GB1604302A - Printer ribbon cartridge and printer - Google Patents

Abstract

An ink-ribbon cartridge (28) in a printer with a moving printing point remains stationary at one place while the ink ribbon (20) moves along a predetermined ribbon length to the printing point and away from the latter. The ribbon length is determined by a first flexible guide element (34) which extends from the cartridge (28) up to the printing point and a second flexible guide element (36) which extends from the printing point back to the cartridge (28). The cartridge (28) bears a supply roll for storing the ink ribbon (20) before it is supplied to the moving printing point and a receiving roll for storing the ink ribbon (20) when it has been returned from the moving printing point. <IMAGE>

Description

(54) PRINTER RIBBON CARTRIDGE AND PRINTER (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to impact printers and, more particularly, to impact printers wherein a ribbon moves between a ribbon storage area and a print point to continuously supply fresh ribbon to a position between a character element and a print receiving medium.

In printers of this type including typewriters, the ribbon storage has been provided by a cartridge. These cartridges are removable so as to permit the ribbon supply to be replenished by merely replacing the ribbon cartridge.

In various printers including typewriters such as those manufactured by IBM and SCM, the platen which supports the print receiving medium in the impact printing position remains stationary and the character printing elements move along the platen to the various printing positions. In these printers the cartridge has been mounted for movement with the character elements and the print point so as to continuously supply fresh ribbon to the print point as the character elements advance. Typically, the cartridge has been supported on a carriage which moves linearly along the platen where the character elements may be mounted on a ball or wheel oftentimes referred to as a daisy.

Where the printer is to operate at high speeds as in the case of a typewriter operating in an automatic memory mode, the carriage must be capable of very high acceleration and deceleration rates which places a substantial demand on the motors, drivers and power supplies for the carriage. Where the carriage also accelerates and decelerates the ribbon cartridge which is mounted on the carriage, the demands on the carriage motor, driver and power supply can become very substantial.

In order to minimize these demands, ribbon cartridges which are mounted on the carriage have had a limited ribbon capacity. Although this has achieved the objective of limiting the weight which must be accelerated and decelerated as the carriage and the print point move, there have been certain, significant penalties.

First, the cartridge must be changed more frequently where the ribbon capacity is small.

This is of course time consuming for the operator of the printer or typewriter and also represents some risk that the print receiving medium may be in some way defaced by removing and replacing the cartridge, e.g., smearing is not at all uncommon in such circumstances. Second, the smaller ribbon cartridges include a rather complex mechanism which is quite costly when one considers that the cartridge is in effect disposable. Where the ribbon capacity is quite limited, the cost of the mechanism relative to the ribbon of the cartridge becomes quite substantial and the overall cost of the cartridge per strike becomes high.

It is an object of this invention to provide a movable print point printer and printing ribbon cartridge for use therein wherein the demands on the printer carriage and associated apparatus are minimized.

It is another object of this invention to provide a movable print point printer wherein the ribbon cartridge may have a substantial capacity without increasing the demands on the movable print point drive.

In accordance with the present invention a printing ribbon cartridge comprises a ribbon storage means for storing a printing ribbon, a flexible supply leader having one end attached to said ribbon storage means and a free end, said supply leader supporting printing ribbon along a path movable relative to said storage means as said free end moves, and a flexible take-up leader having one end attached to said ribbon storage and a free end, said take-up leader supporting printing ribbon along a path movable relative to said storage means as said free end moves.

In a preferred embodiment said printing ribbon cartridge is included in a printer which further comprises means adapted to support a print receiving medium, a laterally movable character printing means juxtaposed to said support means for establishing a laterally movable print point, a printing ribbon stored in said ribbon storage means, said ribbon storage means being stationary, means for advancing said ribbon between said print point and said storage means and past said movable print point in printing relationship with said print receiving medium and said character printing means, means including said flexible supply leader and flexible take-up leader for supporting said ribbon outside said storage means between said storage means and said printing means and for maintaining a substantially constant ribbon path length between said storage means and said print point, the free ends of said flexible supply leader and flexible take-up leader being adapted for coupling to said movable character printing means, said ribbon being exposed in a gap between said free ends, and means for maintaining tension of said ribbon over said ribbon path length including said gap so as to maintain said ribbon path length outside said storage means substantially constant.

In a preferred embodiment, the storage means comprises a supply means for storing ribbon which is fed from said storage means to said print point through one substantially constant ribbon path length and further comprises a take-up means for storing ribbon which is fed from said print point to said take-up means through another substantially constant ribbon path length. The supply means may comprise a supply reel and the take-up means may comprise a take-up reel.

