DEVICE FOR THE AUTOMATIC LOADING OF A PAPER ROLL IN A PRINTING DEVICE AND RELATIVE PRINTING DEVICE

Abstract: The device comprises a housing in which to insert a paper roll on which to print data; a feed roller (33) and a plurality of feeding rollers pairs (53, 54, 88, 89) for automatically feeding the leading edge of the strip of paper of the roll along a guide path; a rewinder sprocket (60) with a longitudinal slit (57) for receiving the leading edge of the strip of paper (306) and for securing the paper to the sprocket in this way. The sprocket (60) automatically positions itself, irrespective of how oriented on insertion in the device, with the slit disposed so as to be entered by leading edge of the strip of paper (306) at the outlet of the guide path, after passing through the printing area.

Description: TITLE "DEVICE FOR THE AUTOMATIC LOADING OF A PAPER ROLL IN A PRINTING DEVICE AND RELATIVE PRINTING DEVICE" TEXT OF THE DESCRIPTION Field of the invention - The device according to this invention may be used in all the printing devices that provide a document printed on a medium in the form of a strip wound in a roll, such as a cash slip or a receipt, typically employed in commercial transactions. Related technological art - Printing devices of the type described above are widely known, such as for example POS (Point Of Sale) terminals, cash registers, cash dispensers or automatic tellers, terminals for credit cards, etc. which, at the end of an operation more properly called "transaction", record on a medium (typically a strip of paper wound in a roll, henceforth referred to as paper roll) the data characterizing the transaction completed, thus printing a receipt or slip to be given to the customer. The data in question are generally also recorded on a second paper roll, which remains inside the device and constitutes what is known as the "journal" or a summary of the transactions carried out, designed for use for accounting and/or tax purposes. The paper rolls have a limited duration and therefore need to be substituted regularly, by loading a roll of blank paper in the equipment after opening a door panel and taking out the roll that has been finished or completely filled with data. The loading operation requires insertion in an appropriate housing of the blank roll and manual feeding of the leading edge of the paper strip, fitting it carefully, along a determined path from where it will be taken first to the printer working area and then to a cutter or rewinder, depending on whether the paper roll is the one on which receipts are printed or the one on which the "journal" record is printed. This loading operation is intrinsically rather complicated, on account of the paper path inside the equipment being difficult to get at, with the risk of the paper jamming as a result of not being loaded properly. In addition, it generally has to be done while the customer is waiting to claim his slip, with resultant inconvenience and loss of time. Summary of the invention - The object of the present invention is that of defining a device that permits automatic loading of the paper roll for the printing of receipts and of the roll for the printing of the "journal" in a printing device, without any other action on the part of the operator apart from that of inserting in random manner the paper roll in an appropriate housing, thus making the operation simple, reliable and fast. A further object of the invention is that of defining a device for the automatic loading of the paper roll for printing of the "journal" in a printing device, that produces, again automatically, fitting of the leading edge of the strip of paper on the sprocket for automatic rewinding, regardless of position of the sprocket at the start of loading. Yet a further scope of the invention is that of defining a printing device comprising a device for the automatic loading of a paper roll, as defined earlier. The above objects are obtained by means of a device for the automatic loading of a paper roll in a printing device and a printing device, as described in the main claims. These and other objects, characteristics and advantages of the invention will become apparent in the course of the following description of a preferred embodiment, provided as a non-exhaustive example, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 - Is a simplified lateral view of a first embodiment of the device according to the invention, during the loading step. Fig. 2 - Is a simplified sectional view of a detail of a first embodiment of the device according to the invention, during the loading step. Fig. 3 - Is a simplified lateral view of a first embodiment of the device according to the invention at the end of the loading step. Fig. 4 - Is a simplified lateral view of a second embodiment of the device according to the invention, during the loading step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Fig. 1 is a simplified lateral view of a first embodiment of the device 20 for automatic loading of a paper roll in a printing device 10 according to the invention, during the step of loading of a paper roll 30a, consisting of a strip of paper 30b wound counterclockwise on a cylindrical core 30c. The printing device 10, in the