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(11) | EP 0 148 734 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A service unit intended to convert into packages the paper web processed by a printer supplied with a preformed paper support |
| (57) A service unit intended to be associated «in cascade» to a high-speed printer for
automatically converting the continuous paper web printed thereby into packages separated
from each other without causing any dead time during the work of the printer, the
number of the sheets forming the packages being either program-predetermined by the
service unit or directly determined by the printer through interfacing or printing
of suitable codes on the paper web. The service unit comprises a device for completely
disengaging from the printer when an interfacing between the two units is not available. The service unit comprises in combination: a paper transport assembly using transport holes and having a constant and adjustable maximum tension; an assembly for the connection with the transport head comprising a plurality of sensors for detecting the necessary data which vary according to the unit version; a paper guiding, folding and packaging assembly for forming the package; a paper web cutting assembly for separating the packages; a plane for holding the package being formed comprising a means for flattening the upper portion of the package, which plane can be program operated; a means for expelling the separated package; a means which can be extracted on request for facilitating the repositioning of the package on the package holding plane; a means for detecting the top of the package and other means and sensors necessary to the aim of the invention, the operation of which is controlled by an electronic unit comprising a microprocessor. |
[0001] "A service unit intended to convert into packages the paper web processed by a printer supplied with a preformed paper support"
[0002] This invention refers to a service unit intended to convert into packages the paper web processed by a printer supplied with a preformed paper support. As known in the art, in electronic data processing centers high-speed printers, the latest type of which is known in the art as the laser printer, are so fast as to make a supply and H collection of the processed paper web in separate packages uneconomic, as it is the case with the devices used at present, since this requires a great number of successive work stops. These work stops are necessary on the supply of a new package and the collection of the processed paper web package, when the forms are cut and the paper web is refolded for forming the successive package. Furthermore, the above mentioned devices for forming the new package are not always -as reliable as necessary. It is sufficient to note that the actual average operational speed of a high-speed printer as it is supplied by the manufacturer is about 50ia of the printing speed thereof.
[0003] As a result of the foregoing, a number of service units have been recently devised intended to be used in connection with high-speed printers. These service units are auxiliary assemblies intended to allow a continuous supply to the printing units and collection therefrom, thus allowing the high processing speed of these equipments to be fully used.
[0004] With regard to the service units connected to high-speed printers, two different concepts have been considered according to the way of supply, and more particularly:
- units for the collection from high-speed printers supplied by a partially preformed paper web reel;
- units for a continuous collection from high-speed printers supplied by packages formed by a preformed and folded paper web.
[0005] Both the above-mentioned operative concepts reach the aim of allowing a continuous collection from high-speed printers, but they have extremely different characteristics, as it is easily understood.
[0006] This invention, however, is based on the belief that in the practice the most effective method for transporting, nolding and handling the paper to be processed by the printers, at least in most cases, is using a number of packages of preformed forms, that is a continuous paper web comprising a plurality of "sheets" or "pages" defined by weakening lines transversal to the web intended to facilitate the possible tear separation of the sheets. This paper web is provided on both sides with a succession of equally spaced holes called "transport" holes. These holes have standard dimensions, that is the distance between the holes and the diameter thereof is of a standard type, and they are used for moving and positioning the paper web both in printers and in apparatus of other types. The preformed packages are now almost generally used also in high-speed printers owing to the following evident advantages thereof:
[0007]
- maximum convenience in moving the paper to be processed and the processed paper;
- simple storing;
- convenience in carrying out small productions requiring different supports; and,
- absence of dead times of supply when using the service units.
[0008] All the foregoing has carried to an accurate analysis of the problems and technological solutions already existing in this field. The results are as follows:
- units carrying out a previous cutting of the paper before packaging, which units, however, are not practically used at present due to the difficulty in refolding the paper for forming the package;
- units inherently having some basic features for a correct operation thereof, such as a constant transport tension, the possibility of "release" and the like, but also having inherent insuperable operative limitations due to the nature of the devices used. These limitations are as follows:
1) the possibility of working only with single webs, which means that these units are not able to work with a plurality of averlaying webs, a feature that is not a limitation if used in connection with a laser printer, since a printer of this kind operates on a single copy;
2) the impossibility of operating with extended transversal variations of the paper size;
3) an incorrect paper transport direction which involves the use of repeated guides for holding the paper web along the path thereof, with the relative problems concerning the change of the paper size, the delicate alignment of the units, a correct operation depending on the uniformity of the pressure exerted by the paper web; and,
4) the impossibility of carrying out small consecutive packages each comprising a number of sheets lower than 250/300 sheets, according to the paper consistency.
[0009] The optimal characteristics for solving this problem can be summarized as follows:
1) operation with a paper traction having a limited and adjustable maximum tension;
2) possibility of recovering the paper also in the "reverse" operation;
3) an extremely directional paper transport system not requiring intermediate guides, overcoming the problems of a perfect alignment and providing precise aims in the web path for carrying out measurements;
4) maximum flexibility in the variation of the paper transversal dimension;
5) possibility of operating with a number of overlaying sheets in order to extend this technology to other types of high-speed printers that are quickly gaining on laser printers;
6) possibility of carrying out even extremely small consecutive packages, thus allowing these units to be used also in data processing centers which, operating also with extremely fractioned printings, can be provided downstream with the printers of packages automatically separated for each printing program;
7) possibility of not being forced to word with an electronic interfacing with the printer, in that the user often has to face this real and sometimes depressing problem for different reasons which are not certainly technical reasons. This causes the cutting operations to be carried out as a result of the reading of either a clearly detectable reference or a graphic code which can be programmed by the printer user at a point of the paper web predetermined and standardized with respect both to the "edges" and to the transversal perforation defining the "sheets" and determining the folding during the formation of the package.
