EP1645531B1 - Apparatus and method for separating printing plates of a stack - Google Patents

Abstract

Device for isolating flat objects from a pile of pressure plates (4) by suction through suction element of lifting device (6) which is part of form element (7) that operates in a confined boundary (11). Suction is created in Form element by airflow (5) which has recess (13) and airducts (14). An independent claim is also made for the procedure for isolating pressure plates from a pile.

Description

The invention relates to a device for separating flat objects of different flexibility of a stack, preferably consisting of pressure plates and flexible intermediate layers, comprising at least one suction element for sucking the objects by means of a Saugluftströmung. Furthermore, the invention relates to a method for separating flat objects of different flexibility of a stack, preferably consisting of pressure plates and flexible intermediate layers of a stack, wherein the objects are sucked through at least one suction element.

For a single processing, flat objects stacked on top of each other and in particular delivered in such a stack must first be separated and then fed one at a time into a processing machine. In particular, printing plates must also be introduced individually for their exposure in a printing platesetter. This can be done manually. For reasons of labor economy, however, an automatic loading device (loader) is preferred, which can be preceded or predocked a printing platesetter. In the loading device, a stack of printing plates to be exposed is entered, and the loading device should have a separating device of the type mentioned, to allow automatic separation and loading.

However, the singulation process and charging process can be disturbed and interfere with subsequent processing or prevent multiple flat objects from sticking together, for example, two objects of equal rigidity, such as two printing plates, or different flexibility, such as a printing plate and an intermediate layer supporting the printing plate from a subsequent or previous one in the stack. For printing plates for separation as intermediate layers, for example Paper sheets used. Such intermediate layers can not be provided or inadvertently missing in a particular case or be present in two layers.

To separate the objects, these can each be lifted individually by means of a lifting device. This lifting device may, for example, comprise suction elements which suck in the objects and intermediate layers. This can lead to double sheets. With double bows refers to juxtaposing objects, such as printing plates and / or liners, so that several are raised by the lifting device. These double sheets must then be separated appropriately.

As intermediate layers, depending on the manufacturer, different materials can be used. Thus, it may happen that a porous material, e.g. porous paper is used as an intermediate layer. In this case, the suction elements of the lifting device set on an intermediate layer and the resulting vacuum also acts on the underlying object. In this case, the double sheets are held and sucked by the suction elements. Although these double sheets can be detected by sensors, but the separation is more complicated than if the double sheets, for example, by electrostatic forces together. In addition, there will be regular emergence of double sheets in these liners, whereby the separation process is at least hampered.

From the JP 54 11 58 71 A It is known to lift pieces of wood by means of suction elements. The suction elements can be moved in height. In the area of the suction elements projections are provided here, against which a wooden plate abuts and through which the wooden plate is deformed due to the further upward movement of the suction element. The deformation of the wood elements is done by a mechanical action on the wood panels by an upward and downward movement of otherwise rigid suction elements. If printing plates were separated with such a device, it would by the rigid up and down movement in conjunction with the projections can cause damage to the printing plates.

From the DE 26 59 421 A1 a similar device is known which attracts a film against a curved surface by an up and down movement of a suction element, which is rigid in itself. Again, the mechanical action on a printing plate damage to the printing plate could not be excluded. This is especially true in the event that only the pressure plate is raised for separation.

Also from the US-A-1 to 585.368 a device is known which draws a sheet by means of suction into a molding. Also, this device is not suitable for the separation of printing plates for the above-mentioned reasons, since even here to raise a printing plate and these would be mechanically impaired and this impairment could mean a false exposure by pressure points.

A deformation of the printing plates for dicing would also be in the use of a device according to the DE 198 54 826 A1 necessary. Here, a substantially triangular teat with three straight outer edges is proposed. The plates are also bent mechanically and held on protruding outer edges, so that they form an inner contact surface. Also, this mechanical impairment of printing plates should be avoided to avoid pressure exposures.

It is therefore the object of the invention to provide a device and a method of the type mentioned, by which the occurrence of double sheets is more often avoided and which increases the flexibility of the separating device by also stack can be separated with porous intermediate elements.

