10 ms·

Why Paper Jams Persist

242 points by ohjeez 9y ago

nwah1 9y ago
This is why I love the New Yorker. You don't see enough of this kind of long form journalism, shedding light on seemingly mundane issues that you'd never imagined could be so interesting. The historical perspective, in particular, was great. But what took this to another level was detailing just how big the challenges are, and how enthusiastic the engineers are in trying to solve them. Even giving a sense of vicarious excitement from the descriptions of their attempts at problem-solving.
- fredley 9y ago
  I've been reading Delayed Gratification for a year now. It's all this sort of stuff. If you like long form journalism I highly recommend it. https://www.slow-journalism.com/ https://www.slow-journalism.com/
  - Overtonwindow 9y ago
    Thank You!
  - lighttower 9y ago
    Thank you for this. I've been deliberate in not reading news for a couple of years now. I subscribed to the Atlantic Monthly print edition which is slow enough to get some digestion rather than velocity. The most important outcome in looking for is reduction in anxiety and avoidance of getting sucked into pointless debates... It's very effective to say you never heard of Jordan Peterson (I heard of him last night) and you're thus physically unable to participate in the ensuing gender politics melee. What I notice about myself lately is that I go to Google news whenever I'm anxious or avoiding something. It's would be instructive to plot my browsing history to news sites with actual anxiety over time
    - fredley 9y ago
      Wanting to cut down on news consumption was one of my original motivations for subscribing. While I haven't cured myself entirely, I'm able to keep it a lot more under control. Reading about Trump and Brexit every single day was having a very negative effect on my mood and outlook. I remain aware of the stuff that matters, without having to deal with the blow by blow every single day.
- djsumdog 9y ago
  I dunno. I think this is one reason I stopped reading the Atlantic/Harpers/New Yorker. I mean, it is better than sensational TV where they take 45 minutes to get to the punch line where they could have explained it in 5 min. It's not even 40 min of interesting facts or history; just mostly commentary and talk to draw things out. I do realize this article is different; there is a lot of historical fact and context which helps create a narrative. It has its advantages. Maybe I'm just getting old. I read a lot of novels and I'd rather spend the time on that type of narrative in a novel or even a non-fiction book than a news article. People may criticize the YouTube generation, but it has helped in content creators who get a lot of information over in a very concise way (Kurzgesagt In a Nutshell, Smarter Every Day and Wendover Productions come to mind). I think the opening of the historic paper jam made me want to fall asleep. The later office space references and Xerox design became more relevant. Even then, I feel like I don't read these articles the way I did back when I bought a physical Harpers from the book store. It's a lot of content, and in the scrollable world we just end up skimming more these days.
  - emodendroket 9y ago
    It's the medium. If you read the same thing on paper or on a Kindle the temptation to skim would be much less.
  - hycaria 9y ago
    >People may criticize the YouTube generation, but it has helped in content creators who get a lot of information over in a very concise way (Kurzgesagt In a Nutshell, Smarter Every Day and Wendover Productions come to mind). Reading the same info (in a non-narrated way) would be much faster. Also it's often concise over exactitude or neutrality. I can't sit through these videos, boring or caricatural. At least the New Yorker is sold as an enjoyable distraction, and I find great pleasure in reading nice writing.
  - Angostura 9y ago
    > or even a non-fiction book than a news article. This isn't a news article. Perhaps it would help if you thought of it as a freely available, very short non-ficton book.
- jrgaston 9y ago
  Agreed. I read most New Yorker issues cover to cover. Their writers cover a wonderfully-broad range of topics in useful depth. It's the only print publication that I still subscribe to.
  - emodendroket 9y ago
    I like the London Review of Books.
24gttghh 9y ago
I still hate printers, and their jams, but I must reluctantly appreciate the engineering behind them after reading this. This seems quite clever: 'Corrugating is when we put an intentional wave in the sheet, like in a piece of corrugated cardboard,” Vicki Warner explained. “It adds stiffness.” The plan was to corrugate the sheet lengthwise by running it over a line of rollers turning at variable speeds before “flying it” into the stacker. If a physical fix was necessary, a part might be 3-D-printed and installed, on-site, by one of the engineers.'
- asciimo 9y ago
  The challenge helps explain why the user experience for desktop printers hasn't changed much in 25 years.
- jeremy7600 9y ago
