JPH08113406A - Sheet paper damping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To brake printed paper sheets without causing ink stains on them. SOLUTION: A braking strap 3 has at least one discrete suction device 8 operating on a selective partial region (a sheet rear edge 11) of a sheet 2 to be braked white circulating together therewith and part of the braking strap 3 facing the remaining region of the sheet 2 has at least no active suction device 6.

Description

Detailed Description of the Invention

[0001]

The present invention comprises at least one braking strap with attached suction device,
The invention relates to a device for a sheet braking device, in particular a sheet ejection device of a sheet-fed printing press, in which the braking strap is connected to a drive device which produces an uneven circulation speed.

[0002]

2. Description of the Related Art A device having such characteristics has been disclosed in publications.
Known from DE 41 19 511 A1. This known braking strap has a breathable circulating running belt with an attached suction box. The belt is guided around three guide rollers, preferably the middle roller is connected to the drive motor. The drive motor is controlled non-uniformly in order to brake and re-accelerate the circulation speed of the belt, which braking and acceleration takes place at the timing of the transport of the sheet to be braked. This known device is used for braking unprinted sheets, in particular sheets delivered from a crosscutting machine.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide ink-free braking of printed sheets, whether for front-side or double-sided printing. To provide a device.

[0004]

SUMMARY OF THE INVENTION According to the invention, the object is to provide at least one discrete suction, with which a braking strap circulates and acts on a selectable partial area of the sheet to be braked. Have a device,
The part of the braking strap that faces the rest of the paper is
At least this is achieved by not having an active suction device.

[0005]

By virtue of such a construction, the suction device is aimed at and works in combination with only a specifically selected partial area of the paper sheet to be braked, which partial area is used. It is preferably the unprinted trailing edge of the leaf. This ensures that the then remaining areas of the paper format are guided without contact. In other words, in some cases, the printing ink there does not cause ink stains. The suction device is centrally located at one or more points on the braking strap, and the remaining area of the braking strap has no suction device or no active suction device so that the remaining area It is ensured that the area of the leaf facing the sheet cannot be aspirated and thus cannot be touched by anything. The braking strap is, in each case, such that a selected partial area of the sheet to be braked comes into contact with the suction device,
It is controlled by the drive unit.

In particular, it is stated that the suction device has at least one suction opening partially formed on the braking strap. However, it is also conceivable, for example, that a row of suction openings is formed on the braking strap in a direction perpendicular to the direction of its circular movement. In addition, for each of the sheets to be braked, a plurality of such or differently formed belts do not circulate completely once, but a fraction thereof. It is also conceivable that the suction devices in question are distributed at a distance from one another over the length of the braking strap.

The suction device preferably has at least one suction element, in particular a suction cam or a suction rod, which projects outward from the contour of the circular movement of the braking strap. Here, the suction cam means, for example, an outer contour of the braking belt that has a suction opening that projects from the outer surface of the braking belt and communicates with the suction box, and that exerts a suction action on the sheet. Such a configuration ensures that the paper sheet moved on the suction device keeps an appropriate distance to the contour of the circular movement, due to the suction element protruding outside the contour of the circular movement, and thus the contact and thus the ink. It is advantageous in that dirt is reliably prevented. If the suction element is constructed as a suction rod, it extends in a direction perpendicular to the direction of circular movement of the braking strap, on the upper side of which one suction opening or a plurality of suction openings (preferably in a row) have.

According to one development of the invention, during suction of the trailing edge of the sheet, the drive transmits to the braking strap a velocity corresponding to the velocity of the sheet. As a result, the suction device and the trailing edge of the sheet travel at the same speed during suction, that is, in synchronization with each other. Furthermore, after the suction of the trailing edge of the sheet, the drive device slows down the circulation speed of the braking strap. Thereby, a damage-free drop of the paper on the paper pile can be performed.

In particular, it is assumed that the drive device is an electric servomotor. There, it is desirable to provide a servomotor that is extremely strong and that enables rapid acceleration and braking. It suffices if such a motor drives a corresponding guide roller of the braking strap, for example directly, that is, not via a gear.

According to one development of the invention, the braking strap is provided with a floating guide for the sheets. The leaf is guided without contact by its floating guide to the braking strap and is then sucked and braked at the trailing edge of the leaf by a suction device. There, it is preferably the gripper device that is responsible for the transport of the leaf, which gripper opens as soon as the trailing edge of the leaf is sucked.

Preferably, a plurality of floating guide areas of the floating guide device are connected to the braking strap on the front side in the direction of the sheet movement. At least one floating guide area of the floating guide device is preferably arranged laterally of the braking strap. Here, the lateral direction is a direction extending at a right angle to the paper sheet movement direction.

In particular, a plurality of braking straps may be laterally spaced from one another. As a result, these braking straps form a row of braking straps that extend over the width of the sheet, whereby
The paper sheet will be acted upon by a plurality of braking straps at its trailing edge. In particular, there may be one floating guide area as described above between any two braking straps.

According to one preferred embodiment of the invention, the floating guide associated with the braking strap has a number of air nozzles from which an air stream emerges, which it carries. It is supposed to create an air layer, which makes it possible to guide sheets without contact. There, the air flow may be directed in the first region in a direction opposite to the paper movement direction. Additionally, the air flow may be directed in the direction of the leaf movement in the second region. An air outflow zone may be formed between the above two areas and is preferred. This air outflow zone is formed, for example, by a gap extending over the width of the paper transport path, whereby the flow of carrier air coming from both areas moves into and through it. Be extracted.

Finally, the first area is ahead of the second area when viewed in the paper sheet movement direction. Further, the braking belt forming the braking strap is a servo motor (M).
Is preferably operatively connected in a shape-dependent manner (eg engagement of gear and toothed belt).

[0015]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows a braking device 1 for a paper sheet 2,
In this device, each sheet of paper 2 is first moved over the device 1 by a gripping device 9 by a fixed distance, and then, as will be described later, the gripping device 9
Released from. The braking device 1 includes two guide rollers 4
Includes a braking strap 3 wrapped around the. At least one of the guide rollers 4 is operatively connected to a drive in the form of a servomotor M. The braking strap 3 is under the action of the drive device the arrow 6
In the direction of, a braking belt 5 (suction belt) that circulates at a non-uniform circulation speed.
Between the guide rollers 4 is a suction box 7 connected to a negative pressure source (not shown).

The braking belt 5 has a discrete suction device 8 which carries out a circulating movement with it. Discrete means that the suction device 8 is aimed at a specific location on the braking belt 5 and that at least some areas of the braking strap 3 formed by the braking belt 5 completely displace the suction device 8. It means that they do not have or have no active suction device 8. Inactive means that the sheet 2 above the separate moving device 1 is not sucked. When the paper sheet 2 is moved over the braking device 1 in the direction of the arrow 10 by the gripper device 9 that grasps the front edge of the paper sheet 2, synchronization with the suction device 8 is performed so that the trailing edge 11 of the paper sheet is sucked. Will occur. At the moment of suction, the suction device 8 and the sheet 2 are moving at the same speed. That is, there is no relative speed between the sheet 2 and the braking belt 5 in the direction of the arrow 10. As soon as the suction is performed, the gripper of the gripper device 9 opens, so that the paper sheet 2
Is held in the region of its trailing edge 11 and is held and braked by the suction device 8 due to the slower movement of the braking belt 5 so that the paper pile 12 is not damaged. It can be transported at a reduced speed. Above the sheet pile 12, a device for generating blown air may be provided to facilitate dropping of the sheet. The direction of the blown air is indicated by arrow 13.

As can be seen in FIG. 1, the braking belt 5 has a braking strap 3 rather than only one suction device 8.
For example, two or more suction devices 8 may be provided so that an appropriate number of sheets 2 can be braked during one round of travel. The suction device 8 works in combination with the suction box 7 so that the negative pressure in the suction box 7 acts on the sheet 2 when traveling on the suction box 7.

In particular, the suction device 8 is embodied as a suction rod which extends in a direction perpendicular to the direction of circulation of the braking strap 3, the suction rod being provided on its upper side with the appropriate paper. It may also have a row of openings which work in combination with the trailing edge 11 of the leaf 2.

FIG. 2 shows that the gripper device 9 has moved further by being operated, that is, the above-described paper sheet 2
1 is still grasped by the suction device 8 at its trailing edge 11, while the trailing paper sheet 2 is already territorially above the device 1 but has not yet been sucked there. The device is shown. The suction is performed only when the trailing edge 11 of the succeeding sheet 2 faces the suction device 8. This ensures braking of the paper sheet 2 without ink stains.

FIG. 3 shows the device according to FIG. 1 in the operating state in which the subsequent sheet 2 described above has already been conveyed regionally onto the sheet pile 12.

FIG. 4 shows a plurality of braking straps 3 which are spaced apart from one another in the direction perpendicular to the sheet movement direction 14.
1 shows a device 1 having As a result, a row of braking straps 3 is formed next to each other, which braking straps 3 have a mutually unsynchronized circulation speed so that the braking of the sheets as described above takes place. Move. FIG. 4 shows a part of the paper sheet 2 whose trailing edge 11 has already been released from the braking strap 3. Therefore, the speed of the sheet 2 is already braked so that it can be dropped onto the sheet pile 12. Floating guide regions 15 are formed on the outside of the braking strap 3 and between the individual braking straps 3. The floating guide areas 15 are formed in the moving direction 14 of the paper sheet 2.
It is supplemented by another floating guide area 16 which is located in front of the braking strap 3 in FIG. When viewed in the direction opposite to the direction of movement 14 of the sheet 2, the floating guide area 16 is connected to an air outflow zone 17, to which a further floating guide area 18 is connected. The floating guide areas 16, 18 and the floating guide area 15 have a large number of air nozzles (not shown in detail) from which an air stream 19 emerges, which air stream 19 is A carrier air layer that collectively transports the paper sheets 2 in a floating manner is generated. The floating guide area 15 and the floating guide area 16 form a first area 20 in which the air flow 1
9 is oriented in a direction opposite to the movement direction 14 of the paper sheet 2. The tension of the sheet 2 achieved thereby is such that the precise and definitive grasping of the trailing edge of the sheet 2 by the suction device 8 thereby facilitates the movement of the trailing edge 11 of the sheet. Is advantageous for the way. The floating guide area 18 forms a second area 21 in which the air flow 19 is in the same direction as the movement direction 14 of the paper sheet 2. Therefore, the first and second regions 20, 21
Of the impinging air streams 19 together in an air outflow zone 17 formed as a gap 22 extending over the entire width of the guide track for the sheet 2.

Due to the carried air layer formed by the air stream 19, the paper sheet 2 whose front edge is grasped by the gripper of the gripper device 9 can be brought into contact with the brake strap 3 without contact by the gripper device 9. The trailing edge 11 is moved during its passage as grasped by the suction device 8 on the braking strap 3.

Due to the slower circulation speed of the braking strap 3 to which the suction device 8 holding the trailing edge 11 of the paper sheet 2 is attached, the speed of the paper sheet 2 is not damaged on the paper sheet 12. It is braked so that a drop without ink stains is performed. The non-uniform circulation speed of the braking strap 3, which is required for this, is generated by a drive, which is preferably designed as a servomotor M.

FIG. 5 shows, as an example, a part of the time course of the speed v at m / s of the suction device 8 of the braking strap 3. As can be seen there is initially a relatively low velocity v, which rises after time t ₁ ,
At the time t ₂ reached the highest value, it persists unchanged until the point in time t _3. After that, the speed v decreases again until reaching the time point t ₄ , and reaches the same value as at the time point t ₁ . Time interval t
_{At 2-} t ₃ , the paper sheet 2 is received. That is,
At this time interval, the suction device 8 for the braking strap 3
Has a high velocity v similar to the velocity v of the paper sheet 2. If subsequently the paper trailing edge 11 is held by the suction device 8, the braking movement occurs (time interval t ₃ -t _4), whereby the paper 2 is braked to a speed which is present at time t ₄ . After the time t ₄ , the release of the sheet 2 and thus the dropping onto the sheet pile 12 takes place. Subsequently, as at time t ₁ , the acceleration again occurs, so that the next sheet 2 is first sucked during the high speed and then braked.

FIG. 6 shows the braking belt 5 indicated by the solid line 24.
In addition to the time course of the velocity of the sheet, a diagram is shown in which the time course of the velocity of two sheets of paper 2, which are shown one behind the other in the area of the device 1 according to the invention, indicated by a chain line 23, is entered. There is. In effect, line 23 coincides with line 24 at their respective upper levels, their descending portions, and their respective lower levels. However, for clarity, we chose to display it out of agreement.
Particularly, at the moment of receiving the paper sheet by the suction device 8 or one of the plurality of suction devices 8, that is, when the trailing edge 11 of the paper sheet is sucked (time t ₅ in FIG. 6), the paper sheet 2
And the speed of the suction device 8 are the same. The speed of the suction device 8 becomes slower, and similarly, the speed of the paper sheet 2 becomes slower. The ends of the lines 23 which lie on the lower level (time points t ₆ , t ₆ ′) are respectively meant to be synchronous with the release of each leaf 2 carried out by the device 1.
As a result of this release, the leaf 2 now leaves the device 1 at a slower speed and falls on the pile 12 as its movement continues. The starting point of the line 23 on the right side in FIG. 6 (time t ₇ ) is that the next sheet following the delayed sheet 2 enters the area of the device 1, that is to say the suction at the time t ₅ ′. Meaning the same as entering the area of the device 1 to be re-released from the suction device at time t ₆ ′, as determined by the device 8 or one suction device 8 of the plurality. Where t ₅ and t
The time interval between ₅ ′, or between t ₆ and t ₆ ′, corresponds to the time cycle in which successive sheets 2 are conveyed by the respective gripper device 9 into the area of the device 1. It is equivalent.

As shown by the velocity diagram in FIG. 6, when the speeds of the sheet 2 and the suction device 8 are the same, the sheet 2 is periodically grasped by the suction device 8 and both of them are continuously detected. In order to realize the operation mode of simultaneous deceleration and, finally, release of the decelerated paper sheet by the suction device 8, the phase position of the suction device 8 circulating with the braking belt 5 is first determined by the suction device. 8 is opposed to the paper sheet when the speed of the suction device 8 reaches the speed of the undamped paper sheet 2, and the suction device 8 releases the paper sheet 2 (time t
_{After 6} or t ₆ ′), it is chosen such that it will be separated again from the conveying surface through which the succeeding and succeeding sheets 2 pass. This means that some suction devices 8 are naturally arranged along the braking belt 5 even if the suction devices 8 are arranged at only one position along the braking belt 5. The same is true for cases.

FIG. 7 shows a test print which can be realized by this device 1 for the first sheet 2 on the assumption that the device 1 according to the present invention is used as a sheet discharge device of a sheet-fed printing press. The operation mode of taking out paper sheets is followed by the second
The above-described operation mode, which is abbreviated as a braking cycle here, for the paper sheet 2 of FIG. 1, that is, the operation mode for dropping the paper sheet 2 onto the paper pile 12 at a slowed speed. In each case, on the one hand the sheet 2 (line 23 ') and on the other hand the braking belt (line 2').
4 ') in the form of velocity. As already described in connection with FIG. 6, the line 23 'and the line 24' are also used here.
Differs from the way shown in the figure, and is in the same region, that is, in the same region as in the operation mode of FIG. In the operating mode of unloading a trial print sheet, the braking belt 5 is activated by the gripper device 9 of the device 1 during the entire time cycle (corresponding to the time interval between t ₆ and t ₆ ′). The suction device 8 is controlled so as not to face the paper sheet 2 conveyed above. Furthermore, in this operating mode, the gripper device 9 is reached as soon as it comes to the time t ₅ which is entered in FIG. 7 and corresponds to that in FIG.
Does not request to release the paper sheet 2. The sheets 2 are further transported individually, in particular over the sheet pile 12, and fed to the inspection location.

The values given in FIG. 5 in combination with FIG. 7 reveal the particular advantages of the device 1 according to the invention with an electric servomotor. The advantages are, on the one hand, the function of damping the sheet 2 during the rapid succession of the sheet 2, which corresponds to the time cycle of modern sheet-fed presses,
On the other hand, it is only necessary to have suitable electrical control means in order to stop the above braking during only one selected machine time cycle.

In order to realize the movement course of the braking belt 5 as described with reference to the drawings, this braking belt 5 is operatively connected to the servomotor M in a shape-dependent manner. For this purpose, in the exemplary embodiment shown here, the drive device, the guide roller 4 and the braking belt 5, which are shown diagrammatically in FIG. 1, are formed by toothed belt devices. That is,
The rotation shaft of the servomotor M and the guide roller 4 on the left side of FIG.
Each have a pinion, a toothed belt is wound between these two pinions, both guide rollers 4 have gears on their outer circumferences, and a braking belt 5 has teeth that mesh with the gears of each guide roller 4 inside. are doing.

It is desirable that the servo motor be controlled so that the paper drop speed does not change even if the speed changes during the printing process.

With the device according to the invention, sheets are received, braked and dropped at defined points. There, the gripper opening is combined with the control of the braking belt. The targeted drop-in by means of the controlled braking projections contributes to a process-stable, defined pile formation and thus an edge-aligned paper pile.

[0033]

As described above, according to the present invention,
It is possible to brake the printed paper without ink stains.

[Brief description of drawings]

FIG. 1 is a schematic side view of a sheet braking device in a first operating state.

FIG. 2 is a diagram of the device of FIG. 1 in a different operating state without the drive device.

FIG. 3 is a view of the device of FIG. 1 without the drive device in yet another operating state.

FIG. 4 is a top view of the device of FIG.

FIG. 5 is a diagram showing a part of a time course of a speed of a braking belt as one example.

FIG. 6 between two successive cycles, two cycles in which two successive sheets are received and braked by a suction device, on the one hand FIG. 5 is a diagram showing the time course of the speed of a leaf (chain line) and, on the other hand, a braking belt (solid line).

FIG. 7 shows the speed of two successive sheets (chain line) on the one hand, and the braking belt (solid line) on the other hand, in different types of successive operation of the device according to the invention. It is a diagram of a time course.

[Explanation of symbols]

 1 paper leaf braking device 2 paper leaf 3 braking strap 4 guide roller 5 braking belt 6 arrow 7 suction box 8 suction device 9 gripper device 10 arrow (indicating gripper movement) 11 leaf trailing edge 12 paper pile 13 arrow ( Blow-out air) 14 Arrows (paper sheet movement direction) 15, 16 Floating guide area 17 Air outflow zone 18 Floating guide area 19 Arrow (air flow) 20 First area 21 Second area 22 Gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Richard Burghardt Mack Germany 68782 Bruhl, Sophie Scholstraße 14 (72) Inventor Roland Hilt Germany 67354 Remerberg, Kirchenweg 10 (72) Inventor Gerhard Polich Germany 69123 Heidelberg, Adlerstraße 5 Ar (72) Inventor Joseph Were 68723 Schwetzingen, Erfurtelstraße 13

Claims (17)

[Claims] 1. At least one braking strap with attached suction device, said braking strap comprising:
In a sheet braking device, in particular a device for a sheet ejecting device of a sheet-fed printing press, which is connected to a drive which produces a non-uniform circulation speed, said braking strap (3) circulates with it,
Having at least one discrete suction device (8) acting on a selectable partial area of the paper sheet (2) to be braked, in particular on the trailing edge (11) of the paper sheet, the rest of the paper sheet (2). The sheet braking device, characterized in that at least the part of the braking strap (3) facing the region of (3) does not have an active suction device (8). 2. A device according to claim 1, wherein the suction device (8) has at least one suction opening partially formed on the braking strap (3). 3. The suction device (8) comprises at least one suction element, in particular a suction cam or a suction rod, projecting outward from the contour of the circular movement of the braking strap (3). The apparatus according to 1 or 2. 4. From the first aspect, when the trailing edge (11) of the paper sheet is sucked, the driving device transmits a speed corresponding to the speed (23) of the paper sheet to the braking strap (3). The apparatus according to any one of paragraphs 3. 5. Device according to claim 1, wherein the drive reduces the circulation speed of the braking strap (3) after suction of the trailing edge (11) of the sheet. 6. Device according to claim 1, wherein the drive device is an electric servomotor (M). 7. The braking strap (3) according to any one of claims 1 to 6, wherein a floating guide device (15, 16, 18) for the paper sheet (2) is attached. apparatus. 8. The floating guide device (15, 16, 18)
8. A plurality of floating guide areas (16, 18) of said are connected to said braking strap (3) on the front side as viewed in the paper movement direction (14). The device according to. 9. The floating guide device according to claim 1, wherein at least one floating guide region (15) of the floating guide device is arranged laterally of the braking track device (3). apparatus. 10. A plurality of braking track devices (3) are laterally spaced from one another.
The apparatus according to any one of 1. 11. Device according to claim 1, wherein there is one floating guide area (15) between any two of the braking track devices (3). 12. The floating guide device (15, 16, 18) attached to the braking track device (3) has a large number of air nozzles, from which air flow (1).
Device according to any one of claims 1 to 11, wherein 9) exits, which produces a supported air layer. 13. The air flow (19) is directed in the first area (20) in a direction opposite to the sheet movement direction (14). The described device. 14. The device according to claim 1, wherein the air flow (19) is directed in the direction of the sheet movement (14) in the second region (21). 15. The device according to claim 1, wherein an air outflow zone (17) is formed between the two areas (20, 21). 16. The method according to claim 1, wherein the first area (20) is ahead of the second area (21) in the sheet movement direction (14). The device according to. 17. A braking belt (5) forming the braking strap (3) is connected to the servomotor (M),
A device according to any one of claims 1 to 16, which is operatively coupled in a shape-dependent manner.