Hitachi, Ltd.

Tetsuji Shimojo

Mineo Harada

Kaname Furuya

Hideyo Tanaka

There is disclosed an improvement upon a cancellation type printing mechanism or a stored energy type printing mechanism having magnetic members, so-called armatures, attracted by a permanent magnet while resiliently deflecting resilient members connected to one end thereof. The magnetic members are associated with corresponding electro-magnets which are adapted to be energized selectively to release the associated magnetic members by cancelling the magnetic attracting force of the permanent magnet, so that the magnetic member is actuated by the energy stored in the corresponding resilient members thereby to drive the printing elements. One end of the magnetic member contacts the magnetic pole surface of the permanent magnet or a yoke mounted on the permanent magnet so as to form a fulcrum for the rotation of the magnetic member. A recess is formed on one side of the magnetic member facing a core of the electro-magnet, so that the magnetic member does not engage the corner of the core of the electro-magnet. According to this construction, the magnetic member is prevented from striking against the corner of the core.

Printing mechanism

A printing head assembly having a permanent magnet to attract magnetic members such as armatures to store the strain energy in resilient members such as leaf springs, electro-magnets to cancel the magnetic flux generated by the permanent magnets in order to drive the magnetic members, first yokes related to cores of the electro-magnets, and second yokes forming surfaces by the permanent magnet and serving to form fulcrums of rotation of the magnetic members. The permanent magnet is mounted on the first yoke and the second yoke is mounted on the permanent magnet respectively. In order to equalize attracting force by the permanent magnet among a plurality of armature actuating mechanisms and to adjust the height of the surface of the second yoke, with a predetermined height, there is applied a powdery magnetic material mixed into a bonding agent on at least one side of the permanent magnet. This bonding layer can also absorb some errors caused by the production of the first and second yokes and the permanent magnet.

Growing community of inventors

Woariasahi, Japan

Tetsuji Shimojo