The object of the invention is achieved by the device by the features of claim 1.

This molding element may, for example, be a frame which encloses the suction element. It may also be a compact form, which surrounds the suction element and thus has a lower opening through which the suction element protrudes.

The suction element has a suction surface, which is bounded circumferentially by the so-called suction lip. Both the suction surface and the suction lip are both rubber-elastic. If a rigid object such as an inflexible pressure plate is sucked in, then they will form a substantially planar surface. If a less rigid object such as a flexible intermediate layer is sucked in by the at least one suction element, the suction surface will deform the intermediate layer such that it forms at least one air channel below it. This air can be supplied to the external air pressure, at least the intermediate layer can be easily solved by a pressure plate. Due to the limitations, it is made possible that procedurally the intermediate layers are deformed during suction by at least one suction element and form air channels below.

If the intermediate layer consists of a porous material and if there is another object underneath, then the further object can no longer be sucked in, since no vacuum can act on the further object due to the air channels or the deformed suction surface. In the case of porous liners, air will flow through the air channels. According to the invention, it is no longer possible to form double sheets.

According to the invention it is provided in a development that the boundaries enclose a lower surface formed by them, which is substantially parallel to the objects and is spaced from the suction surface of the suction element so that this suction surface is in the inactive state below the surface and the suction a flexible intermediate layer is deformed so that it is substantially above that of the boundaries shaped surface is located and air channels are formed below the liner.

Advantageously, only a flexible intermediate layer, such as e.g. Paper or porous paper will follow the deformed suction surface and be pulled over the lower surface of the boundary. A pressure plate is too inflexible for this. It can thus form air channels between the pressure plate and liner, air can flow and the vacuum no longer acts on the pressure plate, double sheets can be very effectively avoided.

In a particularly advantageous embodiment, it is provided device according to the fact that the boundaries have recesses or cuts, which differ in shape from the plane of the lower surface. As a result, the formation of the air ducts can be promoted better, they are no longer obstructed by the boundary itself in these areas of the limit. For example, if the boundary consists of a frame, then it may be provided that this frame has a rectangular shape, for example. It encloses the suction element. If the suction element now absorbs a flexible intermediate layer, the suction element and the suction surface will then deform such that the suction surface lies substantially above the frame. The flexible intermediate layer follows the deformed suction surface. For example, if at the same time a pressure plate was sucked in, since it was a porous intermediate layer, then the pressure plate is too rigid and will not deform flexibly, but will form a substantially planar plane with the lower surface of the frame. Between pressure plate and liner thus forms an air duct. Advantageously, this air duct can be increased thereby and continue to act between the surface between the pressure plate and intermediate layer when the frame, ie the boundary has recesses or cuts. For example, the frame can be made up of different elements separated from each other. The frame forms a lower plane, which acts as a boundary for a sucked pressure plate. This boundary may be designed in such a form that she leaves this level at one or more places. At these areas, there is no positive connection between the pressure plate and the boundary, here then an educated within the boundary between the pressure plate and intermediate layer air duct can extend outward. Any acting adhesion forces between the pressure plate and the intermediate layer can be advantageously counteracted. The intermediate layer can then better, even on the basis of the gravitational force of the pressure plate of this solve.

In a particularly advantageous further development, it is provided that the recesses or cuts are formed in the form of at least one groove. These are formal cuts in the boundary that act along one direction. Advantageously, these grooves are then provided in each mold element, which encloses a suction element. These grooves can be directionally matched to one another so that the formation of a continuous first air duct is supported by at least a plurality of mold elements. In this way, e.g. form an air channel over the entire width of the pressure plate or the intermediate layer and convey air of the outer air pressure between the intermediate layer and pressure plate.

The formation of this first long air duct may take a long time, it is therefore advantageously provided that in a development, the boundaries have more recesses or cuts in a different direction to the groove. This will form air channels in the form of folds in the intermediate layer, which form at least a second air duct.

