Print Head Cleaning Device with Segmented Pressure Element

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Solution Overview

Problem

Conventional cleaning methods for inkjet print heads risk pushing dirt into nozzles, leading to clogging, especially with inks containing large pigments, which can severely impact print quality, particularly in security document production.

Innovation Solution

A device with a cleaning head module featuring a replaceable pressure element having projections that fit into recesses on the print head, allowing for comprehensive cleaning of the underside and nozzles, with optional vibration and additional teeth for enhanced ink removal, ensuring optimal adaptation to different print head designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a pressure element is pressed against the print head to clean the surface, then cleaning effectiveness is improved, but dirt can be pushed into the nozzles causing clogging

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidnozzle clogging risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The pressure element is segmented with multiple projections distributed across its surface, each capable of engaging with recesses on the print head. This segmentation allows cleaning force to be distributed across multiple contact points, preventing concentration of force that could push dirt into nozzles while maintaining overall cleaning effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure element features projections with varying sizes, shapes, and distributions tailored to match specific recess patterns on different print head models. This local adaptation ensures that cleaning pressure is applied precisely where needed (at recess locations) while avoiding areas where dirt could be forced into nozzles.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a generic pressure element is used for cleaning, then device simplicity is maintained, but cleaning effectiveness is reduced due to inability to adapt to different print head designs

Engineering Contradiction:
Improvepressure element design simplicityVSAvoidcleaning effectiveness
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The pressure element is designed as a replaceable module that can be exchanged between different print head models. Each pressure element is optimized for a specific print head design, but the overall system achieves universality through modular replaceability, allowing the same cleaning device to service multiple print head configurations without redesigning the entire system.

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

Solution Approach 2:

The pressure element incorporates movable or flexible projections that can adapt their position and contact pressure dynamically during the cleaning process. This dynamic capability allows a single pressure element design to accommodate variations in recess patterns across different print head models, reducing the need for multiple specialized components.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If the pressure element is fixed in design, then manufacturing cost is reduced, but adaptability to different print head configurations is limited

Engineering Contradiction:
Improvepressure element manufacturing costVSAvoidadaptability to print head designs
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The pressure element is designed as a low-cost, replaceable component that can be manufactured using simple processes. Rather than investing in expensive, highly adaptable pressure elements, the system uses economical pressure elements that can be quickly replaced when worn or when changing print head models, reducing overall system cost while maintaining versatility.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

Pressure elements are pre-configured with projection patterns matched to specific print head recess patterns during manufacturing. This preliminary adaptation allows the pressure elements to be produced using standard, cost-effective processes while still achieving optimal cleaning performance for their designated print head models when deployed.

Inventive Principle:
Principle #10Preliminary 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

The solution provides a thorough and efficient cleaning process that effectively removes ink residues and dirt from the print head, preventing clogging and maintaining print quality, even with inks containing large pigments, and is adaptable to various print head designs.

Implementation Method 1

The friction of the projection on the recess surface additionally caused by the movement improves the cleaning result

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The projection can be designed as a vibration head, in particular as an ultrasound head, which generates vibrations, in particular in the ultrasonic frequency range

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP4368399A1Print head cleaning device, inkjet printer, and method for cleaning print head
Publication Date: 2024.05.15 BUNDESDRUCKEREI GMBH
  • EP4368399A1 patent drawingFigure 1
  • EP4368399A1 patent drawingFigure 2
  • EP4368399A1 patent drawingFigure 3

AI summary

The invention relates to a device (1) for cleaning a printhead (2) with a cleaning head module (4), wherein the cleaning head module (4) has a pressure element (3) and is adjustable between a cleaning position in which the pressure element is pressed against a printhead underside (22) of the printhead (2), and a release position in which the pressure element (3) is released from the printhead (2). The pressure element (3) has at least one projection (11) on the side facing the printhead underside (22), which, in a cleaning position, is received in a recess (19) formed on the printhead underside (22). The invention further relates to an inkjet printer and a method for cleaning a printhead.