Technical Field

This invention relates to ink ribbon mechanisms for use in printers, and is concerned in particular with ink ribbon cassettes.

Background Art

In present-day printers, it is common practice to provide and use a ribbon cassette carrying an endless ribbon which is caused to be driven past a printing station. A known kind of ribbon cassette is the stuffing-box type wherein the ribbon is contained within the cassette in random manner and such ribbon is unfolded at the cassette exit and caused to be driven past the printing station and then guided back into the cassette to be folded again in random manner therein. Also, it is known for ribbon cassettes to include ink carrying or containing means operably associated with the ribbon for maintaining or replen¬ ishing a supply of ink for the ribbon for proper and extended-life printing operation.

Ribbon reinking in a cassette can lead to technical problems such as that of maintaining the ribbon in a properly-inked condition throughout the life of the cassette. One attempt at overcoming such problems is described in U.S. Patent No. 4091914 which discloses a ribbon cassette of the stuffing-box type incorporating means for bringing about a delayed and gradual transfer of ink to the ribbon. The cassette includes an ink supply means in the form of a porous roll impregnated with ink, and an ink transfer means in the form of a transfer roller for transferring ink from the porous roll to the ribbon. The ribbon passes partly around the surface of the transfer roller, and, in operation, due to wear on its inner bearing surface the transfer roller is caused to move into contact

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with the porous roll and so cause replenishment of the ink on the ribbon to begin. As operation continues, the wear on the inner surface of the transfer roller continues so that the movement of ink from the porous roll to the transfer roller and the ribbon increases. The outer surface of the transfer roller is grooved to provide a firm engagement of the ribbon therewith and to promote the pick-up of ink from the porous roll.

The ribbon cassette disclosed in the above- mentioned U.S. patent has the disadvantage that the progressive wear on the inner surface of the transfer roller may eventually cause too much ink to be trans¬ ferred to the ribbon and may limit the life of the cassette.

Disclosure of the Invention

It is an object of the present invention to provide a ribbon cassette of the kind including ribbon reinking means, which cassette provides for a con¬ trolled transfer of ink to the ribbon with a view to maintaining the ribbon in a properly-inked condition at all times, and which has a prolonged useful life.

According to the invention there is provided a ribbon cassette for use in a printer, including rotatable driving means for driving said ribbon for use in printing operations, ink supply means, and ink transfer means engageable by said ribbon and in con¬ tact with said ink supply means, said ink transfer means having a plurality of uneven portions on the periphery thereof for carrying ink from said ink supply means to said ribbon upon rotation of said driving means and said ink transfer means with said ribbon therebetween, characterized in that said ink transfer means is driven by said driving means with said ribbon passing therebetween, and in that said ink supply means comprises a first ink carrying element and a second ink carrying element, said ink transfer

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means being in engagement with said second element for obtaining ink therefrom, and said first element con¬ sisting of porous material of one density and said second element consisting of porous material of a greater density and adjacent said first element for transferring ink thereto.

A ribbon cassette in accordance with the present invention may be used in a business machine incorporating an impact printer and which printer may be required to operate at high efficiency for extended periods of time.

Brief Description of the Drawings

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a top plan view of a ribbon cassette incorporating the subject matter of the present invention;

Fig. 2 is a perspective view showing the parts of the ribbon cassette in exploded manner;

Fig. 3 is a sectional view, taken along the line 3-3 of Fig. 1; and

Fig. 4 is a diagrammatic view illustrating the re-inking operation.

Best Mode for Carrying Out the Invention

In Fig. 1 is illustrated a ribbon cassette, generally designated as 10, and having the cover removed therefrom to show the interior structure and the various components thereof in a preferred arrange¬ ment of the subject matter of the present invention. The cassette 10 includes a body 12, preferably of molded plastic material and in the shape of a general¬ ly rectangular flat case (see also Fig. 2), for sup- porting the ribbon thereof and which cassette is adapted to fit adjacent or along the printing station

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of a printer (not shown) . The cassette body 12 in¬ cludes a large cavity or chamber 14 formed in part by a front wall 16 extending nearly the width of the cassette 10, a leftward wall 18 of irregular shape and extending generally perpendicular rearward from the wall 16, and a rearward wall 20 angling toward the right side of the cassette body. While the orienta¬ tion of the cassette 10 itself is not critical to operation of the parts therein, the terms used herein may apply to the orientation of the cassette when installed on a printer and wherein the wall 32, as illustrated in Fig. 1, is nearest the operator when the cassette is placed in a horizontal attitude. In certain printers the cassette may be used in a verti- cal attitude wherein the wall 32 thereof is in a downward direction.

