Abstract: A cassette for a printing ribbon comprises a casing accommodating a supply spool which has a tube on which the printing ribbon is wound. An anti-unrolling element of plastics material comprises two portions of elongate shape, which are connected by means of an integral elastic hinge. The first portion performs a guiding and positioning function and is accommodated by means of a slot within the casing. The second portion has a blocking function with regard to the tube, and is movable on the outside of the casing, by means of the elastic hinge, from an inoperative position in which it is aligned with the first portion to an operative position in which it is rotated through 180.degree. and is substantially in superposed relationship with the first portion.

Abstract: A cartridge for a correction ribbon for typewriters comprises a container for a supply reel and a receiving reel. A tensioning device comprises a toothed ring on the supply rell and a spring which is pivoted in the container and which has one end engaged with the toothed ring to tension the ribbon. The container can be removably fixed to the lower part of a cartridge for a typing ribbon which in turn can be fitted on a support of the machine. The support is movable from a viewing position to a typing position in which the typing ribbon is in front of the point of typing and to a correction position in which the correction ribbon is in front of the point of typing. The receiving reel of the cartridge, in use, is capable of co-operating with a feed mechanism which provides for forward feed movement of the ribbon in each correction cycle.

Abstract: The original documents of A4 or A3 format are selectively read by a scanning apparatus which is integrated into a system for producing and transmitting images. The originals of A4 format are normally positioned on a fixed exposure surface and the originals of A3 format are introduced into a separate device for transporting documents, which is adjacent to the fixed exposure surface. A carriage with lamps is slidable below the exposure surface to illuminate the A4 original while to illuminate the A3 original the carriage is positioned into a fixed position corresponding to the separate reading device where the original A3 is slid with respect to the carriage past an exposure zone. The reflected images of the originals are passed by means of mirrors mounted on the carriage to a lens which reflects them on to a photodetector device which converts the light rays into digital electrical signals.

Abstract: Each needle of the printer has an associated electromagnet with a generally elongate movable armature having a first end and a second end which can selectively push the needle during printing as a result of a pivoting movement within a step formation facing the electromagnet. The step formation divides the armature into first and second portions facing the first and second ends respectively, and faces the respective electromagnet in such a position that the second portion of the armature at least partially faces the electromagnet.

Abstract: A cartridge for a typewriter typing ribbon comprises a container for accommodating the typing ribbon which can be of correctable or non-correctable type. A corrector cartridge can be removably fixed on the lower part of the container by engagement means. The corrector cartridge accommodates a correction ribbon which can be of the lift-off type suitable for the typing ribbon of correctable type, or of the cover-up correction type which is suitable for the typing ribbon of non-correctable type. Coupling means on the cartridge and the corrector cartridge permit the engagement means removably to fix the corrector cartridge to the container only when the caartridge houses the typing ribbon of correctable type and the corrector cartridge houses the correction ribbon of lift-off type or alternatively when the typing ribbon is of non-correctable type and the correction ribbon is of the cover-up type.

Abstract: The background compensation circuit defines a background threshold signal in dependence on an average value between the positive-peak and negative-peak signals previously received from the elements for scanning the pixels of the image, and in dependence on the analog signal (AS) of the pixel added to a reference signal. The circuit comprises two detectors (21, 22) for respectively detecting a positive peak and a negative peak and which each have a short charge time constant and a long discharge time constant. A summing circuit (25) generates a threshold signal (V.sub.s) as a linear combination of the signals (V.sub.max, V.sub.min) of the detectors (21, 22) the analog signal (AS) of the pixel and a reference signal (V.sub.r). Finally the threshold signal is compared (26) to the analog signal (AS) of the pixel to produce a binary reading signal which is at "one" level when the threshold signal is greater than the analog signal and is at "zero" level when the threshold signal is less than the analog signal.

Abstract: The apparatus for reading and digital processing of color images comprises groups of CCD sensing elements for reading the individual pixels forming the image. Each group of the sensing elements is associated with one primary color, for generating corresponding reading signals, which control a color indication circuit generating a color indicatory signal for indicating the presence of any color in the image. The colour indicator signal is derived from a table of zones of colours which is recorded in a ROM and can be addressed by the reading signals of the various colours, input from corresponding reading elements via compensation circuits. The colour signal is capable of controlling second selective scanning of document for recording the reading signals for all the primary colours of the image. The ROM is also capable of providing an indication of the mixture of colours of each pixel, which is compared to a predetermined mask for the purposes of suppressing a particular mixture of colours from the recording.