Abstract: A line spacing device for printing machines comprises an electric motor arranged to rotate selectively in a clockwise direction and anticlockwise direction and a control disc carrying a pawl on an eccentric. The tooth of the pawl describes a closed trajectory engaging in the teeth of a wheel and of a sense the same as the rotation of the disc, whereby a paper support platen is rotated by one increment in the opposite sense. A central control unit controls the clockwise and anticlockwise rotations of the electric motor. A cam disengages a detent pin from the wheel so that the motor is only lightly loaded when actuating the platen.

Abstract: An erasing ribbon is guided by the same vibrator as the typing ribbon behind the lower part of the typing ribbon. An erasing key acts on the back-spacing mechanism of the typewriter and on an element which suppresses the carriage escapement during a correction cycle initiated by any one of the typing keys. The necessary settings are made by a slide which stores the erasing key command. In particular, the slide acts on a lever which varies the stroke of the ribbon vibrator for selecting the erasing ribbon, also on a device which causes the erasing ribbon to advance and on a mechanism which inhibits the escapement during the execution of the correction cycle. The setting slide is then returned to rest by the first typing key operated after the erasing cycle. A correction selection lever acts on the lever which varies the stroke of the ribbon vibrator and selects permanently the erasing ribbon independently of the erasing key for a forward erasing of the characters of one or more words.

Abstract: An ink-jet printer includes a reservoir filled with ink and an ink duct communicating with the reservoir. The duct has a terminal portion with a capillary nozzle for projecting the ink, and an intermediate portion between the reservoir and the terminal portion. Transducer means are associated with the terminal portion of the duct for generating a first pressure wave in the ink, which is directed towards the nozzle and causes a droplet of ink to be discharged through the nozzle. Energy absorption means cooperate with the ink in the intermediate portion of the duct and comprise an elongate container adjacent at least part of the intermediate portion of the duct and having at least one wall which is in contact with the ink and can deform resiliently under the action of a second pressure wave associated with the first pressure wave and directed towards the intermediate portion of the duct.

Abstract: An ink-jet printer includes a reservoir filled with ink and a duct communicating with the reservoir and also filled with ink. The duct has an end portion with a capillary nozzle for projecting the ink and an intermediate portion between the reservoir and the end portion. Transducer means are associated with the end portion of the duct for generating a first pressure wave in the ink, which is directed towards the nozzle and causes a droplet of ink to be discharged through the nozzle. A second pressure wave associated with the first pressure wave is directed towards the intermediate portion of the duct and, to substantially absorb the energy of this second wave, the printer further includes an elongate damper which extends in contact with the ink in only the intermediate portion of the duct.

Abstract: The varnish comprises a plasticizing resin, a diluent, a matting compound and an epoxy silane compound, this latter having excellent antireflection characteristics and enabling the varnish also to adhere to smooth glass. At the moment of use, a catalyst is added to the varish, the catalyst being an amino silane compound which causes the epoxy compound to polymerize, so that the varnish layer becomes resistant to abrasion and to chemical agents. The varnish can also be colored with aniline dyes such as aniline green and aniline yellow. On varnishing, the tube is first degreased, then varnished with several layers, and finally baked at a temperature of between 80.degree. and 150.degree. C. for a time sufficient to cause polymerization of the compound.

Abstract: A display device 10 consisting of five cells of seven segments each, is used in a photocopying machine in order to indicate normal operation and certain abnormal situations. The latter are indicated by means of messages in plain language, represented by cyclically moving characters. The messages are stored permanently in an EPROM 50, from which they are extracted as required under the command of a CPU 80 in relation to the corresponding type of abnormality, as detected by a set of sensors 82, 84, 86. A suitable subroutine causes the letters of message to slide along the cells of the display device 10 from right to left.

Abstract: A screen (30) is suitable for screening the electronic circuits (20) of an office machine with a plastic base (13) and hinged cover (14). The screen (30) comprises a thin, flexible insulating layer metallized on its underside and is disposed below the circuits (20). Screening above is provided by the metal mechanical parts (18) which make electrical contact with the metallized layer by pressing onto tabs (35,36) of the screen, bent over resilient pads.

Abstract: Positioning device for a printer comprising a type carrier daisy wheel fitted on a carriage movable in front of the platen. The selection of type and movement of carriage are carried out by selection and transport motors of direct current type which are controlled by velocity servo motors through corresponding digital transducer and position counters. After a coarse positioning by the servo motor, the exact final position is reached and kept by exciting a couple of magnetic positioners whose rotor is keyed on the axes of the selection and transport motors.Economic solutions are also described to synchronize, during initialization of the machine, the content of the position counters with the effective positions of the daisy wheel and carriage.

Abstract: The head is provided for a conducting ink and comprises a closed container (14) carrying two electrodes and a nozzle (18). The head is removably mounted on a carriage (13) and is replaced when the ink is exhausted.The container (14) is divided into two cavities (71 and 72) which are in communication by way of an aperture (73, 74, 75) in order to cause ink to flow to the nozzle and to remove bubbles. To ensure that the bubbles do not cause an increase in the pressure in the container, causing the ink to discharge from the nozzle, the container comprises an expansible cavity formed by a bag-type diaphragm (83) and a compression spring (82) which tends to cause expansion of the cavity.The container is filled with ink, while holding the spring in a compressed condition. As the ink decreases, the spring expands, maintaining a slight depression within the container.

Abstract: The printing head (12) comprises an insulating container (14) for conductive ink (16) which is expelled through a fine nozzle (18) when a voltage pulse is applied between an electrode (56, 57, 40) and a counter-electrode (22). Capillary passages (51, 50) lead to the nozzle (18) to allow formation of an ink meniscus (23) right up until exhaustion of the ink. A vent (69) keeps the pressure inside the container constant. The head (12) is snap fitted onto a carriage with a conductive plate abutted by the counter-electrode (20) and a spring contacting the external part (40) of the electrode. This plate and spring are fed by way of conductive elements sliding along conductive carriage guides.

Abstract: The device comprises a printing head (15) constituted by an insulating container (19) with a capillary nozzle (36). The electrically conductive ink is kept under circulation in the container via a feed tube (26, 23) and a return tube (27, 24) leading to a suction pump, in order to allow the formation of a convex meniscus at the exit aperture of the nozzle (36) and eliminate any vapor bubbles. A pulse generator creates a voltage of a predetermined value and duration between an electrode (37) external to the nozzle and an electrode (23) in contact with the ink, in order to create a state of excitation of the meniscus and partial vaporization of a layer of ink, such as to expel a plurality of ink particles. The head is mounted on a carriage movable transversely to the paper, which advances at each stroke reversal of the head.

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. The electronic unit provides a line buffer on which the entered characters of a line are sequentially stored and a series of editing functions to have the entered characters directly printed in editing form and a permanent, alterable memory wherein are recorded positioning information for the disk and constant phrases to be printed can be recorded and recalled upon request of the operator. Justification of a line is commanded by a selector which allows the printing of entered characters up to a set zone of the printing line while stores, without printing, the remaining characters on the line buffer. Following actuation of a service key causes the delayed printing of stored part of the line aligned to the fixed right margin.

Abstract: The printing and correcting device is applied to a daisywheel printer and comprises a frame supporting a cartridge for a typing ribbon and a correcting ribbon arranged below the typing ribbon. The frame is able to swing as the result of operation of an electromagnet, from a rest position providing visibility of the print, to an intermediate position for printing the characters. A second electromagnet raises the frame through a greater length of travel in order to position the correcting ribbon in front of the printing point. A rotating electromagnet causes automatic unidirectional advance of the typing ribbon after each character has been printed. The correcting ribbon is wound between two spools and its motion is provided by means of a pawl which engages with a gear wheel for driving the spool only in the case where the path of travel of the frame is greater than that which relates to positioning of the typing ribbon.