  I have been a part of this process at Xerox.. it works quite well.. I've been involved in a number of different aspects of it as well. I've been the source of some of these fixes, I've been the source of some of the issues, and I've been involved in the investigations to solve them. Xerox has a few different labs for testing different things. The "stub point" is a common thing, and can be very, very difficult to pinpoint. They had one specific finisher that kept jamming when you printed to the top tray. It didn't jam 100%, it was pretty intermittent. Well, this finisher had been in another lab for a few weeks or so and they couldn't find the source of the jams or a pattern to them. I had the finisher installed on one of my machines in the 3 days I'd solved it. There was a small stub of plastic on a flag for a sensor. The flag sits in the paper path, and when its moved, the sensor changes state. So this flag has an pretty smooth surface so as to not catch the paper, but somehow this one got a little nick in it. Enough to cause a jam when a sheet ran right into the nick. I filed it down and the machine never jammed again. We had another issue with a printer at a customer site and the issue dealt with static electricty. a 30kv ESD gun and the inside of a printer.. we still never solved the issue.
zwieback 9y ago
It's even worse in our low-end inkjets, which are made of plastic parts and toy motors and are still expected to duplex-print on the cheapest crap paper imaginable. Our FW devs spend a lot of time perfecting the PID loops and mech sequences to make this happen. But do we get any thanks for that? Noooo... Love that New Yorker article, though. I grew up reading this magazine in the 80s but drifted away. These great articles straddling tech and culture became too few and far between.
jws 9y ago
Exciting fact: Similar jams happen in hot steel rolling mills too. The YouTube videos are just prettier: https://www.youtube.com/watch?v=DVZ1DY0r4y4 https://www.youtube.com/watch?v=DVZ1DY0r4y4 In general the rolling mills call it a "cobble" when a whole or partial bit of steel escapes the rolling mill. Lots of exciting videos.
- djsumdog 9y ago
  That's pretty insane. Wow, look at those coils of hot metal. It's interested how much of it is still hot after they clear the jam and run it through. I remember years ago hearing about how the US mint misprinted over a million and had to destroy it (and on the Colbert Report, he joked about how them destroy it by burning it in front of poor people). We were talking about it at a party and someone asked, "surely they noticed? Why didn't they shut it down?" An engineer in our group said, "Have you ever been in a factory? It's so fast!" He worked in a toothpaste tube factory where you'd see hundreds of tubes come out every minute. If something went wrong, you'd have to wait for the whole pipeline to clear. Fab shops in China are even more insane. I wonder if the mill would just sell those sheets at a reduced price as low grade/for non-visible construction or if they re-melt them down and run them again.
  - rzzzt 9y ago
    Or as a piece of artwork.
  - bartread 9y ago
    On the speed front, I concur. Back in 1998, when I was on summer break from university, I worked in a wines and spirits bottling plant. One day the labelling machine started applying wonkey labels to the wine bottles and a couple of hundred had gone through before the guy running the machine had noticed. They weren't wildly misaligned, but far enough from true that we had to wash them off and run them through the line again. Took a couple of us most of an afternoon to sort it out.
    - giarc 9y ago
DubiousPusher 9y ago
I enjoyed the article. Just want to point out briefly that the explanation given in the article of how airplane wings create lift is incorrect. http://www.explainthatstuff.com/howplaneswork.html http://www.explainthatstuff.com/howplaneswork.html
- giarc 9y ago
  I think they just messed up what side is flat, right?
  - DubiousPusher 9y ago
    That's part of it but it's also incorrect to say "the air above moves faster than the air below, and the wing rises." The air speed is not necessarily different. Lift is generated because air is deflected from moving over the top of the wing and thus reduces the air pressure. You can create flat winged aircraft with careful orientation of the wings. Air flow is not like say a spinning disk, where the solid state of the matter forces the outer edge of the disk to move faster in order to maintain relative position.
  - aidenn0 9y ago
    No, symmetric airfoils generate lift just fine, and if you were going to spend half your time upside-down, you'd use one. Making it asymmetrical merely makes it more efficient to generate lift in one particular direction (similar to how glasses lenses are asymmetrical to reduce distortion). Furthermore, pretty much no airfoils have flat sides, in nature or in engineering[1] The wing, when placed in airflow, disturbs the air in such a way that the pressure on top of the wing is lower than the pressure below the wing, generating net lift. This isn't a very satisfying description of lift, since it just begs the question of "how/why does it disturb the airflow in such a manner" and the short answer is "we put different shapes in a wind tunnel and measured" with the longer answer being "you don't know enough math to get a good intuition of that" [edit] After reading the article, the article did get lift right for the case of the paper though. Jets of air behave exactly as they say, and you can feel something similar by touching the back of a spoon to the stream of water from a sink; it will get pulled towards the stream of water (or just put a piece of paper on a table and blow over it). A few planes use blown flaps[2] to help get a similar effect (the introduction of a jet of air, which "hugs" the wing helps direct the airflow of the larger mass in the direction you want). 1: https://en.wikipedia.org/wiki/Airfoil#/media/File:Examples_of_Airfoils.svg https://en.wikipedia.org/wiki/Airfoil#/media/File:Examples_o... 2: https://en.wikipedia.org/wiki/Blown_flap https://en.wikipedia.org/wiki/Blown_flap
