Tokyo Electric Co.

Masami Horii

Kuniaki Ochiai

Takashi Kondoh

Shigeo Komakine

Takashi Norigoe

Hidekazu Ishii

Shinzi Tsuyuki

Osamu Aoki

Takeji Tuchiya

A dot print head includes an armature assembly constructed by providing an armature guide holding a plurality of armatures for swing motion in a cup-shaped housing having one open end, slidably guiding a plurality of print wires attached to the inner ends of the armatures by a wire guide, interposing armature return springs between the armatures and the armature guide, disposing an armature stopper in contact with the backsides of the armatures opposite to the front sides of the same facing the armature guide, and disposing stopper seats between the inner surface of the bottom wall of the housing and the inner surface of the armature stopper; and a yoke assembly joined and fastened to the armature assembly with fastening members.

Dot print head

The present invention provides a compact dot matrix print head comprising a housing internally provided with print wires, electromagnets for driving the print wires, a printed wiring board having a diameter smaller than the outside diameter of the rear end of the housing, fixedly joined to the rear end of the housing and provided with wiring patterns connected to the coils of the electromagnets, connectors connected to the outer surface of the printed wiring board so that the conductors thereof are connected electrically to the wiring patterns, and flexible cables each having one end connected to the connector and the other end connected to a driving unit for driving the electromagnets.

Dot matrix print head

A dot printer head including a housing that contains electromagnets toward its back end, the electromagnets having cores positioned opposite to armatures which are supported detachably against the core. The housing slidingly supports needles connected to the armatures and pushed in retracting direction thereof. An armature stopper made of an elastic substance is fixedly attahced to the inside of a cover which closes the opening at the back end of the housing, the armature stopper being in contact with the vicinities of the free ends of the armatures. A spacer is made of a substance with a linear expansion coefficient such as to ensure the same expansion as that of the armature stopper in thickness, the spacer connecting the inside of the cover to the opening edge of the housing. In this setup, when the armature stopper extends in thickness in keeping with the temperature rise inside the housing during printing, the spacer expands by exactly the same thickness to retract the cover. This allows the armatures to return always to the same position.

Dot printer head

A dot print head comprising a yoke, a plurality of cores formed integrally with the yoke in an annular arrangement in the peripheral portion of the yoke, solenoid coils wound respectively around the cores, armatures fixedly provided respectively with styluses, an armature support supporting each armature at the middle portion thereof opposite to the corresponding core for swing motion, and an armature holding member disposed opposite to the yoke with a predetermined gap therebetween to hold the armatures on the armature support for swing motion. A plurality of joining parts are formed on the yoke on a line on which the cores are arranged, and a plurality of joining parts are formed on the armature holding member so as to be joined respectively to the connecting parts of the yoke in joining together the yoke and the armature holding member.

A dot printer head in which each radially directed armature is urged to pivot about its primary fulcrum in the return direction by a metallic return spring and is urged to pivot in the opposite angular direction by a metallic holding spring. The metallic return springs and metallic holding springs are sized and positioned so that the metallic holding springs exert a torque urging the radially directed armature to pivot in the actuating direction that is lower than the torque urging the armatures to pivot in the return direction.

In printing head of a dot printer according to this invention, a groove having width a little greater than diameter of top end of a needle is formed in front of a needle guide to guide the needle, position of top end of the needle is specified between the bottom of the groove and front surface of the needle guide, when the needle pushes through the printing head it returns rapidly, when top end of the needle is deformed it does not stick to the needle guide, a gauge spacer is interposed between the yoke and the guide holder to be assembled thereby position of top end of the needle is specified, and plural sheets of other spacer are overlaid and removed separately during grinding top end of the needle thereby the needle without deformation at top end can be formed and used for a long time.

Printing head of dot printer

A spring support which receives one end of a needle spring to urge the needle in a reset direction is free to move forwards or backwards. During assembly the spring support is disposed in the top end direction of the needle such that the needle is stable at the inserting state of the top end in the needle guide, after completion of the assembly the spring support is moved rearwards and fixed, and the needle is supplied with a restoring force by compression of the needle spring.

In this invention, the rear ends of the printing needles are bent and prevented from being pulled out by being embedded in needle caps. The needle caps are flat, and the longitudinal directions of the cross-sections of the needle caps are coincident with the radial direction of the printer. The rear ends of the needles are arranged in annular form. Each needle cap is slidably held by a guide body. Lateral displacement of the needles is prevented, and the contacting area between the needle caps and an armature of an electromagnet is reduced. A ring connecting the rear ends of the needles is reduced in size, providing a margin at both sides of the needle cap and armature. The bending amount of the needle is reduced, and the sliding resistance of the needle is reduced, which improves the durability of the needles and the needle guides. Also a small armature may be used, thereby saving on the consumption of power in that an electromagnet of small capacity may be used. The device as a whole is compact, and high-speed printing can be effected.

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Shizuoka, Japan

Masami Horii