DE102004006233A1 - Device for selective transport of material to be printed, for printing machines has spring plate with friction wheel at each end, and adjusting element to bend plate to bring wheel into contact with conveyor - Google Patents

Abstract

The device has friction wheel (40,42), adjusting element (30) with drive (34) and regulator (70), and a driven conveyor element (50,52). A friction wheel is born turnable at each end of a spring plate (10). The spring plate is moved into a first active and a second passive bent condition by the adjusting element, so that the friction wheel is in active contact with the conveyor during active position. The adjusting element is formed by a cam plate with min and max. radius, and continuous transition between the two. The spring plate is of spring steel.

Description

The invention relates to a device for the optional transport of sheet-shaped substrates, according to the generic term of claim 1.

Transport devices for sheet-shaped substrates are in printing presses, especially digital printing presses and Copiers typically in large Number available. Especially with digital printing machines and copiers become frequent Used transport elements in the form of transport rollers or conveyor belts, which come into frictional contact with the sheet-like printing material and then push it in the transport direction. For this purpose, in the Rule pairs are used to align the sheet-like substrate not to be changed by transport. In As a rule, an attempt is made to make the sheet-shaped printing material exactly for this reason at all times on its transport path through the digital Hold the press / copier at at least two points. To ensure contact with the transport elements safely, are used as friction wheels in many digital printing machines / copiers pressing elements used that are related to the transport rollers and thereby a sufficiently large one Contact pressure between leaf-shaped Produce printing material and transport element.

However, the sheet-shaped substrate is in a digital printing machine / copier again and again, in which e.g. the leaf-shaped Substrate is directed against a stop or in contact with specially driven friction wheels comes who make the alignment. At this point the Transport elements are not in contact with the sheet-like printing material, otherwise the alignment cannot be carried out. In some digital printing machines / copiers are the sheet-shaped substrates from the transport elements to the alignment elements and then from taken over again. A transfer in some of these digital can be particularly space-saving Printing machines / copiers take place in which the transport elements get out of the way as soon as they get the sheet-like substrate passed to the alignment elements to have. As a rule, the effective relationship between is sufficient to interrupt the transport elements and the friction wheels in the Usually by lifting the friction wheels.

This is done in the prior art often solenoids used with lever systems, or motors with lever systems, for press the friction wheels Tension springs are often used on the transport elements. This solutions but usually have a very complex mechanism, i.e. it a lot of individual parts are required, which means an increased assembly effort and parts costs required. Moreover the tension springs counteract the lifting movement. Also go up the response times of such a lifting mechanism with its Complexity.

From the German patent specification DE 42 43 986 C2 A device is known in which the direction of travel of sheet-like printing materials is changed, in which transport elements which are attached to a rigid plate are brought into contact with the sheet-like printing materials by the action of an eccentric.

It would therefore be desirable if a device which carries out an optional transport of sheet-shaped printing materials manages with a small number of parts and a reliable, fast and easy to maintain mechanism of lifting the Offers counter rolls.

It is therefore the object of the invention another device for the optional transport of sheet-shaped substrates to disposal to put up with a reliable Separation of transport elements and counter rollers is possible.

This task is accomplished with the help of device according to the invention for transporting leaf-shaped Printing materials with the features mentioned in claim 1 solved. Further Features result from the subclaims. The invention also relates to also a method of releasing frictional contact with at least a friction-guided sheet-shaped printing materials with the steps disclosed in claim 12.

Accordingly, it is the device according to the invention a device for the optional transport of sheet-like printing materials, wherein the device has at least one friction wheel and one Casing, an actuator, a drive of the actuator, a controller the drive and at least one driven transport element, wherein at least one friction wheel is rotatable at the end of a spring plate is mounted, the spring plate in such a manner with respect to the housing and the actuator is attached so that the spring plate by means of the actuating element in a first active bending state and in one second passive bending state can be brought, in which active bending state, the at least one friction wheel in operative relationship stands with the transport element and in the passive bending state Not.