leandrod 9y ago
Page wide, Precision core.
- deleted 9y ago
  [deleted]
minikites 9y ago
The "Secret Life Of Machines" episode about the photocopier is also illuminating: https://www.youtube.com/watch?v=S2NIAD5qn7E https://www.youtube.com/watch?v=S2NIAD5qn7E
- djsumdog 9y ago
  Wow, that's really interesting. I didn't realize that's where the term "blueprint" came from.
- joosters 9y ago
  Tim Hunkin's TV programs are excellent!
preinheimer 9y ago
I wonder if we could go jam-free with Continuous Stationary ( https://en.wikipedia.org/wiki/Continuous_stationery https://en.wikipedia.org/wiki/Continuous_stationery ). That paper with the holes on both sides from the 80s, and some legacy systems today. It seems really helpful, but I'm not sure which problems discussed it would actually solve.
- PotatoMatch 9y ago
  Had a dot matrix printer that used continuous paper. Notorious for jamming. Usually something getting stuck on the little holes, or the perforated sides tearing mid-print.
  - strictnein 9y ago
    One of my first "tech" jobs was refurbing dot matrix printers after we had them in the field for a while. The amount of little bits of that perforated paper that would get stuck in every moving part in one of those was kind of staggering. People were also really rough on those things. Yanking at the paper to tear it as the printer was just finishing it up.
  - Moru 9y ago
    I had several dot matrix printers and can't remember any jams. And I did manage to accidentally dump the whole database to the one at work, the stack was at least 5 cm thick by the time we managed to stop it. It had it's own room though because of the sound so not your normal home printer...
  - astrodust 9y ago
    The worst was when it lost traction, shredded the holes, usually in a tangle of paper. There'd also be cases where it kept pulling on the holes but those separated and got gummed up really badly. When you try and tug the pages out they're all perforated so you get, at best, a single page. It can be a lot of work to clear a jam. Most people think of dot matrix printers as slow, lumbering things that would take measurable time to print a single line. The industrial ones, enterprise grade, made by companies like IBM were dizzyingly fast, pages per minute, so if a jam happened it was usually severe. Most had multiple print heads to speed up printing. These also used much wider paper than normal for things like accounting reports. When they jammed, they jammed.
interfixus 9y ago
Many, many years ago I had a student job with a small company doing industrial document finish, enveloping, and large-scale mailings. Apart from a still eaily induced paper eczema, the one thing I took with me was a rather comprehensive facility with the black magic of paper handling. Not an ounce of explicit science in it, but an awful lot of feel: When and how much to air and flex; where a grounded length of copper wire could work wonders; how much or how little moistening to apply, and where; how too touch the stream of paper and somehow know by the feel of the tip of your finger whether something would probably jam within a minute, and which tiny speed-adjustment up or down would probably forestall the disaster; when to to loosen or tighten this or that set of rollers because nightshift and the air getting cooler et cetera et cetera. To this day I never just bang a fresh stack of paper in the printer tray. The full gymnastics of airing, flexing, feeling, airing and flexing again. I'm often laughed at. But my papers never jam!
- giarc 9y ago
  I've seen people do this before, I always just assumed it was to make sure the pages weren't stuck together, and therefore reduce the chance of 2 sheets being pulled together.
  - interfixus 9y ago
    Well, it is, sort of. But in a fast moving production line, it could make a huge difference in jam propensity whether the sheets were fed by somehow with a nice touch or not.
- Taniwha 9y ago
  In college I worked in an old style (precomputer) printing shop - learning how to work with paper like that is something that never seems to leave you (I always do it when I load a laser printer too)
xefer 9y ago
I'd like to see another article on why in 2018 every meeting seemingly has to start with 5 minutes of fiddling with the screen projector.
- sushisource 9y ago
  Preach. Seems like someone could make buckets of money undercutting Cisco with a better product
  - cat199 9y ago
