Abstract: A ribbon cartridge for use with a printer is disclosed having a removable capstan. The removable capstan may be interchanged with other capstans having different circumferences and configurations for engaging printer drive mechanisms of different printers. Both single pass and invertible cartridges may use the removable capstan of the present invention. In an invertible cartridge application, only one capstan is required to advance the ribbon in either direction.

Abstract: A cartridge is provided with an improved drive which meters ribbon to a constant and selected rate of ribbon advance. At least one ribbon drive cylinder is provided around which the ribbon is wrapped. The drive cylinder is preferably a rubber cylinder of selected diameter constituting a force fitted sleeve on a metering gear. Provision is made for a single but reversible coaxial small and large gear pair to mount at two different locations in the cartridge between a driven gear and the metering gear. The coaxial gears include a first large diameter gear with a greater number of teeth and a smaller diameter gear with a lesser number of teeth. By assembling the large gear in mesh the drive gear and the small gear in mesh with metering cylinder gear, ribbon speed is reduced. The ribbon can be moved at a low speed such as required in multi-strike ribbon applications.

Abstract: The cartridge comprises two arms situated on both sides of the cartridge y; each arm can occupy either a first, non-functional position (or storage position of the cartridge) or a second, functional position (or use position of the cartridge). Elastic tension means are provided to act on the ribbon to hold the latter taut whatever the functional or non-functional position occupied by the arms.

Abstract: An apparatus for use with a cassette having accommodated therein an ink material, a feed roller and a take-up roller for the material. A pair of driving heads in the cassette loading portion of the apparatus are automatically connectable to or disconnectable from the opposite ends of the take-up roll by spring levers which are movable in response to the loading or unloading of the cassette. When connected to the take-up roll, the heads center the take-up roll and position the roll in place axially thereof. The feed roll is positioned in place by V-shaped bearings in the loading portion. Thus, the two rolls can be positioned accurately automatically without necessitating any special procedure.

Abstract: A multifunctional cassette (1) for a printer (131), in which the cassette (1) that can be arranged in the printer (131) is provided with first, second and third chambers (31, 35, 37). The second chamber (35) and the first chamber (31) can accommodate a supply reel (59) and a takeup reel (57), respectively, for transport of a color transfer strip (55) past the printing head (143), while the third chamber (37) can comprise a supply of a data strip (41) to be transported along the printing head (143). Pins (103, 105) brake the web when the cassette is not in the printer. Whether using or not using the first and second chambers (31, 35), the multifunctional use of the cassette (1) becomes possible for different types of printers, such as black-and-white printers and color printers.

Abstract: A ribbon stabilizer or guide member is provided in a ribbon reversing section of a ribbon cassette to prevent adverse twisting of the ribbon and to correct irregular twisting thereof and to maintain the normal reverse action or operation of the ribbon in its travel through the cassette.

Abstract: An electrothermal printer having a print head provided with a plurality of wire electrodes, an ink ribbon, and a heating ribbon separate from the ink ribbon. The heating ribbon is in the form of a layer of material which is a poor conductor of electricity and a layer of electrically conductive material. The current passing between one or several of the electrodes in the print head to the heating ribbon conductive layer which is in contact with an appropriate sliding contact or electrode heats a localized area, or localized areas, of the heating ribbon which in turn transfers heat to corresponding localized areas of the ink ribbon for transferring ink on a sheet of paper. The ink ribbon and the heating ribbon are displaced at the same speed past the print head. The printer of the invention permits high rate printing at a relatively low cost of supplies. With the ink ribbon omitted, printing can be effected directly on thermo-sensitive paper.

Abstract: A dog clutch is disclosed for interconnecting the drive mechanism of a cartridge holder and the ribbon drive in a cartridge, which clutch permits a coupling in any position of the coupling parts. One coupling component is a hollow pin in the opening of which the spindle with knife-like entrainment componets can be inserted for rotary entrainment under elastic deformation of the wall of the hollow pin.

Abstract: In a replaceable ribbon cartridge (12) for printers in which the ribbon (14) can be guided out of the cartridge through an exit opening (16) and at the end of a tension segment extending outside the cartridge can be reintroduced into the cartridge through an entrance opening (18), there is arranged on the cartridge (12) in the zone of the tension segment at least one deflection slide (24, 26) displaceable in a direction approximately perpendicular to the ribbon plane between a position of retraction into the cartridge (12) and an extended position deflecting the ribbon (14). Through the deflection slide or slides (24, 26), the ribbon (14) is generally spread away from the cartridge sufficiently so that upon insertion of the cartridge into the printer, it places itself around the printer head.

