Variable-Force Printhead Cap for Nozzle Dry-Out and Priming
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Solution Overview
Problem
Existing printhead systems face issues with nozzle dry-out and air ingestion due to exposure to undesirable environmental conditions, leading to non-uniform printing and potential damage to printhead components, particularly during priming cycles.
Innovation Solution
A multi-force printhead cap system with a variable force capping station that applies a first force when idle and a higher second force during priming, using an elastomer seal and nonlinear springs to maintain a controlled environment and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant high capping force is applied to prevent nozzle dry-out, then nozzle protection is improved, but printhead damage risk increases during priming
Solution Approach 1:
The patent applies a variable capping force that dynamically adjusts between a first force level during idle states and a second reduced force level during priming operations. This dynamic adjustment prevents nozzle dry-out during idle periods while minimizing stress on the printhead during priming, thereby resolving the contradiction between nozzle protection and printhead durability.
2Reliability
If a constant high capping force is applied to maintain controlled environment, then nozzle dry-out prevention is improved, but air ingestion risk increases during priming
Solution Approach 1:
The system dynamically adjusts the capping force to a reduced second force during priming operations, which allows air to be effectively purged from the system without causing excessive stress that would lead to air ingestion. During idle states, the higher first force maintains the controlled environment and prevents nozzle dry-out, thus resolving the contradiction between dry-out prevention and air ingestion risk.
3Reliability
If high capping force is applied continuously, then seal effectiveness is improved, but printhead stress increases
Solution Approach 1:
The patent implements periodic adjustment of capping force levels based on operational state. A higher first force is applied during idle periods to maintain seal effectiveness and prevent nozzle dry-out, while a reduced second force is applied during priming operations to minimize printhead stress. This periodic variation resolves the contradiction between maintaining seal effectiveness and reducing continuous stress on the printhead.
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 system effectively prevents nozzle dry-out and air ingestion, ensuring consistent print quality and extending printhead life by minimizing exposure to high forces during infrequent priming events.
Implementation Method 1
A variable force printhead cap system with an elastomer cap supported by a compression spring, capable of exerting different capping forces
Implementation Method 2
A cap with an elastomer seal to surround a printhead die on a print cartridge
Data Source
AI summary
In one example in accordance with the present disclosure, a printhead cap system is described. The printhead cap system includes a cap having an elastomer seal to surround a printhead die on a print cartridge. The printhead cap system also includes a variable force capping station to retain the cap. The variable force capping station is to move the cap to 1) a first position wherein the cap exerts a first force on a substrate on which the printhead die is disposed and 2) a second position wherein the cap exerts a second force on the substrate. In an example, the second force is greater than the first force. The printhead cap system also includes a control system to raise the cap from an uncapped position through the first position and the second position.