Retrotechtacular: The Incredibly Difficult Task of Copying a Document

It seems hard to imagine, but in the early part of the 20th century, there weren’t a lot of great options for creating copies of documents. The most common method was to use carbon paper to create multiple copies at once from a typewriter or a line printer. All that changed with a company called Haloid. Never heard of them? They later became the Xerox company.

The underlying technology dates back to 1938 (invented by a physicist who was also a lawyer). In 1944, they produced a practical copier and shortly thereafter sold the rights to Haloid. The Haloid company originally made photographic copy machines that used wet chemistry.

In 1959, the Xerox 914 (so called because it could copy a 9″ x 14″ document) came on the scene (that’s it, below). The 650 pound copier could make seven copies per minute and came with a fire extinguisher because it had a tendency to burst into flames. If you didn’t want to spend the $27,500 price tag, you could rent for only $25/month (keep in mind that in 1959, $25 would buy about 25 pounds of T-bone steaks). You can see a commercial for the 914 in the video below.

Xerox_914

In the commercial, you’ll see them make a big deal out of the fact that the print was dry. That’s because a lot of previous machines used actual photographic processes with wet chemistry. Obviously, that also took special paper.

Even Further Back

If the copier didn’t exist until recently, how did people make copies before? Turns out there were lots of ways to make copies of varying degrees of bad quality or extreme trouble. In some sense, the best copies were made by scribes just writing down a second copy of things. There were a variety of machines that would capture what you wrote and make a copy by mechanical or other means. A polygraph (not the lie detecting kind) allowed Thomas Jefferson to write letters and make a copy. The machine moved a pen to match the movements of the author’s pen, thus making a near perfect copy. With a few adjustments, this became the pantograph which not only does the same job, but also can shrink or enlarge the copy. Carbon paper was widely used to make multiple copies of handwritten and typewritten documents.

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Push Button, Receive Bacon.

Members of the Rabbit Hole hackerspace spent the last weekend competing in The Deconstruction, a 48 hour hackathon competition. The hackerspace’s theme was “Light it up!”, so members created some awesome projects involving light. The star of the show was their bacon cooking machine. The Rabbit hole made the “Push Button. Receive Bacon” meme real.

A broken laser printer was gutted for its drive train and fuser assembly. Laser printer fusers are essentially hot rollers. The rollers melt toner and fuse it with paper as it passes through the printer. The heat in this case comes from a lamp inside the roller. That lamp also puts out plenty of light, which fit perfectly with the team’s theme.

The Rabbit Hole members wasn’t done though, they also built a pocket-sized infinity mirror from an empty Altoids tin. The bottom of the tin was cut out, and a mirror glued in. A filter from a broken projector made a perfect half silver mirror, and some LEDs completed the project.

The members also built a fandom art piece, consisting of 25 fans connected together in a skull shape. The eye and nose fans were lighted. When the fans were plugged in, they kicked for a few seconds before spinning up. Once they did spin though – there was a mighty wind in the Rabbit Hole.

Click past the break for The Rabbit Hole’s Deconstruction video!

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OpenExposer, The DIY SLA Printer

printer

Precisely applied ultraviolet light is an amazing thing. You can expose PCBs, print 3D objects, and even make a laser light show. Over on the Projects site, [Mario] is building a machine that does all of these things. It’s called the OpenExposer, and even if it doesn’t win the Hackaday Prize, it’s a great example of how far you can go with some salvaged electronics and a 3D printer.

The basic plan of the OpenExposer is a 3D printer with a small slit cut into the bed, and a build platform that moves in the Z axis. The bed contains a small UV laser and a polygon mirror ripped from a dead tree laser printer. By moving the bed in the Y direction, [Mario] shoot his laser anywhere on an XY plane. Put a tank filled with UV curing resin on the bed, and he has an SLA printer. Put a mounting bracket on the bed, and double-sided PCBs are a cinch.

The frame is made of 3D printed parts and standard RepRap rods, with the only hard to source component being the polygonal mirror. These can be sourced from scrounged laser printers, but there’s probably some company in China that will sell them bulk. The age of cheap SLA printers is dawning, friends. Video below, github here.

