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  • Kodak "Thermal Direct" Plate

    HI All.
    Looking for feedback on the Kodak "Thermal Direct " plate. I have been told that the plate develops on the press within the first 20 sheets.
    That there is no contamination of the fountain solution, rollers or blankets. Which leaves me a bit confused. Normally the sheet size is smaller
    than the plate size, so where does all the emulsion from the difference in size go? Would be interested to hear from anyone useing this plate
    in a production enviroment.

  • #2
    Re: Kodak "Thermal Direct" Plate

    It would vary probably with your specific uses/run lengths etc. but a major printer in our area switched away from this plate because it was taking longer to clear on press than a plate that didn't require this. I heard yesterday that Kodak is recommending for some a processor water wash step first to avoid this. Just a tidbit for you to chew on, lots of variables go into making a specific decision in a certain plant though.

    I'd like to add that this was on their very fast web press, short runs.

    Edited by: Prepper on Sep 19, 2007 11:54 AM

    Comment


    • #3
      Re: Kodak "Thermal Direct" Plate

      Hi Prepper.
      Thanks for the reply. I would still like to know were the rest of the emulsion goes. If its not on the paper it has to go somewhere.

      Comment


      • #4
        Re: Kodak "Thermal Direct" Plate

        Hi Gaz,

        We looked at the Kodak "Thermal Direct" Plate system when doing research for our recent move to CTP metal plates.

        Our question to the Kodak reps was exactly the same as yours... the sheet size is always smaller than the plate, so where was this extra emulsion going. We were told that the whole plate inks up, the extra emulsion transfers from the plate, and you're left with the image ready to go within 10-20 press sheets. Sounded very messy. Anyway, they beat around the bush a bit, no straight answers, and our press operators were not keen on the idea at all...

        We were impressed with the platesetter specs and the Prinergy software looked nice, but the 'on-the-press' developing just wasn't going to be an option in our shop. We even mentioned to the Kodak reps the possibility of them adding a wash out unit prior to the plate going on the press, but they wouldn't budge, sticking strictly to their ideals of the Thermal Direct being a processless plate. Needless to say we didn't go with Kodak.

        I have also heard along the grapevine about press problems due to emulsion buildup off the plates, and as Prepper mentioned that Kodak might be leaning towards some sort of wash out unit, but again, just heresay so take it at face value only...

        Cheers, Tony

        Comment


        • #5
          Re: Kodak "Thermal Direct" Plate

          Hi Tony.
          Thanks for your input. My feelings are the same as yours. It all sounds to good to be true.
          Pays do ask around which is why this site is so good.
          Cheers
          Gaz.

          Comment


          • #6
            Re: Kodak "Thermal Direct" Plate

            Hi Gaz,
            as it happens, we tested the Thermal Direct plates yesterday. Here are some of my impressions.

            We have been promised some technical literature on exactly where the emulsion goes by our technical plate rep, but I haven't seen it yet. If it shows up in my inbox, I will pass along the official word.

            Don't think of this plate emulsion as a thick layer like any developed plate you have used. It is so thin it is almost not there. I would say it is an order of magnitude thinner than even film emulsion. If you wet down a corner of the plate, the emulsion comes off in a grey tinged liquid, no lumps or strings, not even any visible particles. Our feeling, among management and press operators, is that it would present no real problems if you are doing a couple of colour washes each day and changing fountain solution on a regular basis.

            Thats the end of the good news.

            The first problem we saw was the matter of the plates being light sensitive until they are processed on the press. Our plate bags do not cover the entire plate on our duplicators, we would need to switch to larger envelopes at a much greater expense, or come up with some other work-arounds to protect the plates from light.

            We found the image to be too hard to see to be useful in our shop. We are running a 20 year old Miller with a console, but no workflow input to set ink keys. Our pressman couldn't see the image well enough to set keys on the console the way he normally does. There are software solutions to this problem, but it looks to me like they would take dozens of jobs to get set up, if the pressman could be convinced to use "a bunch of numbers" instead of his eyes. Also, there is no way to do that "last check" of the job before mounting the plates.

            We tried the plates on the Miller TP-74 I just mentioned, an older ITEK 975 duplicator, and a Heidelberg QM-46. The only press that liked these plates was the Heidelberg. They plugged in on the Miller, and would not clean up without greatly increasing the water feed on the damps. On the ITEK, they needed a cleaning with plate cleaner before they ran clean. The Heidelberg however was up to colour and running clean within 5 sheets.

