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  • LITHO SEALING GLOSS

    Hi there,

    my new manager has posted an email to all production staff stating that all jobs printed on gloss should now be sealed. In my experience this is not something which i have ever done. Is this something everyone else does? We have a aqueous coater on my press which never gets used as it doesnt feed very well on the folders once emulsioned, any input on this?. As you may have guessed my new boss is the finishing manager. I have mentioned that on some jobs we run heavy four colour to the edges of the sheet and a layer of sealer on top pay increase set-off but it has fell on deaf ears, the reason he wants this is because two sections have marked on the stitch n trimmer. All input would help as im trying to find a balanced argument to approach him with, and does sealer count in the TAC and is it counted as 100%?

    Paul

  • #2
    Re: LITHO SEALING GLOSS

    Paul
    the only time I see machine sealed jobs is when we have B1 work printed outside and we have to wait until the next day for iy to dry.

    As far as coating is concerned - we dont have any problems with folding - we did have a problem this week of marking on white paper on a saddlestitched job - which was put down to too much pressure. apart from that no problems (we delivered about 150 jobs this week)
    We do coat coated work as well.

    I dont know what else to say

    Peter

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    • #3
      Re: LITHO SEALING GLOSS

      Thanks for the reply Peter,

      Nice to get another opinion, guess most things will head towards making finishing easier. probably at the companys expense.

      Paul

      Comment


      • #4
        Re: LITHO SEALING GLOSS

        Does anybody litho seal gloss?

        Comment


        • #5
          Re: LITHO SEALING GLOSS

          I have just had our local town magazine delivered - 7000 48pp on 150 gsm gloss - and I can smell the varnish from here - It was printed on a long perfector

          Peter

          I don't mean I have had all 7000 copies delivered just the one to home

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          • #6
            Re: LITHO SEALING GLOSS

            Paul and Peter:
            Just what is Litho Sealing Gloss? I've never heard that term before.
            Is it aqueous or just varnish?
            John Lind
            Cranberry Township, PA
            724-776-4718

            Comment


            • #7
              Re: LITHO SEALING GLOSS

              Hi john,

              hows you gas ghosting problem? Sealing is a term used to apply a neutral varnish to a printed sheet. It is done on a priting unit with a litho ink without pigment in, eg 100% vehical (sp) . What do you call this then?
              I assume you call this a varnish, in which case do you varnish gloss stock to avoid rubbing, scuffing etc.

              Paul

              Edited by: Paul Green on Feb 12, 2008 5:51 PM

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              • #8
                Re: LITHO SEALING GLOSS

                Paul:
                Still wrestling with the ghost problem. You'll hear more in the near future. The ghost was revealed with the "litho sealing gloss". Now I have more marking problems to go with the ghost issues. What a mess.
                John Lind
                Cranberry Township, PA
                724-776-4718

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                • #9
                  Re: LITHO SEALING GLOSS

                  Dear Paul.

                  I am new to this website and have just stumbled upon it!
                  I am an experienced UK based printer and hope I can help you with your aqueous coating troubles.
                  The feeding problems on folders etc could be due to either too much pressure between coating distribution roller and blanket: Thus causing a bead at back edge of emulsion -which will stick -try reducing nip pressure, watch for low spots in emulsion film! A thorough manual airing (Fanning) may overcome this problem.
                  Another cause could be re -wetting. This is when, on 2nd side of print run, the heat is too great and moistens the 1st lick of coating, thus causing 'Blocking'. This will affect most areas of printed sheet, try reducing I.R. lamps by 2 to 5 degrees.
                  The only other possibility is your spray powder. It is not required theoretically, but in practice it is essential. Volume sprayed is minimal, on 1st pass through. I always increase on 2nd pass. (This is obvious to a printer).
                  However: Is your spray silicon coated? Conventional spray is not, and the water in coating can dissolve it!
                  I hope this helps you, and I am sorry your post is over a month old. Most of work I print is coated, mainly silk stock, but some gloss. I use satin coating, gloss coating can be troublesome. If using gloss coat, make sure it's double sided spec'. Best wishes, Alex

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                  • #10
                    Re: LITHO SEALING GLOSS

                    HI Alex,

                    thankyou for taking the time to reply, its nice to hear how other people in the same situation approach things. As this website is hosted in the US i find it difficult to explain the difference between sealer and coating, sealer being a ink vehicle without pigment and coating or emmulsion being water bassed with solids in suspension (i think). Our main issues were sheet curl on the finninshed stacks being more than the finnishers wanted, this was not excessive, it was as good as ive seen othe rcoaters produce but as the finninshing manager calls the shots it was abandoned. We were very carefull to get things right from the start, checking viscosity and breaking film to ensure minimum preassure was applied but as the coating leaves a more slipppery finnish than a sealer the finninshing would claimed issues feeding when folding, which is why now were in-line sealing jobs on the fifth unit with the coating unit virtually un-used. Then we were requested to in-line seal gloss sheets to protect them form marking and rubbing which all us printer dissagreed with but it forced upon us, i was under the impression that gloss should never need sealing on general four colour work as its a smother surface, its got to th epoint now where were sealing uncoated work as well. Any oppinions

                    Paul

                    Edited by: Paul Green on Apr 4, 2008 6:09 PM

                    Comment


                    • #11
                      Re: LITHO SEALING GLOSS

                      Hello Paul.

                      I am pleased that you received my post after so long.

                      The curl you describe is caused from a water based coating, on a specific coating unit, ( i.e. heat from lamps, hot knife etc) then I am afraid this is one bugbear which is almost impossible to overcome, especially on thin stocks. Trailing edge decurlers seem quirky on all presses I have run! The thinnest stock we coat is 0.10mm thick, with standard coating specification.

                      As you have a coating unit, In line sealing ( from duct ) on coated stocks, defeats the whole object, what's the point of having that facility and not using it??!! unless you are printing on uncoated stock, to minimise rubbing etc, or coating unit is awaiting repair / cleaning.

                      There is no reason why you should revert back to these methods on coated materials, we don't have any problems dealing with curl, yes it can make things tricky, but that's printing. As for gloss stock being inline sealed, there really is no need generally. Our finishers can more than handle these issues and top quality is achieved almost all of the time.

                      My instinct tells me the problem lies post printing, and I would push in that direction.

                      Why is a finishing manager calling the shots? Is he an experienced printer?

                      Hope this helps you.

                      Alex

                      Comment


                      • #12
                        Re: LITHO SEALING GLOSS

                        Hi alex,

                        I agree with you that moving back to inline sealing for coated stock is a bad move, i argued this at the time but it was seen as if the finnishers are having issues then its detremental saving the time on the press. My finnishing manager is now my production manager and that is why now gloss jobs are also coated in-line, even if its just for cutting after printing. Your guess that i should push in the direction of post press is 100% correct but as you can see that can go nowere unless my manager is prepared to mabe a public u turn and change his decision. Just as a note my manager has 0 printing experience, he may understand basic technical knowledge of print but no more than my partner would after me boring her for years about my problems, he does understand finishing more than i ever will but saying that i wouldnt take a job as finninshing manager.

                        Paul

                        Comment

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