    in my experience, 4 out of those 5 minutes is a result of apple changing the requisite number and configuration of display adapter dongles every 2 days, with the other 1 minute resulting from from wifi network access policies being innane in most building common areas
- shard 9y ago
  Is that still a thing? For small meeting rooms (less than 10 people) our offices have large screen TVs (60 inch maybe?), and for larger meeting rooms it looks like there are NEC projectors (I just checked 1). I don't recall a project issue within the last 6 years.
  - asterius 9y ago
    Projector fiddling has been replaced with VTC fiddling. I hate Polycom/Skype with a far greater passion than any printer.
reaperducer 9y ago
Coincidentally, just last night I was telling my wife how impressed I am with my work's copier/printer machine. It's about the size of a 1980's copy machine, but my department easily prints a minimum of 5,000 color pages with it each day. Some days it's double or triple that. Sometimes with staples. We go through five massive toner carts each week. They're about the size of a fire extinguisher. In six months, I've seen exactly ONE paper jam. I told her I thought maybe they'd figured out this whole printing thing finally. But I guess TFA says I'm wrong.
- mathiasben 9y ago
  What's the make and model?
  - reaperducer 9y ago
    Don't know the model, but it's a Kyocera. Before this job, I'd only been exposed to that brand as one of the cheap printers for the Commodore 64. I guess it's come a long way!
smacktoward 9y ago
We take sheets of dried wood pulp, stack them so loosely you can always see a few that aren't 100% aligned with the rest, then feed them through a series of unlubricated rollers inside a machine that's usually indifferently maintained and clogged with dust, all while deliberately exposing them to heat and static electricity and spraying their surface with goopy ink or powdery toner. The surprise isn't that they jam occasionally, it's that we ever get anything printed at all!
thisrod 9y ago
I'm surprised that Xerox pays engineers to do all this, when so many companies would pay their lawyers to make it someone else's problem when an odd type of paper stock jammed in tropical weather. Making custom parts and flying out to fit them in production machines? I thought technicians only got to do that during wars. I suppose you might do it when the machine is the one that prints the price labels for Walmart, though.
- ocdtrekkie 9y ago
  I worked a couple years ago somewhere with iGen printers. Xerox guys were there all the time, absolutely top class service all the way when you're at this level of printing.
- Avshalom 9y ago
  I don't know about Walmart but here at Target we just use some random small business Epsons for the signing and Zebras (previously Monarchs) for the price strips and stickers
  - ComputerGuru 9y ago
    Zebras are indestructible. It’s what Amazon uses in their warehouses for everything. I was looking for a label printer and my options were a new dymo label printer from 2015 or a zebra released 15 years prior. The zebra still won.
    - skrebbel 9y ago
      They're also a lot of fun to code against, if you're like me and have a thing for ancient serial cable text protocols designed by electrical engineers.
      - ComputerGuru 9y ago
        I haven’t coded against the Zebras but I have against their counterparts from Epson with ESC/POC and fully concur. It’s like a throwback to the 80s or early 90s.
alricb 9y ago
> (Before railroads transformed the transportation of lumber, logjams had to be addressed by “jam breakers”—experts who spotted and removed the “key logs” jamming up the river.) River transportation of lumber kept going long after railroads came along. Jam would be broken using dynamite sticks. Here's a movie on the driving of logs on a river in the 1950s: https://www.nfb.ca/film/drave/ https://www.nfb.ca/film/drave/ Driving only stopped in the 1980s on that river.
- djrogers 9y ago
  Rivers are still in use for moving log booms today - you can see them on the Fraser river and other places in and around Vancouver BC - although they tend to be more orderly, with strict regulations around the logs being properly boomed and contained..
- severine 9y ago
  Thanks. You reminded me of "El río que nos lleva" (The river that carries us"), a beautiful spanish movie from 1989: http://www.imdb.com/title/tt0098239/?ref_=fn_al_tt_1 http://www.imdb.com/title/tt0098239/?ref_=fn_al_tt_1
GrumpyNl 9y ago
Inst this easy to solve by not feeding sheets, but from a role and cut after printing? Cheaper production and transportation.
Ftuuky 9y ago
I work for a major ICT provider that sells about everything enterprise related, from servers to storage systems, laptops, scanners, etc. In terms of customer support the printers are the absolute worst: usually it's always a critically important since they're used to print the labels for factory outgoing and if they stop for one hour it's millions of euros lost. This means the ticket will be Priority 1 and everything needs to be solved within minutes or else people will freak out since there's a whole factory plant jammed with cars, tires, whatever, that can't leave the factory without the printed stamp.
deleted 9y ago
[deleted]