example illustrated hereinafter, consists of a printing terminal, connected to a central processing unit (not shown in the figure), for local printing of a cash slip on a paper roll or, alternatively, of a receipt or other document on a single sheet (including, for example, a cheque) simultaneous with the printing of a "journal" on a paper roll. The example chosen is purely indicative, though by no means restrictive, as the printing device 10 can be a cash register or a Point Of Sale terminal or any printing terminal for the recording of transactions on a paper roll. The printing device 10 comprises, in addition to the device 20, a bottom structure 21 connected with a pair of transversal side plates 22, 23, a casing 24 provided with a door panel 25, a printing module 26 mounted on a sliding carriage 27, a device 28 for feeding of a single sheet. The device 20 for automatic loading of the paper roll 30a is constituted by a plurality of components that will be described below with reference to Figures 1 and 2. The blank paper roll 30a is housed in a housing 31 , defined towards the bottom part by a base 32 of essentially semi-circular cross-section belonging to the bottom structure 21 , and laterally by the pair of side plates 22, 23. Located at the lowermost point of the said base 32 is a feed roller 33, comprised by a shaft 34a rotatingly connected with the pair of side plates 22, 23, whereon a rubber roller 34b has been keyed and which bears, secured at one end, a first gear wheel 35. A lid 8a, free to rotate around a pin 48b through the effect of its own weight, rests upon the outer surface of the roll 30a through an arc of roughly 90°, in continuation of the curving profile of the base 32. A deflector 77, pressed resiliently by a spring 59 against the paper roll 30a, possesses at one end a finger-like element 76, which acts as an abutment against the paper roll 30a and is arranged so as to separate the leading edge of the strip of paper 30b from the roll 30a, and a surface 78 with a slightly curving profile arranged according to the extension of the finger 76 so as to act as a guide for the leading edge of the strip of paper 30b. The first gear wheel 35 meshingly engages with a second idle gear wheel 36 (to simplify the figure and the description, all reference has been omitted to the rotation pin of this second gear wheel and of all the subsequent ones, not being essential for understanding of the device to those skilled in the sector art). The second gear wheel 36 receives its motion from a first motion transmission element 37, comprising a third external gear wheel 38a, a third internal gear wheel 38b meshingly engaged with the second gear wheel 36, and a first pulley 50, all integral with each other. The first pulley 50 is linked by a timing belt 51 with a second pulley 52; the first motion transmission element 37 in turn receives its motion from a second motion transmission element 39a, comprising a fourth external gear wheel 39b and a fourth internal gear wheel 39c, meshingly engaging with the third external gear wheel 38a. The fourth external gear wheel 39b meshingly engages with a fifth gear wheel 43 which constitutes the pinion of a motor 41 (which can be of the stepping type or direct current type, for instance); the third internal gear wheel 38b is also engaged with a sixth gear wheel 40, integral with a first feeding roller 53 against which a first counter-rotating roller 54 is resiliently pressed to define a first pair 53, 54 of feeding rollers; the sixth gear wheel 40 in turn meshingly engages with a seventh idle gear wheel 44, in turn meshingly engaged with an eighth gear wheel 45, also integral with a second feeding roller 88 against which a second counter-rotating roller 89 is resiliently pressed to define a second pair of feeding rollers 88, 89. The printing module, represented in the figure as a printhead 26, faces a rigid element 81 , which acts as a platen if the printhead 26 is of the impact type, thereby defining an intermediate passageway 82 between the first pair of feeding rollers 53, 54 and the second pair 88, 89. Also partly facing the rigid element 81 is a guide 80, made of a thin, suitably-shaped metallic sheet. A movable guide 83, of approximately triangular cross-section, on rotation around a pin 85 urged by the action of a pin spring (not shown in the figures), can assume a first alignment position wherein a lower surface 86 thereof closes the passageway 82, or a second alignment position wherein an upper surface 87 thereof is aligned along the passageway 82. In the first alignment position, the movable guide 83 directs the leading edge of the strip of paper 30b in the direction of the second pair of feeding rollers 88, 89, by way of the lower sur ace 86, and hence towards a fixed guide 84, of substantially curved shape. The second pulley 52 is linked by a frontal clutch 42 (of the disk type, for example) with a ninth gear wheel 46, which is in turn meshingly engaged with a tenth gear wheel 47; the tenth gear wheel 47 is integral with a rewinding sprocket 60 for rewinding of the strip of paper. The sprocket 60 consists substantially (see Fig. 2) of a cylindrical body 61 , having a longitudinal axis around which it is free to rotate and which