The invention is described with reference to the drawings in which: Figure 1 is a perspective view of a typewriter embodying the invention; Figure 2 is an exploded perspective view of the cartridge and the cartridge holder shown in Figure 1; Figure 3 is a sectional view taken along line 3-3 of the cartridge shown in Figure 1; Figure 4 is a sectional view of the cartridge taken along line 44 of Figure 3; Figure 5 is an enlarged sectional view of the ribbon take-up drive; Figure 6 is a sectional view of the cartridge shown in Figure 3 taken along line 6-6; Figure 7 is an end view of the cartridge showing the ribbon and flexible leaders in the stowed position; Figure 8 is a sectional view of the cartridge shown in Figure 7 taken along line 88;; Figure 9 is a sectional view of a portion of the cartridge shown in Figure 8 taken along line 9-9; Figure 10 is a sectional view of the flexible leader and ribbon of Figure 9 taken along section line 10-10; Figure 11 is a plan view of the typewriter shown in Figure 1 with the print point centrally located with respect to the platen; Figure 12 is a plan view of the typewriter shown in Figure 1 showing the print point at different locations along the platen; and Figure 13 is an enlarged view of a portion of the typewriter shown in Figure 1.

A printer comprising a typewriter shown in Figure 1 includes a keyboard 10 having a multiplicity of keys corresponding to various characters which, upon depression, control the position of a rotatable character array in the form of a print wheel 12 juxtaposed between impact means in the form of a hammer 14 and a platen 16. The platen 16 is adapted to support a print receiving medium in the form of paper 18 which is contacted by the marking medium in the form of an ink ribbon 20 which is located between the print wheel 12 and the paper 18 so as to leave a mark in ink corresponding to the particular character of the print wheel which is in position between the hammer 14 and the paper 18.

As shown in Figure 1, the print wheel 12 and the hammer 14 are mounted on a carriage 22 which is adapted to move in a lateral direction parallel with the surface of the platen 16 so as to position the print wheel 12 at various positions along the paper 18 in response to the depression of keys on the keyboard 10. As the carriage 22 is moved, the print wheel 12 rotates so as to position the proper character element at the end of a radially extending spoke 24 in a printing position aligned with the print hammer 14. The lateral movement of the carriage 22 along the support surfaces 26 may be achieved by various means known in the art including a linear stepper motor such as that shown in US Patent No.4,198,582 of Dan W. Matthias and Richard D. Thornton.

In accordance with this invention, the ribbon 20 is stored within a stationary cartridge 28 which is received, as best shown in Figure 2, by a pocket 30 in an integrally molded receptacle 32. In further accordance with this invention and as shown in Figure 1, the ribbon path length between the print point as determined by the position of the carriage 22 and the cartridge 28 is maintained constant over a substantial portion thereof by a first flexible leader 34 which extends from the cartridge 28 to the carriage 22 and a second flexible leader 36 which extends from the carriage 22 to the cartridge 28.

The leaders 34 and 36 are secured to the cartridge 28 by mounting brackets 38 and 40.

At the carriage 22, the free ends of the leaders 34 and 36 are fastened to carriage posts 42 and 44. The ribbon 20 is then exposed as it spans the gap between the posts 42 and 44 which includes guides 46 and 48. It will be understood that the distance from the post 42 to the print point remains constant as does the distance from the print point to the post 44.

By providing a constant ribbon path length between a stationary cartridge and the movable print point as shown in Figure 1, the ribbon may be continuously advanced as printing proceeds without any necessity for reversing the ribbon as the print point moves in different directions a and b thereby assuring a fresh segment of ribbon for the print point where the segment is guided by the leaders 34 and 36. In this regard, reference is made to Figures 11 and 12 wherein various print point positions relative to the stationary cartridge are shown. In Figure 11, the carriage 22 is substantially centred on the platen and the overall ribbon path length from the cartridge 28 along the leader 34 to the print point at the hammer 14 is substantially equal to the overall path length from the print point along the leader 36 to the cartridge 28.In Figure 12, the carriage 22 as shown in full is moved to the far left of the platen 16 while ribbon path lengths to the print point along the leader 34 and the leader 36 remain equal even though the leaders 34 and 36 have substantially different configurations. When the carriage 22 is advanced in a direction indicated by the arrow b to a position shown in phantom, the overall ribbon path lengths along the leaders 34 and 36 remain the same although the configurations of the leaders 34 and 36 of necessity change.

