EP0739721A1 - Device for treating metallized, used webs in a machine for transferring metallized images on flat elements - Google Patents

Abstract

The machine for processing used tapes from a printing machine comprises an accumulation reservoir (30) receiving the used tapes (3,5) in its upper part. The tapes are delivered by a supply mechanism (26,62,40) and pass through a grinding mechanism (50). The grinding mechanism (50) automatically starts running intermittently under the command of a control device (60). The output of the grinder (50) opens into a waste transport container (90) carrying waste through an evacuation channel. Inside the upper part of the reservoir there is a deflector plate (34) mounted obliquely to ensure that the used tapes go into the centre of the reservoir. A fan (38) may provide a thin film of air on the surface of the deflector. The reservoir may be conical towards the bottom, directing tape towards the grinding position.

Description

The invention relates to a device for processing used metallized strips in a machine for transferring metallized images onto plate elements, such as sheets of cardboard, paper, plastic, etc. The invention relates more particularly to a device used in a platen press comprising a fixed upper bed base and a movable lower bed base, bed bases between which the cardboard sheet is brought, for printing thereon, according to given patterns, of a metallized film from a conductive strip between this sheet and one of the box springs.

Such a platen press usually comprises first of all an introduction station in which a stack of sheets is installed, each sheet being successively removed from the top of the stack to be sent to a margin table. On this table, each sheet is placed in position against front and side cleats before being gripped at its front edge by a series of clamps mounted along a transverse bar, each end of which is attached to a train of side chains taking the bar, and therefore the sheet, to the following treatment stations. The treatment station (s) may be a transfer station for the metallized film, possibly combined with cutting tools, followed by a waste ejection station. These processing stations are finally followed by a receiving station in which each sheet released by the clamps falls squarely on top of a pile accumulating on an output pallet.

An independent device for transporting parallel metallized strips successively comprises a support for strip supply reels, means for intermittently unwinding and advancing the strips, guide means for guiding these strips parallel to the direction of scrolling of the sheets between the plates, then guide in clearance around one of the plates of the press, a tensioning mechanism to tension these bands at least along their trajectory between the plates, and a device for discharging the bands used outside the machine, usually through a side window.

The metallized bands having an identical intermittent running speed pass through the same means of advancement and unwinding, while the bands having a different speed pass through second or even third means of unwinding and advancing split, the tensioning mechanism being adjusted in this case according to the highest speed.

The tensioning mechanism usually consists of a tension roller driven either continuously at a speed substantially higher than the speed of advance of the metallized strip, or of a tension roller sequentially driven at a speed substantially higher than the speed of advance of the metallic strip. In both cases, the strip is pinched against this roller by at least one pressure roller whose pressure is adjustable. Leaving this roller, the strip makes a right angle around a deflection bar in the direction of a side window of the frame of the machine where it is ejected by two rotating brushes to fall into a bin or a bag. Preferably, knives located close to the tension roller cut the strip longitudinally into several strips.

In use, however, it turns out that this waste of strips being only cut longitudinally, they fill the container or receiving bag too quickly which must then be replaced by the operator very frequently. In addition, these bags form bulky bulky bales to transport.

The object of the present invention is a waste treatment device, consisting of used strips, cut longitudinally and possibly arriving with different speeds, this device making it possible to reduce as much as possible the volume of this waste to evacuate it in more compact bags, or even by a pipe. The design of this device must however remain simple for better reliability of operation over time and a reasonable cost of production.

These goals are achieved by a processing device in that it comprises an accumulation tank receiving in its upper part the used strips brought by supply means, and supplemented in its lower part with a crusher automatically put in works intermittently under the control of a control device, the output of the crusher giving into a waste transport container. Preferably, the shredder consists of two parallel cylinders located opposite and carrying knives interpenetrating to cut the waste transversely and longitudinally.

Thus, the used strips are cut into waste of small dimensions, such as confetti, which then fill the container in a much denser manner. The interval between two exchanges of containers then becomes longer, which frees the operator accordingly.

According to a preferred embodiment, the reservoir comprises, in its upper part, a downward oblique deflector deflecting the initial fall of the used strips towards the middle of the reservoir. If desired, a blower forms an air film on this deflector to eliminate any friction and thus avoid any accumulation of tape at this level. Thus, the accumulation of the used strips in the tank takes place in a very homogeneous manner, which eliminates any risk of premature backflow.

According to a preferred embodiment, a plurality of knives, each coated with a block of a flexible material, such as a rubber foam, is installed either at the level of the means for feeding the used strips, for example a pair of parallel brushes opposite, in the upper part of the tank, ie at the lower end of the deflector. So, if a belt driven by the grinder tightens, normally that whose speed is the lowest, it compresses the block of foam and impaled on one of the knives which cut it instantly. Thus, no overvoltage can be passed on in the path upstream from the strip to the supply coil, and distort the register of this strip under the plate.

