CTP Flexo: A Bright Idea
Improved print quality is just one of the benefits driving the adoption of digital flexo plates.
March 2006 by Jean-Marie Hershey
|
Necessity is the mother of invention.” Plato gets credit for coining this phrase. While this is unquestionably true, it’s the forces of “necessity” that are relative. For example, necessity reared its head somewhat earlier in the offset world than in the world of flexographic package printing, where the migration from analog (film-based) to digital platemaking still lags the adoption of computer-to-plate (CTP) in other segments of the industry.
There are signs that this is poised to change. As consumer product companies and big box retailers look to drive sales through innovative, high-quality packaging—delivered faster and at lower cost than ever before—their printing providers are investing in flexo CTP to increase efficiency and cut waste. Despite estimates that only about 20 percent of packaging facilities worldwide currently use digital plate technology, the economic and creative advantages of CTP flexo are persuasive. Digital plates are said to promote better registration and dot reproduction, faster makereadies, more reliable process controls, and guaranteed repeatability that enables printers to react faster to customers’ needs.
CTP flexo: A primer
A flexographic digital plate consists of a photopolymer layer topped by a carbon-based masking layer. Flexographic CTP uses infrared lasers to ablate portions of the masking layer to uncover corresponding areas on the photopolymer layer.
Digital imaging of flexographic plates begins with placement of the plate material on an external drum or sleeve. As the imaging drum rotates, a laser head creates the image on the plate, creating a pattern of appropriately sized and spaced raised dots. This method, called “imaging in the round,” eliminates the distortion that can occur when, as in conventional flexographic platemaking, a flat plate is mounted to the printing cylinder after imaging. The process creates only minimal debris, which is removed by an extractor built into the system, followed by a water wash and a drying period.
Because CTP flexo eliminates film from the workflow, it also saves time, material, and labor incurred when working with and storing film negatives. Corrections can be made quickly and cleanly to the digital file, as opposed to producing new films for imaging. Finally, digital platemaking can eliminate the need to deal with unpleasant byproducts of computer-to-film (CTF).
According to Ian Hole, director, marketing development, Esko-Graphics, “There is little difference between preparing a final file for computer-to-film analog plate production and preparing one for processing via CTP flexo. While the settings will be different, you still have trapping, color, step-and-repeat, and other issues to consider. The need to image smaller dots also means that you have to consider how to treat highlights and shadows. Most important, CTP flexo has to consider different dot gain curves, as well as the choice of a screening technology.”
There are signs that this is poised to change. As consumer product companies and big box retailers look to drive sales through innovative, high-quality packaging—delivered faster and at lower cost than ever before—their printing providers are investing in flexo CTP to increase efficiency and cut waste. Despite estimates that only about 20 percent of packaging facilities worldwide currently use digital plate technology, the economic and creative advantages of CTP flexo are persuasive. Digital plates are said to promote better registration and dot reproduction, faster makereadies, more reliable process controls, and guaranteed repeatability that enables printers to react faster to customers’ needs.
CTP flexo: A primer
A flexographic digital plate consists of a photopolymer layer topped by a carbon-based masking layer. Flexographic CTP uses infrared lasers to ablate portions of the masking layer to uncover corresponding areas on the photopolymer layer.
Digital imaging of flexographic plates begins with placement of the plate material on an external drum or sleeve. As the imaging drum rotates, a laser head creates the image on the plate, creating a pattern of appropriately sized and spaced raised dots. This method, called “imaging in the round,” eliminates the distortion that can occur when, as in conventional flexographic platemaking, a flat plate is mounted to the printing cylinder after imaging. The process creates only minimal debris, which is removed by an extractor built into the system, followed by a water wash and a drying period.
Because CTP flexo eliminates film from the workflow, it also saves time, material, and labor incurred when working with and storing film negatives. Corrections can be made quickly and cleanly to the digital file, as opposed to producing new films for imaging. Finally, digital platemaking can eliminate the need to deal with unpleasant byproducts of computer-to-film (CTF).
According to Ian Hole, director, marketing development, Esko-Graphics, “There is little difference between preparing a final file for computer-to-film analog plate production and preparing one for processing via CTP flexo. While the settings will be different, you still have trapping, color, step-and-repeat, and other issues to consider. The need to image smaller dots also means that you have to consider how to treat highlights and shadows. Most important, CTP flexo has to consider different dot gain curves, as well as the choice of a screening technology.”
Companies Mentioned:
 |
|
Best Practices for Print Automation
Competing for Print’s Thriving Future
Diversifying with Packaging Services: Unlocking Hidden Profit Potential
Common-Sense Flexography
Chemistry for the Graphic Arts
What the Printer Should Know About Paper