Liquid Ejecting Device Ink Refilling Pressure Loss
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Solution Overview
Problem
Ink refilling systems for high-flow rate applications face pressure loss due to fluid resistance in long tubes, leading to insufficient refilling and instability in ink ejection, particularly in large-format printing, where existing solutions either fail to ensure efficient air bubble discharge or adequate ink refilling.
Innovation Solution
A liquid ejecting device with a head tank, pressure adjusting tank, and dual liquid sending devices that maintain negative pressure in the head tank, allowing on-demand ink feeding and efficient air bubble discharge through a system with controlled flow resistance and air discharging ports, ensuring stable and high-speed ink delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the length of tube is increased to feed ink to head tank, then the coverage area is improved, but the pressure loss due to fluid resistance increases causing insufficient refilling
Solution Approach 1:
The ink feeding system is segmented into two independent pathways: a first liquid sending device for ink supply and a second liquid sending device for air bubble discharge. This segmentation allows each pathway to be optimized independently, with the discharge pathway having lower fluid resistance to maintain pressure differential.
Solution Approach 2:
The system preliminarily establishes a pressure differential by providing a discharge pathway with lower fluid resistance than the supply pathway. This pre-established pressure difference prevents backflow and ensures unidirectional ink flow, counteracting the pressure loss in long supply tubes.
2Productivity
If the flow rate of ink is increased to improve printing throughput, then the productivity is improved, but the pressure loss increases causing insufficient refilling
Solution Approach 1:
The system separates ink supply and air bubble discharge into different pathways with different flow rate requirements. The discharge pathway is designed with lower fluid resistance to handle high flow rates of air bubbles without significant pressure loss, while the supply pathway can operate at lower flow rates.
Solution Approach 2:
The system utilizes pneumatic principles by introducing air bubbles into the ink stream. The air bubbles rise through the ink due to buoyancy, and the second liquid sending device facilitates this气液 separation process, allowing high-speed ink ejection without proportional increases in supply pressure.
3Productivity
If the length of head is increased to increase number of nozzle heads, then the productivity is improved, but the efficiency of air bubble discharge is deteriorated
Solution Approach 1:
The discharge pathway is segmented as a separate system with dedicated low-resistance channels. This allows air bubbles from multiple nozzle heads to be efficiently collected and discharged through a common pathway designed specifically for gas-liquid separation, maintaining high discharge efficiency regardless of head length.
Solution Approach 2:
The system adds a vertical dimension to air bubble discharge by utilizing buoyancy forces. Air bubbles naturally rise upward in the ink stream, and the second liquid sending device is positioned to facilitate this upward movement, creating a three-dimensional flow pattern that efficiently separates gases from liquids across the entire head length.
4Adaptability or versatility
If tube length is increased for large-sized printing medium, then the adaptability is improved, but the ejection stability is deteriorated due to pressure loss
Solution Approach 1:
The system preliminarily establishes a pressure differential between supply and discharge pathways to prevent backflow and maintain unidirectional ink flow. This pre-established pressure gradient compensates for pressure losses in long tubes, ensuring stable ink delivery to the nozzle regardless of tube length.
Solution Approach 2:
The system provides feedback control by monitoring the pressure differential between the ink supply and discharge pathways. The second liquid sending device adjusts its operation based on the accumulated air bubbles and pressure conditions, maintaining optimal flow conditions for stable ejection even over long tube lengths.
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 prevents insufficient refilling and ensures stable, high-speed ink delivery even with increased flow rates and long tubes, improving ejection stability and reliability by maintaining appropriate negative pressure and facilitating air bubble discharge.
Implementation Method 1
a first liquid sending device configured to send liquid from the liquid storing container to the head tank
Implementation Method 2
maintain negative pressure in the head tank, allowing on-demand ink feeding and efficient air bubble discharge
Implementation Method 3
a vibration plate is provided on a part of the wall of a liquid chamber filled with ink and the vibrating plate is displaced by a piezoelectric actuator or the like so as to change the volume of the liquid chamber and increase the pressure therein
Data Source
AI summary
Disclosed is a liquid ejecting device including a liquid ejecting head including a liquid ejecting nozzle, a head tank configured to store liquid to be fed to the liquid ejecting head, a liquid storing container configured to store liquid to be fed to the head tank, a first liquid sending device configured to send liquid from the liquid storing container to the head tank, a pressure adjusting tank configured to store liquid suctioned from the liquid ejecting head, and a second liquid sending device configured to send liquid from the liquid ejecting head to the pressure adjusting tank, wherein the head tank includes a liquid receiving port configured to receive liquid from the liquid storing container via a liquid receiving valve being opened at a predetermined or less pressure and a liquid feeding port configured to feed liquid to the liquid ejecting head and the liquid ejecting head includes a liquid inflow port communicating with the liquid feeding port and a liquid outflow port communicating with the pressure adjusting tank via the second liquid sending device.