Literature & Support

Frequently Asked Questions

• Will static control devices work if not grounded?
  An ungrounded static control device will remove charge for a short period of time. Eventually the static control device will self charge and stop working when the electric field between the fiber tips and the charged surface is reduced to a level which cannot support ionization. Electro Static Technology recommends grounding static control devices to ensure proper operation.

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• What wire gauge is necessary for grounding a static control device?
  The ion currents are very low (microAmp range) therefore 22 gauge will be more than adequate. The ground wire gauge is usually specified for its mechanical strength rather than the current carrying capabilities.

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• What is the ideal fiber pitch in a static control device?
  Experimental data has shown that a 5mm pitch is ideal for a static control device. A tighter pitch does not increase the effectiveness while increasing the cost.

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• What should be the maximum gap in a static control device?
  The ions are very mobile and will easily travel 10mm from a fiber tip. Therefore, the gaps on the ends of the static control device can be 10mm and a gap inside the static control device should not exceed 20mm. Larger gaps will limit the effectiveness of the static control device.

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• What is the life expectancy of a static control device?
  A static control device will work for millions of cycles if the charged paper does not touch the fibers. Electro Static Technology recommends a distance of 2mm to 7mm between the fiber tips and the charged paper.

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• Will a static control device work if the fibers are in contact with the charged paper?
  Yes, but the life expectancy of the static control device will be reduced.

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• Will a static control device work if the fiber tips are greater than 7mm away from the charged paper?
  Yes, however, the effectiveness of the static control device will be reduced. A static control device will need a greater static charge to induce ionization when the distance of the fiber tips from the charged surface is increased.

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• Does a static control device remove all the charge from a charged surface?
  No, the electric field between the fiber tips and the charged surface will be reduced as the charge is reduced. At some point, the electric field will be reduced to a level that will not sustain ionization. All passive static control devices leave a residual charge. The objective of a static control device is to reduce the charge to a level that will not cause a paper process flow problem.

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• What degree of charge removal will eliminate problems in paper transport equipment?
  This has to be determined by testing the paper transport equipment in an environmental chamber with the relative humidity level below 15%. Variables such as paper composition, mechanical support of the paper through the equipment, and thickness of the paper will affect the results. The correct location of static control devices in the paper transport equipment will be determined by experiment.

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• Will grounded rollers and conductive plastics remove charge from paper?
  No, paper is an insulator and the paper will leave the grounded rollers and conductive plastic surfaces with a static charge due to charge separation. The static charges generated on the grounded rollers and conductive plastic surfaces will flow to ground, but the paper surface will remain charged. The only way to remove a static charge on an insulated surface is with a static control device.

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• Is the adhesive on the peel and stick static control device conductive?
  No, the adhesive is not conductive. Conductive adhesives are not very aggressive. The peel and stick static control device uses an aggressive adhesive with a space at the top and bottom of the holder to allow the fibers to make direct contact with a conductive surface under the static control device.

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• How can I measure the amount of static charge on a surface?
  Static charges are difficult to measure directly. An indirect method is to measure the surface voltage with an electrostatic field meter. The surface voltage can be measured before and after the installation of a static control device. The amount of voltage reduction is an indicator of the static control device effectiveness.

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• What is the best fiber material for my application?
  This depends on where the static control device is to be used. Carbon fiber is the most effective static reduction material. However, carbon fiber is a brittle material and will shed if the paper makes occasional contact with the fibers. We recommend carbon fiber at the exit trays of machines or anywhere that fiber shedding will not cause mechanical or electrical problems. Stainless steel should be used if the paper makes regular contact with the fibers of the static control device. Stainless steel is very resilient and will tolerate the abrasion of paper contact. Conductive acrylic should be used anywhere that fiber shedding cannot be tolerated. Conductive acrylic is the most robust fiber material and is often used inside paper transport equipment.

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• Why is carbon fiber the most effective material?
  Carbon fiber has the smallest diameter filaments of the common fibers used in static control devices. A small diameter filament concentrates the electric field and produces ionization at a lower static charge density than a larger diameter filament. Both stainless steel fiber and conductive acrylic fiber have larger diameter filaments than carbon fiber. However, stainless steel and conductive acrylic are still very good static reduction materials and are recommended anywhere that fiber shedding will cause mechanical or electrical problems inside machines.

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• Can static control devices remove static charges from materials other than paper?
  Yes, static control devices will reduce the charges on the surfaces of any insulated material. Static control devices are often used to reduce static charges from rubber rollers, plastic surfaces, and ungrounded conductive material.

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