Liquid Ejection Head Channel Segmentation for Bubble Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid ejecting heads experience ejection failures due to air bubbles in connecting channels, leading to inconsistent droplet volume, waveform control issues, and positional deviations in inkjet printing, resulting in wrinkles, overlapping droplets, and dot omissions.
Innovation Solution
A liquid ejecting head design featuring a channel forming body with individual channels, nozzles, pressure chambers, descenders, return channels, and communicating channels, where the return channels and communicating channels are arranged to facilitate equal liquid flow and reduce air bubble stagnation, ensuring consistent ejection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If individual recovery channels are connected by a connecting channel, then liquid can be recovered from multiple channels, but air bubbles stagnate in the connecting channel causing ejection failures
Solution Approach 1:
The patent divides the connecting channel into multiple separate communicating channels, each connecting adjacent individual recovery channels to the common recovery channel independently. This segmentation prevents air bubbles from stagnating in a single long connecting channel, as each shorter communicating channel can be individually managed for bubble removal, thus maintaining reliable ejection performance while enabling liquid recovery.
2Reliability
If air bubbles are present in the connecting channel, then resonance frequency changes occur, but droplet volume control and waveform timing become inaccurate
Solution Approach 1:
The patent extracts the air bubble problem from the main ejection channels by providing separate communicating channels for recovery. Air bubbles are confined to these dedicated recovery channels rather than affecting the main ejection channels, allowing resonance frequency to remain stable in the ejection channels while bubbles are managed separately, thus preserving both frequency stability and droplet volume control precision.
3Stress or pressure
If liquid flows through connecting channels, then pressure equalization occurs, but air bubbles remain trapped causing ejection inconsistencies
Solution Approach 1:
The patent introduces a common recovery channel as an intermediary that collects liquid from multiple individual recovery channels through separate communicating channels. This intermediary structure allows pressure equalization to occur in the recovery system without requiring liquid to flow through a long connecting channel that would trap air bubbles, thereby maintaining ejection consistency while achieving pressure balance.
Data Source
AI summary
A liquid ejecting head includes a channel forming body including a plurality of individual channels, a first manifold and a second manifold. The plurality of individual channels includes: a nozzle; a pressure chamber which is arranged to be apart from the nozzle in a first direction; a descender communicating the pressure chamber and the nozzle with each other, and extending in the first direction; a return channel including a first return channel and a second return channel, extending in a direction crossing the first direction, and having one end connected to the descender; and a communicating channel including a first communicating channel, and connecting the other end of the return channel to the second manifold. The first communicating channel connects the first return channel to the second manifold and connects the second return channel to the second manifold.