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Is the motor used to move the cartridge a stepper?

Posted: Wed Aug 10, 2011 5:39 pm
by PraveenAlexis
neo, i dissembled a printer and i found two steppers and a normal dc motor (a big one and its not a BLDC) but that normal dc motor was there to move the printer cartridge, i thought that the motor used to move the cartridge is a stepper. still i didnt get the point about motor types :?

how can i find a motor type?? for example stepper motors and BLDC motors

Re: Is the motor used to move the cartridge a stepper?

Posted: Wed Aug 10, 2011 7:17 pm
by Neo
Hello Praveen,

I think You have identified it correctly. There are printers that comes with a DC motor to move the cartridge. However you might have already noticed a thin plastic strip with 1000s of tiny black lines? This is called an encoder. By using a photo-transistor, the distance travelled is measured using this method. Since the measurement is read back in this way, this is referred as a servo system.

Have a look at following images.
Linear encoder:
Encoder_strip.jpg
Encoder_strip.jpg (77.29 KiB) Viewed 7653 times
1 - Encoder strip (semi-transparent gray strip)
2 - Carrier belt (black and brown toothed belt)

Rotary Encoder:
Rotary_Encoder.jpg
Rotary_Encoder.jpg (18.63 KiB) Viewed 7653 times
In printers, the signal from these encoders are read by using a small circuit as below.
encoder_circuit.jpg
encoder_circuit.jpg (31.02 KiB) Viewed 7653 times
Finally a video which tells everything ;)
[media]http://www.youtube.com/watch?v=LQFQ-sCsJWc[/media]

Re: Is the motor used to move the cartridge a stepper?

Posted: Wed Aug 10, 2011 8:43 pm
by PraveenAlexis
Thanks neo :biggrin: