I'm looking at some components of an inkjet
Does anyone know why it uses an optical encoder on the scroller shaft? Doesn't the shaft rotate by a step whenever the print head reaches the head? Why is there a need for the printer to keep track of the number of mechanical rotations?
Best Answer
The printer in your photo uses brushed DC motors, not steppers. You can vary the supply voltage to a DC motor to control its speed, but the actual speed will vary depending on loading so you cannot set the position that way.
Encoders are required because that is the only way the controller can determine the position of the mechanism.
DC motors are used rather than steppers because they are faster, more powerful, more efficient and cheaper.