Laserjet 4, XP, envelope printed through manual tray, won't feed from tray afterwards

Here's the situation:

1. Print an envelope through MS Word 2003, after opening the front of
the printer and feeding the envelope manually.

2. Print a regular document after this, and the printer requests a
page be fed through the front (manual tray).

3. After this, pages are pulled from the paper tray as expected.

The goal:

Eliminate section 2 above. IOW, after the envelope is printed, I want
the pages to start feeding directly from the paper tray again.

TIA!