Appendix 1. Electrophotography: Building a Patent Portfolio in a Mature but Evolving Field

• Author: Donald S. Rimai
• Profession: Recently retired from Eastman Kodak where he worked as a researcher and intellectual property manager in digital printing and adhesion science
• Pages: 255-277

255

Background

e electrophotographic process, oen referred to as xerography, has been

extensively used in this book for exemplary purposes. To facilitate the

readers’ comprehension of this technology, it is worthwhile to give a brief

introduction. For more detailed descriptions of the equipment, materials,

and electrophotographic process, the reader is referred to several texts on

the subject [1–3].

e use of electrophotography as an exemplary technology for discussing

patents was not simply chosen because of the author’s background in this

area. Rather, it was chosen because, despite its existence for approximately

80 years, during which time printers and copiers using this technology

were developed and marketed by numerous companies, electrophotogra-

phy is still the subject of much development. As a result, it remains an area

of intense patent activity despite its being a mature eld comprising much

prior art. is appendix illustrates how it is possible to address problems

Appendix 1

Electrophotography: Building a

Patent Portfolio in a Mature but

Evolving Field

256 A Guide for Implementing a Patent Strategy

arising from an evolving technology that address previously unforeseen

applications, thereby producing many new patents.

First, unlike most technological advances, electrophotography arose

from the inventions of a single individual - Chester Carlson [4, 5]. His pat-

ents, awarded in 1940 and 1942, were led in 1938 and 1939, respectively.

His technology was uniquely disruptive in that it eventually led to the elim-

ination of alternatives such as the use of carbon paper, Verifax copiers*,

ditto masters, and mimeographic processes. However, at the time of his

invention, the future potential of electrophotography was not appreciated.†

Second, in the approximately 80 years since its invention, electrophotog-

raphy has morphed from the invention that nobody wanted into a multibil-

lion dollar per year international business encompassing many companies,

including Xerox, Eastman Kodak, Ricoh, Canon, Minolta, and many oth-

ers. In and by themselves, such ongoing activities for an extended period

such as have occurred in this eld would generate a multitude of patents,

as competing companies attempt to gain advantages over each other in the

marketplace. However, there is yet another reason for all the patent activity.

e use of this technology has evolved to meet new and exciting applica-

tions and opportunities that were unforeseen just a few years ago.

Originally, electrophotography was used primarily to reproduce docu-

ments. e quality of those reproductions was generally poor and the main

requirement was that the copy had to be readable. It was oen extremely

problematic to make a copy of a copy (oen referred to as “second genera-

tion” copies) because the image degradation was so extreme. Pictorial con-

tent was rare and, at the time, not really suitable for electrophotographic

reproduction. Moreover, as oce documents consisted mainly of black and

white text, the desire for processes that reproduced color was minimal. In

fact, up until the 1970s, zinc oxide (ZnO) was incorporated into the paper

receiver and served as the photoreceptor. ere was no separate photore-

ceptor or transfer subsystem. e use of the zinc oxide coated paper gave

rise to the displeasing feel of the copies.

* e Verifax process used silver halide technology to copy a document, which was then

transferred to an absorbent paper by pressing the developed silver halide print against the

receiving paper.

† e attempts made by Carlson to sell his technology to a multitude of established com-

panies such as IBM and Eastman Kodak is well documented. Aer repeated failures, Carl-

son attracted the interest of Joseph Wilson, CEO of a failing photographic paper company

named Haloid. Wilson bet his company on this new technology and changed its name to

Xerox, derived from the Greek and meaning “dry writing”.