Advantageously, the suction elements act on an edge surface of the flat objects or intermediate layers. The second air channels then quickly connect to the external air pressure. According to the invention, they are intended to run perpendicular to the printing plate edge, which runs parallel to the lifting device to which the suction elements belong. The distance So this edge is very low. Here air of the external air pressure between flat object and intermediate layer is passed, the effect of the vacuum is then no longer so good enough to suck the flat object, ie the pressure plate. By the grooves in the form of elements, the first air channel is formed, which is parallel to the one edge of the intermediate layers. Here, the adhesion between the flat object and the intermediate layer is removed over a large area and effectively counteracts suction of the flat object.

In the manner described, the formation of double sheets can be better avoided, and it is also possible to use porous paper as an intermediate layer.

If only one pressure plate is sucked in, then it behaves rigidly. A suction member will then form a substantially planar plane with the pressure plate in the area of the lower surface of the boundary. The pressure plate can therefore be easily lifted.

In a particularly advantageous development of the invention, it is provided that the suction element is deformable in the direction of the suction air flow. This will at least support that the suction surface in an activated state, i. with a sucked flexible object, behind the plane of the boundary is withdrawn.

The device described and the method described also counteracts the formation of double sheets consisting of two intermediate layers. The first intermediate layer is already sucked before it comes to a contact between the suction element and the stack. Due to the then occurring deformation of the suction surface and the suction lip, since the flexible intermediate layer is sucked into the area above the lower surface of the boundary, there is no effective positive connection between the suction element and another intermediate layer. A double sheet of two intermediate layers can be avoided at least better.

Fig. 1

Saugelemente einer Hebevorrichtung mit Formelementen,

Fig. 2

ein Saugelement aus Fig. 1 im inaktiven Zustand,

Fig. 3

ein verformtes Saugelement aus Fig. 1 im aktivierten Zustand,

Fig. 4

einen Querschnitt durch ein Saugelement beim Ansaugen einer Zwischenlage,

Fig. 5

einen Querschnitt eines Saugelements mit Luftkanal,

Fig. 6

einen Querschnitt eines Saugelements mit einem angesaugten flexiblen Objekt,

Fig. 7

einen Querschnitt eines Saugelements mit einem angesaugten starren Objekt.

An embodiment of the invention, from which further inventive features can be taken, but to which the invention is not limited in scope, is shown in the drawings. They show schematically:

Fig. 1

Suction elements of a lifting device with form elements,

Fig. 2

a suction element Fig. 1 in the inactive state,

Fig. 3

a deformed suction from Fig. 1 in the activated state,

Fig. 4

a cross section through a suction element when sucking an intermediate layer,

Fig. 5

a cross section of a Saugelements with air duct,

Fig. 6

a cross section of a suction element with a sucked flexible object,

Fig. 7

a cross section of a suction element with a sucked rigid object.

Fig. 1 schematically shows suction elements 6 of a not fully shown lifting device 1 with mold elements 7. By not shown lines 6 Saugluftströmung in the direction of arrows 5 is passed through the suction elements. In this way, porous intermediate layers 2 or printing plates 3, which lie on a printing plate stack 4 within a cassette 8 partially shown, are sucked in and then lifted by the lifting device 1. Non-porous intermediate layers 2 can also be used. Hereinafter, like reference numerals designate like elements.

As in Fig. 2 shown here, the mold element 7 consists of a compact form which surrounds a suction element 6. The molding element 7 has a boundary 11 as a lower edge surface, which is deformed by first recesses so that a continuous groove 12 forms on the underside of the molding element 7. This groove 12 is interrupted only where the mold element 7 surrounds the suction element 6. In this area, the mold element 7 has a second recess 13. This recess 13 extends perpendicular to the groove 12. The suction member 6 is in the form shown here a bellows suction. In the inactive state no object is sucked. The suction element 6 then has a suction surface 10 on which is conically shaped and is bounded below by a suction lip 9. The suction lip 9 lies below the plane which is enclosed by the boundary 11. Also in this state, suction air can be discharged in the direction of the arrow 5 through the suction element 6.

