CA1155077A - Printer with movable print point and stationary marking ribbon storage - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The invention relates to a ribbon cartridge for use in a printing machine which machine has a stationary receiver for receiving the cartridge and a printing carriage movable with respect to the receiver along a printing path. The printing carriage includes a printer.
The cartridge includes a ribbon supply means for storing a supply of ribbon and a casing for the ribbon supplying means which is supportable by the stationary receiver. A
ribbon guide is connected to the casing and is connectable to the printing carriage to guide the ribbon from the ribbon supply means to the printing carriage and then back.
The ribbon guide includes a flexible member for guiding ribbons from the ribbon supply means to the printing carriage along a path of substantially unvarying length irrespective of the position of the printing carriage along the printing path and then back to the ribbon supply means.

Description

- :liS50~7 This application is a division of Application Ser. No. 310,366, filed August 30, 1978.
Thi8 invention relates to impact printers and, more particularly, to impact printers wherein a ribbon moves between a ribbon storage ares 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 80 as to continuously supply fresh ribbon to the print point as the character elements advance. Typically, the cartridge ha6 been supported on a carriage which moves linearly along thç platen where the character elements may be mounted on a bal~ or wheel oftentimes referred to as a daisy. Where the printer is to operate at high speeds as ~n 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, driver~ 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 mlnimize these demands, ribbon car-

- 2 -: liSS077 1 tridges which are mounted on the carriage have had a 2 limited ribbon capacity. Although this has achieved the

3 ob3ective of limiting the weight which must be accelerated and decelersted as the carriage and the print point move, there have been certain, significant penalties. First, 6 the cartridge must be changed more frequently where the 7 ribbon capacity is small. This is of course time-consuming 8 for the operator of the printer or typewriter and also 9 ~epresents some risk that the print receiving medium may be in some way defaced by removing and replacing the 11 cartridge, e.g., smearing is not at all uncommon-in suc~-12 circumstances, Second, the smaller ribbon cartridges include 13 a rather complex mechanism which is quite costly when one 14 considers that the cartridge is in effect disposable. Where the ribbon capacity is quite limited, the cost of the 16 mechanism relative to the ribbon of the cartidge becomes 17 quite substantial and the overall cost of the cartridge 18 per strike becomes high.

~ It is an ob~ect of this invention to provide a 21 movable print point printer wherein the demands on the 22 printer carriage and associated apparatus are minimized.
23 It is another object of this invention to provide 24 a movable print point printer wherein the ribbon cartridge may have a substantial capacity without increasing the 26 demands on the movable print point drive.
27 It is a further ob~ect of this invention to pro-28 vide a movable print point printer wherein the cost of the 29 printer as well as the cost per character strike is minim~d In accordance with these and other ob~ects, the 31 preferred embodiment of the invention comprises a printer 32 adapted to support a print receiving medium and a laterally movable character printing means juxtaposed to the support means for establishing a laterally movable print point. A
ribbon carrying a printing medium advances past the movable print point in printing relationship with the print receiving medium and the character printing means is stored within a stationary ribbon storage means. The means maintain a sub-stantially constant ribbon path length from the stationary ribbon storage means to the movable print point.
-The means for maintaining the substantially constant ribbon path length may comprise a flexible leader for supporting the ribbon through the path lengthO Preferably, two such flexible leaders are provided with one flexible leader extending from the ribbon storage means to the print point and another flexible leader extending from the print point to the storage means.
The storage means of the preferred embodiment comprises a supply means for storing ribbon which is fed from the storage means to the print point through one flexible leader and further comprises a take-up means for storing the ribbon which is fed from the print point to the take-up means through the other flexible leader. Preferably, the supply means comprises a supply reel and the take-up means comprises a take-up reel which are mounted in a removable cartridge.
In accordance with a specific embodiment of the invention there is provided a ribbon cartridge for use in a printing machine which machine has stationary means for receiving said cartridge, and a printing carriage movable with respect to the stationary means along a printing path.
The printing carriage comprises printing means. The cart-ridge includes ribbon supply means for storing a supply ofribbon and a casing for the ribbon supply means including ~1550~77 means to enable the casing to be supported by the stationary means. Ribbon guiding means are connected to the casing and inclucle means for connection to the printing carriage to guide the ribbon from the ribbon supply means to the print-ing carriage and then back. The ribbon guiding means includes flexible means for guiding ribbon from the ribbon supply means to the printing carriage along a path of substantially un-varying length irrespective-of the position of the printing carriage along the printing path and then back to the ribbon supply means.
In accordance with a further embodiment of the invention there is provided a printing ribbon cartridge which comprises ribbon storage means for storing said printing ribbon;
a flexible supply leader having one end attached to said ribbon storage means and a free end, said 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 leader supporting printing ribbon along a path movable relative to said storage means as said free end moves.
In accordance with a still further embodiment of the invention there is provided a printer which 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, the improvement comprising: a ribbon comprising a printing medium, stationary ribbon storage means for storing said ribbon: means for advancing said ribbon so as to continuously supply a segment of fresh ribbon to said print point; and means for guiding said segment to said print point as said print point moves.

- 4a -11~50~7 BRIEF D~:SCRIPTIO~ OF THE DRAWI~GS
Fig. 1 is a perspective view of a typewriter embodying the invention, Fig. 2 is an exploded perspective view of the cartridge and the cartridge holder shown in Fig. 1;
Fig. 3 is a sectional view taken along line 3-3 of the cartridge shown in Fig. l;
Fig. 4 is a sectional view of the cartridge taken - 4b -llS5077 along line 4-4 of Fig, 3, Fig. 5 is an enlarged sectional view of the ribbon take-up drive, Fig, 6, which is on the same sheet of drawings as Fig, 2, is a sectional view of the cartridge shown in Fig, 3 taken along line 6-6, Fig, 7 is an end view of the cartridge showing the ribbon and flexible leaders in the stowed position;
Fig, 8 is a sectional view of the cartridge shown in Fig, 7 taken along line 8-8, Fig, 9 is a sectional view of a portion of the cartridge shown in Fig, 8 taken along line 9-9, Fig, 10 is a sectional view of the flexible leader and ribbon of Fig, 9 taken along section line 10-10 Fig. 11 is a plan view of the typewriter shown in Fig. 1 with the print point centrally located with respect to the platen;
Fig. 12 is a plan view of the typewriter shown in Fig. 1 showing the print point at different locations along the platen; and Fig. 13, which is on the same sheet of drawings as Fig. 1, is an enlarged view of a portion of the typewriter shown in Fig. 1.
DETAILED DESCRIPTIO~ OF A PREFERRED EMBODIMENT
A printer comprising a typewriter shown in Fig. 1 includes a keyboard 10 having a multiplicity of keys corres-ponding 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 sup-port 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 llS5~77 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 Fig. 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 key-board 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 Canadian application Ser. No.
303,582, filed May 17, 1978 assigned to the assignee of this invention.
In accordance with this invention, the ribbon 20 is stored within a stationary cartridge 28 which is received, as best shown in Fig. 2, by a pocket 30 in an integrally molded receptacle 32. In further accordance with this invention and as shown in Fig. 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 : 11550~7 1 posts 42 and 44. The ribbon 20 is then exposed as it 2 spans the gap between the posts 42 and 44 which includes 3 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.
6 By providing a constant ribbon path length be-7 tween a stationary cartridge and the movable print point as 8 shown in Fig. l, the ribbon may be continuously advanced 9 as printing proceeds without any necessity for reversing the lo ribbo~ as the print point moves in different directions 11 a and b thereby assuring a fresh segment of ribbon for the 12 print point where the segment is guided by the leaders 13 34 and 36. In this regard, reference is made to Figs. ll 14 ~and 12 wherein various print point positions relative to the stationary cartridge are shown. In Fig. l~, the carriage 16 22 is substantially centered on the platen and the overall 17 ribbon path length from the cartridge 28 along the leader 18 34 to the print point at the hammer 14 is substantially 19 equal to the overall path length from the print point along ~ the leader 36 to the cartridge 28. In Fig. 12, the car-21 riage 22 a6 shown in full is moved to the far left of the 22 platen 16 while ribbon path lengths to the print point 23 along the leader 34 and the leader 36 remain equal even 24 though the leaders 34 and 36 have substantially different 2s configurations. When the carriage 22 is advan~ed in a 26 direction indicated by the arrow b to 8 position shown in phantom, the overall ribbon path lengths along the leader8 34 and 36 remain the same although the configurations of the leaders 34 and 36 of necessity change.
AB clearly shown in Figs. l, ll and 12, the flexi-31 ble leaders 34 and 36 do not extend the full ribbon path 32 le~gth to the print point. Rather, the ribbon 20 is pulled llSS077 ~ taut between posts 42 and 44 past the print point at the 2 hammer 14 without any support by the leaders 34 and 36.
3 However, si~ce the position of the print point 14 with re-

