ip8720 printer only prints Word docs (or text anyway); prints blanks otherwise

[BLAH]

If it's because I ran out of "bk" ink and only have a full  cartridge of "pgbk," then the printer should tell me that instead of just not working!  This is by far the worst printer I ever bought and I am in disbelief that the company thinks it can sell this stuff! Everything is bad about it from how long it takes to warm up to how uninformative it is when something doesn't work to the ink I got on my finger just trying to change a simple cartridge.  This printer is so bad I rarely use it, using an ancient printer I had with an older computer instead, and yet finally managed to run out of "bk" ink.  Then where is the option to temporarily use "pgbk" instead of having to buy a "bk" cartridge just to print a 2x2-inch picture?  Okay, I'm going to the store to buy an ink cartridge because I need to print this today, in the hope that it will work.

[jrhoffman75]

PGBK ink is pigment black ink and is used to print text. Pigment ink is solid particles suspended in a liquid carrier.

BK ink is dye ink and is used to print non-text documents in concert with the cyan, magenta and yellow inks. Dye inks are basically colored liquids. Those four inks are blended in various ratios to print all the colors that the printer can print. You cannot mix the three remaining dye inks and black pigment ink - all you would get is a mix of three colors plus black particles.

The Canon BubbleJet technology uses heat to "boil" the inks and force them out of the print head. The ink cools the head. Printing without ink will damage/ruin the print head. That is why the printer won't print if inks have run out.

[BLAH]

Thanks for putting in the time to respond to my message!  Canon should try that too to keep a customer!  It would be so easy for the software to give a message, "Cannot print images until BK cartridge is replaced."  Instead it just spat out blank pages so I had to spend a lot of time figuring out a solution while calls to Canon gave me only recordings followed by being cut off and no help.

[jrhoffman75]

Interesting. My two printers give a message that the ink has run out and also give a message that ink is running low and prepare a cartridge. 

Are you on Mac or Windows? If Mac are you running the Canon driver or Apple AirPrint driver?