[0010] The unit of the invention has all the above-mentioned optimal requirements since it is the result of specific researches and selective experiences. This result was obtained by using origi---nal devices and expedients. These devices and expedients are as follows:
- paper web transport obtained with a "tractor" system which also allows the operation to be carried out with an adjustable maximum tension of the paper transport, with the possibility of immediate stop, release and reverse paper movement, through an original device and the construction of a "tractor" system optimal to this aim;
- a device for the "lateral guide" of the paper in the area of the package formation;
- a paper web cutting plane which has allowed the thickness thereof to be limited to a few millimeters;
- shape of the package holding and forming cage;
- use of a detector of the cutting plane operation;
- a package holding plane provided with a program- liftable and completely hidable "levelling" device and an equally completely hidable package positioning device;
- a sertes of sensors and detectors for specific applications; and,
- a sensor indicating the movement of the paper being supplied to the printer.
[0011] The unit and devices of the invention will be now described in detail with reference to the annexed drawings, wherein:
Figure 1 is an overall side view of the unit extremely simplified to show the construction and arrangement of the various members and main assemblies, showing in detail the printer supply sensor;
Figure 2 shows a funcional-executive diagram of the "tractor" moving and operating device;
Figure 3 shows a device for the lateral guide of the paper in the area of the package formation, which device is provided with a positioning system;
Figures 4 and 4a show the "head" of the unit provided with a "data detecting" assembly for carrying out the cutting on a graphic indication, a paper transport-guide-folding-compressing assembly, the shape of the containing cage and the arrangement relative to the cutting plane comprising the cage and the sensors;
Figures 5 and 5a show the cutting plane and the components thereof;
Figures 6a, 6b and 6c show the package holding plane;
Figures 7a and 7b show the original version of the "tractor"; and,
Figures 8 to 19 show a traditional working cycle of the unit.
[0012] Figure 1 shows the overall construction of the unit comprising a casing 1 which is an integral structure having spaces for receiving components and fittings such as sections of electric power, assemblies of controllers and pneumatic and electric controls. The bottom of casing 1 comprises a space la provided with rollers for moving the paper web being supplied to the printer and also comprising the original "sensor" for detecting the movement of paper 52. This sensor is shown in detail in Figure la and comprises a small wheel 52c made from a nonmagnetic material and having an antislip outer surface. Wheel 52c can freely rotate about support 52b therefor which allows the small wheel to engage the paper web being supplied to the printer and controlled during rotation by the movement of the tape.
[0013] The housing for the electronic unit is formed within 'casing 1 on supports 1b. The upper portion of casing 1 supports the protective shell lc and also the paper transport assembly 2 of which only the tractor, the connecting member 3 and the paper web tension sensing cylinder 4 are shown. The assembly for guiding the paper and folding, packaging and holding the package is referred to by reference 5 and the cutting plane is referred to by reference 6.
[0014] The package holding plane 7 is connected through the support arms to guides 9 which slide along rods 10 vertically placed and rigidly connected to the structure. The up and down movement of the assembly comprising members 9 and 8 is controlled by a chain 11 through a hooking system 12, which chain is operated by a nonreversible geared motor 13.
[0015] Cutting plane 6 is able to slide horizontally and it is controlled by a similar chain and geared motor device. The sliding rods are connected to the upper structure at the end thereof and the rear connection is clearly shown in Figure 1, while the front connection is shown in Figure 4 by reference 15; in the same figure the sliding rods are referred to by reference 14.
[0016] The package receiving plane 16 is shown in dotted lines since it is not essential to the concept of the unit of the invention together with its connection 16a to the structure.
[0017] Figure 1 shows also the two positions from which the paper can be fed to the unit and the two supplementary rolls 4a and 4b intended to allow the web to form a sufficiently sharp bend around sensing cylinder 4 along the path thereof from any feeding position to the transport assembly 2.
[0018] The function of sensing cylinder 4 is better shown in Figure 2 wherein cylinder 4 is connected at one end to an oscillating support 17a fixed to the unit casing and at the other end to straight rod 18 through a second oscillating support 17. Rod 18 can slide within guide 19 which is also connected to the unit casing. Stroke limiting members 20 have also been provided since the stroke is extremely reduced. A lever 22 is also connected to rod 18 through limiting members 21, which lever 22 is pivoted at 23 and operates rod 24 through limiting members 25. A double effect cylinder and piston assembly 26, the body of which is rigidly connected to structure 1, is also rigidly connected to rod 18. Rod 24 which is rigidly connected to supporting and guiding shaft 27 exerts a force on fork 28 containing friction wheel 29 which is free to turn about its axis and is made from a frictionally suitable material. Driven wheels 30 and 33 are supported by the body of housing 34 through axis 31 and 32. Wheels 33 and 30 are respectively connected to a motor not shown in the figure and, through a homokinetic joint, to the axis driving the paper transport member or "tractor". All the components shown in relative movement are mounted on rolling bearings to improve the sensibility thereof.
