Abstract: The system comprises at least one teleprinter station (1) connected to an exchange (3) by means of a transmission-reception line (2) and comprising a polarity detector (31) for the line circulating current, and a device (30) for reversing the connection of the line wires. If the wires erroneously become reversely connected following maintenance work on a line of single current type, then false call and conversation signals are generated which automatically trigger a checking operation in which the polarity detector is suitably examined under control of a ROM routine E controlling a CPU 84. If the current is found to be the reverse of the correct current, the reversing device is operated in order to reverse the polarity of the connection. In contrast, in the case of a double current line, the reversing device is operated when current is absent in the reception line, thus indicating an erroneous line connection. If the line current interruption is prolonged, a warning device (28) is activated.

Abstract: The device comprises a carriage mobile radially relative to the disk, and on which lower and upper opposing magnetic heads are mounted, each for recording and/or reading a corresponding disk face. The upper magnetic head is resiliently mounted at the end of an arm pivoted to the carriage and is urged against the disk with a predetermined load determined by a spring. A flexible joint enables it to rotate in all directions about a central support. The lower magnetic head is connected to the carriage by means of a pair of parallel leaf springs which enable it to move along an axis normal to the plane of the disk without rotation, whereby both heads maintain good contact regardless of the height of the nominal plane of the disk.

Abstract: A striker mechanism for a high speed serial printer, for example of the daisy wheel type, includes a hammer movable axially towards the platen under the action of an electro-magnet whose armature carries a striker, and against the action of a return spring. Two lubricating felt pads are arranged on opposite sides with respect to the striker hammer and are pressed against the hammer by the grip of a spring for damping the hammer vibrations during the printing cycle. The armature comprises a pivoted lever which is damped with respect to its pivot by means of a felt washer and the lever is damped on return by a helical spring on a rod with a reduced diameter center section where it is struck by a pad on the lever.

Abstract: The device comprises an electrically insulating ink container containing one electrode and a counter-electrode disposed adjacent to the jet nozzle which is laser-bored through the container cover plate. The two electrodes are excited by a voltage pulse such as to generate a spark between the ink meniscus and the counter-electrode, and to expel a plurality of ink particles, rather than a single blob. The ink can be kept in circulation between the container and a reservoir 51 by means of a pump. The meniscus can be kept outside the nozzle by means of a second nozzle coaxial to the first, or by a suitable arrangement of the ink hydraulic circuit. In the case of magnetic ink, the meniscus is pulled back by a magnetic field. The ink can also be brought in front of the nozzle by capillarity.

Abstract: The printer comprises a solid or liquid ink jet head 100 arranged to print open dot at a time on paper running over a platen 80. The head is carried by a carriage 48 movable transversely with simple harmonic reciprocating motion. In order to reduce the effect of inertial forces when the carriage reverses its movement, the drive is effected by an eccentric peg 70 on a disc 276, the peg engaging in a guide slot 54 of the carriage perpendicular to the direction of reciprocation. An eccentric cam track 71 in the disc engages a peg 92 on a counter-weight 90 for counterbalancing the inertial forces of the carriage. In order to synchronize the printing operation with the carriage movement, an optical strobe disc 258 is rigid with the disc 276 and has slots 258 disposed at a pitch varying according to the harmonic motion. The platen 80 is rotated intermittently by a helical cam 277 carried by the disc 276 and a peg wheel 280, 281 .

Abstract: A printing device comprising a printing head having 18 wires actuated by a corresponding number of control electro-magnets for writing on a recording support symbols and characters in conformity with dot matrices. The writing ends of the wires are aligned along a single line, the slanting of which relative to the direction of movement of the carriage is variable. With the writing ends vertically aligned the height of the 18 wires is equal to that of two lines of writing, as a result of which it is possible to print two rows of characters simultaneously. By inclining the head and suitably selecting the speed of movement it is possible to print a line at a time with high definition dot matrices.

Abstract: A wire printing head of ballistic type comprises a front guide fixed to a carriage and in which the printing wires are mounted in an axially slidable manner. The electromagnets for actuating the wires have their respective cores mounted inside a tube of non-magnetic material. In order to obtain high heat dissipation, the electromagnet cores and windings are embedded in a resin block which fills the interior of the tube. The exterior of the tube is also provided with a set of cooling fins.The electromagnet armatures are mounted on a rear cover which is connected by a screw to a part of the front guide, which in its turn is housed in a compartment in the resin block. Shims are disposed between the front guide and group of electromagnets, and their number can be varied in order to modify the distance of the ends of the printing wires from the platen.

Abstract: A serial printer comprises a carriage 32 movable parallel to a platen 14 and on which there is mounted a printing device 31, for example of the daisy wheel type. The guides 23, 25 on which the carriage slide are mounted on a frame 20 which can turn with respect to the fixed sides of the machine on pivots 16, 17 to allow easy replacement of the daisy wheel. A motor 70 located beneath the roller constituting the platen effects displacement of the carriage along the writing line by means of a steel cable 72 and a series of return pulleys 44, 45, 75, 82. The cable passes through coaxial holes 74, 84 in the pivots of the frame, in such a way that its conditions are not altered when the frame is turned. A unidirectional clutch 86 and a spring 89 coupled to one end 88 of the cable maintain the tension in the cable always constant, while providing a non-yielding anchorage when the motor pulls on that end of the cable.

Abstract: The tracing element is carried by one vertex of an articulated parallelogram, of which the arms are constituted by thin steel or glass fibres associated with a plastics coating or matrix for damping vibrations. The arms are moved by servocontrols constituted by electromagnets with moving coils having a length less than the length of the corresponding magnet pole piece. The coils are formed from a conductor of square or rectangular cross-section in order to provide maximum packing for the turns.

