EP0677472B1 - Finishing machine for printed sheets - Google Patents

Abstract

Printed sheets emerging from a printer or copier are received by pairs of wheels (30, 32) which are rotating at the paper speed. A detector (34) senses the leading and trailing edges of each sheet of paper and slows down speed control wheels (36, 38) such that the paper drops into a pile (16). An electromagnet vibrates the sides of the pile container (48) to produce good alignment and the paper then passes to jaws (64, 66) which rotate to a vertical position. From this position horizontal jaws (68, 70) take over and convey the paper to a gluing roller and covering station. <IMAGE>

Description

The present invention relates to a finishing machine for printed sheets delivered individually in rapid succession by a reproduction machine such as a printer or copier and for making them into a booklet, booklet or brochure.

Modern printers are able to produce reproductions, page by page, at very fast rates of up to more than a hundred pages per minute and more. Instead of always reproducing the same page in a work cycle, as is the case with copying machines or with offset printers, these machines successively produce complete sets of pages of a work, which often has to be made up in a booklet , booklet or brochure.

Finishing machines are certainly available for making stacks of sheets in a booklet, booklet or brochure. When you want to present the booklet, the booklet or the brochure in a cover, these finishing machines include a gluing and nesting station in which a stack of sheets is first glued onto a wafer by passing over a rotating roller partially immersed in liquid glue, and the cover is then applied against the glued edge of the stack and folded around it. In view of the irregularity with which the sheets appear in a stack, and in order to obtain properly aligned edges of the finished product, it is then necessary to cut the edges of the sheet stack and of its cover. The finished product therefore no longer has the dimensions of the sheets as they come out of the reproduction machine, for example in DIN 4 format. Furthermore, the stacks of sheets are loaded manually in the finishing machine, which not only requires a prior assembly by piles of the sets of sheets leaving the reproduction machine, but also human intervention for the transport of each assembled pile in the finishing machine.

Patent EP-A-0 453 743 describes a finishing machine in which the stacks of sheets, held by a pair of jaws in edge position, are successively transferred through a sheet picking station, milling stations , polishing and gluing a stack wafer, and finally stacking the stack in a cover. To facilitate these successive operations, means are provided for positioning the various work planes relative to the jaw movement plane.

The finishing machine according to the present invention overcomes all these drawbacks. According to the invention, the finishing machine comprises in succession: a station for taking care of the sheets delivered by the reproduction machine; a device for controlled slowing down of the sheets received from the pick-up station; a flat stacking station for slowed sheets; means for aligning the stacked sheets; a device for clamping the stack of aligned sheets; a device for rotating the stack clamped from a flat position to an edge position; and a device for gluing a section of the stack and / or for nesting the stack in a cover. By this combination of means and devices possibly known per se, a continuous and fully automatic production line is obtained from the reproduction machine to a terminal station which may be a collection station for the finished product. If you take into account the speed with which the leaves come out of the reproduction machine, for example 1 meter per second or more, this result is quite remarkable. In fact, at such a forward speed, the sheets behave in a practically random manner unless they are forced to be guided. Also, to stack the leaves thus ejected, they must first be slowed down. In order to stack the sheets in good conditions allowing correct alignment in the stack, the invention provides for a controlled slowing down of the sheets. By a controlled slowing down of the sheets is meant in this context a practically identical deceleration for each sheet from a starting speed to a determined reduced speed, allowing the sheets to be superimposed correctly in a stack, so that 'then it is enough to use simple means to align the sheets in the stack. Since the invention then provides for the use of a device for clamping the stack of aligned sheets, even when the stack is rotated from a flat position to an edge position, the correct alignment of the sheets in the stack is retained. On the whole, these measures allow first of all to establish and then to maintain a correct alignment of the sheets in the stack up to the casing station, which eliminates any cutting operation to adjust the edges of the finished product. .

In a preferred embodiment, an alignment of the sheets of the stack is provided not only during the formation of the latter, but also after its rotation into a position on edge. In fact, when transferring from the stacking station to the stack rotation device, the alignment of the sheets may be slightly disturbed. In addition, when the stack of sheets is in edge position, gravity can be exploited to improve alignment accuracy. In each case, the alignment is preferably carried out in two directions, that is to say in the frontal direction and in a direction transverse with respect to the direction of advancement of the sheets.

According to an important aspect of the invention, there is provided a device for slowing down sheets received individually and at rapid rates with a view to stacking them, in particular, but not exclusively, in a finishing machine of the type described above. This device comprises at least one pair of rollers between which each sheet is engaged upon receipt; one of the rollers is driven by a speed-controlled motor, in particular a stepping motor controlled so that the speed of rotation of the rollers corresponds to the speed of advancement of the sheets at the time of their engagement between the rollers, and is reduced to a fraction of this speed when the sheet is released from the rollers. Preferably, the stepping motor rotates at reduced speed while waiting for a sheet and is accelerated as soon as the arrival of a sheet is detected. In this case, a sheet detector being arranged upstream of the rollers and at a distance therefrom, the acceleration of the stepping motor is triggered when the front edge of a sheet is detected by the detector, and the phase sheet slowing is triggered upon detection of the passage of its rear edge on the detector. Thanks to this configuration, the stepping motor is not stressed when it is in standby mode, and the control of the stepping motor is greatly facilitated by the fact that the deceleration of the sheet is always triggered by the passage of its rear edge over the detector, the control therefore being independent of the length of the sheet.

To improve the accuracy of alignment of the cover relative to the sheets of the stack, the invention also proposes to provide a precise dosage of the quantity of glue used for each booklet or booklet. More specifically, the invention provides that the casing station comprises a rotating gluing roller partially immersed in a liquid adhesive and a scraper selectively controlled between a withdrawal position and an engagement position of the surface of the roller to accumulate a mass of glue which is presented to the edge of a pile of sheets when it passes over the edge of the rotating roller. The dosage of the adhesive mass is determined by the control of the scraper according to the movement of the pile and its thickness.

• La fig. 1 est une vue en plan schématique d'une forme de réalisation de la machine de finition;
• la fig. 2 est une vue en élévation schématique d'une station de prise en charge des feuilles, d'un dispositif de ralentissement contrôlé des feuilles, d'une station d'empilage et d'un dispositif de rotation d'une pile de feuilles;
• la fig. 2a est un diagramme illustrant la fonction de ralentissement;
• la fig. 3 est une vue schématique de détail du dispositif de ralentissement;
• la fig. 4 est une vue de détail d'un dispositif d'alignement des feuilles en pile;
• la fig. 5 est une vue schématique du dispositif de rotation d'une pile, d'un dispositif d'alignement par vibration et d'un dispositif d'encollage, précédant une station d'emboîtage de la machine; et
• la fig. 6 représente schématiquement les tranches encollées de deux piles de feuilles d'épaisseur différente.

Other details and particularities of the invention will emerge from the following description and the attached drawing, in which:

• Fig. 1 is a schematic plan view of an embodiment of the finishing machine;
• fig. 2 is a schematic elevational view of a sheet handling station, a controlled sheet slowing device, a stacking station and a device for rotating a stack of sheets;
• fig. 2a is a diagram illustrating the deceleration function;
• fig. 3 is a schematic detail view of the retarding device;
• fig. 4 is a detailed view of a device for aligning the sheets in a stack;
• fig. 5 is a schematic view of the stack rotation device, of a vibration alignment device and of a gluing device, preceding a casing station for the machine; and
• fig. 6 schematically represents the glued edges of two stacks of sheets of different thickness.

In the example described, the finishing machine according to the invention is attached to a printer 10 of a known type, capable of supplying more than one hundred printed pages per minute.

