Inkjet printer positioning system?

[Charlie1138]

I am trying to hack my printer.. I am planning on replacing the brain of the printer with a new circuit board to control the stepper motors.

But I am wondeirng if it would be useful to use the printers positioning system so I could make it's movements super accurate. It has these clear plastic sheets with tiny little markings that seems to be read by somekind of reader. There is a long tape one on the plane the printer heads slide.. and a round one on the motor that feeds the paper. Would it be possible to make my own circuitry to use them?

Maybe if I take a picture of the curcuit board someone here would understand how it works? Or be able to give me some clues?

[Admin]

I theorize those are linear encoders.

Not entirely sure . . . but see if there is a sensor close to these strips.

Pic! I am curious . . .

[Charlie1138]

I think you  are right.. linear encoders sounds like it. I love this site!

I will post pictures soon to show you what it looks like. It has very very fine markings.. you can't really see the gaps with the naked eye, I don't think. just looks solid grey.

How much is one of these "digital counter IC" things?

Also.. it says these linear encoders aren't very accurate because of errors.. I wonder how the printers get around this? If the printers weren't very accurate the image would be all screwed up, right? So they must have some way to deal with it?

[Charlie1138]

Here are the pics of my printer. I need to still take some close ups  of the circuit board. They loooked closer when I was taking them..

http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer1.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer11.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer12.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer13.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer16.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer15.jpg
http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer14.jpg

[Admin]

That transparent wheel with the markings is the super high resolution encoder. The black thing covering the wheel is an IR detector, basically counting the black tick marks when the IR light is blocked.

Unfortunately the circuit board wont be hackable, and is useless.

I am guessing you want to hack the printer to do high position stuff, but with your own controller right? All you do is plug the IR sensor signal line into a digital output of your controller. Use interrupts, timers, and a feedback PID control system. You then have the microcontroller control a motor driver to actuate the DC motor. Its fairly trivial in terms of work required, but implementing a control system for your first time takes a little while to understand. But definitely a simple project so I dont think you will have that much trouble.

If you plan to scrap the printer, these are usefull things I see that you should save:
gears
belts
IR sensor
encoder wheel
DC motor
wires
springs
screws
ceremic capacitor
ribbon cables

[Charlie1138]

Thanks Admin!

What I basically want to do is make it controllable through the USB port. Then I want to basically use it as it is.. and add some hardware to it then mess around with it and write a program so it does the same thing repeatedly. Kind of like a anamtronic robot at PIRATES OF THE CARRIBEAN.

What about power supply? Is there some way I can use the power supply chord that the printer uses? Or would it be better to get a different hobby type power supply?

[Admin]

for a microcontroller you want 5V, and for the motor you want a separate supply at im guessing 6-ish volts.

the printer power supply should be able to handle it . . . check with a multimeter and see what it outputs . . .

the IR sensor probably takes 5V too, just check . . . you might be able to look up the part number written on it.

[Charlie1138]

Thanks again! I'm excited! This is a fun beginner project.

[Charlie1138]

Does anyone know what these black plastic things are on the side of the printer? They have somekind of little hash marks on there for aligning something. There is one on each side of the printer head slide. They seem to be adjustable. IS this just somehting the people sue when they manifacture the device? To help them align it when it is being built.

http://img.photobucket.com/albums/v221/Dr.Gonzo1138/printer1.jpg

[Admin]

uuhhhh no idea . . .

what if you poke it?

haha ok i mean does it rotate, or is it attached to anything? your theory sounds better than any of my guesses . . .

[Charlie1138]

haha

Yeah, they rotate, but they don't seem to do anything when they rotate. Very strange..

Is there somekind of rule in engineeering where they intentionally try to confuse people who attempt to take somthting apart or repair it? It seems like the same thing with cars, too. Everythting is counter to common sense it seems.

[Admin]

lol

only if your microsoft . . .

[Charlie1138]

 

[HDL_CinC_Dragon]

lol

only if your microsoft . . .

burrrrrn... I kinda hate MS lol but at the same time im almost forced to love em


Are you sure they dont do anything internally? They dont perhaps tighten tension on a belt or anything like that?

[paulstreats]

oct 24th 2006

  I hope he'd have sussed it out after all this time: