Liquid Supply Device Circulation Path for Ink Viscosity Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Liquid discharge devices face instability in discharge performance due to increased viscosity of liquids at lower temperatures, which can lead to improper discharge from the liquid discharge head and unstable droplet formation.

Innovation Solution

A liquid supply device with a circulation path including a heater, filter, and bypass conduit is used to maintain stable ink temperature and prevent air bubbles from reaching the discharge head, ensuring consistent discharge performance by circulating ink through a system that includes a heater to control viscosity and a filter to capture air bubbles, while a bypass path directs air bubbles away from the discharge head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heater is provided on the circulation path to heat the liquid, then the liquid viscosity is adjusted for proper discharge, but air bubbles may be generated and affect discharge performance

Engineering Contradiction:

Improvedischarge performance stabilityVSAvoidair bubbles in liquid

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The circulation path is divided into separate segments: a heating section and a bubble removal section. The bubble removal section includes a bubble separation chamber that physically separates air bubbles from the liquid through gravity settling, allowing the liquid to be heated while preventing bubbles from reaching the discharge head.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A bypass conduit acts as an intermediary pathway that allows liquid to flow around the filter when bubbles are present. This bypass system prevents bubbles from entering the discharge head while maintaining continuous liquid circulation and heating.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a filter is provided to remove air bubbles, then discharge stability is improved, but the filter may become clogged and require maintenance

Engineering Contradiction:

Improvedischarge stabilityVSAvoidfilter maintenance requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically switches between normal filtration mode and bypass mode based on operational conditions. When bubbles are detected or during heating cycles, the bypass conduit becomes active, allowing liquid to circumvent the filter and preventing clogging while maintaining discharge stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The bubble separation chamber performs preliminary bubble removal before liquid reaches the filter. By separating large air bubbles in advance through gravity settling, the filter is protected from becoming clogged, reducing maintenance requirements while maintaining discharge stability.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If liquid is circulated through a heating element, then viscosity is controlled for stable discharge, but energy consumption increases

Engineering Contradiction:

Improveviscosity controlVSAvoidheating energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The heating element operates periodically rather than continuously. The controller activates heating only when liquid viscosity drops below a threshold or when discharge instability is detected, reducing energy consumption while maintaining reliable viscosity control through feedback-based periodic heating cycles.

Inventive Principle:

Principle #19Periodic 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 configuration stabilizes liquid discharge performance by maintaining optimal ink viscosity and preventing air bubbles from affecting the discharge head, resulting in consistent and efficient inkjet printing without the need for purge processing, which conserves ink and improves operational efficiency.

Implementation Method 1

a heater is provided in a liquid discharge device on the circulation path of the liquid discharge head on a primary side (e.g., upstream side) in order to heat the liquid to adjust the viscosity of a liquid

Methodology Applied

Scientific EffectViscosity adjustment through heating: Heating

Implementation Method 2

a filter to capture air bubbles

Methodology Applied

Scientific EffectAir bubble capture: Filter (physical)

Implementation Method 3

a bypass path directs air bubbles away from the discharge head

Methodology Applied

Scientific EffectBuoyancy-driven bubble separation: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11673401B2Liquid supply device and liquid discharge device

Publication Date: 2023.06.13 RISO TECH CORP

AI summary

A liquid supply device includes a first conduit, a second conduit, one or more pumps, a heater, a filter, and a bypass conduit. The first conduit is connected to an upstream side of a liquid discharge head. The second conduit is connected to a downstream side of the liquid discharge head. The liquid is supplied through the first conduit to the liquid discharge head and recovered from the liquid discharge head through the second conduit. The heater is provided along the first conduit. The filter is provided in the first conduit on a downstream side of the heater. The bypass conduit is connected between a portion of the first conduit upstream with respect to the filter and a portion of the second conduit.