A ribbon 22 of the endless type is provided in the cavity 14 and is caused to be trained and driven therefrom in a path as shown by the arrow 24 at the left side of the cavity, and as shown by the arrow 26 at the front of the cassette 10. The body 12 of the cassette 10 is completed beyond the defined walls of the cavity 14 by an irregular-formed left side wall 30 and continuing along the rear wall 32 and then along a right side wall 34. A second cavity 36 is formed in the rearward portion of the body 12 by the angled wall 20, the rear wall 32 and a portion of the right side wall 34.

The front part of the cassette 10 is formed of a hollow portion 40 extending across the width of the body 12 and occupying the space from the wall 16 to the front edge 42. The hollow, generally rectangu¬ lar portion 40 is formed to provide a housing or protective cover for a print head or a plurality of individual print solenoids which are connected as a part of the printer. When the cassette 10 is placed or mounted on the printer and the printer is operated,

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the print head or solenoids are caused to be driven in a side-to-side direction under the protective cover of the cassette. A pair of openings 44 are provided and formed in the underside of the housing or cover at the sides thereof for positioning the cassette 10 on the printer. A cover 46, shown in Fig. 2, encloses the cavity 14 and rearward portion of the body 12 of the cassette 10 formed by the walls 16, 30, 32 and 34. A pair of projections 47 at the front of the cover 46 and integral therewith fit into openings 48 in the body 12 for securing the cover thereon.

The internal components of the body 12 of the cassette 10 include a driving member or roller 50 having a lower splined portion 52, as best seen in Fig. 2, for connection to a mating drive member (not shown) on the printer, and an upper toothed gear portion 54. Another internal component of the body 12 is a driven member or roller 56 having an upper toothed gear portion 58 for mating with the gear portion 54 of member 50, and also having a lower grooved or toothed portion 60. The driven member 56 is associated with and drives a ribbon inking member in the form of a roller 64 having a grooved or toothed portion 66 mating with the grooved portion 60 of the driven member 56, as further illustrated in Fig. 3.

The ribbon inking member 64 occupies a portion of the second cavity 36 (Fig. 1) of the body 12. At the left side of the large cavity 14 and being a portion of the body 12 of the cassette 10 is a third cavity 68 (Fig. 1) formed by the wall 18, a small leftward portion of the wall 16, the wall 30 and a small portion of the wall 32 to provide a compartment for twisting the ribbon 22 in mobius-loop manner between a roller 70 journaled on a pin or shaft 72 at the rearward side of the cavity and a roller 74 journaled on a pin or shaft 76 at the cavity forward side. The wall 18 approaches the roller 70 but is short of the rearward

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wall 32 to provide a passageway for the ribbon from the cavity 14 to the cavity 68.

The ribbon 22 is caused to be moved or driven in the direction of the arrows 24 and 26 by means of

5 the roller 50 driving the roller 56 with the ribbon being in contact with the toothed portion 60 thereof and between and in contact with such toothed portion and the toothed portion 66 of the inking roller 64 (Figs. 2, 3 and 4), and then into the cavity or cham-

1° ber 14 (Fig. 1). It is, of course, to be noted that while the ribbon 22 is shown as a single strand within the cavity 14, the ribbon is folded many times in random manner to substantially fill or stuff the cavity, and further that the cavity includes a floor l- ⁵ to support and contain the ribbon.

The ribbon 22 crosses a slightly raised dam portion 80 (Fig. 1) at the left side of the cavity 14, goes through the passageway formed by the end of the wall 18 and a projection on the inside of the wall 32,

²⁰ turns the corner at roller 70, twists 180 degrees between the roller 70 and the roller 74, and then exits from cavity 68 at 82 and moves toward the front edge 42 of the cassette 10. The ribbon 22 moves along the front edge 42 in the direction of the arrow 26 and

" then goes through an entrance at 84 and toward the periphery of the driven roll 56. The front of the cassette 10 includes guide means 86 and 88, as seen in Fig. 2, along with a ribbon guard or shield 90 which is preferably a thin plastic strip secured to the

30 front edge 42. The guide means 86 and 88 are formed to both support and guide the ribbon 22 as it turns the corners at the front of the cassette 10. The ribbon 22, at least in part, is directed along a path behind the guard 90 and may be in contact therewith as

35 it travels past the printing station. The ribbon guard or shield 90 permits the feeding of the ribbon past the printing station without staining the paper.

