EP0128867A2 - Sheet-feeding apparatus for a printer or a typewriter - Google Patents

Abstract

The sheet feeding device (1) comprises several cassettes (13) on which the sheets (11) are stacked, an extraction mechanism, associated with each of the supports, intended to extract a sheet from the cassette (13) and to introduce it into the printer (2), and a selection mechanism (55) intended to activate one of the extraction mechanisms. The extraction and selection mechanisms (55) are driven by the striking cylinder (3) of the printer (2). The selection mechanism (55) uses the position occupied by the mobile carriage (4). The latter carries an actuating part (61) capable of cooperating with a set of selection levers (56). These levers (56) are equal in number to the extraction mechanism. Depending on the position occupied by the carriage during selection, one or other of the levers (56) is put into the active position and moved by a drive wheel (65) to actuate an extraction control member ( 76) and to initiate the extraction and introduction process. This device has the advantage that the striking cylinder (3) is driven only in one direction during the complete cycle of selection, extraction and introduction of a sheet into the printer.

Description

The present invention relates to a sheet feeding device for printer or typewriter with a movable carriage comprising a frame, one or more supports on which the sheets to be printed are stacked, an extraction mechanism, associated with each of the supports, intended extracting a sheet of the support for introduction into the printer, and a selection mechanism for activating one of the extraction mechanisms.

This construction method is already known from the German patent DE 2,950,707. The device described in this patent comprises a selection mechanism driven by the striking cylinder making it possible to activate one of the paper extraction mechanisms driving the striking cylinder first over a predetermined distance in a first direction opposite to the introduction of the paper, reversing the direction of drive over a small predetermined distance, then driving the cylinder again in the first direction to advance the sheet to the striking cylinder and reversing the direction of a third time Striking cylinder drive to feed paper into the printer. To perform a cycle of feeding a sheet into the printer, the device requires multiple reversals of the direction of rotation of the drive of the device, which makes the drive control complicated. In addition, when a sheet inserted in the printer is partially printed and the operator wishes to complete or correct a line previously written, the device described in this German patent allows to go back only a few lines, otherwise the one of the extraction mechanisms is driven to advance a sheet towards the printer, which can disturb the operation of the device.

The present invention aims to create a device performing a selection cycle of extraction and introduction of paper which does not require any reversal of the driving direction of the striking cylinder. The device is characterized, for this purpose, in that the selection mechanism comprises. a feeler device capable of cooperating with the mobile carriage, in order to determining the position occupied by the latter, this feeler device comprising at least one actuating member intended to activate, as a function of the position occupied by the carriage, one of said extraction mechanisms. According to the invention, the selection criterion for the extraction mechanism therefore consists of the position occupied by the mobile carriage during the selection phase.

• La figure 1 est une vue latérale en coupe représentant l'ensemble du dispositif monté sur une imprimante.
• La figure 2 est une vue latérale illustrant des particularités du dispositif.
• La figure 3 est une vue de dessus selon C-C de la figure 2.

The accompanying drawing shows, by way of example, an embodiment of the device which is the subject of the invention.

• Figure 1 is a side sectional view showing the entire device mounted on a printer.
• Figure 2 is a side view illustrating features of the device.
• FIG. 3 is a top view along CC of FIG. 2.

With reference to FIG. 1, the sheet feeder 1 is mounted on a printer 2 or typewriter comprising a striking cylinder 3 and a movable carriage 4 movable along the cylinder and carrying a writing device 5, such as a needle head or a character disc. A drive shaft 6 connected to a drive motor preferably of the stepping type, not illustrated, drives the cylinder 3. Back pressure rollers, of which only one 7 is shown, are elastically biased against the cylinder and constitute a drive mechanism 25 for advancing in a known manner a sheet of paper introduced into the printer.