Preferably, the lower part of the accumulation tank is tapered downwards towards the inlet of the mill, so that the latter is almost always in contact with the used belt. If desired, an insertion pestle driven by an actuator, that is to say an electric, pneumatic or hydraulic cylinder, and oriented towards the inlet of the mill, is installed in the upper part of the conical part of the tank. in order to reset it if it runs idle.

Advantageously, the control device triggers the crusher after accumulation of a predetermined length of used strips, as read by a counting roller which may belong to the means for feeding the strip into the upper part of the tank, this crusher being placed in works for a predetermined period corresponding to the emptying of most of the tank. This process is particularly simple and effective.

Alternatively, the control device comprises a sensor for filling the tank to a predetermined maximum level, the tilting of which activates the crusher, as well as a sensor for emptying the tank to a predetermined minimum level, the tilting of which causes the grinder to stop. Such a sensor can comprise, for example, a plurality of photoelectric cells whose reading of a light beam must be interrupted for a minimum delay for a majority of them during a switchover.

Advantageously, the crusher is driven by an electric motor provided with a device for measuring overcurrent during an overload due to too great accumulation of bands or the presence of a hard object, this device then causing a drive. momentary grinder reverse.

The shredder is usefully connected to the transport container by a pneumatic line. The waste being reduced to confetti, they are then completely transportable to another point of the workshop by simple breath of air generated by a fan, place where the transport container is better accessible and movable. An audible or luminous warning device is then provided for the complete filling of the container.

The invention will be better understood from the study of an embodiment taken on a non-limiting basis and illustrated diagrammatically from the side in the left part of the appended figure, where is also represented in the right part, front view, the press. plate of an associated printing machine.

As shown, the press comprises an upper horizontal plate 10 fixed in the frame of the machine and a parallel underlying plate 12 movable vertically. For this, this lower plate 12 is supported by a device 14 composed of a pair of parallel kneepads facing each other whose median axes are connected by one or more horizontal connecting rods to a rotary crankshaft installed between these knee pads. Thus, the lower plate 12 presses upwards each of the sheets 1 brought sequentially according to a horizontal displacement by a bar of pliers not illustrated, and this against plates fixed on a board secured to the lower face of the fixed upper plate 10.

More particularly, in the context of this invention, provision is made to insert between the sheet 1 and the printing plates of the upper plate 10 an inking strip 3 or a metallized strip for depositing, on this sheet 1, d 'an image in a remarkable color, in particular with metallic reflection. For this, intermittent unwinding and advancing means not illustrated sequentially bring this strip 3 under the plate, this strip being taken up on the other side by guide rollers upwards in the direction of a tension roller 20 located in the part upper part of the machine usually above the press, for example, close to its front edge. This strip 3 is pressed against the tensioning roller 20 by rear pressure rollers 22. The speed of rotation of this tensioning roller 20 is greater than the running speed of the strips 3 as imposed by the intermittent unwinding means, so that to induce a necessary and sufficient tension to correctly maintain this strip in the parallel plane of the press.

At the exit from this tensioning roller 20, the bands are oriented at right angles by deflection rollers 26 to a side exit window of the machine frame, where they are guided downwards by a roller 62 before being driven ejected by a pair of drive brushes 40. Knives 24 installed either at the tension roller 20 or at the return rollers 26, make one or more longitudinal cuts transforming the used metal strips 3 into strips.

According to the invention, these strips of used strips 7 are not directly introduced into a transport container 90 but fall first into an accumulation tank 30.

As illustrated, the drive brushes 40 project the strips 7 towards a downward oblique deflector 34 initially orienting these strips in the vertical median plane of the tank 30. To avoid any untimely accumulation of strips 7 from the inlet of the tank 30, a blower 38 forms an air stream on the oblique upper face of this deflector 34. The relatively light strips 7 then hardly touch the deflector 34 which cannot catch and hold them by friction. As illustrated, the strips 7 then accumulate in superimposed loops of width more or less equal to that of the reservoir.

More particularly, according to the invention, the lower part 32 of the reservoir 30 is oblique downwards as seen in cross section. The lower end of this conical part constitutes a substantially rectangular opening giving onto a grinder 50, in the occurrence a chopper formed of two parallel cylinders arranged opposite and carrying on their periphery a network of knives interpenetrating. The geometry of this network of knives is such that this crusher can shred the strips 7 longitudinally and transversely to reduce them to waste 9 of small dimensions of the order of a few square centimeters. To this end, these rollers are driven in the opposite direction of rotation by an electric motor 52: the left roller in the clockwise direction and the right roller in the opposite direction so as to project the waste 9 towards the bottom in an outlet pipe 38.

This waste 9 can fall directly into a transport container 90 placed immediately under the tank 30. Alternatively, this waste 9 is sucked into a discharge duct 39 in which there is a current of air generated by fans, this duct taking this waste in another place more suitable for the installation and handling of the transport container 90.

