process printing

[notregister]

I have been trying to print a document using process, how do i specific which
printer to use using the following, without opening out the printdialog box

let say i have a printername as a string, e.g printername = "Epson Stylus
4000C"
how do i point the print job directly to this printer

Imports System.Diagnostics
..
..
..
Dim psi As New ProcessStartInfo()
With psi
.Verb = "print"
.WindowStyle = ProcessWindowStyle.Hidden
.FileName = "C:\filename.pdf"
.UseShellExecute = True
End With
Process.Start(psi)