A printing head provides an array of stylii and stylii drivers for forming characters in accordance with a desired matrix of dots. Each driver comprises a flat piezoelectric ceramic wafer and a levered beam having a stylus secured to one end and providing at the stylus end a multiplication of the movement of the wafer of approximately 4 to 1 to 7 to 1. The wafers and supporting structure are circular and structured to nest preferably coaxially, with each levered beam lying at a small angle relative to its adjacent beams so that the printing ends of the stylii may be constrained to lie along a straight line perpendicular to the direction of movement of the head.
In a printing hammer which is for use in a printer head and comprises a piezoelectric actuator (16) coupled to a base member (15) by a resilient coupler (23), an arm (19) carrying a printing wire (26), and a first resilient hinge (21) coupling the piezoelectric actuator to the arm, first and second resilient parts (221, 222) are used collectively as a second resilient hinge which couples the arm to the base member. The first and the second resilient parts are both sides of the first resilient hinge on a single plane which has a step of a predetermined size relative to the first resilient hinge in a direction of its thickness. The piezoelectric actuator may be fixed directly to the base member in order to give the printing hammer a high printing speed. Preferably, the first resilient hinge and the first and the second resilient parts are manufactured separately of the arm and/or the base member and brazed in grooves formed in a thick arm end with a spacing of the predetermined size, in a groove formed in an actuator block of the piezoelectric actuator, and in grooves formed in a pair of side legs of the base member. The first resilient hinge may have a T form with the top stroke of the T form brazed in the groove. The first and the second resilient parts may be both branches of a U form.
Printing members comprising a mosaic printing head are driven by flexural bending elements which are electrically actuated to produce a desired printed pattern. The bending elements may take the form of piezoelectric strips or diaphragm pieces which are supported by bearings located at nodal oscillation points of the elements. The printing members when actuated protrude from a bore in one end of a printing head housing. The printing head housing is mounted for transverse movement along guide rails.
An arm for holding the impact stylus of a high speed dot matrix printer is fabricated from a single stamping which when properly folded defines two members having C-shaped cross-sections joined by a thin web. The web is folded around the stylus to bring the 4 legs of the two C-shaped members into overlapping relationship to define a hollow elongated and tapered arm having the stylus substantially wholly encircled by the web whereby after brazing the stylus is securely held.
An electro-pneumatic signal converter, having a piezo-electric bending element (1) which bends when an electrical voltage is applied and controls a pneumatic signal transmitter. The piezo-electric bending element (1) is securely clamped in a sealed transmitter casing (4) and controls an air inlet seating (7) and an air outlet seating (8) which are inserted opposite one another in the transmitter casing (4). In the absence of electrical voltage the piezo-electric bending element (1) bears against the air inlet seating (7), against which it is pretensioned. When a voltage is applied, it separates from the air inlet seating (7) and closes the air outlet seating (8). The respective pneumatic signal is taken off on a signal output (10) which is led out of the sealed space (9) of the transmitter casing.
A high operational speed print head for mosaic printing is provided which has a plurality of print needles positioned on a straight line, each being selectively driven toward a piece of paper through an ink ribbon. The printer head comprises a cylindrical permanent magnet ring magnetized in the axial direction; a circular bottom plate covering the bottom of the permanent magnet; and a plurality of electromagnets each having a center core and a coil wound around the core positioned on a circle on said bottom plate so as to be surrounded by the permanent ring magnet. A yoke provides a closed magnetic path with the permanent ring magnet, the bottom plate and each of the electromagnets. A plurality of moving bodies equal in number to the number of electromagnets are provided, each having at least an elongated armature overlying the core of the related electromagnet and composing a part of said closed magnetic path. A leaf spring supports the armature and is fixed to the yoke, and a print needle is mounted perpendicular to the elongated armature.
