2 days of tech, printings and the such... still have problems

[NEGD]

Ok, so here's the big


If you've read my previous threads, you'd see we're having a slew of issues but the most recent problems have risen after we had a technician come in for "preventive maintenance", which is now taking on a while new meaning, on our Jv3.

So, down to the reason I'm here again. The technician that we had in originally came back yesterday morning, re-ran tests, calibrations and verified settings, spent hours on the phone with another technician to decide that the print head he originally replaced must be defective.

He returns this morning, new print head, first test print and problem UNSOLVED. Again, after hours of trial and error test prints (ran through a 1/2 roll of material not to mention ink and cleaning solution), re-running calibrations, and spending hours on the phone with another technician... he's gone for the day problem unsolved.

Here's a run down of the ideas that we've eliminated throughout this 2 day adventure:

*He replaced the dampers, capping station and the Cyan print head (twice)
*He's run diagnostics with no errors
*He says all the calibrations are PERFECT
*We've printed everything under the sun to make sure it wasn't a printer issue (printed from both onyx and rasterlink, printed raster and vector based images, printed with different profiles, printed with the profiles off, printed at normal and fast speed, printed 8 pass and 16 pass, printed solid 100% CMYK bars, printed combo of variations of 100% CMYK, printed on different materials, printed uni and bi-directional- there's probably more
*He's switched the print heads, cables and other various components within the carriage.

Now, what is happening... every inch (yes I measured) there's a lighter amount of ink being layed. He's come to the solution (with the suggestions of 2 other techs) that the motor and encoder strip are causing the problem. The motor does make a lot of noise on "fast" print, but always as long as I've been running this printer. The encoder strip does have a few scratches but they are low on the strip where they wouldn't affect the print (he confirmed this with another tech this morning).

I need your thoughts before I proceed. I don't feel that these two elements are the problem, and don't want to dump even more $$ into this without knowing FOR SURE.

 

[NEGD]

forgot to mention, I originally thought that it was only happening with Cyan, but once we started doing test prints we found that it's universal and it happens in a pattern (like I said every 1").

 

[artbot]

was reading over all the past and present threads on this. so currently can you give us an update on the vertical banding and separately the horizontal banding?

and does this last update mean that it's not just light cyan? but all colors are doing the same thing during printing?

 

[Letterbox Mike]

I assume you're printing in 8-pass bidirectional, right? This happens every 8th pass, right? It's a fairly common issue, if I recall some of the original Roland machines using the DX4 head also had the problem. We had it on our JV3, several tech support and tech visits never really solved it. I always just assumed it was a flaw in the DX4 head design, it didn't seem to be related to dampers or ink delivery, we still had the issue even knowing the ink delivery system was performing correctly. We were able to significantly minimize the issue by printing mostly in 4-pass unidirectional. The speed will be the same as 8-pass bidir, but it usually seemed to help (but not entirely eliminate) the issue.

 

[NEGD]

was reading over all the past and present threads on this. so currently can you give us an update on the vertical banding and separately the horizontal banding?

and does this last update mean that it's not just light cyan? but all colors are doing the same thing during printing?

Vertical banding was due to too much heat and the material tunneling, as a few of you suggested. When the tech was here the first time, he mentioned that our heat settings were too high. I had never adjusted them from when I took over because they worked. So shortly after he left, I lowered to suggested temp but apparently it wasn't enough. I had to lower again to get the tunneling to go away, and in turn the vertical banding.

Yes, it's not just the cyan, it was just much more noticeable in the cyan and not the others.

 

[NEGD]

I assume you're printing in 8-pass bidirectional, right? This happens every 8th pass, right? It's a fairly common issue, if I recall some of the original Roland machines using the DX4 head also had the problem. We had it on our JV3, several tech support and tech visits never really solved it. I always just assumed it was a flaw in the DX4 head design, it didn't seem to be related to dampers or ink delivery, we still had the issue even knowing the ink delivery system was performing correctly. We were able to significantly minimize the issue by printing mostly in 4-pass unidirectional. The speed will be the same as 8-pass bidir, but it usually seemed to help (but not entirely eliminate) the issue.

