Abstract: Ink for an ink jet printer comprises a microdisperse three-phase system having two liquid phases and one solid phase, the pigment. The ink exhibits a high indelibility and a low tendency towards the formation of microprecipitates.

Abstract: The ink detecting device gives advance warning of the end of the ink in a reservoir or cartridge feeding an ink-jet thermal print head. The device comprises a pair of electrodes that are immersed in a spongy, ink-soaked body contained in the reservoir, and are arranged in a region adjacent to the feed duct at which the spongy body has a 30% to 100% higher capillarity than in remote regions. The electrodes are connected to a bridge circuit which measures the electrical resistance of the ink between the two electrodes.

Abstract: An electronic typewriter has an electronic control circuit housed with the usual typing mechanism in a casing, and can be provided with a display module for displaying text and/or machine functions. The display module is removably fixed to the casing. An electronic unit for controlling the display module is removably fitted in the casing and is connected to the control circuit and the display module by connectors. A basic typewriter without a display module can be constructed with a cover instead of the display module. The two types of typewriter can be produced on largely the same production line, and the basic typewriter can be simply upgraded with a display module in the field.

Abstract: An electronic typewriter (11) has a line spacing device (29) for rotating a platen roller (16) and a transport device (28) for moving a printing carriage (19) in both directions. The line spacing and transport devices are driven from a single motor (32) via an intermediate gear (40) mounted on a shift member (35). The shift member (35) is displaceable between two operative positions for connecting a driveshaft (33) to the transport device (28) or to the line spacing device (29). A servomechanism (36) which is motorized by the shaft (33) displaces the shift member (35) between the two positions by means of a shift electromagnet (81) which actuates a lever (79) to lock the gear (40) by means of teeth (88) on a slide member (43). Positioning means (44) hold the shift member (35) in each of the two operative positions, and an electronic control means (22) controls the motor (32 ) and the electromagnet (81). The system is of low cost, and is simple, functional and reliable.

Abstract: A unitary cassette for a typewriter comprises a container and two arms. The container comprises two support elements and which project from the bottom and which are capable of rotatably supporting a supply spool and a take-up spool for a correction ribbon. Two guide elements projecting from the ends of the arms guide a portion of the ribbon below the typing ribbon, and a tensioning device holds the ribbon taut. The cassette can be mounted on a carriage of the machine by means of two projections projecting from the underneath of the bottom and which are capable of being pivotally mounted in two respective grooves and moving against two co-operating surfaces for oscillating movement about an axis parallel to the roller. A pin on one side of the container can be removably engaged into a seat of a connecting lever of the machine, which is connected to a displacement means.

Abstract: A feed arrangement for a typing ribbon and/or a correction ribbon comprises a linear motor having a coil-carrying slide which is movable with an alternating rectilinear movement, a toothed wheel for the feed movement of the ribbon, and a connecting mechanism interposed between the coil-carrying slide and the wheel for converting the movement of the slide into a unidirectional rotary movement of the wheel for advancing the ribbon. The connecting mechanism comprises a first lever which is moved by the slide and two mutually independent ratchet assemblies and which are capable of alternately engaging with two diametrally oppositely disposed teeth on the toothed wheel. The ribbon is carried by a cassette and the wheel rotates a blade capable of engaging into a seat in a feed roller of the cassette.

Abstract: An electronic typewriter has a reduced number of electrically-powered actuators and comprises a motor powering a differential motion transmission unit having first and second output members. Transmission control means powered by a solenoid moves a slider to engage stop members selectively with the first and second output members to permit the second and first output members respectively to rotate. The first output member drives the carriage transport mechanism. The second output member drives the character carrying element and also powers function devices, namely a correction device, through a motion switching mechanism controlled by a switch control mechanism including another solenoid. The typing ribbon feed is driven by reciprocation of the slider between its two states. The motor is mounted on the frame and drives the motion transmission unit on a carriage through a belt; it also drives a line spacing mechanism through a clutch operated by a further solenoid.

Abstract: In a thermal ink jet print head the ink is expelled in the form of small drops through a plurality of nozzles communicating with corresponding expulsion chambers for expulsion of the ink through the effect of rapid heating of heater elements contained in the expulsion chambers. The nozzles, the expulsion chambers, the heater elements and the associated electrical conductors are constructed in a plurality of metal layers and insulating layers supported by a silicon plate. The plate is fixed to the structure of the head and is supplied with ink contained in a movable cartridge fitted to the structure of the head. The cartridge comprises a rigid reservoir containing a sponge saturated with ink which can be hydraulically connected to the head by means of a needle-type conduit mounted on the head and which perforates a rubber membrane of the cartridge.

Abstract: A body structure for a printer comprises a front cover and a rear cover and is capable of accommodating a platen roller a typing device and advance means for advancing and feeding individual or continuous forms. A hinge element fixed to a pillar of the body structure permits pivotal movement of the covers and such that the front cover can rotate from a first operating position in which it is parallel to and supported on the body structure to a second operating position in which it is substantially turned over onto the rear cover to permit access to the platen roller and the typing device. In addition the hinge element permits the rear cover to rotate from a first operating position in which it is substantially parallel to and supported on the body structure to a second operating position in which it is substantially inclined with respect to the body structure. The forms can be supported and guided by the outside surface of the rear cover in both operating positions.

Abstract: A striker device for use in printers comprises a platen roller, a character-carrying disc and a print hammer for striking a character of the disc against the roller. The print hammer is actuated by an armature which is movable in an impact direction by virtue of electromagnetic excitation of a stator body. The device includes strike-silencing means comprising sliding guide surfaces between the print hammer and the armature, which ensure freedom of movement for the armature with respect to the hammer in the impact sense and direction, and a ring of elastomeric material which is interposed between the armature and the print hammer and which transmits the kinetic energy of the armature to the print hammer with a delay. Particular ratios between the masses `Mh` and `Ma` of the hammer and the armature and between the levels of hardness `Kr` and `Kp` of the elastomeric ring and the roller provide a single but prolonged strike on the part of the print hammer.

Abstract: Two rollers with lobes for feeding a sheet are disposed below the plane feed surface. The two rollers are rotatable on axes perpendicular to one another and move the sheet or the document to be printed in a direction perpendicular and parallel, respectively, to the printing direction of the head to align the sheet against retractable stop elements movable parallel to the printing direction and against a lateral guide perpendicular to the printing direction. Suitable optical sensors detect a possible misalignment of the sheet and cause a further rotation of the rollers to complete the alignment of the sheet against the guides; in case a document such as an accounting book is to be fed, a testing device detects the thickness of the document for positioning the head at a prefixed distance from the printing surface of the document itself.

Abstract: A cassette for a printing ribbon for typewriters comprises a casing accommodating a supply spool, a receiving spool and a brake and take up device which operates on a tube of the supply spool and on the ribbon which is unwound from the supply spool. The tube is rotatable on a sleeve projecting from the bottom of the casing. The brake and take up device comprises a shoe for applying a braking action to an internal surface of the tube. A wire spring has an intermediate portion which engages in a seat of coupling means of the shoe. In a first position the shoe is urged against the surface of the tube and brakes the supply spool. In a second position the shoe is spaced from the internal surface of the tube and the supply spool is free to rotate. The spring also performs the slack ribbon take-up function and for that purpose comprises an end having an L-shaped bent portion which in turn is engaged with the ribbon to regulate the tension and unwinding of the ribbon which is unwound from the supply spool.