As clearly shown in Figures 1, 11 and 12, the flexible leaders 34 and 36 do not extend the full ribbon path length to the print point.

Rather, the ribbon 20 is pulled taut between posts 42 and 44 past the print point at the hammer 14 without any support by the leaders 34 and 36. However, since the position of the print point 14 with respect to the posts 42 and 44 remains constant and the overall length of the leaders 34 and 36 remain constant, the overall ribbon path length between the cartridge 28 and the movable print point remain constant.

In order to maintain the overall ribbon path lenth constant, it is important that the flexible leaders 34 and 36 which include loops 52 which are wrapped around the posts 42 and 44 respectively do not rotate on the posts 42 and 44.

Elimination of any rotation as the carriage moves is accomplished by means of keying the loops 50 and 52 to the posts as shown in Figure 13. In this connection, a keying projection 54 at the base of post 42 is received by a notch 56 in the loop 50. A similar keying projection on the post 44 is provided which cooperates with a similar notch on the loop 52. The posts may also be provided with a slight head 58 which serves to hold the flexible leaders down on the posts once the leader is snapped in place.

Reference will now be made to Figures 3-6 for a description of the manner in which the ribbon 20 is stored within the cartridge 28. As best understood with reference to Figure 6, the cartridge 28 comprises a supply reel 60 which is mounted on a common axis 62 with a take-up reel 64. Referring to Figure 3, the ribbon 20 moves from the supply reel 62 through the interior of the cartridge to an outlet 66 at the bracket 38 mounting the leader 34. The tape then moves to the movable print point at the hammer 14 along a fixed path length including the leader 34 and returns to the cartridge 28 along the return fixed path length established in part by the leader 36 which is mounted on the bracket 40 at the inlet 68 of the cartridge 28. From the inlet 68, the ribbon is returned along the path indicated by the arrows to the take-up reel 64.

Drive means is associated with the supply reel 60 so as to meter the ribbon out from supply reel 60 and a take-up drive means is associated with the take-up reel 64 so as to continuously supply a fresh segment of ribbon to the print point. Tension control means associated with the metering drive means and the take-up drive means control the drive of the take-up drive means relative to the metering drive means thereby controlling tension on the ribbon as it passes flexible leaders 34 and 36 so as to control the friction encountered by the ribbon as it moves to and from the movable print point along the fixed path length.

As shown in Figures 3 and 4, the metering drive means compnses a friction drive wheel 70 which is covered with rubber or another suitable material capable of providing sufficient friction so as to pull the ribbon 20 from the supply reel 60. As shown in Figures 4 and 6, the wheel 70 mounted on a shaft 71 is driven through a gear train comprising a gear 72 mounted on the same shaft with the wheel 70 and a gear 74 which engages the gear 72. The gear 74 is driven continuously so as to rotate the wheel 70 as the carriage 22 and the movable print point move.

The take-up drive means as shown in Figures 4 and 5 comprises a wheel 76 which includes a plurality of circumferentially spaced spikes 78.

The wheel 76 is mounted so as to be juxtaposed to the take-up reel 64 and permlt the spikes 78 to penetrate the ribbon 20. In order to provide a tight packing of the ribbon 20 on the take-up reel 64, the spikes 78 have sufficient length to actually penetrate through the first layer of the ribbon 20 and into the second layer of the ribbon 20 on the take-up reel 64. Since the diameter of the outer layer on the take-up reel 64 is greater than the diameter of the interior or second layer on the take-up reel 64, a mechanical advantage is provided which assures that the ribbon may be as tightly packed on the take-up reel 64 as it is originally packed on the supply reel 60.

The take-up drive means provided by the spiked wheel 76 tends to be overdriven with respect to the metering drive means provided by the friction wheel 70. This is accomplished by driving the take-up drive means wheel 76 with a belt which is coupled to the shaft 71 on which the wheel 70 is mounted. As shown in Figure 4, the diameter of the groove 82 in the shaft 71 which is engaged by belt 80 is substantially larger than the groove 84 in the wheel 76 which is engaged by the belt 80. As a consequence, there is a substantial mechanical advantage and the wheel 76 tends to be driven with respect to the tire 70. However, the overdriving condition is limited by slippage between belt 80 and the grooves 82 and 84 of the shaft 71 and the wheel 76. It will therefore be understood that the belt 80 serves in effect, as a clutch, associated with the take-up drive of the wheel 76.

