Segmented Rotary Screen Squeegee for Uniform Print Pressure

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Solution Overview

Problem

Existing screen printing machines with cylindrical cylinder molds and squeegees face issues with non-uniform squeegee pressure distribution, leading to premature wear and defects, as the pressure is high on the outside and low in the middle, requiring adjustments that either increase pressure at the edges or compromise the cylinder mold.

Innovation Solution

The squeegee is divided into individual, adjustable short squeegees that can be set to maintain consistent pressure across the cylinder mold width, with each squeegee's distance from the mold being adjustable, allowing for precise mechanical loading and improved service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the squeegee pressure is adjusted using only two screws on the left and right sides of the machine, then the squeegee pressure is increased at the outer edges of the rotary screen, but the squeegee pressure remains low in the center of the rotary screen

Engineering Contradiction:
Improvesqueegee pressure at outer edgesVSAvoidprint quality uniformity
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The squeegee is divided into multiple individually adjustable sections (at least three sections: left, center, and right), each with its own adjustment mechanism. This segmentation allows independent control of pressure at different locations, enabling high pressure at edges while maintaining appropriate pressure in the center, thus resolving the contradiction between edge pressure and print quality uniformity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each squeegee section is equipped with local adjustment capabilities through individual screws or adjustment mechanisms positioned at specific locations (left side screw, right side screw, and center adjustment). This enables localized pressure optimization where each section can be tuned to provide the exact pressure needed for its specific position on the rotary screen, achieving both high edge pressure and uniform center pressure

Inventive Principle:
Principle #3Local quality

2Stress or pressure

If the squeegee is adjusted further from the outside to increase pressure in the center of the rotary screen, then the squeegee pressure in the center is increased, but the pressure at the edges of the rotary screen increases excessively

Engineering Contradiction:
Improvesqueegee pressure in centerVSAvoidrotary screen durability
Core Design Contradiction:
Stress or pressureVSStrength

Solution Approach 1:

By dividing the squeegee into independently adjustable sections, the system allows the center section to be adjusted without affecting edge sections. The center section can be moved closer to increase pressure where needed, while edge sections maintain their original positions, preventing excessive edge pressure and protecting the rotary screen from premature wear

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Local adjustment mechanisms at each squeegee section enable independent pressure control. The center section can be locally optimized for pressure without transmitting excessive force to the edges, thus improving center print quality while preserving rotary screen strength and durability

Inventive Principle:
Principle #3Local quality

3Device complexity

If a single squeegee covers the entire printing area, then the structure is simple, but the squeegee pressure cannot be adjusted uniformly across the entire width of the rotary screen

Engineering Contradiction:
Improvesqueegee structure simplicityVSAvoidsqueegee pressure adjustability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The squeegee is segmented into multiple adjustable sections while maintaining a relatively simple overall structure. Each section has its own adjustment screw or mechanism, but the basic design remains straightforward. This segmentation provides adaptability for uniform pressure adjustment across the entire rotary screen width without significantly increasing structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each squeegee section incorporates local adjustment capabilities through simple mechanisms like adjustment screws positioned at strategic locations. This allows the system to maintain simplicity while gaining the versatility to adjust pressure uniformly across the entire printing width, adapting to different printing requirements

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3569416B1Squeegee for screen printing
Publication Date: 2021.07.07 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3569416B1 patent drawingFigure 1~2
  • EP3569416B1 patent drawingFigure 3~4

AI summary

The invention relates to a screen printing machine with a cylindrical rotary screen and a squeegee arranged in the rotary screen. According to the invention, the squeegee is divided into several individual short squeegees, each covering only a specific squeegee or print width to be printed, and its distance from the inside of the rotary screen transverse to the direction of rotation of the rotary screen is individually adjustable. This allows the distance of each individual short squeegee from the rotary screen to be set differently depending on its specific arrangement within the rotary screen, so that, in particular, the same squeegee pressure can be applied in the center of the rotary screen as at the outer ends, without subjecting the areas at the outer ends of the rotary screen to excessive squeegee pressure.