EP1208975B1 - Method and device for determining the overlap of a signature - Google Patents

Abstract

The folding system has a folding mechanism (10) with adjustable overlap for folding signatures (18), an optical sensor (28) for measuring the presence of folded signatures and a controller (30) connected to the folding mechanism and optical sensor for determining the overlap of the folded signatures. The folding mechanism is a drum folding mechanism with a pair of folding rollers. Independent claims are also included for the following: a method of folding signatures.

Description

The invention relates generally to printing machines, and more particularly to an apparatus and method for adjusting an overlap on a folded signature, according to the preambles of claims 1 and 9.

Such an apparatus and method are known from US-6,024,682. Web-fed rotary printing machines print on an endless material web, for example paper. In a folder of the printing machine, the endless web is then cut and folded in a cutting unit in signatures.

One way to fold the resulting signatures is to use a so-called wheel folder or drum folder which has a cylinder with rotating (folding) knives which alternately pass over the peripheral surface of the cylinder to fold the signature. The signature is held by puncturing needles at its leading edge and usually folded near the center of the signature by a folding knife. The fold is forced by the folding blade between two rotating folding rollers, which are arranged adjacent to the cylinder and take the signature along the fold at a gap, set the fold and lay out the folded product or further, for example to a paddle wheel unit. Wheels or drum folders are described, for example, in Chapter 6, (pages 136-154) of the book "Newspaper Presses" by William Braasch.

If the signature is folded in half exactly, there is no overlap that represents the distance between the leading edge and the leading edge of the signature. Accordingly, an overlap occurs when the signature is folded off-center because the leading and trailing edges are spaced apart.

In a drum folder, the overlap changes as the speed of the machine changes. Accordingly, in a slow test run before the actual production, the overlap differs from the overlap that occurs at the full production speed. Accurate measurement and adjustment of the overlap during the course of the folder is therefore important in a drum folder.

The overlap of the signature can be done by moving the folding blades relative to the puncturing needles in the circumferential direction. The distance between the puncturing needle as well as the leading edge of the signature and the location where the circumferential folding blade forces the signature into the folding unit determines the overlap.

The "Patent Abstracts of Japan" no. 62-70174 describe a helical gear mechanism for adjusting the amount of overlap of folded sheets without stopping the machine. Separately formed needle segments and folded edge segments are arranged alternately on a folding drum. The needle-side associated helical gears are axially displaced by a rotating drive mechanism.

The device of "Patent Abstracts of Japan" no. 62-70174 has no controller that controls the mechanism for setting the overlap, and the apparatus does not seem to be able to independently correct the overlap. Furthermore, there appears to be no optical sensor and no feedback mechanism for detecting the overlap.

The "Patent Abstracts of Japan" no. 6-255881 describe an overlap setting apparatus in which data associated with each speed of the printing machine is fed to a longitudinal side as a control signal to an actuator motor of a control unit. A deviation of a rotation speed detection signal of the motor from the above-mentioned control signal is supplied as a control signal to the motor and the rotation speed controlled until an overlap which is within an allowable range is obtained.

The device of "Patent Abstracts of Japan" no. 6-255881 has the disadvantage that no sensor is provided which automatically detects the overlap of a folded signature. Thus, although the apparatus would quite well be capable of altering the overlap of a folded signature in response to control signals, it does not appear Having feedback mechanism capable of detecting the actual overlap of a folded signature.

It is an object of the present invention to provide an apparatus and method for measuring and controlling the overlap of folded signatures. It is another or another object of the present invention to provide an optical sensor and a controller for measuring and adjusting an overlap of folded signatures. An additional object of the present invention is to provide an automatic feedback mechanism for automatically adjusting the overlap of folded signatures.

In accordance with the present invention, a folding system includes a foldable overlay folder for folding signatures to form folded signatures, an optical sensor for measuring overlap on the folded signatures, and a controller connected to the folder and optical sensor for adjusting the signature Overlap on.

The adjustable overlap folder is preferably a wheel folder or a drum folder having folding rollers for receiving the signatures such that folded signatures are formed.