242 points by ohjeez 9y ago

This is why I love the New Yorker. You don't see enough of this kind of long form journalism, shedding light on seemingly mundane issues that you'd never imagined could be so interesting. The historical perspective, in particular, was great. But what took this to another level was detailing just how big the challenges are, and how enthusiastic the engineers are in trying to solve them. Even giving a sense of vicarious excitement from the descriptions of their attempts at problem-solving.

fredley 9y ago
I've been reading Delayed Gratification for a year now. It's all this sort of stuff. If you like long form journalism I highly recommend it. https://www.slow-journalism.com/ https://www.slow-journalism.com/
- Overtonwindow 9y ago
  Thank You!
- lighttower 9y ago
  Thank you for this. I've been deliberate in not reading news for a couple of years now. I subscribed to the Atlantic Monthly print edition which is slow enough to get some digestion rather than velocity. The most important outcome in looking for is reduction in anxiety and avoidance of getting sucked into pointless debates... It's very effective to say you never heard of Jordan Peterson (I heard of him last night) and you're thus physically unable to participate in the ensuing gender politics melee. What I notice about myself lately is that I go to Google news whenever I'm anxious or avoiding something. It's would be instructive to plot my browsing history to news sites with actual anxiety over time
  - fredley 9y ago
    Wanting to cut down on news consumption was one of my original motivations for subscribing. While I haven't cured myself entirely, I'm able to keep it a lot more under control. Reading about Trump and Brexit every single day was having a very negative effect on my mood and outlook. I remain aware of the stuff that matters, without having to deal with the blow by blow every single day.
djsumdog 9y ago
I dunno. I think this is one reason I stopped reading the Atlantic/Harpers/New Yorker. I mean, it is better than sensational TV where they take 45 minutes to get to the punch line where they could have explained it in 5 min. It's not even 40 min of interesting facts or history; just mostly commentary and talk to draw things out. I do realize this article is different; there is a lot of historical fact and context which helps create a narrative. It has its advantages. Maybe I'm just getting old. I read a lot of novels and I'd rather spend the time on that type of narrative in a novel or even a non-fiction book than a news article. People may criticize the YouTube generation, but it has helped in content creators who get a lot of information over in a very concise way (Kurzgesagt In a Nutshell, Smarter Every Day and Wendover Productions come to mind). I think the opening of the historic paper jam made me want to fall asleep. The later office space references and Xerox design became more relevant. Even then, I feel like I don't read these articles the way I did back when I bought a physical Harpers from the book store. It's a lot of content, and in the scrollable world we just end up skimming more these days.
- emodendroket 9y ago
  It's the medium. If you read the same thing on paper or on a Kindle the temptation to skim would be much less.
- hycaria 9y ago
  >People may criticize the YouTube generation, but it has helped in content creators who get a lot of information over in a very concise way (Kurzgesagt In a Nutshell, Smarter Every Day and Wendover Productions come to mind). Reading the same info (in a non-narrated way) would be much faster. Also it's often concise over exactitude or neutrality. I can't sit through these videos, boring or caricatural. At least the New Yorker is sold as an enjoyable distraction, and I find great pleasure in reading nice writing.
- Angostura 9y ago
  > or even a non-fiction book than a news article. This isn't a news article. Perhaps it would help if you thought of it as a freely available, very short non-ficton book.
jrgaston 9y ago
Agreed. I read most New Yorker issues cover to cover. Their writers cover a wonderfully-broad range of topics in useful depth. It's the only print publication that I still subscribe to.
- emodendroket 9y ago
  I like the London Review of Books.

24gttghh 9y ago

I still hate printers, and their jams, but I must reluctantly appreciate the engineering behind them after reading this. This seems quite clever: 'Corrugating is when we put an intentional wave in the sheet, like in a piece of corrugated cardboard,” Vicki Warner explained. “It adds stiffness.” The plan was to corrugate the sheet lengthwise by running it over a line of rollers turning at variable speeds before “flying it” into the stacker. If a physical fix was necessary, a part might be 3-D-printed and installed, on-site, by one of the engineers.'

