Printing text, about 20% of horizontal lines missing sometimes completely, sometimes missing top half, sometimes bottom half of line. Seems to have started after new black cartridge inserted - E711/891

Hello,
one idea is that you rouined printhead with tap water and second idea is to buy new print head or printer.
Note: If you want to replace ink head, be sure to replace purge unit and ink absorber also.

clean cartridge and cartridge contacts with pencil eraser

pull out the black cartridge then get a tissue paper try pressing the nozzle again the tissue paper but not so hard then release look for the straight line that appear on the tissue paper if it is not change it

First try to copy and if copy works fine, means the hardware is fine and issue with the driver.
Do right-click on printer icon and select delete.
Once deleted, run the installation disc and click on add a device, follow onscreen instructions to complete the installation. Open printers and faxes window and then do right click on printer icon and select properties, click on print test page.
Check if it prints fine, if yes try to print from other application. I hope it will work.

you have a defective or near empty toner cartridge. Try shaking it side to side

there was a problem in u r ink check the cartage,

so, what sort of text is it you are attempting to print? what program is in use?

Considering that the problem lessens further down the page, you most likely have a printhead that may be leaking (oozing) ink.
Once the surplus is wiped off on your paper, the ink flow is OK and the leak too slow to continue making the unwanted lines..

Try printing blank documents, you will probably see the lines with or without text printing.

I'm not certain how the printhead can be removed for inspection on that machine but it may need replacement.

First clean the cartridge and then go to toolbox and give test print.

Run the cleaning cycle. If that doesn't work, try to use an alcohol soaked swab on the print head. Some of the jets are clogged.