[0019] It can be understood that when driving wheel 33 is moved by the thrust exerted on friction wheel 29, this wheel 33 transmits its motion to wheel 30 thus starting the paper transport. This thrust of friction wheel 29 on wheels 30 and 33 is exerted by piston 26 by feeding air from side 26a thereof. This "transporting" action is opposed by the opposite component of the force exerted by the tensioned paper web turning about sensing cylinder 4. This force is a linear function of the paper web tension. Accordingly, the maximum paper transport tension, exceeding which the -friction wheel will completely slip, can be adjusted by suitably acting on the feeding pressure of piston 26 through port 26a. It is evident that, if the air is fed through port 26b instead of port 26a of piston 26 the rotation of axis 31 and accordingly the paper transport stops immediately, since the thrusting action of wheel 29 against wheels 30 and 33 has been interrupted.
[0020] The geometry and dimensions of the system are such that the paper transport adjustment effect can be controlled very well.
[0021] Furthermore, it should be noted that the rotational speed of driving wheel 33 is such that, when the paper transported is not in tension,thus not balancing the piston force, the paper transport speed is extremely higher than the printing speed of the printer. Accordingly, the service unit can carry out those "feedbacks" with respect to the printer that are indispensable in the cutting step, as it will be evident.
[0022] It should be noted that using this device, a change in diameter of friction wheel 29 does not involve any variation of the gear ratio between wheels 33 and 30, in absence of slippage, but at most it involves the need of either modifying or adjusting the length of rod 24.
[0023] It is evident that device 35 is intended to control the opposite rotation of driven wheel 30 with respect to the rotation determined by wheel 29. When device 35 starts to work wheel 29 is in the rest position. The strength of device 35 is clearly limited since its operation is temporary and limited to a fraction of a second, when necessary, during the cutting operation. The operation cf device 35 is similar to the operation of system 28 and 29, but friction wheel 29 is replaced by friction wheels 35a and 35b. These wheels are floatingly mounted and accordingly they can move on fork 35c. Thus, when electromagnet 35d exerts a pressure thereon they automatically engage both with wheels 30 and 33 and with each other. Return spring 35f causes carriage 35g to automatically return to the rest position when the electromagnet action has stopped.
[0024] Figure 3 shows the original device for the side guide of the paper in the package formation area. In this figure all the components are marked by letters s=left and d=right. The guides are directly attached to the tractor body through supports 36 and thus, when the transversal size of the paper web is changed, they follow the transversal movements of the tractors. Supports 36 have also attached thereto the body of double effect cylinder 37,piston 38 of which causes chute 39 to rotate angularly, which chute is pivoted at 40 to supports 36. Piston 37, depending on how it is fed, causes the chute to move either to the rest position R or to the operative position 0. The feeding ports of piston 37 are fed in parallel with piston 26 and accordingly on the starting of the paper transport the chute automatically reaches the operative position and viceversa. This feature is important in that in the rest position R this chute facilitates the positioning of the package in the holding area on the raising of the package in case of "repositioning".
[0025] Members 41 are electromagnetic vibrating bodies inducing a vibrating effect to the chutes for helping the paper transport. It should be noted, however, that even in operative conditions the engagement of the package with the chute is always sufficiently loose.
[0026] Figure 4 shows the "head" of the unit comprising main supports 42 secured to structural members 4 to which practically all the components of the head are connected.
[0027] Along the path of paper 43 connecting section 44 is placed which comprises a member made from a sheet of stainless steel comprising different elements according to the two possible "extreme" versions of the unit.
[0028] 1) In the normal version sensor 45 is a reflection photoelectric cell intended to control the "paper presence" and cause the unit to stop in case of breaking. Electrostatic discharging member 46 is intended to discharge the possible statical electricity stored by the paper before entering the folding head. In this version an electronic interfacing with the printer is necessary to count the number of the sheets, besides all the other components essential to the operation of the unit.
[0029] 2) The second version, wherein the cutting is controlled by a "graphic sign reading" and the electronic interfacing is unnecessary, also comprises:a reflection photoelectric cell 47 placed at the paper web transport holes for counting the holes and, accordingly, through the stored data on the longitudinal size of the sheets, also the sheet number; and, a reflection photoelectric cell 48 which should be able to move transversally to the sheet to be positioned in the graphic code reading area. Figure 4a is a schematic top view of the above-mentioned device wherein photoelectric cell 48 can slide along rod 49 pivoted at 50, thus allowing the cell to be easily removed from the ope- tative position.
[0030] This second version is completed by brush 51 which can also be easily moved and is intended to keep paper web 43 in contact with chute 44 even when the paper is not in tension. It should be noted that photoelectric cell 47 is rigidly fixed to chute 44 in that practically all units have a "stationary" paper side. In different cases it is sufficient to connect this cell to the tractor body similarly to supports 36 and form a suitable window on chute 44 to allow the photoelectric cell to "see" the paper on the transversal movement of the tractor. This second version is completed by sensor 52 of Figure 1 the aim of which will be described after having illustrated all the unit.