The printed sheets come out of this machine at a speed greater than 1 meter per second. The first station of the finishing machine is a station 12 for handling the sheets delivered by the printer 10. This station 12 is followed by a device 14 for slowing down the sheets received from the station 12. After controlled slowing of the sheets by device 14, the sheets are stacked in a flat stacking station 16. Each stack of sheets then passes through a transfer table 18 to a rotation device 20 which delivers each stack of sheets in edge position, after rotation of an angle of 90 ° around a horizontal axis, at a station of casing 22, oriented perpendicular to the alignment of the printer 10 and the units 12 to 20 of the finishing machine. This casing station will be described in more detail in the following description.

As can be seen more clearly from FIG. 2, the station 12 for taking care of the sheets delivered by the printer 10 comprises several pairs of transport rollers 30, 32 which rotate at a speed corresponding essentially to the speed of advancement of the sheets received from the printer 10. At the exit from this station 12, a detector 34 detects the passage of each sheet. More particularly, this detector 34 delivers a first signal when the front edge of a sheet is detected and a second signal when the rear edge of a sheet is detected. The sheets then pass through the controlled slowdown device 14. This device essentially consists of two pairs of rollers 36, 38 one of which, 38, is controlled in rotation by a stepping motor 40 through a toothed belt 42. As can be seen from the diagram in FIG. 2a, the motor step by step 40 drives the rollers 38 normally at a low speed v1, while waiting for a sheet. When at time t1 the detector 34 determines the passage of the front edge of a sheet, the motor 40 is accelerated to drive the rollers 38 at a speed v2 much higher, essentially corresponding to the leaf advance speed. In the diagram of FIG. 2a, this speed v2 is reached at time t2. The front edge of the sheet engages between the rollers 36, 38, and the sheet is advanced at speed v2 until time t3 when the passage of the rear edge of the sheet is determined by the detector 34. This event triggers a controlled slowdown of the step motor 40 until the rollers 38 rotate at the reduced speed v1. This speed v1 is low enough that the sheets, when released by the rollers 36, 38 at time t4, fall correctly and fall freely in the stacking station 16.

As shown in Figure 3, the rollers 36 are shaped to slightly deform the sheet F and thereby increase the rigidity during its passage through the slowing device to the stacking station. This action is generally called "tiling".

In the stacking station 16 shown in more detail in FIG. 4, the sheets F are stacked on a tray 44 provided with a fixed rear stop 46 and associated with a front jogging stop 48, actuated by an electromagnet 50 to align the sheets F against the stop 46 by a flapping movement towards this stop. Simultaneously, the sheets F are aligned by a lateral jogging stop 52, also actuated by an electromagnet (not shown). As also appears from FIG. 4, the front jogging stopper 48 is retractable to allow the stack of sheets F to advance when it is complete. The retraction of the front jogging stopper 48 is controlled through a connecting rod mechanism by a geared motor 54.

The transfer table 18 is provided with two parallel longitudinal slots allowing the passage of driving cleats 56 fixed to an endless belt 58. The endless belt 58 is dragged around two idler rollers 60 and 62 arranged below the transfer table 18. To advance a completed stack into the stacking station 16, one of the rollers 60, 62 is rotated to bring one of the tabs 56 against the rear edge of the stack of sheets F and push it in the direction of the rotation device 20 towards a front stop 65. The stack of sheets F therefore slides on the transfer table 18 as far as the front stop 65.

The rotation device 20 comprises a pair of jaws 64, 66 capable of engaging and clamping between them a stack of sheets F received from the stacking station 16. The jaws 64, 66 are mounted in a rotating unit, the axis of rotation A is horizontal and perpendicular to the direction of travel of the stack of sheets. As shown schematically in Figure 2, the rotation device 20 rotates each stack of sheets F by an angle of 90 ° to put it in a position on edge. In this position, the stack of sheets F is transferred to the casing station 22 where the stack of sheets F is supported by a second pair of jaws 68, 70. After engagement of the jaws 68, 70, the jaws 64, 66 can be loosened to allow advancement of the stack of sheets F in a direction perpendicular to the direction of advancement on the units 12 to 20 of the machine. To this end, the jaws 68, 70 are mounted on a mobile carriage of the casing station. These elements being known per se, they will neither be described nor shown in more detail.

The stack of sheets F is then advanced on a vibrating table 72 where the jaws 68, 70 are temporarily released. The vibrating table 72 is associated with a front stop 74 secured to the jaw 70 which is fixed on the transfer carriage, this stop 74 making it possible to correct the front alignment of the sheets. Since the sheets of the stack rest on edge on the vibrating table 72, their alignment is assisted by gravity.

After new alignment of the sheets F of the stack on the vibrating table 72, the stack is advanced, still in edge position, towards a gluing station 76, passing over a milling unit 78 which works the lower edge of the stack sheets F to facilitate the setting of the adhesive. As is well known, the gluing station 76 comprises a rotating roller 80 partially immersed in a bath of liquid glue 82 contained in a tank 84. A mobile scraper 86 is associated with the peripheral surface of the roller 80, also in known manner. oneself. However, according to a feature of the invention, the movements of the scraper 86 are controlled very precisely for a correct dosage of the amount of adhesive to be applied to the edge of the stack of sheets F when it passes over the turning roller 80. Since the glue intervenes in the volume of the back of a booklet or booklet with cover, its quantity has a significant influence on the alignment of the cover with respect to the sheets of the stack, after nesting of the latter in the cover.

When the edge of the scraper 86 is moved back from the periphery of the rotating roller 80, the adhesive forms a thin layer, but of constant thickness at the periphery of the roller. On the other hand, when the edge of the scraper 86 is engaged with the periphery of the roller 80, the adhesive accumulates at 88 in front of the scraper and is prevented from forming a layer at the periphery of the roller. When the scraper 86 is again removed, the glue 88 again forms a layer at the periphery of the roll 80. The quantity of glue applied to the edge of the stack of sheets F when it passes over the roll 80, is therefore determined by the duration of removal of the scraper 86. The duration of removal of the scraper 86 is in particular controlled as a function of the thickness of the stack of sheets. As for the control of the moment at which the scraper 86 is engaged, this is determined by the very movement of the stack when the latter is brought by the mobile carriage of the station, always clamped between the jaws 68, 70.

The result of this dosage of glue is illustrated in FIG. 6. It can be seen that the glue, represented by a hatching on the edge of the stack, is not abundant. It leaves one end of the wafer free, taking into account that after the application of the cover, the glue will have been spread to cover this area.

After fitting the glued stack into a cover and pressing the back of the booklet or booklet with another pair of jaws, the product is finished. Since the correct alignment of the sheets is preserved even up to the casing station, no cutting operation is necessary.

The nesting operation itself being well known per se, it will not be described in detail.

Claims (16)

1. A finishing machine for printed sheets individually delivered in rapid succession from a reproduction machine such as a printing press (10) or a copying machine for the production of a brochure, leaflet or booklet, the machine comprising the following in succession:

   a) a takeover station (12) for taking over delivered sheets;

   b) a device (14) for controlled retardation of the sheets received from said takeover station (12);

   c) a stacking station (16) for forming a horizontal stack of the retarded sheets;

   d) means (48, 52, 72, 74) for alignment of the sheets in said stack;

   e) a device (64, 66, 68, 70) for gripping said stack of aligned sheets;

   f) a pivoting device (20) for pivoting of said gripped stack from a horizontal position to an on-edge position; and

   g) a device (22) for glueing an edge of said stack and/or for encasing said stack in a cover.
2. The machine as claimed in claim 1, wherein said sheet alignment means comprise a lateral tapping abutment (52) for said stack in said stacking station (16).
3. The machine as claimed in claim 1 or claim 2, wherein said sheet alignment means comprise a front tapping abutment (48) for said stack in said stacking station (16).
4. The machine as claimed in any one of claims 1 to 3, wherein said sheet alignment means comprise a vibrating table (72) on which said stack rests in a released position after pivoting thereof into the on-edge position, and a front abutment (74).
5. The machine as claimed in any one of the preceding claims, wherein said gripping device comprises a first pair of jaws (64, 66) constituting a part of said pivoting device (20) and holding said stack gripped during the pivoting thereof, and a second pair of jaws (68, 70) taking over said stack after the pivoting thereof and before release thereof by the first pair of jaws.
6. The machine as claimed in claim 5, wherein said pivoting device (20) has a horizontal pivoting axis (A) athwart a direction of arrival of said stack of sheets and wherein said second pair of jaws (68, 70) constitutes part of a transfer device for transfer of said stack to said encasing station (22) in a direction athwart said direction of arrival of said stack.
7. The machine as claimed in any one of the preceding claims, wherein each stack of sheets is transferred from said stacking station (16) to said pivoting device (20) by sliding on a table (18) until arrival at said front abutment (65).
8. The machine as claimed in claim 7, wherein said table (18) has a pair of elongated parallel slots for the passage of dogs (56) for entrainment of said stack.
9. The machine as claimed in claims 3 and 8, wherein said front tapping abutment (48) is retractable to permit the passage of said stack on said table (18) from the stacking table (16) to said pivoting device (20).
10. The machine as claimed in any one of claims 1 to 9, wherein said device (14) for controlled retardation of sheets comprises at least one pair of rolls (36, 38) between which each sheet is engaged as from the reception thereof by the takeover station, one of said rolls (38) being driven by a controlled speed motor such as a stepper motor (40) operated in such a manner that said rolls (36, 38) have a speed of rotation which is equal to a supply speed of sheets at the instant of the engagement thereof between said rolls, and is reduced to a fraction (v1) of such speed (v2) at the instant of release of the sheet for the passage thereof to said stacking station (16) where said sheet is received while in free fall.
11. The machine as claimed in claim 10, wherein said stepper motor (40) rotates at a reduced speed (v1) in a sheet wait mode and is accelerated as from the moment of detection of the arrival of a sheet.
12. The machine as claimed in claim 11, wherein a sheet detector (34) is arranged between said takeover station (12) and said retarding device (14), wherein acceleration of the stepper motor (40) is started on detection of the leading edge of a sheet by said detector (34) and wherein a sheet retarding phase is started on the passage of the trailing edge of the sheet past said detector.
13. The machine as claimed in any one of claims 1 to 12, wherein said encasing station (22) comprises a rotating glue fountain roll (80) dipping partially into liquid glue (82) and a doctor blade (86) controlled selectively between a retracted position and a position of engagement at the surface of said roll (80) in order to accumulate a mass of glue (88), which is presented to an edge of a stack of sheets when same moves on edge over said roll (80), and wherein metering of said mass of glue is determined by operation of the doctor blade (86) as a function of the movement of said stack and the thickness thereof.
14. A device for the retardation of sheets received individually and at a rapid rate for stacking said sheets for a finishing machine as claimed in any one of the preceding claims, the device comprising at least one pair of rolls (36, 38) between which each sheet is engaged as from the moment of reception thereof, one of said rolls (38) being driven by a controlled speed motor such as a stepper motor (40) operated in such a manner that said rolls (36, 38) have a speed of rotation which is equal to a speed of supply of the sheets at the instant of engagement thereof between said rolls, and is reduced to a fraction of such speed at the instant of release of the sheet from said rolls.
15. The device as claimed in claim 14, wherein said stepper motor (40) rotates at a reduced speed in a sheet wait mode and is accelerated as soon as the arrival of a sheet is detected.
16. The device as claimed in claim 15, wherein said sheet detector (34) is placed upstream from said rolls (36, 38) and at a distance from the same, wherein acceleration of the stepper motor (40) is started on detection of the leading edge of a sheet by said detector (34) and wherein a sheet retarding phase is started on detection of passage of the trailing edge thereof by said detector (34).

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