The provision of a spring plate enables a particularly simple construction. It is particularly advantageous that the movement of the at least one friction wheel takes place by means of an elastic deformation of a single component, both the upward and the downward movement. Since it is an elastic Deformation does not require any elaborate plain bearings or other mechanisms that are necessary when non-deformable components perform a movement, such as: levers, rigid plates, etc. In addition, the elastic deformation of the spring plate causes very little wear, unlike with moving, non-deformable parts that would show signs of fatigue much earlier.

Otherwise one understands in this Connects the term bending state as a state of deflection the spring plate in its elastic range, expressly included is the case in which the spring plate is flat and / or in is in an equilibrium bending state. A pre-bent, so with a radius spring plate is for example in one flat bending condition under tension, a spring plate not pre-bent not against it. In this context, an active relationship means that the at least one friction wheel has a sufficiently large force in the direction of the transport element applies so that between the transport element and a sheet-like printing material, the between the transport element and the at least one friction wheel should be transported, there is sufficient friction to to ensure transportation.

It is advantageous in the one bending state around an equilibrium bending state, in the other bending state, however, a deflected bending state. This automatically creates the necessary restoring forces to from the second bending state of the spring plate back to the first come back. It is at the discretion of the person skilled in the art which of these bending states is the corresponds to the active position of the friction wheel and which of the passive ones.

Another advantage that stands out the use of a spring plate reveals that most Parameters through the shape and storage of the spring plate in the housing are determinable. So lets e.g. by positioning the spring plate in the housing on the travel path of the friction wheels or the control element and the required forces that the control elements have to muster be taken. The bending stiffness of the spring plate determines below among other things, the speed at which the spring plate of the one bending state in the other due to the restoring force rebounds, provided the actuator leaves such a snap back to.

In an advantageous embodiment the inventive device is on each side of the spring plate at least one friction wheel rotatably mounted, particularly advantageous one pair of friction wheels each. In this way, the up and down movement of four friction wheels can be realized, while at the same time ensuring that the movement of all four friction wheels with each other simultaneously he follows. In another advantageous embodiment, only one is Reibräderpaar attached to one side of the spring plate.

In a further advantageous embodiment the device according to the invention the spring plate is preformed with a radius. The spring plate is in a relaxed, monostable bending state, when it bulges out with the preformed radius. Will the preformed spring plate such in the housing installed, so that the at least one friction wheel in operative relationship comes with the transport element, the can by the actuator at least one friction wheel can be lifted off, in which the adjusting element the spring plate e.g. in a substantially flat bending condition brings. Because of the restoring forces generated thereby and the monostable behavior the spring plate it is now only necessary the force that the actuator exerts on the spring plate to remove the spring plate in their original Position with a defined contact force between the at least one friction wheel and bring the transport element back.

In a further advantageous embodiment of the device according to the invention, the spring plate is in a bistable bending state in one of the bending states. A bistable state is obtained, for example, if a flat spring plate has a length L between two bearings, but the distance between the bearings is somewhat less than this length L. Then the spring plate bulges either downwards or upwards into one of the two stable bending states by. The spring plate can be pushed through its central position into the second stable state by a certain amount of force, which depends not least on the mounting. The advantage of bistable bending states is that the spring plate is in a stable equilibrium in the respective bistable state and therefore no energy has to be used to keep it in the bistable bending state. But with such a bistable spring plate there is also a third, unstable equilibrium state, namely when the spring plate is currently in the middle position and cannot decide in which of the bistable states it should move. It is then, while avoiding interference, no energy necessary to maintain the unstable bending state. Even a small force is sufficient to return the spring plate to the desired stable bending condition. However, it is not necessary for the invention that the two bending states of the spring plate, which bring about the active and the passive position of the at least one friction wheel, must be the bistable states of the spring plate. Rather, the spring plate is advantageously in the active position of the at least one friction wheel in one of the stable bending states of the bistable spring plate and in the passive position on of the at least one friction wheel in or near the unstable bending state of the bistable spring plate. This ensures, on the one hand, that the at least one friction wheel in the active position is kept in good working relationship with the transport element by the restoring force of the spring plate and, on the other hand, no or almost no energy is required to maintain the passive position in the passive position of the at least one friction wheel, but a small amount of force is sufficient to bring the at least one friction wheel back into the active position.

