| 摘要 |
PURPOSE:To suppress a step motor (SM) from its heat generation by performing torque generation far holding a stop position of the SM divided into two methods of stationary torque by a holding current and of no-excitation torque by a permanent magnet of constituting a rotor of the SM. CONSTITUTION:When a control signal Sr of a transistor (Tr) 3 becomes L, an excitation current flows in excitation coils phi1, phi2, to start rotating a step motor (SW). Phase switching control of excitation signals S1 to S4 is performed, and when excitation phase switching is stopped after 6-step rotation, the signal Sr becomes H to stop supplying voltage of a driving power supply V2. Simultaneously, a control signal Sh of a Tr2 becomes L, and a holding current for holding a stop phase flows in the final excitation phases phi2, phi3 from a power supply V1 through a holding current setting resistor 3. Thereafter, the control signal Sh of the Tr2 becomes H to stop the holding current, and the SM is placed in a no-excitation condition and held to a stop position of the final excitation phase before the next start, to perform printing action of a printer. |
