EEVblog

Teardown Tuesday.
What's inside an office photocopier? Dave only needs a screwdriver to find out...

[@abellujan66]

"Don't turn it on, take it apaaart!" ... immediately turns it on.

[@christophschmeler2744]

He even wore the proper shirt...

[@frankreiserm.s.8039]

I am an old TV/VCR repair tech., and today I have an interview for a job to repair copiers. Thanks for the review, you have prepared me for my interview.

[@hadireg]

I went late to work because of this teardown :) I had to finish watching all the amazing smartness and beauty inside this copier! Thanks Dave! cheers

[@Clell65619]

Late to the party, but as an old copier tech, just a few notes. There is no 'secret harddrive' for capturing every copy the machines scan. If there was, it would fill up somewhere around the 1000th copy. There are digital copiers with integrated HDDs but you have to specifically tell the machines to archive the images There is a security feature on digital copier, that integrates machine identifying serial numbers into each image. The LED array you pulled off the Drum assembly frame is not for cleaning the drum, at least not really. The drum assembly has a cleaning blade to remove remaining toner from the drum prior to it rotating in front of the LED array, known as the Quenching array. The purpose of the LED is to neutralized the charge on the drum surface prior to it turning to the corona wire (which reapplys the charge). Basically the digital image is formed on the drum in the following sequence: 1. cleaning blade removes remaining toner 2. Quenching LED neutralize drum surface charge 3. Corona wires apply negative charge to the drum 4. The Rotating Mirror array throws the image on the drum, w/ light portions of the image imparting a negative charge to the drum 5. the drum rotates past a 'magnetic brush' which allows positively charged toner to come into proximity with the drum, with the positive toner coating the negatively charged portions of the drum. 6. drum rotates to fact paper, the paper is more positive than the drum, pulling the toner off the drum onto the paper 7. paper runs through fuser, and the toner is fused into the paper via heat and pressure 8 customer doesn't like the image (usually because they never clean the copier glass) and place a service call, where they spend most of the tech's time listening to them complain about the copier.

[@chrizizdaman]

Clell Harmon Thanks for information! I have been trying to learn the parts and how they work. I deliver copiers and anytime we pick one up from a doctors office or government facility the hard drives have to wiped. I have been told that machines today can keep millions of past print jobs on the drives?

[@Clell65619]

***** Like I said, there are digital copiers with integrated HDDs, but you have to tell the machines specifically to store a copy A quick check of the current corporate industry standards have the higher end units with three terabyte drives (some of the more absurd ones are actually installed with RAID arrays to ensure the images are safe) Millions of past copies? No. Not on any one machine 10s of thousands would be pushing it.

[@EwanMarshall]

Clell Harmon I know from the security side that the buffers often keep the last x number of pages in network printers, I'm sure it's the same with digital copiers that work in a similar way. It eventually cycles over the buffers but some of them are rather large. So you may be able to get the last week's worth of data or so out depending on usage. But it's not infinite of course.

[@Clell65619]

Ewan Marshall Not on a copier of this vintage. The image isn't really 'digitized' in any meaningful way. It's a straight through path from the optics to the organic drum, with only a minimal delay through the logic array. This model of copier does have memory, but only few pages worth (up to 20 if I recall correctly), and its plain old fashioned dynamic ram. Which means the ram reinitializes each time it's powered up... or the next duty cycle. Modern stuff, sure, you need to be careful. These >15 year old machines, not so much.

[@EwanMarshall]

Yeah, I know, but you'll be surprised, that said, solid state buffers can be a problem to. And we have ways to maintain data through a power cycle of DRAM which takes hours for the data to naturally degrade fully and longer with tricks like the use of liquid nitrogen to cool it. Most computers do not actually wipe the memory on initialization just when they want to start using that page. Yes, it depends on the model as to how much of an issue it is. Finally, often a business the machine is never fully shut down so over the weekend a network attacker can often get to those buffers. Ideally one wants to be able to store the whole document in the buffer these days (scan once then correctly collate copies of multi-page documents, so those buffers have gotten bigger (to hundreds of pages these days) but even 20 pages can be a problem if that is medical records, bank records or financial statements.

[@bt410382]

i translated a lot of photocopier manuals in the past and i worked with technicians. so i should say that you missed some good stuff. those solenoid driven clutches control the shaft they are connected to. when you fire the solenoid, the free running gear engages. the point is, you don't have to put several motors and synchro them electronically. One big motor turns the entire gizmo. most modern laser scanner head (that six sided mirror thing) has a ceramic bearing which has a real tight tolerance. you can lift it and replace quite easily, however. fuser unit has a VERY powerful halogen bulb and ptc's and thermistors inside. toner dispensing unit has a very complex measurement algorithm which regulates the toner/developer (ferrite material) ratio electronically. one last word: maybe you noticed, you can not connect a wire to a wrong socket, they're all different in the entire machine. i especially noticed this with Japanese copiers.

[@smokeajayson]

The six sided mirror thing is a polygon mirror motor.

[@epd807]

Great video Dave! Thank you for taking the time to make it! Im lovin Teardown Tuesday!

[@robertbauer6723]

Wish I could give multiple thumbs up for all the work you put into making this one. Thank you.

[@malanvogt]

I repaired copiers for quite some time. Your quite off on how the entire thing works. Fun to see someone discover the difficulty of repairing these.

[@jaideep1337]

So hard to imagine the amount of work that goes into building one of these. Even the mechanical systems were very complex. Thanks for the video Dave.

[@msk19991]

That is one of a kind Tear-down. Absolutely INTERESTING till the last minute. Many thanks for your efforts.

[@WooShell]

oh man, I wish I could dive through whatever dumpster you throw your teardown output into ;-) there's such a lot of cool stuff in that copier alone that I'd love to reuse for some of my projects..

[@MrNadirzenith]

You are spot on with a lot of the parts and their functions you were guessing. For future reference, use cold water to remove the toner ;)

[@SoCalFreelance]

Those precision machined metal cylinders are some of my favorite parts. Wipe the toner off them and gawk at their shiny goodness.

[@phillipfeltz7738]

As a copier tech of almost 20 years. you made me cringe. With every part I was yelling what it is. I hope this video opens some eyes as to what it takes to be a great copier tech. Customers always think copiers are simple. I love your videos, thank you.

[@catthecommentbothunter6890]

Man do you still have those?

[@brotherlu]

Best teardown yet. Thanks Dave, one of the best channels on KZbin.

[@SargeZone]

back when i worked in electronic scrap, i was the one who always got all these copy machines cause none other wanted to mess with them. we had to completely seperate all bits into various bins, alu, iron, plastics, wires and all that. i had fun ...

[@darthrevan2063]

jens jorgensen I would love to do that

[@charlesmiller5078]

Try to get a old Satellite to tear down that would be interesting. I repaired and programmed large business phone systems for 30 years, one day our copier screwed up in the office, we called a repair tech, We were really impressed on his knowledge of copiers, he had the thing torn all apart due to some cog out of alignment. But he got it repaired and it went on working for years after. Electronics repair is one thing having to align and adjust and troubleshoot just where the trouble is coming from is a whole different story. I believe my boss offered him a job before he left. Repair techs truly are talented people and are very hard to find, and must combine many, many skills. At our company new techs had to work with there trainer for 5 years before they were cut loose , some more some less. That laser scanner reminds me of the scanners where you check out in a store, almost the same design. Great hack material for sure. Interesting tear down, tho you did it many years ago, its timeless. Now go sell the scrape metal :)

[@MinnoW12]

I hope to see a detail tear down of the PCBs. Thanks for the great tear down Dave!

[@metrofan1000]

"Dave only needs a screwdriver to find out..." Well, no he need's a drill too. Jesus, this monster contains at least a thousand of screws...

[@__-mu1xd]

I think we have improvements in CAD to thank for ever-more-complicated gadgets. Back in the day designers had to somehow force an extra dimension onto paper to make sure everything fit. Now that third dimension fits so neatly into the two of the computer screen, you can pretty much stick anything in there. And so now my radio makes coffee for no reason.

[@Indigo8086]

Protip: don't use even remotely lukewarm water when cleaning toner off of your/your things. Use ice cold water and it should come right off

[@Teknopottu]

This I got to remember. Going to disassemble two big copiers at some point.

[@Francisco-j1e]

Not even halfway and am already very impressed how complex that machine is.

[@youpoofoowoo]

I'm a mechanical engineer and lead laser printer development for over 20 years. I began watching EEVBlog recently so allow me for such a super late comment. I enjoyed this video very much. You first thought clutch as motor but later you discovered what it is by yourself. And you did no know this is full digital copier at first but you found the right answer by yourself at the end. You really got great insight of engineering. Now, what I felt interesting was that you were very impressed seeing the main drive unit that comprises of one big DC motor and gears and clutches. Actually drive unit is not very difficult unit to design. Designing itself is rather straight forward and easy. While control panel with LCD and touch screen , that you were not interested in, rather impresses me, a mechanical engineer, more.

[@RalliArt001]

Thanks for the bit of Nostalgia. I used to work on this model just over 10 years ago :) The little motors are electro magnetic clutches.I'm happy to answer any questions (might be a bit rusty on specifics for this model)

[@sandy1653]

And people wonder why the good ones of these can cost as much as $30,000.

[@Good0Music0for0you]

That was very satisfying lol !! Taking electronic equipment appart mmmm. Hi from London . Love you post Dave .

[@6417893265q784256128]

Thanks a lot for do such much work and share with us , very cool !!!

[@proofesur]

WTF you know what we say at the EEV blog; DONT TURN IT ON take it apaaaaahrt. 2 second later. and i powerd it up here. XD WUT

[@soundfxasmr]

co co combo breaker LMFAO! I was about to comment the same thing! XD

[@excite236]

co co combo breaker I think everyone who watched the video was ... WTF!!!

[@AakeTraak]

+co co combo breaker Unacceptable! Unsubscribed!

[@kev4241]

+co co combo breaker that was just a first step in investigation to get started with tear down

[@DMack6464]

Comedy in a nutshell.

[@Wolfeman4sure]

As someone who fixes this exact model of copier on a close to daily basis, this was fun to watch. Your pretty close for the most part about how everything works. Bravo.

[@JamiePineappleWyatt]

When i was working as a photocopier technician I had to build atleast 10 machines from scraps during training, we had a shed we called the graveyard, filled with 100's of busted machines, managed to build all ten machines from the bottom up and have them calibrated to a T. great experience, never forget the pain and suffering it caused me though :'D in hindsight I wish I raided that shed for so many more parts haha

[@eidorianaladannet]

I've done a few teardowns on a few really old photocopiers - 90s vintage - cogs and chains! They weigh a ton, take ages, but lots of great bits :)

[@EEVblog]

Always good to find new audience market segments!

[@glenthemann]

Why? Because we can. - hahaha, the look on his face and the way he said that, I love this dude

[@aserta]

Gears, motors, parts, plastic bits, boards. Man no one should pass the opportunity to tear one of these down. I've done quite a few, older ones. It's gritty but man the fun is worth it.

[@walikai]

I fully disassembled one like this in high school electronics, got tons of useful parts!

[@squawkBirdies]

I love your voice, Dave. Your enthusiastic "Take it apaarht!" is hilarious!

[@albear972]

Now the real fun stuff is to try to put it back together :P The carry handles are standard equipment on all copiers. I worked in that biz 10 + years ago.

[@WafflesASAP]

You are a brilliant, brilliant guy, Dave!

[@somon90]

This video is as old as the photocopier was back then now.

[@chancerogers5757]

I love his voice and hate it as well 😂

[@00Skyfox]

Looks like your photocopier time machine got hit by a train! I had fun years ago scrapping a small desktop copier and got a ton of salvage parts out of it.

[@Chooseyouruniquehandlebyaddin]

funny, im rewatching your videos and i just noticed. You turned it on right after you said "Don't turn it on, take it apart" hahaha

[@SirDeanosity]

***** He pronounced it "apaaat".

[@sal4]

Jeez, such a HUGE machine lol, Thanks Dave, this is awesome!

[@MatthewSuffidy]

Love this tear down Just rip everything out, no turning back!

[@gastonlutri]

Hi Dave.... in minute 11:24, they are not motors, are clutches... normally there is only one motor.

