Flat-Top Dots
Let’s start by stating what is meant by the term flat-top dot. A flat-top dot on a photopolymer plate is one that accepts the transfer of data from an imaging device to the finished plate at a 1:1 ratio. The 1:1 imaging ratio is measured in the file, post-CDI imaging, and ultimately on the final plate.
Now, let's dive into the details of what we have identified as the most frequent questions people ask about flat-top dots. We will release one question and answer over this 10-week timeframe.
Part 6. I have been told that all water-wash polymer plates are inherently flat-top; is this correct?
- The short answer is no. Not all water-wash polymers can be classified as flat-top plate materials.
- There are different methods used to create a flat-top plate, which include UV-LED exposure, lamination, introducing inert gases to the exposure, and plate technology that has the flat-top formulated into the raw material. Generally speaking, some water-wash technologies have been accepted to classify their polymer material as flat-top. What this comes down to is the degree of scrutiny that is placed on qualifying a plate as flat-top. Even within competing flat-top technologies, there is debate between manufacturers of whether or not a plate achieves a true 1:1 image reproduction ratio from the file to the finished plate. Again, most discrepancies would fall within the error of the measuring device. We have seen evidence of some water-wash material having a very slight sharpening effect. Still, We have not viewed any significant disadvantage to performance as it pertains to ink delivery or impression latitude.
- That said, to date, we do not know of a water-wash polymer that has been fully qualified with Esko's CDI and XPS Crystal technology expressly. XPS Crystal exposure is a newer technology that has taken screening to a new level. That is not at all to say that manufacturers of water-wash polymer will/are not aggressively working with Esko to their materials for XPS Crystal UV LED exposure. The Flenex FW plates use a rubber-based compound that limits the plate’s exposure to oxygen and resulting in the effect of flat-top dots. This gives a sharper dot shape and should mean that more ink is transferred to the substrate. Fujifilm says these plates are capable of producing a consistent 200 LPI at 4400 dpi, 1% flat top process dot structure. This particular plate is compatible with most flexo water-wash processors.
Check us out next week when we answer the question, “Aside from great ink laydown and SID, is there any other significant improvement to print quality that flat-top has to offer?"
If you want to learn more about this subject, please feel free to reach out to us by calling 1-800-445-4017, or by e-mail at [email protected].
All Printing Resources has formed our Technical Solutions Group (TSG) to encompass our full range of expertise in all critical areas of the flexo process. This team is made up of industry professionals dedicated to being up-to-date on new technologies along with best practices. They are armed with the latest in diagnostic tools and are experienced in problem-solving that can achieve sustainable results. The TSG has walked in your shoes, and have felt your pain.
Click here to read: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10.