Why did I waste my youth pulling the sides off printer paper?
September 25, 2007 6:28 PM   Subscribe

Why did dot-matrix printers invariably take tractor-feed paper? Was there a technical barrier to using single sheets? Why didn't typewriters require tractor-feed?
posted by smackfu to Technology (28 answers total) 3 users marked this as a favorite
So that they could do multiple pages without you having to manually feed each page, like you had to do with a typewriter.
posted by The World Famous at 6:37 PM on September 25, 2007

Single feed requires a way to grab one page at time from a stack of pages. This requires a certain precision in the mechanics, a control system to determine when the page has been fed to to correct position, when it has failed and pages have jammed, and mechanical access to clear the jam. More complex -> more expensive.

Continuous tractor feed only requires a wheel; and bonus, the page's position can be easily determined by the amount of the wheel's rotation.

(No offense, but you've never used a typewriter, have you? Feeding a page into a typewriter and aligning it correctly wasn't trivial. I feel old.)
posted by orthogonality at 6:46 PM on September 25, 2007 [5 favorites]

There are a number of factors here. One is that laser printers and copiers do sheet feeding, which requires a clay-lubricated paper (over time, anyway). Another is that tractor-feed is good for preprinted forms such as checks and paystubs (and remains used for those in large part).

I think the key here, though, is that dot-matrix technology is fundamentally a line printer method. The printhead moves back and forth across the paper, the paper advances, repeat until done. The laser printer, on the other hand, is a page printer. It relied on pointing the laser instead of moving the printhead. The ink adheres electostatically instead of being sprayed onto the paper. This allows for more precise adjustment and movement than tractor feeding.

And of course there were typewriters that were tractor-fed. Most of them were teletype(writers), though, so as to allow for unattended operation at the receiving end.
posted by dhartung at 6:49 PM on September 25, 2007 [1 favorite]

History, mostly. Consumer dot matrix printers descended from the big iron printers like the DEC LA-180 which were tractor fed.

Daisy wheel printers, btw, usually were sheet fed (single sheet) and tractor mechanisms for those were add-ons.
posted by jdfan at 6:52 PM on September 25, 2007 [1 favorite]

Convergent evolution?

Dot-matrix printers were an outgrowth of Telex machines more than typewriters, and Telex took continuous-roll paper. From there it's a logical path to tractor-feed, to a) allow for perforation into a more human-acceptable individual sheet format, and b) to overcome the problems friction feed had with multiple-copy paper (Telex machines were notorious for slipping once you went above ~ two-copy paper).

Add to that the fact they were expected to run unattended - nowhere had a printer on every desk; in the beginning they were a one-per-office thing - and the simplicity of a tractor-feed mechanism vs a single sheet feeder that can take a 500 sheet ream, and you can see why. And tractor-feed persisted long after it was technically necessary, due to the need for accurate registration on things like pre-printed stationary (invoices, cheques, etc).
posted by Pinback at 6:54 PM on September 25, 2007 [1 favorite]

One of the advantages of tractor feed is for business forms. You can use carbon paper/carbonless paper multi copies with tractor feed and you can precisely position your text within the preprinted forms. Both were real advantages with state of the art at the time printing speeds.
posted by Mitheral at 6:56 PM on September 25, 2007

Heck, cheap inkjet printers I've worked with still feed 2 or more pieces at the same time. Especially on longer jobs. I'd say it was for simplicity.

I miss pulling off the sides. I also miss turning in programming assignments as one sheet of paper 10 feet long. I also miss making banners in Print Shop and using all 10 pieces of clip art they had. Hmm, football, balloons or floppy disk?
posted by ALongDecember at 6:57 PM on September 25, 2007 [5 favorites]

There were dot-matrix printers that took paper by the sheet. In general, people didn't like them. The Apple ImageWriter II is one example; it could use either sheets or tractor paper, and the sheet-feeder was somewhat less reliable. Tractor paper was 'fire and forget,' you could hit print and not worry about feeding pages or (usually) clearing jams.

In a lab setting, you usually only had to load the paper once, at the beginning of a fresh box, and then you could ignore it until it ran out. (Unless people messed it up, of course.)