            In discussions with the Kodak sales rep, he admitted that the plates were more geared toward modern presses with ink key information coming from the workflow and newer dampening systems. He would not admit to any willingness to supply us with a wash-out/gumming system. Even if the plate were washed out, there is still very little contrast between the image and the background aluminum. I didn't try it, but I doubt you could use a densitometer to check platesetter calibration.

            It's really too bad, because I like the Creo workflow and equipment that Kodak has inherited. I just think that there is too much ego involved to admit that the plates should be washed and gummmed like the AGFA and Heidelberg chem free plates.

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            • #7
              Re: Kodak "Thermal Direct" Plate

              HI Pressgeek.
              Thanks a mil for your input. Would be interesting to see what the technical literature says if it turns up.
              Never really thought about the thickness of the emulsion so that does paint a less scary picture.
              Pity about all the other problems that comes with it. Just seems to be a lot of hassle to me. Pity.
              Cheers.
              Gaz.

              Comment


              • #8
                Re: Kodak "Thermal Direct" Plate

                We use Thermal Direct plates. Yes, they need to be kept in a dark location before going on press. (1 hour white light max, 4 hours yellow). After the unhardened emulsion is gone they can be treated like any other plate.

                No problems developing on press - our sheet size is smaller then the plate size.

                The one MAJOR problem is that they have a very short run length, we are getting 10,000 imp before the screens fade. The red is first to go followed by the others. This is after multiple calibrations by Kodak. Don't believe the numbers quoted by Kodak, the hardened emulsion is still fairly soft compared to traditional plates and does wear.


                We also have problems with Kodak not honoring their pricing contract with us, but that's another story.

                -Eric

                Edited by: Eric McMaster on Oct 1, 2007 1:39 PM

                Comment


                • #9
                  Re: Kodak "Thermal Direct" Plate

                  Hi Eric.
                  Thanks for adding that. Very interesting. How long have you been useing the plate? Any sign of the emulsion building up on the press?
                  Is the 10,00 imp your standard run length or do have to remake a set of plates? Just trying to get a handle on the costs and production times.
                  If you do remake the plates, is there any difference in colour between the plates or is it pretty much the same?
                  Quite a few questions but I would like to get a clear picture so I will look forward to your reply.
                  Cheers
                  Gaz.

                  Comment


                  • #10
                    Re: Kodak "Thermal Direct" Plate

                    Hi Gaz,

                    The answer requires a bit of explanation about how the develop-on-press mechanism of Thermal Direct plates works. To enable the develop-on-press mechanism to function without contaminating ink or fountain solution, Kodak’s research scientists engineered a proprietary molecular structure for the coating resins that enables the coating to be applied in an ultra-thin layer, yet retain sufficient durability and chemical resistance to deliver up to 100,000 impressions and excellent press chemical resistance (depending on press conditions).

                    The press start up procedure for Thermal Direct plates is a bit different than for a traditional processed plate. First, imaged plates are mounted on press, the press is started, and fountain solution is applied to the plate…ideally for at least 20 revolutions. With respect to the develop-on-press mechanism, the effect of the fountain solution is to dissolve the plate coating in non-image areas. Yet, even as the coating dissolves into the fountain solution, it retains its affinity for ink. After the plate is thoroughly covered with fountain solution, the ink forms are engaged…again ideally for at least 20 revolutions, and the dissolved coating is attracted to the ink. Finally, paper is fed into the press and the dissolved coating is transferred to the make ready sheets.

                    With respect to edges of the plate that are outside the area of the press sheet, Thermal Direct plates function just like any other litho plate. During roll up, ink and dissolved coating in these areas will be transferred to the blanket, and in the case of a single-sided press, to the impression cylinder; in the case of a blanket-to-blanket perfecting press, just to the blanket. This ink/coating combination remains on the blanket and/or impression cylinders until these cylinders are cleaned, either when the job is complete or at some point during the run in the case of longer runs.

                    This process is no different than that which takes place with a traditional, processed plate. That is, when ink is first applied to a traditional processed plate, it covers the entire surface of the plate, and is immediately transferred to the blanket with successive press revolutions. When paper feed is engaged, the blanket ink transfers to the sheet, except for ink on the blanket that is outside the area of the press sheet. Edges of the plate outside the area of the press sheet are kept ink free by the action of the fountain solution. But ink from initial roll up remains on the edges of blanket and impression cylinders until cleaned by the press operator.