The drum folder may further comprise an outer puncture tray that is circumferentially movable relative to the folding blades of the drum folder. The outer puncture shell offers the advantage of automatically adjusting the position of the signature with respect to the folding blades, so that the position of the fold can be changed.

The optical sensor may detect the first edge (the folded edge) of the folded signature to send a signal to the control unit as the seaming edge passes the optical sensor. When the folded edge of the folded signature passes the sensor, the optical sensor is triggered. The sensor may be triggered by an interruption in an electromagnetic beam emanating from the optical sensor. If the beam hits the sensor again, ie after the interruption of the sensor the trailing edge (either the trailing edge of the signature or the trailing edge of the signature) is detected. Accordingly, the time t required for the entire signature to pass the optical sensor is known. The triggering of the optical sensor provides the advantage of an automatic and efficient accumulation of data that can be used to calculate the overlap of the folded signature.

The controller preferably includes a processor for receiving the speed of the folded signature and the signals transmitted by the optical sensor to determine the length of the folded signature s. When the optical sensor is triggered, the optical sensor sends a signal to the controller. Accordingly, the time t required for the folded signature to pass can be calculated. For example, the controller may start an internal timer after receiving the first signal, and stop that counter after receiving the second signal. The elapsed time t is multiplied by the speed v of the signature, which is a predetermined constant, to obtain the length s of the signature according to the relationship s = t * v. The speed can be determined by the speed of the folding rollers.

The processor preferably uses the length s of the folded signature and a portion length of the signature c to calculate the overlap of the folded signature D. In order to calculate the overlap of the folded signature D, the length of the signature s is multiplied by 2 and from this value the section length c is subtracted, according to D = (s * 2) -c. The section length c is the length of the entire paper and is determined from the size of the signatures separated by a cutting cylinder from a web. The calculation provides the advantage of automatically determining the correct overlap on the folded signature without requiring an operator to measure the overlap.

The processor preferably calculates whether the overlap is positive or negative, ie, for example, the sign of the overlap, based on an overlap of subsequent folded signatures and the previously calculated overlap. The bill offers the advantage that the sign of the overlap can be determined without the printing press must be stopped for this, or an operator must be present. Furthermore, the obtained data can be used to automatically set the device to an operator-specific overlap distance.

The determination of the sign of the overlap can be effected by comparing the overlap of a primary folded signature with the overlap of a subsequently folded signature. The absolute value of the primary overlap is determined, and the controller then sends out a control signal to circumferentially move the outer puncture cup a small distance relative to the blade carrying the folding blade, for example, by increasing the distance between the puncturing needle and the needle Folding knife for a signature. The outer puncture cup therefore rotates circumferentially with respect to the puncture tray with the folding blades by a small amount, preferably such that the difference between the primary overlap and a subsequent overlap equals the minimum distance that the optical sensor can perceive; but in any case smaller than the primary overlap. If the overlap of the primary signature is positive, increasing the distance between the dot reing and the folding blade results in a decrease in the overlap of the subsequent signature. If the overlap of the primary signature is negative, increasing the distance increases the absolute value of the overlap of the signature. The sign of the overlap of the primary signature can thus be determined. It should be noted that the overlap on the primary signature may also be zero, in which case a determination of the sign is not required.

For example, if the outer puncture shell is rotated circumferentially with respect to the folding blade shell, eg, clockwise to increase the distance between a puncturing needle and the folding blade, the controller may compare the subsequent overlap D ² with the primary overlap D ¹ to indicate the sign of the primary To determine the signature. If the difference between the primary overlap D ¹ and the succeeding overlap D ² gives a positive number, ie, D ¹ - D ² > 0, the primary signature has a positive sign for the overlap. Conversely, the primary signature has a negative sign for the Overlap when the difference between the primary overlap D ¹ and the succeeding overlap D ^{2 is} a negative number, ie D ¹ - D ² <0.

