Method and Apparatus for Applying Ink to Ribbons

The present invention relates to a method and apparatus for applying ink to used inked ribbons, such as are employed in printing apparatus and more particularly in business machines and computer peripheral equipment.

In one aspect, the present invention provides a method for applying fresh ink to a used inked ribbon comprising the steps of applying heat to the ribbon to expand and unwrinkle or smooth the fibers of the ribbon, applying ink under pressure to at least one side of the ribbon to impregnate the ink into the interstices of the fibers of the ribbon and again applying heat to the ribbon to spread the ink and smooth the ribbon. Preferably, ink is applied under pressure to both sides of the ribbon.

Preferably, the ribbon is initially heated on one side by passing it under tension over a heated rotating roller thereby to flex and heat the ribbon. After the ink is applied, final heating of the ribbon is effected by applying heat to the other side of the ribbon by passing it under tension over another heated rotating roller to spread the ink and smooth the ribbon.

Advantageously, the inking of the ribbon under pressure is effected by passing the ribbon between two ink transfer rollers, each of which receives ink from a roller rotating in a trough of ink.

In another aspect of the present invention, there is provided apparatus for applying fresh ink to a used inked ribbon, including a frame, means carried by the frame for rotatably carrying a core thereby enabling the ribbon to be unwound therefrom, a first roller for applying heat to one side of the ribbon and over which the ribbon passes as it is unwound from its core, second and third rollers carried by the frame for applying ink to opposite sides of the ribbon as it passes between them after being heated by the first roller, a fourth roller carried by the frame for contacting and applying heat to the side of the ribbon opposite the one side thereof, and means for passing the ribbon over the first, second, third and fourth rollers and winding the inked ribbon on a second core.

The accompanying drawings illustrate a preferred embodiment of the present invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a diagrammatic side elevational view of an embodiment of a re-inking machine illustrating the method of the present invention;

FIG. 2 is a plan view of the machine illustrated in FIG. 1 having parts (specifically the first heated roller and the upper ink roller and trough) broken out and removed for clarity; and

FIG. 3 is a diagrammatic view of a throw-off arrangement for the heated rollers.

Referring to the drawings, a machine constructed in accordance with the present invention includes a frame having two inclined parallel spaced side frame members 1 having their upper ends supported by columns 2 which rest on a base member 3. The lower ends of the side frame members 1 also rest on base member 3. Between side frame members 1 are arranged, in the direction of travel of a ribbon to be re-inked, a shaft 4 for supporting a core 5 containing a ribbon R to be re-inked, a first heated roller 6, a second heated roller 8 and a take-up shaft 9 supporting a core 10 (FIG. 2) on which the re-inked ribbon is re-wound. The rollers 6 and 8 contain electrical heating elements and electrical power is provided thereto by connections 33.

The ribbon R, to be re-inked and supported on core 5 (FIG. 2), is positioned between chucks 11 on shaft 4. Shaft 4 is thus split into two parts. Ribbon R passes from core 5 over the first heated roller 6 with its lower surface (as viewed in FIG. 1) in contact with roller 6. Ribbon R then passes through the re-inking station 7.

In accordance with the present invention, re-inking station 7 comprises two pairs of side frames 7a and 7n. The side frame 7a supports an ink-containing trough 7b in which an ink roller 7c rotates in contact with a transfer roller 7d. Roller 7d applies ink to the lower side of ribbon R. A further ink roller 7a rotates in an ink-containing trough 7f supported by side frames 7n. Roller 7e applies ink to the other or upper side of the ribbon through a transfer roller 7g. Thus, ribbon R passes under pressure through the nip between the two ink transfer rollers 7d and 7g. Ribbon R then passes over heated roller 8 supported on shaft 12, and is then re-wound on the take-up core 10 held by chunks 13 on shaft 9. Shaft 9 is thus split into two parts similarly as shaft 4. Shaft 12 is mounted between two parallel swing arms 39.

More specifically, ink roller 7c rotates in ink trough 7b in contact with a metering roller 7h which meters the quantity of ink applied to the transfer roller 7d. Roller 7d, in turn, applies ink to the lower side of ribbon R. A similar arrangement including a metering roller 7j is provided for ink roller 7e. Ink roller 7e contacts the transfer roller 7q which applies ink to the upper surface of ribbon R. Ink is fed to the troughs through an input 7p from a pump. Ink overflow from the troughs flows through a pipe 7m to the ink reservoir which feeds the pump.

A control for metering the ink is illustrated in FIG. 1. Particularly, doctor blades 7r and 7s are arranged adjacent the ends of transfer rollers 7d and 7g to remove surplus ink from those marginal edge areas of ribbon R which have not been subject to de-inking in use and which therefore already have a substantial full content of ink.

As illustrated in FIG. 2, the left-hand part of the shaft 4, which supports the core 5 carrying the ribbon R to be re-inked, is axially slidable in a bearing block 14. A compression spring 15 is arranged around shaft 4 between bearing block 14 and a collar 4a secured to the shaft. The right-hand part of shaft 4 extends through a bearing block 16 into a further section of the machine, generally indicated at 17, and carries two spaced collars 4b defining a gap which receives the end of an arm 4c mounted on the output shaft of a gear motor 18, for purposes described hereinafter. The machine section 17 also contains a drive mechanism for the various rollers, as will be described later.

