Liquid Discharge Head Parallel Channel Circulation

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Solution Overview

Problem

Liquid discharge heads face issues with liquid thickening near discharge orifices due to evaporation, leading to changes in discharge speed and accuracy, particularly after long intermission periods, resulting in defective discharges that affect image quality.

Innovation Solution

A liquid discharge head design featuring first and second discharge orifice rows with corresponding pressure chambers, liquid supply and recovery channels, where the flow direction within pressure chambers is the same, facilitating circulation and preventing thickening by recovering and recirculating ink through parallel channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid is circulated through a single channel between the discharge orifices and heating resistance elements, then liquid thickening due to evaporation is suppressed, but defective discharge occurs after long intermission periods due to increased viscosity and solidification of components

Engineering Contradiction:

Improvedischarge reliabilityVSAvoiddischarge accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The liquid circulation system is segmented into multiple parallel channels (first liquid supply channel, first liquid recovery channel, second liquid supply channel, second liquid recovery channel) instead of using a single channel. This segmentation allows independent flow paths that maintain liquid fluidity more effectively, preventing viscosity increase and solidification during intermission periods, thereby ensuring reliable discharge after long idle periods.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the liquid circulation system are given different functions through the parallel channel configuration. The first and second liquid supply channels and recovery channels create localized flow patterns that ensure continuous liquid movement near discharge orifices, maintaining uniform liquid properties and preventing localized thickening or solidification that would affect discharge accuracy.

Inventive Principle:

Principle #3Local quality

2Speed

If liquid circulation is implemented to prevent evaporation and thickening, then discharge speed and landing accuracy improve during operation, but liquid may solidify near discharge orifices during intermission periods

Engineering Contradiction:

Improvedischarge speedVSAvoiddischarge reliability after intermission

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The parallel liquid supply and recovery channels enable continuous liquid circulation even during intermission periods when discharge operations are not active. This continuous flow prevents liquid from stagnating and solidifying near discharge orifices, maintaining discharge reliability after long idle periods while preserving the speed and accuracy improvements achieved during active operation.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The liquid circulation system performs preliminary action by continuously moving liquid through the parallel channels before intermission periods end, preventing viscosity increase and solidification from occurring. This proactive circulation maintains liquid readiness for immediate discharge after intermission, ensuring both operational speed and post-intermission reliability.

Inventive Principle:

Principle #10Preliminary action

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 design enhances discharge accuracy and quality by maintaining fluidity and preventing clogging, ensuring high-definition and high-quality image formation even after extended periods of inactivity.

Implementation Method 1

pressure chamber rows provided corresponding to the first and second discharge orifice rows, and having recording elements configured to generate energy used to discharge liquid

Methodology Applied

Scientific EffectThermal energy generation: Heating

Implementation Method 2

volatile components in the liquid discharged from the discharge orifices evaporate, and the liquid thickens near the discharge orifices

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10457062B2Liquid discharge head

Publication Date: 2019.10.29 CANON KK

AI summary

A liquid discharge head includes a recording element board including multiple discharge orifices configured to discharge liquid, multiple pressure chambers that communicate with the multiple discharge orifices via discharge channels, and have therein recording elements configured to generate energy used to discharge liquid, a liquid supply channel configured to supply liquid to the multiple pressure chambers, and a liquid recovery channel configured to recover liquid from, the multiple pressure chambers. The multiple pressure chambers communicate with the liquid supply channel and the liquid recovery channel so that liquid flows through the multiple pressure chambers. The direction of flow of liquid in the multiple pressure chambers is the same direction.