Printers: What to do with them?

So over the past few years, printers have gotten stupidly cheap, and cartridges (genuine ones) have remained stupidly expensive. The solution, as any high-printing-volume student would know, is to buy a few cheap printers, and use the cartridges in your existing printer. Or just use the new printer (inkjets will lose a bit of ink to priming the nozzles), along with its new warranty.

In my ethics days, I made long posts about this whole problem and the ethics behind it. The KISS version: It’s dumb, it inspires people to waste, and hides the true cost of the printer.

So now, in most council cleanups and even in some people’s houses, there are stacks of printers just waiting to hit landfill. Perfectly functional printers sometimes.

So okay, today, it’s not quite the case. Today, I am dissecting a printer with “mad printer disease”. These three different outputs all came from the same file, printed with the same settings, three times in a row. My mum likes to call the printer “creative”.

But it was just running down a slippery slope. It lost half its colour nozzles, then the other half, then all of them. A print head would cost an exorbitant amount, and the printer was almost 7 years old. So it was time to retire the trusty Canon PiXMA iP3000.

No self-respecting gadget-guy should throw anything out without at least first trying to fix it. I wrestled with cleaning the nozzles manually, fiddling with the contacts on the print-head, changing cartridges, reinstalling drivers, trying another computer. All the printer-CPR 101 had done nothing to help it.

So one would presume it’d be bin time and that would be the end of that. But hold on a second – whenever you think of binning something, maybe it would be better to open it up and do a salvage – at least you might get some useful parts, and if not, you’d learn more about how something works.

Caution: Exercise extreme care when opening electrical goods. You could get yourself a nasty shock from charged capacitors, you could even cut yourself very badly on sharp parts. Definitely don’t do it while it’s plugged in!

Now not expressly cracking this open for a blog post, I neglected to take great pictures of what happened. Needless to say, basic tools are pretty much requirement 101 – i.e. Phillips head screwdrivers in various sizes, flat-head screw drivers in various sizes, possibly Torx screwdrivers for good measures, pliers and side cutters also useful. Modern screw-less construction techniques take quite a lot of work to get by – some people use a hot knife to break things open – I just persistently pry at the seams till things come apart. If you’re not going to fix it, destructive methods of opening are viable.

So opening this thing up taught me some interesting things:

So, how do printers control their paper so carefully? Well they use slotted optical encoder wheels on the end of shafts. This one had 150LPI printed on it, so I’ll go ahead and assume that stands for 150 lines per inch. It sits between an IR-LED and an IR-photodiode/phototransistor and the interruption of light by the printed lines on the wheel allow for the system to count how far the shaft has rotated. It’s an all-digital system, no analog potentiometer traces etc.

In fact, there were three encoder wheels in the printer itself. A similar system is used for positioning the head-carriage – a film which runs along the print-head corridor:

I took that encoder film out and scanned it – it’s a Ruhlatec made strip:

Canon seems to be quite careful with its component markings for servicing. Most of the components are marked with codes starting with QK1 and QK2, or are remarked with them. Very few items carry their original marking, so it’s a bit hard to identify components and find out their characteristics from datasheets.

Here’s the mainboard, you can see some fairly-decent looking CPU, flash memory to the right, Elpida RAM underneath and in the corner, a Toshiba motor driver possibly:

Not pictured is a self-contained power-supply unit with output of 24V DC at 1.2A which could come in handy. Aside from that, the printer has lots of motors – four in fact, which was a surprise. The biggest one drives the print-head carriage, two of the smaller ones are responsible for paper feeding, and the last was likely to be responsible for disk-printing.

Everything was very nicely connectorized, so you can just unplug the wires that run between things and not have to result in nasty wire-cutting, however, the plugs did need quite a bit of force. But hey, thinking of this as “free” stuff, this could come in handy one day. That’s how junkboxes get populated. Speaking of which, need a spring?

There’s a lot of springs in a printer! There’s more of each sort. There’s also (not pictured) metal bars which are used for the paper rollers and for the print-head to run on which could come in handy as well. Although, here’s one reason that you might not want to take apart a printer:

Remember when you initiated print-head cleaning? Well, there’s actually an ink reservoir where the “wasted” ink goes. In this case, it was a multi-layered absorbent mat material that sat at the bottom of the printer. Even with that, it was still wet with ink, and ink was almost everywhere on the insides. Add the lubricant on the metal bars for the print-head and you can see that your hands will not come off this encounter cleanly. Interesting to note was that this printer could clean its heads either in the “home” parked position on the right, or on the left during a print job. It had an innovative wiper system to clean off excess ink off the print head. There is a lot of ink in the ink reservoir in this printer since some “copy” cartridges had decided to leak quite badly – luckily the reservoir was more than big enough to handle it, otherwise the table which it was resting on would have been hit (my older Canon BJC-240 was dripping ink at the end of its lifetime!)

Still, it was worth it just for a peek. And I’d like to think now that I’ve separated the plastics from the PCBs and other junk, that it would make recycling easier (but I’m not sure exactly whether they would bother). Happy salvaging!

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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2 Responses to Printers: What to do with them?

  1. Sparcie says:

    My Dad and myself have been taking the printers apart to get stepper motors for building robots with. All you need is to get some of the driver circuitry (or build your own) and connect them to an arduino or what ever system you prefer (perhaps a pi can do some). They often have high quality parts that would be expensive if you went to buy them, so they are a good source of mechanical parts as well.

  2. Some Dude On The Interwebs says:

    Or, you know, just buy a cheap Epson or Lexmark laser printer off eBay and use regenerated toner and enjoy printing 8000 pages for two dozen bucks.

    A 8000 page toner lasts me three years.

    Inkjets are stupid, not only because of the razor and blade model.

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