A compact electro-magnetic oscillatory actuator was proposed based on a pair of torsion springs for optical scanners operating at low oscillating frequencies, such as 50 Hz for a portable barcode scanner. Each torsion spring in the actuator is made of silicone rubber and is dually supported at both ends. A yoke is coupled with the driven coil to enhance the driving torque of the actuator. In this study, we analyzed the effect of the yoke on the resonant frequency of the actuator, as well as the torsion moment. We also experimentally determined the relationship between the resonant frequency and the magnetic gap of the yoke. Compared with the mechanical resonant frequency in the experiments, which was designed to be 50 Hz, the frequency was modified to 57.4 Hz, 54.7 Hz and 52.9 Hz when the gap between the yoke and the permanent magnet was 1.5 mm, 1.7 mm and 1.9 mm, respectively. The proposed actuator, which combines a yoke with flexible torsion springs, is potentially useful as a compact optical scanner, taking advantages of both low power consumption and high reliability. Y. Bu et al. / Magnetic spring characteristic of an oscillatory actuatorwhere J was calculated to be 1.46× 10 −9 kg/m 2 using 3D modeling software.

In this paper, we propose a high-speed moving magnet-type oscillatory actuator in which a dual-mover structure is designed to reduce magnetic damping force. Both movers have independent resonant frequency, and the actuator is driven at the larger resonant frequency. The smaller mover serves as the optical scanning element and maintains large oscillation amplitude. The larger mover, with moving magnets, serves as the magnetic driving element and maintains relatively smaller amplitude because of the magnetic damping.Index Terms-Actuator with dual movers, high speed oscillation, magnetic damping, optical scanner.

�Yinggang BU (Mem.), Kaname INOUE (Stu. Mem.), Kazuaki OYAIZU, Hideyuki KINJO, Akihiro NITTA, Shintaro YOSHIDA, Tsutomu MIZUNO (Mem.), Toshiki MARUYAMA, Tomoki TERASHIMA Linear DC Motors (LDM), used in office automation equipments (OA) such as line printers and image scanners, are required to be with high acceleration and fast-response. Under the condition of limited power supply capacity and an outside dimension, we investigate the structure of LDM to make the acceleration rise most quickly by using finite element method. In this paper, we examine the single-supported and double-supported LDMs. Target of acceleration, direct current and response time of acceleration are 490 m/s 2 , below10 A and 0.15 ms. As a result, double-supported LDM's maximum acceleration is 655 m/s 2 and response time of acceleration is 0.36 ms, so the target is not achieved, but comparing to single-supported LDM, response time of acceleration is less than 0.59 ms.

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