Electrostatic Sheet Holding in Printing Press Transport
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Solution Overview
Problem
Existing sheet-fed printing machines face challenges in maintaining sheet alignment and preventing premature detachment during transport, leading to faulty prints due to centrifugal force and gravity, especially in sloping sections and during double-sided or multi-colored printing.
Innovation Solution
The use of electrostatic charging, facilitated by a high-voltage electrode, to charge the substrate sheet without physical contact, combined with blown air to support holding the sheet in place, particularly at critical points in the transport path between printing units, thereby preventing premature detachment and ensuring accurate printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrostatic charging is applied to hold sheets on the impression cylinder, then sheet adhesion is improved, but the complexity of the device increases due to additional electrodes and control systems
Solution Approach 1:
The patent replaces mechanical pressing forces with electrostatic forces to hold sheets on the impression cylinder. High-voltage electrodes generate electric fields that create adhesion without mechanical contact, eliminating the need for additional pressing mechanisms and reducing device complexity while improving sheet adhesion reliability
Solution Approach 2:
The patent changes the physical state of the sheet-impression cylinder interface by applying electrostatic charges. By controlling voltage parameters, the system adjusts adhesion strength dynamically, allowing reliable sheet holding with minimal mechanical intervention and simplified device structure
2Manufacturing precision
If centrifugal force and gravity are not suppressed during sheet transport, then the transport path can be simpler, but faulty prints occur due to sheet detachment and misalignment
Solution Approach 1:
The patent replaces mechanical constraints (complex transport path geometry, additional guiding mechanisms) with electrostatic fields to control sheet position. The electric fields suppress centrifugal and gravitational effects, maintaining printing accuracy without requiring complex mechanical transport structures
Solution Approach 2:
The patent applies electrostatic forces in advance during sheet transport to counteract centrifugal and gravitational effects before they cause detachment or misalignment. This preliminary anti-action prevents faulty prints by maintaining sheet stability throughout the transport path between printing units
3Reliability
If physical contact is used to hold sheets during transport, then the holding force is stronger, but the freshly printed surface may be damaged or contaminated
Solution Approach 1:
The patent substitutes mechanical contact-based holding with non-contact electrostatic holding. High-voltage electrodes create electric fields that grip the sheet without physical contact, providing strong holding force while completely avoiding damage or contamination of the freshly printed surface
Solution Approach 2:
The patent introduces an electric field as an intermediary between the holding mechanism and the sheet. This intermediary transfers holding force without direct contact, allowing reliable sheet retention while protecting the printed surface from mechanical damage and contamination
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 the risk of faulty prints by maintaining sheet alignment and preventing smearing or duplication of images, enhancing the reliability of the printing process, especially in scenarios with high centrifugal forces or sloping transport paths.
Implementation Method 1
a high-voltage electrode (37; 41) which, when electrical voltage is applied, can electrostatically charge a substrate sheet (02) being fed past it
Implementation Method 2
a blowing device (43; 44) directed towards the periphery of the rotating means of transport (33; 39; 38) upstream, which, when switched on, supports holding the sheet (02) in place with air forces
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a device for printing printing material sheets (02) with a first printing point (12) which is configured between a first cylinder (19; 19*) which acts as a transport cylinder (19; 19*) and a second cylinder (18), and at which the printing material sheets (02) can be printed on one or both sides with one or more compiled single colour printed images, and with a second printing point (11) which lies downstream in the printing material path, is arranged at a level which lies below the first printing point (12), is configured between a third cylinder (17) which acts as a transport cylinder (17) and a fourth cylinder (16), and at which the printing material sheets (02) can be printed on one or both sides with one or more compiled single colour printed images, wherein the printing material sheets (02) can be conveyed via at least one rotating transport means (33; 38; 39) along a transport path from that cylinder (19; 19*) of the first printing point (12) which acts as a transport cylinder (19; 19*) to that cylinder (17) of the second printing point (11) which acts as a transport cylinder (17), wherein at least one first electrode (37; 41) which is directed onto the circumference of the at least one rotating transport means (33) in an angular segment which lies in the transport path for the printing material sheets (02) is arranged on the transport path downstream of that cylinder (19; 19*) of the first printing point (12) which acts as a transport cylinder (19; 19*) and upstream of that cylinder (17) of the second printing point (11) which acts as a transport cylinder (17), in such a way that a printing sheet material (02) which is guided past the electrode (37; 41) can be charged electrostatically in the case of an applied electric voltage.