SERIAL PRINTER, METHOD OF DETECTING CARRIAGE POSITION, METHOD OF DETECTING CARRIAGE SPEED, METHOD OF DETECTING SPEED OF PAPER FEEDING, SPEED DETECTING DEVICE AND METHOD OF DETECTING SPEED

摘要

PROBLEM TO BE SOLVED: To detect a moved distance and a direction of a carriage with high accuracy. SOLUTION: This printer has an image pickup device 20 attached to a carriage 66. The image pickup device 20 comprises a CCD sensor 2121 for picking up an image of a top face of a printing paper 22, a CCD driving circuit for driving and controlling the CCD sensor 2121, a noise removing circuit 23 for removing a noise included in a signal generated by the CCD sensor 2121, an A/D converter 24 for converting a signal outputted from the noise removing circuit 23 to a digital signal, a signal processing circuit 25 for applying various signal processing operations to the A/D converted digital signal, a lens 26 for imaging the image of the printing paper 22 on the CCD sensor 2121, and a focus adjusting section 27 for adjusting the focus of the lens 26. As the image pickup device 20 can read fibers of the printing paper 22, it is possible to detect a moved distance and a moving direction of the carriage 66 with high accuracy.