In a further advantageous embodiment the device according to the invention clamps a restoring force the spring plate in the passive bending state in the direction of the active one Bending state before, the restoring force is advantageously at least partially applied by the spring plate and / or advantageously the restoring force at least partially from additional ones Prestressing elements applied. With the prestressing elements it can be e.g. act on leaf springs, which a lateral deflection of the spring plate allow at least partially in the camps. As a result, the It is better to move the spring plate from one bending state to the other.

In a further advantageous embodiment the device according to the invention the control element is a cam, with the cam has at least a minimum and a maximum radius and the transition between the radii is continuous. In a special embodiment The minimum and one of such a cam alternate maximum radius in the circumferential direction every 90 °. The different radii cause the cam travel, the continuous change the radius allows the cam to roll gently on the spring plate and thus a continuous bending of the spring plate, which is preferable to a sudden bend in the spring plate.

In a further advantageous embodiment the device according to the invention the spring plate is made of spring steel, but is also a plastic, which has comparable elastic properties, conceivable. Likewise it is conceivable to generalize the device according to the invention another elastically deformable material from a shape condition by a suitable control element in a different shape and back bring to.

Preferred embodiments of the device according to the invention are detailed below with reference to the drawing described in more detail. In a schematic representation:

1 is a schematic isometric view of a first embodiment of the device according to the invention in the active bending state of the spring plate;

2 is a schematic side view of a first embodiment of the device according to the invention in the active bending state of the spring plate;

3 is a schematic isometric view of a first embodiment of the device according to the invention in the passive bending state of the spring plate;

4 is a schematic side view of a first embodiment of the device according to the invention in the passive bending state of the spring plate;

5 is a schematic isometric view of a second embodiment of the device according to the invention in the active bending state of the spring plate;

6 is a schematic side view of a second embodiment of the device according to the invention in the active bending state of the spring plate;

7 is a schematic isometric view of a second embodiment of the device according to the invention in the passive bending state of the spring plate;

8th is a schematic side view of a second embodiment of the device according to the invention in the passive bending state of the spring plate.

The 1 to 8th show the overall structure of the device 100 according to the invention. Further, generally known drive and / or guide means, cams and control elements required for operating the device are only shown schematically or are only described in general form. In a preferred embodiment, the device according to the invention is part of a digital printing press, a copier or a further processing device for sheet-like printing materials 1 ,

The pair of transport rollers 50 . 52 are on axially parallel transport roller shafts 51 . 53 rotatably mounted and driven by drive means, not shown, known to those skilled in the art. These transport rollers 50 . 52 are used in the above-mentioned device for transporting sheet-shaped printing materials 1 , To the sheet-shaped substrates 1 The transport rollers are also able to actually be transported 50 . 52 in active relationship with friction wheels 40 . 42 with a certain force on the transport rollers 50 . 52 press and thereby generate the required friction that the transport rollers 50 . 52 the transport of sheet-shaped substrates 1 enables them without slipping sideways or rubbing marks on the sheet-shaped substrates 1 arise.

As in 1 shown are the friction wheels 40 . 42 rotatable at the ends of a spring plate 10 attached. In addition there are the friction wheels 40 . 42 on axially parallel friction wheel shafts 41 . 43 attached, which have a slot in the middle, through which the end of the spring plate 10 forming spring plate tongue 11 submits. The friction wheel shafts 41 . 43 are mounted so that a vertical movement of the friction wheel shafts 41 . 43 and with it the friction wheels 40 . 42 is allowed. With the spring plate 10 is a plate made of spring steel, which in the 1 to 4 shown first embodiment of the device according to the invention with a radius R3 is preformed. The spring plate 10 is on both sides through a first housing wall 21 and a second housing wall parallel to it 22 stored. The storage of the spring plate 10 is designed so that the spring plate 10 from the in 1 and 2 shown active bending state, in which the friction wheels 40 . 42 in contact with the transport rollers 50 . 52 stand in a passive bending state, in which the friction wheels 40 . 42 not in contact with the transport rollers 50 . 52 stand as in the 3 and 4 shown. The contact forces of the friction wheels 40 . 42 on the transport rollers 50 . 52 is from the storage of the spring plate 10 in the housing walls 21 . 22 applied.

