Liquid Discharge Head Segmented Circulation for High-Viscosity Ink

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Solution Overview

Problem

High-viscosity liquid discharge apparatuses face challenges in achieving high-speed and stable discharge due to increased channel resistance, leading to defective discharge issues, and existing solutions either increase apparatus size or result in excessive backpressure.

Innovation Solution

A liquid discharge apparatus with a liquid discharge head featuring a common supply channel, recovery channel, and an adjustment channel with a valve that opens under a predetermined pressure, allowing liquid to flow through a lower resistance path, reducing channel resistance and backpressure during high-speed discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cross-sectional area of the channel is increased to reduce channel resistance, then liquid supply capability is improved, but the apparatus size increases

Engineering Contradiction:
Improveliquid supply capabilityVSAvoidapparatus size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The liquid circulation system is segmented into multiple independent channels (first circulation channel and second circulation channel) with different functions. The first channel provides liquid supply with sufficient flow rate, while the second channel provides backpressure regulation, allowing each channel to be optimized independently rather than requiring a single large channel

Inventive Principle:
Principle #1Segmentation

2Productivity

If the flow rate of liquid through the discharge unit is increased for higher speed discharge, then discharge speed is improved, but backpressure exceeds the appropriate range causing defective discharge

Engineering Contradiction:
Improvedischarge speedVSAvoiddischarge quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The circulation system is divided into two separate channels: the first circulation channel that supplies liquid at high flow rate for speed, and the second circulation channel that regulates backpressure for quality. This segmentation allows independent optimization of flow rate and backpressure without mutual interference

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second circulation channel acts as an intermediary mechanism that introduces controlled backpressure into the system. By regulating the flow rate through this channel, the system maintains appropriate backpressure levels even when the first channel operates at high flow rates for high-speed discharge

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If high-viscosity liquid is used to suppress permeation into the recording medium, then recording quality is improved, but channel resistance increases leading to insufficient liquid supply

Engineering Contradiction:
Improverecording qualityVSAvoidliquid supply capability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system uses two separate circulation channels to independently address the conflicting requirements: the first channel ensures sufficient liquid supply volume to overcome high viscosity effects, while the second channel maintains appropriate backpressure to prevent permeation, allowing high-viscosity liquid to be used effectively

Inventive Principle:
Principle #1Segmentation

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 suppression of defective discharge even at higher speeds by reducing pressure loss and maintaining appropriate backpressure, ensuring stable and high-quality liquid discharge.

Implementation Method 1

a valve (7) that opens under a predetermined pressure in the adjustment channel (6)

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3354467B1Liquid discharge apparatus and liquid discharge head
Publication Date: 2020.10.28 CANON KK
  • EP3354467B1 patent drawingFigure 1
  • EP3354467B1 patent drawingFigure 2A~2B
  • EP3354467B1 patent drawingFigure 3

AI summary

A common supply channel (4) is connected to one end of a discharge module having a discharge orifice (13) that discharges liquid, and a common recovery channel (5) is connected to the other end of the discharge module. A valve (7) connecting the common supply channel (4) and common recovery channel (5) is provided in an adjustment channel (6), and is opened under a first opening pressure. A pump causes liquid to flow from the common supply channel (4) toward the common recovery channel (5). Flow resistance of the common recovery channel (5) is smaller than flow resistance of the discharge module.