The supply device 1 comprises a chassis 40, the side walls 41 of which have notches 42 which fit on the shaft 43 of the striking cylinder 3. The base 44 of the chassis rests on the rear part of the printer 2. The feeding device 1 comprises supports 8 and 9 on which the sheets II to be printed are stored. These supports include cassettes 12 and 13, which can be placed on retaining plates 14, 15 and be removed from these locations. Cassettes 12, 13, rectangular in shape laire, have a bottom 16 and side walls 17, 17a. The latter have at their upper part retaining members 18, 18a, in the form of flanges intended to retain the sheets 11 placed on a support plate 19. This plate 19 is biased in its lower part by a spring 20 in the direction of the members retainer 18. At its upper part, the plate 19 is maintained substantially in contact with the bottom 16. A more detailed description of these cassettes is presented in Swiss Patent No.

An extraction mechanism 21, 22, is associated with each of the supports 8, 9 and serves to shift and extract the tallest sheet from the stack of sheets 11 and to transport it through a channel 23, 24 to a paper driving device 25. As described in detail below, this mechanism is arranged so as to transport the sheet upwards using a roller 26. The lower edge of the sheet then emerges from the members retainer 18 and the sheet, abutting against the upper wall 17a of the cassette, forms a pocket 10. The roller 26 then drives the sheet in the opposite direction. The lower edge passes over the retaining members 18 and the pocket 10 is eliminated. The roller 26 is then released from the sheet which falls in free fall on an alignment stop 27. A transport device 28, constituted by two rollers 29, 30, is then made active to introduce the sheet in a controlled manner into the printer 2 where it is taken up by the drive device 25.

The device 1 further comprises two supports 31 and 32 intended for the storage of the printed sheets. After printing, the latter pass through the outlet channel 33, where they are driven by the transport device 34 also consisting of two drive rollers 35 and 36 to be deposited in normal order on the support 31 or in reverse sequence on the support 32. The wall 45 separating the two supports is pivotally mounted for this purpose around a pivot 46. A lever 48 makes it possible to block this wall 45 in a given position. The lower edge 47 of the wall 45 has two guide surfaces leading the sheets to the outlet of the channel 33 either to the left on the support 31 or to the right on the support 32.

The support 32 can also be used as a support for feeding envelopes or sheets to be printed. It has, for this purpose, in its lower part, a channel 49 adapted so as to drive the envelopes towards the cylinder 3. An extraction mechanism 50 is arranged at the lower part of the support 32 and makes it possible to offset and to drive the lowest envelope of a stack placed on the support 32. The stack of envelopes is held by rollers 51 arranged on a transverse bar fixed to the end of an angled lever 52 mounted pivoting around a pivot 53. The rollers 51 are. biased by a spring 54 towards the rear wall of the support 32. If this support is used as a reservoir for the sheets already printed, the rollers 51 rest on this wall so as to obstruct the entry of the channel 49.

With reference to FIGS. 2 and 3, the feed device comprises a selection mechanism 55 intended to activate, according to the user's choice, one of the extraction mechanisms 21, 22, 50. This selection mechanism 55 comprises a feeler device constituted by a set of levers comprising a number of selection levers 56 equal to the number of extraction mechanisms 21, 22, 50. Each of the levers 56 has an opening 57 in which is engaged a fixed shaft 38. Each of the selection levers 56 is, therefore, capable of pivoting around the shaft 58 and of being displaced longitudinally along the opening 57. A plate 60 secured to the chassis 40 has slots to guide the levers 56. The latter are urged by a spring 59 in a rest position and comprise a pawl 63 pivotally mounted on the lever 56. The pawls 63 have a tooth 64 capable of cooperating with a toothed drive wheel 65 and they are biased by a spring 69 con be a stop 70 carried by the levers 56. The mechanism comprises a toothed wheel 65, driven by the striking cylinder 3 by means of gears 66 to 68 so as to rotate in the opposite direction to the striking cylinder 3.

