Inexplicable Horizontal Lines: Colour Specific, Multiple Machines

[Onyx]

Hey folks, I have a heck of a problem here, that we are at wits end to try to solve. In a recent lunar new year related project, we had a spot colour orange on a spot colour red, and we got random, sporadic yellow lines in the middle of the orange. (On a Bizhub C1070 running an IC415.) As usual, I first assumed there was a mechanical issue, and cleaned coronas, examined other print jobs, but then noticed the line _only_ shows up in the orange, not the adjacent red spots, isn't in a consistent location across the width of the print, and isn't necessarily the same distance from the start of the orange elements.

We were told it was a file creation issue, not print-side, and running the job on a different make of printer seemed to confirm this. (C5501-IC408)

I tried running it on different paper. Then, we remade the file. Then we remade the file through a different computer. Then it was saved off a different program, and saved through a different format. The only thing that reduced the frequency, but did not entirely eliminate it, was flattening all the spot colours to a .jpeg. At this point it only showed up on 2 sheets out of 71 run. (Acceptable losses for the job we needed to run.)

As part of troubleshooting, and in hopes of isolating the problem, I created a test file of random circles in random spot or process colours, over various spot or process background colours. It even showed up on a green spot, still made to include the equal parts magenta and yellow from before, and could be seen faintly through the cyan toner. It's random, only seemed to show up in a single element type across the entire print page, and changed positions on the page. Everything we thought was dialed in was upended by some other occurrance.

Then came today, and my writing here. We're running a new job. New spot colours, new file, and this time orange over a navy blue background. Different computer, everything...

...And it showed up again. Subtle, but distinctive, and in a few specific locations across the sheet. I'm attaching photos of the problem, in hopes someone else out there has seen this before, and knows any steps or workarounds to fix it.

I'm at wits end. I've exhausted all methods I can think of to change things and adapt them. I've contacted Konica (over a week ago) and had radio silence.

On the photos, the arrow indicates lead edge leaving the printer.

Please help me Copytechnet folks, you're my only hope!

[Synthohol]

why dont you just run the 11x17 halftone test patterns and look at each color by itself?
on first glance it looks like a dirty magenta corona issue but i would run the halftones in svc mode and see exactly whats going on. swaq corona units around is my first process of elimination.
good luck! let us know.

[blackcat4866]

why dont you just run the 11x17 halftone test patterns and look at each color by itself?
on first glance it looks like a dirty magenta corona issue but i would run the halftones in svc mode and see exactly whats going on. swaq corona units around is my first process of elimination.
good luck! let us know.

I'm going to disagree Synthohol. The anomaly appears at the leading edge of the appearance of the orange element ... not at a specific interval, but at the start of the appearance of the specific orange color. Clearly it's the absence of magenta crossfeed, but I agree that it's occurring in the composition of the electronic original, or it's conversion through Fiery WorkStation.

Since it seems to affect a range of shades of orange, perhaps there is some corruption of the reference colors in the Fiery software? I don't know enough about the Fiery software to offer a course of action.

And you're sure that shades of magenta and red remain unaffected? If yes, then it's definitely not a printer issue, it's the conversion to print data.

I would be interested to see how this image prints:
=^..^=

[Synthohol]

wait, the arrows are the feed direction? if so i totally misread the prints.

[K-3]

if file printed fine from a different fiery controller then i would assume that your ic415 has some type of corruption of file or internal software, try to reload fiery system software and patches or find a used fiery (ic415) and try that, i don't see it as a mechanical issue as it is too random and only effect that color. long shot could be image processing board on copier. good luck.

[Albonline]

i would try running the job on a real firey , not one of the small ones , see if it still happens.

[Onyx]

@Synthohol: Yeah, I'm never 100% certain how to describe that; Arrows show the leading edge as it'll come out of the printer. The lines are horizontal, which is what made me first suspect a drum or belt issue until I noticed it's not on the reds.

@K-3: I flipped it to an IC408 as well and it still showed up there.

@Albonline: sorry, I'm not quite certain what you mean, can you please clarify?

I have an update from yesterday: It ran without flaw ~250 times when we converted the image and overlaying orange to a single background layer of .jpeg, with the rest of the text on it. I suspect it has to be something with how Fiery is processing spot colours, for putting it on JPEG to fix it. (That was done last time as well, though, and only mostly fixed the problem.)

My fear is that we're going to have to update the fiery, but that'll write off our C5505, since the newest fiery controller isn't compatible with the new editions, as far as I understand.

Thanks for the swift aid folks! IF I can figure out a fix (or hear back from Konica directly) rest assured I'll post it on here!

[Albonline]

@Synthohol: Yeah, I'm never 100% certain how to describe that; Arrows show the leading edge as it'll come out of the printer. The lines are horizontal, which is what made me first suspect a drum or belt issue until I noticed it's not on the reds.

@K-3: I flipped it to an IC408 as well and it still showed up there.

@Albonline: sorry, I'm not quite certain what you mean, can you please clarify?

I have an update from yesterday: It ran without flaw ~250 times when we converted the image and overlaying orange to a single background layer of .jpeg, with the rest of the text on it. I suspect it has to be something with how Fiery is processing spot colours, for putting it on JPEG to fix it. (That was done last time as well, though, and only mostly fixed the problem.)

My fear is that we're going to have to update the fiery, but that'll write off our C5505, since the newest fiery controller isn't compatible with the new editions, as far as I understand.

Thanks for the swift aid folks! IF I can figure out a fix (or hear back from Konica directly) rest assured I'll post it on here!

a non e firey, one that sits on the floor, not hanging on the back.

[Onyx]

Ah, gotcha. Unfortunately I have no access to one of those. Hopefully the test file I sent to folks at KM will be tested on whatever variety of machines they have for testing and I'll get one done on a floor machine.

[allan]

Half-tones please. Just to eliminate an engine problem.