In Fig. 3 a deformed suction member 6 is shown in an activated state. In this state, it is when it sucks a flexible flat object, such as an intermediate layer 2. The suction member 6 and the suction lips 9 are deformed in the direction of the Saugluftströmung 5, that the suction surface 10 is withdrawn behind the plane, which is formed by the boundary 11.

Fig. 4 shows a cross section through a suction member 6 when sucking an intermediate layer 2. The suction member 6 is moved by the not fully illustrated lifting device 1 on the stack 4, but touches this not yet. The intermediate layer 2 has already been sucked in so far that it covers the suction surface 10. As a result, the suction element 6 is shortened and the suction lip 9 deformed so far that the suction surface 10 and the suction lip 9 within the groove 12, as in Fig. 2 and Fig. 3 has been represented behind the plane formed by the boundary 11. In this process step, only the intermediate layer 2 is sucked alone.

In Fig. 5 is the same suction element 6 as in Fig. 4 presented later in cross-section. It is here in contact with the stack 4, that is, it has been lowered by the lifting device 1 only partially shown. The intermediate layer 2 has been drawn so far behind the boundary 11, that under her a first air channel 14 has formed. This air channel 14 extends along the groove 12 and can thus between the individual suction elements 6, as in Fig. 1 are shown, are constructed. Along the air channel 14 can then air with external air pressure between the intermediate layer 2 and the subsequent object, here a pressure plate 3, arrive. The objects can thus be separated more easily, and even with porous intermediate layers 2, a double arc does not occur regularly since the following object is decoupled by the air channel 14 from the vacuum which acts under the suction surface 10.

In Fig. 6 is shown in a further cross-sectional view, as in this way, a porous intermediate layer 2 has been raised by the suction member 6 by means of the lifting device 1 is not fully shown. This intermediate layer 2 can then be separated in a suitable manner. For example, it can be transported on and disposed of.

In Fig. 7 a pressure plate 3 is shown, as it is lifted by a suction element 6 by means of the lifting device 1. The pressure plate 3 is a rigid object, which can not be deformed so far that it is pulled by the suction surface 10 behind the boundary 11. As a result of this interaction with the pressure plate 3, the suction surface 10 then forms a plane plane with the pressure plate 3 and can lift it with support by the lifting device 1 without problems. This printing plate 3 can then be fed to a further processing, for example in a platesetter.

As in the 4 and 5 A flexible intermediate layer 2 is drawn into the area behind the boundary 11. The intermediate layer 2 is deformed so that it lies in the groove 12 and here forms a first air channel 14, which extends over the entire width of a printing plate 3 and the intermediate layer 2. In the FIGS. 2 and 3 Furthermore, a recess 13 is shown. Also in this area, the boundary 11 is pierced so that the intermediate layer 2 can be deformed so that a second air duct, not shown here, can propagate out of the area within the molding element 7 to the outside. This second air duct runs essentially perpendicular to the first air duct 14. The suction elements 6 generally engage an outer region of the pressure plate 3 or the intermediate layer 2, so that the pressure region of the pressure plate 3 is not damaged. The distance between the suction element and the edge of the pressure plate 3 and the intermediate layer 2 is therefore not very large in the direction perpendicular to the first air duct 14 regularly. As a result of the formation of second air ducts perpendicular to the first air duct 14, first air with external air pressure can be rapidly supplied to the surfaces between successive objects such as printing plates and / or intermediate layers, whereby even a suction of a second object through a porous intermediate layer 2 is avoided , The adhesion between the successive objects is then further reduced by the first air channel 14 in the further process sequence. Here, a separation can be supported even better. This advantage is noticeable even with non-porous intermediate layers 2.

With the described device and the described method, whereby air channels are formed between successive objects of different flexibility or in each case successive objects with a high flexibility, as is usual with intermediate layers 2 of a printing plate stack 4, it is possible for one to use printing plates 3 and liners 2 by the supply of air with an external air pressure through an air duct 14 and second air channels perpendicular to this better to separate, and it is also possible to avoid the occurrence of double sheets in the use of porous liners 2. As a result, the separating device becomes more flexible, since printing plate stacks 4 are also separated may be, the intermediate layers 2 of porous material, in particular paper, have.

