Flexographic Drum Cleaning via Oscillating Presser

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Solution Overview

Problem

Existing cleaning methods for flexographic printing machines require extensive machine downtime and substrate interruptions due to inefficient cleaning processes, particularly in removing dirt from the outer peripheral edges of rotating cylinders, which are time-consuming and costly, and involve frequent cloth replacements that necessitate substrate cuts.

Innovation Solution

A cleaning apparatus with a cross-piece and oscillator that allows for oscillating movement parallel to the rotational axis of the drum, enabling continuous cleaning without substrate cuts, using a presser and cleaning cloth with controlled fluid distribution to spread and remove dirt in a single revolution, and a system for seamless cloth replacement without interrupting the printing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a wide cleaning cloth and presser are used to clean the entire width of the drum, then the cleaning coverage is improved, but the cleaning time increases and machine downtime is extended

Engineering Contradiction:
Improvecleaning coverage areaVSAvoidmachine downtime
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The cleaning apparatus employs dynamic oscillating motion of the drum surface relative to the stationary cleaning cloth, replacing the traditional method of moving the entire cleaning unit. This allows the cleaning cloth to remain stationary while the drum oscillates back and forth, achieving complete cleaning coverage without requiring the cleaning unit to traverse the entire drum length, thereby significantly reducing cleaning time and machine downtime

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention transforms the cleaning approach from a one-dimensional linear traversal along the drum axis to a two-dimensional solution combining drum rotation with oscillating motion. The drum rotates to bring different circumferential areas into contact with the stationary cleaning cloth, while oscillating motion ensures complete width coverage, eliminating the need for the cleaning unit to move along the drum length

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the cleaning unit is moved to replace soiled cloth, then the cleaning effectiveness is maintained, but the substrate must be cut and re-attached causing production interruptions

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidprinting production continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention extracts the cleaning cloth from the moving cleaning unit and makes it a separate, stationary component. The cleaning cloth remains fixed in position while the drum oscillates to bring different surfaces into contact with it. This separation allows the cloth to be easily replaced without moving the entire cleaning unit, eliminating the need to interrupt substrate flow and cut/re-attach the substrate

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables self-service cloth replacement where the stationary cleaning cloth can be quickly exchanged without requiring movement of the cleaning unit or interruption of the printing process. The oscillating mechanism continues to operate with the new cloth, maintaining cleaning effectiveness while ensuring continuous substrate flow and production

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the cleaning unit moves parallel to the drum axis for cloth replacement, then the cloth can be changed, but the substrate flow is interrupted requiring cuts

Engineering Contradiction:
Improvecloth replacement operationVSAvoidsubstrate printing continuity
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The invention segments the cleaning system into stationary components (cleaning cloth, presser) and the moving component (oscillating drum). This segmentation allows the cleaning cloth to be independently replaced without moving the entire cleaning unit, enabling easy cloth change operations that do not interrupt substrate flow or require cutting and re-attaching the substrate

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

This solution significantly reduces cleaning time, minimizes machine downtime, and allows continuous printing by enabling efficient dirt removal and cloth replacement without interrupting the substrate flow, thus enhancing operational efficiency and reducing costs.

Implementation Method 1

The oscillator is configured to impart to each of the presser and the cleaning cloth during a cleaning phase of operation, oscillating movement of alternating strokes directed parallel to the rotational axis of the drum

Methodology Applied
Scientific EffectOscillation: Harmonic Oscillator

Implementation Method 2

A portion of cloth corresponding to the active surface of the presser is suitably moistened with cleaning fluids

Methodology Applied
Scientific EffectWet cleaning:

Data Source

PatentEP2502746B1Apparatus and method for rapid cleaning of a central drum of flexographic printing machines
Publication Date: 2014.12.24 ELETTRA
  • EP2502746B1 patent drawingFigure 1~2
  • EP2502746B1 patent drawingFigure 3~4
  • EP2502746B1 patent drawingFigure 5~6

AI summary

Apparatus and method for the rapid cleaning of the central drum (T) of flexographic printing machines includes a cleaning device (D) with presser (7,8), cloth (9) and fluid. The presser (7,8) brings the cloth (9) into contact with the rotating central drum (T). The presser (7,8) undergoes a suitable oscillating movement parallel to the axis (A) of the rotating central drum (T). At the ends of the cleaning device (D), the shoulders of the base of the flexographic machine are equipped with any suitable opposed openings (K) of the correct width through which the cleaning device can be inserted or removed axially so as to allow replacement of the cloth (9) without the need to cut the substrate (S).