My guess is the purple lines and other unwanted elements are on Illustrator layers that are turned off. These layers might still exist on the saved PDF, but ordinarily they won't print or appear on screen. They might print and appear in the print preview if the PDF is opened in a viewer that does not recognize layers, such as a browser. If this is the case, you have done nothing wrong, and your printer needs to print your PDF from Acrobat or Reader.
You can remove the turned-off layers when saving as a PDF by deselecting the option Create Acrobat Layers from Top-Level Layers in the save-as dialog, although this is normally not necessary.
Edit: A PDF saved with the option Create Acrobat Layers from Top-Level Layers in the save-as dialog will appear to have only one layer when inspected in Acrobat (or printed from a browser), however the turned-off layer will still appear when the PDF is opened in Illustrator. So if you really want to get rid of that unwanted layer, (possibly for security reasons) your best option is to delete it in Illustrator before saving as PDF, or deselect the option Preserve Illustrator Editing Capabilities.
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