Liquid Recirculation Control for Printhead Particle Settling

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Solution Overview

Problem

Existing printer technologies face productivity losses due to the inability to maintain equal suspension of dispersed particles in printheads during printing mode, leading to potential clogging and reduced image quality, as liquid circulation can only be performed in maintenance mode and not during active printing.

Innovation Solution

A method involving an intermediate liquid reservoir and multiple liquid handling systems with controlled valves allows for dynamic regulation of liquid recirculation, prioritizing agitation in printheads with higher or lower liquid consumption, and adjusting circulation times based on consumption patterns to prevent settling during both printing and maintenance modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid circulation is performed through all printheads simultaneously using a single liquid handling system, then liquid agitation is achieved to prevent particle settling, but productivity is reduced because circulation can only be performed in maintenance mode

Engineering Contradiction:
Improveliquid suspension stabilityVSAvoidprinting productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The single liquid handling system is divided into multiple independent liquid handling systems (first liquid handling system, second liquid handling system, etc.), each capable of independently circulating liquid through its associated printhead. This segmentation allows selective circulation in specific printheads during printing mode, preventing particle settling without requiring complete system shutdown and maintaining productivity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If liquid circulation is performed in printing mode through printheads with different liquid consumption, then productivity is maintained, but unequal agitation occurs causing particle settling in printheads with lower liquid consumption

Engineering Contradiction:
Improveprinting productivityVSAvoidliquid suspension stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The circulation parameters for each liquid handling system are made dynamic and adjustable based on real-time printing conditions. The controller can independently regulate the circulation speed, flow rate, and duration for each printhead, allowing adaptation to varying liquid consumption patterns. This ensures adequate agitation in all printheads regardless of their current liquid usage, maintaining suspension stability while operating in printing mode.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Each liquid handling system is equipped with independent control capabilities, allowing localized adjustment of circulation parameters according to the specific needs of each printhead. Printheads with lower liquid consumption can receive enhanced circulation attention, while those with higher consumption require less intervention, optimizing agitation effectiveness across the entire system.

Inventive Principle:
Principle #3Local quality

3Reliability

If maintenance frequency is increased to ensure adequate agitation in all printheads, then particle settling is prevented, but productivity is reduced due to more frequent maintenance interruptions

Engineering Contradiction:
Improveparticle suspension stabilityVSAvoidprinting productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system enables continuous or near-continuous liquid circulation in each printhead by operating multiple liquid handling systems in parallel during printing mode. Instead of periodic maintenance interruptions, the circulation action continues continuously alongside printing operations, ensuring constant particle agitation and suspension stability without sacrificing productivity.

Inventive Principle:
Principle #20Continuity of useful 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 approach ensures continuous agitation of dispersed particles in all printheads, reducing maintenance frequency and maintaining image quality by allowing liquid recirculation during printing, thus minimizing productivity losses and preventing particle settling.

Implementation Method 1

a means for recirculating a liquid to the intermediate liquid reservoir... activate the means for recirculating a liquid to start recirculation of the liquid from the printhead in the first liquid handling system back to the intermediate liquid reservoir

Methodology Applied
Scientific EffectLiquid circulation: Pump

Implementation Method 2

a valve to regulate the recirculation... opening the valve to regulate the recirculation in the first liquid handling system; closing the valve to regulate the recirculation in the at least one second liquid handling system

Methodology Applied
Scientific EffectValve regulation: Valve

Data Source

PatentEP3219495B1A method for circulation of a liquid in a printer
Publication Date: 2020.08.05 CANON PRODN PRINTING HLDG BV
  • EP3219495B1 patent drawingFigure 1

AI summary

The present invention relates to a method for circulating a liquid in a printer to prevent settling of dispersed particles in the liquid anywhere in said printer by controlling the recirculation of liquid for each printhead in said printer.