Canon 7000VP Yellow Dots

[mguffin]

Has anyone else noticed that the yellow dots that are on every print from an ImagePress C7000VP are changing the color of the paper? We use McCoy, LOE and Creator, and on some of the papers, the yellow dots are so noticeable, it makes the printing un-sellable. We contacted Canon, and they told us that "No one else ever complained about this".

We had one of the top engineers in to fix the problem. He said that he only saw the paper changing color when the machine has dirty fuser rollers. The machine is 2 weeks old, with less than 5000 prints on it. After taking the machine apart, and scratching his head, he made a few phone calls, and was told that it is the security images that are doing it, and that no one else ever complained. This particular engineer never noticed the issue on any other press he worked on.

My question is, with the color of the paper changing so drastically, and we saw it on the first print out of the machine, is it possible that no one ever complained about it? Does any one else do QC?

 

[ajr]

This pattern is the same on Xerox machines, if you can decode it (the series of dots) it gives the machines serial number therefore the printed work is traceable. Blame the CIA! Google it lots of info on the internet, I thought it was only Xerox machines though.

AjR

 

[mguffin]

This pattern is the same on Xerox machines, if you can decode it (the series of dots) it gives the machines serial number therefore the printed work is traceable. Blame the CIA! Google it lots of info on the internet, I thought it was only Xerox machines though.

AjR

Believe me, I know exactly who to blame...!!! We have an iGen3 and there is no issue. I'm not sure if the iGen does it or not, but if it's there, it doesn't seem to change the look of the white paper...

 

[StrikTenn913]

Hi Mguffin,

I assume you are talking about the yellow dots that are printed as a security feature against counterfeiting? Canon is not the only manufacturer that does this:

Printer dots raise privacy concerns - USATODAY.com

I am very familiar with the imagePRESS and use the model almost everyday. I've printed on a variety of media ranging from 20lb uncoated bond to linen and high gloss cover stock. I have never experienced the color change phenomenon you are mentioning. I have also used Sappi McCoy Matte stock and have only noticed the dots if held up to a light while varying the angle of the print.

Is there any particular commonality in the stocks that you're experiencing a color shift with? (ie. light weight vs heavy, gloss coated vs. uncoated). Also, is there a particular lighting condition you are using when you are comparing a printed sheet to a black sheet?

Please also Direct message me if you have further questions or feedback. I'm from Canon corporate, but may be able to discuss with your supporting dealer.

 

[mguffin]

The paper also seems to be gray, or dirty, not always yellow... Only on the printed side. We are having the problem on gloss, matte, cover, text, bond, 80#, 100#, 120#, 28#...

When the print comes out, if you tear the sheet in half and flip one of the pieces over to the back, you would swear that the two halves are different paper. Does not happen with our iGen3.

Mike

 

[jrsc]

That does not sound like the yellow dot pattern. I think you have something else wrong with your machine, maybe a defective drum or something. I'm not a tech so I don't know for sure, but I've seen problems like this before on other machines and its always a quick fix for the tech. Your tech should be able to figure it out. Get them back in there and make them keep replacing parts until they get it right.

 

[mguffin]

That does not sound like the yellow dot pattern. I think you have something else wrong with your machine, maybe a defective drum or something. I'm not a tech so I don't know for sure, but I've seen problems like this before on other machines and its always a quick fix for the tech. Your tech should be able to figure it out. Get them back in there and make them keep replacing parts until they get it right.

Well, we had 2 techs in on Tuesday, for about 6 hours, and they came to the conclusion, after taking the machine apart and making several phone calls, that it was the security feature of the machine causing the problem. They were pretty sure that it shouldn't be as apparent as it is on our machine, and they would run some tests on other machines and get back to us...

I'll keep the thread updated...

 

[StrikTenn913]

I agree that it appears your issue may be TONER SCATTER opposed to something with the security pattern.

If you have a one of the Fiery-based servers, do you notice a difference when the TONER REDUCTION setting in the image tab is checked on or off?

This is a RIP-side toner limiting feature...

