Inkjet Droplet Pulse Timing for Stable High-Frequency Discharge
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Solution Overview
Problem
Conventional liquid droplet discharging apparatuses face instability in discharge at high frequencies and inability to adjust droplet amounts, preventing high-speed recording and gradation expression.
Innovation Solution
A liquid droplet discharging apparatus with a pull-strike system using a driving signal comprising a main pulse and a cancel pulse, where the time from the end of the main pulse to the start of the cancel pulse (Tw) and the width of the cancel pulse (Tc) are controlled to satisfy specific expressions, enabling stable discharge and gradation expression at high frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the driving frequency is raised higher than conventional levels, then the recording speed is improved, but the discharge stability deteriorates
Solution Approach 1:
The driving signal is segmented into multiple pulse components (first pulse, second pulse, third pulse) within one discharging cycle. The first pulse generates the main pressure wave for droplet ejection, the second pulse suppresses satellite droplets, and the third pulse cancels residual pressure waves. This segmentation allows the system to operate at higher frequencies while maintaining discharge stability through coordinated pulse timing and amplitude control.
Solution Approach 2:
The invention implements periodic action by applying multiple pulses within each discharging cycle at optimized time intervals. The periodic structure of multiple pulses per cycle enables the system to maintain stable droplet discharge at high driving frequencies by continuously resetting and controlling the pressure wave dynamics in the ink channel.
2Productivity
If the driving frequency is raised higher, then the recording speed is improved, but the gradation expression capability deteriorates
Solution Approach 1:
The invention applies dynamics by making the pulse signal parameters (amplitude, duration, timing) adjustable and adaptive. The controller can dynamically adjust the parameters of the first, second, and third pulses to control the amount of liquid droplet discharged. This dynamic control enables gradation expression at high frequencies by varying pulse characteristics rather than relying on fixed signal configurations.
Solution Approach 2:
The invention utilizes parameter changes by modifying the amplitude, duration, and timing parameters of the pulse signals to control droplet discharge量. By changing these parameters, the system can achieve different droplet sizes and discharge amounts, enabling gradation expression while maintaining high recording speed through optimized parameter selection.
3Device complexity
If a fixed pulse signal configuration is used, then the device complexity is reduced, but the adaptability for different discharge amounts deteriorates
Solution Approach 1:
The invention transitions from fixed to dynamic pulse signal configuration, where the controller can adjust the parameters (amplitude, duration, timing) of multiple pulses within each discharging cycle. This dynamic capability allows the system to adapt to different discharge amount requirements while maintaining manageable complexity through automated control.
Solution Approach 2:
The system enables discharge amount adjustment by changing pulse signal parameters such as amplitude and duration. The controller can modify these parameters to achieve different droplet discharge amounts, providing adaptability without requiring complex mechanical adjustments or multiple fixed signal configurations.
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 apparatus achieves stable discharge and gradation expression at high frequencies, supporting high-resolution imaging up to 1200 dpi and preventing unintended droplet discharge, with metal nozzles providing durability and resistance to abrasion.
Implementation Method 1
an actuator configured to apply pressure to liquid inside the pressure chamber
Implementation Method 2
a pressure wave is generated in an ink channel and ink droplets are discharged from a nozzle
Data Source
AI summary
A liquid droplet discharging apparatus includes: a channel member having a nozzle and a pressure chamber; an actuator which applies pressure to liquid inside the pressure chamber; and a controller which applies a driving signal to the actuator. Within one discharging cycle, the driving signal includes: a main pulse for causing a liquid droplet to be discharged from the nozzle; and a cancel pulse which is applied to the actuator after the main pulse. In a case that a driving frequency of the driving signal is f (unit: kHz), a time from an end point of the main pulse to a start point of the cancel pulse is Tw (unit: μsec) and a width of the cancel pulse is Tc (unit: μsec), the following expressions (1) and (2) hold: 50≤f≤−11.3×(Tw+Tc)+120 . . . (1); and Tw+Tc≤5.2 . . . (2).