bears attached perpendicularly to one end a circular flange 55, the outer circumference of which has been provided with a pawl 56 in a given position. The clutch 42 is regulated to transmit a torque to the sprocket 60 and make it rotate around its longitudinal axis, only if the resisting torque offered by the sprocket 60 is lower than a determined maximum value, beyond which the clutch slips and the sprocket's rotational movement ceases. The cylindrical body 61 is provided with a longitudinal slit 57 the purpose of which is to accommodate the leading edge of the strip of paper 30b during automatic loading, so that it passes right through the cylindrical body 61 , coming out at the side opposite that at which it entered, in such a way as to attach the strip of paper 30b securely to the rewinding sprocket 60. The entrance to the slit 57 is substantially aligned with the position of the pawl 56. The sprocket 60 is removably inserted in an appropriate seat 63 in the pair of side plates 22, 23, between which it is free to rotate, with its longitudinal axis disposed perpendicular to the side plates 22, 23. The door panel 25 is fastened by a hinge 62, around which it can rotate in order to grant access to the device 20 for automatic loading of the paper roll 30a, and is provided with an actuator arm 70 (see Fig. 3), operation of which will be described in detail below. A lower movable guide 64 is constituted by a substantially rectangular-shape tongue 65a, connected to an arm 66 disposed approximately at right angles thereto, and hinged along a first axis 67 with respect to the pair of side plates 22, 23, and by a tab 65b arranged on the same plane. The guide 64 is resiliently pressed by means of a spiral spring 68 linked to the arm 66 against a stop 69 provided in the side-plate 22, which is in pressing contact with the tab 65b. In this position, one end 71 of the tongue 65a opposite the first axis 67 is aligned with the slit 57 produced in the sprocket 60. An upper movable guide 72, also substantially rectangular in shape and hinged along a second axis 73 with respect to the pair of side plates 22, 23, rests by gravity on the tongue 65a with one end 74 opposite the second axis 73, so as to define in conjunction with the tongue 65a of the lower movable guide 64 a guide area 75 converging in the direction of the slit 57. Operation will now be described of the device during the step of loading the paper roll 30a, again with reference to Figs. 1 and 2. To effect automatic loading of the paper roll 30a, an operator is required to perform three successive operations: 1 ) insert the roll in the device, 2) insert the rewinder sprocket in its seat, 3) start the automatic loading sequence. 1 ) The paper roll 30a to be loaded is inserted, after opening both the door panel 25 and the lid 48a, in the housing 31 , ensuring that it is disposed so that the strip of paper may be unwound by a counterclockwise rotation. The leading edge of the strip of paper does not have to be fitted in any particular way, nor be disposed with any great accuracy, it sufficing to ensure that it is approximately facing upwards so as ideally to be covered by the lid 48a when the latter is shut. 2) The sprocket 60 is inserted in its seat 63 provided in the pair of side plates 22, 23 without any concern for disposing the entrance of the slit 57. 3) When these first two simple operations have been completed, the operator must start the automatic loading by pressing an appropriate button on the keypad (not shown in the figure) of the printing device 10: this will command rotation of the motor 41 so that the pinion 43 will turn in the counterclockwise direction, and a) through the combined action of the gear wheels 39b, 39c, 38a, 38b, the pulleys 50 and 52 and the further gear wheels 46 and 47, will result in the rewinder sprocket 60 rotating counterclockwise; b) through the combined action of the gear wheels 39b, 39c , 38a, 38b, 36 and 35, will cause the feed roller 33 to rotate clockwise, so that the paper roll 30a will rotate counterclockwise as a result. Let us now examine in detail the consequences of the two actions a) and b). a) Rotation of the sprocket 60, starting from the position in which it was inserted in the seat 63, continues until the pawl 56 on the outer edge of the first flange 55a comes into contact with the tongue 65a, in turn held in this position by the tab 65b in contact with the stop 69. Under these conditions, the resisting torque offered by the sprocket 60 increases beyond the maximum value for which the clutch 42 has been regulated, so that as the second pulley 52 continues to rotate through effect of rotation of the motor 41 , the clutch 42 starts to slip, thereby preventing rotation from being transmitted to the ninth gear wheel 46 and, through the latter, to the sprocket 60, which as a result stops in a position suitable for receiving the leading edge of the strip of paper 30b, namely with the entrance of the slit 57 aligned with the converging guide area 75. b) Counterclockwise rotation of the paper roll 30a results in the leading edge of the strip of paper 30b, which was initially at the top, turning gradually counterclockwise until it comes into the vicinity of the finger 76 of the deflector 77, which separates the leading edge of the strip of paper 30b from paper roll 30a and guides it, with the surface 78, to the first pair of feeding rollers 53, 54 Through the action of the first pair of feeding rollers 53, 54, the leading edge of the strip of paper 30b first enters the passageway 82 and is then deflected by the lower surface 86 of the movable guide 83, which is held in the first alignment position by the action of the pin spring In this first alignment position, the lower surface 86 provides guidance for the leading edge of the strip of paper 30b to the second pair of feeding rollers 88, 89 The second pair of feeding rollers 88, 89 then directs the said leading edge first towards the fixed guide 84 and then to the converging guide area 75 between the lower 64 and upper 72 movable guides, and subsequently to the slit 57 in the sprocket 60, which has in the meantime been brought into the correct alignment position, as earlier described At this point, the operator has only to check that the leading edge of the strip of paper 30b, going through the slit 57, passes right through the cylindrical body 61 so as to be fixed correctly in place, and then, this done, put an end to the loading operation, for example by pressing a second time the same button as used to start the loading operation, and close the door panel 25 Closing of the door panel 25 (see Fig 3) lowers the actuating arm 70 which presses on the tongue 65a pushing the tab 65b away from the stop 69, in contrast with the contrary force exerted by the spring 68, the removal of the tongue 65a and consequently of the tab 65b from the stop 69 also frees the pawl 56 of the sprocket 60 Accordingly, when the motor 41 starts rotating again for feeding of the strip of paper 30b, there being no more slippage of the clutch 42, the rewinder sprocket 60 will also be able to rotate for rewinding of the paper, thereby maintaining under a tension, the value of which is determined by the characteristics of the slip clutch 42, that part of the strip of paper 30b that is downstream of the second pair of feeding rollers 88, 89. The tension of the strip of paper in the part upstream of the second pair of feeding rollers 88, 89, by contrasting the action of the pin spring, tends to produce rotation around the pin 85 of the movable guide 83, which thus becomes disposed according to the second alignment position to allow transit into the passageway 82 of single sheets introduced through an entrance 29 of the single sheet feeding device 28. A second embodiment will now be described of a device 120 for the automatic loading of a paper roll in a printing device 110 according to the invention, a simplified lateral view whereof is shown in Fig. 4, wherein like numbers to those of Fig.1 are used to indicate like elements. This second embodiment concerns a printing device 110 comprising a paper roll 30a for the printing of receipts only, wherein the printed area of the strip of paper 30b must be removed from the printing device 110, cut and given to a customer, unlike the printing device 10 of the previous example, in which the "journal" was printed and the strip of paper 30b rewound after printing. The printing device 110 lacks therefore that part of the device needed for rewinding of the strip of paper 30b after printing, but instead possesses a cutter 90, of known type, arranged downstream of the second pair of feeding rollers 88, 89; additionally the movable guide 183 possesses a lower surface 186 which conveys the strip of paper to a slot 91 provided in the casing 24 from where it may be taken by the operator after cutting, instead of to the fixed guide 84. The method of operation of this second embodiment is similar to that already illustrated for the first embodiment (obviously without the operation of inserting the rewinder sprocket) up to where the leading edge of the strip of paper reached the point where it is gripped by the second pair of feeding rollers 88, 89. At this point the lower surface 186 of the movable guide 183 conveys the leading edge of the strip of paper to the slot 91 , while the cutter 90 sees to it that the strip of paper is cut at the end of printing. Naturally changes may be made to the invention described in the foregoing without exiting from the scope of the invention. For example, a printhead not based on the impact technology may be used, examples being an ink jet or thermal type printhead. Or the device of the invention may be used for the automatic loading of a medium constituted (instead of by a strip of paper) by a strip of limited thickness of a flexible material wound around a core to form a roll, such as for example an ink ribbon for use in an impact or thermal transfer type printer, or a plastic tape for use in an embossing type labelling machine, or a magnetic ribbon for use in a magnetic reproduction/recording device. Or again, further pairs of feeding rollers may be added or motion transmission means other than gear wheels, such as chains or belts, may be used. In short, while adhering to the principle of this invention, details of the construction and the forms of embodiment described and illustrated in the foregoing may be amply modified without exiting from the scope of the invention.

