Screen Printing Cylinder Radius and Speed Control

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Solution Overview

Problem

Existing sheet-fed printing units configured as screen printing units face challenges in maintaining stability and precision due to differences in circumferential speeds and radii between the screen printing forme cylinder and the impression cylinder, leading to potential instability and damage to the cylindrical screen.

Innovation Solution

A sheet-fed printing unit with a screen printing forme cylinder and an impression cylinder, where the impression cylinder has a supporting surface with a constant barrel radius extending over 170° and a screen printing forme cylinder with an effective screen radius smaller than the barrel radius, ensuring stability and precision by maintaining identical angular velocities and circumferential speeds during printing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the screen printing forme cylinder and impression cylinder have different radii and circumferential speeds, then the printing unit can accommodate different design requirements, but the cylindrical screen becomes unstable and may be damaged

Engineering Contradiction:

Improvedesign flexibilityVSAvoidcylindrical screen stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the circumferential speed of the screen printing forme cylinder while maintaining a constant impression cylinder speed. During printing operations, the forme cylinder runs at a first circumferential speed matching the impression cylinder's surface speed. During adjustment operations, it transitions to a second circumferential speed that is lower, preventing excessive tension on the cylindrical screen while still allowing operational flexibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the forme cylinder's circumferential speed variable rather than fixed. The system dynamically switches between two operational states: a printing state with higher speed for productivity, and an adjustment state with lower speed for screen protection. This dynamic speed control resolves the contradiction between design flexibility and screen stability.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the screen printing forme cylinder runs at high speed continuously, then productivity increases, but the cylindrical screen experiences excessive tension and becomes unstable

Engineering Contradiction:

Improveprinting speedVSAvoidcylindrical screen stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies periodic action by implementing cyclic transitions between two speed regimes. The forme cylinder alternates between a first circumferential speed during printing operations and a second lower circumferential speed during adjustment operations. This periodic speed variation allows the system to achieve high productivity during printing while periodically reducing tension to maintain screen stability.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system changes the operational parameter of forme cylinder speed based on the operational phase. During printing, the speed is set to maximize productivity; during adjustment operations, the speed is reduced to protect the screen. This parameter change strategy resolves the contradiction between productivity and stability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the forme cylinder radius is increased, then the cylindrical screen becomes more stable, but the printing unit complexity and space requirements increase

Engineering Contradiction:

Improvecylindrical screen stabilityVSAvoidprinting unit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Rather than increasing the forme cylinder radius to improve screen stability, the patent changes the operational parameter of circumferential speed. By controlling the speed relationship between the forme cylinder and impression cylinder, the system achieves screen stability without modifying the physical dimensions or increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12103295B2Sheet-fed printing unit configured as a screen printing unit and methods for operating a sheet-fed printing unit configured as a screen printing unit

Publication Date: 2024.10.01 KOENIG & BAUER AG

AI summary

In some examples, a sheet-fed printing unit is configured as a screen printing unit and includes at least one screen printing forme cylinder and at least one impression cylinder cooperating therewith. A cylinder barrel of the impression cylinder includes a supporting surface for sheets, and which includes at least one impression portion having a constant barrel radius that extends over an angle of at least 170 degrees about the axis of rotation of the impression cylinder. The screen printing forme cylinder has an effective screen radius that is smaller than a barrel radius of the impression cylinder, and the effective screen radius is larger than half the barrel radius.