EP0408490B1 - Method and device for counting printed products - Google Patents

Description

The present invention relates to a method and a device according to the preambles of the independent claims.

In the printing plants, the printed products, in particular newspapers and magazines, coming from the rotary machine are fed to the further processing stations (for example, inserting devices of primary and main products, addressing and packaging stations, etc.) via suitable conveying means. In today's highly automated printing plants, where most of the devices and processes are controlled centrally, it is very important to know at any time and for a large number of strategic locations how many products have passed or failed to pass through these locations (online recording and real-time processing of emissions or rejects). In view of the high conveying speed (e.g. 80,000 products per hour), it is also extremely important to have figures that are as precise as possible, because even small relative errors lead in absolute numbers to considerable deviations of the actual from the target sizes and accordingly significant economic disadvantages (loss of material, over fluid time consumption of printing line and staff, etc.).

Of course, these needs were recognized earlier and there are therefore already various methods and devices by means of which printed products can be counted. One difficulty that is particularly likely to affect measurement accuracy is that the printed products are normally in a so-called shingled stream, i.e. partially overlapping each other, which makes it much more difficult to identify, differentiate and record the individual specimens.

Conventional mechanical counting devices generally have a projecting tongue, which experiences a certain deflection in each case through the upper edges of the printed products conveyed past and springs back into the rest position after passing the upper edge. The number of deflection movements of this tongue is recorded by a counter. The source of the error of such counting devices consists primarily in the fact that, in the case of printed products which are provided with a pre-fold in order to ensure a precisely defined insertion of further printed products, individual printed products are often counted twice, since the tongue is separated by both the main and the Pre-fold is deflected. On the other hand, there is a risk that two or more printed products, which follow each other more closely than intended due to some irregularity, cannot be distinguished by the counting device because the projecting part between the closely consecutive upper edges does not reach the rest position. The same can happen if for some reason a printed product protrudes higher out of the stream of shingles, whereby the movable part is deflected to such an extent that it is no longer captured by the subsequent printed product. Due to the high contact pressure required Small folds in the printed product between the moving part and the product flow and the resulting friction often lead to incorrect deflection. On the other hand, there is a risk with very thin products that the desired deflection is completely omitted or at least not sufficient. Although the error rate is often only in the alcohol range, as already indicated above, it is beyond the acceptable tolerance limit for high-speed processes.

In addition to such mechanical devices, optoelectronic counters are also known which, for example, use a laser beam to scan the product stream flowing past and are able to recognize the individual printed products on the basis of differences in contrast. In addition to the fact that the accuracy of such counters can be significantly affected by strong light-dark differences on the printed products (photos, etc.), the high costs, which often lead to the fact that not all strategically desirable places, are particularly important a counter can be installed.

All these known counting devices have in common that they are based on a method in which the printed products conveyed past are to be recorded at a point which has already been precisely determined and fixed in advance. However, these static counting methods do not do justice to the constantly changing circumstances of a dynamic process.

The invention as set out in the characterizing parts of the independent claims seeks to remedy this.

The advantages of the present invention can essentially be seen in the fact that the counter is not based on a passive or static principle, but rather to a certain extent on an active or dynamic principle. The concept is based on the idea that the counting element does not simply "react" as usual, but rather "acts", which means that the counting element adapts to the varying circumstances of the product flow on its own initiative and the accuracy is considerably increased. However, the simplicity of the system also enables cost-effective designs.

Fig. 1A, 1B, 1C

das Prinzip des erfindungsgemässen Zählverfahrens;

Fig. 2

eine schematische Darstellung des erfindungsgemässen Verfahrens;

Fig. 3A, 3B

zwei Varianten des erfindungsgemässen Verfahrens;

Fig. 4

eine einfache Vorrichtung zum Antrieb der erfindungsgemässen Vorichtung;

Fig. 5A, 5B

eine erste Vorrichtung zur Durchführung des Verfahrens;

Fig. 6A, 6B

eine zweite Vorrichtung zur Durchführung des Verfahrens; und

Fig. 7A, 7B

eine weitere Vorrichtung zur Durchführung des Verfahrens.

The method on which the invention is based and a selection of embodiments based thereon are explained in more detail below with reference to drawings. Show:

1A, 1B, 1C

the principle of the counting method according to the invention;

Fig. 2

a schematic representation of the inventive method;

3A, 3B

two variants of the method according to the invention;

Fig. 4

a simple device for driving the device according to the invention;

5A, 5B

a first device for performing the method;

6A, 6B

a second device for performing the method; and

7A, 7B

another device for performing the method.

FIGS. 1A, 1B, 1C illustrate the basic idea of the method according to the invention in a schematic manner. In the form of a shingled stream partially overlapping printed products D are transported at the conveying speed v 1 in the indicated conveying direction, the illustration of the conveying means being dispensed with for the sake of clarity. According to the invention, a contact element K, which is shown in FIG. 1A in its starting position, is moved at a speed v₂ which is higher than the conveying speed v₁, preferably parallel to the shingled stream, and with the trailing edge (trailing fold) F _{k of} the printed product D _k in Brought into contact. This contact is interpreted as a counting pulse by suitable means, which will be discussed in more detail in connection with the following figures, and registered by means of a counter (not shown) (FIG. 1B).

