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New Contributor
Posts: 1
Registered: ‎07-12-2017

MG6821 PGBK Print Nozzle Problem

I have a one month new MG6821 printer. The printer works fine in the beginning, until today all black printouts have double lines. I ran print head clean and deep clean, doesn't help. I have also ran print nozzle check pattern, please see below photo. Does anything know whats going on?


New Contributor
Posts: 1
Registered: ‎09-24-2017

Re: MG6821 PGBK Print Nozzle Problem

I have the same problem on my MG7150 which is a few years old now.

My page count is up to 8401-8450.

I suspect this is a fault with the PGI part of the print head.

My printer is well outside warranty so was about to bin it and buy a new one but I have found a workaround.

It only affects the PGI black which is the normal black used for text.

I have set my print preferences to always print in 'Photo' mode by default.

My prints are now all fine.

OK I know I have just bypassed the PGI tank but this is OK for me as my prints are now sharp.

I also refill my cartridges and for a while now I have put dye based ink into both black tanks anyway.

I did originally refill the PGI tank with pigment black but stopped buying two types of black for convenience a while back and I really can't tell the difference anyway.

With your printer being so young, I would just return it (I suspect you already have!!).


I thought the problem may be a print head indexing problem but since my printer is fine now I have set it to 'Photo' only, I suspect it is a fault with the nozzle timing for the PGI part of the print head. I suspect a new print head will be as much as a new printer so I will run my printer in 'Photo' mode and see how long it lasts.

Product Expert
Posts: 2,722
Registered: ‎10-16-2012

Re: MG6821 PGBK Print Nozzle Problem



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New Contributor
Posts: 1
Registered: ‎01-31-2018

Re: MG6821 PGBK Print Nozzle Problem

I am having exactly same issue.  I have seen enough posts around internet with same PGBK print head issue across the Canon range of printers, so I am fairlz y certain this is not an isolated problem to one model. .  I tried cleaning and deep cleaning the print head but that failed to resolve issue.  I tried removing print head and cleaning with Windex... that improved print quality slightly but did not solve the issue with the PGBK print head.  I made a hard reset of the printer to see if that helped... no improvement.   In the end I now decided to set the default print for Glossy Paper to trick the printer into photo printing and bypassing the PGBK cartridge.  The print quality is really fantastic but I am not solving the issue with the PGBK print head.. This is my second Canon printer its 3 yrs old the first one lasted 5 yrs.  I am not sure if its a built in failure mode but I am not impressed.  I am reading stories that Canon have a built in failure if the printer detects aftermarket inks (which I do) .. thats seems to be a growing urban myth however I see no reason why good quality aftermarket inks should have a problem and I have used good quality aftermarket inks since I purchased the printer.. so why fail after 3 yrs.


I am not sure if it is worth to replace the print head...  I am not sure if it will fix the problem.   I would certainly welcome any advice from Canon representative.  If I replace the print head am I throwing good money down the drain??

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