I run all kinds of envelopes on my 3302. There are several tricks to it.
The main thing is to take into account that unlike most presses with an feed roller infeed, this design shoots the stock into the bottom of a transfer drum moving downwards, instead of the top of an impression cylinder moving upwards. This means the stock is going into a set of grippers that open and close from the bottom.
The consequence of this is that if the envelope flap hangs down as it would if the envelope is fed with the short edge as the gripper, that flap will conflict with those grippers, causing frequent misregister and jams with potential damage to the flying head stops of the transfer drum. Imagine that you could see through the side frames and watch in slow motion as the feed rollers close on the envelope distorting the flap as it shoots the envelope into the stops and forms the buckle that will be maintained until the drum grippers are closed. The result will vary with the different shapes of that flap from different envelope converters.
This conflict can be avoided entirely by running the envelopes with the long edge as the gripper edge. This requires buying lots of extra wheels for the feed board, and placing them close enough so that the envelope is never free as it moves down the belts on the feed board. I use 7 pairs of wheels for a #10 envelope. Near the rubber tires at the beginning of the belts two pairs point toward the feeder, the rest point toward the press. But first set of the forward pointing ones mount on the bars *between* the rear pointing ones but on the other side of the mounting bar, so that the hanging arms of the 2nd and 3rd pair can cross past each other in opposite directions. This may sound confusing, but it's the only way to get the wheels close together to always have wheels on the short sheet that is an envelope running with the long edge as the gripper. The last pair have springs so that they don't rely only on gravity.
Now in the area of the side guide you will need an extension to reach the short sheet at the stops. Ryobi makes one for the push guide with a stiff spring feather and one solid one for the opposite side. You need to get these from them because they have small wing screws installed for attaching to the existing guides on the press. I replaced the spring feather with a rigid metal strip with a cut out to clear the tape roller at the bottom of the ramp and for the rare two pass work I do use a spring on the opposite side.
Now for the envelope feeder. I currently use one by Astro (AMC-2000) which is timed electronically to the press. Press Specialties also makes one. And here again you need extra wheels over the feeder tapes to hold the envelope at all times.
Keep a separate set of blankets just for envelopes.
With this rig up I routinely do one pass two color envelopes at 6,000/hour. I have done occasional two pass close register work at 3-4,000/hr. with very careful make ready and LOTS of spoilage, but I do NOT recommend this.
Oh yeah, I do use a delivery conveyor. The delivery challenges are the limit to the speed.
I hope this helps.
Al
