Liquid Ejecting Head Channel Segmentation for Ink Flow
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Solution Overview
Problem
Conventional liquid ejecting heads face challenges in flowing a large amount of liquid into the supply and return channels without increasing the differential pressure between the supply and return ports, which can lead to ink meniscus breakage, air bubbles, and ink leakage.
Innovation Solution
The liquid ejecting head incorporates a channel structure with multiple individual channels and connecting channels that allow liquid to flow from the supply channel to the return channel without external ejection, positioned to reduce pressure differences and facilitate ink flow, while dummy channels are strategically placed to enhance ink distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the differential pressure between the supply port and the return port is increased to allow a large amount of ink to flow into the supply manifold and return manifold, then the ink flow rate is improved, but the ink meniscus may break causing air bubbles to enter the channels and/or ink to leak from the nozzle
Solution Approach 1:
The patent divides the single supply manifold and return manifold into multiple smaller channels (first supply channels, second supply channels, first return channels, second return channels). This segmentation reduces the pressure loss in each individual channel, allowing a large amount of ink to flow without requiring excessive differential pressure that would break the ink meniscus. The multiple channels work in parallel to achieve high flow rate while maintaining stable pressure at the nozzle.
2Device complexity
If dummy channels are connected to the location in the vicinity of the other end of the supply manifold, then the channel structure is simplified, but the amount of ink flowing from the supply port to the supply manifold is hardly increased due to pressure loss
Solution Approach 1:
The patent applies different connection locations for different types of channels based on their specific functions. Individual channels are connected to supply channels at locations that optimize ink distribution to nozzles, while dummy channels are connected to return channels at locations that optimize air bubble discharge. This local optimization ensures that each channel type performs its specific function efficiently without compromising overall system performance.
3Productivity
If individual channels are formed to allow ink to flow from the supply manifold to the return manifold, then the ink flow distribution is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated channel structures. The supply channels and return channels are arranged in parallel pairs, with individual channels connecting corresponding supply and return channels. Dummy channels are integrated into the return channel system to perform dual functions of ink return and air bubble discharge. This merging approach achieves improved ink flow distribution while minimizing the increase in device complexity through efficient spatial arrangement and multi-function integration.
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 significant increase in ink flow into the supply and return channels while maintaining stable pressure at the nozzle meniscus, effectively preventing air bubbles and ink leakage, and ensuring efficient ink distribution across the head.
Implementation Method 1
a differential pressure (the pressure in the supply port is greater than the pressure in the return port) is generated by a pump between the supply port and the return port
Implementation Method 2
the supplied ink flows in the supply manifold along the first direction from the one end toward the other end. Afterwards, the ink flows through the bypass channel and flows in the return manifold along the first direction from the other end toward the one end
Data Source
AI summary
A liquid ejecting head includes a channel structure having a first channel group. The first channel group includes: a supply channel extending in a first direction from one end thereof provided with a supply port, a return channel extending in the first direction from one end thereof provided with a discharge port and arranged side by side with the supply channel in a second direction, first individual channels aligned in the first direction, a second individual channel having one end communicating with the supply channel and the other end communicating with the return channel, and a connecting channel connecting the other end in the first direction of the supply channel and the other end in the first direction of the return channel. The second individual channel causes liquid to flow from the supply channel to the return channel, without causing the liquid to be ejected outside.