Above the center of the spring plate 10 is an actuator 30 , namely a cam 30 attached over a camshaft 32 one also on the case 20 attached drive 34 can be rotated. The drive is controlled by a controller known to those skilled in the art 70 controlled. The cam 30 has four 90 ° staggered cams 36 . 38 on, with the first and third cams 36 a first radius R1 and the second and fourth cams 38 have a second radius R2. The radius R1 is dimensioned such that the first or third cam 36 just in contact with the center of the spring plate 10 stands when it is in the active bending state. The cam disc changes its radius continuously between the smaller radius R1 and the larger radius R2.

To the friction wheels 40 . 42 to be lifted off the transport rollers, as in the 3 and 4 shown, the cam disc 30 rotates 90 ° and thereby bends by means of the second cam 38 the spring plate 10 continuously in a substantially flat bending condition. The cam 30 initially remains in this angular position and acts on the cam 38 the restoring force of the spring plate 10 opposite. The over the housing walls 21 . 22 protruding ends of the spring plate 10 follow the bending state of the spring plate 10 and thereby lift the friction wheels 40 . 42 from the transport rollers 50 . 52 off, leaving a gap that is labeled with the reference number 60 is marked, arises. If the cam disc is turned another 90 °, the spring plate 10 continuously returned to their original active bending state and the friction wheels 40 . 42 come into contact with the transport rollers again 50 . 52 , if not just a sheet-shaped printing material 1 is pinched in between.

The in the 5 to 8th shown second embodiment of the device according to the invention 100 has an almost identical structure to the first embodiment of the device according to the invention 100 , however, this is a flat spring plate 10 , instead of the spring plate pre-bent with a radius R3 10 from the first embodiment.

Around the flat spring plate 10 to give the desired deflection in the active bending state are on the outside on the housing sides 21 . 22 leaf springs 24 . 26 attached the spring plate in the spring plate level 10 compress and thereby generate the desired deflection. The spring plate 10 is in the in the 5 and 6 shown bending state in a stable balance between the restoring force of the spring plate, and the lateral leaf springs 24 . 26 , The side leaf springs 24 . 26 are just dimensioned so that they are in this state on the housing walls 21 . 22 invest. The spring plate 10 is in a bistable state in this state.

The spring plate 10 strikes the tongues of the leaf springs 24 . 26 on. Now the cam disc 30 The spring plate is turned by 90 ° 10 brought into a flat, passive bending state in which the friction wheels 40 . 42 again from the transport rollers 50 . 52 take off. To shorten the arc length of the spring plate 10 between the housing walls 21 . 22 to compensate for this change in the bending state pushes the spring plate 10 the leaf springs 24 . 26 something outward and tense, compare 8th , The spring plate 10 is now in an unstable equilibrium between the two possible bistable equilibrium positions. In the direction of the surface normal of the spring plate 10 no forces act in this state, however, the spring plate is prevented, for example, by a stop, not shown 10 flips down into the second, undesired bending state, because the spring plate 10 thus out of the sphere of action of the cam 30 would arrive. Will the spring plate 10 slightly deflected in this state, the restoring forces of the side leaf springs result 24 . 26 that the spring plate 10 following the cam moves back to its active bending state. In the passive bending state of the second embodiment, the spring plate is advantageously not moved completely into the unstable state, so that the restoring force of the leaf springs 24 . 26 the spring plate at least with a small force against the cam 30 press so that the return path is in the active bending state of the spring plate 10 is definitely guaranteed.

