Master wrinkling

[sklemetti]

When I make a master of an 11X17, the master wrinkles in the last portion of the printing area. The wrinkles print and won't come out.

Any ideas to prevent this.

Riso GR 3770

[Kev]

No help but

Sounds like the same problem I am having with one of our machines. fine wrinkle across the trailing corner. Can be either side. Small, but enough to make 10pt text difficult to read. Maybe someone out there has encountered it & cured it. If I find a solution I'll get back.

[Kev]

Progress (or lack of) - Have removed & cleaned pressure roller & reinstalled back to front. Pressure setting was out by about 5mm. Have corrected that. Inspected rollers in master feed area. All seem ok. Slid a piece of card through the cutters as suggested elsewhere for a different problem. (In case something there was causing the master to run off). Seems to be a slight improvement after all that. OK now for text, but wrinkle marks still show on a plain graphic. seems to now be confined to one corner. That corner prints lighter on the print that comes through with the master making but not in general printing.
Should mention have 2 machines & seven drums. Problem is with all drums, only on one machine. Out of time for now. Thinking I need to have a closer look at the pressure roller mounting.

[20gaugeO/U]

There are about 8 items that I can think of that cause this. But the last one I saw that had this happen to it nothing fixed it. The only thing left was the write roller. Riso doesn't have/make them anymore. Haven't for a couple of years.

Open the silver master side door. Try putting additional pressure on the master roll flange with your finger while it is burning/loading the master.

[Kev]

Thanks for the input 20gauge. Tried putting drag on the master roll flange. Inconclusive. Possibly worse. Also tried from a slack loop of master. Still working on process of elimination. Making a 'confidential' master works perfectly. Master goes on to drum with no creases, which seems to clear the feed rollers & cutter. Made a blank master (copied from a white sheet of paper) Slight creasing. Always trailing edge of master.Machine is a very low count, about 800,000. Was gathering dust in a corner of a small print shop when I bought it, but had been mal-adjusted in several areas. eg main drive belt out by 1 cog. Will try interrupting the process next to see if the master is creased when it goes into the stocking bin. This is becoming personal! Out of time for now.

[olgawilson]

Wrinkles? Try this anti wrinkle moisturizer It reduces the appearance of fine lines and wrinkles, leaves skin soft and rehydrated...

[Kev]

Thank you Olga

Decorative but useless.

[joelsa12]

Like said before there are many issues that can cause this!

If the master is wrinkling it is getting crooked somewhere in the process. So something is causing unneeded drag on one side or you have too much pull on one side. First clean all the loading rollers. The write roller and the P roller. Which is the little roller before the write roller. Also clean the roller after the write roller. It is a segmented roller and I have seen a dirty one of these cause the problem that you are speaking of. I have actually had to replace this roller(this is no fun) to get rid the issue that you describe. I would also check the magnetic brake on the p roller. This can get clogged with debris and cause the same issue that you are talking about. Also an easy one to check would be to make sure that the end caps for the master roll are not worn out. I have one end cap be able to spin freely inside the master roll. This also will cause your issue. Last one off the top of my head would be the unit that the master roll fits into. There are brakes inside of this also. I have seen one of them go bad and cause your issue. Good luck with your search! Olga may I get some of that lotion?

[Kev]

Thank you. I will keep trying, but neglected paper work (office) has caught up with me for now. Given the gross mal-adjustment in other areas, thinking I should check the timing of the whole feed/write area also. Will get back, but may be a couple of weeks.