Problems with toner pulling off of poly plates during run

[Valley Printing]

Lately, we have had a problem with the toner, coming off of the poly plates during a run. We use a HP 5000 to make the plates, and Genie brand plates. We always use the HP brand toner as we have had this trouble in the past with generic toners. The fuser is heating, and is very hot. When the plate comes out of the printer, if we scratch the plate, the toner will not come off, but after a few runs on the press it starts flaking. Need help, please!

 

[graficworx]

Generally it's probably a fuser problem. It only takes a few degrees of difference to become a problem. Alternatively, have you changed any of the press chemicals you are using (fountain, wash, ink, etc...).

 

[BillJ]

Also make sure you are using the lowest amount of toner that gives a good image. Too much toner will crack and come off in flakes.

 

[Valley Printing]

The toner is set to a low setting, the problem could be the fuser, but we'll get good plates and bad plates with no consistency. And when it flakes of during a run, it's usually not over the whole plate, just 1 or two small area somewhere on the plate. We replaced a bad fuser a few years ago, and when it went bad, we had flaking almost over the entire plate.

 

[graficworx]

Fusers can go bad in several ways. A fuser is essentially a heating element, and when they start to go bad they often will not produce even heat. Also, if the rollers are wearing uneven or getting hard they can cause un-fused spots. These HP printers were not designed to run thick stocks like the laser plates, so the fuser squeeze is very high on the poly plates. This helps get a good fuse if everything is working properly, but they can wear out. A life of a fuser depends on the paper type and page count, but a couple of years of poly plates every day would be normal. There really isn't much in that machine to replace other than the fuser and drum.

You mentioned some plates flake and some do not. Does the flakig have any pattern you can discern?

 

[Valley Printing]

No. We ran 10 polys today, only one flaked and it was on the right had side of a letter "A", we made up another plate, and it ran fine. I can't really discern a pattern. Sometimes it happens on the left side, sometimes to the right, sometimes in the middle. I thought it might be dirt on one of the rollers coming off the roller before the toner is laid down, but it's always in a different place.

 

[graficworx]

No. We ran 10 polys today, only one flaked and it was on the right had side of a letter "A", we made up another plate, and it ran fine. I can't really discern a pattern. Sometimes it happens on the left side, sometimes to the right, sometimes in the middle. I thought it might be dirt on one of the rollers coming off the roller before the toner is laid down, but it's always in a different place.

That pretty much rules out the fuser if it changes sides. Was this a new box of plates that it started happening with, or a new plate supplier? Sounds almost like there was something on the plate thats keeping it from fusing properly.