Abstract: A skull vibration device includes: an electrical signal generator configured to generate an electrical signal; an amplifier configured to amplify the electrical signal from the electrical signal generator; a vibration generator configured to convert the electrical signal transmitted from the amplifier to a mechanical vibration; a metal vibration member to which a vibration generating portion of the vibration generator is directly coupled, and which is configured to cover a skull of a human body with a predetermined spacing left between the vibration member and the skull; and a vibration member supporter configured to suspend the vibration member while preventing direct or indirect contact of the vibration member with the human body, and to keep the vibration member at a predetermined distance from the skull. A vibration generated from the vibration member is transferred to the skull through a vibration of air.

Abstract: In a printing device employing a solenoid for driving a printing hammer, provided are switching member for ON/OFF operating electric current flowing through the solenoid coil, voltage generating member for generating voltage in accordance with the electric current, converting member for converting the generated voltage to a digital value, chopping member for comparing the converted digital value with a predetermined comparison value, while for turning on the switching member when the converted value is smaller than the predetermined comparison value and turning off the switching member when the converted value is larger than the predetermined comparison value, detecting member for detecting voltage relating to a driving operation of said solenoid, and controlling member for controlling the predetermined comparison value so as to be varied in an amount based upon the detected voltage. Thus, the current flowed through the solenoid is controlled so as not to be largely varied.

Abstract: In a printing device employing a solenoid for driving a printing hammer, provided are switching member for ON/OFF operating electric current flowing through the solenoid coil, voltage generating member for generating voltage in accordance with the electric current, converting member for converting the generated voltage to a digital value, chopping member for comparing the converted digital value with a predetermined comparison value, while for turning on the switching member when the converted value is smaller than the predetermined comparison value and turning off the switching member when the converted value is larger than the predetermined comparison value, another chopping member for alternatively turning the switching member in another predetermined interval shorter than the predetermined interval, when the set value becomes similar to the comparison value, during said predetermined interval.