The take-up drive wheel 76 is mounted on an arm 86 which is pivotally attached to a wall 88 of the cartridge 28 at a pin 90. The arm 86 is biased upwardly against the take-up reel 64 regardless of the amount of ribbon stored on the take-up reel by means of the tension on the belt 80. The arm 86 also carries an idler pulley 92 which includes a pair of sideby-side grooves 94 which are engaged by the belt 80. The pulley 92 holds the belt 80 away from the supply reel 60.

As is described in our co-pending application 23095/78 (SErial No 1604301), a dynamic brake is associated with the supply reel 60. As shown in Figure 6, the brake comprises a brake arm 95 which pivots about a point 96. A tension spring 97 at the point 96 biases a braking surface comprising a cellular foam pad 99 against the outermost ribbon on the reel 60 so as to control the tension on the ribbon from the reel 60 to the friction wheel 70 even though the inertia of the supply reel tends to continue rotation of the reel causing slippage between the outer layer of the ribbon in contact with the pad 99 and the inner layer of the reel 60. In order to limit rotation of the reel 60 under these circumstances, a second friction pad 104 is provided in the wall of the cartridge 28 which contacts the edge of the ribbon on the supply reel as shown in Figures 3 and 6.

As shown in Figure 3, the cartridge 28 also includes a number of other idlers and ribbon guides. In the path from the metering drive wheel 72 to the outlet 66, comer pin guides 98 are provided which space the ribbon 20 outwardly away from the arm 86 as well as the accumulated ribbon 20 on the take-up and supply reels 64 and 60. In addition, an idler pulley 100 is provided in this path adjacent the outlet 66 so as to rotate the ribbon 90" for alignment with the bracket mounting 38 and the leader 34.

In the path to the take-up reel 64, a guide pin 102 adjacent the inlet 68 rotates the ribbon 20 90" prior to passage by an idler pulley 104 which maintains the ribbon 20 outwardly spaced from the accumulated ribbon on the take-up and supply reels 64 and 60.

As described and claimed in our co-pending application 23095/78 (Serial No 1604301) the flexible leaders 34 and 36 shown in Figure 10 comprise a steel portion 120 having a radius of curvature transverse to or across the length of the leaders 34 and 36. A cover 122 cooperates with the steel portion 120 so as to form a channel 124 which receives the ribbon 20. The ends 126 of the cover 122 wrap around the edges of the steel portion 120 so as to secure the cover 122 to the steel portion 120. The cross curved steel portion 120 achieves two important functions.

First, the steel portion 120 serves to maintain a curvature in a single direction, i.e., there are no reverse bends or curves in the leaders 34 and 36. It will be understood that this is particularly important in order to prevent the inked surface of the ribbon 20 which is juxtaposed to the plastic member 122 from coming into contact with the plastic member 122.

Second, the cross curved steel portion 120 serves to maintain a substantially constant radius of curvature for the flexible leaders 34 and 36. This allows the flexible leaders 34 and 36 to assume the various positions shown in Figures 11 and 12 without having the flexible leaders extend into a position of interference with the various portions of the printing apparatus. In order for the corss curved steel portion 120 to serve this function, it is necessary that the cover 122 be permitted to slide on the cross curved steel portion 120. By creating this sliding relationship between the cover 122 and the steel portion 120, the steel portion 120 is capable of assuming two beam heights without interference by the cover 122. A first beam height which is shown in Figure 10 is assumed when the leader is substantially straight.A second and lesser beam height is assumed when the leader 34 or 36 has a curvature shown in Figure 11 and 12.

In order to assure that the ribbon 20 remains spaced from the cover 122, the leaders 34 and 36 must maintain a curvature which is concave with respect to the print point. This requires that the steel portion 120 of the leaders 34 and 36 be positioned on the inside of the curvature with the uninked side of the ribbon 20 in contact with the steel portion 120 and facing generally outwardly away from the print point at the print point and the inked side of the ribbon 20 spaced from the cover 122 and facing generally inwardly toward the print point at the print point.

