Print Head Expansion Element and Filter for Clogging Prevention

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Solution Overview

Problem

Print heads used in industrial printing processes, particularly for semiconductor structures like photovoltaic solar cells, are prone to clogging due to debris and foreign particles, which impede the flow of print media and lead to precision issues and equipment failure.

Innovation Solution

A print head design featuring an expansion element to increase the flow cross-section aspect ratio, a detachable output unit with filters, and a pressure sensor to maintain consistent pressure, along with additional filters and a pre-filter to prevent particle clogging, ensures that the flow path remains clear and precise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the outlet openings have a small diameter to print fine lines, then the printing precision is improved, but the risk of clogging by particles increases

Engineering Contradiction:

Improveprinting precisionVSAvoidrisk of clogging

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A filter element is introduced as an intermediary component between the print medium inlet and the outlet openings. This filter captures particles in the print medium before they can reach and block the small-diameter outlet openings, thereby maintaining both the fine line printing capability and the reliability of the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The filter element performs preliminary action by removing particles from the print medium upstream of the outlet openings. This preliminary filtration prevents particles from reaching the vulnerable small-diameter openings, addressing the clogging risk before it can affect printing precision.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the flow cross section is increased to improve print medium flow, then the flow rate is improved, but the aspect ratio requirement creates structural constraints

Engineering Contradiction:

Improveflow rateVSAvoidaspect ratio

Core Design Contradiction:

ProductivityVSShape

Solution Approach 1:

The expansion element increases the flow cross-section by expanding in the lateral dimension perpendicular to the print medium flow direction. This creates a reservoir-like structure that enlarges the available flow area without extending the flow path length, thereby improving flow rate while meeting aspect ratio requirements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If the print head is assembled in a clean environment to prevent particle contamination, then the reliability is improved, but the ease of operation during maintenance is reduced

Engineering Contradiction:

Improveparticle contamination resistanceVSAvoidmaintenance ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The print head is segmented into modular components: a base unit and a detachable output unit. The filter element is integrated with the output unit, allowing the entire output unit to be removed and replaced as a single module. This segmentation enables maintenance personnel to perform filter replacement without requiring clean room conditions, as the filter is protected within the sealed output unit during handling.

Inventive Principle:

Principle #1Segmentation

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 design significantly reduces the risk of clogging, maintains precision in printed lines, and ensures consistent print quality by filtering out debris and maintaining optimal pressure, thereby extending the lifespan of the print head and improving operational reliability.

Implementation Method 1

an expansion element, which is arranged in the flow path of the print medium between the print medium inlet and the output openings in order to expand the flow cross section in the flow direction of the print medium to an aspect ratio of at least 3:1

Methodology Applied

Scientific EffectFluid expansion:

Implementation Method 2

an output filter for the print medium, wherein in the operating state with the output unit arranged on the base the output filter is arranged in the flow path of the print medium between the print medium inlet and the output openings

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3747655B1Push button and method for producing a push button

Publication Date: 2022.09.28 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

Figure 1a~1b
Figure 2
Figure 3

AI summary

The invention relates to a printhead for parallel extrusion of printing medium, in particular for the production of conductive traces, with a printing medium inlet for the printing medium, which is fluidly connected to a plurality of output openings of the printhead, for the simultaneous output of printing medium from the output openings and with an expansion element, which is arranged in the flow path of the printing medium between the printing medium inlet and the output openings, in order to expand the flow cross-section in the flow direction of the printing medium to an aspect ratio of at least 5:1.Essentially, the printhead comprises a base unit with the print medium inlet and the expansion element, and an output unit detachably arranged on the base unit. The output unit has a plurality of output openings and at least one output filter for the print medium, wherein, in the operating state with the output unit arranged on the base unit, the output filter is located in the flow path of the print medium between the print medium inlet and the output openings. The invention further relates to a method for manufacturing a printhead.