Abstract: A flexible member is mounted in an inked ribbon cartridge such that it presses a high friction pad against a cartridge wall between a ribbon entry aperture, and the nip of a take-up spool and an associated drive wheel, thereby to apply a drag force on and to smooth out ribbon passing between the pad and cartridge wall in advance of winding on the take-up spool.In one embodiment a cantilever member formed with the cartridge is flexed by a cam on the cartridge cover to produce pressure on the friction pad secured to the member. In another embodiment, the member is wedged between spaced abutments in the cartridge such that overcentering action applies pressure to the friction pad.

Abstract: A ribbon cartridge having a supply spool (3) and a take-up spool hub (27) to receive ribbon (1). A section (49) of a wire (32) extends from the mounting post (33), with its pointed end resting against the take-up hub (27). Movement in the take-up direction causes a sliding action. Attempted unwinding causes the end to dig into the take-up hub (27) so that the wire section (49) immediately prevents unwinding.

Abstract: An ink ribbon cassette for impact type printers comprises an ink roller of plastic sponge impregnated with ink and an endless type ink ribbon contacting with the ink roller. The ink ribbon is provided with a proper tension by a leaf spring member. At the time of assembly, the pressure of the leaf spring on the ribbon is not yet impressed. After the setting of ribbon, the bow-shaped leaf spring is reversed to opposite side in a snap action, being pushed from the outside, thereby to impress the tension. In another example, when the ink volume impregnated in the ink ribbon decreases after long use of the cassette, pressure is applied to the ink roller by the spring member, by changing the side of it bow part and squeezing ink to transfer to the ink ribbon, thereby prolonging the service time of the ink ribbon.

Abstract: A tape cassette for use with a thermal printing apparatus includes a cassette housing; supply and take-up reels rotatably mounted in the cassette housing; tape having a pigment thereon wound about the supply and take-up reels and having a segment extending between the reels, the length of the segment being adjustable; a hollow projecting portion extending from the cassette housing and having a free end at which a first guide pin is connected; a second guide pin moveably mounted, in a sliding or pivotal relation, with respect to the cassette housing for guiding the segment of tape; and optionally, a tape drawing member to which the second guide pin may be connected and which is moveable with respect to the cassette housing for adjusting the length of the segment of tape.

Abstract: A cartridge which contains two spools. The supply spool has wound about it a printing ribbon and the take-up spool being used for wrapping the used ribbon. The cartridge has a ribbon exit at one location and a ribbon entry at a remote location to define a path for the ribbon to pass therealong. Two drive gears are engaged with each other and a pressure roller. The drive gears are located and their lower portions are configured to engage the respective drive shafts of various printers. When the first drive gear is driven by a printer, the second gear, which includes the drive wheel, rotates in the opposite direction of the drive shaft of the printer. When the second gear is driven, the integral drive wheel rotates in the same direction as the drive shaft of the printer. The pressure roller is provided with internal flexible spokes, or springs, and provides a self-adjusting bias against the drive wheel to drive the ribbon and provides an extremely efficient pinching action.

Abstract: A brake mechanism for controlling a ribbon spool wherein a brake member is disposed in braking relationship with the spool for retarding rotation thereof. The brake member has a brake actuator projecting therefrom. An elongated follower pivotally bears against the spool to follow any decrease in the diameter thereof. The follower has an adjustment member which creates a cammed relationship with the brake actuator for progressively moving same and decreasing the brake torque as the follower pivotally moves in response to a decrease in spool diameter. This adjustment member is positioned to impose either a zero or a minimum torque on the brake member when the spool is empty. When in this empty-spool position, the adjustment member can be initially adjusted in a direction substantially parallel to the radial direction of the brake actuator so as to not affect this zero or minimum brake torque.

Abstract: A ribbon cartridge in a movable print point printer remains stationary while the ribbon moves to and from the print point along a path of fixed length. The path length is established by a first flexible leader which extends from the cartridge to the print point and a second flexible leader which extends from the print point back to the cartridge. The cartridge includes a supply reel for storing ribbon before the ribbon advances to the movable print point and a take-up reel for storing ribbon after it returns from the movable print point. The flexible leader comprises a steel member having a transverse curvature for preventing the leaders from assuming a reverse curvature and maintaining a curvature of substantially constant radius.

