ScanDPI

ScanDPI is an Xposed module which allows you to scan documents with an arbitrary resolution using HPs All-in-One Printer Remote application, which by default is limited to 300 DPI. With this app you can release the true power of your scanner.

Note that this application requires Xposed framework (which in turn requires root access) to be installed. More information about Xposed can be found here: http://repo.xposed.info/module/de.robv.android.xposed.installer

If you are interested in the source code of this application. Please check out the github repository:
http://github.com/deckaddict/ScanDPI.git