[@okovermekeamglight4563]

If i tear that down i am going to need a bigger screw container.

[@ogvhsarchive]

"don't turn it on, take it apart" * turns on photocopier *

[@umeramir]

thank you Dave... It would be really nice if your can shed some light on how these electromechanical systems are actually designed and built... maybe a small DIY project from start to end..

[@pepe6666]

holy cow dave that was an effort. man that was fascinating and an adventure. awesome

[@mechlabman]

Just a note about the clutches, they are spring wound clutches. Copier manufacturers have been using the since 1969 (I was working on these machines back then). There is a coil spring surrounding the shaft inside these things and the little metal plate floating on the end is pulled in toward the electromagnet to make it clutch. The plate is tied to the end of the coil spring and causes the spring to wrap tight on the shaft causing the gear and shaft to lock up. When the coil is de-energized the spring unwraps and the clutch freewheels. Some guys call these 'Chinese handcuff' clutchs for an obvious reason. Godfrey

[@nicholasbodley2238]

Wrap-spring clutches go back many decades. Perhaps the Model 15 Teletype used them. The Friden Flexowriters definitely did. They often drove the load by one revolution and then disengaged. The ones I knew had springs wound with square or rectangular wire. They were lubricated, (but not likely with extreme-pressure oil!) When disengaged, the spring was held expanded to minimize wear. One end of the spring put some torque on the outer sleeve (spring inside), which was stalled by a pivoted pawl that was pulled out of engagement by an electromagnet. Power to the magnet released the sleeve, the spring contracted, wrapped, and gripped the continuously-rotating inner cylinder. Left by itself, the spring gripped the sleeve inside it. If the e. magnet stayed energized, the sleeve continued to rotate, and the spring didn't slip. If the magnet's power was cut off, its pawl-armature was ready to snag an outward projection on the sleeve. That made the spring expand, and the driven member stopped. However, inertia made the driven member overshoot slightly, and another pawl and "one-tooth ratchet" kept it from going backwards. That kept the spring expanded, minimizing wear. The driven shaft always stopped at exactly the same position. Incoming power rotated the cylinder inside the spring. Cylinder rotated on the output shaft, which extended the full length of the clutch. We called these single-revolution wrap spring clutches. They worked extremely well The Model 28 and later such Teletypes and the IBM Selectric typewriter used a different type of clutch, which had a few pawls inside a shallow cup with a cylindrical inside surface. Those clutches also had a pawl to "stall" the load and disengage the clutch. Cup drove the load. Releasing the first pawl used driving torque to engage another pawl, and as I recall, that second pawl made a third engage. The clutch simply did not slip! Stalling the first pawl made all three(?) disengage. HTH!

[@rbaleksandar]

Grab the soldering iron and start tearing down the PCBs. :D Buttons, LEDs, transformers, resistors, capacitors etc. can all be reused. :)

[@davidtaylor5007]

Unbelievable the amount of Engineering that went into creating that thing! Then think about sub-component contracting, manufacturing, Q/A, and field support!! Amazing they weren't $500K/ea back in the day. And at home I have a ink-jet printer that cost $29US and replacement cartridges (B/W and color) cost ~$60...cheaper to buy the printer than the ink cartridges. Yeah, its not a scanner/FAX/networked but it prints what I need. Great tear-down Dave!

[@mikeselectricstuff]

Don't hoover up that toner unless you want to redecorate the place - toner is smaller than the holes in hoover bags!

[@PackratCND]

SWEEEEEEEEET ! hardware, hardware, hardware ....Love it. Next is the Space Shuttle !

[@hydrolisk1792]

PackratCND Next week we take apart the NASA control room lol.

[@ZAJBEISTE]

Interesting vjdeo! I have teardowned a photocopier once to steal some engines... I also was amazed how comlictated machine it is. Thanks to your video i can understand more how it works. And also i had bad time with the black toner :).

