Droplet Discharge Head With Restricted Circulation Channels
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Solution Overview
Problem
Existing droplet discharge heads face issues with droplet discharge efficiency due to ink return from pressure generation chambers into supply and circulation channels, leading to a shortage of droplets discharged from nozzles.
Innovation Solution
The droplet discharge head incorporates a configuration with supply and circulation channels having small cross-section portions with smaller cross-sectional areas, which apply resistance to ink flow, preventing excessive ink return and maintaining optimal pressure for efficient droplet discharge. This includes a structure with laminated piezoelectric elements and specific channel resistances to control ink flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the circulation channel has a large cross-sectional area, then ink flow is smooth and pressure loss is reduced, but excessive ink returns from pressure generation chambers into supply and circulation channels causing droplet discharge deficiency
Solution Approach 1:
The circulation channel is designed with non-uniform cross-sectional area, featuring a small cross-section portion and a large cross-section portion. This local variation in geometry allows the channel to have different flow characteristics at different locations: the small cross-section portion restricts ink return while the large cross-section portion maintains smooth flow and reduces pressure loss.
2Quantity of substance
If the supply channel has a small cross-sectional area, then ink return from pressure generation chambers is restricted, but pressure loss increases and ink supply to nozzles becomes insufficient
Solution Approach 1:
The supply channel incorporates a small cross-section portion at a specific location to restrict ink return from pressure generation chambers, while including a large cross-section portion to maintain smooth ink supply flow and minimize pressure loss. This localized geometric variation allows the channel to perform multiple functions simultaneously.
3Reliability
If pressure generation chambers are isolated from circulation channels, then ink return is prevented, but residual pressure decay increases and droplet discharge consistency deteriorates
Solution Approach 1:
The circulation channel is designed with a small cross-section portion that creates controlled flow resistance. This allows some ink to return from pressure generation chambers to the circulation channel (preventing complete isolation), while the small cross-section restricts excessive return. The controlled interaction maintains pressure balance and reduces residual pressure decay, improving droplet discharge consistency.
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 enhances droplet discharge efficiency by preventing ink shortage and reducing residual pressure decay, allowing for a balanced shift between ink filling and discharge operations, thereby improving overall printing performance.
Implementation Method 1
a plurality of pressure generation chambers, to apply pressure to liquid in the plurality of pressure generation chambers
Data Source
AI summary
A droplet discharge head includes a plurality of discharge orifices, a plurality of pressure generation chambers, a supply liquid chamber, a plurality of supply channels, a circulation liquid chamber, and a plurality of circulation channels. The discharge orifices discharge droplets. The pressure generation chambers are communicated with the discharge orifices, to apply pressure to liquid in the pressure generation chambers. The supply liquid chamber stores liquid to be supplied to the pressure generation chambers. The supply channels are communicated with the pressure generation chambers. The circulation liquid chamber receives liquid collected from the pressure generation chambers. The circulation channels communicate the pressure generation chambers with the circulation liquid chamber. Each of the circulation channels includes a small cross-section portion that has a smaller cross-sectional area in a width direction perpendicular to a longitudinal direction of each of the circulation channels than another portion in the longitudinal direction.