Printhead Cleaning System Using Electrostatic Droplet Steering
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Solution Overview
Problem
During 3D printing operations, build material particles and debris adhere to the printhead surface and can clog the bores, disrupting the firing of printing liquid, as existing cleaning methods often apply cleaning fluid into the firing chambers, causing damage or inefficiency.
Innovation Solution
A cleaning system that uses pressurized cleaning fluid sprayed through nozzles positioned to avoid the firing chambers, with optional angling and rotation to target the surface effectively, and includes a charging electrode and deflector plate to steer droplets for precise cleaning without entering the bores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cleaning fluid is applied to the printhead surface using conventional methods, then the build material particles and debris are removed from the surface, but the cleaning fluid enters the firing chambers through the bores causing damage or inefficiency
Solution Approach 1:
A charging electrode and deflector plate are introduced as intermediary components between the cleaning fluid source and the printhead surface. The charging electrode imparts electrical charge to the cleaning fluid droplets, and the deflector plate uses electrostatic forces to steer the charged droplets away from the bores and onto the surface, preventing fluid from entering the firing chambers while still achieving cleaning.
Solution Approach 2:
The conventional mechanical spray system is replaced with an electrostatically controlled fluid delivery system. Instead of relying solely on mechanical pressure and direction control, the system uses electrical charging and electrostatic deflection to precisely control where the cleaning fluid lands, substituting mechanical control with electrical field control.
2Productivity
If pressurized cleaning fluid is sprayed onto the printhead surface, then debris is removed effectively, but the bores may become clogged with particles or disrupted by fluid pressure
Solution Approach 1:
The deflector plate serves as an intermediary that separates the cleaning fluid trajectory from the bores. By positioning the deflector plate to intercept and redirect charged droplets, it ensures that cleaning fluid is deposited on the surface between or away from the bores, preventing both clogging and pressure disruption while maintaining cleaning effectiveness.
Solution Approach 2:
The cleaning action is localized to specific areas of the printhead surface that do not contain bores. The charging electrode and deflector plate system creates zones of charged droplet deposition that are spatially separated from the bore locations, allowing intensive cleaning in safe zones while leaving the bore areas undisturbed.
3Measurement precision
If nozzles are positioned close to the printhead surface for precise cleaning, then surface coverage is improved, but the risk of fluid entering the bores increases
Solution Approach 1:
The system replaces mechanical positioning precision with electrostatic control precision. Instead of relying on the physical alignment and spacing of nozzles relative to the printhead surface, the system uses electrical charging and field-based deflection to achieve sub-millimeter precision in droplet placement, allowing the nozzle to be positioned closer to the surface without increasing fluid intrusion risk.
Solution Approach 2:
The deflector plate acts as an intermediary safety barrier between the closely positioned nozzle and the bores. Even when the nozzle is positioned close to the surface for precise cleaning coverage, the deflector plate intercepts any droplets that might otherwise enter the bores, redirecting them onto the surface instead.
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
Effectively removes build material particles and debris from the printhead surface without clogging the firing chambers, maintaining printhead performance and preventing damage from cleaning fluids.
Implementation Method 1
In some examples, a charging electrode and a deflector plate may be used to electrically charge and steer droplets of the pressurized cleaning fluid to intended locations on the surface.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C
AI summary
According to an example, an apparatus may include a printhead to deliver a printing liquid from firing chambers through a plurality of bores arranged along a surface of the printhead. The apparatus may also include a cleaning system to apply a pressurized cleaning fluid onto the surface of the printhead while preventing application of the pressurized cleaning fluid into the firing chambers through the plurality of bores.