FIG. 1C shows the end position of the contact element K, which is offset in the conveying direction by a distance H (stroke of the contact element) with respect to the starting position (FIG. 1A). The contact element is then moved back to its starting position and the counting process starts again.

In contrast to the conventional mechanical counters mentioned at the beginning, which can be referred to as passive counters, the method described above is an active counting method in which the contact element K is not stationary and is simply deflected by the printed products conveyed past, but rather by an independent movement is brought into suitable contact with the printed products. By appropriate design of the contact element and the specific circumstances The control of the product flow to be counted (variation of the forward and backward speed, if necessary variation of the stroke) can eliminate various sources of error and thereby achieve significantly better measurement results.

The method described is now to be examined in more detail theoretically with reference to FIG. 2. Although the process is not limited to regular processes, it is subsequently assumed that - as is usual with high-performance conveyor systems - all actions take place in a predefined temporal system cycle T (or a fraction or multiples of this cycle correlated to this) , where for example T = 1 / (number of copies per second) is defined. The following then applies to the local distance S between two successive printed products D _k , D _{k + 1 which are} conveyed at the speed v ₁ : $$\text{S = v₁ · T}$$

In addition, the behavior of the contact element K must also be matched to this system cycle. In the course of a work cycle, the contact element covers twice the stroke length H. If one assumes the simplifying assumption that the contact element is moved without delay on its way back and forth at a constant average speed v₂, the following applies: $$\text{2H = v₂ · T}$$

From equations (1) and (2) above it follows: $$\text{v₂ / 2H = v₁ / S}$$

In a real system, the distance S between two successive printed products is subject to certain statistical fluctuations, which also result in a significant source of error in conventional counting methods. In FIG. 2, the dashed lines show schematically that the majority of the printed products D _k , D _{k + 1} are within a range of ± ΔS (ΔS can be, for example, the standard deviation or mean quadratic variance) from the theoretical position ( the relations are chosen at random). In order to ensure that the contact element K also detects a printed product D ′ _{k + 1} that is behind the theoretical position by ΔS, the contact element K must be controlled in such a way that its forward movement with respect to the normal position of the printed product is triggered with a corresponding delay. On the other hand, this leads to the contact element having a "residue" a compared to a printed product D˝ _{k + 1} leading the normal position by ΔS, which is at least 2ΔS, and which it has to catch up on its forward path in order to be able to detect this printed product at all. If b denotes the distance that the contact element K travels on its forward path until it touches the printed product, the following can be written as a formula: $$\text{b / v₂ = (ba) / v₁}$$

Resolved after path b follows: $$\text{b = a / (1 - v₁ / v₂)}$$

In order for a given printed product to be caught by the contact element K, the distance b must be smaller than the stroke H: $$\text{H ≧ a / (1 - v₁ / v₂)}$$

Since, as already mentioned, a ≧ 2ΔS, the following also applies: $$\text{H ≧ 2ΔS / (1 - v₁ / v₂)}$$

$$\text{v₂ ≧ (1 + (4ΔS)/S) · v₁}$$

Algebraic transformation of the (Un) equations (3) and (7) gives the following conditions for the two system variables H and v₂ of the contact element K: $$\text{H ≧ S / 2 + 2ΔS}$$

$$\text{v₂ ≧ (1 + (4ΔS) / S) · v₁}$$

It should be emphasized that in the case of the above inequalities in the speed v₂ it is only the average speed of the contact element K during its forward and backward movement on the stroke path H. Of course, it is quite possible not to move the contact element at a constant speed. The contact element can, for example, be moved forward at a multiple of the average speed and then be returned more slowly, it being possible for rest phases to be provided both in the starting position and in the end position of the contact element. In a practical case, the movement of the contact element is more likely to be an accelerated movement (possibly unevenly). In a practical embodiment, it can equally well be provided that the contact element is returned to its starting position immediately after it has come into contact with the printed product, without completing the entire stroke, so that, depending on the deviation of the printed product from the normal position, the contact element moves differently.

Since the speed of the contact element cannot be chosen arbitrarily high for technical reasons, it has become practical Execution has proven an average speed v₂ of the contact element, which corresponds essentially to twice the speed v₁ of the product flow. In this case, the stroke H corresponds essentially to the mean distance S of the products in the shingled stream.

In the preceding explanations, an essentially linear forward and backward movement of the contact element was assumed. Although this corresponds to the movement preferred in the embodiment of the device, the method according to the invention is of course not limited to such movement sequences of the contact element. In Figure 3A, a further variant is shown in a schematic manner, the printed products are indicated for the sake of simplicity only by their linear speed v₁. The contact element K is moved on a non-linear (e.g. circular or elliptical) path 51 at the average speed v₂. This path can be open or also closed, so that in the second case the contact element K is not to be moved back in the same way, but can always be moved in the same direction and transferred to its starting position via a part of the path 51 not shown in the figure. This eliminates large differences in acceleration, which could have a negative effect on the contact element during back and forth movements and high conveying speeds. In this case too, the time cycle of the movement of the contact element K is preferably coupled to the superordinate system cycle T such that the contact element K executes a complete revolution during such a system cycle T.