Abstract: A ribbon loading system for a printer utilizes a ribbon cartridge that includes a container enclosing two coaxially arranged ribbon reels. By providing flexible blades in the floor of the container, the reels are urged toward a top cover where relative movement is restrained. Upon loading of the cartridge, camming arms enter apertures in the container and are moveable to a clamping position to draw the blades from the ribbon reels and allow free rotational movement.For a presently preferred implementation, the structure including the camming arms is coupled through linkages to clear the ribbon threading path and thereby facilitate ribbon insertion.

Abstract: A ribbon feed system for a matrix printer utilizes metering rollers located on the printhead carrier to maintain a substantially zero ribbon velocity relative to the receiving medium with an on-carrier ribbon feed. By coordinating roller rotation with carrier motion, relative motion that would tend to cause smearing during mark formation is avoided. For printers that inject current into the ribbon to cause printing, friction drag is reduced and tension control is simplified by collecting current at the metering rollers for return to the printhead energizing circuitry. Such dual use of the metering rollers takes advantage of the firm intimate contact that exists for metering to establish a high quality electrical connection. A tension controlled brake at the ribbon supply serves to assure tensions are held within a narrow range at the printhead with such a ribbon metering system.

Abstract: An ink ribbon cartridge is provided with means to control ribbon tension which takes the form of an O-ring driven by the supply spool which is trained around a drag post. When ribbon is to be drawn from the supply spool as by ribbon feed mechanism operative incident to a print action, the rotation of the supply spool is resisted by the drag or friction between the O-ring and the post. The drag force to be overcome to rotate the supply spool is low and does not vary significantly from full to empty supply spool. The resilience of the O-ring also stores energy which acts oppositely on the supply spool when the force to draw off ribbon is removed.

Abstract: A typewriter ribbon cassette contains a feed spool and a take-up spool which are both displaceably arranged in guide slots in the cassette housing. The guide slot for the feed spool leads to a control corner edge opening into an enlarged recess. The feed spool is biased with a spring force towards the control edge of the slot during unwinding of the ribbon roll, so that, when the feed spool has overrun the control edge, the spool is pivoted into a switching position which can be detected by a monitoring device for signalling an end of tape state of the ribbon roll. The hub of the feed spool is provided with a guide pilot for sliding along the guide slot which has a cornered plan profile for holding the hub in a straight line path along the slot until after the control edge is overrun.

Abstract: A cassette for storing a ribbon having a top portion and a bottom portion. The top portion has a front area having a print station area thereat and a rear area, and also has a first resilient arm having one end extending from the front area to the rear area and also having a free end. A ribbon supply reel is rotatably supported on the first arm and the top portion also has a second resilient arm formed therewith having a free end which engages the rim of the supply reel to form a drag thereon. The ribbon from the supply reel passes around the free end of the first arm, around a ribbon usage sensor, to the print station and is withdrawn back into the cassette by a take up reel located underneath the supply reel, with the take-up reel driven by a spindle.

Abstract: Ribbon lifting apparatus for a printing device having a print wheel and a ribbon cartridge. The lifting apparatus includes a pair of ribbon guides for supporting an exposed portion of a ribbon extending from an outlet opening of the ribbon cartridge to an inlet opening thereof. The pair of ribbon guides are supported by respective pairs of supporting levers which are swung in a plane parallel to the face plane of the print wheel. The pair of ribbon guides are lifted so that the lifting movement of the guides causes variation of a distance therebetween for keeping the path of the exposed length of ribbon substantially constant.

Abstract: A ribbon cassette is fastened on one side of a printer and is operator reloadable. The endless ribbon is loaded in coil form and is driven from the cassette in a path past the printing station of the printer and back into the cassette where it assumes a random form corresponding to a stuffing type cassette.

Abstract: A ribbon cartridge for use in a high speed band printer includes a body having a ribbon storage compartment where the ribbon is contained in a multiplicity of serpentine folds. The body has a ribbon inlet and an outlet end and guide arms extend from the inlet and outlet ends to guide the endless ribbon into and out of the cartridge and to define an exposed loop of the ribbon between the outermost end of the guide arms. The outlet end and outlet arm of the cartridge is formed to define a ribbon inverting device which serves to invert the ribbon 180.degree. each time the ribbon passes through the device.