Abstract: The keyboard of an electronic typewriter with a daisywheel print unit on a carriage includes a CENTER key and REPEAT key. With the print unit positioned where an insertion is to be made in a line being set up blind, these keys are actuated and the character to be inserted are typed in. The usable area for typing is continually shown on a two-digit display device. When a service key is then depressed, the line is printed with the inserted character entered by appropriate compression or expansion of empty spaces adjacent the characters to be inserted. The typewriter further comprises a line space memory and a control circuit which signals the number of line spacing commands which can still be carried into effect before the last line to be typed on the sheet.

Abstract: The control system is applied to an ink jet head in which the individual drops of ink are expelled from a container by way of a nozzle by the effect of contractions of a piezoelectric transducer applied to the container. The transducer is included in an oscillatory circuit which is normally connected to a dc voltage source. A pulse generator acts on a switch to generate a voltage wave in the oscillatory circuit of the transducer and interrupts the pulse when the current in the oscillatory circuit goes to zero, whereby a single voltage wave with a low harmonics content is generated. The oscillatory circuit is so designed that the frequency spectrum created by the voltage wave drops rapidly with frequencies higher than the resonance frequency of the oscillatory circuit and has at least one node close to the resonance frequency at the lowest nodal diameter mode of vibration of the meniscus.

Abstract: An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure comprises a disc 13 mounted rotatably within a casing. The disc is provided with a plurality of opaque radial regions 19 which are spaced by transparent regions 18 which transmit the light emitted by a light source mounted on the casing. The light is received by a photodetector element 25 comprising a support plate 28 on which is disposed a multiplicity of photovoltaic cells 26 each having an area which is fraction of the area of each transparent region of the disc. The cells are subdivided into the groups A, B and C with different functions and phase positions and are distributed diffusely over the area encountered by the beam of light from the light source. The cells of each group are connected together in parallel to generate three electrical signals, one of which provides pilot control for the feed to the light source to stabilize the signals of the other two groups of photoelectric cells.

Abstract: A first carriage carries a lamp for illuminating the original and a first mirror. A second carriage carries two mirrors and moves at half the speed of the carriage so that a constant optical path length is maintained from the original, via the three mirrors and a focusing lens to a rotating image receptor drum. The carriages are driven by individual motors via pulleys and belts and, during scanning, the speeds of the two motors are controlled in sympathy to move the carriage at a speed corresponding to the selected reduction/enlargement factor and to move the carriage at half this speed. Before scanning, only the second motor is energized to position the second carriage in accordance with the said factor. In a modified embodiment, a clutch couples the two carriages for movement at the correct relative speeds during scanning which is effected solely by means of the first motor. The initial positioning of the carriage by the second motor is effected with the clutch disengaged.

Abstract: A cash register with a keyboard (31), journal printer (47) and a check slip printer (32) is controlled by a microprocessor system with a CPU (102), a program ROM (105) and a RAM (106) including various registers for storing running totals of various types. The printer (32) prints till receipts and end-of-day check slips authenticating non-rigged operation of the cash register. Thus, each time such a check slip is printed a fresh bit of an EPROM memory (106) is set from 1 to 0 under control of a register (181) and a pulser circuit (191), the EPROM being fixed non-removably to the machine and shielded aginst UV erasure. The printed check slip includes the serial number thereof as represented by the EPROM contents, a special symbol identifying a non-manipulatable machine and the machine number recorded in a section (161) of the EPROM. In a modified embodiment the EPROM is replaced by a counter, e.g. a mechanical counter, which can only be incremented (and cannot be decremented or zeroized).

Abstract: Device for automatically positioning a sheet on an office machine platen, including a lower guide element to guide the sheet toward the writing line of the platen and an upper guide element to guide the sheet towards the top. During the introduction of the sheet, an electromagnet is energized to let the lower guide element turn with the platen, accompanying the sheet beyond the writing line. The electromagnet also causes the contemporary separation of the upper guide element from the platen. When the sheet reaches a predetermined position with respect to the writing line, the electromagnet is de-energized and a spring again brings the two elements to the rest position. An automatic introduction mechanism sequentially transfers the sheets from a hopper to the platen and from the platen to a sheet stacker.