Liquid Supply Regulators for Ink End Detection
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Solution Overview
Problem
Existing liquid discharge apparatuses face challenges in accurately detecting ink end conditions due to negative pressure states causing erroneous ink supply path pressure fluctuations, leading to potential air mixture and incorrect ink end detection.
Innovation Solution
The apparatus includes a pressure detector and control circuitry that determine a low-level tank by monitoring the opening and closing conditions of liquid supply regulators, ensuring accurate ink supply from multiple tanks to the liquid discharge head, thereby preventing erroneous ink end detection and maintaining high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump is driven to supply ink from the tank when ink remaining amount is low, then the pump can continue operating, but the supply path turns to negative pressure state causing erroneous pressure detection and potential air mixture
Solution Approach 1:
The ink supply system is segmented into multiple independent tanks (first tank and second tank) with separate liquid supply regulators for each. This segmentation allows the system to switch between tanks and prevents the entire system from entering negative pressure state, as each tank can be independently managed and sealed when not in use.
Solution Approach 2:
The liquid supply regulators act as intermediaries between the tanks and the pump. They control the opening and closing of supply paths, ensuring that only the active tank connects to the pump while the other remains sealed. This intermediary control prevents air mixture and maintains accurate pressure detection in the supply path.
2Reliability
If multiple tanks are used to store liquid, then the system can avoid negative pressure by switching tanks, but the device complexity increases with multiple liquid supply regulators
Solution Approach 1:
Multiple liquid supply regulators are provided, with each regulator capable of controlling supply from its associated tank. The regulators perform dual functions: regulating liquid flow when open and sealing the supply path when closed. This multi-functionality allows simple binary control (open/closed) for each regulator, managing complexity through functional integration rather than adding separate mechanisms.
3Measurement precision
If the pressure detector is disposed between the liquid supply regulators and the liquid discharge head, then accurate pressure monitoring is achieved, but the system becomes more sensitive to pressure fluctuations from tank switching operations
Solution Approach 1:
The liquid supply regulator corresponding to the tank to be switched is closed in advance before switching operations. This preliminary closing action seals the supply path and prevents pressure fluctuations from propagating to the pressure detector during tank switching, ensuring stable and accurate pressure monitoring.
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 configuration effectively suppresses air mixture in the ink supply path, allowing for precise detection of ink end conditions and preventing incorrect ink end detection, ensuring reliable operation and maintaining high accuracy in ink management.
Implementation Method 1
When the pump is driven to supply ink to the liquid discharge head in a state where the ink held in the tank has been consumed and the remaining amount of ink is low, the path connecting the tank and the pump turns to a negative pressure state. There is a known technology that uses this phenomenon to detect a change in pressure in a path from a tank to a pump so as to detect the ink end.
Data Source
AI summary
A liquid discharge apparatus includes a liquid discharge head, a pump, tanks, a supply path, liquid supply regulators, a pressure detector, and control circuitry. The liquid supply regulators are provided for each of the tanks and configured to open and block the supply path to regulate supply of a liquid from the tanks to the liquid discharge head. The pressure detector is disposed between the liquid supply regulators and the liquid discharge head in the supply path. The control circuitry is configured to determine a low level tank among the tanks on basis of opening and closing conditions of the liquid supply regulators in a case where the pressure detector detects that a pressure of the supply path is lower than a predetermined value, and control the liquid supply regulators to supply the liquid from at least one tank of the tanks to the liquid discharge head.