To be effective, the knife rolls of the crusher 50 must rotate at a minimum speed fast enough causing them to cut the strips 7 much faster than they accumulate in the tank 30. For this purpose, this crusher 50 is implemented only intermittently, just when necessary, by control means 60. These control means can be computer and electronic means comprising a control unit, implementing a program prerecorded in memory and modified by entering additional data using a keyboard in the light of momentary results appearing on the screen.

According to a first method, the control means receive counting pulses emitted during the rotation of a counting roller 62 which may be one of the guide rollers preceding the drive brushes 40. Thus, when the passage of a sufficient amount of straps to fill the major part of the tank 30 has been deducted, the control means 60 engage the electric motor 52 of the crusher 50 during a predetermined delay corresponding substantially to the time required for this shredder to destroy this major part of strips 7 present in the tank 30. This delay can be adjusted by the operator by entering a new value on the keyboard.

As an alternative, two level detectors are installed in the tank 30: a maximum level detector 64 and a minimum level detector 64 ′, each connected to an input card of the control means 60. These detectors can, for example, be a plurality of photoelectric cells receiving a beam of light from a light source situated against the opposite wall. When the maximum level is actually reached, then only a majority of cells no longer receive light beams for a predetermined interval at least of the order of a second. The control means 60 then trigger the crusher 50 which they stop as soon as the lower detector 64 'switches over in turn.

The conical shape of the lower part 32 of the tank 30 means that the crusher 50 is normally always in contact with one or more strips 7 allowing it, as for spaghetti, to drive the following. If desired, a pestle 54 can be installed in this conical lower part 32 of the tank in the form of an electric, pneumatic or hydraulic jack, the rod of which can extend downwards towards the mill and the end of which is provided with a pusher member such as a ball or a rectangular plate. Thus, in the unlikely event that the crusher 50 turns to empty, it is possible to use this pestle 54 to push the strips 7 into the crusher and reset it.

The speed of movement of the metal strips 3 in the plate depends directly on the extent of the patterns to be printed successively. In other words, the strip is advanced by an amount just necessary to cover the length of the pattern, thus optimizing the consumption of this strip. If this length is small, the running speed, therefore the speed of accumulation in the reservoir of the corresponding band, is also low. During an operation of the crusher 50, one of the strips can find itself completely shredded very quickly and suddenly tighten as illustrated by the strap 7 '.

For this, there is provided at the start or at the end of the deflection path imposed by the deflector 34 a device for hidden knives. This device comprises a plurality of knives 42, 42 'distributed at regular intervals along a crosspiece. The knife blades are wrapped in a block of elastic flexible material 40, 44 ′ which projects beyond the point of the knives. This material can be a rubber foam or elastic plastic material. In this way, a strap brought by the drive brushes 40 under zero tension slides without further against the flexible blocks 40, 44 '. By cons, as soon as a strap 7 'stiffens, it compresses either the upper block 44 or the lower block 44' which, by retracting, reveals the tip of one of the knives 42, 42 'which tears and cuts instantly this strap. No overvoltage can therefore be passed upstream, in particular at the tension roller 20.

Many improvements can be made to this device for processing used strips within the scope of the claims.

Claims (9)

Device for processing used strips in a printing machine for plate elements, characterized in that it comprises an accumulation tank (30) receiving in its upper part the used strips (3, 5) provided by means supply (26, 62, 40), and completed in its lower part with a crusher (50) automatically started intermittently under the control of a control device (60), the outlet (38) of the crusher (50) giving into a container (90) for transporting waste (9). Device according to claim 1, characterized in that the tank (50) comprises, in its upper part, a deflector (34) oblique downwards deflecting the initial fall of the used strips (5, 7) towards the middle of the tank. Device according to claim 2, characterized in that a blower (38) forms an air film on the deflector (34). Device according to claim 2, characterized in that a plurality of knives (42), each coated with a block of flexible material (44), is installed either at the level of the feeding means (40) of the used strips (5) in the upper part of the tank (30), ie at the lower end of the deflector (34). Device according to one of the preceding claims, characterized in that the lower part (32) of the accumulation tank (30) is tapered downwards, oriented towards the inlet of the mill (50). Device according to claim 5, characterized in that an insertion pestle (54) driven by an actuator, and oriented towards the inlet of the mill (50), is installed in the upper part of the conical part (32 ) of the reservoir (30). Device according to one of the preceding claims, characterized in that the control device (60) starts the crusher (50) after accumulation of a predetermined length of used strips (7) as read by a counting roller (62) belonging to the means (26, 62, 40) for feeding the strip into the upper part of the tank (30), this mill (50) being used for a predetermined period corresponding to the emptying of the major part of the tank. Device according to claim 7, characterized in that the crusher (50) is driven by an electric motor (52) provided with a device for measuring over-intensity during an overload, this device then causing a momentary drive of the crusher reverse. Device according to claim 1, characterized in that the crusher (50) is connected to the waste transport container (90) (9) by a pneumatic line (39).

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