I have an oki microline 421 printer. Print is very light even when I put in a new ribbon.

have you tried cleaning printhead easy two screw comes out ribbon cable off soak in isopropenol will clean jets out

Re-install the printer ribbon. It's probably slipping or dragging on the head mechanism, and the printer synchronization control is slowing everything down to compensate.

There is now ink in the machine. You just have to replace the print ribbon. This is the small black box that is mounted to the printhead.

Make sure that you have a good ribbon installed and that the ribbon is advancing as the carriage moves. If the ribbon is not advancing it will only print until the ink has been used up on the section of ribbon stuck in front of the print head. It will also need a new carriage if the ribbon is not advancing.

There is a thin ribbon connected from the printer to the print head. Remove it and re-insert in again. If the end of the ribbon looks dirty, you can use the pencil eraser to clean (erase) it.

If I remember the 320, there is a head-gap adjustment that is normally moved for replacement of the head and must be reset again. Check your manual for that term; 'Head gap adjustment'

Try to perform an offline test print using your printer alone
To do this, power off your printer first
Press and hold the LF/FF button on the printer panel then power on. The printer will perform its own printing ( lines of pattern )
If it does it without problems ( no MENU lights came on ) the printer should be OK. If not try replacing the printer main control board.

Hope this helps

KM Hoo
It

Hi. Could you please grade the phone support I gave yo.

Thanks

If it is not the ribbon, you may have to replace the print head.

Genuine Okidata Print Head

Mfr Part #: 50063802

Hope that helps...

you are correct, you need a new print head OR adjust the head gap on the carriage