Liquid Ejecting Head Nozzle Surface Contact Angle Control
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Solution Overview
Problem
Liquid tends to remain on the nozzle surface of liquid ejecting heads due to the stepped edge between the anchoring plate and the nozzle surface, leading to potential dripping onto recording paper, clogging of nozzles, and drying issues when a capping member is employed, resulting in soiled paper and ejection malfunctions.
Innovation Solution
The liquid ejecting apparatus is designed with a configuration where the angle of contact between the nozzle surface and liquid is greater than 90 degrees, while the anchoring plate and wiper member have angles of contact less than 90 degrees with the liquid, facilitating liquid movement away from the nozzle surface. A gap between the anchoring plate and nozzle formation member can be filled with a filler, and the wiper member is made of an elastic material to enhance contact tightness and prevent liquid adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stepped edge is formed at the opening region in the anchoring plate, then the nozzle surface is exposed for liquid ejection, but liquid accumulates in the corner of the stepped area and remains on the nozzle surface
Solution Approach 1:
The patent inverts the conventional wiping direction by making the wiper member move from the nozzle surface side toward the anchoring plate side, opposite to the traditional approach. This reversal prevents liquid from being pushed onto the nozzle surface during wiping, effectively eliminating liquid accumulation at the stepped edge while maintaining proper ejection function
Solution Approach 2:
The patent changes the contact angle parameter between the wiper member and liquid to be greater than 90 degrees, making the wiper surface liquid-repellent. This parameter change ensures that liquid does not adhere to the wiper member during the wiping process, preventing liquid from being transferred to and remaining on the nozzle surface
2Ease of manufacture
If the wiper member makes tight contact with the anchoring plate during wiping, then liquid is effectively wiped from the anchoring plate, but liquid adheres to the front surface of the wiper member and accumulates at the stepped area
Solution Approach 1:
The patent changes the contact angle parameter between the wiper member and liquid to be greater than 90 degrees, making the wiper surface liquid-repellent. This parameter change ensures that liquid does not adhere to the wiper member during the wiping process, preventing liquid from being transferred to and accumulating on the nozzle surface
Solution Approach 2:
The patent employs composite material structure for the wiper member, combining an elastic base material with a liquid-repellent surface coating or treatment. This composite approach maintains the elasticity needed for tight contact with the anchoring plate while the liquid-repellent surface prevents liquid adhesion
3Reliability
If liquid remains on the nozzle surface, then ejection malfunction and nozzle clogging occur, but modifying the anchoring plate structure to eliminate the step increases device complexity
Solution Approach 1:
The patent introduces a wiper member as an intermediary element between the anchoring plate and the nozzle surface. This intermediary performs the function of removing liquid from the system, allowing the anchoring plate to maintain its simple stepped structure while still achieving reliable ejection by preventing liquid accumulation
Solution Approach 2:
The wiper member is designed to automatically wipe the anchoring plate and prevent liquid accumulation during normal operation without requiring additional cleaning mechanisms or complex structural modifications to the anchoring plate itself
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 configuration effectively suppresses liquid from remaining on the nozzle surface, preventing soiling of recording paper and nozzle clogging, while allowing for efficient ink ejection and reduced risk of liquid accumulation.
Implementation Method 1
when an angle of contact between the nozzle surface and the liquid is taken as θn, an angle of contact between the anchoring plate exposed-surface and the liquid is taken as θs, and an angle of contact between the wiper member and the liquid is taken as θw, the relationship θn>θs>θw>90° is fulfilled
Implementation Method 2
an angle of contact between the nozzle surface and the liquid is taken as θn, an angle of contact between the anchoring plate exposed-surface and the liquid is taken as θs, and an angle of contact between the wiper member and the liquid is taken as θw
Implementation Method 3
the wiper member is made of an elastic material to enhance contact tightness and prevent liquid adherence
Data Source
AI summary
A liquid ejecting apparatus includes a head unit capable of ejecting a liquid from a nozzle provided in a nozzle surface of a nozzle plate, an anchoring plate in which the head unit is anchored and that is provided with an opening region that exposes the nozzle surface, and a wiper member that wipes an anchoring plate exposed-surface located on the opposite side of the head unit of the anchoring plate and the nozzle surface. When an angle of contact between the nozzle surface and the liquid is taken as θn, an angle of contact between the anchoring plate exposed-surface and the liquid is taken as θs, and an angle of contact between the wiper member and the liquid is taken as θw, the relationship θn>θs>θw>90° is fulfilled.