Abstract: An ink jet printer has a chamber for the evacuation of gases which form during the printing operation, the chamber having an associated Venturi pump acting as a vacuum source.The electrical energization circuit for the printer includes an adjustment member for effecting controlled variation in the energy of the pulses which cause the ejection of ink sprays through the printer nozzles.

Abstract: A print head (15) on a carriage (16) slides on a carriage guide bar (17) in front of a platen bar (18). A receipt slip (25) is fed from a roll (26) over part of the width of the platen bar (18) to a knife (40) for cutting off individual receipts. A daybook slip (45) is fed from a roll (46) over the bar (18) to a take-up roll (50). Other documents may be fed in for printing either downwardly between upper guides (37 and 38) or upwardly between lower guides (35 and 55). In either event the inserted document is engaged by a drive roller (60) and pressure roller (70) to be positioned at a predetermined height, under control of photodetectors (80 and 81). The pressure roller (70) is mounted between levers and can move away from the drive roller (60) to accommodate the thickness of the inserted document. The levers also support the carriage guide (17), whereby the head (15) is positioned a constant distance from the surface on which printing is effected.

Abstract: The typing arrangement includes a character-bearing member of the "daisy wheel" type, the symbols of which can be printed at the point of printing either alone or in the form of combinations of successive strikes of certain symbols for constituting a font of printable characters and other symbols which is appreciably greater than the number of symbols on the daisy wheel, and adapted to meet the printing requirements of all the graphical symbols derived from one common alphabetical stem. Each printable character has an individual code which is recognizable by the control circuits of the arrangement which put into operation one or several printing cycles using selection of the symbol or of the symbols on the daisy wheel which make up the character and the displacements of the daisy wheel associated with the printing of the various component symbols.

Abstract: An electronic circuit for control of a stepping motor (11), and in particular for damping the oscillations of the rotor thereof, comprises a digital-analog circuit (14) which, using a signal proportional to the angular speed of the rotor, which is taken off on one of the windings of the motor (11), provides a signal (SMR) to the control circuit (12) supplying the windings, so as to modulate the current in the other windings during the phase of stopping the motor in the desired position. This phase is selected by a signal (ATT) from a controlling unit (13) and the modulation is of such a sense as substantially to cancel the undesired oscillations. The circuit may be applied for example to motors for positioning typing elements in office printing or typing machines.

Abstract: The typewriter comprises a character carrying daisywheel having flexible petals which is carried by a carriage that is movable transversely with respect to the platen roller. Mounted on the carriage are a motor for moving the carriage, a motor for character selection, a print hammer, a cartridge for the typing ribbon, a correction ribbon and a drive unit for advancing the typing ribbon and raising and advancing the correction ribbon. The structure of the hammer and the arrangement of the typing ribbon and the character carrying daisywheel are such that typing and reading of the line of print are possible without it being necessary for the typing ribbon to be raised. The carriage is displaced in the two directions from the current position to an intermediate position to the left of the desired position. The carriage is then positioned precisely by a tooth-type setting means after a undirectional displacement of the displacement motor.

Abstract: The dot printer, which is of small dimensions, is used with desk top computers or as a peripheral unit with small processors. The printer writes in the serial-parallel mode by means of a thermal head (26) on a paper tape (16) wound on a writing platen (10) which advances intermittently to effect line spacing. This advancing is effected by means of a pawl (56) on a beam (50) controlled by a face cam (46) and a radial cam (48) on a cam cylinder (44) driven by a motor (45). A third cam (42) reciprocates the head (26) and, at the reversals of the head, the face cam (46) allows a spring (45) to engage the pawl (56) with a toothed wheel (62) on the platen (10) and the radial cam (48) then moves the pawl to advance the platen. The head comprises a small plate (29) of insulating material with twenty point-like resistive writing elements, and is fixed to a support (24 ) which is moved parallel to the cylinder by means of the third (42).

Abstract: One-dimensional compression is effected by addressing a first ROM (62) with information in respect of the length and the type of run. One-dimensional decompression is effected by addressing with the compressed code, a second ROM, bearing the information in respect of the runs and the length of the code. That is provided by a shift register controlled by a logic unit capable of recognising a group of least significant bits, to permit additional shifting of the register, and addressing of the second ROM with a bit number less than the maximum length of the codes. For two-dimensional compression or decompression, there is provided a pair of RAMs for temporarily storing a reference line which, together with the current line, actuates a logic means (38), for controlling coding and decoding of the latter.

Abstract: In a reproducing machine the photoconductive member, in the form of an endless belt, and the developing station are carried in a container or cartridge removably mounted on the machine. The photoconductive belt surrounds a support structure integral with the cartridge. The support structure includes a resilient portion engaging the photoconductive belt to keep it under tension around the structure. A magnetic belt of tubular form, fixed within the cartridge, is surrounded by a sleeve of non-magnetic material. The magnetic belt is so magnetized as to form a regular distribution of pairs of magnetic poles of opposite polarity. The toner adheres by magnetic action on the external surface of the sleeve to form a magnetic brush of the developing station.

