speedmaster 52 marking

we are having problems with marking on printed image looks like the sheet is hitting on something between units,cleaning transfer cylinders resolves problem only sometimes,am new to press

 

Is it marking on a particular stock, is there any packing behind the transfer jackets.

Regards

 

seems to be mainly on self adhesive stocks we are uv ,even though the synthetic stocks do not have a grain they have a memory from being in roll form before sheeting ,it has the same feel as grain ,could this be the problem as we sometimes go against the memory ,not too sure about packing behind transfers if there is could that be a problem what are the recomendations,

 

The packing behind the transfer jackets really depends on the stock thickness. Obviously this wouldn't be changed everytime you changed paper thickness but there needs to be a minimum behind the jacket so the stock is travelling at the same speed as the machine and doesn't flap. If the transfer jacket is underpacked this is where marking can come from as the sheet can then drag. You could start by putting a .3mm (yellow) sheet behind the jacket and see what happens.
The jackets also need to be kept clean and have a thin layer of gum as this also helps stop ink from transfering.

Regards

 

Cheers for the information I will check this tomorrow at work ,Thanks

 

Hi sinclair
are you using anti marking nets which can be attatched to your transfer cylinder removeable jackets, if not then try some ,if you are make sure they are clean. regards johnyprint

 

Definitly pack the transfer jackets. Usually I will tell guys to pack at .004 over their thickest stock. If thinner stock has a marking issue you may have to pack for a specific paper.

 

Use superblue on the transfer drums???

 

Maybe the original posters company doesn't have the required thousands of £/$ to convert from what is the standard system ( which works just fine if looked after correctly ) to the super blue system, plus he is using self adhesive and synthetic stocks and UV ink.

 

make sure your tail vacumn is working and set to the correct lenght of sheet also check the eye between units with a clean white cloth to see if the sheet is slapping against it after release from hold down vac.

 

Unfortunatly a straight SM52 has none of the above !!

 

Can you control the problem with a speed adjustment?

 

To isolate the problem, run under impression and hit the E/stop button. Leave the sheets in the press.Then go look at where the marking begins by going through all the units. Lift the cat walk guards and check. You will then see where the marking starts, and in turn you will be able to check the transfers where the marking begins.

This way you could hoefully solve your making quickly.

P.S. - Super Blue is the way to go...

 

marking problem

after tracking down your marking problem you can place rubber bumpers on the transfer cylinders in the area that would be covered by the sheet in a non image area. i like to use little strips of the foam tape thats used under the ink fountain foils. putting these bumpers on the transfers will support the sheet in the troublesome areas and get you through a job. remember to remove the bumpers after your done running that form

 

yeah I used to use the weather stripping foam tape or sometimes velcro , its a bad feature of the older speedmasters but you got some good advice here and it can be resolved.....