asciimo 9y ago
The challenge helps explain why the user experience for desktop printers hasn't changed much in 25 years.
jeremy7600 9y ago
I have been a part of this process at Xerox.. it works quite well.. I've been involved in a number of different aspects of it as well. I've been the source of some of these fixes, I've been the source of some of the issues, and I've been involved in the investigations to solve them. Xerox has a few different labs for testing different things. The "stub point" is a common thing, and can be very, very difficult to pinpoint. They had one specific finisher that kept jamming when you printed to the top tray. It didn't jam 100%, it was pretty intermittent. Well, this finisher had been in another lab for a few weeks or so and they couldn't find the source of the jams or a pattern to them. I had the finisher installed on one of my machines in the 3 days I'd solved it. There was a small stub of plastic on a flag for a sensor. The flag sits in the paper path, and when its moved, the sensor changes state. So this flag has an pretty smooth surface so as to not catch the paper, but somehow this one got a little nick in it. Enough to cause a jam when a sheet ran right into the nick. I filed it down and the machine never jammed again. We had another issue with a printer at a customer site and the issue dealt with static electricty. a 30kv ESD gun and the inside of a printer.. we still never solved the issue.

zwieback 9y ago

It's even worse in our low-end inkjets, which are made of plastic parts and toy motors and are still expected to duplex-print on the cheapest crap paper imaginable. Our FW devs spend a lot of time perfecting the PID loops and mech sequences to make this happen. But do we get any thanks for that? Noooo... Love that New Yorker article, though. I grew up reading this magazine in the 80s but drifted away. These great articles straddling tech and culture became too few and far between.

jws 9y ago

Exciting fact: Similar jams happen in hot steel rolling mills too. The YouTube videos are just prettier: https://www.youtube.com/watch?v=DVZ1DY0r4y4 https://www.youtube.com/watch?v=DVZ1DY0r4y4 In general the rolling mills call it a "cobble" when a whole or partial bit of steel escapes the rolling mill. Lots of exciting videos.

djsumdog 9y ago
That's pretty insane. Wow, look at those coils of hot metal. It's interested how much of it is still hot after they clear the jam and run it through. I remember years ago hearing about how the US mint misprinted over a million and had to destroy it (and on the Colbert Report, he joked about how them destroy it by burning it in front of poor people). We were talking about it at a party and someone asked, "surely they noticed? Why didn't they shut it down?" An engineer in our group said, "Have you ever been in a factory? It's so fast!" He worked in a toothpaste tube factory where you'd see hundreds of tubes come out every minute. If something went wrong, you'd have to wait for the whole pipeline to clear. Fab shops in China are even more insane. I wonder if the mill would just sell those sheets at a reduced price as low grade/for non-visible construction or if they re-melt them down and run them again.
- rzzzt 9y ago
  Or as a piece of artwork.
- bartread 9y ago
  On the speed front, I concur. Back in 1998, when I was on summer break from university, I worked in a wines and spirits bottling plant. One day the labelling machine started applying wonkey labels to the wine bottles and a couple of hundred had gone through before the guy running the machine had noticed. They weren't wildly misaligned, but far enough from true that we had to wash them off and run them through the line again. Took a couple of us most of an afternoon to sort it out.
  - giarc 9y ago

DubiousPusher 9y ago

I enjoyed the article. Just want to point out briefly that the explanation given in the article of how airplane wings create lift is incorrect. http://www.explainthatstuff.com/howplaneswork.html http://www.explainthatstuff.com/howplaneswork.html

giarc 9y ago
I think they just messed up what side is flat, right?
- DubiousPusher 9y ago
  That's part of it but it's also incorrect to say "the air above moves faster than the air below, and the wing rises." The air speed is not necessarily different. Lift is generated because air is deflected from moving over the top of the wing and thus reduces the air pressure. You can create flat winged aircraft with careful orientation of the wings. Air flow is not like say a spinning disk, where the solid state of the matter forces the outer edge of the disk to move faster in order to maintain relative position.
- aidenn0 9y ago
  No, symmetric airfoils generate lift just fine, and if you were going to spend half your time upside-down, you'd use one. Making it asymmetrical merely makes it more efficient to generate lift in one particular direction (similar to how glasses lenses are asymmetrical to reduce distortion). Furthermore, pretty much no airfoils have flat sides, in nature or in engineering[1] The wing, when placed in airflow, disturbs the air in such a way that the pressure on top of the wing is lower than the pressure below the wing, generating net lift. This isn't a very satisfying description of lift, since it just begs the question of "how/why does it disturb the airflow in such a manner" and the short answer is "we put different shapes in a wind tunnel and measured" with the longer answer being "you don't know enough math to get a good intuition of that" [edit] After reading the article, the article did get lift right for the case of the paper though. Jets of air behave exactly as they say, and you can feel something similar by touching the back of a spoon to the stream of water from a sink; it will get pulled towards the stream of water (or just put a piece of paper on a table and blow over it). A few planes use blown flaps[2] to help get a similar effect (the introduction of a jet of air, which "hugs" the wing helps direct the airflow of the larger mass in the direction you want). 1: https://en.wikipedia.org/wiki/Airfoil#/media/File:Examples_of_Airfoils.svg https://en.wikipedia.org/wiki/Airfoil#/media/File:Examples_o... 2: https://en.wikipedia.org/wiki/Blown_flap https://en.wikipedia.org/wiki/Blown_flap

leandrod 9y ago

Page wide, Precision core.