Abstract: Ribbon feed from a ribbon supply spool is controlled in an incrementing ribbon feed system by a pawl and ratchet brake device actuated by ribbon tension. The mechanism utilizes a single-band spring member to control ribbon tension and ribbon metering.

Abstract: A ribbon cartridge for use in high speed cartridge type printers, in which the ribbon is enclosed in the cartridge, and the entire cartridge must move at extremely high speeds. The cartridge is in a generally U-shaped case with the base of the U comprising a ribbon storage volume. One of the arms of the U is called the exit arm, and the other called the re-entry arm. Positive pressure roller means is provided for driving the ribbon into the storage volume, thereby pulling ribbon out of the storage volume at the other end, out through the exit arm where a pad of felt, or the like, is used to provide suitable tension. The ribbon then moves across between the two tips of the U arms, down and into the re-entry arm. An ink reservoir is provided in the re-entry arm, comprising a wedge of felt or similar material and including means to apply marking fluid, such as stamp pad ink, to the wedge.

Abstract: A ribbon cartridge is provided to be used in a high speed impact printer having means for driving only one reel in the ribbon cartridge, the take-up reel. The ribbon cartridge comprises a cartridge housing having an open end, and supply and take-up reels rotatably mounted in said housing. The supply reel supports an inventory of unused ribbon web which runs from the supply reel to the take-up reel. The rib is mounted in the cartridge housing facing the open end in a position closer to the supply reel than to the take-up reel.The printer into which the ribbon cartridge is to be inserted contains driving means for driving only the take-up reel. The printer receiving means into which the cartridge is to be inserted includes a stop element disposed so as to block the rib to stop the engagement of the cartridge and the receiving means when the cartridge is being inserted in a direction towards the undesirable engagement of the drive means with the supply reel rather than with the take-up reel.

Abstract: A continuous ink ribbon cassette for, for example, a serial printer in which a ribbon is kept in stacked loops in a vertical housing and is twisted on leaving and re-entering the housing so as to bring it into a vertical plan as it passes a print head. The ribbon leaves the housing through an opening at one end and passes round a vertical roller at the other end. After passing the print head, the ribbon is returned to the housing via a second vertical roller at the opposite end and an opening at the opposite end. The ribbon thus executes a figure 8 configuration and has the entire length of the housing in which to change its attitude from horizontal to vertical or from vertical to horizontal.

Abstract: A ribbon cassette or cartridge comprising a housing having a hub element supporting a core having a ribbon wound thereon, such as a typewriter or printer ribbon, and adapted to releasably engage said core for rotation thereon. The hub element comprises at least two portions, at least one portion being fixed to the housing of said cassette or cartridge, and at least one other portion which is attached for movement between a locking position, in which it makes frictional engagement with the ribbon core to substantially prevent rotation of said core on said hub element, and a release position in which it is moved out of frictional engagement with said ribbon core to permit rotation of said core on said hub element.

Abstract: A typewriter correction tape cartridge for holding and feeding correction tape for a correcting typewriter is improved by the addition of a beam spring cantilever supported such that one end of the beam spring wipes the correction tape onto the takeup spool. This will act to eliminate bubbles, wrinkles and crimps in the tape as it is placed in a new convolution on the spool and will thus reduce the outside diameter of the ultimate disc of used tape. The advantage of this spring is that a reduced size cartridge may be used while utilizing the entire volume of tape supplied on the supply side of the cartridge and, secondly, a more reliable takeup is accomplished due to the elimination of irregularities in the takeup disc.

Abstract: A ribbon loading system for a printer of the kind having a moveable printhead carrier establishes a ribbon loading position for the carrier at one end of the carrier travel axis. In response to an operator initiation, the printhead carrier is driven to the loading position where the ribbon cartridge is operator mounted at a fixture adjacent the printhead. The cartridge includes a path defining section that extends to arrange a loop of ribbon around the distal side of the printhead, effectively threading the ribbon. Subsequent carrier movement is selectively coupled to the ribbon to provide ribbon drive motion.For a preferred cartridge implementation, the path defining section is detachable to travel with the printhead carrier and includes ribbon guides for defining at least a portion of the ribbon path around the printhead during printing. The preferred detachable section is held to a bulk ribbon supply section of the cartridge by a catch which is automatically released by mounting the cartridge.

