Canon I-sensys MF8540CDn - calibration problems

[xbase]

The machine gone away, I can not try it . But thank you for your help.

Ah, it was a question for an expert rather than a suggestion, I hope someone can answer soon! Anyway I have found some cheap but genuine canon toner so I will try using OEM cartridge first, I hope it will fix it.

[xbase]

OK, so genuine canon toner cartridges installed.

At first the print-out is reasonable, not perfect. But as soon as the machine auto-corrects (exhibited by 'Correcting...' on the screen after a print) then the colors get seriously displaced again (vertically) by about 3mm. Trying a manual color mismatch correction fails. It fails a little quicker than before.

Any suggestions why color mismatch correction is making things worse?

[xbase]

Wow, finally after months of struggle, I have corrected the color mismatch!!

The problem was after doing the COPIER-FUNCTION-CLEAR-ALL - all the settings for the laser scanner unit are cleared.

Unhelpfully there was no label stuck on the inside of the right panel as suggested by the service manual. And the process for removing the laser scanner unit in the low chance that the settings are written on the unit itself was too much of a gamble.

But... finally made some sense of the service manual through posts on other forum threads that:

MAI - means horizontal
SUB - means vertical i.e as paper is fed through

So manually adjusting for the direction in which the cyan and magenta colors were being displaced (for me in the SUB direction), I was able to get the colors close enough together for the printer's color mismatch correction function to actually work.

[spree]

I have here another machine - same problem (OEM toners and calibration problems). Yes, inside with right cover down, there was no label with laser parameters. What to do now? I manualy set this horizontal and vertical laser parameters (I set it randomly with values marginal + and marginal -) and it is working!