Print Head Cleaning Nozzle for Continuous Inkjet Printers

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Solution Overview

Problem

Continuous ink jet printers face issues with dirt deposition inside the print head cavity, requiring manual cleaning that disrupts operation and is inefficient, and the formation of jets for cleaning often results in solvent wastage.

Innovation Solution

A method for cleaning the print head involves using a spraying nozzle to project cleaning fluid into the cavity, which can be rotated to target different areas, including the nozzle and gutter, with a system for evacuating the fluid and an accelerometer to optimize cleaning sequences based on the print head's orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual cleaning of the cavity is performed, then the dirt is removed from the print head, but the printing process is interrupted and time is lost

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidprinting interruption
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The print head performs its own cleaning automatically during operation. A cleaning jet system is integrated into the print head, allowing it to clean its own cavity without external manual intervention. The system uses a cleaning fluid delivered through a nozzle that can be directed at the cavity walls and components, enabling self-maintenance while the printing process continues uninterrupted.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the print head is disassembled for manual cleaning, then access to the cavity is obtained, but the complexity of the cleaning process increases and risk of contamination arises

Engineering Contradiction:
Improvecleaning accessibilityVSAvoiddisassembly requirement
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The cleaning system is fully integrated within the print head assembly, eliminating the need for disassembly. The cleaning nozzle and fluid delivery system are built-in components that allow the cavity to be cleaned from the inside without removing any parts. This maintains operational simplicity while providing effective cleaning access.

Inventive Principle:
Principle #25Self-service

3Reliability

If cleaning solvent is projected outside the cavity, then the cleaning effect is enhanced, but solvent wastage increases

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

Solution Approach 1:

The cleaning function is extracted as a separate, controlled process within the print head. Instead of projecting solvent externally, the system uses an integrated cleaning nozzle that delivers cleaning fluid precisely where needed inside the cavity. The solvent is contained and recirculated through the system, preventing wastage while maintaining effective cleaning of the cavity surfaces and components.

Inventive Principle:
Principle #2Taking out (Extraction)

4Extent of automation

If automated cleaning system is integrated into the print head, then manual intervention is reduced, but the device complexity increases

Engineering Contradiction:
Improvecleaning automationVSAvoidprint head structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The cleaning system is designed as a multi-functional integrated unit within the print head. The same structural components serve both printing and cleaning functions. The cleaning nozzle shares the fluid delivery infrastructure with the printing nozzles, and the control system manages both printing operations and cleaning cycles through a unified interface. This approach provides automation without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 method reduces the need for manual intervention, minimizes solvent wastage, and ensures effective cleaning of the print head without disturbing the printing process, maintaining efficiency and reducing downtime.

Implementation Method 1

at least one spraying nozzle, arranged in said cavity, said at least one spraying nozzle being different from said means for producing at least one ink jet

Methodology Applied
Scientific EffectFluid spray: Fluid Spray

Implementation Method 2

with this method comprising the projecting of a cleaning fluid towards the inside of the cavity, according to a piece of information relative to the orientation of the print head given by the accelerometer

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Data Source

PatentEP3932676B1Method and device for maintaining a nozzle print head
Publication Date: 2024.11.20 DOVER EUROPE SARL
  • EP3932676B1 patent drawingFigure 1~2
  • EP3932676B1 patent drawingFigure 3A~3B
  • EP3932676B1 patent drawingFigure 4A~4C

AI summary

The invention relates to a method for cleaning a print head of a continuous inkjet printer, said print head comprising: * a cavity (5) for the circulation of jets, * means (4, 41, 4x, 4n) for producing at least one ink jet in said cavity (5), - means (6), for sorting drops or segments of one or several of said jets intended for printing from drops or segments that are not used for printing; * at least one spraying nozzle (20, 24), arranged in said cavity, * an outlet slot (17), open onto the exterior of the cavity (5) and allowing the exiting of the drops or segment of ink intended for printing, * at least one gutter for recovering (7, 70) drops or segments not intended for printing, said method comprising: - supplying said spraying nozzle (20, 24) with cleaning fluid -and projecting several pulses of a cleaning fluid by said spraying nozzle into the cavity and towards at least: *the means (4, 41, 4x, 4n) for producing at least one ink jet in said cavity (5); *and/or the gutter for recovering; * and/or said means (6) for sorting drops or segments.