Cause for repeating black spot?

[Phil B.]

Thanks Phil.

I haven't found that repeating defect guide in the service manual. But knowing it is there is good, I'll keep looking. I've done a search on the PDF for repepating and for defect. I figured that would work, but no luck yet.

Thanks for the advice on uploading images, I'll check that out.

I checked out the drum last night and it is actually a wear mark / scratch. No amount of rubbing on the drum was taking it off. I could feel it in the drum surface.

I didn't have time to check the counts, it was already really late when I was able to get to the machine and all concerned were in a hurry to do the absolute minimum and head out.

Yes the drums and toner are for sure genuine, gotten direct from Canon.

The plan is that I put in a new black drum tonight.

ok if there is a mark on the drum, is it in the same spot as the defect on the page? YES replace the drum unit in question. Is the mark on the end of the drum out of paper path?

[bret@cos.flag.org]

Roll the paper until the spots match and that's the size of the part that is causing the marks

fuser roller drum etc.......

Old school trick

Thanks. When I got inside the machine it was pretty obvious that it's the black drum. I'm getting a new one and will replace it, hopefully tonight. See photos that I just managed to upload.

[Phil B.]

Attachment 49050

Attachment 49051

Hopefully I didn't reduce the images too much!

yup replace the drum unit...

as far as the question about organic drums... yes there are several type of non organic drums.... they are usually in higher speed/production models that can go 600k - 1mil pages. selenium drums required 'polishing' with a special powder and they could produce a poison (arsenic?) in the sludge removed from the polishing procedure ... organic drum are more for the lower end machines.

[bret@cos.flag.org]

ok if there is a mark on the drum, is it in the same spot as the defect on the page? YES replace the drum unit in question. Is the mark on the end of the drum out of paper path?

Yes the mark on the drum matches up with the location on the paper (on the edge of the sheet) so that pretty much confirms the drum and that wear spot/scratch on it is causing the print defect.

Luckily if I rotate the paper so it is LTR-R, the spot is then out of the paper path and prints look good. That's the temporary work-around for this.

[bret@cos.flag.org]

yup replace the drum unit...

as far as the question about organic drums... yes there are several type of non organic drums.... they are usually in higher speed/production models that can go 600k - 1mil pages. selenium drums required 'polishing' with a special powder and they could produce a poison (arsenic?) in the sludge removed from the polishing procedure ... organic drum are more for the lower end machines.

Wow, I had no idea there were such advanced (dangerous?) drums. Glad to know we have organic drums.

[blackcat4866]

...
Good to know the circumference of a drum. Why do you say "organic drum"? Are there non-organic drums?

When I first started doing this there were Selenium Tellurium drums, Arsenic TriSelenide drums, and Cadmium drums. Then came Organic drums and Silicon drums, and that's mostly all that you'll see now.

I remember hearing about somebody who died of Selenium poisioning that worked in one of the drum manufacturing facilities. But it was incredibly unlikely that a tech could get a lethal dose of Selenium just installing drums.
=^..^=

[tsbservice]

ok if there is a mark on the drum, is it in the same spot as the defect on the page? YES replace the drum unit in question. Is the mark on the end of the drum out of paper path?

Those are repeative you know. I like to print it on A3 paper and measure the distance then divide the result by 3.14. Then measure/compare some more diameters
Often drums and heat rollers have very similar circumference so precision is important just rolling paper and comparing with cylinder inside machine isn't enough.

[slimslob]

When I first started doing this there were Selenium Tellurium drums, Arsenic TriSelenide drums, and Cadmium drums. Then came Organic drums and Silicon drums, and that's mostly all that you'll see now.

I remember hearing about somebody who died of Selenium poisioning that worked in one of the drum manufacturing facilities. But it was incredibly unlikely that a tech could get a lethal dose of Selenium just installing drums.
=^..^=

The problem came in when someone the wrong polishing compound on the Arsenic TriSelenide drums. It could release arsenic gas, the most dangerous form of arsenic.

[Phil B.]

Those are repeative you know. I like to print it on A3 paper and measure the distance then divide the result by 3.14. Then measure/compare some more diameters
Often drums and heat rollers have very similar circumference so precision is important just rolling paper and comparing with cylinder inside machine isn't enough.

Yeah a while back the rollers were different sizes. So the rolled paper trick could be used pretty well.
But in today's time that trick is out the window.

Sent from my SM-G960U using Tapatalk

[bret@cos.flag.org]

Ok, I changed out the black drum, and the repeating black spot went away. I ran color calibrations last night and all was well.

Now today the users are saying the colors are not properly aligned. They're trying to run the Auto Correct Color mismatch and it is saying that it was cancelled and to try running it again, and if that fails to call Support. So they're calling me.

Any ideas what might cause that to fail? Obviously it could be something to do with the drum just installed, but would I need to go back there and open up the machine again? If so any recommendations as to what to look for? All seemed fine when I left it yesterday.

Thanks.