I run MOST of our jobs at an 8 pass, bidirectional as you said. And I would have to think you are correct in saying that it is occurring on the 8th pass since it's about an inch down the material.

We're currently running a job in normal speed, 16 pass and the issue is still there just not so noticeable and much closer together.

When this is finished (is going to take all day for 1 job), I will try a 4 pass uni-direction on the same job and see if this helps. Thanks for the suggestion!

 

[Letterbox Mike]

Is your problem mostly predominant in blues? Ours wasn't too noticeable except when we were printing darker blues or greens. It was there all the time but usually it wasn't too noticeable, except solid blue...

The JV33 (or the DX5 head) has eliminated the issue, for what it's worth...

 

[NEGD]

Is your problem mostly predominant in blues? Ours wasn't too noticeable except when we were printing darker blues or greens. It was there all the time but usually it wasn't too noticeable, except solid blue...

The JV33 (or the DX5 head) has eliminated the issue, for what it's worth...

Yes, it's very noticeable in the Cyan, and the job we're printing is a 60 C 40 M 10 Y 0 K background which makes it SUPER noticeable.

I tried my best to get some better shots from our prints the previous 2 days.

 

[Letterbox Mike]

yup, that's it... Not to be the bearer of bad news, but I've never heard of anyone finding a solution to that. Thinking about it, I wonder if it has anything to do with the ink too? I'm curious if people running non-OEM ink have the problem or if it's isolated to OEM.

 

[Redz Signs Inc.]

3-3-7. Abnormal ink shot​

Problems​

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Vertical lines during plotting, square spots, or plotting out of range.​

Causes​

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1) The head FPC cable is in poor contact.
2) The connector of head has broken. (Metal corrosion)
3) The linear scale is not dirty or damaged.
4) The linear scale position is appropriate.​

Checking procedure​

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1-2) Disconnect the FPC cable and then check the contact surface visually.
3-4) Visually confirm the Linear scale.​

Remedies​

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1) Replace the head FPC cable with a new one.
2) Replace the head with a new one.
3) Replace the linear scale if very damaged.​

4) Adjust the position of the Linear scale.

 

[Rydaddy]

yup, that's it... Not to be the bearer of bad news, but I've never heard of anyone finding a solution to that. Thinking about it, I wonder if it has anything to do with the ink too? I'm curious if people running non-OEM ink have the problem or if it's isolated to OEM.

Battled with this for years. 720 4-pass was our go-to profile with our JV3 for this very reason (color shift on every 8th pass.) I see it on our EPSON even in 720 8pass. Not as often, but I do see it... and typically on 180cv3.

 

[Letterbox Mike]

Battled with this for years. 720 4-pass was our go-to profile with our JV3 for this very reason (color shift on every 8th pass.) I see it on our EPSON even in 720 8pass. Not as often, but I do see it... and typically on 180cv3.

Yup, we see the same thing on our GS6000 in certain solid colors as well at 720x720. Which, btw, isn't a great resolution for the DX5 head anyway, it's much much better at 540x1080. Our JV33 prints marginally well at 720, but put it in 540x1080 and its far far better. I haven't written any 540x1080 profiles for the Epson yet, haven't had time, but I really need to, I think it will drastically improve the print quality.

 

[Rooster]

It seems to me that the number of passes corresponds to the 1" width of the print head.

If a lower number of passes seems to resolve the issue then I'd think it might possibly be a memory issue where some RAM is dropping the instructions for the last pass. I have no idea where the printer stores the information that goes to the head (whether it's the head, slider board, main board, etc.), but a tech might be able to confirm with Mimaki where it's stored and whether it might be the cause of the dreaded last pass dropping out.

It's a long shot, but it would make sense since all the other options have been tried.

 

[NEGD]

thanks everyone for the insight. I'm surprised that if this is such a common issue with the Jv3s that the tech didn't know immediately what the problem was.

I did run a 4pass uni this morning and it looked fine in normal print speed, once I bumped it to fast the issue was very apparent. At least, for the time being, I have a work around until we decide how to proceed from here.