The outer puncture shell can likewise be easily rotated in the circumferential direction relative to the folding blade shell in order to reduce the distance between the puncturing needle and the folding blade, z. B. counterclockwise. The controller may then compare the subsequent overlap D ² with the primary overlap D ¹ to determine the slope of the primary signature. If the difference between the primary overlap D ¹ and the succeeding overlap D ^{2 is} a negative number, ie, D ¹ - D ² <0, the primary signature has a positive sign for the overlap. Conversely, the primary signature has a negative sign for the overlap if the difference between the primary overlap D ¹ and the succeeding overlap D ^{2 is} a positive number, ie, D ¹ - D ² > 0.

The controller preferably has the capability of automatic feedback to use the data for the overlap and the data for the positive or negative slope to automatically configure the overlap on the folded signature in accordance with a user-specific overlap. The adjustment of the overlap is hereby achieved in that the outer puncture shell is moved relative to the folding blades in response to the control signal emitted by the control device. To determine the correct control signal, the controller determines the sign of the folded signature (if not previously known) and then compares the overlap on the folded signature with a desired overlap previously entered by the operator. The comparison provides the advantage that the overlap on the folded signatures can be automatically adjusted in accordance with operator-specific overlap without stopping the folder. In this case, the feedback control can be performed by comparing the primary overlap D ¹ with a desired overlap x ₁ input by the operator. The desired overlap x ₁ may be a positive value, a negative value, or zero.

The controller then makes a determination as to whether or not the primary signature has a positive or negative sign, and moves the outer puncture cup by the desired amount by rotating the puncture cup with respect to the folding blade cup in the circumferential direction.

If the primary signature has a positive overlap indication and the primary overlap D ^{1 is} greater than the desired overlap X ₁ , the controller sends out a control signal that causes the outer puncture cup to move circumferentially such that the distance enlarged between the puncture needle and the folding blade. However, if the primary overlap D ¹ is less than the desired overlap X ₁ , the controller sends out a control signal that causes the outer puncture cup to rotate circumferentially to decrease the distance between the puncturing needle and the folding blade.

The folding cylinder preferably includes at least one puncturing needle attached to an outer puncture tray to hold the leading edge of the signature.

The drum folder may also preferably further include a cutting cylinder and an anvil or grooved bar attached to the outer puncture tray to assist in cutting the web.

The present invention provides a method for folding signatures, which comprises cutting a web with an adjustable overlapping folder to form signatures, folding the signatures with the aid of the folded signature forming folder, optically measuring the overlap in the sheet folded signatures and adjusting the overlap as a function of the measurement.

The step of folding may further include puncturing, ie, pinning the signature by means of puncturing needles at the leading edge of the signature, and contacting the signature at a set distance from the leading edge of the signature include a folding blade. By puncturing the leading edge and contacting the signature at a set or predetermined distance from the leading edge, the signature is stabilized and the length of the overlap can be determined.

The method for folding signatures further comprises measuring a speed of the folded signatures. The speed measurement allows the determination of the length or size of the overlap when the speed of the drum folder or wheel folder is changed.

The method for folding signatures may further include changing the set distance to change the overlap. The advantage offered by the fact that the set distance is changed is to see that the set length of the overlap of a signature can be changed.

The step of changing the distance or the set length further preferably comprises changing the set distance by using a feedback from a controller. The use of a feedback from a control device has the advantage that an automatic calibration of the length of the overlap is provided.

The invention will be described below with reference to a preferred embodiment with reference to the drawings.

Fig. 1

Eine Seitenansicht eines Trommelfalzsystems;

Fig. 2

Eine Seitenansicht einer gefalzten Signatur;

Fig. 3

Eine Seitenansicht von verschiedenen gefalzten Signaturen.

In the drawings show:

Fig. 1

A side view of a drum fold system;

Fig. 2

A side view of a folded signature;

Fig. 3

A side view of different folded signatures.

Fig. 1 shows a side view of a preferred embodiment of the invention using a drum folder system 1 having an adjustable lap folder 10. The web 16 enters the folder 10 which has a cutting cylinder 12 and an outer puncture tray 14 which is driven and is circumferentially movable with respect to a rotating folding blade tray 15. The cutting cylinder 12 includes a cutting unit 11, such as a knife, which cooperates with an anvil or grooved bar 20 attached to the outer puncture tray 14 to cut the web into at least one signature 18. A puncturing needle 22 or pin 22 secured to the outer puncture tray 14 holds a leading edge of the signature 18 and aligns the signature 18 with a folding blade 24 of a plurality of folding blades disposed on the folding blade tray 15. When the signature 18 rotates a certain distance with the cylinder 14 and 15 having the shell, the folding blade 24 provides a fold and pushes the signature 18 in the access of a plurality of folding rollers 26, which cooperate with each other to set the fold and to promote the folded signature 18 to a plurality of conveyor belts 32. On their way to the conveyor belts 32, the folded signatures 18 pass through an optical sensor 28, e.g. may include a light source and a light receiver. The optical sensor 28 detects when an edge of the folded signature 18 passes, e.g. in that the passage of the signature 18 interrupts an electromagnetic beam emitted by the optical sensor 28 and sends a signal to a controller 30. The controller 30 uses the signal from the optical sensor 28 to perform calculations as described with reference to Figs Fig. 2 will be described below. If the data sent to the control unit 30 does not match the data specified by an operator, the controller 30 sends out a control signal to modify the position of the folding blade 24 with respect to the signature 18, which may be provided by, for example, providing feedback , as described with reference to FIG. 3. Fig. 1 also shows a folded signature with a negative overlap D.

2 shows a side view of a folded signature 18. When the optical sensor 28 detects passing of the folded edge 50, an electromagnetic beam emitted by the optical sensor 28 is interrupted and the optical sensor 28 transmits a signal to the controller 30. The controller 30 starts an internal counter mechanism after having received a first signal and stops the internal counter mechanism after having received a second signal, namely when the beam is received again or is no longer interrupted, z. B., when a trailing edge 52 of the signature passes the sensor 28. Then, the controller 30 calculates the time t that the folded signature 18 took to pass the optical sensor. The controller 30 then multiplies the time t by the velocity v of the folded signature 18 to calculate the length (s) 58 of the folded signature 18; according to s = t * v. The speed v may be determined by the rotational speed of the folding rollers 26, and may be entered by the operator into the controller 30, or may be determined in another desired manner. The controller 30 calculates an overlap (D) 60 by multiplying the length (s) 58 of the folded signature 18 by the number 2 and then subtracting the section length (c) 56; according to D = (s * 2) - c. The section length (c) 56 is the entire length of the signature 18 and is determined by the speed of the cutting cylinder 11 or otherwise, for example by operator input.

Fig. 3 is a side view of signatures to better explain the process of determining the sign of the overlap according to the present invention. A controller 30 (FIG. 1) may receive data regarding a positive primary overlap 70 on a primary signature 72 having a positive overlap.

Since the primary overlap 70 is not equal to zero, the controller 30 sends out a control signal 30 to move the outer puncture tray 14 circumferentially about the folding blade tray 15 such that the difference between the primary overlap 70 and a subsequent overlap 76 essentially corresponds to at least a minimum distance that the sensor can barely pick up or perceive, and which is smaller than the primary overlap 70th

For example, the movement intentionally reduces the distance between the puncturing needle 22 and the folding blade 24. The controller 30 may subsequently Compare the previous overlap 76 D ² with the primary overlap 70 D ¹ to determine the sign of the overlap of the primary signature 72. Since the difference between the primary overlap 70 D ¹ and the subsequent overlap 76 D ^{2 is} a negative number, since 76 is greater than 70, the primary signature 72 has a positive sign. Conversely, the subsequent overlap 76 D ^{2 would be} less than the primary overlap 70 if the primary overlap 70 D ^{1 were} negative. If there is no difference between the primary overlap 70 D ¹ and the subsequent overlap 70 D ² , an error has occurred and the controller 30 sends an error signal to warn the operator.

Also shown in Fig. 3 is a signature 78 with a positive sign for the overlap, a signature 85 where the sign of the overlap is zero, and a signature 80 with a negative sign for the overlap.