                    In the case of the Thermal Direct plate develop-on-press mechanism, the ink on the edges of the blanket and impression cylinders—that is, the edges of the cylinders outside the area of the press sheet—will have a small component of dissolved and removed coating. Because of the ultra thin coating layer used for Thermal Direct plates, the amount of this coating is, quite literally, miniscule and has no effect on the operation of the press.

                    Comment


                    • #11
                      Re: Kodak "Thermal Direct" Plate

                      HI Pam.
                      Thanks for that gem. Just the type of information I am looking for. However, maybe as you work for Kodak you can shine some light on
                      a few of the points the others have raised in their replies, such as the water wash out option, image hard to see, can you check the contrast
                      with a densi and the really big one of run lengths of 10,000 when you claim 100,00. Look forward to your reply.
                      Cheers
                      Gaz.

                      Comment


                      • #12
                        Re: Kodak "Thermal Direct" Plate

                        Hi Gaz,

                        The Thermal Direct plate was designed as a develop-on-press plate, and as such, Kodak does not offer or recommend use of a standalone processing option.
                        As you are probably aware, develop-on-press technology is not a new idea. Over the years, several manufacturers, including Kodak, attempted to bring DOP plates to market. Though workable, the technology previously did not enjoy success, largely because the removed coating was found to contaminate the press: compromising ink colors, altering the wetting characteristics of fountain solutions, and changing ink flow and tack.

                        Throughout the development of the Thermal Direct plate, Kodak research scientists paid particular attention to these problems of DOP technology. Extensive research indicated that the cause of press contamination was twofold: 1) the high coating weights needed to provide acceptable run lengths could not be adequately dispersed by inks and founts and carried away by the press sheet; and 2) the coloring agents used to make the plate image highly visible contaminated inks and fountain solutions.

                        To address the first issue, Kodak’s synthetic chemists developed a unique coating resin with a proprietary molecular structure that enables the coating resin to be applied in a layer that is ultra thin, yet durable enough for run lengths of 100,000 impressions or more. Extensive testing has shown that dispersion of this very small amount of coating has no effect on either the wetting characteristics of the fountain solution or the viscosity and laydown properties of the ink.

                        While researching the second issue, Kodak chemists determined that the coloring agents traditionally added to coating resins to render a plate image highly visible were, when used in a develop-on-press environment, a major source of ink color contamination. Thus, the colorants added to the custom resin for Thermal Direct plates were reduced to the absolute minimum needed to create an image of sufficient visibility to permit identification of plates for press cylinder placement. Twelve-point type is readable for press placement, but the latent image on Thermal Direct plates does not have sufficient contrast for densitometer measurement. Given the inherent accuracy and repeatability of the CTP process in general, and thermal CTP in particular, most users of Thermal Direct plates have not found this to be an issue. However, this is not to say that Thermal Direct plates are appropriate for every application. Kodak offers several other more traditional plates that permit densitometer measurement and have other characteristics that may be better suited for the specific requirements of a job.

                        Regarding the run length question, the answer is that the run length any particular user can achieve is highly dependent on press conditions. Kodak arrived at the 100,000 impression run length specification for Thermal Direct plates after extensive testing in a wide variety of press conditions. We are aware that some Thermal Direct plate users have experienced challenges reaching 100,000 impressions. Conversely, we are also aware of Thermal Direct plate users who regularly achieve run lengths of 300,000 impressions and beyond. This is not a situation unique to Thermal Direct plates. It is common to see this sort of run length range with a traditional processed plate. This is not a fault of the plate or the user, but rather a result of the wide variation in press conditions seen in the worldwide printing industry. Again, Kodak’s position is that Thermal Direct plates are not for use by every user in every application. Like all Kodak’s other plate products, the features and functions of Thermal Direct plates must be appropriately matched to a user’s particular presswork requirements.

                        Comment


                        • #13
                          Re: Kodak "Thermal Direct" Plate

                          We have been using the Kodak Thermal Direct plates for 4 months now, and I can say that it just works great. We have no problem with press polution, development or anything. It just worked right from the start...

                          We have a speedmaster 52-2, and print alcohol-free...

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                          • #14
                            Re: Kodak "Thermal Direct" Plate

                            HI Fatboysmart.
                            Thanks for your input. Most people I have spoke to say the same, but there are companies who are still having proplems with run lenghts
                            which is leading to other propblems which is making me a bit hesitant to take the final leap.
                            Cheers
                            Gaz.

                            Comment


                            • #15
                              Re: Kodak "Thermal Direct" Plate

                              Since we are a very small company, we usually don't run more than 20.000 or so from the same plate. So I can't help you there...

                              Comment

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