4 $pect to the posts 42 and 44 remains constant and the over-811 length of the leaders 34 and 36 remain constant, the ~ overall ribbon path length between the cartridge 28 and 7 the movsble print point remain constant.
8 In order to maintain the overall ribbon pat~
9 length constant, it is important that the flexible leaders 34 and 36 which include loops 52 which are wrapped around 11 the posts 4~ and 44 respectively do not rotate on the 12 posts 42 and 44. Elimination of any rotation as thç
13 carriage moves is accomplished by means of keying the loops 14 50 and 52 to the posts as shown in Fig. 13. In this con-nection, a keying pro~ection 54 at the base of po~t 42 is 16 ~eceived by a notch 56 in the loop 50. A similar keying 17 projection on the post 44 is provided which cooperate8 18 with a similar notch on the loop 52. The posts may also be 19 provided wlth a slight head 58 which serves to hold the ~ flexible leaders down on the posts once the leader is snap-21 ped in place.
22 Reference wlll now be made to Figs. 3-6 for a 23 description of the manner in which the ribbon 20 is stored 24 within the cartridge 28. As best under~tood with reference ~5 to Fi8. 6, the cartridge 28 comprises a supply reel 60 which 26 is mounted on a common axi~ 62 with a take-up reel 64.
Referring to Fig. 3, the ribbon 20 move~ 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 31 fixed path length including the leader 34 and returns to 32 the cartridge 28 along the return fixed path length estab-115S~)77 lished 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 Figs. 3 and 4, the metering drive means comprises a friction drive wheel 70 which is covered with rubber or another suitable material capable of providing sufficient friction æo as to pull the ribbon 20 from the supply reel 60. As shown in Figs. 4 and 6, the wheel 70 mounted on a shaft 71 is driven through a gear train compris-ing 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 Figs. 4 and 5 comprises a wheel 76 which includes a plurality of circum-ferentially spaced spikes 78. The wheel 76 is mounted so as to be juxtaposed to the take-up reel 64 and permit 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 _ g _ 11550~7 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. m is 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 Fig. 4, the diameter of the groove 82 in the shaft 71 which is engaged by belt 80 is substan-tially larger than the groove 84 in the wheel 76 which is engaged by the belt 80. As a consequence, there is a sub-stantial 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 regardle~s of the amount of ribbon ~tored on the take-up reel by means of the tension on the belt 80.
Ihe arm 86 also carries an idler pulley 92 which includes a pair of side-by-side grooves 94 which are engaged by the llS5V~7 belt 80. m e pulley 92 holds the belt 80 away from the supply reel 60.
In accordance with the invention of Canadian appli-cation Ser. No. 310,365 filed August 30, 1978, which is assigned to the assignee of this invention, a dynamic brake is associ-ated with the supply reel 60. As shown in Fig. 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 circum-stances, 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 Figs. 3 and 6.
As shown in Fig. 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, corner 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.
In accordance with the invention of the afore-said Canadian application Ser. ~o. 310,365, which is assigned to the assignee of this invention, the flexible leaders 34 and 36 shown in Fig. 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 12Z 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 under-stood 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 xadius of curvature for the flexible leaders 34 and 36. This allows the flexible leaders 34 and 36 to assume the various positions shown in Figs. 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 cross curved steel portion 120 to serve this function, it is necessary that the cover 122 be permitted to slide on the cross curved steel 1 portion 120. By creating this sliding relationship between 2 the cover 122 and the steel portion 120, the steel portion 3 120 is capable of assuming two beam heights without inter-4 ference by the cover 122. A first beam height which is shown in Fig. 10 is assumed when the leader is substantially 6 straight. A second and lesser beam height is assumed when 7 the leader 34 or 36 has a curvature shown in Fig. 11 and 8 12.
9 In order to assure that the ribbon 20 remains spaced from the cover 122, the leaders 34 and 36 must main-11 tsin a curvature which is concave with respect to the print 12 point. This requires that the steel portion 120 of the 13 leaders 34 and 36 be positioned on the inside of the curya-14 ture wi~h the uninked side of the ribbon 20 in contact with the steel portion 120 and facing generally outwardly away 16 from the print point at the print point and the inked side 17 of the ribbon 20 spaced from the cover 122 and facing gener-18 ally inwardly toward the print point at the print point.
19 Referring now to Figs. 7-9, it will be seen that the leaders 34 and 36 are attached to the cartridge 28 by 21 the brackets 38 and 40 whlch include pro3ections 140 which 22 are inserted into slots or recesses 142 of the steel portion 23 120 in the leaders 34 and 36. The plastic cover 122 may 24 then extend up to the bracket 40 or the bracket 38. As shown in Fig. 8, the bracket 40 comprises two portions 144 ~6 and 146 which tend to sandwich the leader 36 in place with D the keying projection 140 properly located with respect to 28 the recesses 142. As also shown in Fig. 8, the cartridge ~ 28 includes stowing posts 148 which are adapted to receive the loops 50 when the leaders 34 and 36 sre in the stowed 31 position. The posts 148 incl~de heads 150 wh~ch retain the 32 loops 50 ln place when the leaders 34 and 36 are Rtowed a8 llSS~)77 l shown in Fig. 7.
2 Referring again to Fig. 2, it will be seen that 3 t~e cartridge 28 with the leaders 34 and 36 in the s owed 4 position may be inserted into the pocket 30 of the integ-rally molded receptacle 32. Note further that the recep-6 tacle 32 includes integrally molded fingers 160 which are 7 adapted to engage the walls of the cartridge 28. Referring 8 t~ Fig. -3, it will be seen that the fingers 160 are adapted 9 to slide along the walls 162 of the cartridge 28. The bottom of the pocket 30 includes a projection 164 which ll is received by an opening 166 in the bottom of the cartridge l~ 28 so as to properly locate the cartridge within the re-1~ ceptacle 32.
14 Although particular flexible leaders are shown and ~escribed in connection with the preferred embodiment 16 of ~he invention, it will be understood that the fle~ible l7 leaders may take other forms. In fact, the flexible leaders l8 might be eliminated with some other suitable guide means l9 provided for assuring that a fresh segment of ribbon is always 3uxtaposed to the movable print point and a fixed ~l path length is maintained. Similarly, various modifica-22 tions may be made in the cartridge itself. For example, 23 the supply reel and the take-up reel may be mounted on 24 separate axes. Or in the alternative, the cartridge may be of the stuffed type without utilizing reels of any kind.
26 It will therefore be understood that a preferred D embodiment of the invention has been shown and described and various modifications may be made wh~ch fall within 29 the true spirit and scope of the invention as set forth in the appended cla~ms.