deleted 9y ago
[deleted]

minikites 9y ago

The "Secret Life Of Machines" episode about the photocopier is also illuminating: https://www.youtube.com/watch?v=S2NIAD5qn7E https://www.youtube.com/watch?v=S2NIAD5qn7E

djsumdog 9y ago
Wow, that's really interesting. I didn't realize that's where the term "blueprint" came from.
joosters 9y ago
Tim Hunkin's TV programs are excellent!

preinheimer 9y ago

I wonder if we could go jam-free with Continuous Stationary ( https://en.wikipedia.org/wiki/Continuous_stationery https://en.wikipedia.org/wiki/Continuous_stationery ). That paper with the holes on both sides from the 80s, and some legacy systems today. It seems really helpful, but I'm not sure which problems discussed it would actually solve.

PotatoMatch 9y ago
Had a dot matrix printer that used continuous paper. Notorious for jamming. Usually something getting stuck on the little holes, or the perforated sides tearing mid-print.
- strictnein 9y ago
  One of my first "tech" jobs was refurbing dot matrix printers after we had them in the field for a while. The amount of little bits of that perforated paper that would get stuck in every moving part in one of those was kind of staggering. People were also really rough on those things. Yanking at the paper to tear it as the printer was just finishing it up.
- Moru 9y ago
  I had several dot matrix printers and can't remember any jams. And I did manage to accidentally dump the whole database to the one at work, the stack was at least 5 cm thick by the time we managed to stop it. It had it's own room though because of the sound so not your normal home printer...
- astrodust 9y ago
  The worst was when it lost traction, shredded the holes, usually in a tangle of paper. There'd also be cases where it kept pulling on the holes but those separated and got gummed up really badly. When you try and tug the pages out they're all perforated so you get, at best, a single page. It can be a lot of work to clear a jam. Most people think of dot matrix printers as slow, lumbering things that would take measurable time to print a single line. The industrial ones, enterprise grade, made by companies like IBM were dizzyingly fast, pages per minute, so if a jam happened it was usually severe. Most had multiple print heads to speed up printing. These also used much wider paper than normal for things like accounting reports. When they jammed, they jammed.

interfixus 9y ago

Many, many years ago I had a student job with a small company doing industrial document finish, enveloping, and large-scale mailings. Apart from a still eaily induced paper eczema, the one thing I took with me was a rather comprehensive facility with the black magic of paper handling. Not an ounce of explicit science in it, but an awful lot of feel: When and how much to air and flex; where a grounded length of copper wire could work wonders; how much or how little moistening to apply, and where; how too touch the stream of paper and somehow know by the feel of the tip of your finger whether something would probably jam within a minute, and which tiny speed-adjustment up or down would probably forestall the disaster; when to to loosen or tighten this or that set of rollers because nightshift and the air getting cooler et cetera et cetera. To this day I never just bang a fresh stack of paper in the printer tray. The full gymnastics of airing, flexing, feeling, airing and flexing again. I'm often laughed at. But my papers never jam!

giarc 9y ago
I've seen people do this before, I always just assumed it was to make sure the pages weren't stuck together, and therefore reduce the chance of 2 sheets being pulled together.
- interfixus 9y ago
  Well, it is, sort of. But in a fast moving production line, it could make a huge difference in jam propensity whether the sheets were fed by somehow with a nice touch or not.
Taniwha 9y ago
In college I worked in an old style (precomputer) printing shop - learning how to work with paper like that is something that never seems to leave you (I always do it when I load a laser printer too)

xefer 9y ago

I'd like to see another article on why in 2018 every meeting seemingly has to start with 5 minutes of fiddling with the screen projector.

