Do I require a new K head?

[rjssigns]

If a damper is bulged or collapsed it's time to replace.

 

[player]

Interesting hypothesis. How would one test for that? If I apply, say, RVW-BK20A (95% black), it will pump out a bunch of black to achieve that, but still with the fine lines.

If you have not replaced the damper in a while, it is easiest to just replace it. I had a problem with a colour and was sucked in to replacing the head for $1800. (head + labour + travel). Shortly after the new head did the same thing. Changed the damper and it was fixed. So I replaced a head and spent $1800 when all I needed was a damper. Roland will not give any warranty on a new head if the damper was not changed, so the company got me twice. Anyhow it may not be the damper, but they have a fine screen filter in them that can get partially clogged, causing issues when printing but still give a perfect test print. I am not saying this is definitely your problem, but before I changed the head I would try the damper if it was my printer.

 

[Colin]

Hmm, ok, thanks for that; I'll run that by my tech and see what he says. When we replaced the head 9 months ago, he advised just leaving the existing damper in. It is nearly 5 years old, but not heavy use.

 

[Colin]

Tech said this: "If it was a damper it would fade out. A good test would be a block of each color to see if anything drops out".

 

[Colin]

Sorry to resurrect this old thread again, but this is driving me bonkers. As mentioned earlier, my new K head started giving the "lines" once again, about 6 months after installation. But what's perplexing me is that it's only doing it on RVW colors. To explain further, this is what I've just done:

1) Draw a 3" square in CorelDraw, and fill with an RVW color from the swatch book (RVW-ST17G).

2) Duplicate square and change the color from an RVW color to the CMYK values for that same color, shown in the RVW swatch.

3) Just for fun, duplicate again and change this one to RGB.

4) Export as EPS

5) Print all three at Standard quality / Media Type: OJ 3651 Matte / Halftone: Dither / Interpolation: Nearest Neighbour / Direction: Bi-Direction / Preset: Pre-Press U.S.


What I find strange is that only the square with the RVW color applied has the lines; the CMYK and RGB squares print perfectly. How can this be?

All feed settings are correct.

I really like using the RVW colors, as they are predictable.

 

[Andy_warp]

It may be a process control issue.

I've had to regiment every facet of my process to alleviate impacts of printing in a dirty, uncontrolled environment.
My machine takes $3000 heads (16 of 'em!!!)

We have sawdust, lint, dust, fabric fibers constantly floating about.

Also you mentioned "light" use. I've had operators think they were "saving money" by not running the machine when it is not needed.
If it's an inkjet...push some ink through it everyday. Once in this routine, you'll have all nozzles clear, and ready for business.

I do other common sense type practices too...like, if I'm sweeping I cover the machine...until the dust settles so to speak.

Many issues are blamed on faulty software/hardware designs. With more control over your processes, there are less variables.

 

[Colin]

Thanks for chiming in. The environment of my printer is painfully clean, so I don't think that's an issue. The new head printed RVW colors clean for a few months, but then the lines started appearing again.

I've been trying a pile of different settings when test-printing these three different color blocks, but nothing seems to effect it; the RVW always has those dreaded bands/lines. The only thing that made the RVW block print clean was un-checking the "Convert Spot Color" box in VersaWorks, but that then changed the color, so that's no solution.

Gah.

 

[iam808]

I had a similar problem with my machine recently. When printing photographs, light colors printed perfectly but blacks and shadows had banding, in the same pass. Vector files looked better but you could still tell something wasn't right.

Nozzle tests looked good to me...however trying to calibrate the machine became difficult because the black wasn't printing clearly so lining up little lines and boxes became nearly impossible. This lead to me using a printers loop and that's when I noticed black vector shape edges weren't crisp.

Roland replaced the head (under warranty, the machine is less then a 1yr old) and my tech noticed two issues. First the K head did not line up with the capping station properly, it was justified to the right a bit. Second, the print head was touching the capping station slightly.

 

[Colin]

...my tech noticed two issues. First the K head did not line up with the capping station properly, it was justified to the right a bit. Second, the print head was touching the capping station slightly.

Thanks. I'm no expert on these machines, but I'm wondering how & why an alignment issue with the capping station would result in the banding lines when printing. Also, as I noted, the CMYK and RGB colours print perfectly, it's only the RVW colors that have the lines, and this to me is just bizarre.

 

[iam808]

I'm no expert either...the tech explained that because the capping station wasn't lining up with the head correctly, that the nozzles weren't being completely covered when the machine was off. It's kinda easy to see if it's an issue, just look at the bottom of the print head.