Abstract: An optical transducer for determining the angular position of a rotating member relative to a fixed structure, comprises a notched disc 13 rotatable inside a support housing 12, a light emitter 18 and a plurality of photovoltaic cells 19 for detecting the passage of light through the disc notches. The active and passive elements of an electronic circuit connected to the photovoltaic cells are carried by a single ceramic plate 21, which also acts as a support for the cells 19. The circuit comprises trimming resistors in the form of films deposited on the ceramic plate and connected to the amplifiers by the photovoltaic cells. In order for the signals generated by the amplifiers to have constant, predetermined peak values, the values of the resistors are trimmed during the production stage by means of a laser which selectively burns away parts thereof. The ceramic plate 21 is cemented on to the transducer housing 12, which is then positioned on the laser apparatus.

Abstract: A serial dot matrix printer is of the non-impact solid ink type has the ink 102 contained in a tubular container 100 provided at one end with a printing orifice 106. In order to facilitate replacement of empty container, the container is provided with a grip 103 fixed to its central zone, which fits into the space between two resilient fixing forks 95, 96 rigid with the printer carriage 48. The end of the container remote from the orifice 106 is closed by a cap 110 which engaged by an electric contact 116 and connects to the ink rod 102 through a spring 107, for establishing the operating voltage between the ink rod and a counter-electrode 89 in the form of a laminar spring guiding the paper 82 round a platen 80.

Abstract: In a typewriter a carriage spacing mechanism is mounted on a support element to space a paper bearing carriage independently from a base structure and is connectable for assembly of the machine to a control means supported by the base structure. Keys, intermediate levers and type basket are assembled independently from the base structure and are fixed to the base structure only through the medium of a supporting block for the keys and fixing means for the type basket. A plate picks up the striking movement of the type bars and comprises a plurality of bearing elements disposed so as to cause the plate to rock about two pivot elements of the bearing elements and a cam portion which is dimensioned so as to regularize the stroke of a transmission element in dependence upon the particular type bar actuated for the striking.

Abstract: The electronic typewriter comprises a character-carrier disc with flexible blades, which is mounted on a carriage which is movable transversely with respect to the typing roller by means of a stepping motor. Mounted on the carriage is a motor for selecting the character, a striker hammer, a positioning device and an actuating motor which actuates the hammer and the positioning device and which also provides for activating the operations by means of a typing ribbon and by means of a correction ribbon. The selection motor is supplied by a servo control of digital type which imparts to the motor a speed which is proportional to the positional error, positioning the blade of the character to be typed with a maximum error of .+-.1/4 of a pitch. The positioning device then provides for correction of the character, engaging a recess of a positioning disc which is synchronous with the character-carrier disc.

Abstract: The cartridge comprises a container in which a feed spool 22 and a take-up spool 24 for the ribbon 19 are rotatable. The cartridge is provided with a lateral arm 14 which guides the ribbon between the container and the typing zone 23 and with a distance piece 25 between the container and the arm 14 which disposes the ribbon above the typing point 17 at a higher level than that of the container in order to allow viewing of the characters along the typing line. The distance piece 25 comprises deviation surfaces 56, 57 which constitute a friction device for the ribbon emerging from the container.

Abstract: The head is composed of a series of electrically conductive elements in one or more rows, which elements are selectively subjected to a high potential relative to the coacting electrode.The elements have a thickness of less than to 50.mu. and a pitch less than 100.mu.. The elements may be disposed in a plurality of rows on a cylindrical, rotatable head.In a modified embodiment the elements are disposed on the edge of a plate, in a row extending over the length of the line.

Abstract: The printer comprises a ROM recorded for each character with a set of pairs of numerical instructions, of which one represents the direction of a constant velocity vector of the tracing element for tracing a segment of the character, and the other represents the duration for which that velocity has to be applied to said element. The direction instruction is decoded by a decoder in order to generate two orthogonal components which control two servo-mechanism by way of two corresponding D/A converters. The duration of the movement is controlled by a counter loaded by the duration instruction and decremented by a clock signal. Every time the counter is emptied a logic unit responds by addressing the next byte in the ROM.

Abstract: A cartridge for an inked ribbon for type bar typewriters comprises a container adapted to be mounted on one side of the printing point and a terminal part which guides a length of ribbon to the printing point and reverses the direction thereof for reentry of the ribbon into the container. Two return surfaces of the terminal part carry the ribbon reentering the container back at the same height as the emerging ribbon. The container is of elongated shape and is mounted removably on a support on the machine which rocks in front of a platen in such manner that the terminal part of the cartridge is disposed below the printing line. There is provided a mechanism for actuating the inked ribbon which comprises a control element actuatable by the type bars and a toggle joint which rock the cartridge support for effecting a precise raising of the ribbon in response to variable stroke control actuated by the selected key.

Abstract: A selector system for a typewriter of the single type carrier kind, in which a series of stop members are selectively positionable in order to cooperate with two selector levers in such a manner as to effect the variable displacement of the type carrier for the selection of the character which is to be printed. A control member releases the selector levers for their operation by driving forces and comprises a cyclic resetting member which returns the selector levers to their position of rest against the action of the driving forces on completion of the typing of the character selected. A shift device for the type carrier comprises a cyclically operating drive mechanism adapted to operate a member kinematically connected to the type carrier for the selection of one of the two zones in which the characters are distributed.