Abstract: In a typewriter ribbon cartridge, it is necessary to maintain tension on the span of ribbon extending outside the cartridge to prevent tangling and to insure high print quality during machine operation. One technique for insuring that adequate tension is maintained is disclosed herein as an anti-backup back check device. Connected to the takeup spool of the ribbon cartridge is a disc member supporting thereon a pair of thin flexible resilient arms with outwardly oriented pointed ends. These ends formed in the shape of points engage ratchet teeth formed around the interior surface of a cylinder. The cylinder is formed as a part of the ribbon cartridge and, thus, is permanently positioned and fixed with respect to it. As the takeup spool disc and arms are rotated by the ribbon feed mechanism, the arms will flex and permit a rotation of the disc and takeup spool with a minimal drag force.

Abstract: A releasable ribbon locking device is used to keep a ribbon taut in a typewriter ribbon cartridge. The device includes a locking member carrying a blade or brake urged by a spring into abutting relationship with a rotatable ribbon supply support to prevent unwinding of fresh ribbon from the supply. A lock release member is movably coupled to the locking member and supports a ribbon tensioning element in engagement with a portion of the ribbon extending from the ribbon supply. In operation, a ribbon feed mechanism pulls on the ribbon which moves the lock release member through the tensioning element and correspondingly moves the locking member to rotatably free the ribbon supply support from abutment with the brake and allows the ribbon to unwind from the supply.

Abstract: In ribbon cartridges which are utilized in cooperation with a spacially fixed driving member engageable with a takeup spool at its periphery to feed the ribbon, it is necessary for the takeup spool to translate away from the spacially fixed driving member as the spool accumulates ribbon and the consumed ribbon forms disks of increasing diameter. A frangible portion of the cartridge may be utilized in conjunction with its transverse engagement with an extending axle coaxial with the takeup spool to resist the movement of the takeup spool into the chamber of the cartridge except as is forced by the increasing diameter of the ribbon disk formed on the takeup spool. The frangible section of the cartridge may be formed either during molding operation or as an additional member being added during assembly and will break or tear as the axle of the takeup spool is forced away from the end of the cartridge by the increasing diameter of the ribbon disk and the force of a driving member engaging the ribbon periphery.

Abstract: A printhead assembly for a typewriter of the kind that swipes a printhead along a ribbon in producing marks on a receiving medium, is mounted to pivot and includes a ribbon guide that serves to wrap the ribbon around the trailing side (for a forward printing direction) of the printhead. The assembly is positioned to permit the printhead to be rotated to a normal printing position at a printing line. By so arranging the ribbon path that the ribbon directions for arrival and departure of the assembly intersect the pivot axis, essentially zero resultant torque may be applied to the assembly by ribbon tension forces and the printing pressure at the receiving medium is, accordingly, unaffected by ribbon tension variations.

Abstract: A microcomputer controls a ribbon drive assembly in a high speed wire matrix printer to eliminte ribbon slack, to insure proper ribbon positioning and to conduct diagnostics in conjunction with turning on the printer such as start-up time each day and after replacement of the ribbon with a new ribbon, the diagnostics checking to be sure that a ribbon is actually in the proper position, that it is threaded across the print line and also checking for proper operation of the ribbon drive, logic, and electronics. Tests are also made for proper ribbon drive during normal ribbon feeding operations.

Abstract: An imprinter having a single driving device for controlling both the movement of the heated printing head and the intermittent advancing movement of the pigmented ribbon. The single driving device, which preferably comprises a reciprocal fluid pressure cylinder, causes the advancing and retracting movement of the printing head. A motion-transfer mechanism drivingly joins the printing head to the take-up reel for the pigmented ribbon. This mechanism is of the one-way type so as to effect rotation of the take-up reel, and advancement of the pigmented ribbon, only when the printing head is being retracted. This mechanism also employs a lost-motion connection therein so that the rotation of the take-up reel is delayed relative to the initial retraction of the printing head, whereby the printing head is initially moved out of engagement with the ribbon prior to the intermittent advancing thereof.

Abstract: A printer having an ink ribbon with a bidirectional ribbon drive in which a pair of stepper motors have their windings cross-coupled so that a drag current flows through one stepper motor to apply drag torque to the ribbon when the other stepper motor is operated for driving.

Abstract: A stuffed ribbon cartridge for a serial impact printer includes flexible leaders for guiding the ribbon from a stationary storage position to a movable print point. In order to place tension on the ribbon which is stored in the cartridge in a stuffed condition, a clip which pinches the ribbon so as to produce a drag force on the ribbon is located adjacent the print point and spaced from the cartridge by a substantial length of the flexible leader.

