Printhead Capping Station with Movable Planar Plate
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Solution Overview
Problem
Inkjet imaging devices face issues with quickly drying inks, where the solvent in the ink evaporates quickly, leading to increased viscosity and clogging of nozzles, resulting in the need for frequent purging operations that waste ink and do not effectively maintain a low viscosity state during printhead inactivity.
Innovation Solution
A capping station with a planar member that moves between positions to mate with the printhead, using a hydrophilic planar protecting plate to enclose the printhead and maintain a low viscosity state by minimizing evaporation, comprising a printhead receptacle with an opening corresponding to the printhead perimeter, and actuators to control the movement of the planar member and printhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the printhead is left exposed during inactivity, then the device structure remains simple, but the ink viscosity increases due to evaporation causing nozzle clogging
Solution Approach 1:
The patent employs a thin planar protecting plate that covers the printhead nozzles during inactivity. This plate acts as a barrier to prevent ink evaporation while maintaining a relatively simple device structure. The plate is moved into position over the printhead face when the printhead is not in use, effectively sealing the nozzles without requiring a complex enclosure system.
Solution Approach 2:
The capping station uses movable components including a planar protecting plate and applicator arm that can dynamically position themselves. The protecting plate is movable between a stored position and a covering position over the printhead. This dynamic configuration allows the system to provide protection only when needed, avoiding the complexity of a permanently enclosed structure.
2Reliability
If purging operations are performed frequently to maintain low viscosity, then nozzle clogging is reduced, but ink is wasted and operational time is lost
Solution Approach 1:
The system performs preliminary action by applying a liquid film to the planar protecting plate before it covers the printhead. This pre-applied liquid layer prevents ink evaporation at the nozzle interfaces, maintaining low viscosity without requiring subsequent purging operations. The liquid film is replenished as needed to ensure continuous protection during inactivity periods.
Solution Approach 2:
The patent converts the potentially harmful effect of liquid application (which could cause pooling or interference with printing) into a beneficial protective measure. By applying liquid to the protecting plate rather than directly to the nozzles, the system prevents evaporation and maintains ink flow readiness without the negative effects of direct nozzle flooding. The liquid on the plate surface creates a controlled environment that benefits ink preservation.
3Object-affected harmful factors
If a traditional cap enclosure is used, then evaporation is reduced, but ink pooling occurs at the nozzle edges due to surface tension
Solution Approach 1:
The patent applies local quality by using a hydrophilic planar protecting plate with specific surface properties. The plate is made hydrophilic in the regions that contact the ink to promote uniform spreading and prevent edge pooling. This localized surface treatment ensures that ink or liquid applied to the plate distributes evenly across the surface rather than concentrating at the nozzle perimeters, eliminating the clogging problem while maintaining evaporation protection.
Solution Approach 2:
The system changes the surface energy parameter of the protecting plate by making it hydrophilic. This parameter change affects how liquid interacts with the plate surface, promoting uniform distribution and preventing the edge pooling that occurs with hydrophobic surfaces. The hydrophilic treatment modifies the contact angle and surface tension characteristics to achieve controlled liquid behavior that protects against both evaporation and pooling.
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 reduces ink evaporation at the nozzles, maintaining a low viscosity state and minimizing the need for purging, thereby preserving the operational status of inkjets and conserving ink during periods of inactivity.
Implementation Method 1
the solvent in the ink evaporates quickly, leading to increased viscosity and clogging of nozzles
Implementation Method 2
using a hydrophilic planar protecting plate to enclose the printhead and maintain a low viscosity state by minimizing evaporation
Data Source
AI summary
An inkjet printer is configured with capping stations for storing printheads in the printer during periods of printer inactivity so the viscosity of the ink in the nozzles of the inkjets of the printheads does not increase significantly. Each capping station has a printhead receptacle that encloses a volume, a planar member configured to move between a first position at which the planar member is located within the printhead receptacle and a second position at which the planar member is external of the printhead receptacle, a first actuator operatively connected to the planar member, the first actuator being configured to move the planar member from the first position to the second position, and a controller configured to operate the first actuator to move the planar member from the first position to the second position to mate the planar member with a face of a printhead.