Inkjet Printing Device Liquid Level Control During Purging

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Solution Overview

Problem

Inkjet printing devices face delays in starting printing after purging due to the need to adjust the liquid level in the pressure tank, which is reduced during ink circulation, leading to inefficiencies and potential clogging issues.

Innovation Solution

An inkjet printing device with a controller that maintains the liquid levels in both the pressure and negative pressure tanks at reference levels during purging through controlled ink feeding and replenishing operations, preventing the need for post-purge level adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If purging is performed by supplying ink from the pressure tank to the inkjet head, then thickened ink and foreign substances are discharged from the nozzle, but the liquid level in the pressure tank largely reduces

Engineering Contradiction:

Improvenozzle ejection reliabilityVSAvoidliquid level in pressure tank

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The controller performs liquid level maintenance operations during the purging process. Specifically, when the liquid level in the pressure tank falls below a reference level, the controller operates the ink pump to supply ink from the negative pressure tank to the pressure tank, and operates the ink replenisher to supply ink from the ink cartridge to the negative pressure tank. This preliminary action ensures the liquid level is maintained at the reference level throughout purging, preventing the need for post-purge adjustments and eliminating printing delays.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the liquid level is adjusted after purging to return to the state before purging, then the pressure tank is ready for printing, but a time delay occurs in starting printing

Engineering Contradiction:

Improveprinting readinessVSAvoidtime delay in starting printing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The liquid level maintenance operations are performed during the purging process itself, before printing needs to resume. The controller continuously monitors the liquid level and activates the ink pump and ink replenisher as needed to maintain the reference level throughout purging. This eliminates the need for separate post-purge liquid level adjustment, thereby preventing time delay in starting printing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The purging process is extended to include liquid level maintenance operations, making the entire process continuous and purposeful. Instead of completing purging and then separately adjusting liquid levels, the system integrates both functions into one continuous operation, ensuring the pressure tank is always ready for immediate printing without interruption or delay.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If ink is supplied from the pressure tank to the inkjet head during purging, then the nozzle is cleared of thickened ink, but the liquid level in the negative pressure tank may also be affected

Engineering Contradiction:

Improvenozzle clearanceVSAvoidliquid level in negative pressure tank

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The controller monitors the liquid level in the negative pressure tank and adjusts the ink pump operation accordingly. When the liquid level in the negative pressure tank falls below a reference level, the controller operates the ink pump to supply ink from the negative pressure tank to the pressure tank. This feedback mechanism ensures the liquid level in the negative pressure tank is maintained at the reference level throughout purging, preventing depletion and ensuring continuous availability of ink.

Inventive Principle:

Principle #23Feedback

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 solution ensures immediate readiness for printing after purging by maintaining optimal liquid levels, preventing delays and clogging, and effectively managing ink circulation and pressure settings.

Implementation Method 1

a circulation path for circulating ink among the first tank, the inkjet head, and the second tank

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

an ink replenisher that replenishes ink in the second tank

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS9498971B2Inkjet printing device

Publication Date: 2016.11.22 RISO KAGAKU CORP

AI summary

A controller controls an ink liquid feeding operation performed by an ink pump from a negative pressure tank to a pressure tank, and an ink replenishing operation performed by an ink replenisher according to a liquid level in each of the pressure tank and the negative pressure tank so that, during purging, the liquid level in each of the pressure tank and the negative pressure tank is maintained at a reference level.