Abstract: A shell-type printing apparatus is equipped with a link mechanism for loading and unloading an inksheet cassette from the printing apparatus. The link mechanism comprises a support frame which supports an inksheet cassette and two pairs of links which have one end pivotably mounted on the base of the printing apparatus and the other end pivotably connected to the support frame. The link mechanism rotates the support frame between a first and a second position. In the first position, the support frame is disposed above and to the front of the base of the printing apparatus so that an inksheet cassette can be mounted on the support frame. In the second position, the support frame is disposed inside the base and the inksheet cassette is disposed in the proper position for printing.

Abstract: A thermal transfer printer wherein a ribbon cassette adapted to receive therein an ink ribbon which is guided outside from a ribbon take-out portion in a manner such that the ribbon is drawn out of a ribbon pull-in portion is placed on a carriage, and a head mounting member supporting the thermal head is disposed within a recess formed on the platen side of the carriage so that the mounting member may be moved to and from the platen, characterized by the provision of a moving mechanism in which the width of the recess in the carriage moving direction is formed to be larger than that of the head mounting member in the same direction as the former so that the carriage and the head mounting member may be relatively moved in the carriage moving direction, and the head mounting member and the carriage may be relatively moved so that when the head mounting member is projected from the recess of the carriage toward the platen, the head mounting member is moved close to the ribbon pull-in portion of the ribbon casset

Abstract: An automatic cut-sheet feeder incorporated in a printer includes an upper sheet guide having an ink ribbon replacement recess defining a clearance between the upper sheet guide and a print head of the printer for thereby allowing an ink ribbon cassette to be replaced with ease. When a cut sheet is fed to the front side of a platen, the print head mounted on a carriage is controlled to move to a position corresponding to the ink ribbon replacement recess in the upper sheet guide. The printed cut sheet can smoothly be discharged by the upper sheet guide into a stacker. The ink ribbon cassette on the print head can easily be replaced with a new one.

Abstract: A ribbon cassette is provided with a rotatably mounted ribbon supply spool whose flange has markings, angularly spaced according to ribbon type, which are adapted to be successively sensed as ribbon is incrementally drawn off a supply spool to provide signals from which the type of ribbon in the cassette can be identified and the feed increments therefore determined, and information regarding the supply of ribbon remaining on the spool, end of ribbon and ribbon jams may be derived in a programmed control unit. The ribbon cassette further comprises a two-armed lever pivotally mounted in the cassette housing, having first and second lever arms which engage teeth on the edge of the spool flange when the two-armed lever is in a first end condition and a second end condition respectively.

Abstract: A re-inking device is fitted to a cartridge for an inked ribbon. The cartridge comprises a magazine housing the ribbon which is of the closed loop type and which is disposed in randomly distributed loops, and a pair of rollers for the unidirectional feed movement of the ribbon. The re-inking device comprises an ink reservoir or inker, an ink metering wick and a spring. The pair of rollers comprises two toothed wheels and the inker is disposed in a housing adjacent to the wheels. The ink metering wick comprises a bundle of capillary fibres and is disposed between the inker and the wheel. The spring presses on the metering wick to hold the fibres at one end in constant contact with the outside surface of the wheel. The crests of the teeth of the wheels are of a rounded section and the inker is of a parallelepipedic shape, is of polyester fibres with external co-extrusion and contains an amount of ink such as to occupy only half the volume of the inker.

Abstract: An ink ribbon cartridge for use in a typewriter, printer and the like includes a driving mechanism to move a strip of ink ribbon out of the cartridge through a supply port and again into the cartridge through a take-up port and a deterrent mechanism to impart a back tension to the ink ribbon when pulled toward the take-up port from the supply port. The deterrent mechanism includes a guide post and a leaf spring whose forward end is pressed against the guide post with the ink ribbon sandwiched therebetween. The forward end of the leaf spring is provided with oppositely extending side projections which are inserted into the relief holes provided in the top and bottom walls of the cartridge. More preferably, the guide post extends from the bottom wall and extends into the relief hole of the top wall.

Abstract: Grounding members are provided on support plates for an ink ribbon cassette, the support plates are secured to a chassis. The support plates and the chassis are both made of electrically conductive material. When an ink ribbon cassette is placed on the support plates, the grounding members contact the ink ribbon to ground static electricity.

