A common question we get asked frequently by other Risograph printers is, 'How do you remove these strange lines that keep showing up?'
To kick this troubleshooting article off, there are a lot of names for these in the community:
- Unwanted Stripes
- Glitchy Vertical Stripes
- Racing Stripes
- Ink Gutters
- Ink Lines
- Ghost Lines
See the pictures of what we are talking about below.
These stripes occur when the drum is not used frequently enough and the ink inside it begins to stiffen up, and dry out. You heard that right, you aren't printing as much as you should be...
Also prefacing this to get it out of the way - we've seen folks mention that this could be related to the master's file format or master unit creating the gutters. While those variables can contribute to printing issues and strange lines showing up, the infrequent printing stripe issues we are referring to are easily identified by the 3 dark or 4 light ghostly lines showing up in the same locations. They are spaced evenly and consistently on the master; no matter the file that printed.
So moving along, there are three basic solutions for removing the unwanted stripes:
- Print more ...
- Ink cycle your drum
- Do a full break down and clean out of your drum
The first way and by far most preventative and easiest process is printing more. A comment I hear a lot of people say after encountering the issue, is that they only print a few copies "once and while".
The benefits of printing small batches is a big misconception in the RISO world. RISO machines are built and engineered to duplicate prints hundreds upon thousands of times! If the drums aren't running and spinning consistently with large quantities of prints, they are drying and locking up. Think of a RISO machine like a self-lubricating diesel fuel system on a truck... the more it runs, the more is lubricates!
And we're not talking about an increase from 5 prints to 20 prints. We mean increasing to hundreds of copies to keep your drum running smoothly. If you don't need to print that many copies, a better question to ask yourself might be, "why am I using Risograph then...?"
The second best way to remove the stripes is ink-cycling your drum. In our experience, this is the most consistent fix to remove the lines on each Risograph drum.
For this, you'll need a lot of sheets of cheap recyclable copy paper, and patience.
- First step is to 'drain' the drum...
- Create a master with a 'sky copy' or a 'test print grid', or something that will use a lot of ink across the whole piece of paper.
- Next, restart your machine in 'test mode' with the drum inside (usually hold 'left & right arrows with the power button'), and then run the command for your specific machine to initiate drum drainage, something like '0888'. After hitting start, this command will this will begin rotating the drum, forcing out all the ink still inside the drum, but not adding any new ink. This can take a few hundred copies, thus the need to find a good supply of recycled copy paper and, patience.
- The copies will start to look lighter and fade away as all the ink is forced out through the drum. See picture below:
- After the copy paper coming out is printing with almost no ink. Hit 'STOP'.
- Restart the RISO machine in normal mode, and print as you normally would. You should see the ink start to become come back to full strength again. Print a good 50-100 copies to reapply the ink with good coverage.
- Did the stripes disappear? If not, repeat steps 3-6 as necessary. Each time you repeat the cycle, the stripes should become less noticeable. See picture below:
If the first two ways didn't help, the third way to remove the ink stripes is to fully clean out the drum. I would not recommend this process as a drum break-down is a messy proposition, and not for the feint of heart. But check out these resources on how to clean out if you have no other alternatives:
- RISO MZ/EZ/RZ Drum Clean-out: https://www.stencil.wiki/how-clean-mzezrz-drum-change-colors
- RISO RP Drum Clean-out: https://www.stencil.wiki/how-clean-rp-color-drum
And there you have it. The lines/gutters/stripes are caused by the ink hardening in your drum, and are a sign you are not printing enough, so keep those drums moving!