Tractor feeding is just a simpler system than sheet feeding, and it took a while for people to realize that they didn't like tearing the little perforations off of their documents, and longer still for sheet-feeders to become reliable and inexpensive.
posted by Kadin2048 at 7:04 PM on September 25, 2007 [1 favorite]

They probably did this because there were only a few companies making printers, so they could charge you exhorbitant prices for the special paper.
posted by ZenMasterThis at 7:25 PM on September 25, 2007

Probably a price/performance thing. Sheet feeds require more elaborate paper sensors, more complex paper paths, more complex print driver software, etc. Early on there weren't that many printers that weren't sold unless they could do forms, carbonless copies, or run unattended, so tractor feeds were more the norm as form followed function. (didja ever try to run a postcard through a sheet fed printer? about as easy as pushing a rope.)
posted by Gungho at 8:03 PM on September 25, 2007

I vote for ancient simplicity. My first computer job had 132 column teletype terminals. Once every couple of weeks you put a new box of tractor-feed fan-fold paper under the terminal, and you are set. No paper-jams, no feed problems, just a giant box of paper on the output side that's still connected page-to-page. No pages out of order, you have 1000 pages of output that can't get mixed up because each page is connected to the next.

As a person who took 'typing' in High School, and was a computer nerd back in the 80's, I could go on and on and on for hours about tractor-feed vs. single sheet... The difference between a "typewriter" and a "printer" of the time was a *big* deal... There was a big deal between a typed page and a printed page, and there used to be special 'you almost can't tell that it's a printer vs a typewriter' paper that *almost* looked like a plain single sheet of paper.

Back in the day, single sheet feed vs tractor-feed was a $5,000 difference... with appropriate software, my tractor-feed Epson would output documents equal to $10,000 laser printers of the day... Feeding individual pages of paper was hard!!, feeding tractor-feed pages was much, much less hard.
posted by zengargoyle at 8:28 PM on September 25, 2007

Way back in the dark ages of 1985, I had an Epson RX-80 F/T printer, which incidentally is still supported by Windows XP (and you can still get ribbons for it).

This printer was special, in that it was capable of using either the pin-fed papers (tractor load) or using a traditional typewriter-like roller and platen (friction load) -- that had to be loaded one page at a time, and rolled into alignment, just like on a typewriter. Of course, as the works got dusty and dirty, it would occasionally feed slightly crooked.

So, unless you were printing something on letterhead, or some other sort of special document that needed special paper, the friction loader was much more of a pain than a benefit. (and forget it if you were trying to print something that hadn't had appropriate page-breaks added)

The pin-fed paper was cheap, and it fed much straighter. Until automatic sheet loading technology got cheap enough for consumer printers (HP Deskjet comes to mind), the pin-fed stuff actually worked somewhat better than the available alternatives.

I do not miss those days one bit.
posted by toxic at 8:37 PM on September 25, 2007 [1 favorite]

I believe the development that enabled sheet feeders to use plain paper efficiently is this one. H-P developed an X-Y plotter that created micro-registration on the paper as a feature, and the sintered rollers (in the linked abstract, "frictionally adherent surface") enabled plain sheets to be towed through the print area multiple times with high accuracy. The radii of the feed rollers, the sintered material and the microstepping were all necessary developments for plain paper feeding.
posted by jet_silver at 9:08 PM on September 25, 2007

The filing date on jet_silver's patent above is 1995. I had a DeskJet 500 as early as 1993, and the Laserjet IIP was introduced in 1989 as the first laser aimed at the home market (cite[PDF]). Both used sheet feeders, though not ones that offered the kind of control needed for a plotter.

Businesses had been using sheet fed lasers, plain paper fax, and photocopiers for some time by then -- but they were still very expensive pieces of machinery that came with service contracts and technicians that visited regularly.
posted by toxic at 9:44 PM on September 25, 2007

I also miss making banners in Print Shop

Hardcore geeks used banner. I recall being amazed one day when the sysadmin hooked the line printer up to the PDP box and, instead of the printer's usual mundane duty of printing out ASCII pinups and rude limericks, it now printed a UNIX login. I logged in and read Usenet through print-out... definitely my noisiest online experience.
posted by meehawl at 10:06 PM on September 25, 2007 [1 favorite]

They probably did this because there were only a few companies making printers, so they could charge you exhorbitant prices for the special paper.

