Speedmaster 74 Marking problems on heavy stock

Discussion in 'Heidelberg Printing Presses' started by evenslimmersladey, May 8, 2010.

  1. evenslimmersladey

    evenslimmersladey Member

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    Having recently moved from a 74CD to a straight 74 I have come across the long forgotten marking problems on stock above 300gsm. The more ink coverage the more the job marks.
    The press has the orange jackets on the impression and transfer cylinders that are cleaned on a regular basis. H/berg have been contacted by phone for the correct packings under the jackets which has been done.
    Will I have to spend my time swapping units, putting down draught excluder and wiping wiping wiping or is there any other method that will aid this problem?
    I have tried putting on plate cleaner and polishing dry which is supposed to repel ink but to no avail. Running the press at different speeds is no help.
    Putting back the original metal jackets has not cured the problem.
    I do not use superblues as these tend to crud up very quickly.
    If anyone has any ideas it would be a BIG help.
    Many thanks.
     
  2. turbotom1052

    turbotom1052 Senior Member

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    i hate superblues!!!! if not on a cd i prefer the jackets too. one thing ive found about the jackets is that you CAN NOT clean them with any strong solvent like mrc or acetone. acetone based solvents will quickly wipe away the ink repellant film that the orange jackets come with. its also important that the jackets are packed correctly. off the top of my head i dont remember what that packing is supposed to be but ive tried many different combinations of packing till i came up with the best compromise that i woul be able to run the widest range of sheet thicknesses. then theres always the tried and true bumper method of eliminating marking problems. should be noted that the ink repellant film on the orange jackets are also repellant to the most commonly used "bumper" materials. ive found that one of the only things that stick well to a new orange jacket is high quality velcro strips.
     
  3. evenslimmersladey

    evenslimmersladey Member

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    What do you use to keep your jackets in tip top condition?
    Is there a particular product that is available to clean the jackets?
    In the term bumper materials, do you mean draught excluder etc?
    Heidelberg technical told us to put 0.5 behind the impression cyls and 0.3 behind the transfer cyls.

    Thanks for your help by the way.
     
  4. The Heidelberg Guy

    The Heidelberg Guy Senior Member

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    Take off the orange jackects an install the Heidelberg factory jacket. Pack as you normally would to start, cut out a sheet of the stock you are going to run about 12"x12", and place it in between the impression and first transfer. At this point, you want .010" (the tighter the better without any resistance) clearance between the paper and the transfer, depending on the coverage, you may want to go a few thousands either way.

    Make 100% sure that your double sheet detector is 100% functional, and set proplerly.

    Clean the jackets well, and use silicone (spray on and lightly buff off)

    Should be good to go!
     
  5. evenslimmersladey

    evenslimmersladey Member

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    Many thanks for your reply.
    I assume that I continue working down the press using this method?
    Can this method be used on the orange jackets as I think that one or two of the original jackets are damaged (before my time)
     
  6. The Heidelberg Guy

    The Heidelberg Guy Senior Member

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    Yes, do all of them that way (1st Transfer), standard packing in the 2nd Transfer (under the water pan roller) and i would use your orange ones in the 2nd position, they tend to mark less.
     
  7. mrheidelberg

    mrheidelberg Senior Member

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    and just make sure your production schedule doesn't swap between thick and thin stocks too much or you could find your makeready times to be a bit long with all the transfer jacket packing checking and altering !!!
     
  8. turbotom1052

    turbotom1052 Senior Member

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    i dont know of too many places that would be too tolerant of adding the additional time to a makeready that would allow for a transfer packing change evey time you went to a different thickness sheet. thats why i look for a compromise that will work for the most commonly run stock thicknesses. if i have to run a stock that falls out of this range and encounter a marking problem i resort to using bumpers to get through that job. changing the transfer packings on a 6/c press would be way too time consuming.
    in response to evils question about "bumpers" the most common ones ive used include weatherstripping or the foam adhesive tape that goes under the duct foils. ive not a clue as to what draught excluder might be.
     
  9. heidi_helper

    heidi_helper Member

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    Clean superblues work, pack as needed only, and move the transfer suckers as needed....sure you tried that all....but.... Take out the superblue packing, new superblue nets, stretch them TIGHT!!!! Sides too... I like to install them tail first, reverse them on and tuck the slack under the lead flap. Also, try turning OFF THE TRANSFER CYLNDER VACUUM SUCKERS.... Please don't ask why. I don't know. But it works most times. The orange covers mark worse than anything because they follow the shape of the cylinder, which has holes....the cut outs mark. go back to the origanil Heidelberg and try these tips... There's more too....hope this helps anyway
     
  10. mrheidelberg

    mrheidelberg Senior Member

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    Of cause they do thats what they are designed for........they are a consumable and need to be replaced when dirty, they are not there to be used for months at a time without getting some kind of marking issue. The costs of the nets need to be allowed for in the general day to day running of the machine.
    There are many Superblue alternatives which are cheaper and are meant to work as well........but they don't.
     
  11. heidi_helper

    heidi_helper Member

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    I agree with mrheidelberg....superblues are the way to go. We had the orange covers in the entire press and one by one removed them, went back to superblues. But somehow its better with almost all thickness stocks having no packing. And most times when marking occurs, we turn off the transfer cylinder pumps and that solves it. However, again I agree with mrheidelberg, they need to be replaced as needed. I also agree with the heidelberg guy, if you must use orange covers the second position marks less than the first. And I strongly agree with turbotom, cleaning the orange covers with mrc or anything more than the recomended 50/50 water and blanket wash mix will immediately trash the cover. It not only destroys the delicate surface but seperates the surface from the backing its glued to. The same as the old perfector unit orange covers.
     
  12. evenslimmersladey

    evenslimmersladey Member

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    I have used superblues on an old 72 and the problem I found was that they were great when new unless a large coverage solid was being printed, when lint was pulled from the new superblue making the solid very fluffy and not at all acceptable.
     
  13. heidi_helper

    heidi_helper Member

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    Now, this topic is going somewhere. We now still use the Superblue covers (jackets) but use a new orange net on top of it. It is 30% less cost then the original superblue nets, and truthfully I think the quality is better. Somehow the original superblue nets have lint and wrinkles now. But these orange nets (not the orange jackets) seem better. I'll get the product info. Post back soon as I can.
     

  14. evenslimmersladey

    evenslimmersladey Member

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    Thanks guys for all your input. Much appreciated.
     
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