[0031] At this point the paper reaches the transport section comprising a tractor system having a moving axis 53 which is connected to driven wheel 30 of the friction device of Figure 3 through a homokinetic joint. The above-mentioned paper transport members placed at each side of the paper web cause the paper to move to paper guide 54 which, together with engaging chutes 55, rotating vanes 56 and limiting members 57 form the paper folding containing and packaging assembly.
[0032] The package containing cage is longitudinally defined by limiting members 57 which of course comprise a device for adjusting the distance between these two limiting members according to the sheet size. The rotation of vane shafts 56a and vanes 56, placed in turn along the whole length of the package and according to a precise helicoidal path, causes the pairs of sheets to be moved and pressed on the package which is being formed in the folding area.
[0033] Sensor 58 which is a reflection photoelectric cell is intended to keep the top surface of the package below e predetermined level by causing the package holding plane to lower to a certain extent each time that the package being formed reaches the cell. Sensor 59 which is also a reflection photoelectric cell is directly connected to the bars of cage 57 and starts to work only at the beginning of the cutting step to the aim described below. The shape of left cage members 57 should be noted, which members allow the cutting member to pass through the loop formed thereby, even maintaining the vertical "guide" of the package. This loop is centrally placed with respect to the thickness of cutting plane 60 which slides in turn on rods14 through guides 61. Sensor 62 which is rigidly connected to the right side of cage 57 detects the presence of the cutting plane within the package containing cage. A similar sensor, not shown in the figure, which is connected to the opposite side of the cage indicates that the cutting plane is approaching the loop forming side of cage 57 and, accordingly, that this cutting plane has crossed the whole "package area". Thus, this sensor causes the cutting plane to stop at the mouth of loop 57a.
[0034] The cutting plane referred to by reference 60 in Figure 5 is also an original member in that it comprises a single body having a rectangular shape and a constant thickness limited to a few millimeters. Guides 61 are secured to the outer sides of cutting plane 60, which guides 61 slidingly move along rods 14 which are rigidly secured to the structure. This "carriage" is moved by tabs 61a, as mentioned above, and carries two small carriages 63 at the front outer corners thereof. Carriages 63 support a steel cable 64 stretched therebetween. In the retracted position cable 64 is received within a groove formed on the edge of the cutting plane, while in the extended position this cable protrudes from that edge by some centimeters.
[0035] Carriages 63 are maintained in their seat by a pin passing both through the carriages and through the plane and cable 64. The carriage retaining pins slide within two slots formed on the body of the cutting plane. Carriages 63 are moved by two double effect cylinder and piston assemblies 63a having a suitable size, which assemblies can be operated either simultaneously or in succession, without changing the result or the efforts necessary to obtain this result. This "cutting blade" 64 is received within loop 57a on the outward stroke thereof from plane 60.
[0036] Figure 5a also shows the relative geometric positioning of the cutting plane and the package holding plane (reference 7 of Figure 1) which practically touch each other by means of completely retractile member 66.
[0037] It can already be understood which is the minimum level difference of the package being formed which can be obtained by means of the devices used and the minimum compatible level with respect to the paper folding and packaging system for a correct operation of the unit, particularly on the delicate cutting step and immediately after this step, especially in ca.se of extremely small packages. Of course, the drawing of Figure 4 is not a scale drawing but only a representative drawing.
[0038] Package holding plane 7 of Figures 6a-6b-6c comprises a supporting structure 68 connected to supporting arms 8 and completely covered by shaped members made from a metal sheet. The bodies of double effect cylinder and piston assemblies 69 are fixed to the above-mentioned structure and the pistons of these assemblies cause cylinder rod 70 connected thereto to rise. Thus, in the retracted position this rod will remain below the level of the package holding plane, as clearly shown in the figures. If the cylinders are fed from the opposite side the rod protrudes from the package holding plane by an extent sufficient to level off the top side of the package being formed, which is necessary at a certain height of the package due to the slight and inevitable side swelling due to the folding.
[0039] Sensor 70 is intended to indicate a slight movement of the rod with respect to the extended position thereof. Geared motor 71 is intended to operate package expellers 73 through a chain drive 72, which expellers protrude from the outer structure of the plane only on the package expulsion step. Sensor 74 detects the presence of the expulsors from the return thereof to the new expulsion from the plane.
[0040] The use of reference pins 75 and 75m is also original, which pins are controlled by simple effect pneumatic assemblies 66 using a return spring and simultaneously operated by push button 77. On request of the operator, by pushing push button 77 the pins protrude from the plane surface by some centimeters and after a predetermined and adjustable time, for example 10 seconds, they return into the seat thereof.These pins are intended to allow the package to be positioned. Pin 75 is placed on the stationary side, that is the side which does not move even during the variation of the transversal size of the paper and it is fixed to the structure of plane 68, while positioning pins 75m can move according to the longitudinal size of the plane, the pistons of which are supported by adjustable bracket 75s which is secured at the right place on the package edge at each size variation. These positioning pins protrudes through slots 75a. Pistons 66 controlling pins 75m are not shown in the drawings for clearness reasons.
[0041] Sensor 79 has only a safety function and it is intended to prevent the package deposit plane from touching any external body on the lowering of the package holding plane. This sensor immediately stops the lowering of the package holding plane.