That is so not true. During the time when tracter feed was popular, there were countless makes and models of printers, and they all used the same standard size paper. Businesses went through this stuff by the boatload, as did home users. You could buy it at the office supply store by the box for pennies, it was dirt cheap, because it was standard. As someone said already, compared to the special coated paper that inkjets use, a dot matrix could practically print on anything from tissue paper to cardboard, so the paper was very cheap as it didn't need any coating. If anything, the tracter feed paper was a godsend to people that printed a lot of text because you could just stick a large box of it at the base of your printer, start the print job, and come back the next day and have 10 reams of printed material. It automatically folded and stacked itself on output.
posted by Rhomboid at 12:39 AM on September 26, 2007 [1 favorite]

I've always had a soft spot for dot-matrix printers. Before inkjet came along with its astonishingly expensive consumables, I had one of the pinnacles of personal dot-matrix printing (I think it was an IBM Proprinter 24) - it had a sheet feeder, tractor feed, 24 pin multistrike producing, err, pin-sharp text, and would knock out thousands of sheets on one cheap inkbelt.

Continuous feed is such an obviously superior way of printing source code, for subsequent sticking to wall and drawing on, that I'm shocked that coders don't jealously hoard the things.

(Although when printing it did sound like screaming electronic death.)
posted by Luddite at 2:23 AM on September 26, 2007

When computers had enough of a consumer base to support new styles of printers then dot matrix printers became a thing of the past. Compared to current ink jet printers, dot matrix printers were much more reliable and extremely cheap.
posted by JJ86 at 5:49 AM on September 26, 2007

1. History- Dot matrix printers were designed for business use, and only later adapted for home use. The 1st dot matrix printer I worked on was the IBM 3215 (which came out in 1970) which was used for printing endless amounts of console logs. This kind of application doesn't have any need for single sheets.

2. Ease of use- tractor feed is orders of magnitude simpler than page feed. All you need is a stepper motor and 1 EOF sensor. Jamming problems, alignment problems, humidity & temperature problems occur so much less often.

3. Speed- pinhole paper can go through a printer so much faster, mostly due to #2 reasons. The IBM 3800 came out over 30 years ago and still prints at 216 pages a minute (newer printers are much faster). The current fastest page printer IBM has prints 138 pages a minute.

(Pardon IBM reference point-of-view, but it'swhat I worked on)
posted by MtDewd at 5:55 AM on September 26, 2007 [1 favorite]

"I've always had a soft spot for dot-matrix printers. "
posted by Luddite at 4:23 AM on September 26 [+] [!]


I remember the days of micro-perf pin-feed paper you could use as regular letter paper. After my original Apple Stylewriter, I had an early inkjet printer from Kodak that was tiny—the size of a trade paperback—and could run on a brace of D batteries. In 1990 or thereabouts, it was the last hurrah for pin-fed consumer-oriented printers. As others have said, pin-feed was much more reliable and much faster than friction feed (this thing only had manual loading for friction-fed pages).
posted by adamrice at 7:03 AM on September 26, 2007

216 pages a minute
/Kicks LaserJet. Regrets it.

Are these things available for the common man?
posted by bonaldi at 7:50 AM on September 26, 2007

Tractor feed: cheap, simple, reliable, high capacity
Sheet feed: expensive, complex, not as reliable, low capacity

One major downside to sheet feed in ink jets (which is still problematic) is the inability to print to the lower inch and a half of the page. Tractor feed can hit the whole page (as can laser printers).
posted by plinth at 9:15 AM on September 26, 2007

One major downside to sheet feed in ink jets (which is still problematic) is the inability to print to the lower inch and a half of the page.

Eh? Full bleed coverage has been available in high end inkjets for years now and is trickling down to consumer models.
posted by nathan_teske at 9:28 AM on September 26, 2007

So you could make banners (see also) with PrintShop. Duh.
posted by aladfar at 11:51 AM on September 26, 2007

Dammit, a bunch of people beat me to the PrintShop nostalgia. I really should read through the all the comments before posting something I think is clever.
posted by aladfar at 11:52 AM on September 26, 2007

The IBM 3900 laser printer uses tractor-feed paper because it has extremely high throughput. The last company I worked for used one to print the complete court records for a large city every night.

For large tractor-fed runs, a shop can buy a "burster" for popping the pages apart and cutting off the perforated edges.
posted by Crosius at 1:09 PM on September 26, 2007 [1 favorite]

Are these things available for the common man?
Sure, if the common man has lots and lots of money. IBM would be happy to sell you 2 IP4000's. I don't recall the price (probably less than $1/4 million). That doesn't include maintenance and supplies, and you'd probably want roll feed to go with that, but they will kick out 1002 images per minute.
Also, the common man would need 3-phase power.
posted by MtDewd at 6:52 AM on September 28, 2007

God that'd be sweet though. You could print out all of Mefi to read on the train in the morning.
posted by bonaldi at 9:01 AM on September 28, 2007

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