Kingston

Hello,

I have a bit of a dilemma here. In the past I have used this one sticker shop for creating stickers for my front panel designs. They have been spot colored with high quality ink and materials, very heat proof and they will absolutely never come off under any circumstances. I have used foil based stickers and transparent stickers. It's the same stuff used in professional advertising applications. Spot coloring means I always use just one color, a strict qualification in order to make sure it ends up perfect using RAL color charts.

This has worked well, but the shop I use has a quality control issues. I can see the pixels, and sometimes even tiny pieces of graphics are missing. For casual user of the gear these will probably be never noticed, but it matters to me. Maybe their spot color printer is a bit old, but it's still strange to see the actual pixels since I provide them PDF vector graphics, unlimited DPI.

These kind of sticker prints are a bit expensive, because the guys want to deal with hundreds of copies, and I need just one or two. But this is the only shop I've found that even does one off prints.  :( Many shops I contacted were even a bit rude when I asked about having one off stickers made. "quit wasting my time, I have better things to do".

Are any of you people out there familiar with what I'm talking about? Could you direct me to a shop that meets my specs above, but does not have quality control issues?

Mike
« Last Edit: August 22, 2011, 07:42:09 AM by Kingston »


detonator

I have 3 cutting plotters over here. Provide me an Illustrator document and I'll send you a free sample


I deal with vector rips a bit at work, so maybe I can help a little.  We're printing conductive ink with 10um features, so we've run into lots of ripping issues in the past. 

I'm assuming this is inkjet printing?  If it's screen printing, see the bottom of my response.

I might be telling you stuff you already know, but here's my insight.  Ultimately any vector art will have to be ripped into a pixel format.  This can be done either at the printer driver, from the vector program, or in a specialized pre-press software, such as EskoArtwork.  The fact that you can see individual pixels tells me that the rip isn't at high enough resolution.  They might be applying a standard DPI (or DPCM in your case) setting that works for advertising, but not for your application.  You might ask them if they can do a finer pixel size, but they might be limited by the print head. Some wide format industrial inkjets have pretty large droplet sizes to increase throughput.

Regarding the missing pixels, this could be a dirty print head, or it could be sampling/aliasing if the resolution of the rip is too low.  In my application, I'm printing 10um lines at 500um spaces for conductive grids for solar cells.  If the image is ripped or printed at <1200DPI, entire lines disappear (similar to recording a 20KHz sine wave at 10KHz sampling rate, every other peak disappears).   Between 1200 and 2400DPI, the lines move due to aliasing and we get bad moire patterns.

If it's screen printing, then the pixels are a function of the mesh size being used.  The mesh's thread count defines "pixel" sizes.  You can make a screen with a 2400DPI photomask, but the mesh will still "downsample" the print to the thread count.  There are some fine polyester meshes available for printed electronics with resolutions of about 50um, but these small apertures are prone to clogging and can themselves cause missing areas of the print (particularly in lighter tinted areas).  If it's a screen print, let me know and I can suggest a source for finer mesh screens, but in my experience, screen printers often make their own screens and are hesitant to try new meshes or third party screens, particularly for small runs.

-Chris

Kingston

detonator, thanks for the offer. I'll prepare the set and get back to you.

Emperor Tomato Ketchup,

thanks for the detailed explanation. I think what they use is a "cutting plotter". I guess it's an ink jet, but used with spot colors and not the consumer standard CMYK pattern. They also had about a 0.5mm tolerance for the sticker cuts, and I had to take this into account when aligning the cuts. I basically have two files, single color print for all the graphics/text, and a separate cutting guide.

I doubt the issue here is being limited by the print head. Why else would I see the actual square pixels? the droplets should be "round". I think it's a conversion issue somewhere along the way from the vectors to the printer. The missing graphic is nothing like you described. Here's an example, the pixel issue itself is not visible in this low res photo.

http://www.michaelkingston.fi/files/Kingston-PM670-FP1.jpg

There a whole letter missing in the word "slow". Looks like some strange a copy paste or conversion error again. That certainly isn't visible in my PDF file. In some other projects there have been parts of a letter missing etc. I'm starting to think their software or printer drivers are buggy or outdated.

And that's why I need a shop that has more attention to detail but still does cheap one off projects.

By the way the above picture has two kinds of stickers, foil stickers for the pink/purple parts (foil only visible in the fonts and graphics, pink/purple as the spot color). And a transparent sticker with black ink for the middle white area.

Mike
« Last Edit: August 22, 2011, 11:37:40 AM by Kingston »

OK, I understand better now.  I agree it's a software/driver issue if the pixels are square and if whole letters are missing.  It's probably a good idea to ditch this vendor.  It sounds like you need not only digital printing, but plotter printing specifically so that your stickers can be cut to shape without needing to get a die made.  I don't have much more to add, other than good luck and I hope Detonator can help out. 

Edit:  If you can get by without the plotter cutting (rectangular stickers), then there is one more option if Detonator can't help: A printer running an HP Indigo press might be a good option.  This is a digital liquid toner system capable of making offset quality prints, only digitally.  I believe they can also do spot colors.  The liquid toner is very durable too, since it's a thermoplastic that is fused into the substrate when processed.  These presses are designed for high quality, low volume printing.  It might be worth looking into as a backup.

-Chris

Kingston

Re: Stickers and using them for front panel graphics. High quality needed.
« Reply #5 on: September 19, 2011, 10:49:16 AM »
Hi guys,

still looking for a sticker print shop and/or cutting plotter service with the high quality specs discussed in the above posts.

Re: Stickers and using them for front panel graphics. High quality needed.
« Reply #6 on: September 19, 2011, 11:31:19 AM »
Hi Mike,

In fact before I started engraving I used stickers all the time, and supplied some here too.

I have a very good friend Dan @ http://www.hollographics.com/

Now they make all sorts, whether it meets your specs is for you to decide.

it may or may not help.

Best
Pete

Kingston

Re: Stickers and using them for front panel graphics. High quality needed.
« Reply #7 on: September 26, 2011, 05:30:22 AM »
Thanks Pete,

these guys are expensive. At least they do singles, but they have a minimum order of £50 + shipping. Like always, they are great for big batches, but I still need just one or two sheets, and fifty quid is too much.

I was looking for better deals.


 

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