In a similar manner, the left-hand part of shaft 9 is axially slidable in a bearing block 20. A compression spring 21 surrounds shaft 9 between bearing block 20 and collar 9a attached to the shaft. The right-hand part of shaft 9 extends into drive section 17.

The axially slidable left-hand parts of the shafts 4 and 9 as illustrated in FIG. 2 enable insertion and removal of the cores 5 and 10 between the respective chucks 11 and 13.

As indicated by the dashed lines in FIG. 1, both the heated rollers 6 and 8 and the upper ink transfer roller 7g throw off for easy threading of ribbon R and, to this end, the rollers 6 and 8 are mounted on swing arms, described hereinafter with reference to FIG. 3.

The drive section 17 of the machine comprises a drive shaft 22 which drives roller 7c and which carries a gear 23 in mesh with a gear 24a driven by a main drive motor 24. A further gear train, not shown, is provided for rotating ink roller and 7e. Shaft 22 also carries a pulley 25 and a drive belt 26 passes about pulley 25 as well as about a pulley 27 carried on the right-hand end of shaft 9. Pulley 27 forms part of a clutch mechanism including a friction disc 28 and a further pulley 29. The clutch parts are urged together by a tension spring 30 disposed about shaft 9 between pulley 29 and an adjustable end stop 30a. A further drive belt 32 extends from pulley 29 to a pulley 31 carried by the right-hand part of shaft 4. A manually operable rewind crank handle 31a is also provided on the end of shaft 4. Both of belts 26 and 32 are crossed in their path between their supporting pulleys in order to provide the desired directions of rotation to pulley 27 and 31.

In operation, motor 24 drives shaft 22 carrying roller 7c and also rotates pulley 25 thereby driving shaft 9 through belt 26 and pulley 27 to take up ribbon R on the core 10 held between the chucks 13. As ribbon R is wound about core 10, it is unwound from core 5 and rotates the shaft 4. Simultaneously pulley 31 rotates in the opposite direction by the back drive provided by pulley 29 and crossed belt 32 to take up slack in the ribbon feeding off core 5. The amount of back drive is adjusted by varying the tension of spring 30 on the clutch 27, 28, 29 by means of an adjustable end stop 30a, to provide a substantially constant winding tension and to compensate for variations caused by the changing diameter of the ribbon on the core as it is transferred from core 5 to core 10.

Thus the clutch mechanism automatically controls the tension of the ribbon as it passes through the machine within a manual range of adjustment to ensure the desired tightness of ribbon R as it is wound on core 10.

Consistent with this previous disclosure, the operation of the drive and tension mechanism will be more specifically disclosed.

As is apparent from FIGS. 1 and 2, the ribbon is driven between ink transfer rollers 7d and 7g. Roller 7d is, in turn, driven by ink roller 7c (shown in FIG. 1), which is in turn driven by shaft 22. Therefore, the pulley 25, linked to ink roller 7c through shaft 22, rotates in a direction opposite that of shaft 9. As shown in FIG. 1, shaft 9 rotates counterclockwise to collect the ribbon on the take-up core 10. Therefore, the belt connecting pulley 25 with pulley 27 is twisted as shown in FIG. 2 to reverse the direction between the two pulleys. In that manner, the drive from the motor 24, transmitted through the gear 23 to shaft 22 and pulley 25, is applied to the shaft 9, turning the take-up core 10 in a manner to exert tension on the ribbon.

The shaft 4, on which the supply core 5 is detachably affixed, is driven by the unwinding of the ribbon from the supply core. Pulley 31, affixed to the shaft 4, rotates in the same direction as shaft 9 and the take-up core 10. The pulley 31 is, however, linked to pulley 29, rotatably mounted on the shaft 9. As shown in FIG. 2, the belt linking pulley 29 and pulley 31 are twisted to reverse the direction of rotation. Therefore, the rotation of shaft 9, transmitted to the friction material 28 between pulley 27 and 29, resists the rotation of the pulley 31.

The friction between the pulleys 29 and 27 transmits the force of the rotation of shaft 9 back to shaft 4, providing the back drive previously mentioned. Similarly, the rotation of the pulley 29, in opposition to the pulley 27, decreases the force applied to the take-up core 10 through the shaft 9. The tension, being balanced by the interrelationship of these driven shafts, is automatic since the slippage between pulley 27 and pulley 29 is predetermined by the tension in the spring 30. The length of the spring 30 is manually controlled but the slippage induced by the spring, once set, is constant. The tension in the ribbon, however, is not constant due to the different forces applied to shafts 4 and 9, respectively.

The opposed rolls 7d and 7g drive the ribbon through the apparatus at a constant linear rate. As the supply core 5 is depleted of ribbon, its radius decreases. Therefore, its rotational speed increases. The increase in rotational speed provides an increased resisting force applied through the friction material 28 to the pulley 27. This decreases the tension applied to the take-up core 10. In that manner, the tension in the ribbon is automatically adjusted for the diameters of the ribbon on the respective cores.