An actuating part 61 is rigidly fixed on the carriage 4 and has a rounded upper part 62 capable of cooperating with only one of the levers 56 at a time so as to pivot the latter around the shaft 58 from an inactive position towards an active position in which the tooth 64 engages in the teeth of the toothed wheel 65 to be moved to the right in FIG. 2.

The supply device comprises, associated with each of the levers 56, an extraction control part, such as the rockers 76 to 78. These rockers are pivotally mounted on a shaft 95 and biased by a spring 80 against a rest stop. 81. They cooperate with one of their ends 79 with the corresponding actuation lever 56. A rotation of one of the flip-flops 76 to 78 anticlockwise causes the corresponding extraction mechanism to start.

Each of the extraction mechanisms associated with the paper supports comprises a cam 90 to 92. This cam is pivotally mounted around an eccentric pivot 93 disposed at one of the ends 94c of a bent arm 94 capable of pivoting around the 'shaft 95. A stop 96 integral with the cam 90 cooperates with the end 97 of the rocker 76 to prevent the cam 90 from rotating around the pivot 93. A spring 102 biases the bent arm 94 against a fixed stop 101 so that the periphery of the cam 90 occupies a position close to the periphery of a toothed wheel 89, but does not touch this periphery, when the end 97 is in contact with the stop 96. Each of the extraction mechanisms further comprises a lever 98 pivotally mounted around the shaft 95. This lever 98 is biased by a spring 99, arranged between the lever 98 and a projecting portion 94a of the bent arm 94, against a part 100 integral with the cam 90 of so as to rotate the cam 90, when the ex end 97 is released from stop 96.

The periphery of the cam 90 comprises a first portion 90a constituted by a toothing capable of cooperating with the toothed wheel 89 driven by the wheel 65 and a second smooth portion 90b capable of sliding on this toothed wheel 89 under the action of the spring 102.

The other end 94b of the bent arm 94 is coupled to a pull rod 105 controlling means 106 for separating a sheet and putting it in place. place of the alignment stop 27. This alignment stop is constituted by a comb-shaped part fixed between two arms 107 pivoting around a shaft 108 fixed to the chassis. A finger 125 secured to the pull tab 105 is connected by a spring 109 to one of the arms 107.

The separation means 106 comprise, near the two side walls 41 of the chassis 40, a lever 110 mounted on a shaft 111 fixed to the chassis and a bracket 112 also pivoting around the shaft III. The lever 110 and the bracket 112 are connected by a spring 113 urging the bracket 112 towards a rest position determined by two stops 114 and 115 carried by the lever 110 respectively the bracket 112. The roller 30 of the extraction mechanism is pivotally mounted on a shaft 116 held by the levers 110. A spring 117 biases the levers 110 in a position such that the roller 30 remains in contact with the roller 29 fixed on a shaft 118 mounted on bearings integral with the chassis. This shaft 118 is driven by the striking cylinder 3 by means of gears 66, 67, 119, so that the roller 29 and the striking cylinder 3 rotate in opposite directions.

The roller 26 comprises a shaft 122 mounted on the brackets 112. A toothed wheel 123 secured to the shaft 122 cooperates with a toothing 124 in the form of a segment of a circle carried by one end of one of the levers 110. The other end of this lever 110 is arranged so as to cooperate with the finger 125 integral with the pull tab 105 to control a pivoting of the lever 110 around the shaft 111. The device further comprises a stop 126 intended to fix the exact position of the stop d alignment 27 during its installation and stops 127 to limit the pivoting of the bracket 112 around the shaft 111.

The rollers 26, 29 and 30 are covered with elastomer to ensure a friction drive of the sheets of paper. The sheet feeding device can be adapted to any printer in a typewriter comprising a control unit 130 capable of precisely controlling the drive of the striking cylinder.

It is obvious that the set of levers 56 must be arranged facing a portion of the striking cylinder not used for printing. These levers 56 are, therefore, advantageously mounted opposite the right end of the striking cylinder outside the usual writing area in a so-called selection area.

The device operates as follows. When the control unit 130 of the printer receives the order to introduce a given type of sheets stacked on the supports 8, 9 and 32, it controls the movement of the carriage in the selection area so that the piece 61 rotates one of the levers 56 around the shaft 58 in the active position. The tooth 64 of the pawl 63 then cooperates with the toothed wheel 65. The striking cylinder 3 is at this moment driven in the direction of introduction of the paper. The lever 56 is pushed to the right in FIG. 2, it actuates the rocker 76 which emerges from the stop 96.

• - Mise en place de la butée d'alignement 27.
• - Pivotement du levier 110 et de l'équerre 112 autour de l'arbre 111, jusqu'à ce que l'équerre 112 vienne en contact avec la butée 127.
• - Le levier 110 continue son mouvement de pivotement et entraîne grâce à l'engrenage 123, 124, le rouleau 26 dans un sens senestre; en contact avec la feuille la plus haute contenue dans la cassette 13, ce rouleau déplace cette feuille par friction sur une distance de un centimètre environ vers le haut pour dégager le bord inférieur de la feuille sous les organes de retenue 18 de la cassette 13, et pour former la poche 10 (voir figure 1).

By pressing on the part 100, the arm 98, biased by the spring 99, drives the cam 90 in rotation, which due to its eccentricity comes into contact with the toothed wheel 89. The latter is driven in the same direction as the cylinder 3 and strikes the cam 90 in rotation. The pull tab 105 is then first moved to the left in FIG. 2 and successively controls the following operations:

• - Installation of the alignment stop 27.
• - Pivoting the lever 110 and the bracket 112 around the shaft 111, until the bracket 112 comes into contact with the stop 127.
• - The lever 110 continues its pivoting movement and drives, thanks to the gear 123, 124, the roller 26 in a semester direction; in contact with the uppermost sheet contained in the cassette 13, this roller displaces this sheet by friction over a distance of about one centimeter upward to release the lower edge of the sheet under the retaining members 18 of the cassette 13, and to form the pocket 10 (see Figure 1).

• - Le levier 110 pivote dans le sens contraire, entraînant le rouleau 26 dans un sens dextre, ce dernier transporte ta feuille de papier par dessus les organes 18 vers le bas.
• - Lorsque la poche est entièrement résorbée et la feuille posée à plat, le rouleau 26 se dégage de la feuille qui tombe en chute libre sur la butée d'alignement 27.
• - L'unité de commande 130 commande à ce moment un arrêt du moteur d'entraînement d'une durée de une seconde environ pour assurer que cette chute s'effectue sans entrave.
• - Après cette chute et la mise en marche du moteur d'entraînement, la périphérie lisse 90b entre en contact avec la roue 89 et glisse sur cette dernière.
• - L'unité 130 commande un nouvel arrêt du moteur d'entraînement. Pendant cet arrêt, le levier 110, sollicité par le ressort 117 continue à pivoter pour permettre la fermeture des deux rouleaux d'entraînement 29 et 30. La tirette 105 commande ensuite l'escamotage de la butée d'alignement 27 sous l'effet de la traction du ressort 102 agissant sur le bras 94. La périphérie 90a munie de la denture entre alors de nouveau en contact avec la roue dentée 89.
• - Le moteur d'entraînement est mis en marche pendant une durée qui est fonction de la longueur d'introduction désirée du papier et commandée par l'unité 130. Pendant cette opération, la came 90 est entraînée par la roue 89 et le bras coudé 94 vient en contact avec la butée de repos 101.
• - Le levier 98 sollicité par le ressort 99 appuie sur la pièce 100 en écartant d'une faible distance la came 90 de la roue d'entraînement 89 et son arrêt 96 entre en contact avec l'extrémité 97 de la bascule 76.

The cam 90 has then made a rotation of 180 ° and begins to move the pull tab 105, to the right, controlling the following operations:

• - The lever 110 pivots in the opposite direction, driving the roller 26 in a dextrous direction, the latter transports your sheet of paper over the members 18 downwards.
• - When the pocket is fully absorbed and the sheet laid flat, the roller 26 emerges from the sheet which falls in free fall on the alignment stop 27.
• - The control unit 130 controls at this time a stop of the drive motor for a period of about one second to ensure that this fall takes place without hindrance.
• - After this fall and the starting of the drive motor, the smooth periphery 90b comes into contact with the wheel 89 and slides on the latter.
• - The unit 130 commands a new stop of the drive motor. During this stop, the lever 110, biased by the spring 117 continues to pivot to allow the closing of the two drive rollers 29 and 30. The pull tab 105 then controls the retraction of the alignment stop 27 under the effect of the tension of the spring 102 acting on the arm 94. The periphery 90a provided with the toothing then again comes into contact with the toothed wheel 89.
• - The drive motor is started for a period which is a function of the desired insertion length of the paper and controlled by the unit 130. During this operation, the cam 90 is driven by the wheel 89 and the bent arm 94 comes into contact with the rest stop 101.
• - The lever 98 biased by the spring 99 presses on the part 100 while moving the cam 90 away from the drive wheel 89 and its stop 96 comes into contact with the end 97 of the rocker 76.

During the selection and extraction of a sheet from a given cassette and its introduction into the printer, the striking cylinder is therefore driven in only one direction.

The two stops of the drive motor controlled by the unit 130 ensure an unimpeded fall of the paper and a closing of the drive rollers 29, 30 in the stationary position of the sheet. It is understood that these two stops are not essential, if the shape of the cam 90 is chosen so that the paper has sufficient time to fall on the alignment stop 27 before the roller 30 rests on the roller 29 and so that the stop 27 is retracted immediately after the contact of the two transport rollers 29, 30.

As the pocket 10 is fully absorbed before the sheet can fall on the alignment stop 27, the fall takes place regularly. The transport mechanism 28 picks up this sheet in a predetermined position in order to introduce it in a controlled manner into the printer, thus ensuring exact positioning of the sheet on the striking cylinder 3.

Claims (6)

1. Sheet feeding device for printer or typewriter with movable carriage comprising a frame, one or more supports on which the sheets to be printed are stacked, an extraction mechanism, associated with each of the supports, intended to extract a support sheet for insertion into the printer, and a selection mechanism for activating one of the extraction mechanisms, characterized in that the selection mechanism comprises a feeler device capable of cooperating with the mobile carriage in order to determine the position occupied by the latter, this feeler device comprising at least one actuating member intended to activate, as a function of the position occupied by the carriage, one of said extraction mechanisms. 2. Device according to claim 1, characterized in that the feeler device is constituted by a set of levers comprising a number of selection levers equal to the number of extraction mechanisms, each of the selection levers being capable of cooperating with a part integral with the mobile carriage, when the latter occupies a predetermined position, so as to activate one of the extraction mechanisms. 3. Device according to claim 2, wherein each of the extraction mechanisms comprises an extraction control member, character-ized in that said selection levers are arranged so as to actuate one of the control members of extraction, when they cooperate with the integral part of the carriage. 4. Device according to claim 3, comprising a drive member for the selection mechanism connected to the drive means of the printer's striking cylinder, characterized in that each of the selection levers is arranged so as to be moved by said piece integral with the carriage from an inactive position to an active position in which it cooperates with the drive member, when the movable carriage occupies a predetermined position and in that the drive member is arranged so as to drive the lever selection switch in the active position to activate the corresponding extraction control member. 5. Device according to claim 4, characterized in that the drive member is constituted by a toothed wheel and in that each of the selection levers carries a toothing capable of cooperating with this toothed wheel when it is in the position active. 6. Device according to claim 5, characterized in that the toothing is carried by a pawl pivotally mounted on the selection lever and urged by an elastic element in the direction of the toothed wheel against a stop integral with the selection lever.

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