Abstract: An improved ribbon tensioning means is disclosed in which a spring-loaded gear rack is in engagement with a gear wheel formed on a spool of tape to be unwound. The gear rack is provided with sufficient travel in the direction opposite to that of the spring force that the teeth thereon can be disengaged from those on the gear wheel if the wheel is rotated a sufficient distance, thus constantly providing tension to a tape or ribbon wound on the spool.

Abstract: An ink ribbon unit for printers in which the inking roller is selectively brought into engagement with the ribbon thereby to avoid over-inking.

Abstract: In a ribbon cartridge for retaining and supporting a ribbon in a typewriter, the cartridge comprising spaced apart top and bottom walls and a sidewall joining the top and bottom walls adjacent the periphery thereof to form a chamber. The sidewall of the cartridge is discontinuous at predetermined locations to form at least entrance and exit apertures for the ribbon, and at least a ribbon take up spool is provided in the chamber in communication with the ribbon entrance aperture to take up used ribbon passing through the entrance aperture.

Abstract: A printer ribbon cartridge device includes structure for maintaining tension of a printer ribbon which is supplied and contained on a supply spool having an automatic brake for preventing unwinding thereof whenever the cartridge is not installed on a printer. Ribbon guide structure is provided so that the printer ribbon will be confined to a desired path, positive capstan feed rollers are provided of intermeshing gear type for positive feed of the printer ribbon and further gearing is provided to positively drive a slipping clutch element for a take-up spool. A one-way locking pawl also engages with the gearing to prevent rewinding of the printer ribbon after use and thereby prevent the reuse of same. The slip clutch for the take-up spool employs a gear driven input hub member provided with a central recess thereacross for supporting a deformed ring in an oval shape for driving contact by portions of the other circumference thereof against the inner surface of an outer take-up spool hub member.

Abstract: In order to enable ink ribbon transport and ribbon reversal on the one hand and on the other hand the withdrawal of the printing head from the platen to be performed by means of only a single motor, a pawl-and-ratchet device is provided between the drive gearwheels for the reel holders and the drive motor. The cord for the withdrawal of the printing head is connected to a deflection lever which follows the profile of a cam disc of a cam mechanism, which is connected via a further pawl-and-ratchet device to the common shaft driven by the electric motor. The two pawl-and-ratchet devices drive in opposed directions. The common drive motor is reversible and is electrically controlled by the cam mechanism.

Abstract: An ink ribbon cartridge for a printing machine of the type which includes a carriage moving in a direction parallel to the line of typing and a needle printing head, which can move on the carriage perpendicular to its direction of movement to advance and retract the head with respect to that on which printing is effected. The cartridge is supported by the carriage and includes a container having a cover, a base and a series of inner walls which bound an opening to house the needle printing head. The cartridge comprises two arms to guide out a portion of an inked ribbon near the head. The container arranges the ribbon in loose folds and supports a pair of rollers for the single directional feed of the ribbon. A tensioning unit in the cartridge includes a roller borne by a coupling having two ends housed and guided in corresponding slots of the base and of the cover, substantially parallel to the direction of movement of the head in relation of the carriage.

Abstract: In order to maintain constant tension on a relatively long expanse of ribbon stretched along the carrier path in impact printer apparatus having off-the-carrier ribbon drive and feed, apparatus is provided for driving a first and a second reel in forward and reverse directions, each reel being adapted to support a portion of an inventory of a ribbon web running along said carrier path from one of said reels to the other at a constant speed differential between the portion of the web being taken up on one of the reels and the portion of the web being supplied on the other of said reels irrespective of the drive direction which comprises a first inelastic drive belt for peripherally non-slip driving the web portion on the first reel and a second inelastic drive belt for peripherally non-slip driving the web portion on the second reel.

Abstract: This invention relates to apparatus for marking strip material such as cinematographic film, the apparatus comprising means for feeding the film from a film supply station to a film take-up station via a printing station, means for feeding a tape carrying transferable marking material from a tape supply station to a tape take-up station via the printing station, said printing station including two movable members one carrying a printing block and the other carrying a back-up platen, the apparatus being arranged such that at said printing station the film and tape move between said two members in a superimposed relationship and such that when the printing block and platen are moved into co-operating, adjacent, relationship, selected print elements on the printing block causing marking material to be transferred from the tape to the strip material thereby to mark or print the strip material with data indicated by the selected print elements.

