Liquid ejecting head and liquid ejecting apparatus
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Solution Overview
Problem
The bonding of the flow path structure and the head chip with adhesive at perpendicular surfaces causes deformation due to adhesive shrinkage, leading to issues like denting of the fixing plate in liquid ejecting heads.
Innovation Solution
The head chip and flow path structure are coupled using an adhesive between the outer peripheral surface of a protruding flow path pipe and the inner peripheral surface of an opening, with the adhesive applied in a direction opposite to the flow path direction to prevent shrinkage-induced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow path structure and head chip are bonded together with adhesive at the surfaces perpendicular to the stacking direction, then the liquid-tight coupling is achieved, but the adhesive shrinkage causes deformation such as denting of the fixing plate
Solution Approach 1:
The patent changes the bonding dimension from perpendicular to stacking direction (Z-axis) to parallel to stacking direction (XY-plane). The flow path pipe protrudes in the stacking direction and is bonded to the flow path structure in a plane perpendicular to the stacking direction, so the adhesive shrinkage acts laterally rather than pushing the head chip toward the flow path structure, eliminating the denting problem while maintaining liquid-tight coupling
2Strength
If adhesive is used to couple the head chip and flow path structure, then the components are joined together, but the adhesive shrinkage induces stress causing deformation
Solution Approach 1:
The bonding interface is reoriented from a surface perpendicular to the stacking direction to a surface parallel to the stacking direction. The flow path pipe protrudes in the stacking direction, and the adhesive bonds the pipe to the flow path structure in a lateral plane. This dimensional change redirects the shrinkage stress away from the head chip assembly, preventing structural deformation while preserving joining strength
Solution Approach 2:
The flow path pipe acts as an intermediary element between the head chip and flow path structure. Instead of directly bonding the head chip to the flow path structure (which causes shrinkage-induced deformation), the pipe serves as a mediator that transfers the connection while its protruding geometry allows adhesive shrinkage to occur without affecting the head chip position, thus mediating between the need for strong bonding and the need to prevent deformation
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 minimizes deformation and enhances the structural integrity of the liquid ejecting head, improving the landing accuracy of droplets on the medium.
Implementation Method 1
the first flow path and the first coupling flow path are liquid-tightly coupled with the first adhesive disposed between an outer peripheral surface of the first flow path pipe and an inner peripheral surface of the first opening
Data Source
AI summary
A liquid ejecting head includes a head chip having a common liquid chamber that communicates with nozzles configured to eject a liquid in a first direction, and a flow path structure having a flow path that communicates with the common liquid chamber, in which the head chip has a flow path pipe that protrudes in a second direction opposite to the first direction from a surface facing the second direction and that has a coupling flow path communicating with the common liquid chamber inside, the flow path structure has an opening into which the flow path pipe is inserted, and the flow path and the coupling flow path are liquid-tightly coupled with an adhesive disposed between an outer peripheral surface of the flow path pipe and an inner peripheral surface of the opening.