Copystar 650c prints with light/white spots on single color channel prints

[Guest]

Hello, my school has a Copystar 650c that has been a problem child since it's installation. We have replaced all of the developers due to problems with spots showing up on the prints where the color was not bonding properly to the paper. I have been using a test document that prints a full page in each primary color, cyan, magenta, yellow and Black.

The prints show patches where the color does not bond to the paper evenly, leaving white or light patches in what should be even, solid color. We have had the same problem on all four color channels, and over the last several months replace all four developers.

After replacing the last of the developers the print quality seemed normal for several weeks, but we are now seeing the same issue on the cyan channel again now, after only about 3/4 of a cyan toner cartridge was printed through it.

Our printer service company asked us to change the toner out before it was completely empty, (like at 20% low toner warning which seems both wasteful and ridiculous) but the light spots showed up again before the low toner indicator even tripped off. So my gut tells me there is something else going on. I swapped to a new cyan toner anyway even though the old one seemed to have 25-30% left. Prints seem slightly better, but not normal.

Is there something that could be killing the developers off in less than two months?

[Jules Winfield]

Are you using OEM toner or some off brand? Generic toner kills copiers, especially color machines. Also check how you are storing your paper. Too much humidity in paper will cause light spots as well.

[kyocera.team]

try to print some du[lex side and check the quality for each side

[am@school]

Thanks for the suggestions guys, toner is 100% genuine and fresh stock. Same results regardless of paper stock, tested on everything from standard copier grade letter up to 160$ a box 12"x18" A3+ tabular proof paper. I will run Duplex prints and post results. I didn't think that the developers were 2 sided, or do you suspect that something is rubbing it off in the duplexer?

[am@school]

Ok, on your suggestion I have run off duplex copies of the full page Cyan test sheet. The problem appears on both sides, but on one side appeared faintly, almost unnoticeable. The other side had more pronounced spots. They appear to track with the position of a roller or drum, which seems consistent with the construction of the developers. It also seemed more pronounced on the large format 12x18" a3+ proof paper they use. It is a high quality semi-gloss finish paper, like magazine paper. I have a service call with out for the machine today so I will post any new information that comes out of it.

[Jules Winfield]

I would get as much information as you can on their paper (see if they'll let you look at the wrapper) and compare it to the specs that are listed in the service manual or user's guide to see if the paper is within the allowable range. I highly doubt it if it is anything like magazine paper. I can see why you're having problems...

[blackcat4866]

kyocera.team is suggesting that its a moisture problem with the paper. When the first side is being fused, the heat dries the paper so that the second side comes out much better.

From a technical viewpoint it takes more transfer current to transfer the image to "moist" paper than it does to transfer to "dry" paper. Moist paper is usually an environmental issue. If the paper is stored cold (like an unheated warehouse), then immediately loaded cold to the tray, you could see this affect. If it's very humid in your office any unwrapped paper will absorb the moisture.

That's the ultimate test (duplex copying). =^..^=

[am@school]

Paper

Interesting, I would never have guessed humidity, but it does make some sense. I could mark out the sides and confirm if the second side is clearer. I will also post specifics on the paper. I know they have been printing on 12"x18" paper from xerox (28lbs) and some lower spec 20 lbs stuff from another manufacturer, as well as the same great white letter that we run through by the palate. Most of the large format paper has been stored in a cabinet in the office for some time, the standard letter may have been stored under more exposed conditions in the basement. While it is California, we have had higher humidity the last few days.

[am@school]

Ok, we had a technician out again yesterday.

He described the color density issue as "feathering" as opposed to streaks or spots. He also tried initially to blame the paper but it didn't pan out. The paper is Xerox Color Xpessions Elite 12"x18" 28lbs weight, it has been stored at room temperature in an interior cabinet that is bone dry. The regular letter paper is fresh stock as well, 20lbs and while I was initially afraid it might have been stored in the basement, it never was. It is in a dry storage closet and is not damp. Additionally the exact same letter stock prints fine from our 400ci. The lower grade 20lb large format paper was actually 11"x17" and is not being used currently in the 650c. (it is used in the 400ci, and also prints fine!)

Also, this is only effecting ONE of the four color channels. A paper humidity problem wouldn't only hit one primary color right? Magenta, Yellow, and Black print fine on both passes.

His current theory is that the problem may due to how the Fiery RIP is interpreting the color, and suggested re-calibrating it. We will do that but that idea also seems questionable, as the problem went away after replacing the developers, at least for a while. We replaced each of the four color developers, one at a time, and each time that fixed the fathering for the color that was replaced. Unless the Fiery is trashing the developers due to some configuration issue, I'm not sure how that would effect it.

[blackcat4866]

Yes it sounds like you've ruled out the paper. But it doesn't make any sense, that the Fiery configuration could do anything to the developer. The developer density (toner versus developer ratio) is maintained by the logic board on the machine, not anything to do with the Fiery. The Fiery only manipulates the image electronically.

As Jules suggested, developer density can be thrown off by the use generic or aftermarket toner. But you say that it's OEM toner. Right now this explanation makes the most sense, especially if a developer change restores the image quality, but it would affect both sides of the paper equally.

When you duplex, are you copying both sides in the same operation (1 to 2 sided or 2 to 2 sided), or are you copying a single side then reloading the paper to the tray and copying the second side? There's a difference, and it's important. When you duplex in one operation (as it's designed to do), the machine is capable of adjusting the transfer current to accommodate the second side copying. Sorry if I'm getting too technical.

Some machines can have the transfer current adjusted separately for one sided copying, then a different value for the second side. I don't know if your machine operates this way, but very likely. One of these values may have been changed at some point. =^..^=

[am@school]

Thanks Blackcat, and my duplex test was run as follows:

From Excel for Mac 2011 I created a full page spread sheet and filled the cells with a custom color (colorspace CMYK, set 100% cyan). I pasted the Letter size sheet to a second page and printed the job using the printers duplex option.

It printed both sides automatically. The feathering issue was more pronounced on one side.