[0042] Slot-shaped openings 78 formed in the protective shell of the package holding plane should be noted, which openings are intended to allow the end portions of bars 57 to reach loop 57a when the package holding plane is in the "up" position.
[0043] Figures 7 a and 7b are a diagrammatic view of the paper moving tractor assembly as it is realized to reduce the friction due to movement with respect to commercial models. As it can be seen this is an uncommon assembly wherein all the transport and translation motion is controlled by a rolling bearing.
[0044] As known in the art, a tractor comprises a supported chain 80 having a number of arms carrying pins 81 secured thereto. When the chain moves and the paper .is hold at the level of the pin base, these pins fit in the paper transport holes and thus the paper follows the chain movement. Of course, there is one tractor at each side of the paper web and these tractors move synchronously receiving the motion from a single shaft 82 through a keying, for example tab 83. The paper is held in place by a spring pad which is not shown in the drawings since it is not essential to the aim of this description.
[0045] The body of tractor 84 is supported, guided and controlled on the transversal translation thereof In respect of the paper by shafts 85 and 86. Shaft 85 comprises either a square thread, to act also as a guide, or a ball screw. Shaft 86 slides in a rectilinear ball bearing 87 integrally formed with body 84. The rotation of shaft 85 can be either manual or motor-driven. Transport shaft 82 is physically engaged, at the circumference thereof, with driven gear wheel 88 only through tab 83. Furthermore, it should be noted that shaft 82 is not subject to distortion during work owing to the low torque transmitted.
[0046] The gear wheels for driving chain 88 and driven chain 89 are mounted on the body of tractor 84 through rolling bearings and they are made from a plastic material. Transport pin supporting guide 90 is also made from a plastic material and secured to body 84 by means of screws. Member 91 acts as a chain stretcher since shafts 82 and 86 are placed at a fixed distance.
[0047] It is apparent now that each tractor is a carriage driven and supported by shafts 85 and 86, while shaft 82 is opposed only by the paper transport and the rotation of wheels 88 and 89 which occurs on rolling bearings, as mentioned above.
[0048] It should be noted that the inventor has preferred to design the reversible friction device of Figure 2 for moving the tractor, instead of using an electrically driven step-by-step motor, since the friction device has prooved more practical in all the working steps such as stopping of the unit, reverse operation, speed pickup and selfadjustment to the printing speed.
[0049] Figures 8 to 19 included show a traditional working cycle of the unit. Figure 8 shows the normal formation of the package when it has already reached a predetermined height. It should be noted that the rising member referred to by reference 66 in Figure 6 is in the "out" position.
[0050] Figure 9 shows the beginning of the cutting step comprising the program-controlled lowering of the package holding plane to a level which is slightly lower than the level of the cutting plane, and the successive paper transport stop control. At this point, before the cutting plane starts its opera-' tion, photoelectric cell 59 of Figure 4 verifies that the paper has not a slightly risen fold at the side of the cutting plane, since this could touch the sheet and determine an anomalous situation.
[0051] If the operative conditions are as described in the figure, cell 59 controls a "paper recovery" by an extent sufficient to allow the fold to take the shape shown in dotted lines in Figure 10.
[0052] Figure 10 shows the shape of the paper fold when the cutting plane starts its operation on the package. The dotted lines show the paper position "corrected" by a return movement successive to the fold shape of Figure 9. The full line shows a fold shape not requiring any correction on the paper by means of the return device. It should be noted that the cutting plane slightly touches the terminals of the cage and engage also with the "packaging" plastic vanes.
[0053] Figure 11 shows the cutting plane which has just "entered" the package by some centimeters and the unit that starts again the normal paper transport and folding. The time wasted for the possible repositioning of the paper and the cutting plane entering movement is about a second.
[0054] Figure 12 shows the cutting plane which continues to "enter" the package and simultaneously the package which continues to be formed on the top portion.
[0055] Figure 13 shows the cutting plane which reaches the opposite end of the package containing cage after having crossed the whole "package" and is immediately program-blocked by the relative sensor.
[0056] Figure 14 shows the package holding plane which rises again for packaging the package to be separated by the contrast between the cutting plane and the rising member referred to by reference 66 of Figure 6.
[0057] Figure 15 shows the cutting cable protruding from the front end of the cutting plane, cutting the paper web at the transversally perforated area and entering the loop formed in the cage. Successively the rising member returns to the seat therefor in the package holding plane.
[0058] Figure 16 shows the package holding plane which has reached the level of the supporting plane and, accordingly, expels the separated pachage by means of the suitable device.
[0060] Figure 18 shows the cutting plane which, after the cutting cable has returned to the seat thereof, leaves the package formation area depositing the package forced thereon on the package holding plane. In view of the limited thickness of the cutting plane in conditions of normal operation, that is with packages comprising at least 30 sheets, the package holding plane needs not be program-risen.
[0061] Figure 19 shows the same condition of Figure 18, but in this figure the package has reached level sensor 58 of Figure 4 and has already controlled a lowering of the package holding plane. It should be noted that the rising member remains within the package holding plane until the package is small.
[0062] From the foregoing it can be understood that to obtain extremely small packages in succession all the above-mentioned inventions are necessary to maintain the package formation in the optimal area as far as possible.
[0063] In the above-mentioned operative conditions it is possible to form packages each comprising up to 30 sheets using a paper having a medium consistency, while in operative conditions in which the packages comprise less than 30 sheets, experimentally up to 10 sheets, the unit program comprises a "package expulsion" after the cutting of some packages. This means that in the situation of Figure 15, wherein the package is over the extremely small cutting plane, there is only the expulsion of the cutting plane (the underlaying package is already "loose" due to the lowering of the levelling member) then passing directly to the situation of Figure 19 wherein the package holding plane moves upwards again to compensate the limited height of the small package which meanwhile has formed on the cutting plane. This occurs to allow the paper being folded to work always in the optimal package formation area.
[0064] Furthermore, it should be noted that in the conditions mentioned above, that is with extremely small packages, there is a direct passage from the situation of Figure 19 to the situation of Figure 9 for the operation of the cutting plane with the rising member in the "out" position.
[0065] Thus, it becomes evident that rising member 66 of Figure 6 as it is realized is extremely important owing to the irreplaceable function thereof in the package cutting step, particularly when the package comprises a limited number of sheets.
[0066] It is necessary to describe the operation of graphic code reader 48 which, together with sensor 47 of Figure 4, forms the assembly controlling the butting on the graphic reading. As mentioned above, either the reference sign or a graphic code should be made at a predetermined position in respect of both the edge of the sheet and the transversal perforated line. Sensor 48 detects the control signal while sensor 47 counts the transport holes from the beginning of the control signal. The sum of the above-mentioned data bearing in mind that the distance covered by the paper web to reach the folding area is constant depending only on the paper size and accordingly already being stored in the program, allows the cutting procedure to be started when the sheet having the "code" is already in the folding area, but not necessarily at the right side to carry out this cutting at the end thereof. Accordingly, if two or at most three white sheets, that is unprinted sheets are left downstream of the end-work sheet, the cutting will be certainly carried out at this "white" area.
[0067] It should be noted that the above-mentioned use of sensor 47 for counting the paper transport holes only from the cutting control detection is limitative for this sensor but sufficient to the aim of the invention. The use of this sensor is extended when using a service unit which is not provided with the electronic interfacing with the printer.
[0068] In this case sensor 47 continuously counts the paper transport holes and the data are used both for determining the number of the sheets forming each package and for measuring the paper web path in terms of "number of holes" in case of a graphic reference controlled cutting.
[0069] It should now be necessary to analyse the operation of the unit in the three possible "critical" conditions wherein the data exchange does not occur via interfacing and accordingly:
1) Printing unit stopping during the operation thereof: in this case the paper remains temporarily tensioned but without damages since the paper is calibrated; after a predetermined time that detector 52 signals that the printer has stopped not- requiring the paper supply, the electronic unit supplies a "transport stop" signal;
2) once the service unit has stopped following the stopping of the printer, when the printer starts again to work the electronic unit immediately receives the data from sensor 52 after the moving of the paper being fed to the printer and supplies a "paper transport" signals The possible small quantity of paper web printed during this time is easily "recovered";
3) in case of "alarm" by the service unit, either caused by an uncorrect folding in the package formation area or by the breaking of the paper web or any other reason, the electronic unit supplies a signal which can be used either indifferently or simultaneously as an optical or sound alarm for the operator.
[0070] Finally, it should be noted that a paper web transported by a tractor system is guided so well that it does not require any supplementary intermediate guides and, furthermore, easily tolerates reduced misalignments and imperfections of the parallelism which can occur in the normal working practice.
1.- A service unit intended to be associated "in cascade" to a high-speed printer
for automatically converting the continuous paper web printed thereby into separated
packages without causing any dead time during the printer work, wherein the number
of the sheets forming each package is extremely reduced and either program-predetermined
by said service unit or determined by said printer according to precise requirements
of use of the processed paper web both directly through an electronic signal interfacing
and more simply through the printing of suitable reference signs on said paper web,
or manually controlling the paper web cutting at any time, said service unit being
provided with a device for completely disengaging from said printer when an electronic
pulse interfacing between said two units is not available, said unit comprising in
combination: an integrally made framework for supporting and receiving the fittings
and components of said unit, a paper transport assembly using the transport holes
and comprising a device for adjusting the maximum paper tension provided with a paper
"release" device; a connecting assembly comprising a transport head containing a plurality
of sensors for detecting the data necessary to a correct operation of said unit, said
sensors being different according to the unit version, said assembly comprising also
a sensor placed on the paper being fed to said printer; a paper guiding folding and
packaging assembly for forming the package; a paper web cutting assembly for separating
the packages from each other; a plane for holding the package being formed comprising
a flattening means in the upper portion of said package, said flattening means being
program-extended and completely hidable below the level of said plane;an expulsion
means for expelling the separated package and a control-extractable means for guiding
the repositioning of the package on said plane; a means for detecting the package
height; a means for verifying the possibility of operation for said cutting plane;
a driving means and pneumatic assemblies for operating said assemblies; a supporting
means; a transport means; and, an electronic control unit for controlling the synchronous
operation of said various assemblies, devices and means and processing the data necessary
to said unit operation.
