Inkjet Printer Ink Circulation Viscosity Control
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Solution Overview
Problem
Inkjet printers face issues with ink temperature drops due to long intervals in circulation, leading to varying ink viscosities and flow rates, which cause instability in the ink tank's liquid surface and potential air mingling in the ink supplied to the inkjet head, especially at low temperatures.
Innovation Solution
An inkjet printer design with an ink tank and inkjet head configuration that includes an air layer and flow rate difference reducers, using temperature controllers and heaters to maintain adequate ink temperatures and reduce viscosity differences between upstream and downstream inks, preventing air mingling by controlling the flow rates and heating the ink circulation route.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ink is circulated through the ink circulation route, then ink temperature is maintained, but ink viscosity varies at different locations due to heating intervals
Solution Approach 1:
The patent applies local quality by creating different flow path configurations for upstream and downstream ink flows. The downstream ink flow path has a larger cross-sectional area than the upstream ink flow path, which compensates for the viscosity difference caused by selective heating. This local structural variation ensures uniform flow rates despite temperature-induced viscosity changes at different locations in the ink circulation route.
2Stability of the object's composition
If upstream ink is heated more than downstream ink, then upstream ink viscosity decreases, but flow rate difference between upstream and downstream ink increases
Solution Approach 1:
The patent applies asymmetry by designing the downstream ink flow path with a larger cross-sectional area compared to the upstream ink flow path. This asymmetric configuration compensates for the viscosity reduction in upstream ink caused by heating. The larger downstream path area reduces flow resistance, balancing the flow rates between upstream and downstream sections despite the viscosity difference created by selective heating.
3Loss of energy
If ink circulation is interrupted for long intervals, then energy consumption is reduced, but ink temperature drops and viscosity increases
Solution Approach 1:
The patent applies preliminary action by pre-heating the upstream ink before it reaches the inkjet head. The heating section is positioned upstream in the circulation route, so ink is heated in advance during circulation. This ensures that even after long intervals without circulation, the ink maintains adequate temperature and viscosity when it reaches the inkjet head, reducing the need for intensive post-warmup heating.
4Speed
If ink viscosity varies along the circulation route, then flow rates become unstable, but air may be drawn into the ink tank
Solution Approach 1:
The patent applies parameter changes by modifying the cross-sectional area parameter of the ink flow paths. The downstream ink flow path is designed with a larger cross-sectional area than the upstream path, which changes the flow dynamics to compensate for viscosity variations. This parameter adjustment ensures stable flow rates and prevents air from being drawn into the ink tank by maintaining balanced pressure and flow conditions throughout the circulation system.
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 effectively prevents air from being supplied to the inkjet head, ensuring stable ink flow and accurate printing even at low temperatures by maintaining consistent ink viscosities and flow rates, thus enhancing the printer's operational accuracy and reliability.
Implementation Method 1
a heater configured for heating the upstream ink in the ink circulation route, and a temperature controller configured for controlling an amount of thermal energy to be outputted by the heater, equalizing a viscosity of the upstream ink with a viscosity of the downstream ink
Implementation Method 2
supply ink from an upper ink tank to a lower ink tank through an ink circulation route, with pressures corresponding to differences in water head of liquid level in between
Data Source
AI summary
Streams of ink being returned by a circulation pump from a lower tank through an upstream flow path block to an upper tank have viscosities higher than viscosities of streams of ink being supplied from the upper tank through a downstream flow path block to an inkjet head, there being a difference in flow rate of ink developed with attendant differences in viscosity between the upstream flow path block and the downstream flow path block, while being reduced by differences between heating efficiencies in the upstream flow path block and heating efficiencies in the downstream flow path block.