Static electricity can destroy chips, but it may also lead to cheaper and smaller color printers. Lawrence Schein, a former IBM and Xerox
researcher, believes that electrostatic technology pioneered by Ben
Franklin over 200 years ago could be used to create color laser printers
that cost less and are up to 70% smaller than current models. "This is
the biggest innovation in laser printing in many years," he says.
Harnessing static electricity for text and image reproduction is hardly
new. It's already widely used in laser printers, photocopiers, and some
fax machines. But by taking a nanotechnology approach to static
charges, Schein and his research partner, Stanley Czarnecki of Torrey
Pines Research, have created an enhanced electrostatic process that
makes it possible to slash the amount of hardware that goes into a
color laser printer.
Electrostatic printing works by transferring charged toner particles
from a photoconductor belt to paper, where they are permanently fused
to the paper by heat. In a color laser printer, a second belt accumulates
and processes color images—black, cyan, magenta and yellow—one
hue at a time. The extra belt significantly increases the printer's size,
weight, and complexity.
Schein's goal was to decrease electrostatic adhesion. By making
toner particles less sticky, it would be possible to apply all color images
to a single photoconductor belt without disturbing already accumulated images. The approach promises color laser printers that aren't much
more complex or costly than current black-and-white models.
To diminish toner adhesion, Schein studied electrostatic attraction
theories and principles, including Gauss' law. He realized that the forces
that make plastic-based toner particles stick to surfaces during printing
are surprisingly strong. He eventually discovered that toner particles'
rough edges form very small contact footprints.
"That creates exceptionally strong attractive forces," Schein says.
To reduce the number of contact points, Schein completely coated
toner particles with 10-nm silica balls—a thousand times smaller than
the toner particle themselves. The silica nanoballs effectively smooth
the toner particles' edges and minimize the number of contact points.
"The result is reduced adhesion," Schein says. "The new system is
simply a roller with toner on it, spaced away from the photoconductor.
When the second color image comes around, the photoconductor's
electric field just pulls the toner across the gap and doesn't disturb a
previously developed color image."
Schein is currently consulting with Aetas Systems, a Taiwan-funded
startup that's dedicated to developing new laser printing technology.
Working with Schein, Aetas is developing a design for a new generation
of single-belt color laser printers that are comparable in weight and
complexity to today's black and white models.
