Rotogravure Printing Unit Electrostatic Charge Neutralization
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Solution Overview
Problem
Rotogravure printing technologies fail to effectively neutralize ink polarization and electrostatic charges on printed materials, leading to issues like electrostatic attraction, adhesions, and reduced product quality.
Innovation Solution
A rotogravure printing unit equipped with an electrostatic printing aid apparatus that applies a first electrical polarity to the pressure roller and an anti-static bar at the outlet to neutralize residual charges, ensuring the printed material is free of electrostatic charges and ink polarization before drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an electrostatic printing aid apparatus is used to polarize ink and improve print quality, then ink coverage and print detail are improved, but residual electrostatic charges and ink polarization remain on the printed material causing electrostatic attraction and adhesions
Solution Approach 1:
The patent applies a second electrostatic charge of opposite polarity to neutralize the residual charges and polarized ink. By intentionally applying a controlled opposite charge, the harmful residual electrostatic effects are converted into a beneficial neutralization process, eliminating electrostatic attraction and adhesions while preserving the print quality improvements
Solution Approach 2:
The patent introduces a neutralization electrostatic charge as an intermediary element between the printing process and the final printed product. This intermediary charge acts as a mediator that cancels out the residual electrostatic effects without directly interfering with the ink transfer and polarization that create high-quality prints
2Object-generated harmful factors
If anti-static bars with alternating polarity are used to neutralize charges, then surface charges are removed, but ink polarization remains unaffected
Solution Approach 1:
The patent applies different electrostatic treatments to different aspects of the printed material. The first electrostatic charge specifically targets ink polarization for print quality, while the second opposite charge specifically targets residual surface charges for neutralization. This localized quality approach ensures each electrostatic application serves its specific function without interfering with the other
3Manufacturing precision
If the pressure roller is electrostatically charged to facilitate ink transfer, then ink coverage is improved, but residual charges are transferred to the printed material
Solution Approach 1:
The patent converts the harmful transfer of residual electrostatic charge to the printed material into a beneficial process by immediately applying an opposite polarity charge. This neutralization transforms the problem of charge transfer into a solution where the residual charges are deliberately cancelled out, preserving ink coverage while eliminating harmful electrostatic effects
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 neutralizes residual ink polarization and electrostatic charges, improving print quality by preventing electrostatic attraction and adhesions, resulting in a high-quality printed product.
Implementation Method 1
The electrostatic printing aid apparatus, associated with the pressure roller and having the function of distributing an electrostatic charge on the pressure roller outer sleeve lateral surface
Implementation Method 2
The presence of such surface charge has the purpose of generating an electric field between the pressure roller and the printing roller, through the sheet or roll material to be printed, interposed therebetween
Implementation Method 3
Such electric field helps to polarize the ink contained in the grooves, or cells, of the printing roller, to attract it against the sheet or roll material to be printed
Implementation Method 4
an anti-static bar at the outlet to neutralize residual charges
Data Source
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AI summary
A printing unit (1) for the rotogravure printing of a sheet or roll material (74), comprising: a printing roller (20), defining a printing roller rotation axis (22) and an outer printing roller lateral surface (21); a pressure roller (10) comprising a pressure roller body (11) and a pressure roller sleeve (30) which is fitted, or fittable, onto said pressure roller body (11), said pressure roller body (11) defining a pressure roller rotation axis (12) and a pressure roller body lateral surface (13); said pressure roller sleeve (30) having a tubular shape defining an outer sleeve lateral surface (31) and an inner sleeve lateral surface (33), said pressure roller sleeve (30) comprising an outer layer (32) made of elastomeric material delimited by said outer sleeve lateral surface (31); pressing means (60) for pressing said pressure roller (10) against said printing roller (20), so that a rotation of said pressure roller (10) and of said printing roller (20) is capable of feeding the sheet or roll material (74) interposed between said outer printing roller lateral surface (21) and said outer sleeve lateral surface (31) according to a feeding direction (73) of the material (74); an electrostatic printing aid apparatus (50) associated with said pressure roller (10) and configured to transmit electrostatic charges having a first electrical polarity to said outer lateral surface (31) of said sleeve (30); an electrostatic bar (110) arranged at the outlet with respect to said pressure roller (10) according to said feeding direction (73) of the material (74), and adapted to face said material (74), wherein said electrostatic bar (110) is configured to transmit electrostatic charges having a second electrical polarity opposite to the first electrical polarity to said material (74), so as to neutralize residual electric charges having the first electrical polarity, which remained associated with said material (74) downstream of said pressure roller (10).