Abstract: A ribbon cartridge comprising a housing including a first cavity in which an ink ribbon in the form of an endless loop is received in irregular form, and a second cavity in which a tape in the form of an endless loop of high polymer film or metal film and having a width which is substantially equal to that of the ribbon is received in irregular form. The housing has an inlet and an outlet, which are common to both the ribbon and the tape and which communicate with both the first and second cavities. Either the ribbon or tape is drawn to the outside of the housing through the common outlet from their associated cavity and is then again inserted into the corresponding cavity through the common inlet. Intermediate the inlet and the outlet, both the ribbon and the tape are maintained in substantially overlapping relationship so as to be subject to the action of a printing element.

Abstract: A cassette-type ink ribbon device for a printer wherein the inked ribbon is carried in a throw-away magazine operatively disposed within and wholly independent of the cassette body. The cassette body carries all of the drive components and, hence, replacement of the magazine revitalizes the cassette at minimum expense.

Abstract: A mechanism for feeding an ink ribbon comprises a pair of ratchet wheels for taking up the ink ribbon, a feed pawl for rendering an intermittent movement to said ratchet wheels, a lever for preventing the backward movement of said ratchet wheels, a reverse mechanism for said ink ribbon, wherein a stopper which engages or disengages with said supply ratchet wheel in response to the movement of said lever is provided, thereby, through preventing the slack of the ink ribbon which occurs when the ink ribbon is taken up, the feeding of the ink ribbon is stabilized and the printing quality is improved.

Abstract: An anti-fold apparatus for high speed printers to prevent the folding or creasing of a printer ribbon riding over rollers. The rollers each have spiral angular serrations thereon, and are mounted in two pairs with each roller in a pair having one end abutting the end of the other, and each being mounted at an angle to the elongated center axis of the other, so that a printer ribbon rolling thereon is directed away from the abutting ends of each pair of rollers to prevent creasing therein. A linkage connects the two pairs of rollers at their abutting ends for shifting the angular position of each pair simultaneously between first slanted positions, when the ribbon is moving in one direction, and second slanted positions, when the ribbon is moving in the reverse direction. The linkage is actuated by solenoids, actuated by the reversing of the ribbon.

Abstract: In order to advance an inked ribbon in a printing apparatus in which a printing carriage mechanism moves across the width of a platen, one-way brakes are placed on ribbon guide rollers on the printing carriage mechanism to permit relative movement between the printing carriage mechanism and the inked ribbon as the printing carriage mechanism is advancing from left-to-right across the paper. One-way brakes are placed on return rollers in the ribbon path in order to prevent the inked ribbon from moving with respect to the platen as the printing carriage mechanism is moving from left-to-right across the paper. When the printing carriage mechanism moves from right-to-left in order to return to the left-hand margin, the one-way brakes on the ribbon guide rollers on the printing carriage mechanism apply substantial friction to the inked ribbon and drag the inked ribbon with the printing carriage mechanism as the printing carriage mechanism returns from right-to-left.

Abstract: A ribbon cartridge for use in a typewriter and/or printer which cartridge has a supply of ribbon which is fed from within the cartridge across a gap where it is used by a typing or printing mechanism and returned to a driven take-up area, is disclosed, which cartridge includes an improved tensioning and locking apparatus, comprising a mechanically biased movable member positioned between the ribbon supply and its outlet, so as to bear against the ribbon, which member automatically takes up small overruns of ribbon from a supply and releasably locks the ribbon by means of friction contact when large overruns occur during use.

Abstract: A low cost cartridge for supplying inked ribbon to the printing station of an associated printing device. The cartridge includes an internal tensioning mechanism for maintaining the length of inked ribbon positioned in the printing station at a constant tension independently of the quantity of ribbon remaining on the supply reel in the cartridge. The tensioning mechanism includes an elastic endless belt disposed in a closed path about a plurality of freely rotatable rollers, the path having an interference region in which portions of the belt are engaged by a portion of the outer layer of supply reel mounted ribbon and are deflected thereby to produce a drag force on the supply reel which varies with the pulling force required to withdraw ribbon from the supply reel.