Claims (10)

1. Device for separating flat objects of varying flexibility in a stack, preferably consisting of printing plates and flexible interleaves, the device comprising at least one suction element (6) for sucking up an object by means of a suction air stream,
   characterized in
   that the at least one suction element (6)
   includes a suction surface (10) that is peripherally delimited by a suction lip (9), that the suction surface (10) and the suction lip (9) are both rubber-elastic,
   that the suction element (6) is essentially enclosed by at least one form element (7) having boundaries (11) that are spaced apart from the suction element (6),
   that, when a flexible interleaf (2) is sucked up, the suction surface (10) deforms the interleaf (2) in such a way that at least one air channel (14) is formed underneath the interleaf (2) due to the boundaries (1), and
   that, when a rigid object (3) such as an inflexible printing plate is sucked up, the suction surface (10) and the suction lip (9), together with the rigid object (3), form an essentially flat surface so that no flexible deformation of the rigid object (3) occurs.
2. Device according to Claim 1,
   characterized in
   that the boundaries (11) enclose a lower surface formed by the boundaries (11), which is essentially parallel to the objects (2, 3) and spaced apart from the suction surface (10) of the suction element (6) in such a way that, in the inactive condition, the suction surface (10) is located below the surface and, when a flexible object (2) is sucked up, the suction surface (10) is deformed in the direction of the suction-air stream in such a way that it is essentially withdrawn behind the plane formed by the boundaries (11) and that air channels (14) are formed underneath the flexible object (2).
3. Device according to Claim 1,
   characterized in
   that the boundaries (11) have recesses (12, 13) or notches that deviate in shape from the plane of the lower surface.
4. Device according to Claim 3,
   characterized in
   that first recesses (12, 13) or notches are formed in the shape of at least one groove (12).
5. Device according to Claim 4,
   characterized in
   that the boundaries (11) have further recesses (12, 13) or notches in a direction that is different from that of the groove (12) to form at least one second air channel.
6. Device according to at least one of Claims 1 to 5,
   characterized in
   that the suction element (6) is deformable in the direction of the suction-air stream (5) in such a way that the suction surface (10) is withdrawn behind the plane formed by the boundaries (11).
7. Device according to Claims 1 and 2,
   characterized in
   that, when a rigid object (3) is sucked up, the rigid object (3) forms an essentially flat plane with the lower surface of the boundaries (11).
8. Device according to Claims 2 and 7,
   characterized in
   that, when a flexible interleaf (2) is sucked up, the latter follows the deformed suction surface (10), and a rigid object (3) that has been sucked up at the same time is not deformed in a flexible way and thus forms an essentially flat plane with the lower surface of the boundaries (11) so that an air channel (14) forms between the flexible interleaf (2) and the rigid object (3) and the flexible interleaf (2) separates more easily from the rigid object (3).
9. Method of separating flat objects of varying flexibility in a stack preferably consisting of printing plates and flexible interleaves, wherein an object is sucked up by at least one suction element by means of a suction-air stream,
   characterized in
   that the at least one suction element (6) has a suction surface (10) that is peripherally delimited by a suction lip (9), that the suction surface (10) and the suction lip (9) are both rubber-elastic, that the suction element (6) is essentially enclosed by at least one form element (7) having boundaries (11) that are spaced apart from the suction element,
   that a flexible object (2) that is being sucked up is deformed by the suction surface (10) of the suction element (6) is deformed in such a way that an air channel (14) forms underneath the flexible object (2) due to the boundaries (11), and
   that, when a rigid object (3) such as a printing plate is being sucked up, a suction surface (10) and a suction lip (9) of the suction element (6), together with the rigid object (3), form an essentially flat surface so that no flexible deformation of the rigid object (3) occurs.
10. Method according to Claim 9,
    characterized in
    that air of the outer air pressure is fed in through the at least one air channel (14).

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