An operator can adjust the overlap between these positions by changing the distance between the puncturing needle 22 and the folding blade 24 by moving the puncture cup 14 circumferentially of the folding blade tray 15. As the puncture tray 14 is moved faster than the folding blade tray 15, the distance between the puncturing needle 22 and the signature folding blade 24 increases and the overlap becomes increasingly negative such that a positive overlap becomes smaller and a negative overlap becomes larger in absolute terms. An overlap of zero would therefore become negative, i. from a signature similar to the signature 85 to a signature similar to the signature 80. As the puncture tray 14 is moved slower than the folding blade tray 15, the overlap becomes increasingly positive.

The operator can thus set a desired positive or negative overlap on the controller 30 and the feedback moves the puncture tray according to the folding blade tray until the desired overlap is achieved, at which the controller ensures that the folding blade tray 15 and the puncture tray 14 with the to rotate at the same speed.

As used herein, the term "optical sensor" may include any type of radiation-based sensor using, for example, radio waves, infrared, ultraviolet or visible light beams.

List of reference numbers

1

Rotary blade system

10

Folder with adjustable overlap

11

cutting unit

12

cutting cylinder

14

outer puncture shell

18

signature

20

Anvil / grooved strip

22

Puncturing needle

24

folding blade

26

folding rollers

28

optical sensor

30

control device

32

conveyor belts

50

folding edge

52

rear edge

56, c

section length

58, s

Length of a folded signature

60, D

overlap

70

primary overlap

72

primary signature with positive overlap

76

subsequent overlap

78

Signature with positive sign for the overlap

80

Signature with negative sign for the overlap

85

Signature with zero as sign for the overlap

t

Time

v

speed

Claims (10)

1. A folding system having
   a drum folder (10) with an adjustable overlap (60) for folding signatures (18),
   a sensor (28) for detecting the presence of folded signatures (18) and a control device (30) which is connected to the folder (10) and the sensor (20) and determines an overlap (60) of the folded signatures (18),
   the control device (30) controlling or regulating the overlap (60) of the folder (10),
   characterised in that
   the sensor is an optical sensor (28),
   in that the folder (10) contains a perforating needle (22) which is rotatable in the circumferential direction with respect to a folding blade (24),
   and in that the control device (30) controls or regulates the overlap (60) of the folder (10) through the perforating needle (22) being rotated in the circumferential direction with respect to the folding blade (24).
2. A folding system according to Claim 1,
   characterised in that
   the folder (10) contains a folding-roller pair (26).
3. A folding system according to Claim 1,
   characterised in that
   the control device (30) contains a processor for detecting a folded edge (50) on the folded signatures (18).
4. A folding system according to Claim 1,
   characterised in that
   the control device (30) contains a processor for detecting a following edge (52) of the folded signatures (18).
5. A folding system according to Claim 1,
   characterised in that the control device (30) contains a processor for calculating the length (58) of a folded signature (18).
6. A folding system according to Claim 1,
   characterised in that
   the control device (30) contains a processor for calculating a sign for the overlap (60).
7. A folding system according to one of Claims 1 to 6,
   characterised in that
   the control device (30) supplies feedback to the folder (10).
8. A folding system according to Claim 1,
   characterised in that
   the folder (10) contains a cutting device (11) and an anvil (20) which is fixed to the outer shell and promotes the cutting of the web by cooperating with the cutting device (11).
9. A process for folding signatures,
   having the following process steps:

   folding the signatures (18) in a folder (10); and measuring the folded signatures (18) with a sensor (28) to determine an overlap (60),

   characterised in that
   the step of folding comprises perforating the leading edge of a signature (18) and contacting the signature (18) with a folding blade (24) at a set spacing from the leading edge,
   in that this further comprises altering the set spacing to alter the overlap (60),
   in that the set spacing is altered by using feedback from a control device (30),
   and in that the sensor is an optical sensor (28).
10. A process according to Claim 9,
    characterised in that
    this further comprises measuring the speed (v) of the folded signatures (18).

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