Abstract: A printer includes a switching power supply circuit including a primary side circuit configured to perform a power switching operation, a secondary side circuit having a shunt regulator, a feedback configured to feed a comparison result between the output voltage output from the secondary side circuit and a reference voltage of the shunt regulator back to the primary side circuit to control the output voltage of the secondary side circuit, a control signal circuit configured to input a PSC signal input from an SOC to the photocoupler to control the output voltage of the secondary side circuit, and a switch circuit configured to cut off a current to be supplied to the shunt regulator in a case where the output voltage of the secondary side circuit is a low voltage in accordance with the input of the PSC signal.

Abstract: A printer includes a switching power supply circuit including a primary side circuit configured to perform a power switching operation, a secondary side circuit having a shunt regulator, a feedback configured to feed a comparison result between the output voltage output from the secondary side circuit and a reference voltage of the shunt regulator back to the primary side circuit to control the output voltage of the secondary side circuit, a control signal circuit configured to input a PSC signal input from an SOC to the photocoupler to control the output voltage of the secondary side circuit, and a switch circuit configured to cut off a current to be supplied to the shunt regulator in a case where the output voltage of the secondary side circuit is a low voltage in accordance with the input of the PSC signal.

Abstract: In a head drive circuit for an impact dot printer which performs printing by driving a print wire, a DC power source supplies a power source voltage. A switching element is on/off controlled to apply the power source voltage to a head coil for a predetermined time period. A voltage regulator converts an input voltage having a value higher than the power source voltage into an output voltage having a value as substantially same as the power source voltage. A voltage introducer inputs an inductive voltage, generated in the head coil when the switching element is turned off, into the voltage regulator as the input voltage. A voltage returner feeds back the output voltage of the voltage regulator to the DC power source.

Abstract: For a print head in an impact dot printer, a drive transistor 33 is connected in series to a head coil 59 that drives a print wire, and a pulse 32 is used to turn the drive transistor 33 on and off. Thus, the drive current i is supplied to the head coil 59 to drive the print wire. The input end of a DC/DC converter 2 is connected to the juncture of the head coil 59 and the drive transistor 33, and the output end of the DC/DC converter 2 is connected to the juncture of a power source 34 and the head coil 59. The DC/DC converter 2 clamps, at a constant level, e.g., 90V, the inductive electromotive force of a high voltage that is generated by the head coil 59 when the drive transistor 33 is rendered off. Then, the DC/DC converter 2 transforms the clamped voltage to a voltage equivalent to the voltage level of the power source 34, e.g., 35V.

Abstract: In a head drive circuit for an impact dot printer which performs printing by driving a print wire, a DC power source supplies a power source voltage. A switching element is on/off controlled to apply the power source voltage to a head coil for a predetermined time period. A voltage regulator converts an input voltage having a value higher than the power source voltage into an output voltage having a value as substantially same as the power source voltage. A voltage introducer inputs an inductive voltage, generated in the head coil when the switching element is turned off, into the voltage regulator as the input voltage. A voltage returner feeds back the output voltage of the voltage regulator to the DC power source.