Ink-jet Head Caps with Variable Hardness for Sealing
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Solution Overview
Problem
Conventional image recording apparatuses with ink-jet heads face issues such as ink ejection failures due to broken ink meniscuses, especially when nozzles are divided into groups with varying nozzle diameters and ink properties, leading to inconsistent sealing and increased costs from higher pressing forces required for adequate contact.
Innovation Solution
The apparatus employs caps with different hardness levels, where caps covering nozzles with lower breakdown pressure are made softer and those with higher breakdown pressure are made harder, ensuring reliable sealing without the need for increased pressing forces, thus preventing ink ejection failures and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same pressing force is applied to all caps, then the device complexity is reduced, but the sealing performance becomes insufficient for nozzles with low breakdown pressure
Solution Approach 1:
The patent applies local quality by making each cap's hardness match the specific requirements of the nozzle group it covers. Caps for nozzles with low breakdown pressure are made softer, while caps for nozzles with high breakdown pressure are made harder. This localized customization of cap properties ensures optimal sealing performance for each nozzle group without requiring a completely different cap design for each nozzle, thus maintaining reasonable device complexity while significantly improving reliability.
Solution Approach 2:
The patent changes the hardness parameter of caps based on the breakdown pressure characteristics of different nozzle groups. By adjusting this physical parameter of the cap material, the system achieves different sealing performances tailored to specific nozzle requirements. This parameter-based differentiation allows the same cap structure to serve multiple nozzle groups with varying characteristics, improving sealing reliability without proportionally increasing device complexity.
2Reliability
If the pressing force is increased to improve sealing, then the sealing performance is improved, but the ink-jet head may suffer from deformation or distortion
Solution Approach 1:
The patent applies local quality by customizing cap hardness to match the specific sealing requirements of each nozzle group. Softer caps are used for nozzles requiring gentler contact, while harder caps are used for nozzles that can tolerate higher pressing forces. This localized adaptation ensures adequate sealing performance for each group without subjecting the entire ink-jet head to uniformly high pressing forces, thereby preventing deformation or distortion of the plate-type head structure.
Solution Approach 2:
The patent implements beforehand cushioning by pre-configuring caps with appropriate hardness levels before they contact the nozzles. By selecting cap materials with suitable hardness in advance, the system provides built-in protection against excessive pressing forces that could damage the ink-jet head. This preventive approach ensures that even when pressing forces are applied to achieve sealing, the force is appropriately moderated by the cap's mechanical properties, protecting the head from deformation.
3Reliability
If harder caps are used to improve sealing, then the sealing performance is improved, but the ink meniscuses with low breakdown pressure may be broken
Solution Approach 1:
The patent applies local quality by matching cap hardness to the specific characteristics of each nozzle group. For nozzles with low breakdown pressure, softer caps are selected to provide gentle sealing that prevents meniscus breakdown. For nozzles with high breakdown pressure, harder caps are used to achieve adequate sealing. This localized matching of cap properties to nozzle characteristics ensures that sealing is achieved without applying excessive force that would break vulnerable ink meniscuses.
Solution Approach 2:
The patent changes the hardness parameter of caps based on the breakdown pressure characteristics of different nozzle groups. By adjusting this physical parameter, the system achieves optimal balance between sealing performance and meniscus protection. Softer caps (lower hardness parameter) are used for delicate nozzles, while harder caps (higher hardness parameter) are used for robust nozzles, ensuring that sealing effectiveness is optimized without causing harmful meniscus breakdown.
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
This approach enhances the sealing performance and reliability of ink ejection across various nozzle groups, preventing ink meniscus breakdown and maintaining high utility without distorting the ink-jet head, even with a plate-type head of small thickness.
Implementation Method 1
The cap is held in close or intimate contact with the nozzle opening surface owing to elastic deformation of its peripheral portion
Implementation Method 2
there is known one equipped with a purge device for discharging air-bubbles, poor-quality ink and the like accumulated in the ink-jet head, thereby restoring ink ejecting performance of the ink-jet head
Data Source
AI summary
An image recording apparatus including: an ink-jet head having a plurality of nozzles which are open in a surface thereof so as to provide a nozzle opening surface and through which ink is ejected, the plurality of nozzles being divided into a plurality of nozzle groups: and a plurality of caps which are provided in correspondence with the plurality of nozzle groups, each of which is formed of an elastic material, each of which has a peripheral portion that comes into close contact with the nozzle opening surface at an end thereof, and which are capable of covering the nozzle opening surface such that the peripheral portion of each of the plurality of caps surrounds nozzles which constitute a part of the plurality of nozzles and which belong to a corresponding one of the plurality of nozzle groups, wherein a first cap among the plurality of the caps has a hardness higher than that of a second cap which is different from the first cap.