As illustrated in Figs. 2 and 3, the drive roller 50 is journaled in a cylindrical member or sleeve 100 which may be an integral part of the cas¬ sette body 12, and associated therewith is a support arm 102 which is journaled on the member 100. The support arm 102 has a projection 104 (Fig. 2) extend¬ ing toward the front of the cassette 10 and a coil spring 106 extends between a side surface of the projection and a portion 108 of a short wall 110 (Fig. 1) adjacent the forward wall 16. The spring 106 urges the roller 56 into engagement with the roller 64 by means of a guide portion 112 (Fig. 2) of such support arm 102 being formed to fit partially around and contain the driven roller 56. As illustrated, the guide portion 112 has a two-stage, tongue-and-groove- like construction for bearing and guiding the driven roller 56 (Fig. 3) and, under urgency of the spring 106, rotatably holds the driven roller 56 in position with respect to the inking roller 64 and controls the winding of the ribbon therearound.

The re-inking mechanism of the present invention. includes a removable reservoir or tank 120 of generally triangular shape (Figs. 1 and 2) to fit into the cavity space 36 defined by the angled wall 20, the rearward wall 32 and a rearward portion of the right side wall 34. The reservoir 120 has a cover 122 suitably secured thereto. Further, the reservoir 120 is formed with a cut-out portion 124 in one side to accommodate and fit partially around the inking roller 64 which is journaled on a shaft 126 and which shaft may be an integral part of the cassette body 12, as seen in Fig. 3. The cut-out portion 124 also has a two-stage, tongue-and-groove-like construction for bearing and guiding the inking roller 64, in addition to providing the portions for stripping the ribbon from the inking roller.

The reservoir 120 contains an ink-filled or impregnated porous element 130 (Fig. 3) of low com¬ pression or lesser density material and an ink-filled porous element 132 of high compression or greater density material, the latter element being a generally rectangular portion positioned and contained in a window in a wall of the reservoir adjacent the cut-out portion 124 (see also Fig. 2) . It is recognized that the low density-material element 130 is a primary source of ink for the ribbon 22 by and through trans¬ fer thereof to the high density-material element 132 which provides a continuous and controlled supply of ink to the inking roller 64.

Fig. 4 illustrates the arrangement and operation of the parts in simplified manner wherein the driven roller 56 causes rotation of the inking roller 64 through spring 106 urged engagement of the grooved portion 60 of roller 56 and the grooved por¬ tion 66 of roller 64 with the ribbon 22 therebetween. The element 130 contains a major supply of ink and the element 132 contains a lesser amount of ink with the latter element being in pressure contact with the grooved portion 66 of the inking roller 64, and wherein the ink 134 is contained by surface tension in the grooves of portion 66 and is carried in evenly distributed amount or quantity, as seen on the periph¬ ery of the inking roller 64, from the element 132 to the ribbon 22.

The mechanism of the present invention provides for reinking the ribbon 22 from the local inking element 132 through pressure contact of the inking roller 64 therewith and driving contact of such inking roller with the ribbon 22 prior to moving thereof into the large chamber 14. The effect of the driven roller 56 and ink transfer roller 64 arrange¬ ment is to pull the ribbon 22 from the chamber 14, through the mobius loop section, past the printing

station and back into the body 12 of the cassette 10. The ink 134 is essentially held or contained in the wedge-like grooves in the inking roller 64 and is controlled in a manner so that ink is not supplied to the ribbon 22 in undesirable amounts and/or at unde¬ sirable times. Further, the mechanism of the present invention is constructed to avoid unintentional rever¬ sal of the direction of rotation of the driven roller 56 by reason of the spring 106 urging the support arm 102 and thereby bias such driven roller 56 against the ink transfer roller 64. The arrangement increases the efficiency of the amount of ink being used in the printing operation compared to the supply of ink, and also ensures a steady flow of ink to the ribbon 22. it is thus seen that herein shown and described is a ribbon cassette having a reinking mechanism which utilizes a low density element and a high density element to provide a desired amount and controlled supply of ink, through use of an uneven surfaced inking roller, to the ribbon during operation of the printer. By virtue of this controlled supply of ink, the ribbon is maintained in a properly-inked condition at all times.