Transcript Electro Static Solutions

Static Charge Solutions
Presentation by: 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


Charged surfaces will attract or repel other
charged surfaces.
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



Static charges can build up to high levels.
An electrostatic discharge can result.
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
 Friction
 Separation
 Induction
Copyright © 2002 Electro Static
Technology
Triboelectric Effect
Tribo means rubbing.
 Electrons are stripped away by moving
materials over stationary surfaces.
 Higher rubbing pressure increases the
effect.
 Faster speeds increase the resulting
electrostatic charges.

Copyright © 2002 Electro Static
Technology
Triboelectric series







Glass
Nylon
Aluminum
Paper
Rubber
PVC
Teflon

Positive Charge (+)

Negative Charge (-)
Copyright © 2002 Electro Static
Technology
Separation




Separation of materials (like and unlike) will
create static charges.
Paper passing through rubber or plastic
rollers will acquire static charge.
Paper passing through ungrounded metal
rollers will charge both paper and rollers.
Grounded conductive rollers will charge
paper during separation (roller charge will
flow to ground).
Copyright © 2002 Electro Static
Technology
Induction
When a charged surface is placed near
a conductive material, the charges in
the conductive material will separate.
 Grounded rollers will hold a charge
when near charged surfaces.
 Isolated conductive rollers will
experience charge separation when in
the vicinity of charged surfaces.

Copyright © 2002 Electro Static
Technology
Factors effecting static charge





Low relative humidity will amplify static
charge problems.
Lighter grades of paper will be affected
differently than heavier grades.
Coated paper will behave differently than
uncoated paper.
Mylar sheets are worst case.
Plastic frames and ungrounded metal
components augment static problems.
Copyright © 2002 Electro Static
Technology
Static Control Solutions
 Design
to reduce static generation.
 Install Static Control Devices.
Copyright © 2002 Electro Static
Technology
Design




Avoid sliding materials over surfaces as much
as possible.
Use textured or ribbed surfaces to reduce
contact area.
Simplify paper path through machine to
minimize contact with rollers.
Use light pressures to move media though
equipment.
Copyright © 2002 Electro Static
Technology
Static Control Devices




Static Control Devices use conductive fibers
placed near charged material to induce
ionization.
The correct polarity of ions required to
remove the static charge are produced at
the fiber tips.
No power supply is required.
Most cost effective method to remove static
charges from insulated material.
Copyright © 2002 Electro Static
Technology
Ionization

A charged surface will produce an electric
field perpendicular to the surface.
+++++++++++++++++
Copyright © 2002 Electro Static
Technology
Ionization

A sharp point placed near the field will
concentrate the field lines at the point.
+++++++++++++++++
Copyright © 2002 Electro Static
Technology
Ionization

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

The ions created by the corona discharge
will follow the electric field lines to the
charged surface and reduce the charge.
Charged
Surface
Copyright © 2002 Electro Static
Technology
Static Control Devices
Copyright © 2002 Electro Static
Technology
Static Control Device Construction
 Rigid
- Two Aluminum Strips bonded
together with fiber between strips.
Copyright © 2002 Electro Static
Technology
Rigid Static Control Device
A
F
G
H
B
C
D
E
Copyright © 2002 Electro Static
Technology
Static Control Device Construction
 Flexible
- Single Aluminum or
Conductive Film Strip with fibers
embedded into adhesive backing.
Copyright © 2002 Electro Static
Technology
Flexible Static Control Device
A
B
C
D
E TYPICAL
Copyright © 2002 Electro Static
Technology
Static Control Device Construction
 Fiber
–Carbon Fiber
–Stainless Steel Fiber
–Conductive Acrylic Fiber
Copyright © 2002 Electro Static
Technology
Carbon Fiber
Most effective in reducing static charge.
 Filament diameter is 7 μ-inch.
 1000 to 3000 filaments per fiber
bundle.
 Should be installed to minimize shear
forces when in contact with media.

Copyright © 2002 Electro Static
Technology
Stainless Steel Fiber
Very effective in removing static charge.
 Filament diameter is 12 - 14 μm.
 90 to 275 filaments per fiber bundle.
 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
Effective in removing static charge.
 Filament diameter is 15 - 19 μm.
 10 to 90 filaments per fiber bundle.
 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




Conductive fiber tips should be located 2 to 7 mm
from charged substrate.
Conductive fibers should not touch substrate to
ensure long life.
A 5 mm clearance between the fiber tips and
machine surfaces will ensure optimal static control.
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


Provide 5 mm of clearance around fiber tips.
Provide air space beneath paper.
Paper
Air Gap
Clearance
Copyright © 2002 Electro Static
Technology
Mounting

Static Control Device can be mounted at any angle
up to 90 degrees from charged surface.
Copyright © 2002 Electro Static
Technology
General Schematic for Static Control Device Location
3 *
2
1
2
1
3 *
Glass plate
Document Path
SCANNER
ADF
2
Document Tray
3
1
Imaging Drum
2
SORTER
Paper Path
Output Trays
2
IMAGER
Input Tray
FUSER
1
Improper Location - charge suppressed
2
Proper Location
3
Best Location - beyond last point of charge generation
Copyright © 2002 Electro Static
* Offset Static Control Devices if used on opposing sidesTechnology
for additional static control
Electro Static Technology
31 Winterbrook Road
Mechanic Falls, Maine 04256
Phone (207) 998-5140
Fax (207) 998-5143
E-mail [email protected]
Copyright 2001 Electro Static Technology
All Rights Reserved
Additional Static Control Device Locations in Machines
TRANSFER BELT
ISOLATED CONDUCTIVE ROLLER
Conductive roller which is isolated by nylon
bearings can be grounded through a Static
Control Device in contact with the shaft
Transfer Belt static charge can be reduced by
Static Control Devices installed along the full
width of the transfer belt and rollers as shown
PAPER SENSOR
INSULATED ROLLER
The presence of paper in a machine
can be detected by a Static Control
Device used as a soft contact sensor
Electro Static Technology
31 Winterbrook Road
Mechanic Falls, Maine 04256
Phone (207) 998-5140
Fax (207) 998-5143
E-mail [email protected]
Insulated roller static charge can be reduced
through a Static Control Device installed
along the full length of the roller
Copyright © 2002 Electro Static
Technology
Copyright 2001 Electro Static Technology
All Rights Reserved
Summary




Static charges are created by friction,
separation, and induction.
Static charges cause many problems in
paper transport equipment.
Electrostatic discharge can damage
electronics and hardware.
Proper location of Static Control Devices is
critical for effective charge reduction.
Copyright © 2002 Electro Static
Technology
Contact Information




For the best in passive static solutions contact
us today!
Immediate assistance for design, application,
samples, or pricing is just a phone call, email
or fax away.
Would an on-site technical presentation be
helpful? Contact us and lets discuss it.
Direct personal assistance from both our USA
and Far East sales departments.
Copyright © 2002 Electro Static
Technology
USA Contact Information




Address: Electro Static Technology
31 Winterbrook Road
Mechanic Falls, Maine 04256
Email: [email protected]
Phone: 207 998-5140
Fax:
207 998-5143
Copyright © 2002 Electro Static
Technology
Far East Contact Information




Address: Electro Static Technology, Japan
1-2-4 Minatojima-Nakamachi, Chuo-ku,
Kobe, 650-0046 Japan
Email: [email protected]
Phone: 81-78-303-6413
Fax:
81-78-303-4655
Copyright © 2002 Electro Static
Technology