[@SamGallagher]

14:09 Hey I know some of this stuff. The high voltage power supply generates at least two different outputs, both can be as low as 800V (dark surface voltage of PC drum) or up to 8 kV e.g. for a corona wire/scorotron. One output for the photoconductor drum (PC drum) and another for charging the paper. The outputs are DC biased with a smaller AC bias for even more charge distribution. 21:57 So, most drums aren't made of selenium anymore, they use other photoconductor materials. They are split into a very thin charge generation layer (CGL) and a charge transport layer (CTL), with materials like PVK:TNF. Really, photoconductor materials are a hot topic in electrophotography (the technical name for laser printing, copying, etc). Hope this helps!

[@bocatablanco]

EPIC protocopier teardown Good video, thanks!!

[@whiskeyify]

That was pretty amazing to see what's inside a copy machine. Growing up I often wondered how things work like for example a telephone. I got hired by AT&T and became a tech and so got to work inside Central offices where all those Switches are...I also installed stuff at customer locations and spent time outside in the field testing cable pairs.

[@Aussie50]

excellent teardown! I have a Samsung all in one copier unit to do the same to, damn their fun to rip into :D

[@pikaonyoutube2139]

Tbh a drill with a bit for the screws really helps with the scrap time i got 1 recently and within a day i had it scrapped down to bare bits 3million screws 😂

[@plattcriceta1719]

Safety shoes comes in mind.;) Nicely done; very educational, but still fun.

[@robroberts1473]

Hey dave thanks for all the vids love watching someone with a passion for what they do!

[@electricsnut]

The flywheel is there to help stabilise the rotation of the drum and stop image abnormalities due to minute changes. Those smaller units in the paper feed section are drive clutches, quite common to have a single drive motor and clutches to engage drive to seperate sections. The HV unit can are quite high in voltage, our machines run in the order of 6000v for the transfer stages. Need to get you one of our retired colour machines with a transfer belt to tear down!

[@HamishMilne83]

My mouth was agape for the whole 48 minutes. Great job :)

[@msylvain59]

This race for the Ultimate Teardown is more and more challenging. This time you won thanks to the item size criteria, but Mike and Tesla500's are still dangerous competitors. Unless a spy satellite or a UFO falls in your backyard, you will need to find some very very serious stuff to win the game. A Magnetic Resonance Imager, an electron microscope or a DNA sequencer should be damn strong inputs in order to winthe Ultimate Extreme Teardown contest.

[@ExtantFrodo2]

notice the shaft that you pulled the clutch off. The gear spins all the time driven by that first motor. The clutch alternately connects the gear to the shaft to spin the shaft at your discretion.

[@stefaneinarsson7223]

Thank you very much. I am seeing this the second time and still have many questions.

[@HazeAnderson]

#303 ... sure wish this one was a teardown of a Roland TB-303! Never too late ... 😂

[@aserta]

Advice: keep all the screws if you still have them. These are pretty high quality screws.

[@youme20000]

I'd enjoy watching the rebuild video as well. Perhaps Dave could post a time-lapse in case I don't have a whole day to watch it.

[@8bits59]

45:41 Need extra screws? Take apart your boss's old decommissioned photocopier!

[@8bits59]

+Noah Keck Or extra motors, sensors, gears, transformers of every shape and size, heck pretty much everything you might need hidden in that darn thing

[@rbaleksandar]

The problem I'm having with such machines is that often there is literally no information to be found online about those, which accordingly often renders them useless (especially if you don't have the right testing equipment to get the specs). The mechanics however are spot on an you need no datasheet for looking at a set of cogs and how those rotate. :)

[@gamerpaddy]

they get sold really cheap these days... got 2 used ones for 1 buck each, just have to pick them up. i hope to retrieve some useful parts from it.

[@deweys]

There's so much cool stuff in this thing I'd love to get my hands on.

[@iammeok]

"Don't turn it on, take it apart" "... and I powered it up here" XD

[@God-CDXX]

YOU CAN WASH YOUR PARTS WITH DISH SOAP AND WATER

[@WVCapsfan]

I tore apart a Mita DC 4090 with the collator last year and it took me almost two weeks - All e-clips and screws - not a single hex bolt. Sold the plastic gears and Tsubaki timing/drive belts on eBay for almost $30. Got almost $20 for the scrap sheet steel minus the steel rods which I am saving. All the motors and clutches test good. There are some really good stepper motors in there!! Stocked up my electronics project parts. A lot of work but worth the effort. Excellent education project.

