Development of the world's first "Four-Drum Tandem Digital Color Laser Electrophotographic System."
Koji Hirakura, a Ricoh executive engineer of the Research and Development Group, and also the MFP Business Group, has won the Johann Gutenberg prize for the year 2010 from IS&T (Society for Imaging Science & Technology). The honor was bestowed on September 22 at the 26th International Conference on Advances in Non-Impact Printing Technologies, which was the major annual meeting of the society held in the U.S.
The Johann Gutenberg prize, has been given since 1987, is awarded to person world yearly. It is awarded to one or two persons who made a significant contribution in science and technology for the printing, and is presented by IS&T under sponsorship of Hewlett-Packard Laboratories.
Hirakura has consistently been engaged in research and development of electrophotography since he joined Ricoh in 1970. Development of the world’s first "Four-Drum Tandem Digital Color Laser Electrophotographic System," which Hirakura led from the middle of the 1980s, was highly evaluated and won him this award. This system has also been adopted by other companies for their color multifunction copiers, color laser printers, or for color production printing systems; it is firmly established as a standard printing technology.
|Mr. Koji Hirakura with President of IS&T, Dr. Rita Hofmann at the Award Presentation on IS&T NIP26/DF2010 (Austin,Texas).||The award plaque and engraved medal|
In the second half of the 1980s, many companies began developing a digital color copier for commercialization, using the electrophotographic system. The "one-drum four-cycle system" of those days required repeated imaging process by Cyan (C), Magenta (M), Yellow (Y), and Black (K) to reproduce a color copy; it took 4 times longer to create a copy compared with monochrome copying machines - it was very slow. The "four-drum tandem system" developed by Ricoh processes the four colors on four photoreceptor drums simultaneously to speed things up fourfold. The Ricoh ARTAGE 8000 digital color copy machine (released in 1990) adopted this engine and set the world’s fastest speed of 15 pages (A4) per minute for a color copy machine at the time. This technology was presented at the NIP7th annual conference of IS&T in 1991, and Ricoh’s high level of technical capabilities attracted world attention.
The "four-drum tandem system" achieved high-speed printing with four colors (CMYK), but it wasn’t easy. Looking back at that time, Hirakura says "It was obvious that printing speed would increase fourfold if four colors could be processed simultaneously. But there were many complex problems on how to harmonize the properties of each sub-system, such as electrostatic charging, photoreceptor, toner development and transfer, properties that fluctuate significantly even in monochrome systems. There were other issues as well, such as color registration of four-drum tandem system. Beyond that, downsizing of the device was also requested." Nevertheless, Ricoh challenged these challenging technical subjects. "The project tasked 60 to 70 engineers from various fields in the company, such as physics, chemistry, mechanical, electronic, optics ,laser and software, and they repeated straightforward arguments, development, prototypes and experiments every day. They overcame the problems one by one, also introducing varied electrophotographic process control technologies. There was much suffering, but I think the fact that we boldly challenged a difficult technology nobody had ever tried. Their challenge was evaluated and led to this award."
Although the demand for color copy machines was still limited at the time, Ricoh developed the digital color copy machine on the "four-drum tandem system" ahead of the industry, greatly contributing to accelerating the use and diffusion of high-speed digital color printing.
Hirakura also served as the president of The Imaging Society of Japan from April 2008 to March 2010.