Inkjet Head Flow Channel Resistance Ratios for Bubble Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-density arrays of nozzles in conventional inkjet heads with circulating channels result in significant variance in ink flow among individual communication flow channels, leading to reduced ejection energy efficiency and variance in ink ejection performance due to increased flow rates expelling air bubbles and foreign materials.
Innovation Solution
An inkjet recording apparatus with a specific configuration of individual and common flow channels, where the ink amount ejected per unit time from nozzles and the flow resistance ratios satisfy Fn / Fi ≤ 10 and Rc / Rt ≤ 10, along with a damper in the common flow channel for elastic deformation, to maintain stable ink ejection and expel air bubbles effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow amount of circulating ink in individual communication flow channels is increased to effectively expel air bubbles or foreign materials, then air bubble expulsion effectiveness is improved, but ejection energy efficiency is reduced resulting in reduced ejection rate or reduced ink droplet amount
Solution Approach 1:
The patent applies local quality by differentiating the flow channel resistance characteristics between common flow channels and individual communication flow channels. Specifically, the common flow channel is designed with a larger resistance (Rc) relative to the combined resistance of individual communication flow channels (Rt), creating a resistance ratio Rc/Rt ≥ 0.1. This local resistance differentiation ensures that ink circulation preferentially flows through individual channels during circulation mode, effectively expelling air bubbles from pressure chambers while maintaining proper ejection performance when nozzles are activated
2Manufacturing precision
If a high-density array of nozzles is implemented to reduce head size and enhance resolution, then head size is reduced and resolution is enhanced, but significant variance in flow amount of circulating ink among individual communication flow channels occurs
Solution Approach 1:
The patent implements equipotentiality by designing the flow channel resistance relationships to create balanced flow distribution across all nozzles. The resistance ratio conditions (Rc/Rt ≥ 0.1 and Ri/Rt ≤ 0.05 for each individual channel) ensure that all nozzles in the high-density array receive comparable ink circulation flow. This equalizes the hydraulic potential across parallel flow paths, preventing significant variance in circulating ink flow amounts among individual channels even in high-density nozzle configurations, thereby maintaining uniform ejection performance across all nozzles
3Use of energy by moving object
If the flow channel resistance of common flow channel is increased to reduce ink circulation flow, then ejection energy efficiency is improved, but air bubble expulsion effectiveness is reduced
Solution Approach 1:
The patent applies parameter changes by establishing specific resistance ratio thresholds that optimize the balance between air bubble expulsion and ejection efficiency. The common flow channel resistance Rc is set to satisfy Rc/Rt ≥ 0.1, while individual channel resistances Ri satisfy Ri/Rt ≤ 0.05. These parameter specifications create an optimal resistance distribution that allows sufficient circulation flow for effective air bubble removal while preventing excessive flow that would compromise ejection energy efficiency. The resistance parameters are carefully tuned to achieve both objectives simultaneously
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
The configuration effectively expels air bubbles and foreign materials while reducing variance in ink ejection performance among nozzles, maintaining ejection stability and efficiency.
Implementation Method 1
a damper which is provided so as to face an inner surface of the common flow channel and changes a volume of the flow channel by elastic deformation under pressure
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
The present invention addresses the problem of providing an ink-jet recording apparatus that is capable of effectively removing bubbles, foreign objects, and the like present inside a head, together with ink, while maintaining ink ejection stability. An ink-jet recording apparatus 200 according to the present invention is provided with such as an ink-jet head 100 having: individual connection flow channels 18 through which ink can be discharged from pressure chambers 13A; and a common flow channel 19 at which ink from the individual connection flow channels 18 merges, wherein when the ink is ejected, in a nozzle 11a through which the maximum amount of ink per unit time is ejected, the relationship of (Fn/Fi)≤10 is satisfied, Fn representing the amount of ink ejected per unit time from the nozzle 11a, and Fi representing the average flow rate of ink discharged per unit time from the individual connection flow channels 18, and the relationship of (Rc/Rt)≤10 is satisfied, Rc representing the flow channel resistance of the common flow channel 19, and Rt representing the synthetic resistance of the individual connection flow channels 18.