2.- The service unit according to claim 1, wherein said paper web is moved by means
of a "tractor" system operated by a mechanical clutch controlled by a system of counterreaction
induced by the transported paper web tension.
3.- The service unit according to claim 2, wherein the device for controlling said
clutch on the counterreaction induced by said transported paper web tension comprises
a sensing cylinder on which said paper web is forced to pass on the path thereof towards
the transport head and on which said paper web forms a sufficiently sharp bend or
sufficiently winds up, said rotating cylinder on which said paper web is forced to
pass having the supporting shaft thereof secured at one side to the unit support by
an oscillating support which allows the whole cylinder to move angularly and having
the opposite side supported and secured by a second oscillating support connected
to a rod sliding in a straight guide rigidly connected in turn to said unit structure,
said thus secured sensing cylinder being able to oscillate about said oscillating
support while the opposite end thereof is free to slide determining the sliding movement
of said carriage-rod in said straight guide, the stroke or movement of said carriage-rod
being limited by two resilient rings integrally formed with said rod and placed outwardly
with respect of the sides of said straight guide, thus forming a double stroke limiting
member defined by said guide structure, the rod of a double effect cylinder and piston
pneumatic assembly the outer body of which is rigidly connected to said unit structure
being also rigidly connected to said sliding carriage-rod, said cylinder and piston
assembly being intended to move the sliding end of said sensing cylinder in both possible
directions along the stroke allowed by said stroke limiting members through said carriage-rod
and with a strength adjusted by the feeding pressure of said pneumatic cylinder, said
carriage-rod operating the arm of a lever also pivoted to said unit structure at one
end and directly operating the paper moving clutch at the other end through a rigid
connection having a suitable and adjustable length and comprising a rod provided with
a length adjusting system, all said components being so arranged and controlled that,
when the pneumatic control assembly is fed from the "transport" side causing said
carriage-rod and said paper passage sensing cylinder to slide, said pneumatic assembly
operates said clutch through said lever and said rigid rod, thus starting the paper
transport, the component opposing said pneumatic cylinder action being developped
as said paper web is stretched owing to the winding thereof around said sensing cylinder,
said opposite component proportionally reducing the resulting "force" exerted on said
clutch and, accordingly, also the transport force to reach a condition of balance
between the force of said pneumatic piston and the component of the paper tension
induced by said piston corresponding to the maximum paper tension and the total slipping
of said clutch, said maximum paper transport tension being adjusted by adjusting the
feeding pressure of said double effect control assembly, the immediate "stop" to the
paper transport being clearly determined by feeding said pneumatic assembly from the
opposite side since the action exerted on said clutch has stopped.
4.- The service unit according to claim 1, wherein said tractor moving clutch comprises
a housing receiving two cylindrical steel wheels integrally formed with the shafts
thereof (which protrude from said housing) and free to rotate on rolling bearings
received within the side walls of said housing, said wheel shafts being parallel to
each other and placed at a certain distance for preventing said wheels from interfering
with each other, one of said two wheels being a "driving" wheel, that is a wheel directly
moved by a motor, the other of said two wheels being a "driven" wheel and moving the
tractor operating shaft through a homokinetic joint, the friction member between said
two wheels comprising at one side a cylindrical wheel covered with a suitable material
which is free to rotate on a supporting fork rigidly connected to a carriage sliding
in a straight guide placed in the side wall of said clutch receiving housing the movement
of which causes said friction wheel to disengage from or engage with said two steel
wheels, said guide having such a construction that when said carriage causes said
wheels to engage with each other and exerts a pressure thereon, said friction wheel
self-centers exactly in the tangential position with respect to said other two wheels,
said friction wheel supporting carriage being connected and then operated and controlled
by the friction control rod, a second carriage provided with a fork and practically
equal to the above-mentioned carriage but supporting two small friction wheels floatingly
mounted and free to rotate on said fork being placed at the opposite side of said
steel wheels and said main friction member, thus determining the self- alignment and
the mutual compression of the assembly comprising said four cylindrical wheels, the
"driven" wheel rotating in the opppsite direction with respect to the paper transport
and being intended to pull said paper backwards, said second carriage being held in
the rest condition by a coil spring.
5.- The service unit according to claim 1, wherein said side paper guides in the package
formation area comprise two chutes placed at each side of said paper web, each chute
being maintained in vibration at high frequency by an electromagnetic body directly
fixed thereto and comprising two pads having a slightly convex suitable shape hinged
at the top thereof tu two supports integrally formed with said tractors, thus being
able to follow said tractors during the movements thereof occurring at each change
of the lateral dimension of said paper web, said two chutes forming a funnel for the
paper in the operative position thereof and being held in said position by two double
effect cylinder and piston pneumatic assemblies having the cylinder bodies integrally
formed with the support of said chute and the rod driven by the piston integrally
formed with said chute by means of a hinge, said pistons being intended to open the
bottom of said chutes during the paper transport stopping step anf form a particularly
large opening in case of a return upwards of said package to the formation area after
a manual repositioning of said package on said package holding plane.
6.- The service unit according to claim 1, wherein said package receiving and forming
cage comprises a plurality of vertical equal bars at each side of said cape and particularly
the bars forming the outer side have such a shape as to form a horizontal loop then
resuming the preceding direction and position to end successively with a wide outward
connection of said cage, said loop being intended to receive the paper web cutting
member while the cage portion above and below said loop is intended to maintain in
guide both the package to be separated and the package to be formed on said cutting
plane.