In an alternative embodiment, the control element 30 around a solenoid, not shown, with a plunger. Another, alternative embodiment is only half-sided stalten, so only on one side of the spring plate 10 friction wheels 40 on, the other end of the spring plate 10 is stored accordingly.

The device according to the invention disclosed here and the method according to the invention finds particular application in a digital printing press, a Copier or other further processing device for sheet-like printing materials, but it can also be used in other devices those individual, essentially flat, materials under frictional contact can be transported with transport elements, and the transport device should be switched on and off in which the friction between the Transport elements and the material to be transported is reduced.

1

sheet-shaped printing material

10

spring plate

11

Spring plate tongue

20

casing

21

first housing wall

22

second housing wall

24

first leaf spring

26

second leaf spring

30

cam

32

Cam shaft

34

drive

36

first cam

38

second cam

40

first friction wheel

41

first Reibradwelle

42

second friction wheel

43

second Reibradwelle

50

first transport roller

51

first Transport roller shaft

52

second transport roller

53

second Transport roller shaft

60

gap

70

control

100

device according to the invention

R1

first Radius of the control element

R2

second Radius of the control element

R3

radius the spring plate

Claims (10)

Device for the optional transport of sheet-like printing materials ( 1 ), the device ( 100 ) at least one friction wheel ( 40 ; 42 ) and a housing ( 20 . 21 . 22 ), an actuator ( 30 ), a drive ( 34 ) of the control element ( 30 ), a controller ( 70 ) of the drive ( 34 ) and at least one driven transport element ( 50 . 52 ), characterized in that at least one friction wheel ( 40 . 42 ) at the end of a spring plate ( 10 ) is rotatably mounted, the spring plate ( 10 ) in relation to the housing ( 20 . 21 . 22 ) and the control element ( 30 ) is attached so that the spring plate ( 10 ) by means of the control element ( 30 ) can be brought into a first active bending state and into a second passive bending state, the at least one friction wheel ( 40 . 42 ) in active relationship with the transport element ( 50 . 52 ) stands and not in the passive bending state. Device according to claim 1, characterized in that on each side of the spring plate ( 10 ) at least one friction wheel ( 40 . 42 ) is rotatably mounted. Device according to one of claims 1 to 2, characterized in that the spring plate ( 10 ) is preformed with a radius (R3). Device according to one of claims 1 to 3, characterized in that the spring plate ( 10 ) is in a bistable bending state in one of the bending states. Device according to one of claims 1 to 4, characterized in that a restoring force the spring plate ( 10 ) in the passive bending state in the direction of the active bending state. Apparatus according to claim 5, characterized in that the restoring force at least partially from the spring plate ( 10 ) is applied. Device according to one of claims 5 to 6, characterized in that the restoring force at least partially from biasing elements ( 24 . 26 ) is applied. Device according to one of claims 1 to 7, characterized in that the adjusting element ( 30 ) a cam ( 30 ) which has at least a minimum and a maximum radius (R1, R2) and the transition between the radii (R1, R2) is continuous. Device according to one of claims 1 to 8, characterized in that the spring plate ( 10 ) around a plate ( 10 ) is made of spring steel. Method for releasing in contact with at least one friction wheel ( 40 . 42 ) sheet-shaped substrates ( 1 ) with the following steps: a) storing at least one friction wheel ( 40 . 42 ) rotatable on at least one end of a spring plate which is in an active bending state ( 10 ), so that at least one friction wheel ( 40 . 42 ) in active relationship with a transport element ( 50 . 52 ) of the sheet-like printing material ( 1 ) stands. b) provision of at least one control element ( 30 ) with a suitable drive ( 34 ) and control ( 70 ), so that the control element ( 30 ) in active relationship with the spring plate ( 10 ) can come, c) generating a passive bending state of the spring plate ( 10 ), whereby the at least one friction wheel ( 40 . 42 ) the operative relationship to the transport element ( 50 . 52 ) loses.