Print Head Valve Assembly with Electromagnetic Stopper
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Solution Overview
Problem
Drop-on-demand inkjet printers suffer from low vertical resolution due to the large size of solenoids in valve assemblies, which can lead to clogging issues when using quick-drying inks, and previous solutions either require frequent adjustments or increase heating and costs.
Innovation Solution
A print head design featuring a valve assembly with a stopper and arm mechanism, where the arm is pivoted by an electromagnet to control ink flow through nozzles, utilizing a biasing member to close the nozzle and allowing for high-speed operation with aqueous or solvent-based inks, and the ability to be dismantled and refurbished.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solenoids are used in valve assemblies to control ink flow, then reliable ink flow control is achieved, but vertical resolution deteriorates due to large solenoid size
Solution Approach 1:
The patent replaces the traditional solenoid actuator with a piezoelectric actuator that directly deforms the valve body to open or close the ink ejection hole. This eliminates the need for mechanical linkages and reduces the overall size of the valve assembly, thereby improving vertical resolution while maintaining reliable ink flow control through direct piezoelectric deformation of the valve structure.
2Manufacturing precision
If solenoid size is reduced to improve resolution, then vertical resolution improves, but heating effect increases and cost increases
Solution Approach 1:
The patent substitutes the solenoid-based electromagnetic actuation system with a piezoelectric actuation system. The piezoelectric material converts electrical energy directly into mechanical deformation of the valve body without generating significant heat, thus improving resolution while avoiding the heating problems associated with miniaturized solenoids.
3Manufacturing precision
If flexible tubes are used to couple solenoids to nozzles, then nozzle spacing can be reduced, but tube clogging occurs with quick drying ink
Solution Approach 1:
The patent eliminates the flexible tube coupling by integrating the ink delivery path directly into the valve body structure. The ink flows directly from the supply through the valve body to the ejection hole without intermediate tubes, thereby preventing clogging while maintaining close nozzle spacing through the compact integrated design.
Solution Approach 2:
The patent merges the ink delivery channel and valve structure into a single integrated valve body. This eliminates the separate flexible tube component and creates a direct fluid path from ink supply to nozzle, preventing clogging issues while achieving compact nozzle spacing through structural integration.
4Manufacturing precision
If wire coupling with moving ink seal is used to connect remote solenoid, then resolution improves, but frequent adjustment is required
Solution Approach 1:
The patent replaces the wire coupling with moving ink seal system by using a piezoelectric actuator that directly deforms the valve body. This eliminates the need for moving seals and wire adjustments, providing both high resolution and low maintenance through direct piezoelectric actuation of the ink ejection hole closure.
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 design improves resolution, minimizes adjustment needs, operates at high speeds, and prevents clogging by eliminating the need for tubes between valves and nozzles, while being compatible with various ink types and allowing for easy maintenance.
Implementation Method 1
one or more coils for selectively inducing a magnetic flux in the circuit in order to move the arm between a position in which it closes the respective orifice and a position in which it opens the orifice
Implementation Method 2
A biasing member is positioned adjacent the arm and configured to move the arm away from the electromagnet to close the nozzle
Data Source
AI summary
A print head includes a fluid cavity and nozzle in fluid communication with the fluid cavity. A stopper is positioned adjacent the nozzle and adapted to control flow of fluid through the nozzle. An arm supports the stopper and is configured to pivotally move the stopper with respect to the nozzle. An electromagnet is positioned adjacent the arm and configured to move the arm toward the electromagnet to open the nozzle.