Ink Supply System Pulseless Flow and Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printers face pressure fluctuations due to diaphragm or impeller pumps, leading to non-uniform droplet sizes and quality issues, particularly in large scanning printhead applications, where complex systems with long tubes and heating components result in thermal losses and premature curing of UV inks.
Innovation Solution
An ink supply system with a recirculation tank, a recirculation pump, a heating assembly, and sensor assemblies with pressure and temperature sensors, coupled with a control system that adjusts pump speed and heating to maintain stable ink parameters, and an air pump for vacuum maintenance, allowing the system to travel with the printhead and include a bypass line for pressure regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If diaphragm or impeller pumps are used to circulate ink, then ink recirculation is achieved, but pressure fluctuations occur causing non-uniform droplet size
Solution Approach 1:
The harmful pulsing effect is extracted and eliminated by replacing the conventional diaphragm or impeller pump with a roller pump that provides continuous, pulseless ink circulation. This resolves the contradiction by maintaining recirculation functionality while removing the pressure fluctuations that cause droplet size variation.
Solution Approach 2:
The pumping mechanism is changed from a positive displacement type (diaphragm/impeller) to a roller pump that creates continuous flow. This parameter change in the pump operation mode eliminates pressure pulsations while maintaining ink recirculation, thereby achieving both productivity and droplet uniformity.
2Manufacturing precision
If pressure regulating components are added to remediate pressure fluctuations, then droplet uniformity improves, but system complexity increases
Solution Approach 1:
Instead of adding complex pressure regulating components to an existing pump system, the solution extracts and replaces the pump itself with a roller pump that inherently provides pulseless flow. This eliminates the need for additional pressure regulation components, maintaining simplicity while achieving droplet uniformity.
3Productivity
If long tubes are used to connect stationary recirculation tank to scanning printhead, then recirculation is maintained, but thermal losses increase causing ink temperature instability
Solution Approach 1:
The recirculation tank is relocated from a stationary position to travel with the printhead in the scanning direction. This dimensional change in the tank's position allows the ink circulation path to be significantly shortened, reducing thermal losses while maintaining recirculation functionality.
4Use of energy by stationary object
If recirculation tank and heating components are made stationary, then thermal management is simplified, but system weight increases making carriage mounting impractical
Solution Approach 1:
The recirculation tank transitions from a stationary component to a moving component that travels with the printhead on the carriage. This dimensional change in mobility allows the system to achieve effective thermal management through reduced tube lengths while keeping the moving mass low enough for practical carriage mounting.
5Temperature
If heating power is increased to compensate for thermal losses, then ink temperature is maintained, but UV curable inks overheat causing premature curing
Solution Approach 1:
By relocating the recirculation tank to travel with the printhead, the ink circulation path is shortened, reducing thermal losses. This allows maintenance of ink temperature with lower heating power, preventing overheating and premature curing of UV inks while still achieving effective temperature 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 system provides a pulseless ink flow, maintaining consistent droplet sizes and preventing overheating, resulting in improved print quality and reduced system complexity, weight, and cost, suitable for scanning printhead applications.
Implementation Method 1
a heating assembly having an ink conduit formed into a spiral in thermal contact with at least one heating element
Implementation Method 2
An air pump is coupled to the recirculation tank in order to maintain a substantial vacuum within the tank
Data Source
Figure 1
Figure 2~5
Figure 3~3A
AI summary
An ink supply system (100) for ink jet printers includes a recirculation tank (101) coupled to a recirculation pump (111) configured to provide a substantially pulseless flow of ink. A heating assembly (115) having an ink conduit formed into a spiral in thermal contact with at least one heating element receives ink from the pump (111) and outlets to a sensor assembly (103) with temperature and pressure sensors (105,107) that measure ink parameters both as the ink enters a printhead (109) and is returned from the printhead (109). The returned ink is then ported to a recirculation tank (101) from which the pump (111) draws the recirculating ink. An air pump (119) is coupled to the recirculation tank (101) in order to maintain a substantial vacuum within the tank (101)