Mysterious Blanket Scum & Possible Solenoid Problem?

[Pajamathom]

Hello All:

I am coming to all of you again with two problems (2 photos attached)

Problem 1: I am getting ink buildup on my blanket somehow. Ironically enough, it is building up where there is no plate contact. Where could this ink be coming from? Form roller 3?
I have just purchased new rollers and installed them while checking pressures to the plate. The blanket is 2.5mm thick. Is this too much that it is making contact with Form roller 3?

Problem 2: (refer to Photo 2) When opening up the side panel and observing the press as it operates, I set the operator lever to station 4 (Plate makes contact with the blanket) and what seems to be the plate solenoid activates (metal rod is pushed up; marked blue in photo). When setting the operator lever to station 5 however (blanket makes contact with impression) I do not see the metal rod push up to engage this (marked red in photo). Is this supposed to engage when at station 5 on the operator lever?

Thank you for all your support

 

[turbotom1052]

The buildup of ink on the outside of the sheet is a normal occurrence. As much as we would like to think that the non image area of a plate is just that (a non image area) there is often minute traces of ink in these areas that over time ( a thousand or three impressions) will build up on the plate, transfer to the blanket, and even make it to the outside perimeter, and build up on the impression cylinder. Your best chance for minimizing this buildup is to be sure fountain solution is not only the right mixture but that is also clean. That all rollers both in the inker and dampening system are set right, and that form rollers have minimum side to side play, and that if your press is equipped with delta dampening its only used when needed.

 

[aqazi81]

AS Turbotom already stated, this is a normal ink buildup.

 

[pdan]

Problem 2 - plate only goes to blanket while paper is is being fed.
The amount of ink in the non paper area looks excessive to me. Change developer or increase the plate development time.

 

[SheetSqueezer]

Hello:

I am coming to you again with two problems (2 photos attached)

Problem 1: I am getting ink buildup on my blanket somehow. Ironically enough, it is building up where there is no plate contact. Where could this ink be coming from? Form roller 3?

The plate contacts the blanket all the way across both of the cylinders, wherever the two of them meet. Photo #1 shows ‘picture framing’, or tone buildup on the blanket where it is outside of the paper size area. That faint toning is actually everywhere on the plate, all the time, and is constantly being transferred to the blanket. It is then being removed by (printed onto) the paper when it travels through the press. The tone you’re seeing on the blanket (and probably impression cylinder) is a buildup over time, where there is no paper to remove it.

I have just purchased new rollers and installed them while checking pressures to the plate. The blanket is 2.5mm thick. Is this too much that it is making contact with Form roller 3?

Thank you for your support

The rollers on a printing press are surrounding the plate cylinder only, so it’s not possible for any of them to come in contact with the blanket cylinder.