Liquid Ejecting Head Sheet Heater Overlap Design
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Solution Overview
Problem
Existing liquid ejecting heads with sheet-shaped heaters face a challenge in minimizing size due to the need for routing relay wiring around resistance wires, which occupies additional space.
Innovation Solution
The liquid ejecting head incorporates a sheet-shaped heater with a resistance wire on one surface and relay wiring on the opposite surface, allowing them to overlap in the thickness direction, thus minimizing the heater's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If relay wiring is disposed on the same surface as the resistance wire, then the heater structure is simpler, but the heater size increases due to the need for bypass routing
Solution Approach 1:
The patent applies dimensionality change by moving the relay wiring from the same surface (2D plane) to the opposite surface of the heater, utilizing the third dimension (thickness direction) to resolve the spatial conflict. This allows the relay wiring to overlap the resistance wire when viewed from the thickness direction, eliminating the need for bypass routing and reducing the heater's planar area while maintaining electrical connectivity.
2Reliability
If relay wiring is routed to bypass the resistance wire, then electrical isolation is maintained, but the heater area increases
Solution Approach 1:
The patent resolves the electrical isolation requirement by utilizing the thickness direction to separate the resistance wire and relay wiring onto opposite surfaces of the heater. This spatial separation in the third dimension maintains electrical isolation while allowing the wiring to overlap in the planar view, thereby eliminating the need for bypass routing and reducing the overall heater area.
Solution Approach 2:
The heater substrate itself acts as an intermediary that provides both mechanical support and electrical isolation between the resistance wire and relay wiring. By disposing these conductive elements on opposite surfaces of the insulating heater substrate, the patent achieves electrical isolation without requiring additional bypass routing, thus minimizing the heater area.
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 enables a more compact liquid ejecting head design without increasing the size, allowing for efficient heating and temperature detection while maintaining the apparatus's functionality.
Implementation Method 1
a resistance wire disposed on the first surface and configured to heat a heating target being a portion of the liquid ejecting head
Implementation Method 2
relay wiring electrically connected to the temperature detection element and disposed on the second surface
Data Source
AI summary
A liquid ejecting head includes: a nozzle; and a sheet-shaped heater for heating the liquid to be supplied to the nozzle, and the heater includes a main surface portion having a temperature detection element, an insulative first base member having a first surface and a second surface on an opposite side of the first surface, a resistance wire disposed on the first surface and configured to heat a heating target being a portion of the liquid ejecting head, and relay wiring electrically connected to the temperature detection element and disposed on the second surface, and the resistance wire overlaps the relay wiring when viewed in a thickness direction of the main surface portion.