Hi,
I'm an electronic engineer with more than 5 years of experience in system development related to raspberry pi. I have worked on these type of projects before, so I can develop an application that will run on raspberry pi so you can access printers connected to it.
So for my understanding is that, you have an mobile app, which is connected to Internet and it sends some commands to Internet server. Rpi will be also connected to server and get the correct commands accordingly and print the data received.
I'm confident on developing this project successfully. Also I have raspberry pi at my end to test things before sending to you.
I can send you a complete rpi Image, so you can directly burn that to your SD card and immidiately test it.
Looking forward to hearback from you.
Thank you
Anusha