A photoelectric cell 34 carried by a mounting 35 is arranged to detect one edge of the ribbon R as it is fed through the machine and provide a signal to a control mechanism to maintain the alignment of the ribbon as it passes through the machine.

More specifically, photoelectric cell 34 receives light from a light source, not shown, through a slit 35a in the mounting 35. The photocell controls a series of relays which in turn control the direction of rotation of electric gear motor 18. The arm 4c attached to the output shaft of this motor is thereby displaced and, since its free end is closely located in the gap between the collars 4b, this displacement causes axial movement of the shaft 4 in bearing block 16. This provides lateral or axial control over chucks 11 between which the core 5 is held under the force of spring 15. The direction of this lateral control is determined by the position of the edge of the ribbon R adjacent the slit 35a in the mounting 35. If the lateral control is such that the edge of the ribbon covers the slit, light is cut off from photoelectric cell 34 and it switches the relays to reverse the direction of rotation of the gear motor 18. The arm 4c is then moved in the opposite direction and hence shaft 4 is axially displaced to move the core 5 so that the edge of the ribbon uncovers the slit to again allow light to reach the photocell 34. The system now reverses thereby providing constant correction to maintain the alignment of the ribbon as it passes through the machine. The constant correction previously noted is due to the fact that the edge detection means controls the direction of movement of the shaft 4 with the motor being activated at all times. This minimizes the time from the detection of the edges movement to actual adjustment of the equipment. A motor speed control is provided to compensate for different machine speeds and types and conditions of ribbon being handled.

Means are also provided to automatically shut off the machine at the completion of the re-inking of a ribbon by increased tension on the ribbon when the end of the roll is reached. The torque required to achieve this is adjustable and also operates to detect loose or detective attachment of the ribbon on the core. This arrangement will now be described in conjunction with the throw-off arrangement for the rollers.

The throw-off arrangement for the rollers 6 and 8 is illustrated diagrammatically in FIG. 3. This arrangement comprises an electric motor 36 whose output shaft drives an arm 37 which is connected to the swing arms 38 and 39 carrying rollers 6 and 8 respectively. Once the ribbon has been threaded on the machine, the rollers 6 and 8 are moved into the running position, shown in full line in FIG. 1, by rotation of the electric motor and the arm 37 on which the swing arms are mounted.

In the running position, rollers 6 and 8 deflect the ribbon in its passage through the machine and are held in this position by an adjustable torque control 40 on motor 36 until the ribbon is completely unwound from the core 5. At this point the tension of the ribbon R on rollers 6 and 8 increases and causes the torque control 40 to break loose, thus rotating the swing arms 38, 39 to throw off the rollers 6 and 8 towards the threading position (shown by the dashed lines) and thereby creating slack in the ribbon. The main drive motor 24 is energized through a limit switch which is only closed when the rollers 6 and 8 are in the running position. The main drive motor will thus stop as soon as torque control 40 breaks away and the slack created by this allows the ribbon to stop without pulling away from core 10. If the ribbon attachment to core 5 is defective, the ribbon will pull away from the core. However, the ribbon can then be easily re-anchored to the core to prevent it from coming loose and causing problems during its subsequent use in a printing apparatus.

It will be noted that both sides of the ribbon are re-inked under pressure with a relatively large arc of the ribbon in contact with a pre-metered layer of ink on the surface of the transfer rollers 7d, 7g on both sides of the ribbon. The pressure between these rollers impregnates the ink into the interstices of the fibers and is arranged to be adjustable. Moreover, the inking station 7 provides for accurate metering of the ink by the metering rollers 7h, 7j associated with each ink trough 7b, 7f.

The heating elements associated with each of the heated rollers 6, 8 allow the temperature of the rollers to be adjusted within the range 100.degree. to 300.degree. F.

A fluorescent lamp 41 mounted in a reflector 42 transverse to the path of the ribbon R is arranged to shine light through the processed ribbon between roller 8 and core 13 so that the re-inked ribbon can be visually inspected by an operator viewing the ribbon from the other side.

It will be seen that the present invention provides a method and apparatus wherein re-inking of a ribbon can be accomplished from the front of the machine with all adjustments within easy reach. Furthermore, the ink reservoirs are large and have automatic ink level control re-circulation to cool and filter the ink. When not in use the inking rollers are easily separable to prevent spots occurring on the rollers and the rollers and ink pans can be easily removed for cleaning or replacement.

If desired, the transfer roller 7g can be made adjustable so that it does not apply ink to the ribbon, but is only inked on one side by the lower transfer roller 7d. Such an arrangement may be preferred for the re-inking of light-weight ribbons.

Generally, the ribbons to be re-inked will be nylon ribbons. Ribbons of other materials, of course, may also be treated.

The method and apparatus of the invention may also be employed for initially inking fresh ribbons as well as for re-inking used ribbons as described herein.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.