Inking Device Pressure Control for Flexographic Printers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flexographic printing machines experience uneven wetting of the anilox roller due to pulsing ink flow from pneumatic double-membrane pumps, leading to pressure variations within the inking chamber, resulting in non-optimal print quality and ink loss.
Innovation Solution
An inking device with control means that adjust the passage opening of outlets in response to pressure changes, using elastic elements like flexible lamina or ball elements to maintain constant pressure within the inking chamber, ensuring stable contact pressure between doctor blades and the anilox roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic double-membrane pumps are used to transfer ink, then safety in explosive environments is improved and the ability to suck ink from the inking chamber is achieved, but pulsing ink flow causes cyclic pressure variation in the inking chamber leading to uneven anilox roller wetting and print defects
Solution Approach 1:
A compensating chamber is introduced as an intermediary between the inking chamber and the pump system. This chamber absorbs the pulsing pressure variations by providing an expansion and contraction volume, thereby mediating the harmful pressure fluctuations before they reach the inking chamber and doctor blade system.
Solution Approach 2:
The system changes the pressure parameter dynamically by allowing it to vary in the compensating chamber while maintaining relative stability in the inking chamber. The compensating chamber acts as a pressure buffer, absorbing peaks and troughs in the pulsing pump output through volume expansion and contraction.
2Ease of operation
If the system for moving and supporting the inking device is not perfectly rigid, then ease of operation and absorption of mechanical stresses are improved, but movement during pressure cycles causes further variation in contact pressure between doctor blades and anilox roller
Solution Approach 1:
The compensating chamber serves as a mediator that decouples the flexible positioning system from the pressure-stable inking chamber. By absorbing pressure variations before they reach the inking device mounting system, it allows the positioning system to remain flexible without transmitting pressure-induced movements to the doctor blade contact point.
3Device complexity
If pressure variation in the inking chamber is allowed, then ease of manufacture and simplicity of structure are maintained, but uneven filling of anilox roller cells occurs resulting in ink loss and suboptimal print quality
Solution Approach 1:
The compensating chamber is a relatively simple additive component that introduces minimal structural complexity while effectively mediating pressure variations. It provides a passive pressure-buffering function without requiring complex active control systems, maintaining ease of manufacture while ensuring uniform cell filling.
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 effectively compensates for pressure variations, maintaining consistent ink distribution and preventing print defects, enhancing print quality and safety while simplifying construction and reducing costs.
Implementation Method 1
control means (13) adapted to vary, in at least one region, the passage opening (9a) of the outlets (9) as a function of the pressure of the ink inside the inking chamber (7). The control means comprise at least one flow control element (14) arranged at the respective outlet (9) and movable between a position for opening the corresponding outlet (9) and a position for at least partially closing the corresponding outlet (9)
Data Source
AI summary
An inking device for printing machines that comprises an inking body which is designed to be arranged so as to face the lateral surface of an anilox roller and forms an inking chamber that is open toward the anilox roller and has at least one inlet for introducing the ink into the inking chamber and at least one outlet for the exit of the ink from the inking chamber, and control elements that are adapted to vary the passage opening of the or of each outlet as a function of the pressure of the ink in the inking chamber.