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A ribbon cartridge for use in a printing machine which machine has stationary means for receiving said cartridge, and a printing carriage movable with respect to said stationary means along a printing path, said printing carriage comprising printing means, said cartridge comprising:
ribbon supply means for storing a supply of ribbon, a casing for said ribbon supply means including means to enable the casing to be supported by said stationary means, and ribbon guiding means connected to said casing and including means for connection to said printing carriage to guide the ribbon from said ribbon supply means to said printing carriage and then back, said ribbon guiding means including flexible means for guiding ribbon from said ribbon supply means to said print-ing carriage along a path of substantially unvarying length irrespective of the position of the printing carriage along said printing path and then back to said ribbon supply means.

2. A ribbon cartridge according to claim 1 and further comprising:
ribbon take-up receiving means for storing used ribbon, said ribbon take-up receiving means having a ribbon input, said ribbon supply means having a ribbon output, said casing for said ribbon supply means further enclosing said ribbon take-up receiving means, and said ribbon guiding means including means for guiding the ribbon from said output of said ribbon supply means to said printing carriage along a path of substantially unvarying length irrespective of the position of said printing carriage along the printing path and then guiding the ribbon from said printing carriage back to said ribbon input.

3. A ribbon cartridge according to claim 2 wherein said ribbon-guiding-means is flexible.

4. A ribbon cartridge according to claim 3, said flexible ribbon-guiding-means is attached to said casing and connectable to said printing apparatus for guiding the ribbon from said output to the printing apparatus and then back to said input along a path of unvarying length irres-pective of the position of the printing apparatus along said writing line.

5. A ribbon cartridge according to claim 4 wherein said flexible ribbon-guiding-means comprises a non-articulated closed loop for connecting to said printing apparatus to guide the ribbon from said output of said printing apparatus and then back to a position adjacent said output along a path of unvarying length irrespective of the position of the printing apparatus along said writing line.

6. A ribbon cartridge as defined in claim 5 wherein said flexible ribbon guiding means is constrained by said attachment to said casing to form a compliant closed loop structure, said guiding means having a ribbon guiding surface outwardly disposed of said loop structure for guiding the ribbon therealong, and said loop structure being connectable, at a point midway therearound from said attachment, to said printing apparatus to provide said path of unvarying length.

7. A ribbon cartridge according to claim 1 wherein said ribbon guiding means comprises a flexible supply leader having one end attached to said casing and a free end, said leader supporting printing ribbon along a path movable relative to said casing as said free end moves; and a flexible take-up leader having one end attached to said casing and a free end, said leader supporting printing ribbon along a path movable relative to said casing as said free end moves.

8. The ribbon cartridge of claim 7 wherein said ribbon is exposed between said free end of said supply leader and said free end of said take-up leader.