I realize this is 7 years ago but I am putting my answer out here for the benefit of others. my guess is that it is a print setting on your computer. The same thing happens on my mac. After nearly a year I figured out from the print window (which may be custom for adobe products) to click "advanced" from there is a checkbox to "Print as Image 72 dpi" I unchecked that box and things are good now. Same is likely on the PC.
"https://helpx.adobe.com/acrobat/using/advanced-pdf-print-settings.html"
"
In the Print dialog box, click Advanced.
If a custom printer settings file exists with the settings you want, choose it from the Settings menu. Otherwise, choose Acrobat Default.
Note:
To learn more about an option, select it. A description of it appears at the bottom of the dialog box.
If normal printing doesn’t produce the desired results, select ***Print As Image*** and choose a resolution from the drop-down list."
