Selective Solvent Injection for Inkjet Printer Circuit Cleaning

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Solution Overview

Problem

Continuous inkjet printers face blockages in ink circuits due to sedimentation of dense pigment particles, leading to difficulties in ink supply and increased solvent consumption during cleaning, which results in production downtime and higher costs.

Innovation Solution

A method and circuit design that allows selective solvent injection directly into the fluid recovery circuit without flowing through the print head or umbilical, enabling targeted cleaning and minimizing solvent usage by using multiple solvent supply channels and valves to control fluid flow, detecting blockages, and performing unblocking steps as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solvent is circulated through the entire ink circuit including print head and umbilical for cleaning, then comprehensive cleaning is achieved, but solvent consumption increases and cleaning time extends

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidsolvent consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The ink circuit is divided into segments (print head, umbilical, reservoir, channels) with selective solvent injection into specific segments. The patent injects solvent directly into the reservoir or specific channels rather than circulating through the entire circuit, segmenting the cleaning action to target only contaminated areas and reduce overall solvent usage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the ink circuit receive different treatments based on their contamination levels. The patent applies solvent cleaning locally to the reservoir and specific channels where pigment sedimentation occurs, rather than uniformly treating the entire circuit, optimizing the balance between cleaning effectiveness and solvent consumption.

Inventive Principle:
Principle #3Local quality

2Loss of substance

If solvent is injected directly into the reservoir or specific channels, then solvent consumption is reduced and cleaning time shortened, but cleaning coverage is limited

Engineering Contradiction:
Improvesolvent consumptionVSAvoidcleaning coverage
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The system performs preliminary detection of blockages using pressure sensors before initiating targeted solvent injection. By detecting contamination early and selectively injecting solvent only into affected channels or the reservoir, the system achieves effective cleaning with reduced solvent consumption without compromising overall cleaning coverage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ink circuit system performs self-diagnosis and self-cleaning through integrated pressure sensors and automated solvent injection. The system identifies blocked channels through pressure variations and autonomously initiates targeted cleaning, reducing the need for comprehensive manual cleaning cycles and minimizing solvent usage while maintaining effective cleaning coverage.

Inventive Principle:
Principle #25Self-service

3Reliability

If blockage detection and unblocking operations are performed, then printer reliability is improved, but production downtime increases

Engineering Contradiction:
Improveink circuit functionalityVSAvoidproduction downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system continuously monitors ink circuit pressure to detect blockages before they cause complete failure. By performing preliminary detection and initiating automated unblocking operations early, the system resolves issues during brief maintenance windows rather than requiring extended production downtime, thereby improving reliability while minimizing time loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ink circuit system autonomously detects blockages through pressure sensors and performs self-unblocking by injecting solvent into affected channels. This automated self-service capability resolves blockages quickly without requiring manual intervention or extended production shutdowns, balancing reliability improvement with minimal production downtime.

Inventive Principle:
Principle #25Self-service

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 improves cleaning efficiency, reduces solvent consumption, and allows for quicker printer restarts by ensuring clean solvent is used only where needed, thereby optimizing the cleaning process and minimizing downtime.

Implementation Method 1

a pump, supplied with solvent, to send the solvent to at least one of the means (50) that form part of the fluid circuit

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

a blocked situation of said means (50) is detected from at least one measurement of pressure variation during or after a start-up phase of said pump

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3093144B1Method and device for partial maintenance of a hydraulic circuit
Publication Date: 2019.09.11 DOVER EUROPE SARL
  • EP3093144B1 patent drawingFigure 1~2
  • EP3093144B1 patent drawingFigure 3
  • EP3093144B1 patent drawingFigure 4~5B

AI summary

The invention relates to a method of cleaning a fluid circuit in an inkjet printer that comprises a print head connected to the fluid circuit through an umbilical (19), and also comprises means (50) of recovering fluid from the print head (1), this method comprising at least sending solvent to said fluid recovery means (50), without making this solvent flow in the umbilical or in the print head.