All Adobe programs printing dots/jagged edges instead of clean vectors and text

Hi! I'm wondering if anyone can help with what I imagine is a "settings" type issue.

I am trying to print really basic stuff. Like, basic fonts and vector images in black and white.

When I try to print from Illustrator and InDesign, the images and text appear as tiny printed black dots (or, with thicker type, just super jagged edges). Like, it prints like a crappy rendering of the fonts and images.

Zooming in on the computer screen, it's all crisp, even when something the size of a 12-pt period, zoomed in to the size of my head. So, I do know what a vector is and that it's not a poor resultion image that can't be blown up.

The same fonts print beautifully from Microsoft Word, etc.

I'm attaching an image of a photo of a couple sentences that I printed in black and white (sorry I have whack lighting; it's just black toner on white paper). The sentences on the computer screen look normal.

I'm using a super basic printer--a Brother black and white laser printer (MFC-L2750DW). 

Does anyone have ideas, or is there any additional information I need to research about my settings or printer? Extra extra gratitude to anyone who can answer like you're dealing with a total newbie.

Thank you all so much in advance!