Mimaki CG-STii plotter won't read crop marks - ideas appreciated pls.

[Ian Stewart-Koster]

(P.S. That should be CG-SRii, not STii, but it won't let me edit the title)

Firstly, it's a lovely plotter, and Finecut, operating from Win 7 was great too. (problems getting Win-10 to load Finecut, but that's no great issue- we just use an older PC instead.)
But we bought the plotter with history unknown, and it will simply not register the crop marks.

It goes looking for them , passes over them, and then returns an error that it cannot find them - despite them being the size that it wants, in the places it wants, and starting off with the LED inside the L shape.

I've cleaned the lens with isopropyl aclohol. There are only 2 wires going to the LED, so I'm not sure how the sensor gets its feedback back to the rest of the machine, unless the same 2 wires can carry a signal back.

I've tried all the suggestions I can find all over google and here, about settings - all the settings are correct. It's as if the sensor is blind to the crop L shapes.

Is the head changeable, or is the black plastic LED & sensor removable? It looks rigidly fixed, and looks to be screwed on from underneath the head, which might be a pain to have to remove.

Thanks in advance for any thoughts or ideas.

 

[Solventinkjet]

Which type of crop marks are you using? Type 2 the laser should be outside the L. I believe that model does have a sensor sensitivity setting in service mode but I haven't worked on one in a long time. I would see if you can get a service manual for it.

 

[Ian Stewart-Koster]

Thanks for the reply. I'm using the normal ones like four letter L that stick out past the boundaries. I've forgotten the type number, (1 I think) but it is correct for the type I use.
I used Finecut to set them in the original file, before sending the PDF to the HP Latex printer.

Service mode sounds very useful... I've only got the poorly written user manual. in paper, and 2 downloads of the same thing.
It does plot properly, if you simply send it to plot some text. Just don;t expect it to neatly and carefully follow magenta cut outlines in the right place without finding the cropmarks and detecting any skew, first.

Thanks

 

[Ian Stewart-Koster]

I found a service manual & parts manual on Ebay.
We'll see what it divulges... after I get the download link. Thanks for the idea.

 

[Andy D]

Do you have it set up in the plotter's on board LCD screen to look for the right type of marks?
If so, does it find any of the marks before it errors out?
One thing I have had to do is take a pen and darken up the marks if they print too light.

 

[Andy D]

A couple things came to mind:
You might want to try exporting to your rip in another file format, I always used Tiff
Some media makes it hard for the plotter to find the marks, like reflective... Are your marks dark black on normal white vinyl?

 

[Ian Stewart-Koster]

Thanks for both replies.
The black marks are nicely black, to me - as good as 100%K as I'd like, and are about 10mm long x 2mm wide.
I can try and go over them with a felt pen, but I'm not sure it'll make any difference.

Using the console on the plotter to search for crop marks (via the Function key & Enter key) also makes no difference - it moves about, back and forth, and then returns a 'can't find crop marks' kind of message - whether it is searching in the right place or not.

The service manual has just downloaded, so I'll suss it out...
Thanks again,
Ian

 

[myront]

What about your layer structure. We print to an HP latex and cut via a mimaki plotter with FineCut. All the reg marks, layers, etc are set up in corel first. Are your marks on the correct layer?

 

[Ian Stewart-Koster]

Thanks, yes, we auto-created the crop marks/reg marks in Finecut, just like that, too, before exporting to PDF and printing on teh L260.
The plotter itself cannot seem to find the marks though, when it is told to look for them. The head moves as if it is all happening correctly, but then the error message appears.

 

[myront]

It does sound like that sensor/camera has gone bad or possibly have a piece of vinyl stuck on it. I'd study how to remove that whole head just enough to view the underside.

 

[Andy D]

Thanks for both replies.
The black marks are nicely black, to me - as good as 100%K as I'd like, and are about 10mm long x 2mm wide.

I have had issues with marks that look dark but were 100% K for some reason, but when I changed them to something like 50%C-50%M- 50%Y-100%K it worked fine.

I'm not sure you understood what I meant, go into your plotter's LCD and tell it the size, thickness, type, and quantity of marks.. and going from memory, there is an auto detect function that sucks, don't use that.

 

[Andy D]

Also, I don't know if it makes a difference, but this was the type of marks I used and where I placed the laser:

 

[myront]

Does it fail on the very first reg mark or goes around finds each then fails at the last one?
Fails on a large print (more than 10ft) or fails on any size?
Watch the edge of the material is it "walking" a good distance (more than 1/4")?

 

[Ian Stewart-Koster]

Thanks, Andy, I'll go and recheck, but as far as I know it was exactly that which you had. 10mm long, about 0.5mm thick, type 1, four of them, 5" from the leading edge, 3" from the nearest side,

Myron, thanks, I did get a service manual, and i see the sensor if much further back than I thought. I'll go and see if maybe a bit of vinyl is accidentally stuck over it.

 

[Ian Stewart-Koster]

WOW! It works! At last - after 2 years of owning this beast!

I thought the sensor must have been near the LED, but after buying the service manual, I saw the sensor was actually right at the BACK of the carriage head.
Being only 2.5mm gap, doing anything was hard, in the cleaning department, so I drenched some tissue cloth in Isopropyl alcohol, and folded the paper in three, and passed it underneath, front to bacl, and moved it about a lot.
I did that 4 times. I couold not see appreciable dirt on the cloth, but when I restarted the plotter,it successfully found all four marks, then when I sent the file to plot, including another mark detect, it found them all again, and is now plotting.

Thanks heaps! The euphoria is amazing after so long of failed attampts!

It did a fair job. The left & right alignment was maybe 1.4 mm out, but front and back was a bit worse. However the vinyl sat for 4 months.
I'll allow that it or the backing might have grown or shrunk.

I'll have to redo the offsets calculation now.