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Toner Transfer PCBs, Double Sided, With Color Silkscreen

Silk

Making a few PCBs with the toner transfer method is a well-known technique in the hacker and maker circles. Double-sided PCBs are a little rarer, but still use the same process as their single-sided cousins. [Necromancer] is taking things up a notch and doing something we’ve never seen before – double-sided PCBs made at home, with color silkscreens, all make with a laser printer.

For laying down an etch mask, [Necro] is using a Samsung ML-2167 laser printer and the usual toner transfer process; print out the board art and laminate it to some copper board.

The soldermasks use a similar process that’s head-slappingly similar and produces great results: once the board is etched, he prints out the solder mask layer of his board, laminates it, and peels off the paper. It’s so simple the only thing we’re left wondering is why no one thought of it before.

Apart from the potential alignment issues for multiple layers, the only thing missing from this fabrication technique is the ability to do plated through holes. Still, with a laser printer, a laminator, and a little bit of ferric or copper chloride you too can make some very nice boards at home.

Modifying a printer for PCB fabbing

ohgodmyeyes

The migraine-inducing image above is the product of [Rupert Hirst]’s attempts at home PCB fabrication. He’s using the toner transfer method – printing a circuit on a piece of transparency sheet with a laser printer, setting it on a piece of copper clad board, and sending the whole assembly through a laminator. It’s a fairly straightforward process, but if you can’t run a transparency sheet through a printer multiple times your etch resist won’t hold up too well. Of course the transparency sheet must be aligned each time it goes through the printer, so [Rupert] came up with a modification that ensures laser toner goes only where it’s supposed to.

[Rupert] picked up a Samsung ML-2165W laser printer for his PCB fab shop, but printing the same image multiple times on the same transparency sheet would result in unusable masks. This problem was fixed with a few plastic shims used to hang door frames and a card stock tray that ensures the transparency sheet goes through the printer the same way every time.

We saw [Rupert]’s homebrew PCB fabrication process a few weeks ago when he sent in his six channel floppy drive MIDI synth. In his build video, [Rupert] demonstrated what is possibly the cleanest toner transfer PCB we’ve seen to date. You can check out his etching process in the video after the break.

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Separating a working scanner from its broken printer

The laser printer portion of this all-in-one machine gave up the ghost and [Entropia] couldn’t get it working again. But the scanner was still functioning so he decided to separate the scanner from its dead printer module.

The model in question is a Samsung SCX-4200. The design is actually perfect for separation because the scanner sits on top of the out feed tray of the printer. It can even be lifted to allow more room for printed pages to pile up. All he has to do is separate the hinged connector and reroute the flat cables. But the real question in [Entropia’s] mind was whether or not the control board would work without the laser printer components connected to it.

He carefully disassembled the unit, spilling toner here and there which is left over from a catastrophic knock-off toner cartridge incident. A quick test showed him that although the drivers complain that the paper tray is open, the scanner does still work. He glued the controller board seen on the left to the bottom of the scanner enclosure, and added some felt feet. Now his scanner is closer to the size you’d expect. And on the plus side he gained a geared stepper motor, laser scanning unit, exhaust fan, and a couple of solenoids to use in future projects.

Resetting the page count on a laser printer

[Brian] really liked his Samsung color laser printer right up until it was time to replace the toner cartridges. A full set of toner cartridges sell for about the same price as the printer itself, so [Brian] figured he could simply refill the toner in the cartridges he already has. The printer sends out the ‘low toner’ warning  based on page count and won’t print if the page count is too high, negating the economy of a toner refill kit. Luckily, [Brian] figured out a dead simple way to reset the page count so he can use those third-party refill kits.

All the configuration settings and page counts for the printer are stored on an I2C EEPROM. After dumping the data held on this EEPROM with an Arduino and sniffing everything going into the EEPROM with a Bus Pirate, [Brian] was nearly at his wit’s end. Thankfully, serendipity intervened. When [Brian] restarted the printer with the Bus Pirate attached, he noticed it took much longer to initialize. Printing a configuration report, he was trilled to see that all page counts have been zeroed.

The final hack that allows [Brian] to reset the page count and used refilled toner cartridges is a simple wire that ties the SDA line of the EEPROM to ground on boot. [Brian] used a momentary switch, but given this is a once-every-few-months operation, a simple wire would suffice. Check out [Brian]’s page reset demo after the break.

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