Dual Pump Liquid Circulation Device for Ink Pressure Control
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in maintaining consistent liquid pressure in the nozzle due to changes in pump capacity over time, making it difficult to adjust and maintain optimal ink flow for printing.
Innovation Solution
A liquid circulation device with a dual pump system, including a first and second circulation pump, an adjustment tank, upstream and downstream tanks, pressure sensors, and a controller that adjusts pump voltages based on detected pressures to maintain optimal ink pressure in the nozzle, using piezoelectric pumps for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pump is used to circulate liquid and adjust pressure, then the apparatus structure is simple, but the liquid pressure cannot be maintained consistently when pump capacity changes over time
Solution Approach 1:
The circulation path is divided into two segments with two separate pumps (first circulation pump and second circulation pump) positioned on opposite sides of the liquid ejection head. This segmentation allows independent control of pressure on each side, enabling consistent liquid pressure maintenance even when individual pump capacities change over time.
Solution Approach 2:
The controller adjusts the rotation speeds of the first and second circulation pumps based on pressure feedback from pressure sensors, dynamically changing operational parameters to maintain target liquid pressure at the nozzle despite pump degradation or capacity variations.
2Duration of action of stationary object
If pump capacity changes over time, then the apparatus can operate for extended periods, but liquid pressure adjustment becomes difficult
Solution Approach 1:
Pressure sensors detect the actual liquid pressure in the circulation path, and the controller uses this feedback to automatically adjust the rotation speeds of the circulation pumps, maintaining target pressure without manual intervention even as pumps age and capacity changes.
Solution Approach 2:
The system performs self-adjustment of liquid pressure through automatic control of pump speeds based on pressure sensor feedback, eliminating the need for manual pressure adjustment operations and maintaining ease of operation throughout the apparatus lifespan.
3Reliability
If multiple tanks and pumps are added to control pressure, then liquid pressure can be maintained, but the apparatus size and complexity increase
Solution Approach 1:
The circulation tanks serve multiple functions: they act as reservoirs for liquid circulation, pressure adjustment chambers, and integration points for pump and sensor connections. This multi-functionality reduces the need for separate dedicated components, thereby limiting weight increase despite enhanced pressure control capabilities.
Solution Approach 2:
The first and second circulation pumps, along with pressure sensors and multiple tanks, are integrated into a unified circulation system where components share common mounting structures and fluid pathways, consolidating the overall apparatus footprint and weight while maintaining precise pressure control.
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 solution allows for precise control of ink pressure, preventing ink leakage and air bubble introduction, ensuring consistent printing quality even as pump quality degrades, and simplifies the apparatus design by integrating control components, reducing size, weight, and cost.
Implementation Method 1
using piezoelectric pumps for precise control
Implementation Method 2
a first pressure sensor configured to detect a pressure in the upstream tank, a second pressure sensor configured to detect a pressure in the downstream tank
Implementation Method 3
control the first and second pumps based on detected pressures in the upstream and downstream tanks
Data Source
AI summary
A liquid circulation device includes a circulation path through which a liquid circulates through a liquid ejection head, a first pump in the circulation path on a first side of the liquid ejection head, a second pump in the circulation path on a second side of the liquid ejection head, an adjustment tank in the circulation path between the first pump and the second pump, an upstream tank in the circulation path between the liquid ejection head and the first pump, a downstream tank in the circulation path between the liquid ejection head and the second pump, a first pressure sensor configured to detect a pressure in the upstream tank, a second pressure sensor configured to detect a pressure in the downstream tank, and a controller configured to control the first and second pumps based on detected pressures in the upstream and downstream tanks.