Claims: CLAIMS 1. A device for the automatic loading of a paper roll (30a) in a printing device (10) comprising: - guiding means (77, 80, 83, 84, 64, 72) for guiding said paper along a defined path, feeding means (33, 53, 54, 88, 89) for feeding said paper along said defined path, rewinding means for rewinding said paper roll, said rewinding means comprising a sprocket (60) having a substantially cylindrical body (61 ) with a longitudinal slit (57) suitable for accommodating said paper and a longitudinal axis of rotation, and driving means (41 ) for selectively driving said feeding means and said rewinding means, characterized by the fact that said guiding means comprise a first movable guide (64) resiliently pressed against a stop (69) in a determined position so as to create a guide area (75), and that said sprocket (60) is made rotate by said driving means around said longitudinal axis of rotation from a starting position whatsoever to a final position so that said slit (57) is disposed towards said guide area, in such a way that said paper fed forward by said feeding means along said guide area is inserted in said slit. 2. A device as described in claim 1 , further comprising means for transmitting the motion from said driving means (41 ) to said sprocket (60) to make said sprocket rotate around said longitudinal axis of rotation, characterized by the fact that said motion transmission means comprise a clutch (42) placed between said driving means and said sprocket to transmit a torque lower than a maximum value, so that said sprocket is made rotate only if it possesses a resisting torque value lower than said maximum value. 3. A device as defined in claim 2, characterized by the fact that said sprocket (60) also has a substantially circular flange (55) the outer edge whereof is shaped so as to form a pawl (56) suitable for coming into contact with said first movable guide (64) pressed resiliently against said stop (69) in said determined position, so that when said pawl (56) comes into contact with said first movable guide (64) pressed resiliently against said stop (69) said resisting torque exceeds said maximum value, causing the slippage of said clutch (42) and the resultant cessation of rotation of said sprocket. 4. A device as defined in any one of the foregoing claims, wherein said printing device (10) comprises a casing (24) provided with a door panel (25) permitting access to a housing (31 ) into which said paper roll (30a) is loaded, said door panel possessing an actuating arm (70), characterized by the fact that when said door panel is closed said actuating arm removes said first movable guide (64) from said stop (69), so that said pawl (56) of said flange (55) of said sprocket (60) is no longer capable of coming into contact with said first movable guide. 5 A device as defined in any one of the foregoing claims, wherein said printing device (10) comprises a bottom structure (21 ) and a pair of side plates (22, 23), perpendicular to said bottom structure, which define said housing (31 ) for said paper roll (30a), characterized by the fact that said housing has a curving bottom (32) in the centre of which is a feed roller (33) upon which said paper roll presses with all its weight, so that a rotation of said feed roller is capable of determining a proportional counter rotation of said paper roll. 6. A device as defined in claim 5, characterized by the fact that it additionally comprises a movable deflector (77) having a finger-like element (76) at one end, pressed resiliently against said paper roll (30a) in a position downstream of said feed roller (33), so that by means of cooperation with said feed roller it is capable of unwinding said paper roll. 7. A device for the automatic loading of a paper roll (30a) in a printing device (10), comprising: guiding means (77, 80, 83, 84, 64, 72) for guiding said paper along a defined path, feeding means (33, 53, 54, 88, 89) for feeding said paper along said defined path, driving means (41 ) for selectively driving said feeding means and said rewinding means, wherein said printing device comprises a bottom structure (21 ) and a pair of side plates (22, 23), perpendicular to said bottom structure, which define a housing (31 ) for said paper roll, characterized by the fact that said housing (31 ) has a curving bottom (32) in the centre of which is a feed roller (33) upon which said paper roll (30a) presses with all its weight, so that a rotation of said feed roller is capable of producing a proportional counter rotation of said paper roll. 8. A device as defined in claim 7, characterized by the fact that it also comprises a movable deflector (77) having a finger-like element (76) at one end, pressed resiliently against said paper roll (30a) in a position downstream of said feed roller (33), so that by means of cooperation with said feed roller it is capable of unwinding said paper roll. 9. A device as defined in claim 7 or claim 8, characterized by the fact that said printing device (10) further comprises a cutter (90) for cutting said paper of said paper roll (30a). 10 A device as defined in any one of the foregoing claims, wherein said printing device (10) further comprises a printhead (26), characterized by the fact that said printhead is of the needle type. 1 1. A device as defined in any one of the foregoing claims, characterized by the fact that said printing device (10) further comprises a device (28) for feeding a single sheet along a path. 12. A device as defined in the previous claim, characterized by the fact that said path of said single sheet partly coincides with said path defined by said paper roll (30a). 13. A device as defined in claim 11 or claim 12, characterized by the fact that said printing device (10) further comprises a second movable guide (83) having an upper surface (87) and a lower surface (86), and that second movable guide can selectively assume a first position for guiding said paper roll with said lower surface (86), and a second position for guiding said single sheet with said upper surface (87). 14. A printing device (10) for printing on a paper roll (30a), characterized by the fact that it comprises a device (20) for the automatic loading of said paper roll according to any one foregoing claims.

Inventors: GIARDINO EMILIO, PACE PIERO, PREVIGNANO PAOLO, GIARDINO, EMILIO, PACE, PIERO, PREVIGNANO, PAOLO
Applicants: GIARDINO EMILIO, OLIVETTI & CO SPA, PACE PIERO, PREVIGNANO PAOLO, GIARDINO, EMILIO, ING. C. OLIVETTI & C., S.P.A., PACE, PIERO, PREVIGNANO, PAOLO
Application year: 1996
Main classification: B41J15
IPC codes: B41J15