Static Charge Solutions Presentation by: Electro Static Technology

Copyright © 2002 Electro Static Technology Introduction Electrostatic charges can create problems in equipment which transport paper or other non-conductive media. This presentation will cover the basics of static charge generation. Cost effective solutions to reduce static charges to acceptable levels will also be explored in this session.

Copyright © 2002 Electro Static Technology Static Charge Problems n Charged surfaces will attract or repel other charged surfaces. n Charged surfaces in machines will cause: –Paper Jams –Double Sheet Feed –Uneven Paper Movement –Floating Paper Stacks –Contamination Problems

Copyright © 2002 Electro Static Technology Static Discharge Problems n Static charges can build up to high levels. n An electrostatic discharge can result. n The effects of electrostatic discharges: –Electric shock to personnel (mild to severe) –Permanent damage to circuit components –Damage to interface displays (LED, LCD) –Damage to print heads –Control system crashes (computer lockup) –Hardware failures (bearing erosion)

Copyright © 2002 Electro Static Technology Static Charge Generation n Friction n Separation n Induction

Copyright © 2002 Electro Static Technology Triboelectric Effect n Tribo means rubbing. n Electrons are stripped away by moving materials over stationary surfaces. n Higher rubbing pressure increases the effect. n Faster speeds increase the resulting electrostatic charges.

Copyright © 2002 Electro Static Technology Triboelectric series n Glass n Nylon n Aluminum n Paper n Rubber n PVC n Teflon n Positive Charge (+) n Negative Charge (-)

Copyright © 2002 Electro Static Technology Separation n Separation of materials (like and unlike) will create static charges. n Paper passing through rubber or plastic rollers will acquire static charge. n Paper passing through ungrounded metal rollers will charge both paper and rollers. n Grounded conductive rollers will charge paper during separation (roller charge will flow to ground).

Copyright © 2002 Electro Static Technology Induction n When a charged surface is placed near a conductive material, the charges in the conductive material will separate. n Grounded rollers will hold a charge when near charged surfaces. n Isolated conductive rollers will experience charge separation when in the vicinity of charged surfaces.

Copyright © 2002 Electro Static Technology Factors effecting static charge n Low relative humidity will amplify static charge problems. n Lighter grades of paper will be affected differently than heavier grades. n Coated paper will behave differently than uncoated paper. n Mylar sheets are worst case. n Plastic frames and ungrounded metal components augment static problems.

Copyright © 2002 Electro Static Technology Static Control Solutions n Design to reduce static generation. n Install Static Control Devices.

Copyright © 2002 Electro Static Technology Design n Avoid sliding materials over surfaces as much as possible. n Use textured or ribbed surfaces to reduce contact area. n Simplify paper path through machine to minimize contact with rollers. n Use light pressures to move media though equipment.

Copyright © 2002 Electro Static Technology Static Control Devices n Static Control Devices use conductive fibers placed near charged material to induce ionization. n The correct polarity of ions required to remove the static charge are produced at the fiber tips. n No power supply is required. n Most cost effective method to remove static charges from insulated material.

Copyright © 2002 Electro Static Technology Ionization n A charged surface will produce an electric field perpendicular to the surface.

Copyright © 2002 Electro Static TechnologyIonization n A sharp point placed near the field will concentrate the field lines at the point.

Copyright © 2002 Electro Static TechnologyIonization n The air molecules near the point will ionize if the electric field gradient exceeds the breakdown strength of air (3000 volts/millimeter).

Copyright © 2002 Electro Static Technology Corona Discharge n The ions created by the corona discharge will follow the electric field lines to the charged surface and reduce the charge.

Copyright © 2002 Electro Static Technology Static Control Devices

Copyright © 2002 Electro Static Technology Static Control Device Construction n Rigid - Two Aluminum Strips bonded together with fiber between strips.

Copyright © 2002 Electro Static Technology Rigid Static Control Device

Copyright © 2002 Electro Static Technology Static Control Device Construction n Flexible - Single Aluminum or Conductive Film Strip with fibers embedded into adhesive backing.

Copyright © 2002 Electro Static Technology Flexible Static Control Device

Copyright © 2002 Electro Static Technology Static Control Device Construction n Fiber –Carbon Fiber –Stainless Steel Fiber –Conductive Acrylic Fiber

Copyright © 2002 Electro Static Technology Carbon Fiber n Most effective in reducing static charge. n Filament diameter is 7 μ-inch. n 1000 to 3000 filaments per fiber bundle. n Should be installed to minimize shear forces when in contact with media.

Copyright © 2002 Electro Static Technology Stainless Steel Fiber n Very effective in removing static charge. n Filament diameter is μm. n 90 to 275 filaments per fiber bundle. n Resilient material - will withstand shear and abrasion, but may take on a “set” when bending contact with media is excessive.

Copyright © 2002 Electro Static Technology Conductive Acrylic Fiber n Effective in removing static charge. n Filament diameter is μm. n 10 to 90 filaments per fiber bundle. n Resilient material - excellent for use when moderate shear and bending forces are expected from contact with media.

Copyright © 2002 Electro Static Technology Static Control Device Location n Conductive fiber tips should be located 2 to 7 mm from charged substrate. n Conductive fibers should not touch substrate to ensure long life. n A 5 mm clearance between the fiber tips and machine surfaces will ensure optimal static control. n Static Control Device must be grounded. A ground wire connection will be necessary if device is mounted on an insulated surface.

Copyright © 2002 Electro Static Technology Clearance n Provide 5 mm of clearance around fiber tips. n Provide air space beneath paper.

Copyright © 2002 Electro Static Technology Mounting n Static Control Device can be mounted at any angle up to 90 degrees from charged surface.

Copyright © 2002 Electro Static Technology

Summary n Static charges are created by friction, separation, and induction. n Static charges cause many problems in paper transport equipment. n Electrostatic discharge can damage electronics and hardware. n Proper location of Static Control Devices is critical for effective charge reduction.

Copyright © 2002 Electro Static Technology Contact Information n For the best in passive static solutions contact us today! n Immediate assistance for design, application, samples, or pricing is just a phone call, or fax away. n Would an on-site technical presentation be helpful? Contact us and lets discuss it. n Direct personal assistance from both our USA and Far East sales departments.

Copyright © 2002 Electro Static Technology USA Contact Information n Address: Electro Static Technology 31 Winterbrook Road Mechanic Falls, Maine n n Phone: n Fax:

Copyright © 2002 Electro Static Technology Far East Contact Information n Address: Electro Static Technology, Japan Minatojima-Nakamachi, Chuo-ku, Kobe, Japan n n Phone: n Fax: