DE102007061396A1 - Overshooting-sheet e.g. paper, shaking preventing device for sheet-fed printing press, has follower roller formed as overshooting brake such that stopping unit stops roller during change of detected speed, where sheet is fixable by roller - Google Patents

Abstract

The device has a follower roller for scanning a scaled transported sheet stream, and detecting conveyance speed of the sheet stream. The follower roller is formed as an overshooting brake (4) such that a stopping unit is attached to the roller and stops the roller during change of the detected speed, where a sheet causing the speed change is fixable by the stopped roller. The roller is arranged outside of the sheet stream, which is conveyed by belts such as suction belts (5), of a feed table (1).

Description

The The invention relates to a device for preventing the entry of overspill in a sheet-fed printing machine according to the preamble of 1st claim.

On Schuppenanlegern of sheet-fed presses are individually from a pile of conveyed sheet deposited in dandruff formation, wherein the bow end of the respective preceding arc over the beginning of the bow of the subsequent bow is. The scaly formation is continuously promoted towards a landing line, the front bow being at front stops (Front marks) aligned and then by moving sideways is brought to side marks in a defined retraction position, then individually accelerated to machine speed and to be fed into the first printing unit.

Especially in the case of adhesive or electrostatically sensitive substrates, such as As plastic films or coated papers, it comes it always causes problems when separating the bow due the adhesion superimposed sheet, so that two or more sheets are left over each other and not completely dandruffed (education of double or multiple sheets) or for entrainment of the subsequent, only in the front marks incoming bow with the sheet already peeling off, entering the first printing unit (early or overshoot arch) or for skewing the sheet when singling (oblique bow). In these cases can by simultaneously feeding multiple sheets in the pressure zone caused pressure disturbances and printing machine damage or in the case of oblique sheets, waste paper is produced.

to Detection of double or multiple sheets is known, double sheet control devices (DBK) in the area of the shingled stream or the laying line, which interrupt the sheet feed to the printing press, as soon as a double or Multiple arc is detected. To prevent the entry of Oblique or overshoot arch in the printing press However, the known configurations are not suitable.

From the DE-OS 24 18 881 is a bow lock known for sheet processing machines. In this case, it is proposed that a photoelectric sensing element scanning the sheet position associate an actuating mechanism with retaining members which hold the misplaced sheets on the contact table. As the actuating mechanism, a cylinder-piston unit is used and the holding members can be formed from holding shoes, holding fingers or disc segments.

adversely At this solution is that uses a sensor device which is responsible for error-free detection of the misfed arc energy consumed. It also becomes an additional switching element needed to trigger the controls only after releasing the misapplied bow by the above to ensure lying bow. The of the holding organs fixed sheets can only work against the direction of sheet travel taken from the investor.

From the DE 100 33 638 A1 For example, a sheet feed monitoring apparatus for a sheet processing machine and a method for controlling sheet flow construction of the sheet stream are known. The monitoring device comprises at least one scanning element arranged above or below a sheet flow, which is movable by means of an actuator in the direction of the arc current. The actuator contains at least one piezoelectric actuator or is formed by a piezoelectric actuator.

adversely At this solution is that the monitoring device having a separate actuator with a piezoelectric actuator, the requires a power supply that provide high voltages got to. It also requires a defined counterpressure element, by a distance measurement between the probe element and the counter-pressure element to carry out exactly.

From the DE 103 45 488 B3 For example, a method and an apparatus for detecting overspill is known. In this case, an acceleration sensor is arranged above the feed table for detecting the sheet movement. If a sheet conveyed to the front marks is entrained by the withdrawing sheet, which is already being accelerated by the pre-grippers, its forward acceleration exceeds the normal sheet acceleration for the measuring location or its speed increases compared to the constant conveying speed of the scale flow. This deviating acceleration is detected by the acceleration sensor. An output signal to the machine control is activated, whereupon a warning signal is issued by the machine control and measures for the retention of the over-shoot and the blocking of the investor are triggered.

adversely At this solution is that an acceleration sensor is provided is that converts the detected acceleration into an output signal, which was first converted by other adjusting mechanisms into an adjusting movement must become. There are also cable connections and external adjusting mechanisms necessary.

The The object of the invention is a device for preventing the entry of overshoot sheets into a sheet-fed press, which can be realized with little economic effort.

According to the invention the object by a device having the features of the first claim solved.

The Invention has the advantage that the device with simple means can be realized and no printing material-dependent settings requires. Furthermore, it is only the incorrectly guided bow held back while the front bow is properly in the printing machine runs in, so that the waste of waste is lower. In a preferred embodiment of Invention are no longer separate sensor and actuator devices required, eliminating disruptive cable connections. The simple construction of the device is a reliable Detection and secure fixation of overshoot arch guaranteed. There are no defined counter-pressure elements required, whereby an accurate adjustment, z. B. the distance of a Touch roller for counter-pressure element, not applicable. Continue to be Advantageously extensive sensor, cable, control and Control elements for the overflow control unnecessary.

in the The invention will be explained by way of example below. The accompanying drawings are schematic represents:

1 : Side view of a shed feeder with overshoot brake in proper bow position;

2 : Side view of a shed feeder with activated overshoot brake at the time of taking off a sheet that entrains an overshoot.

Like from the 1 an embodiment of the invention are located on a feed table 1 a Schuppenanlegers a sheet-fed rotary printing machine scaly superimposed bow 8th (Sheet of paper), the respective subsequent sheet lies with its leading edge under the previous sheet. The bows 8th who the continuously by funding, z. B. circulating suction belts 5 , at a speed that is about one-third of the printing speed, in the direction of laying line promoted. Along the landing line transverse to the conveying direction are dependent on the sheet size several leading brands 2 arranged, which act as stops for the sheet leading edge and clock-controlled from the transport plane of the sheet are swung away as soon as a sheet is drawn into the first printing unit. Between feed table 1 and first printing unit are at least pre-gripper 3 provided that the aligned sheet when peeling from the feed table 1 accelerate to print speed.

Above the feed table 1 At least one sensing roller is arranged in dependent on the sheet length L distance from the lay-up line. This sensing roller is associated with a lever arm mounted on a frame-mounted but displaceable guide element. On the lever arm, the sensing roller is rotatably mounted, wherein the sensing roller by gravity or by suitable pressing means, for. B. springs, is employed with a defined contact force on the surface of the arc current. Of course, other holding systems or pressing means for the follower roller can be used.

According to the invention, the follower roller is an overshoot brake 4 educated. In this case, the overshoot brake 4 be formed as extending over the width of the printing machine suction roll or consist of axially juxtaposed suction rings. In a further development of the embodiment of the overshoot brake 4 as a suction roll, the suction air can be switched on and / or regulated if necessary. In an alternative embodiment of the overshoot brake, a roller with a segmented or continuously closed and / or rough surface can also be used. The overshoot brake 4 can have a color-repellent surface and rotate exactly at the speed of the suction belts 5 , so that no difference speed between the top and bottom of the arc current occurs. The overrun brake is driven 4 from the arch lying in the scale formation 8th , The bows 8th can by means of the overshoot brake 4 additionally on the feed table 1 be guided in the shed formation. Alternatively, the overshoot brake 4 itself, z. B. by an electric motor, are driven with sheet conveying speed.

According to the invention as Überschussbremse 4 trained sensing roller means associated with those with jerky speed change and thus acceleration of the overshoot brake 4 another rotation of the overshoot brake 4 is prevented. Through the stilled, on the overflow bow 9 pressing overshoot brake 4 will be the overshoot bow 9 on the feed table 1 braked and fixed. The means for stopping the overshoot brake 4 can preferably be designed as a dynamic locking gear or as an inhibiting gear. This lock gear is within the overspeed brake 4 arranged and cooperates via the lever arm with the frame-fixed guide element, such that the rotation of the overrun brake 4 is prevented when blocking. The dynamic locking gear can according to a Roll belt be formed, the jerky speed increase, the rotation of the overrun brake 4 locks and thus prevents overshoot of a bow. Alternatively, it is also conceivable, the acceleration by means of a sensor, for. B. electronically, and to realize a rotation stop via a controllable by the sensor braking device of overshoot brake.

It is essential that the overshoot brake 4 at a distance from the landing line that is greater than the processed arc length L and less than the sum of the arc length L and the period length a. Where the relay length a is the distance of the bow in the squadron, that is the bow lying in the scaly formation 8th , is. Optimal is a distance that is only slightly larger than the respectively processed arc length L, so that the overshoot brake 4 after removing the foremost bow 7 can continuously record the underlying following arc over as long a distance as possible. This ensures that the overshoot brake 4 a possibly entrained overflow bow 9 despite the reaction times of the mechanical locking gear can still hold back safely. The peeling bow 7 is therefore not mitstoppt. The guide element, and thus the overshoot brake 4 , Is adapted to format adaptation in accordance with in and opposite to the sheet conveying direction displaced.

For the operation of the invention Facility:

In a shed feeder, the bow 8th during normal sheet travel, with the load carried by the feeder (eg suction belts) 5 ) given usually constant speed to the landing line promoted, each with a bow 6 in the front lays 2 enters, aligns and subtracts. Now one to the front brands 2 moving bow 6 from the subtending bow 7 that already from the pre-grippers 3 is accelerated, entrained, it is an overshoot 9 , like in the 2 shown. Once this overshoot 9 from the withdrawing bow 7 It is also accelerated. Immediately the acceleration of the overshoot arc 9 to the overshoot brake 4 transmitted and by the present invention blocking the Überießbremse 4 a fixation of the overshoot arch 9 on the feed table 1 triggered. The overshoot bow 9 So it will be even before reaching the front makes 2 from the overshoot brake 4 stopped. The overshoot brake 4 acts on the back arch area of the overshoot arch 9 and presses it over the width of the press on the feed table 1 in that this is fixed and can not get into the printing press. A corresponding signal to the machine control is generated, so that the machine control can issue a warning signal "overshoot arch present".

Simultaneously with the triggering of the overshoot brake 4 the investor is shut down immediately. In order to exclude damage within the press, an additional machine stop is initiated as additional security. After unlocking the overshoot brake 4 can then the disturbing overshoot 9 from the feed table 1 removed and continue printing.

For the overrunning brake function 4 is the manual or automated positioning above the feed table 1 depending on the sheet format requirement. For storage of the overrun brake 4 is a format length variable and frame-fixed arrangement of the overrun brake 4 intended. If necessary, the overrun brake can 4 also be assigned to another bow in the season.

1

feed table

2

front lays

3

pregrippers

4

Excessive brake

5

suction belts

6

In the front marks are filed bow

7

from Baking table subtending bow

8th

In the scale formation lying bow

9

Excessive bow

a

Season length

L

arc length

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2418881 A [0005]
• - DE 10033638 A1 [0007]
• - DE 10345488 B3 [0009]

Claims (11)

Device for preventing the entry of overshoot arch into a sheet-fed printing machine with a feeler roller for scanning a scuped conveyed sheet flow, wherein with the feeler roller the conveying speed of the sheet flow is detectable, characterized in that the feeler roller as Überießbremse ( 4 ) is formed, such that the sensing roller are associated with means by which the sensing roller is stopped at a detected change in speed, wherein the speed change causing bow can be fixed by the shut-off sensing roller. Device according to claim 1, characterized in that the means associated with the feeler roll are designed such that that the feeler roll at a jerky speed increase can be stopped. Device according to claim 2, characterized in that that the sensing roller is a mechanical inhibiting or blocking gear with which the rotation of the follower roller in a jerky Speed increase is stoppable. Device according to one of the preceding claims, characterized in that the sensing roller is formed as a suction roller is. Device according to one of the preceding claims, characterized in that the sensing roller has a lateral surface with a high coefficient of friction, in particular a rough surface, having. Device according to one of the preceding claims, characterized in that the feeler roller above the of bands, in particular suction belts ( 5 ), a feed table ( 1 ) supported arc current is arranged. Device according to one of the preceding claims, characterized in that the sensing rollers constantly with a defined force on the surface of the bow of the Bogenstromes is adjustable. Device according to one of the preceding claims, characterized in that the follower roller is associated with the sheet, which enters the incoming into the first printing unit, deducting from the feed table sheet ( 7 ) follows. Device according to claim 8, characterized in that that the feeler roll depends on the arc length (L) is positionable such that its measuring location is at a distance from the Liner line larger than the arc length (L) and less than the sum of arc length (L) and relay length (a) in the scale formation (L + a). Device according to one of the preceding claims, characterized in that the sensing roller rolls on the sheet of the sheet flow and thus at the conveying speed of the withdrawing sheet ( 7 ) following sheet ( 6 ) rotates. Device according to one of the preceding claims, characterized in that by the follower roller when fixing an overshoot arch ( 9 ) a signal for the machine control can be generated.