I’ve been investigating electronic paper recently. It looks like a very interesting technology that will have lots of helpful applications. Imagine, for example, a piece of fabric sewn into the bag you carry to work every day with a constantly updated train schedule.

I was hoping it would be a good option for Kiplinger Letter subscribers. Our people love to read in print, and only a small percentage take advantage of the digital option — despite the fact that digital readers get the letter a few days earlier.

Maybe electronic paper can bridge that gap, I thought, since electronic paper is a little more like reading on paper. I can envision a situation where we simply deliver the latest edition straight to a piece of electronic paper sitting on the subcriber’s coffee table or desk. It would have some of the haptic benefits of print, but it could be updated digitally.

Alas, it’s too expensive for now.

In the meanwhile, it seems there should be better options for getting good, old-fashioned paper to people a lot faster. After all, Amazon can deliver things more complicated than a newsletter, and often they can deliver it on the same day.

Why can’t every post office — or maybe even every postal delivery truck — have a printer, and insert mail directly into the letter carrier’s bag? It should be possible to have same-day delivery of something as simple as a four-page newsletter.

No doubt there’d have to be some standardization, since these printers wouldn’t be able to offer many options. The publisher may have to limit himself to 8.5 x 11 white paper in #10 envelopes, for example.

(We print on cream-colored 11×17 paper, folded to make a 4-page letter and stuffed in a cream-colored envelope with our logo.)

Adopting standardized format seems like a small compromise to get same-day delivery.

So … why hasn’t this happened? Here are some ideas.

1. To offer it nationwide, they’d have to have this equipment — and somebody to man it — at every post office, and some post offices are little places out in the boondocks. They might not get much use out there, so it might not be cost-effective.

Okay, but why is that a problem? If you can get same-day delivery at most post offices — or even just some — and regular delivery in other areas, what’s wrong with that?

2. Most mail isn’t as time-sensitive as a subscription publication, so there wouldn’t be a lot of demand.

That, I think is the main problem with the concept. How many people need same-day delivery of a printed piece of paper? For most of us, if we need something immediately we just email it.

So … while this would be a great thing for some very niche publications, I don’t think it has broad appeal. Which is too bad.