If you are using your bank's Mobile App to deposit Vchecks, you do not need to use special paper or MICR toner. Just print your checks on plain paper.
However, most mobile banking apps are looking for all 4 corners of a check. Even if you place the printed check (8.5" x 11" with the check on the top 1/3) on a darker surface to photograph with the mobile app, the app will only see the top two corners of the check and may not recognize it.
The simple fix for this is to cover the bottom 2/3 of the printed sheet with card stock, a file folder, colored paper - pretty much anything - thereby creating the appearance of just the top 1/3 of the page with all 4 corners.
We use two sheets of card stock of the same color, putting the check on one and covering the bottom 2/3 with the other. See the photo below:
Along with the 2 sheets of card stock we keep a page to use as the back of the check with our endorsement and account number. Since all our checks are deposited into the same account, we just use the same "back endorsement" page for every check.
FYI, if you don't have a stamp or similar for your endorsement, you can use the builtin feature of Vcheck for that.