Missing lines on plate.

[Karen]

We have a Heidelberg Creo Trendsetter 3230 and when the plate is printed the are fine lines missing in the artwork. The lines are very consistant about every 32nd of an inch. Any ideas on what could be causing this?
Our service guys believed it was the SCSI cord or the SCSI board we have replaced both and no change.

 

[nemo]

Are the lines vertical or horizontal? Positive or negative plates? Can you provide a picture?
If the lines run around the drum it may be banding or a stuck pixel - however 1/32 apart will contradict this unless your laser has a considerable number of pixels chopped or is overwritting.
Horizontal lines are either from the data path (SCSI, FDPE) or may be some artifacts due to air jet.

 

[kala]

just increase the thickness of the line and check whether its appearing in the plate or not ; if its appearing then there is problem in the expose side for very thin line..

regards
kala

 

[nemo]

just increase the thickness of the line and check whether its appearing in the plate or not ; if its appearing then there is problem in the expose side for very thin line..

regards
kala

The Trendsetter is able to image a 10 micron line that the plate won't even be able to hold... there isn't such a "thin line expose problem" on these lasers

 

[Karen]

Are the lines vertical or horizontal? Positive or negative plates? Can you provide a picture?
If the lines run around the drum it may be banding or a stuck pixel - however 1/32 apart will contradict this unless your laser has a considerable number of pixels chopped or is overwritting.
Horizontal lines are either from the data path (SCSI, FDPE) or may be some artifacts due to air jet.

The lines are horizontal on the plate wich is the opposite direction it moves around the drum. They are positive plates. We have printed a plate of solid black and these thin lines still appear. The SCSI cable and SCSI board have been replaced with no change in the lines.

 

[Karen]

just increase the thickness of the line and check whether its appearing in the plate or not ; if its appearing then there is problem in the expose side for very thin line..

regards
kala

We have printed a plate with just a solid black box and the lines are throughout the whole plate. Im not sure what you mean by increase the thickness. We don't want any lines.

 

[STSTech]

Karen,

The manufacture of the plate is who? Have you tried a different box of plates with a different lot number? Catch the plate before it goes into processor and rotate it 90 degrees. See if the lines shift.


STSTech

We have a Heidelberg Creo Trendsetter 3230 and when the plate is printed the are fine lines missing in the artwork. The lines are very consistant about every 32nd of an inch. Any ideas on what could be causing this?
Our service guys believed it was the SCSI cord or the SCSI board we have replaced both and no change.

 

[Karen]

We have tried different size plates, for different presses we have. They all have the same lines. We have small and large plates that are from different times. I do not think it will take a plate sideways.

 

[nemo]

The lines are horizontal on the plate wich is the opposite direction it moves around the drum. They are positive plates. We have printed a plate of solid black and these thin lines still appear. The SCSI cable and SCSI board have been replaced with no change in the lines.

Karen, on a positive plate the laser is burning the background leaving the active pixels untouched. The burned area is washed out in the processor.
For a full 100% solid plate, the laser will not expose any pixels. Please reply with plate type to confirm.

Did you try to send a plate rotated 90 degrees in the processor?
Please try to upload a closeup picture here. I will most probably be able to tell you what is causing it.
I doubt this is a data path issue but to bypass the SCSI board you can load a plate and run an internal plot (plot 33 or plot 50) and see if you still have lines.

 

[Karen]

The problem was with the FDPE. We replaced the board in the machine and the lines have gone away. We had replaced the SCSI board in the computer and cable but not this board. Thank you for your help.

 

[Al Ferrari]

I realize the problem has been solved with replacing the FDPE board, but wanted to comment on the processor not taking the plate sideways:

Since you don't need to put this exposed test plate on press, just cut it to a size that will process rotated.

Al