Double lines in nozzle check

Any suggestions what is causing the fine double vertical lines in the PGBK grid in the attached nozzle check for a Canon MX925?

Edit: the PDF I attached bears no resemblance to the file I uploaded, which does not have broken lines. I'll have to get a better image somehow.
Better PDF attached. The colour checks are wrong, but you can see the lines in the PGBK

Sadly the nozzle check shows a print head damage in pigment black. Only a new print head will make the printer OK again. A new print head is found at CRC Tasktron UK.

The damage is probablty caused by overheating due to the use of unsuitable refill ink and/or cartridges. See this thread about a similar problem.

PeterBJ said:

Sadly the nozzle check shows a print head damage in pigment black. Only a new print head will make the printer OK again. A new print head is found at CRC Tasktron UK.

The damage is probablty caused by overheating due to the use of unsuitable refill ink and/or cartridges. See this thread about a similar problem.

Click to expand...

Thanks for finding this thread. It's really bad news. I just bought a new print head from Tasktron for my other MX925 last week. There had been continual problems with the compatible cartridges used in the other printer, so I was not too surprised I had to replace the print head there. But I've had no problems so far with the cartridges on this printer. They were from a different manufacturer from those used on the other printer. I got all of them from Octoinkjet, and Martin has now switched back to using OEM cartridges instead.

I think the print head price at Tasktron is good at the moment. On the other hand I don't use this printer for photos, and it actually prints OK for my purposes at the moment, so I'm not sure whether to replace or not.

Any thoughts on whether the pigment problem is likely to get worse?

I have tested a set of PGI-550/CLI-551 refillable cartridges with ARC chips in an MG5550. I have experienced both ink starvation and ink leaking from the cartridges, and the chips came out of sync with the ink level in the cartridges.

I am sure the combination of OEM cartridges and a resetter is much better for refill, but I have not tested refilling OEM cartridges as a set of used XL cartridges plus a resetter is more expensive than the value of my MG5550.

My MG550 has not developed problems with the pigment black. Instead it has developed a similar problem with dye (photo) black. This also seems to be a common weakness for the printers of the PGI-x50/CLI-x51 cartridge generation and probably also the PGI-x70/CLI-x71 cartridge generation.

Compatible/refillable cartridges vary very much in quality, and price and quality do not always match.

I don't know if the PGBK error will get worse, but if it was caused by overheating, and you are now using better inks and OEM cartridges, it might probably not worsen.