Recently there have been several machines capable of applying ink, wax, or other media directly onto a screen's layer of emulsion to replace the positive. Basically everything we need from the positive without the film. More on this later.
Without waxing poetic about the past or pontificating too much lets look at the issue of positives, RIP software, and exposure.
Back many years ago when many of us were foolish enough to think that we could get away with "laser printer" positives, we tried to replace our far superior silver/chemical based film positives. Our camera shots, even the PMT shots had both darker "blacks" (a higher D-Max) and a clearer base film (D-Min) than vellum or the frosted film. We thought that we were saving time and money by shooting toner based positives quickly from a laser printer, we sprayed them with a repackaged artist-fixitive (something that always worked better than hair spray - it was the evaporative solvents that did the "melting" of the toner) and passing the quickly printed vellum to the screen room.
Of course this only cost the "screen room" time and effort - far more than we were saving in the "art room" we were soon forced to shoot paper positives with the old manual cameras to make reasonable positives. This did not last long, and as soon as we were able to justify to the ownership we needed an image-setter, life was good. We had more time for more artists to print more product. Production with excellent positives shot to the roof, and that was when a Harliquin RIP and a VLR image setter with chemical developer was a 48K investment.
In the industry there has always been the old argument over what was more important D-Min or D-Max. the REAL issue is CONTRAST it is not just the clear of the film or just the dark black but BOTH. We want the best of both, simply better is better, high quality always trumps mediocrity.
Discounting the need for a good D-max is showing a basic misunderstanding of how electromagnetic energy or "Light" works and how emulsion is exposed. Light waves never "slow down" - light is light and it either is blocked, bent, (refraction), or filtered. Light continues on - always the same speed - the speed of light. Reaction times change in emulsions based on the volume of light energy.
The lower the D-Max the less light is blocked (more accurately filtered) and the more electromagnetic energy passes through the dark areas. The dark areas of the positive control how much light is filtered, the lower the density/opacity the more light will pass through into the emulsion layer. Regardless of how powerful or fast the exposure the light always is the same speed and any light that passes into the dark areas of the positive and is not filtered continues on to the emulsion and starts the exposure reactions in the emulsion.
Here is an example of a poor black on a positive, even with a ridiculously thin coating of emulsion to compensate by shortening the exposure - it clearly did not work. A correct and full exposure has this and other negative results with a poor positive.

It is always in the facts, the microscope tells all, poor positive, poor results or you are forced to underexpose.
What does this have to do with a RIP?
Inkjet printers without a RIP in front will only deposit a particular pre-determined amount of ink on each dot from the piezo head, this is measured in picoliters (One millionth of a microlitre; 10-12 liters) a very small amount of ink, and that is always set at about 3 to 4 with the free software for the printer.
Epson printers have this setting infinitely variable via the information sent by the printer driver, in other words Epson left their inkjet printers open to performance modification by software.
To modify the inkjet ink deposit you have to have software that will change the ink deposit. The free driver supplied by the manufacturer is designed for ink deposit to give pleasing or accurate color and will be limited in ink deposit volume to about 4 picoliters per dot including the black inks.
With a RIP the printer is "told" to "squirt" enough ink to fulfill the demands of the user, and the RIP makes this much easier to adjust often with settings from 6 picoliters to 27 picoliters or more per machine dot printed - that is each machine printed dot not the formed "dots" you would adjust as "LPI/frequentcy" in your vector or raster program. Contrary to assumptions a RIP not only converts the image but tells the printer EXACTLY WHERE (so it holds registration) to put a dot and HOW MUCH INK to deposit.
With a thin, poor black as the dark areas (D-Max) the black becomes like the darker areas of an exposure calculator - not dark enough to block or filter all of the light energy and some of the emulsion is exposed behind the black, the more full and complete the exposure the more the open areas under the black are exposed leaving remnants after wash development and forcing the user to "blast" the open areas excessively leaving ragged edges.
With the poor covering of ink from the standard driver you do not create a black that will block sufficient light to keep the emulsion from forming a skin of slightly exposed emulsion over the face side UNDER THE BLACK. To then open the stencil we would have to put enough pressure on the open areas in wash development to "break" the edges of this "skin" off and that will result in an edge that is rough and will present a less than desirable printing "gasket edge" against the product.
Professionals use professional tools, using a RIP has other advantages, the biggest one in art production is using the graphic tools we have correctly. No real graphics professional wants to go back to breaking jobs up and fidgeting with photoshop to get dots or separations, directions for this procedure you can find on the internet for free, but the results are a poor D-Max and the resulting problems.
Postscript a beautiful thing, no serious artist is going to go back to the days before the introduction of Adobe separator (a program that is now imbedded inside of Illustrator and has been for over a decade).
Not using good quality film, quality inks, and a good adjustable RIP, a printer cannot get the real and required contrast from D-Min to D-Max to get positives that will allow professional results with full and complete exposure. The combination of special film for positives, ink designed for positives, and an adjustable RIP are the tripod of good positives with an inexpensive inkjet.