Can I automate and send Invoice PDF when payment is received

Can I automate and send Invoice PDF when payment is received

My Process is as follows:  
  1. We create EST.
  2. We convert to SO
  3. We then convert to INV when customer approves purchase.
    1. We send INV for payment
We are needing an automation that emails the INVOICE PDF to our HP Printer automatically.

My initial thought was that we could do it in the "automation" section - that that just seems to email notifications and NOT the entire PDF invoice.   We use the invoice in our order fulfillment process.

How can I accomplish this?  Is there a way?  Are there better ideas?
thanks!
Greg