Printer and DC motor speed control device

In speed control that is performed within a single operating cycle of a printer, three-level control of ON control, OFF control, and chopper control, is performed in place of the two-level control of ON control and OFF control, to effectively suppress speed variations due to load variations within a single operating cycle, even in small printers provided with DC motors having small output torques. In a printer comprising a DC motor 7, a paper feeding unit 5 that includes a paper feeding roller that uses the DC motor as the driving source, and a printing mechanism unit 2, for printing, in use of the printing mechanism unit 2, onto paper that is advanced by a specific amount by the paper feeding unit 5, an encoder 10 for outputting pulse signals according to the rotation of the DC motor 7 is provided. The encoder 10 is provided with a pulse forming region for forming a pulsed signal, on the periphery of an encoder plate, where this pulse forming region is provided with a non-uniform spacing region in a section within a uniform spacing region.