sushisource 9y ago
Preach. Seems like someone could make buckets of money undercutting Cisco with a better product
- cat199 9y ago
  in my experience, 4 out of those 5 minutes is a result of apple changing the requisite number and configuration of display adapter dongles every 2 days, with the other 1 minute resulting from from wifi network access policies being innane in most building common areas
shard 9y ago
Is that still a thing? For small meeting rooms (less than 10 people) our offices have large screen TVs (60 inch maybe?), and for larger meeting rooms it looks like there are NEC projectors (I just checked 1). I don't recall a project issue within the last 6 years.
- asterius 9y ago
  Projector fiddling has been replaced with VTC fiddling. I hate Polycom/Skype with a far greater passion than any printer.

reaperducer 9y ago

Coincidentally, just last night I was telling my wife how impressed I am with my work's copier/printer machine. It's about the size of a 1980's copy machine, but my department easily prints a minimum of 5,000 color pages with it each day. Some days it's double or triple that. Sometimes with staples. We go through five massive toner carts each week. They're about the size of a fire extinguisher. In six months, I've seen exactly ONE paper jam. I told her I thought maybe they'd figured out this whole printing thing finally. But I guess TFA says I'm wrong.

mathiasben 9y ago
What's the make and model?
- reaperducer 9y ago
  Don't know the model, but it's a Kyocera. Before this job, I'd only been exposed to that brand as one of the cheap printers for the Commodore 64. I guess it's come a long way!

smacktoward 9y ago

We take sheets of dried wood pulp, stack them so loosely you can always see a few that aren't 100% aligned with the rest, then feed them through a series of unlubricated rollers inside a machine that's usually indifferently maintained and clogged with dust, all while deliberately exposing them to heat and static electricity and spraying their surface with goopy ink or powdery toner. The surprise isn't that they jam occasionally, it's that we ever get anything printed at all!

thisrod 9y ago

I'm surprised that Xerox pays engineers to do all this, when so many companies would pay their lawyers to make it someone else's problem when an odd type of paper stock jammed in tropical weather. Making custom parts and flying out to fit them in production machines? I thought technicians only got to do that during wars. I suppose you might do it when the machine is the one that prints the price labels for Walmart, though.

ocdtrekkie 9y ago
I worked a couple years ago somewhere with iGen printers. Xerox guys were there all the time, absolutely top class service all the way when you're at this level of printing.
Avshalom 9y ago
I don't know about Walmart but here at Target we just use some random small business Epsons for the signing and Zebras (previously Monarchs) for the price strips and stickers
- ComputerGuru 9y ago
  Zebras are indestructible. It’s what Amazon uses in their warehouses for everything. I was looking for a label printer and my options were a new dymo label printer from 2015 or a zebra released 15 years prior. The zebra still won.
  - skrebbel 9y ago
    They're also a lot of fun to code against, if you're like me and have a thing for ancient serial cable text protocols designed by electrical engineers.
    - ComputerGuru 9y ago
      I haven’t coded against the Zebras but I have against their counterparts from Epson with ESC/POC and fully concur. It’s like a throwback to the 80s or early 90s.

alricb 9y ago

> (Before railroads transformed the transportation of lumber, logjams had to be addressed by “jam breakers”—experts who spotted and removed the “key logs” jamming up the river.) River transportation of lumber kept going long after railroads came along. Jam would be broken using dynamite sticks. Here's a movie on the driving of logs on a river in the 1950s: https://www.nfb.ca/film/drave/ https://www.nfb.ca/film/drave/ Driving only stopped in the 1980s on that river.

djrogers 9y ago
Rivers are still in use for moving log booms today - you can see them on the Fraser river and other places in and around Vancouver BC - although they tend to be more orderly, with strict regulations around the logs being properly boomed and contained..
severine 9y ago
Thanks. You reminded me of "El río que nos lleva" (The river that carries us"), a beautiful spanish movie from 1989: http://www.imdb.com/title/tt0098239/?ref_=fn_al_tt_1 http://www.imdb.com/title/tt0098239/?ref_=fn_al_tt_1

GrumpyNl 9y ago

Inst this easy to solve by not feeding sheets, but from a role and cut after printing? Cheaper production and transportation.

Ftuuky 9y ago

I work for a major ICT provider that sells about everything enterprise related, from servers to storage systems, laptops, scanners, etc. In terms of customer support the printers are the absolute worst: usually it's always a critically important since they're used to print the labels for factory outgoing and if they stop for one hour it's millions of euros lost. This means the ticket will be Priority 1 and everything needs to be solved within minutes or else people will freak out since there's a whole factory plant jammed with cars, tires, whatever, that can't leave the factory without the printed stamp.

deleted 9y ago

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