Hi Janesville
I understand the first page prints fine diagonal lines and then it prints properly after that.
I have provided a document to troubleshoot the lines printing. Shows you how to check the print settings, run a cleaning mode and calibrate the printer.
If you require further assistance please provide the following so I can assist you better.
What type of paper are you using?
Did you change the printer preferences to match the paper?
What are the settings set to?
Are you using Genuine HP toners?
What were the results from the Configuration Page?