Abstract: A contact keyboard comprising a plurality of modular keys individually insertable in a base frame having feet adjustable in height in order to permit a variable inclination of the key plane. The majority of the keys are of the dash actuation type, in which an actuator resiliently deforms a metallic lamina urging it from a stable configuration with opened contacts to an unstable configuration in which an electric contact is established between two parts of an electrical circuit. A group of keys is of the bistable type, in which a cam allows the actuator to stably position itself in one of two possible closed/open positions and in which the actuation is signalled by the illumination of a lamp inside the key.

Abstract: The device for positioning a video display unit (VDU) comprises a supporting structure with a spherical cap provided at the bottom of the supporting structure, and a base with a frusto-conical seat for housing the spherical cap. The center of gravity of the VDU coincides substantially with the center of the spherical cap, and the base comprises a central pin projecting into a slot in the cap. This connection of pin and slot type enables the video unit to rotate in a vertical plane passing through the slot axis and in a horizontal plane perpendicular to the pin axis. One or more spacer rings complete with seat and pin can be stacked on the base to raise the VDU.

Abstract: The device for mounting a daisy-wheel character carrying disc (70) in a printing machine comprises a frame (22) which is pivoted on a guide (13) of the carriage (12) that is parallel to the platen roller (11) and on which are mounted a selector motor (15) with which the character carrying disc is to be coupled, a striker hammer (16) and a pocket (60) into which the character carrying disc is inserted. A manually actuable mechanism (40) causes the frame (22), striker hammer (16) and the selector motor (15) to swing away from the platen roller (11) and at the same time causes the pocket (60) to be lifted, thus permitting the character carrying disc (70) to be removed and/or inserted from above. Coaxial coupling between the motor shaft (76) and the disc (70) and positioning of the disc between the platen roller and the striker hammer are effected automatically by manually actuating the mechanism (40) connected to the frame (22) to swing the frame back again towards the platen.

Abstract: The apparatus comprises an optical scanning device for scanning elements or portions of an image or for providing corresponding electrical image signals which are fed to a plurality of threshold comparator circuits where they are compared with respective reference signals which define a scale of half tones. The apparatus further includes a digital-signal generator circuit arranged to generate a plurality of digital signal combinations each of which is indicative of a respective predetermined matrix pattern of white or black points associated with a respective half tone of the scale. This generator circuit, in operation, outputs the combination of digital signals relating to the pattern associated with the half tone currently indicated by the signals provided by the threshold comparator circuits.

Abstract: An electronic typewriter comprises a character-bearing disk movable along the platen and a selector to space selected characters according to a plurality of constant spaces or proportional spaces. A permanent, alterable memory has a series of locations, wherein are recorded positioning information for the disk and the platen and constant phrases. A series of keys are operable to select associated registers of the memory to execute the movement of the disk or the printing of the recorded constant phrases, as recorded. An evidence selector is further operable at any point of the printing line to cause an evidence of printed character as bold-facing or underlining and a cancel key is provided to automatically cancel the already printed characters.The characters are carried by regularly spaced petals of the disk.

Abstract: The method enables images recorded with different definitions to be printed by the same printer, and the information to be printed with maximum print definitions. For this purpose, the print definitions (dots per mm) is a common multiple of the possible recording definitions. The information to be printed is extracted from a signal generator with a frequency corresponding to the recording definition, and is repeated in accordance with the multiple. For example with a print definition of 24 dots/mm defined by a row and column grid L1, L2, etc., C1, C2, etc., a character definition of 8 dots/mm is obtained by printing each dot three times in each row and repeating each row a further two times. The printer, which is therefor suitable for various purposes, for example as a word processor printer and as a facsimile printer, repeatedly prints each dot, along the horizontal and/or along the vertical, for a number of times corresponding to the multiple, to provide a line continuity and an improved image resolution.

Abstract: A droplet of ink 11 is expelled from a nozzle in a wall, so as to strike a printing medium, by suddenly moving the wall towards the ink 11 with which it is in contact. This movement is effected by energizing a piezoelectric sleeve. The ink droplet is expelled by virtue of the inertia of the ink resisting the movement of the wall and creating pressure. Practical embodiments are described in which the wall containing the nozzle is formed by the tapered end of a capillary tube.

Abstract: An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure, which comprises a shutter disc of transparent material, having two faces which are parallel to each other. The disc is provided with a plurality of radial shutter elements, spaced by elements which transmit the light. The shutter elements are formed by V-shaped elements provided on one face of the disc and capable of totally deflecting the light incident thereon.

Abstract: The device comprises a plurality of ink reservoirs, each connected to a number of nozzles (22) equidistant along a corresponding row. The nozzles connected to the various reservoirs are spaced apart vertically by at least one line space. The device can be used for printing different lines in parallel, moreover subdividing the length of the line, or for printing different zones of the sheet in facsimile. The ink is kept in circulation between the reservoirs and the nozzles by a common peristaltic pump which acts by a series of actuating elements on the discharge ducts for the inks in the reservoirs. The reservoirs may contain inks of different colors to permit printing in different colors or polychrome facsimile printing by additive or subtractive synthesis of the colors. The ink is conductive and is kept at earth potential, while electrodes (23) disposed outside the corresponding nozzles (22) are energized selectively to produce sprays of particles of ink from the nozzles.