Abstract: An ink ribbon cassette having a multicarbon ribbon for switching from a rapid to a slow multicarbon mode is provided. The cassette includes a coupling element to be driven by a printing device. The coupling element rotates a manually shiftable gear mechanism which includes two sets of gears, which are axially displaceable with respect to each other. Each set of gears includes gears of different sizes with a driving wheel mounted on one set of gears. The driving wheel engages the ink ribbon take-up reel. The ability to change the speed of the ribbon advance makes it possible to use the same multicarbon ink ribbon cassette either for high print quality or for longer print duration.

Abstract: A color ink ribbon in which one half of the width of the ribbon is utilized for the left-to-right (first) printing direction and the other half of the width is utilized for the right-to-left (second) printing direction, and in which the sequence of ink layers composed of at least three colors is the same for both printing directions, whereby the ribbon can be used for printing in both the forward and reverse directions without wasteful non-utilization of areas in either half of the ribbon.

Abstract: A printer of heat-sensitive transfer type has a horizontally arranged ink ribbon cassette to print a sheet of printing paper with the ink ribbon. The printer comprises: a platen for holding thereon the printing paper; a horizontal printing head made movable along the platen for bringing the ink ribbon into close contact with the printing paper held on the platen to thermally transfer the ink of the ink ribbon onto the printing paper; and a carriage made movable longitudinally of the platen, while carrying the printing head thereon, in accordance with the printing operation of the printing head. An ink ribbon peeling member is arranged horizontally on the sides of the printing head and carried together with the printing head by the carriage for sequentially peeling off that portion of the ink ribbon, which has been used for the printing operation, from the printing paper.

Abstract: A ribbon cartridge comprises a case, a sliding guide slidably mounted in the case, and an endless ink ribbon enclosed in the case. A greater part of the ribbon is enclosed in the case at a space between the sliding guide and an inlet side of the case. The sliding guide has a front guide plate at an inlet side thereof, and a rear guide plate at an outlet side. The front guide plate has a vertical inlet slit and the rear guide plate has an inclined outlet slit. The ink ribbon is engaged with both the slits so as to correct any twist thereof.

Abstract: An improved drive mechanism for an ink ribbon cassette for advancing an ink ribbon particularly well suited for use in a typewriter is provided. The drive mechanism includes a drive roller rotatably supported in the casing with a free floating pressure ring supported by a roller. The pressure ring is supported against the roller and against the drive roller so that there is an increase in pressure with an increase in the tension of the ribbon.

Abstract: An ink ribbon cassette includes a case, supply side core rotatably held by the case and having an uneven portion in a portion thereof, an ink ribbon wound on the core, a take-up side core rotatably held by the case to take up the ink ribbon, and a spring resiliently engaged with the uneven portion of the supply side core and resiliently pressing the outer periphery of the ink ribbon wound on the supply side core.

Abstract: Typing ribbon cartridge for typewriting and/or printing machines in which a typing ribbon (2) has a section that runs freely outside the cartridge housing between two housing side-arms (4). To select one of several typing tracks this section is moved perpendicularly to the longitudinal axis of the ribbon section in such a way that equalization of the differing tensions of the ribbon edges in the various positions of the free section of the ribbon is obtained. For this purpose guide elements (9) are provided, which are mounted on guide edges of the side-arms (4), which are arranged perpendicular to the longitudinal axis throughout their entire length and in the ribbon plane, and the guide elements are tiltable about axes (15), which are arranged perpendicular to the plane of the free section of the ribbon and which intersect the guide edges.

Abstract: A ribbon cartridge for printing apparatus is provided selectively with a color selection mechanism, when the cartridge is loaded with a multi-color ribbon, operated by moving the printer-carriage to a position beyond the print line limit and with a peg arranged to engage a cam mechanism on the print carriage, when the cartridge is loaded with a single color ribbon, to enable the full width of the ribbon to be utilized. The peg is formed integrally with the cartridge and is removed when a multi color ribbon is to be loaded in the cartridge.

Abstract: A ribbon lifting mechanism usable for a typewriter including a holder turnably supported in a frame, a motor driven ribbon lifting cam and at least a cam follower operatively connected to the holder. Printing ribbon and correction tape are accommodated in the holder and either of them is located at the printing position by means of the ribbon lifting cam which is formed with a plurality of cam sections. The cam follower is actuated in accordance with cam sections on the ribbon lifting cam. The mechanism further includes a stopper member which serves to locate the printing ribbon at the printing position while it is engaged to the holder. The stopper member also serves to locate the correction tape at the printing position while it is disengaged from the holder.

Abstract: A ribbon cartridge having a pair of movable arms extending outwardly from the body, over which the ribbon passes on its transit from an internal ribbon supply to an internal used ribbon storage. Each of the arms is supported for movement about an oblique axis which moves the active marking portion of the ribbon so that the path traversed by one edge is equal in length to the path traversed by the opposite edge.

Abstract: Ribbon cartridges for typewriters or similar office machines must meet various design requirements, especially, must be easily exchangeable without soiling one's fingers, must be inexpensive to manufacture, and must dampen the noise in the printing area. To be avoided in addition is a soiling of the machine components when using the cartridge, through ribbon rub-off dropping through the holes in the bottom of the cartridge, and a smooth ribbon drive must be possible. These various problems are inventionally solved in that the cup-shaped base component of the cartridge casing features on the inside of the bottom protruding stiffening ribs which likewise serve to support the spools of the flangeless supply and take-up reels and/or prevent ribbon rub-off accruing in the cartridge casing from dropping out of the openings.

Abstract: A print ribbon cassette includes a supply roll and a take-up roll so that the print ribbon unwound from the supply roll is presented for use in printing and thereafter wound around the take-up roll. The cassette also includs an endless belt extended around a driving roller and a pair of belt rollers. The driving roller is provided fixed in position and coupled to a driving motor of a printer when the cassette is mounted on the printer. On the other hand, the belt rollers are rotatably mounted on separate support arms which are pivotally mounted on the cassette. When the support arms are located at an operative position as extending substantially in a line and opposite in direction, the belt is brought into driving engagement with both of the supply and take-up rollers.

Abstract: A printer characterized in that a paper feed path for guiding a record paper to a printing position formed between a platen and a head is disposed on the same plane on the whole including the printing position and portions before and behind the printing position.

Abstract: A printing apparatus having a carrier which reciprocates along a print line defined on a platen, comprising a first printing assembly supported on the carrier and having type elements abuttable on the platen for printing characters, and a second printing assembly supported on the carrier for printing characters by a dot matrix. The first and second printing assemblies have a first and second print point, respectively, which are spaced from each other in a direction parallel or perpendicular to the print line. Each print assembly has its own ribbon cassette; one is parallel to the print line and one is perpendicular to the print line.

Abstract: When a ribbon cassette containing a print ribbon and having a looped portion exposed to the outside is mounted on a printer frame, a ribbon guide member movable along a print line of a platen, while in its initial position, is located within a region surrounded by the looped ribbon portion. The ribbon guide member is moved as a carriage mounted with a print head travels. While in engagement with the looped ribbon portion, the ribbon guide member moves to a position beyond one end of a printing range, where it is releasably latched. Thus, the ribbon is automatically stretched to cover the whole printing range.

Abstract: A ribbon cassette for typewriters is provided with an end-of-ribbon signaling device which takes the form of a switch comprising a contact web on a ribbon tensioning lever associated with the supply spool in the ribbon cassette and two contact pins provided in the machine. The contact web is adapted to bridge the contact pins signaling end of ribbon when the ribbon supply is used up.

Abstract: A printer for performing recording successively while a recording head moves backwards and forwards in a predetermined direction with respect to a recording medium such as paper. A paper hold roller for pressing the recording medium against a platen in the vicinity of a recording area opposite to a print head is detachable from the platen in relation to the movement of a carriage for carrying the recording head. The presence and absence of paper is detected to control the paper feed. An ink ribbon is provided which has color zones and an ink absorption zone in the direction of the ribbon width for multi-color printing by shifting the ribbon in the width direction by means of the carriage movement so that a selected color zone faces the recording head. The printer further includes a ribbon cassette, means for controlling paper insertion and feeding and means for cleaning the recording head. Also included are a paper bail control, color zone selector and paper detector.

Abstract: A movement monitoring device for monitoring the movement of items past or through a work station wherein the items move synchronously with a ribbon through or past the work station. The transport of the items is monitored by a detector which monitors the linear movement of the ribbon. Signals from the detector can be used to activate the work station at intervals corresponding to the passage of the items.

Abstract: An improved image building apparatus of the type including a platen roller and a recording head in which a recuired image is built on printing medium by transfering coloring agent on ink donor medium onto printing medium with the aid of the recording head which is activated in response to image information while ink donor medium and printing medium are interposed between the platen roller and the recording head. To construct the apparatus in smaller dimensions the platen roller is disposed in the area located between a pair of cores in the cassette in which ink donor medium is spanned therebetween. Arrangement is made such that the platen roller is displaced together with the cassette as the latter is fitted to or removed from the housing of the apparatus. The housing includes a pair of casette supporting members which are removably inserted into openings of the cores in the cassette.

Abstract: A ribbon shifting device has a cassette holder for holding a multicolor ribbon cassette, which is moved in a predetermined direction by a cam. The cam is driven by a driving means through a gear train consisting of at least two gears. When the cassette holder is located at the home position, a recess formed in one of the meshing gear is brought opposite to the other gear, so that the gears are disengaged, and then an urging means urges the cam in a direction to bring the gears into engagement. Thus, the adjustment of the home position of the cassette holder is achieved simultaneously, accurately and easily.

Abstract: A lettering apparatus adapted for receiving a replaceable tape supply cartridge comprising a pair of spaced apart, parallel frame members defining a cartridge receiving cavity and a print bar pivotally supported between the frame members. The apparatus also includes an improved force resisting arm.

Abstract: A thermal transfer recording system comprising a supply cartridge including a case and an image forming sheet and an ink sheet housed in the case, taking-out means for taking out the image forming sheet and the ink sheet from the supply cartridge and print means including a thermal head for printing on the taken-out image forming sheet by the taken-out ink sheet.

Abstract: A printer (1) having a guide (13,15,16) for an insertable cassette (17), which is provided with a data strip (175) displaceable along a printing head (19). In certain arrangements the cassette may also include a transfer strip (177), which could include colored portions. The cassette (17) has an entrance window (167) for a transport roller (65) pivotable in the printer (1) by translation of the cassette (17). During printing, the data strip (175) and the transfer strip (177), if any, are clamped between the printing head (19) on a first cassette side and the transport roller (65) pivoted from a second cassette side located opposite the first cassette side into the entrance window (167). Separate gear wheel trains both driven by the same motor transport the two strips when both are provided.

Abstract: A single pass ink ribbon cassette for typewriters or like machines is designed to track ribbon extending between a supply and take-up spool in such a manner that text contained on used ribbon beyond a point of impression is rendered illegible. Used ribbon is rendered illegible in that upon its entry into the cassette, it is guided around a turn around roller for passage past the point of impression a second time before re-entry again into the cassette, and conducted via guide means for take-up by a driven take-up spool. Due to the fact that the ink ribbon is guided past the point of impression a second time, subsequent impressions on the used ribbon render the text from the used ribbon unreadable. In addition, in the zone of the turn around roller a scraper is provided for scraping the residual ink particles off the used ribbon before it is guided past the point of impression the second time.

Abstract: An improved transfer material holding cassette is provided with a rotation inhibiting means which serves to inhibit the core from being rotated freely at a time before it is fitted to the housing of an image building apparatus in which an image is built using the transfer material and release it from the rotation inhibited state when it is fitted to the housing. The rotation inhibiting means is located opposite to the plane of a core extending at a right angle relative to the axis of rotation of the core and comprises a lever turnably supported on the inner wall of the case to turn about the middle part thereof, the one end of the lever being located opposite to the plane of the core and the other end of the same being located opposite to an opening on the case, and a resilient member adapted to normally turn the lever in such a direction that the one end of the lever comes in contact with the core under the effect of a resilient force so as to inhibit the core from being rotated freely.

Abstract: An ink ribbon cassette is constructed such that it is unnecessary to wind off an ink ribbon at the start of every line printing process. The cassette includes two pairs of reels, each pair including an ink ribbon-winding off reel and an ink ribbon-winding up reel. The pairs of rails are rotatably mounted one above the other on a cassette casing which is detachably mounted on a carriage of a printer. The casing is provided with a driving shaft which is rotated in normal and reverse directions in response to reciprocal movement of the carriage. The driving shaft being provided with two one-way clutches transmitting the rotation of the shaft in opposite directions. Conveying members separately convey the ink ribbons for the respective pairs of reels and are driven by respective to the one-way clutches.

Abstract: A printer ribbon cartridge of the type employing two ribbon spools. In this one, the ribbon is driven by a belt engaging the spools and, in turn, the belt is engaged by both of two alternately driven drive rollers. The ribbon departure or arrival of a ribbon from or to a spool occurs on a side of a spool opposite to that of engagement of the belt with a spool.

Abstract: In a paper feeding and ejecting device for a printing apparatus, a sheet of paper is fed by a paper feeding roller from the top of a stack of paper sheets in a magazine through a feeding guide to a gripping assembly on the peripheral surface of a platen which is rotated in one direction during printing and in the opposite direction during ejecting of a printed sheet through an ejecting guide to ejecting rollers. The feeding roller and the ejecting rollers are driven by a single reversible drive motor at suitable times during the operating cycle. The feeding guide and the ejecting guide are separated from each other at the platen so that the feeding of a sheet to the platen will not interfere with the ejecting of a printed sheet. At the completion of each operating cycle, the feeding roller is accurately located at a standby position without requiring the use of a control sensor therefor.

Abstract: In a machine which uses cassettes, a compartment is provided for receiving the cassette. Examples of such machines are printing machines using an inked ribbon cassette. In the compartment there is a V-shaped toggle spring which is pivotally mounted at its vertex with two arms and extending forward so that when a cassette is inserted and pushed in against both arms, the latter are splayed apart and the spring pivots and snaps the cassette into a "home" position in which it is retained by a cooperating means on the cassette and the compartment.

Abstract: A tape supply cartridge for supplying tape and ribbon to a lettering apparatus having a mechanism for creating a lettering force and a mechanism for positioning a character to be lettered into lettering position. The cartridge includes an improved device for advancing and assuring alignment of the tape and an improved mechanism for interfacing and aligning the cartridge with respect to the lettering machine.

Abstract: An ink ribbon cassette has a box-shaped ribbon container for housing an endless ink ribbon and a ribbon protector positioned between a sheet of print paper and the ink ribbon exposed between ribbon guide arms. The ribbon protector is elongate in shape and has a pair of holes defined in the opposite ends thereof and a central hole. The ribbon protector is mounted in position by fitting the end holes thereof over projections on the ribbon guide arms. The ink ribbon cassette also has a pair of holders for preventing the mounted ribbon protector from being detached from the ribbon guide arms. During a printing operation, the ink ribbon is pressed against the sheet by a print head through the central hole in the ribbon protector.

Abstract: A ribbon cassette cartridge detachably mounted to an image forming apparatus includes a multi-color ribbon wound around a pair of rollers mounted inside the cartridge. The cartridge has a lid which is opened to exchange the ribbon and roll shafts. The cartridge also includes a locator slot adapted to detachably mount the cartridge on a cooperating holder in the image forming apparatus. Holding means are provided in the cartridge to prevent the rollers from rotating when the cartridge is not mounted on the image forming apparatus.

Abstract: A user-friendly ribbon cartridge to house and to facilitate handling a wide thermal transfer ribbon for a thermal color printer is composed of first and second casing sections which define a slotted let-off tube and a slotted take-up tube and turnbar. A pair of casing end pieces connect the corresponding ends of the casing sections so that they are juxtaposed with their axes parallel to one another so as to define a plane and the turnbar is spaced parallel to that plane so that a stretch of ribbon wound about cores rotatively mounted in the tubes can extend out through the tube slots and over the turnbar creating a large unobstructed planar ribbon area that is accessible from both sides for printing. A handle and latch member integral to one of the end pieces facilitate positioning the cartridge properly in the associated printing apparatus and locking it in place during printing.

Abstract: The ribbon (17) has an external run between the type element (25) and platen of a daisy-wheel typewriter. This run stretches between terminal members (59) which protrude from side arms (33 and 34) of the cartridge casing (18) and are fixed to the distal ends of arms (39, 41) pivotally mounted in the casing (18) at (52). The arms (39, 41) are biased downwardly by wire springs (67) to expose the typing line. Ribbon lift levers of the typewriter raise the arms simultaneously to position a selected one of three tracks on the ribbon at the level of the typing point. The terminal members (59) slide on guides (62) at the ends of the side arms (33, 34), constraining the external ribbon run to lie always within and translate within a single plane. The edges of the guides (62) are curved so that the tilt of the terminal members (59) varies as they move up and down, in such a way as to maintain the ribbon tension uniform across the width of the ribbon (17).