Referring now to Figures 7-9, it will be seen that the leaders 34 and 36 are attached to the cartridge 28 by the brackets 38 and 49 which include projections 140 which are inserted into slots or recesses 142 of the steel portion 120 in the leaders 34 and 36. The plastic cover 122 may then extend up to the bracket 40 or the bracket 38. As shown in Figure 8, the bracket 40 comprises two portions 144 and 146 which tend to sandwich the leader 36 in place with the keying projection 140 properly located with respect to the recesses 142. As also shown in Figure 8, the cartridge 28 includes stowing posts 148 which are adapted to receive the loops 50 when the leaders 34 and 36 are in the stowed position. The posts 148 include heads 150 which retain the loops 50 in place when the leaders 34 and 36 are stowed as shown in Figure 7. Referring again to Figure 2, it will be seen that the cartridge 28 with the leaders 34 and 36 in the stowed position may be inserted into the pocket 30 of the integrally molded receptacle 32. Note further that the receptacle 32 includes integrally molded fingers 160 which are adapted to engage the walls of the cartridge 28. Referring to Figure 3, it will be seen that the fingers 160 are adapted to slide along the walls 162 of the cartridge 28. The bottom of the pocket 30 includes a projection 164 which is received by an opening 166 in the bottom of the cartridge 28 so as to properly locate the cartridge within the receptacle 32.

Although particular flexible leaders are shown and described in connection with the preferred embodiment of the invention, it will be understood that the flexible leaders may take other forms. In fact, the flexible leaders might be eliminated with some other suitable guide means provided for assuring that a fresh segment of ribbon is always juxtaposed to the movable print point and a fixed path length is maintained. Similarly, various modifications may be made in the cartridge itself. For example, the supply reel and the take-up reel may be mounted on separate axes. Or in the alternative, the cartridge may be of the stuffed type without utilizing reels of any kind.

It will therefore be understood that a preferred embodiment of the invention has been shown and described and various modifications may be made which fall within the true spirit and scope of the invention as set forth in the appended claims.

WHAT WE CLAIM IS: 1. A printing ribbon cartridge comprising: ribbon storage means for storing a printing ribbon, a flexible supply leader having one end attached to said ribbon storage means and a free end, said supply leader supporting printing ribbon along a path movable relative to said storage means as said free end moves, and a flexible take-up leader having one end attached to said ribbon storage and a free end, said takeup leader supporting printing ribbon along a path movable relative to said storage means as said free end moves.

2. A printing ribbon cartridge according to Claim 1 wherein said ribbon is exposed between said free end of said supply leader and said free end of said take-up leader.

3. A printing ribbon cartridge according to Claim 2 wherein said ribbon storage means comprises a first reel for storing ribbon prior to use and take-up means for storing ribbon after use.

4. A printing ribbon cartridge according to Claim 3 wherein said take-up means includes means for maintaining tension in the portion of said ribbon outside said ribbon storage means.

5. A printing ribbon cartridge according to Claim 4 wherein said supply leader and said means for maintaining tension are cooperatively related to maintain a substantially constant ribbon path length outside said storage means.

6. A printer which includes a printing ribbon cartridge according to any of the prece

Claims (1)

1. ding claims.

   7. A printer which includes a printing ribbon cartridge according to Claim 1 further comprising means adapted to support a print receiving medium, a laterally movable character printing means juxtaposed to said support means for establishing a laterally movable print point, a printing ribbon stored in said ribbon storage means, said ribbon storage means being stationary, means for advancing said ribbon between said print point and said storage means and past said movable print point in printing relationship with said print receiving medium and said character printing means, means including said flexible supply leader and flexible take-up leader for supporting said ribbon outside said storage means between said storage means and said printing means and for maintaining a substantially constant ribbon path length between said storage means and said print point, the free ends of said flexible supply leader and flexible take-up leader being adapted for coupling to said movable character printing means, said ribbon being exposed in a gap between said free ends, and means for maintaining tension of said ribbon over said ribbon path length including said gap to as to maintain said ribbon path length outside said storage means substantially constant.

   8. A printer according to Claim 7 wherein said means for maintaining tension comprises take-up means for said ribbon, said take-up means taking up any slack in said ribbon as said print point moves.

   9. A printer according to Claim 8 wherein said take-up means is included in said ribbon storage means.

   10. A printer according to Claim 7 wherein said flexible leader portions extend over a substantial portion of said path length and said print point is located within said gap between said free ends.

   11. A printer according to Claim 9 further comprising supply means for said ribbon, said supply means taking up any slack in said ribbon as said print point moves.

   12. A printer according to Claim 7 wherein said storage means comprises a supply means for storing ribbon which is fed from said storage means to said print point through one substantially constant ribbon path length and further comprises a take-up means for storing ribbon which is fed from said print point to said take-up means through another substantially constant ribbon path length.

   13. A printer according to Claim 12 wherein said supply means comprises a supply reel and said take-up means comprises a take-up reel.

   14. A printer according to Claim 13 further comprising a removable cartridge comprising said supply reel and said take-up reel.

   15. A printing ribbon cartridge according to Claim 1 substantially as hereinbefore described with reference to the drawings.