Hitachi, Ltd.

Mineo Harada

Yutaka Kako

Kaname Furuya

Hideyo Tanaka

Tetsuji Shimojo

Kazue Takahashi

Isao Nakajima

Masaaki Fujinawa

Tatsuo Goto

Takao Abe

Kenichiro Takezawa

Tetuzi Simojyo

Kenzi Okuna

Akiyasu Miyazawa

Eiji Tajima

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 print head having magnetic members attracted by a permanent magnet while resiliently deflecting resilient members connected to one ends thereof associated with corresponding solenoids adapted to selectively release the associated magnetic members by cancelling the magnetic attracting force of the permanent magnet, so that the magentic member is actuated by the energy stored in the resilient members to drive printing elements into a printing position. To reduce the moment of inertia of the magnetic member, the magnetic pole surface of the permanent magnet or a yoke mounted on the permanent magnet is contacted with one end of the magnetic member to form a fulcrum for the rotation of the magnetic member. The magnetic pole surface of the permanent magnet or yoke on the permanent magnet and at least the fulcrum portion of the magnetic member are provided with hardened wear-resistant layers formed, for example, by plating with nickel, thereby achieving a higher resistance to wear. The wear of the magnetic pole surface of the fulcrum and of the magnetic member are reduced thereby avoiding non-uniformity of the moment of force in the magnetic members, as well as the resilient force in the resilient members, thereby ensuring a high uniformity of the impacting force applied to all printing elements.

Print head having a wear resistant rotational fulcrum

Two print heads each having a plurality of print elements arranged over a print width to allow printing of a predetermined area by a print scan operation are arranged one for each one of adjacent pages bordered by a seam line of a booklet along which a plurality of sheets of the booklet are bound. The print elements are non-impact type print elements such as thermal print elements.

Booklet printer

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.

Printing head assembly

A print head wherein a magnetic member is attracted by a permanent magnet to bend a resilient member to thereby store energy in the resilient member. A magnetic force of the permanent magnet is adapted to be cancelled by an excitation of an electromagnet to release the magnetic member thereby enabling the utilization of the energy stored in the resilient member as an impact force for printing. A rear end portion of the resilient member is pressed in a direction opposite to a direction in which the impact force is applied by a pressing member and is adapted to pivot with a certain degree of freedom. The pivoting fulcrum for the magnetic member is defined on a magnetic pole surface of the permanent magnet. At least one of the contact portions of the pressing member or the resilient member is provided with a curved surface in an engagement area of the pressing member and resilient member, and a distance between the contact point and the pivoting fulcrum is variable in accordance with the pivoting movement of the magnetic member so that it is possible to provide a control whereby the impact force is constant.

Print head for a dot matrix printer

A dot matrix type serial printer wherein a print medium is printed with indicia such as letters, characters, symbols, or the like by selectively driving a number of print elements while moving a print head having the print elements in a direction of a printing line. To enable the simultaneous printing of a number of print lines in different colors, an ink ribbon is provided having a plurality of tracks in the different colors. The print head includes groups of print elements which are arranged such that the respective groups face and are associated with the respective different tracks of the ink ribbon thereby enabling the simultaneous printing of a number of print lines in the different colors by moving the print head. The ink ribbon is adjustable from a first mode wherein the print elements simultaneously print lines of different colors, to a second mode wherein all of the print elements may be associated with a common track of the ink ribbon thereby enabling a simultaneous printing of print lines in a single color.

Serial printer with dot matrix type print head

A printing head is disclosed in which each attraction member is driven by a magnetic attraction and an impact printing operation is carried out by a strain energy caused by a displacement of a spring member provided on the attraction member. The fulcrum of rotation of the attraction member is defined between the attraction member and a magnetic polar face of a yoke constituting a magnetic circuit together with the attraction member. Means for adjusting the resilient force of the spring member is engaged with a free end of the spring member.

Cancel type printing head

There is disclosed in this application a printing apparatus including small balls of magnetic material prepared in large numbers as printing elements for forming characters or symbols. a wheel having a surface made of ferromagnetic material, a magnetizing head for magnetizing the surface of the wheel to cause the small balls to be magnetically attracted thereto, and an erasing head for demagnetizing the surface of the wheel to remove the magnetically attracted small balls therefrom. As the wheel is brought into pressing engagement with sheets while rotating, images of characters or symbols are formed on the sheets in the form of a pattern formed from a combination of the small balls. The trouble of noise production when printing is carried out can be eliminated because the sheets are brought into pressing engagement with the surface of the wheel while the wheel is rotating.

Printing apparatus

A printer arm for transmitting an impact to a wire stylus in a wire matrix printing head is disclosed. The print arm includes a lever to one end of which the wire stylus is connected. The lever operates in the longitudinal direction of the wire stylus. The lever is a hollow member of a polygonal cross-section and has walls extending substantially in parallel to the direction of operation of the lever. Each of the side wall is provided with at least one through hole for reducing the weight of the lever. The portion of each side wall around each hole is protruded from the other portion of the side wall. This construction effectively suppresses the lateral vibration of the side walls of the lever and to improve the mechanical strength of the lever while reducing the weight of the same.

Printer arm

An apparatus for positioning is characterized by the fact that the circuit for generating a reference velocity, the existence of which is primarily responsible for the disadvantages in the conventional apparatus for positioning by analog feed-back of the velocity, is eliminated and a data processing unit is substituted for this circuit. Thus, the positioning is controlled by a group of predetermined reference velocity values stored beforehand in the memory of the data processing unit.

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Owariasahi, Japan

Mineo Harada