Opto Power Corp. spells out history of Presstek's R/D laser technology. It should become quite clear who is the leader and pioneer in development of laser technology in the graphic arts industry. The new Presstek 4th generation laser is rumored to have now been bypassed by a new low cost, continuos wave laser, never before developed in any industry......and why not Presstek to bring another "holy grail" in laser technology to market. Thermal Laser Imagers, as we know them today, would not have been possible without Presstek's scientists and engineers developing the laser technology. And you ask why I am accumulating shares at these prices? Anyone hear of star wars? medical laser surgery, etc. etc?
High-Power Diode Lasers Make Strong Impression in Graphics and Medical Imaging Applications
by Tom Dearmin
Vice President, Sales
Opto Power Corporation
Suppose you're about to launch a new product but development of the brochure is running behind schedule. The deadline is tight because a big trade show is coming up in less than a week. You also have 10 reps demanding 500 brochures each. How can you quickly produce more than 5,000 full-color prints of your four-page brochure without sacrificing quality or spending more than your budget allows?
You know traditional offset printing is time consuming and complex, requiring significant make-ready time to convert digital files into film. And once a film is made, the images must be chemically etched into printing plates that are mounted on the cylinders of the printing press. Even if the printer agrees to meet your tight schedule, pre-press and setup costs can drive your budget beyond its limit. Therefore, you consider a quick-printer using a toner-based, short-run digital press, but now you face quality concerns.
A few years ago, this dilemma would have put you in a serious bind. Today, amid profound changes in the printing and publishing industries, you have two viable options: find an offset printer with an off-line computer-to-plate digital imaging system or on-line direct-to-press four-color printing press. Either of these filmless digital imaging solutions enable turnaround time as fast as 24 hours while cost effectively producing high-quality, offset lithographic printing in run lengths ranging from 400 to 50,000 pieces. Moreover, filmless digital imaging eliminates press registration problems that often occur with traditional printing methods.
As with other PostScript-based systems, proofing of direct-to-press and computer-to-plate technology can be handled seamlessly by a variety of digital proofing options, including the Iris ink jet and Imation Rainbow. Since there is no film involved, corrections can be made quickly and inexpensively. In addition, by eliminating the need for photosensitive materials, these digital imaging technologies don't produce environmentally hazardous waste by-products usually associated with traditional offset printing technology.
The evolution of filmless digital imaging in offset printing can be attributed to two primary forces: advances made in high-power diode lasers and the ingenuity of companies such as PRESSTEK, INC., a U.S. producer of digital imaging and printing plate technology. Beginning in the late 1980s, engineers at Hudson, N.H.-based Presstek began to consider high-power diodes as a replacement to spark discharge Technology, a difficult-to-control digital imaging technique that produced acceptable images but poor text quality.
By 1992, the price per watt of high-power diode lasers had fallen significantly, allowing Presstek engineers to employ them in these direct imaging applications. At the same time, technology and production advances made diodes available at higher output powers. In 1993, Presstek introduced its PEARLr imaging technology, the first digital imaging and printing plate technology incorporating high-power diode lasers as the imaging source in direct-to-press offset printing. The diodes enabled much higher resolutions -- over 2,000 dpi -- and more controllable placement of an imaging spot on the plate as compared to spark discharge technology.
Utilizing one-watt, CW, fiber-coupled, single-emitter diodes mufactured by Opto Power Corporation of Tucson, Ariz., Presstek's PEARL technology first appeared in direct-to-press (also called computer-to-press) kits the company produced for Heidelberger Druckmaschinen AG (Heidelberg, Germany), the world's largest printing press manufacturer. Initially incorporated in the Heidelberg GTO-DI, these digital imaging kits currently are in their third generation and feature as many as 64 diodes -- 16 per color. A similar kit now is being implemented in the four-color Heidelberg Quickmaster DI 46-4 as well.
Each kit Presstek supplies to Heidelberg consists of four PEARL diode-laser imaging units (one unit per color), the press computer, and all hardware and software needed to implement PEARL imaging on a Quickmaster DI 46-4. Another press manufacturer offering PEARL-based direct-to-press offset printing is Omni-Adast of Charlotte, N.C. The company recently introduced the OMNI-ADAST 705CDITM, the industry's first direct-to-press system offering large-format, four-up digital imaging.
The third-generation PEARL imaging technology also is used in Presstek's off-press PEARLsetterTM computer-to-plate system. Computer-to-plate technology is a cost-effective, off-line solution for offset print shops wishing to offer filmless digital imaging using their existing offset printing presses. The two architectures commonly used for imaging thermal materials off-press are internal or external drum machines. High-power diode lasers are used in external drum machines, with diode-pumped, solid-state lasers, such as those manufactured by Spectra-Physics Lasers of Mountain View, Calif., offering the preferred thermal source for internal drum machines. In addition to Presstek, other leading vendors of off-line thermal platesetters include CREO, Kodak, Agfa Graphic Systems, DuPont and Komori.
Implementing Opto Power's high-power diode lasers, Presstek produces aluminum-and polyester-based printing plates using an imaging technique called thermal ablation. This chemical-free approach removes the image-forming layers from the printing plate, thereby exposing the base layer of the plate that accepts the ink. During imaging, the diodes produce printer's dots by rapidly heating the image-forming layer.
The resulting thermal event causes the image and upper layers to break away, or ablate, from the plate. Once imaged, the plates are simply wiped down to remove the loosened top layer. At this point, they are ready to be mounted on the press.
Neil |