 

[gordo]

If you look at the printed work through a blue filter you might be able to determine whether the yellow dots have an organized pattern (the secret code) or disorganized pattern (i.e. toner scatter) as well as how much of the paper is covered by yellow and hence whether that's sufficient to shift the color of the paper rather than some other cause - like heat.

best, gordon p

My print blog here: Quality In Print
Current topic: The Wayback View – SP Plateless Offset Technology in 2000 (video post)

 

[alf]

You might be having the same problem i had with the Xerox 5000.

http://printplanet.com/forums/digital-printing-discussion/14799-background-issues-xerox-5000-a

It wasnt a yellow security dot issue, it was the fuser fusing the ambient toner/dust floating inside the printer. A full service reduces this by quite a bit, but its definately noticeable on whiter paper.

Security features are usually enabled for color prints only, so you might want to try a single sided black/white print to check on this.

You can take the RIP out of the picture by doing a direct print from the printer unit itself (Usually they have diagnostic single side prints)

 

[StrikTenn913]

Just curious if you had any update with this?

 

[mguffin]

I am being told that the problem is not the yellow security feature, instead, it is the cyan, magenta and black toner dust that is sticking to the paper. It is more of a problem with the gloss stocks. I am also being told that the machine is running correctly, and what I am seeing as just the nature of the machine. The problem is less apparent when running bond, unfortunately, we didn't buy the machine to make copies. The engineer that was here ran a bunch of samples, and is forwarding them to another engineer to get confirmation that the machine is running properly. I'll have another update when I hear back. I am at the point now where I would like to see my stock running on another machine. I am trying to make that happen now.

 

[Craig]

I'll give you an example of their answer.

Canon - the lab said your machine is running at our specifications and is within tolerances.

Customer - What are your specifications and tolerances?

Canon - We do not give that information out.

Customer - So basically as long as it's putting some sort of color on a sheet of paper it is within specifications?

Canon - Yup.

That's a summary of my dialog with Canon 2 years ago.

 

[dave4shamrock]

I haven't seen a problem of this magnitude on the 7000VP and we've put over 1mil clicks on it in 9 months. Mainly coated stocks, from 70# text to 120# cover. What I have seen is a lot of toner speckles along the edges of the sheets caused by all of the loose toner and developer in the press - the same piles that accumulate on the main transport in the print unit and seem to get everywhere.

About 2 weeks ago, one of our techs came out and installed a retrofit kit on the developer units that has eliminated the majority of this mess. It's basically some of that thin plastic that they use in different places like a squeegee (to keep the rollers and drums clean) that covers the left and right edges of the developer rollers. What used to be a daily cleaning ritual for me of vacuuming up those piles is now gone.

If you don't have them installed, check with your service tech. Mine had apparently been waiting to see if they worked on other local units before he put them in here.

 

[GotToner?]

Canon is aware of the issue and the retrofit that dave4shamrock detailed is the fix. Works great! Canon has been VERY responsive to issues with this press. If you feel like they aren't all over an issue that you are having, make certain that your tech is opening a ticket with Canon.

 

[StrikTenn913]

The retrofit being referring to is the 'Side End Sheet Kit' for the developer assemblies. The kit will definitely help with the problem you're encountering, so I'd recommend reaching out to your Tech if this kit hasn't been installed yet.

 

[simpleprint]

That does not sound like the yellow dot pattern. I think you have something else wrong with your machine, maybe a defective drum or something. I'm not a tech so I don't know for sure, but I've seen problems like this before on other machines and its always a quick fix for the tech. Your tech should be able to figure it out. Get them back in there and make them keep replacing parts until they get it right.

Nope. If this is what I think it is, it's not a quick fix...it'll keep coming back after it disappears for a few months.
When the machine was designed, the engineers thought putting the toner/developer units less than six inches away from the primary fuser would be a good idea. Well, this coupled with thin sheets of metal as dividers...that should work, right? Nope.

Well, if you've had or ran an imagePRESS C7000VP considerably (over six months), open it up and pull out the fusers...look at the ceiling inside the machine...see how the coating is melting?
Well, the same thing goes on all around the Fusers not just above it. That Yellow stuff's on your output's affected by heat - obvious, yes...too much heat and not enough ventilation = clumps and dumps coming from the toner/developer unit placed less than six inches away from the Primary Fuser! Round of Applause here...Yellow or Baby Poo Green streaks or dots'll begin to show up on the output media. If you're "lucky" and the heat spreads, you'll get "bad acid trip skidmarks" on your output media and not just dots.

Oh, and for what it's worth...When the edges of your output media begin to fade/go cloudy...adjust your transfer voltage at the console during test runs.