I want to print photos with MK922 it used up small black cartridge but not the large black cartridge

[CFP]

My canon pixma MX922 has a small black cartridge and a larger one.  It is a new printer and I put in the starter ink.  Since I am using it for photos primarily, I bought a pack that came with photo paper, CMYK and a large black cartridge.  I put all of these in and left the starter small black cartridge in.  It has used all of this and none of the large black.  If I take it out, it doesn't work.  I don't understand what the purpose of the large one is, if it is not used and now I won't have any black since the set didn't come with it.

[Patrick]

Hi CFP,

The bigger black ink tank contains pigment based black ink.  This ink provides dark and sharp black text on plain paper.  The bigger black ink tank is used when the paper type is set to plain paper.

The smaller black ink tank is a dye based ink.  This ink provides greater contrast when printing photographs.

The printer heats up the printhead to put ink on the paper.  It uses ink to keep the printhead cool.  If there is no ink in the ink tank, the printhead would overheat and become damaged.