If the data is on the same line number, and in the same character position every time, this should get you started
Dim lines as String() = System.IO.File.ReadAllLines("log.txt")
For Each line as String in lines
'Process line
' If line is 12, get printer name
Console.WriteLine(line.Substring(34,lengthOfPrinterName))
Next
Alternatly, you could index directly to the 12th line, since lines is an array of type String.
lines(12).Substring(34,lengthOfPrinterName)