Citizen Watch Company, Ltd.

Yoshimasa Tai

Makoto Yasunaga

Tetsuya Yamamoto

Takashi Moriya

Tsutomu Ikehata

Katsuya Masuda

Hirofumi Suzuki

A printing head includes solenoids arranged in an annular array for driving needles which are arranged in a zigzag array of two vertical columns. Solenoids corresponding to needles forming one of the columns are arranged on a semicircle of the annular array in the same order as that of the needles on the needle column. Two solenoids respectively corresponding to needles disposed at lower ends of the two needle columns are designed to generate magnetic fluxes whose directions are the same. During underline printing where these two solenoids are alternately energized, the magnetic flux generated by one of the solenoids never acts to increase an effective magnetic flux of the other solenoid at an initial stage of the excitation period thereof, so that the needle of the first solenoid reaches its forwardmost position at an appropriate time. The needle is rapidly restored and its tip prevented from being caught by the ink ribbon. After the forwardmost position is reached by the needle associated with the first solenoid, the magnetic flux generated by the second solenoid never acts to increase the magnetic flux of the first, permitting rapid restoration of the needle.

Printing head using staggered arrangement needles

A dot matrix double print head including a front actuator and a rear actuator is disclosed. Each actuators has a print wire unit in which a plurality of print wires are slidably mounted, a plurality of electromagnets, and a plurality of armatures corresponding to the number of electromagnets. The length of the armature of the rear actuator is smaller than that of the front actuator, and thereby the moments of inertia of each of the armatures and print wires of both the actuators approach each other.

Double print head

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Tanashi, Japan

Yoshimasa Tai