you are looking for a macro or task scheduler
This link might bring some insight to what I am going to say.
You are best off creating a macro to do what you are trying to do. You would still need to be inside of
Solidworks though. What I am thinking is if you are able to you could create a batch file to make pdf's
of your drawings and that could be run outside of Solidworks. Just create a print routine printing to pdf.
Now with all of that said, if you have PDM, there is a viewer in that or better yet setup a station that has
Edrawings and those that are using the dxf files could access your drawings in a read only state.
You can check out this batch processing tool: http://www.angelsix.com/cms/
Or more likely you just need a macro, and assing it to save both a .slddrw and .dxf. I suggest reposting this in the "API" section of the forums, as it often gets different people watching it. Your requirement is very simple, you may even want to just dive into it yourself if you are familiar with VBA or another programming language.
Thanks for all the input. I figured it was an API routine I was looking for. I am COMPLETELY unfamiliar with writing or implementing them. I will repost in the API section and hope someone else has done it, and says here you go.