$printerlist = @(
"HP1",
"HP2"
)

$a = ""

foreach ($printer in $printerlist) {
    $a = Get-WMIObject Win32_Printer -Filter "Name = $printer "
    switch($printer) {
        "HP1" {$a.DriverName = "DriverHP1"}
        "HP2" {$a.DriverName = "DriverHP2"}
    } 
                                                                           
    $a.Put() 
}