That depends on what version of Access you have installed, and what PDF
"printer".  I'm using Access 2002, which has a Printer object and
Printers collection that can be used as shown in the code below.  (Note:
this code is expecting the find the CutePDF printer, but failing that
will attempt to print to any printer with "PDF" in its name.)

'----- start of code (watch out for line wraps) -----
Private Sub cmdPDF_Click()

   Dim prt As Printer
   Dim intPrt As Integer

   If IsNull(Me.txtFromDate) Then
       MsgBox "Please enter the From date first!"
       Me.txtFromDate.SetFocus
       Exit Sub
   End If

   With Application.Printers

      ' Look first for the CutePDF printer.
       For intPrt = 0 To (.Count - 1)
           If .Item(intPrt).DeviceName = "CutePDF Printer" Then
               Set prt = .Item(intPrt)
               Exit For
           End If
       Next intPrt

       ' Did we find the CutePDF printer?
       If prt Is Nothing Then
           ' No.  Search for any PDF printer.
           For intPrt = 0 To (.Count - 1)
               If InStr(.Item(intPrt).DeviceName, "PDF") > 0 Then
                   Set prt = .Item(intPrt)
                   Exit For
               End If
           Next intPrt
       End If

   End With

   ' Did we find a PDF printer?
   If prt Is Nothing Then
       MsgBox "Sorry, I can't find a PDF printer installed on your
system!", _
               vbExclamation, "No PDF Printer"
   Else
       Set Application.Printer = prt

       DoCmd.OpenReport conTimeSheetReport, acViewNormal

       Set Application.Printer = Nothing
       Set prt = Nothing

   End If

End Sub
'----- end of code -----