Hide Print to PDF Button

I have a custom Print to PDF button setup inside the form .

The default one in the ribbon generates PDF misaligned .

Now i like to hide the default  Print to PDF button .

Tried using this code , didn't work . could anybody help me with this 

if(isNewMode)
{
.ms-cui-tabContainer ul li:nth-child(4){
visibility: hidden !important;
}
}

if(isDisplayMode)
{
.ms-cui-tabContainer ul li:nth-child(3){
visibility: hidden !important;
}
}

if( isEditMode)
{
.ms-cui-tabContainer ul li:nth-child(5){
visibility: hidden !important;
}
}