[@wgblondel]

"not on the cockpit kiss alright you know it's already all over the damn being end act unite I hate" thank you auto generated subtitles :D

[@EEVblog]

+William Blondel Gold!

[@picketf]

+William Blondel Australian is a hard to understand language XD

[@8bits59]

+William Blondel And I thought text to voice was bad, heck voice to text is even worse :D

[@scottiebones]

William Gerald Blondel it's really not that bad, I can understand him fine..

[@ethanthecraftwars]

I have a 3d printer and I think normal printers are much more complex now...

[@Allan-mf1he]

hehe as a copier tech your encounter is funny. The HV is from 1K Volt up to 50K Volt on some machines. One of the best machines in its time.

[@zenoist2399]

If you don't know what it is , call it a mechanism.

[@TimberTechWorkshop]

I got the exact one for free and took it a part too! lots of great useful parts, took me a while to take it apart ..

[@hydrolisk1792]

Very awesome, I would like to locate a 80's copier like this, bet there would be loads of tech and such inside one of those :)

[@DandyDon1]

The only problem with older machines is the supplies, consumables and parts, which are not always easy to find.

[@t0ny747]

I wanted to seem him put it back together afterwords!

[@mattgring]

the little board is your temp/humidity sensor. The machine corrects for that also.

[@theburningrectumofvengeance]

+EEVblog @ 25:20 The small board with the device looking like a speaker is actually an off-the-shelf ambient humidity/temperature sensor.

[@billyproctor9714]

I just came across this older vid. of yours as I was searching for some information on some components that I just recovered from a 7 year old brother machine that took be 7 hours. I had a blast doing it think of all the uses I could come up for all this neat stuff. I thought the same as you, where to start if some came to you with all the parts and said make it work?? Cheers, Billy, Canada

[@dsier]

Great video! Just wanted to concur with everyone else ;) The CCD is usually between one and three rows high, this type of device is also called a linescan or line camera. They are often used for quality control in industries. The reason for the two different "arms" with mirrors is for the distance between the lens and the paper to remain fixed, quite clever :)

[@erixmix]

those hidden handles are for a finisher (the two you show) and the others are for a high capacity external paper tray

[@ziz1000]

Youre awesome, Ive been waiting for a show like this. Thanks!

[@Elfidinn]

Basic operation of a Digital photo copier. Paper are picket up with rollers then its going to the registration roller where it is synchronize with the drum speed. The drum and developing roller are charged negative to 600 volt , next step is writing a latent image on the drum with a laser where will the toner stick to the drum, next paper are passing by the drum and is charged with a positive charge by the transfer roller to attract the toner. and the last step is the fusing unit pressing the toner with rollers and heat of 190 degrees Celsius.

[@theantipope4354]

Those "flat motors" with the 2 blue wires aren't motors, they're electro-magnetic clutches. Machines like this typically have one big motor (the one on the PCB in this case) powering the drive train that does the paper handling, with clutches to enable the various stages in the sequence, eg; paper pickup from the current tray, etc. ETA: Heh. At 17 minutes, he's finally twigged that they're clutches. :)

[@ondraster]

Man, I took apart SO many photocopiers... and they always sport so much different electronics! Some have ARM cores, some have ASICs...

[@PrimalEdge]

awesome tear down! I'd love to see you test that laser.

[@MrDubje]

Whatever you use to clean your hands with, do it with COLD water as warm water fuses the toner to your hands.

[@mikeselectricstuff]

25:20 could be a humidity sensor

[@BedstyBiggs]

Great thx for this tear down. Whoa that was quite interesting.....

[@FrontSideBus]

You should have a look inside of the Oce Jetstreams that I play with at work! A3 continuous feed in full colour duplex at 150 meters per minute! They cost several million each!

[@bjtaudio]

Incredible and advanced engineering. It just a dream to be able to design something like that, and its an awful lot of pains taking design work right down to the plastic moldered panel controls.

[@deathblowhere]

Awesome vid! Thanks Dave! You should tear down some old multichannel reel-to-reel recorder with micro controller (some like a Studer A800 or A827) - I know it would be crime bit it'd be hella a tearing down!))