size decreases forming mist
Solution Approach 1:
The patent applies partial action by using a stabilizing pulse with pulse width smaller than the rising time, which provides just enough energy to dampen pressure wave pulsation and stabilize the ink composition without exceeding the threshold that would fragment the droplet into mist. This partial application resolves the contradiction between achieving sufficient damping and maintaining proper droplet size.
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
Prevents the occurrence of ink mist while maintaining stable ink droplet ejection, reducing printer contamination and improving image quality by optimizing the pulse width and interval of the stabilizing pulse within specific ranges.
Implementation Method 1
an actuator which may be of piezoelectric type. The actuator is applied with a drive signal in the form of pulses to be displaced or deformed thereby, in order to apply a pressure to ink in the pressure chamber to eject a droplet of the ink from the nozzle
Implementation Method 2
a waveform of the drive signal is changed depending on whether it is instructed to eject an ink droplet immediately before or after a specific ink droplet or dot... a pulse width of the main pulse is 1.0AL and the stabilizing pulse having a pulse width of 0.2AL-0.3AL is applied after an interval of 0.4AL-0.6AL from the main pulse
Data Source
AI summary
There is disclosed an ink-droplet ejecting apparatus including a pressure chamber filled with an ink, an actuator which varies an inner volume of the pressure chamber, and a control unit which has a drive-signal generator. The drive-signal generator generates a drive signal and applies the drive signal to the actuator when a droplet of the ink is to be ejected onto a recording medium The drive signal is generated to be in one of at least one waveform including a waveform including a main pulse Pm in order to eject the ink droplet, and a stabilizing pulse Ps applied after the main pulse Pm in order not to eject an ink droplet. A pulse width Ts of the stabilizing pulse Ps is smaller than a rising time of the stabilizing pulse Ps.