Sheet Processing Machine Deionization for Electrostatic Sheet Guidance
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Solution Overview
Problem
Existing sheet-processing machines, particularly in high-speed operations, face issues with electrostatic charging of sheets leading to attraction to guide plates, smearing, and unstable sheet guidance in turning areas, which are not effectively addressed by current deionization methods.
Innovation Solution
The implementation of discharge electrodes integrated into arc guide elements, such as arc guide plates, with optimal electrode spacing and pneumatic assistance, ensures effective deionization of sheets post-detachment from guide cylinders, maintaining sheet guidance without mechanical contact and preventing smearing or scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If deionization bars are arranged upstream of printing cylinders to neutralize sheets, then electrostatic charging is reduced, but the device complexity increases and adhesion of sheets to cylinders increases
Solution Approach 1:
The patent extracts the deionization function from complex multi-bar arrangements and concentrates it into a single comb-shaped electrode element positioned in the turning area. This simplified structure maintains deionization effectiveness while reducing device complexity and avoiding sheet adhesion issues associated with multiple upstream bars.
Solution Approach 2:
The invention positions the deionization electrode in the turning area (a different spatial dimension/timing) rather than upstream before printing. This timing change allows effective charge neutralization after sheets have been printed, avoiding the adhesion problems caused by upstream deionization while maintaining simplicity.
2Reliability
If discharge device is arranged in the rim area close to printing cylinder, then sheet guidance is improved, but the effectiveness is reduced and the rim is subject to increased wear
Solution Approach 1:
The patent moves the discharge device from the rim area to the turning area, a different spatial position and operational phase. This repositioning maintains sheet guidance reliability while avoiding the wear and effectiveness reduction associated with rim placement near printing cylinders.
Solution Approach 2:
The comb-shaped electrode acts as an intermediary element that provides discharge functionality without direct contact with sheets. Its teeth create controlled discharge zones that neutralize charges while preventing mechanical wear and maintaining effectiveness, unlike direct rim contact arrangements.
3Productivity
If sheets are conveyed at high speeds, then productivity is improved, but electrostatic charging increases causing attraction to guide plates and smearing
Solution Approach 1:
The patent applies deionization in the turning area as a preliminary action before sheets enter the printing zone. This timing ensures that electrostatic charges accumulated during high-speed conveyance are neutralized before printing, preventing attraction to guide plates and smearing while maintaining high productivity.
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 enhances sheet guidance in turning units, particularly for low-grammage and foil sheets, ensuring smooth conveyance through printing zones without waves or creases, improving machine performance and reducing surface damage.
Implementation Method 1
at least one discharge electrode (12) for discharging an arc
Implementation Method 2
pneumatic guide for the sheet
Data Source
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AI summary
The invention relates to a sheet-processing machine (1) with sheet-processing units, wherein the machine (1) includes at least two printing units (2) for processing sheets, wherein the printing units (2) each include a rubber cylinder (6) and a plate cylinder, and a rubber cylinder (6) of a printing unit (2) interacts with a sheet guide cylinder (5), wherein a sheet conveying system (7) is provided between two sheet guide cylinders (5), wherein the sheets are conveyed along a sheet conveying path by the sheet guide cylinders (5) and the sheet conveying systems (7) of the machine (1), wherein a sheet guide element starting in the area of the sheet guide cylinder (5) is provided below and along the sheet conveying path in one or all printing units (2) and/or a delivery unit (4).wherein a deionization device (8) is associated with the first section of the sheet guide element and wherein the machine (1) includes at least one unit designed as a primer unit. The invention also relates to a use of the sheet-processing machine (1) and a method for conveying sheets.