7.- The service unit according to claim 1, wherein the entry of said cutting plane
in said package formation area depends on the control of a detector or sensor comprising
a reflection photoelectric cell integrally forned with the structure of said package
receiving cage which is intended to verify that the paper being folded, which has
temporarily stopped, is in such a position that the entry of said cutting plane will
not cause any damage to the fold, controlling in this case a rearward movement of
said paper web sufficient to avoid the above-mentioned effect.
8.- The service unit according to claim 1, wherein said paper web cutting plane comprises
a central monolithic body having a rectangular shape and a constant thickness, four
guides being fixed to the outer sides thereof, two at each side, for supporting and
moving said plane on the movement thereof, said plane thus becoming an extremely thin
carriage up to three millimeters in thickness, two small carriages having a shape
embracing the central body of said cutting plane and placed at the front side thereof
maintaining a steel cable stretched in a central position with respect to the thickness
of said cutting plane, said two cable holding carriages being held in position by
a through pin passing from the opposite side to the attachment of said cable and sliding
in a slot formed in the plane body, thus allowing said cable and said pins to maintain
said two carriages in engagement with said cutting plane, said steel cable covering
the whole width of said plane being received in the retracted position thereof within
a groove formed in the front edge of said cutting plane while, in the extended position
thereof, said cable protrudes from said cutting plane by some centimeters, said cable
holding carriages being moved each by a double effect cylinder and piston pneumatic
assembly and said above-mentioned slot also being intended to limit the stroke of
said carriages.
9.- The service unit according to claim 1, wherein the member for levelling the package
being formed and which operates when said package has reached a given height to flatten
the upper portion of said package thus eliminating the side swellings due to the fold
comprises a cylindrical body supported at the ends thereof by two double effect cylinder
and piston pneumatic assemblies, the bodies of said cylinders being rigidly secured
to the structure of said package holding plane and thus placed that when the pistons
are in the retracted position the rising rod is received within a cavity formed in
the upper surface of said package holding plane without protruding therefrom, said
rod protruding from said plane by some centimeters and taking a parallel position
in respect thereof when said cylinder and piston assemblies are fed from the opposite
side, the position of said rising rod in respect of said package holding plane being
such to correspond to the vertical of the longitudinal paper guide which becomes also
the center line of the package being formed.
10.- The service unit according to claim 1, wherein the assembly of extractable limiting
members intended to reposition said paper package on said package holding plane comprises
three pins operated by three spring return simple effect cylinder and piston pneumatic
assemblies controlled by an automatic distributor placed inside said package holding
plane and an adjustable air discharge system, two of said package repositioning pins
being mounted transversally to said package, that is usually along the longer dimension
thereof, while the third of said pins is mounted at the head of said package which
is normally a fixed reference, the body of the pneumatic cylinder operating said head
pin being rigidly secured to the supporting structure of said plane, the limiting
member comprising a small cylinder of a plastic material directly fixed to the piston
rod protruding from said plane through an .opening formed in the covering thereof,
the transversal limiting members comprising a pair of similar devices having the body
of said two pneumatic assemblies fixed to a bracket moving in respect of the surface
of said package holding plane and provided with a tightening system for blocking said
bracket in the right position after a change of the package size, the respective pins
protruding from the surface of said package holding plane through two slots, all the
above-mentioned members being so arranged with respect to each other that in the rest
position the package limiting members are below the surface of said package holding
plane, while operating said pneumatic distributor said pins protrude by about two
centimeters thus forming a safe reference for manually repositioning said paper package.
11.- The service unit according to claim 1, wherein the auxiliary assembly of detectors
for carrying out the paper web cutting operation on a graphic indication comprises
an assembly of two reflection photoelectric cells, the photoelectric cell intended
to detect the graphic signal being movable transversally to said paper web through
a device for tightening the detector to the supporting rod for allowing a preventive
positioning in the area where the graphic indications will be printed, said photoelectric
cell supporting rod being hinged at one end so that rotating about said hinge point
said rod leaves the paper web area without becoming an obstacle both when it is used
and in the initial paper web positioning step, the second reflection photoelectric
cell being placed in line with the transport holes and fixed at the inner side thereof
through a bracket to the paper passage support which is provided with a suitable opening
allowing said photoelectric cell to count said transport holes, said counting or the
partial use of said counting occurring electronically.
12.- The service unit according to claim 1, wherein the sensor for detecting the movement
of the paper being fed to said printer comprises a wheel made from a nonmagnetic material
and having an outer antislip surface, said wheel being free to rotate about the support
thereof, said support comprising an arm hinged at the top for allowing, by an oscillating
movement,said wheel to rest by gravity on the paper web feeding said printer, said
wheel being rotated by said paper web when the printer calls said paper web back for
printing, said wheel comprising a plurality of magnetic inserts which during rotation
slightly touch a proximity sensor of a magnetic type which thus registers the wheel
movement and the successive "open" and "close" conditions, the logic of the signal
being processed by the electronic unit which can thus clearly detect the moving or
the resting condition of said paper web.