HP Latex 330 printed size too small?

[derekw13029]

Hello all,

So I've been running a Latex 330 for over a year now, and today something new has occurred. I'm printing on canvas, with a 20 pass profile I have used basically since I've had the printer. However, my prints are coming out a little bit small in all dimensions.

As I understand it, this shouldn't be a substrate advance issue, because that shouldn't affect the width of my print. I can't seem to think of anything that could cause this, nor have I found anything in that manual that might resolve this issue.

I printed several 72'' x 36'' prints, and the length is off by almost exactly 1/4'' and the width off by 1/8''. While this isn't a HUGE deal, it does affect stretching if I have something that I need to be super accurate on (like prints with borders where the wrap begins).

I have printed some smaller tests, and they are also too small, albeit by a smaller amount. So it seems to be something that is happening as the print moves on, because larger prints are off by a larger amount. But again, the width is off.....

Thanks for anyone with any ideas.

 

[derekw13029]

So, I got all the canvases stretched. The most any of them were off was by 1/2'' on the length.

I'm still not sure what the issue would be. I didn't get a skew warning, and my skew acceptance is as tight as it usually is.

The only thing that makes any sense to me would be the skew, since the problem DID get worse further down the roll. The first couple of prints were right on, but 20 feet later, the print would come out 1/2'' short. And the width was off, which makes even less sense to me.

The 330 doesn't have the OMAS, I ran a substrate advance test, all green. So I'm kind of at a loss for this one.

Haven't tried another substrate because I don't want to waste 20+ feet of material as a test. But when the next vinyl wallcovering job comes in, if my drops are off this could be a serious issue.....

 

[a77]

Canvas does shrink on my aqueous machine (Canon ipf). Usually only in the feed direction. I ended up measuring multiple readings and averaging the shrink. I extend the image to compensate in photoshop and come out near perfect. If you are doing the "mirrored" edge look on your canvas, this is critical. If your design "bleeds" around the edges, and it doesn't matter, then I would just oversize the prints slightly to accomodate the shrink, if that's what's happening.

 

[derekw13029]

Canvas does shrink on my aqueous machine (Canon ipf). Usually only in the feed direction. I ended up measuring multiple readings and averaging the shrink. I extend the image to compensate in photoshop and come out near perfect. If you are doing the "mirrored" edge look on your canvas, this is critical. If your design "bleeds" around the edges, and it doesn't matter, then I would just oversize the prints slightly to accomodate the shrink, if that's what's happening.

I was thinking of doing that, but like I said, the images aren't all too small, just later on down the roll. So if I'm tiling say, 4 or 5 of these guys, I'd have to enlarge each one by a constantly changing amount, then make sure to tile them in the correct order according to how much I enlarged them by. And even then, I'd still be somewhat guessing as to what exact amount of change I needed, though I will say so far they have "shrank" by a standard interval.

But I've ran dozens of rolls of this canvas, tiled job with far more linear footage than this. Never had this issue before. If it is the canvas shrinking, this is certainly something new. Thanks for the info.

 

[Morkel]

I was thinking of doing that, but like I said, the images aren't all too small, just later on down the roll. So if I'm tiling say, 4 or 5 of these guys, I'd have to enlarge each one by a constantly changing amount, then make sure to tile them in the correct order according to how much I enlarged them by. And even then, I'd still be somewhat guessing as to what exact amount of change I needed, though I will say so far they have "shrank" by a standard interval.

But I've ran dozens of rolls of this canvas, tiled job with far more linear footage than this. Never had this issue before. If it is the canvas shrinking, this is certainly something new. Thanks for the info.

Something to consider: Our 360 all of a sudden started doing weird things like skewing and misalignment on successive printing passes. I've narrowed it down to a glitch that happens when the printer has gone in to sleep mode. There is no explanation for it, and like I said, it just started doing it one day and has ever since. So if our printer has gone in to sleep mode, we restart it before printing again. We have not had a single problem since while doing the restart process - in fact we've only had the problem once recently, and it was because I was away and the other guy forgot to restart it.

So is there a chance that some were printed when the printer was fresh, and some were printed after it had been idle for a while and gone in to standby mode?

 

[derekw13029]

Something to consider: Our 360 all of a sudden started doing weird things like skewing and misalignment on successive printing passes. I've narrowed it down to a glitch that happens when the printer has gone in to sleep mode. There is no explanation for it, and like I said, it just started doing it one day and has ever since. So if our printer has gone in to sleep mode, we restart it before printing again. We have not had a single problem since while doing the restart process - in fact we've only had the problem once recently, and it was because I was away and the other guy forgot to restart it.

So is there a chance that some were printed when the printer was fresh, and some were printed after it had been idle for a while and gone in to standby mode?

Hmm, well I tried that yesterday and it would seem my print still came out about 1/4'' short on a 76'' print. Do you turn the power off in the back, as well? I just held the power button until it shut off, then just turned it back on. I'm not sure if that actually does a full restart, however.

 

[Morkel]

Hmm, well I tried that yesterday and it would seem my print still came out about 1/4'' short on a 76'' print. Do you turn the power off in the back, as well? I just held the power button until it shut off, then just turned it back on. I'm not sure if that actually does a full restart, however.

Yeah just a restart on the machine (no need to turn it off at the wall). Was the width correct this time? The length discrepancy is about what you'd expect, just a matter of whether it's a consistent length (ie, tiles of the same size all line up, albeit slightly short).

 

[jawdavis]

Morkel, I'm curious about this process. We've had intermittent issues with misaligning of wallpaper panels, most of which we feel we've solved, but it seems due to environmental factors we still have the occasional misaligned panels. I'm wondering what is happening when the machine goes to sleep that is causing this issue? Are you on the most recent firmware?

 

[Morkel]

Morkel, I'm curious about this process. We've had intermittent issues with misaligning of wallpaper panels, most of which we feel we've solved, but it seems due to environmental factors we still have the occasional misaligned panels. I'm wondering what is happening when the machine goes to sleep that is causing this issue? Are you on the most recent firmware?

Absolutely no idea what's causing it sorry. Latest firmware, everything is up to date. the HP tech did a "file system" purge or rebuild or something that sounds to me like a combined disk cleanup & defrag. Hasn't fixed it. When I'm back in the workshop I'll post some pics of just how bad the skew and distortion ends up. I know that the feed roller is one unit that must turn the same rate on one edge as the other, so how the print twists I just don't know. Not sure if I posted it in this thread or the Colour Consistency one, but on one print that should have been 1600mm long, one side was ~1590mm, the other ~1560mm. That's some serious twisting.