Oki Electric Industry Co., Ltd.

Hirokazu Andou

Mitsuru Kishimoto

Hiroshi Kikuchi

Tatsuya Koyama

Hideaki Ishimizu

Kiyoshi Ikeda

Minoru Teshima

Masahiro Tatsukami

Yoichi Umezawa

Tatsuhiko Shimomura

Noboru Ooishi

Katsuya Kamimura

Tetsuhiro Yamada

Noboru Ohishi

Masayuki Ishikawa

Jiro Tanuma

Masahiko Shimosugi

Takanori Mimura

Hiroshi Sakaino

Toshiro Suemune

Toshiyuki Asaka

Muto Eisaku

Youichi Umezawa

Hiroki Murakawa

An impact printer has a print head in which demagnetizing coils are embedded in a filling compound. A resistor or Zener diode is connected in series between the print head and the printer's frame ground, to prevent current flow through the filling compound from causing corrosion of the demagnetizing coils, while permitting discharge of static charge from the print head to ground.

Impact printer with reduced electrocorrosion using Zener diode for

An impact printer having a print head, the print head having a movable armature, a printing wire fixed to the armature, and sensor for detecting movement of the armature. The position of the armature is monitored based on an output of the sensor. A home sensor detects whether the print head is at a home position. A paper end sensor detect whether a printing medium is between the platen and the print head. A gap motor means adjusts a gap between the printing wire and the platen. A gap controller is responsive to detection signals output by said home sensor and said paper end sensor, for controlling the print head to swing the armature so as to cause the tip of said printing wire to strike the platen, determining a time of impact of the tip with the platen based on the monitored position of the armature, performing a comparison of the time of impact with a predetermined impact time, and outputting a drive signal to the gap motor for adjusting the gap according to a result of the comparison.

Print gap setting in an impact printer

A controller for a dot impact printer has capacitance sensors for sensing the motion of the dot wires in the print head, and a non-volatile, rewritable memory for storing self-adjustment data relating to dot-wire characteristics. A processor controls the driving of the dot wires according to the self-adjustment data stored in the memory. At certain times, the processor causes the dot wires to be driven in a test sequence and updates the self-adjustment data in the memory according to the resulting sensor output. Print quality is thereby maintained for the full guaranteed life of the print head.

Self-adjusting controller for dot impact printer

In a wire dot printer having a wire-dot print head provided with wire drive elements disposed in sequence, the energization of the respective wire drive elements is controlled in accordance with print data supplied for respective drive elements and a drive time signal supplied in common to a plurality of the drive elements. Detection is made, for each drive element, whether or not an adjacent drive element is energized, in accordance with the print data corresponding to the adjacent drive element, and the energization time for the particular drive element is controlled in accordance with the result of the detection.

Apparatus for driving adjacent elements in a wire-dot print head

A print head has a solenoid driving means which employs a filler mixed with a lubricating oil to fix an exciting coil to the core. The filler prevents the layer winding from being shorted due to corrosion of the exciting coil and prevents mechanical abrasion of the armature by supplying lubricating oil during extended operation.

Solenoid actuator

A permanent magnet suitable for use in a wire print head is formed of plural split segments. Each split segment is formed by compressing metal powder in a punching direction in the presence of a magnetic field that is perpendicular to the punching direction. The split segments are combined together into an annular configuration. The permanent magnet so formed is attached to a base, followed by the assembly of a base plate and cores to form a magnet assembly. The base plate and the cores are then surface-finished so as to be flush relative to each other.

Wire print head and process for fabricating it

Wire driving mechanism

Wire dot print head

A wire-dot print head has an armature having a tip to which a print wire is secured, a core provided in confrontation with the armature, a plate spring which is supported in a cantilever fashion and to which the armature is fixed, a permanent magnet assembly generating a magnetic flux to cause the armature to be attracted toward the core overcoming the resilient force of the plate spring, and a coil wound on the core to generate a magnetic flux upon energization to cancel the magnetic flux from the permanent magnet assembly, thereby to release the armature. The permanent magnet assembly includes a first permanent magnet of the samarium-cobalt type, and a second permanent magnet of the neodyminum-iron-boron type or the lanthanoid-iron-boron type.

Wire-dot print head

A wire dot printing head includes armatures each of which is coupled to a printing wire, a felt guide for reducing the friction between the printing wires and a printing wire guide, a residual sheet disposed over a magnetic core frame, a biasing leaf spring, and a oil leakage preventing member. Such member is disposed over the armatures to intercept oil flowing from the felt guide. An erroneous dot printing operation due to the arms of the leaf spring sticking to the residual sheet is prevented.

Wire dot printer head with oil absorbing member

Ink in an ink ribbon contains per 100 parts by weight of ink, 0.1-10 parts by weight of an adsorption-type corrosion suppressor. The adsorption-type corrosion suppressor may be one or more of, the following compounds: amines of the formula R--NH.sub.2, RR'--NH, RR'R'--N (where R, R' and RR' are alkyl groups), thiourea and its derivatives, benzotriazole and its derivatives, thiazole, thioamides and thiosemicarbazide. In another aspect of the invention, the ink contains an organic pigment as coloring material, said ink containing 5.0-10.0 parts by weight of graphite per 100 parts by weight of ink.

Corrosion suppressing ink ribbon

An armature device of a printing head for use in a wire printer includes stylus having a free end to strike a recording medium, an armature connected to the stylus for reciprocating the stylus in a longitudinal direction thereof, a permanent magnet for generating a magnetic flux, a core for conducting the magnetic flux into the armature to form a magnetic path, a coil winding wound around the core for selectively substantially cancelling the magnetic flux, and a spring member having a free end supporting the armature for spring biasing the armature away from the core. The armature has a generally elongated shape, and a transverse groove formed in an end portion of the armature. The end portion of the armature has a first portion forming one wall of the groove and a second portion forming the other wall of the groove, the first and second portions opposing each other along the longitudinal direction of the armature. One of the walls is higher than the other wall. The stylus has a fixed end portion housed and bonded in the groove, with an end surface facing a bottom of the groove.

Armature of printing head for use in wire printer

In a method of producing a movable part of a wire-dot print head comprising an armature supported by a plate spring, and a lever having a tip to which print wire is fixed, the armature and the lever are formed of alloys containing identical atoms or alloys easy to diffuse into each other, a bond part of a base part of the lever is inserted in a bond groove in a tip of the armature, and the lever and the armature are heat-treated in vacuum at a temperature not lower than 1100.degree. C. and below the melting points of the lever and the armature, so that the lever and the armature are diffusion-bonded.

Method of producing a movable part of a wire-dot print head

In a wire dot print head having print wires extending through an opening of a guide nose, the guide nose comprises two halves. The print head may further comprise a wire guide which is fitted in the guide nose and through which the print wires extend, and the wire guide may be clamped by the two halves. In another embodiment, the half members have abutting surfaces provided with semi-circular grooves, which when the guide nose halves are assembled, form guide holes in which the print wires are slidably supported. The use of the two halves facilitates assembly of the print head and reduces noise.

Wire dot print head with a pair of guide nose halves

In a spring-charge wire-dot print head, a support part of a plate spring is clamped, at its outer periphery, between a protruding member disposed on the front surface of the outer periphery of a spacer and a protruding member disposed on the rear surface of the outer periphery of a yoke, and the support part of the plate spring is additionally supported, at the rear surface of its inner periphery, by a protruding member disposed on the front surface of the inner periphery of the spacer.

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Tokyo, Japan

Hirokazu Andou