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Russell H.
Russell H., Printer and Office Tech
Category: Printers
Satisfied Customers: 9296
Experience:  11+ yrs experience, inkjets & lasers, from huge to portable
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My Canon MF5700 has started printing a black line down the

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My Canon MF5700 has started printing a black line down the left side of pages. What is the problem and how can I fix it?

Hi, thank you for contacting My name is Russell. I will do my best to provide the right answer to your question.

There are several causes for a black line down all pages printed from a laser-type printer like yours. I am assuming in the following that the line is invariant in size and position, and that it runs down the full length (the longer dimension) of each and every page.

One is, damage to the fuser roller. The fuser is the heated part, with 2 or 3 rollers in it (one metal and very hot, one rubber and fairly hot and often red in color, and sometimes a third) at the end of the path the paper takes through the printer. (The paper emerges in a heated state, because it has passed through the heated fuser.)

The second is, a dirty corona wire. It can be cleaned, usually by taking out the toner cartridge, and locating a colored plastic handle on it, then sliding that handle back and forth over the entire width of the toner cartridge, several times.

The third is, a defective toner cartridge - sometimes.

The fourth is, a damaged photosensitive 'drum'/roller.

Check the second possibility first. Then the third is most likely - unless you have already tried changing the cartridge and it hasn't relieved nor changed the problem.

The fuser should be checked on - with caution. Turn the machine Off and leave it for 10 minutes, to let the fuser cool off enough to be safe to touch. Then open the machine (after cooling 10 minutes) and locate the fuser, next to the exit from the machine's paper path. Open the fuser (which often has a cover over it, usually covered with felted material to insulate the touch against burns) and examine the rollers. A 'stripe' down each page would mean a scraped-off area on the fuser roller(s), which would be evident to the sight, and might look like a black stripe in corresponding position, on the fuser roller.

The photosensitive 'drum' is often included in the cartridge, and is difficult to check, but is mentionable. If it comes down to 'the drum may be damaged', then we can go into that problem in more detail when you reply to me about what you have found out. Let me know. Thanks.

- If there is anything lacking in this answer, please " Reply " letting me know, and I will try to improve upon my answer.
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Russell H. and 4 other Printers Specialists are ready to help you
Customer: replied 3 years ago.

I have to leave right now before I can check out your answers. I will not be able to do this until Monday morning. Is that OK?

Monday will be fine. Let me know what you find out then.
Customer: replied 3 years ago.

Thank you for understanding. It's my granddaughters' birthday celebration.

Enjoy it, and tomorrow's time enough. No need to reply to this until then. Your question/case will remain open just fine for the interval, I think.
Customer: replied 3 years ago.

Good Morning, Russell,

This is Bea. I had to leave last night before I could check out your answers to my question about the black line on the left side of my copies. I changed the cartridge and there were no black lines. I then re-inserted the original cartridge and the line disappeared almost entirely when I did a manual feed (just a very very narrow black on the left bottom 2 inches) BUT was still present when I printed from the automatic feed tray.

So It must be the defective toner cartridge, unless you think there is something else going on.



It is very good to hear back from you.

The difference (in your perceptive tests of the situation) between the manual feed print and the automatic feed tray print, is one in position of the paper when it passes the cartridge, no doubt. Toner that would be deposited heavily in one case misses the paper a bit in the other, you might say.

If the new toner cartridge fails to produce black lines, then yes, there was probably a fault in the toner cartridge. If the faulty cartridge was fairly new in the printer, then it might be returnable, as defective, to the supplier.

Thank you for making good use of the advisory resources of Please rate my Answer (hopefully favorably) so that I may be paid for the work I have done on this case.)
Customer: replied 3 years ago.

You have been very helpful and thorough. Thank you.