Use of IF function in google spread sheet for arrays

I am trying to understand to use properly the IF function in Google Sheets for an array of cells. My problem is the following:

I want to sum some data in a row, let's say from D12 to N14, but I want to check if any of the cells is empty with the function ISBLANK and to show a result if and only if at least one cell in the range is not empty.

Hence I used the formula =IF(ARRAYFORMULA(ISBLANK(C14:N14));; SUM(C14:N14)). Unfortunately, the result is not what I expected. For instance, if the second cell is not empty and the first cell is empty it does not perform the sum. It seems that the function ISBLANK checks only the first cell.

So the question is: How can I use in a more proper way the above functions?