Can I print from my ipad 4 to Brother MFC-7840W printer

See:

• Use AirPrint to print from your iPhone, iPad, or iPod touch - Apple Support
• Connect an AirPrint printer to a Wi-Fi network - Apple Support

Apple AirPrint is a driverless connection protocol - that requires a compatible Printer to be wirelessly connected to your WiFi network. A high proportion of modern printers intended for Home, SoHo and Business environments now support AirPrint. Check your printer model against this list:

About AirPrint - Apple Support

If your printer is not compatible with AirPrint, there are alternatives…

Some printer manufacturers have a suitable companion App that provides Print capabilities for mobile devices, often using a web-based print service. Others can print directly if the App supports other network printing protocols. By example, some HP Printers use the HP Smart App - available in the App Store:

https://apps.apple.com/gb/app/hp-smart/id469284907

You might also consider connecting a non-AirPrint printer to a PC or Mac computer - and install a “helper application” that allows the computer to emulate AirPrint capabilities; one such option is Readdle Printer Pro, for which suitable software for PC is available. A link to the PC software is included from this page:

https://readdle.com/printerpro

A further alternative is to consider installing a dedicated Print Server Appliance on your network - and connect your printer to this. One example is the Lantronix xPrintServer.

The remaining solution is to simply replace your printer with one that is AirPrint capable.

Hi,

The Brother MFC-7840W does not appear to be listed as a supported AirPrint model.

About AirPrint - Apple Support

The printer model as such seems to be supported by Brother iPrint&Scan, an app for iOS/iPadOS.

https://support.brother.com/g/b/downloadlist.aspx?c=us_ot&lang=en&prod=mfc7840w_all&os=112

However, the Brother iPrint&Scan specifications for the latest version indicate that iPadOS 14.0 or later is needed (which would not work with an iPad 4).

https://apps.apple.com/app/brother-iprint-scan/id382775642

So, unless an earlier version (compatible with your iPad) exists, you will have to look for another solution/workaround.

If you have access to a Mac OS X 10.7 Lion or newer Mac computer (with working printer drivers for the MFC-7840W), you may want to check whether a Mac application like Printopia (https://www.decisivetactics.com/products/printopia/) possibly could be of interest to you. The idea is to use the Mac as a print server, thus allowing iPhones/iPads to connect via the same network as the computer.