‘...completely obvious...’ Is that right ! Well get THIS ... An iPhone is WIRELESS, obviously. The Wireless Brother Printer is WIRELESS, obviously. Ergo...Many users might think (logically, I might add) that those 2 factors will allow for a WIRELESS CONNECTION using BlueTooth. Ergo...You just need to “Pair” the two like so MANY other wireless products can be used. Especially when it ABSOLUTELY can be done just like that with a WIRELESS Canon Printer WITHOUT needing WiFi. I printed that exact way for 2 years !! And also get THIS: I have the SAME ISSUE as the User you so rudely replied to, with my newly purchased Brother HL-L2395DW Wireless All-in-One Printer/Fax/etc. I worked @ finding an answer to it. Until I was somehow (& WITHOUT WiFi) able to get my iPhone’s (wireless obviously) BlueTooth connection to finally show up on my Brother Printer’s (wireless obviously) screen under “selection” of Wireless “connections” to choose from. And guess what ? I was able to wirelessly print a document from my iPhone 7+ WITHOUT a wireless network !! So... Your wrong that it “obviously” MUST have a “wireless network”. Obviously.
And now I’d like to address the original question:After I printed (as detailed above⬆️) the document I needed, I shut down my iPhone. Then,the next day, after I fired-up my iPhone, I wasn’t able to get my iPhone’s BlueTooth connection to AGAIN show up on my Brother Printer’s screen selection. I’ll will again(but not sure when) try to “repeat” my earlier steps to get my iPhone to show up on my Brother Printer. When I do, I’ll post my steps in this MacRumors Forum. I believe Brother is selling a Wireless Printer that doesn’t equal the Wireless functions of Canon Wireless Printers. I now wish that I’d purchased another Usr-Friendly Wireless Canon Printer, rather then a Usr-UNfriendly Brother’s Printer.