In Figure 3B, several identical contact elements, for example K₁ to K₄, are moved at regular intervals on a circular track 61, for example. You will be at an angular velocity ω fixed, substantially transverse to the conveying direction of the printed products axis of rotation 62 rotated. The rotational speed ω and the radius R of the path 61 are chosen so that the tangential speed v₂ of the contact elements K₁ to K₄ in turn is higher than the conveying speed v₁ and the individual contact elements K₁ to K₄ based on a fixed viewer in turn follow in the system cycle T. .

In the following, some preferred counting devices based on the method described above will now be presented in more detail. The devices shown relate in particular to linearly moved contact elements, but can also be used in an analogous manner for other movement paths.

FIG. 4 initially shows a simple arrangement for linearly driving the contact element K. This is mounted, for example, on a linearly displaceably mounted slide 1, which is moved back and forth by a crank drive 2 operating in the system cycle. The printed products D located, for example, on a rotating conveyor belt 3 are preferably stabilized by a pressure roller 4 arranged in the region of the contact element K. It has been shown in practical tests that the counting accuracy is improved if this pressure roller 4 is not positioned directly opposite the contact element K, but slightly offset from it. Of course, the drive device shown only schematically in FIG. 4 is only to be regarded as a particularly simple one of many possible solutions. In particular, when the contact means (s) K move on an, for example, circular (open or closed) path (see FIGS. 3A and 3B), the arrangement of the contact means on the circumference of a stationary rotating wheel is conceivable, which wheel is coupled to the axis of the wheel Drive is moved. Of course, everyone must work together Drive devices that they allow operation of the counting device in accordance with the underlying method.

FIG. 5A shows a counting device according to the invention in a section along the conveying direction (indicated by an arrow), FIG. 5B shows the same device from behind in a section transversely to the conveying direction. The contact element is designed as a wedge-shaped shell 10 and slidably mounted on the carriage 1. As a result of the contact element running onto the rear edge of a printed product D, the former is displaced relative to the carriage 1 in the counter-conveying direction against the force of a return spring 12. FIG. 5A shows the normal position of the contact element 10 in dashed lines and the contact element displaced on the slide in a solid line. By moving the contact element, a microswitch 13 is actuated, the signal of which is led via a cable 14 to a counter (not shown) and registered there.

FIG. 5B shows how the carriage 1 is mounted on rails 11 arranged below the conveying means, while the wedge 10 projects into the plane of the printed products D. The conveying means for the printed products can consist, for example, of two conveyor belts (not shown) arranged in parallel, so that the counting device can be arranged in the space between them.

FIGS. 6A and 6B show a further embodiment of the device according to the invention, in which the contact element is designed as a pawl 20 which is rotatably mounted on the slide 1 about an axis 25. This embodiment has the particular advantage that there is no risk that the printed products will be displaced from their position in the scale flow by the contact element will. The pawl 20 shown in FIG. 6A at the moment of first contact with the printed product D is deflected by the latter to such an extent that the printed product is able to slide over it without being displaced (FIG. 6B) when the carriage 1 is advanced relative to the printed product. The deflected pawl 20 is pulled back into the rest position by a return spring 22.

Although in principle a microswitch arrangement analogous to FIG. 5 would also be conceivable, the deflection of the pawl is registered in this embodiment by a light barrier arrangement: a light beam emitted by an optical transmitter-receiver element 23 is reflected back by the pawl 20 when it is in the rest position ( Figure 6A) is located, while reflection of the light beam is prevented when deflecting the pawl, which is guided as a counting pulse via a cable 24 to a counter (not shown). Of course, the detector 23 can also be designed as a passive light-sensitive element which reacts to the light incident when the pawl is deflected.

In a further embodiment of the device according to the invention, the contact element is designed as a resilient bracket 30. This embodiment also has the advantage that the bracket is deflected from its rest position (FIG. 7A) by the pressure product D to be detected to such an extent that interference with the product flow is excluded (FIG. 7B). As a further variant, the contact between bracket 30 and printed product D is registered in that an existing magnetic circuit between bracket 30 and detector 33 is temporarily interrupted by the deflection of the bracket, whereupon a corresponding counting pulse is forwarded to a counter 35 via a cable 34. The counter 35 is only indicated schematically here and can be a local, for example electro-mechanical or electronic counter, or a central counter, in particular a computer control.

The above-described variants of the device according to the invention merely represent preferred embodiments thereof, and the invention is of course not limited to these. In particular, the preferred embodiment with a counting device located below the scale flow was shown in the preceding figures. This corresponds to the preferred arrangement since the trailing edges to be detected thereby rest on the conveying means and thus have a defined height. However, it is entirely within the scope of the invention to arrange the counting device above the scale flow, for example if, in a specific case, the scale flow is formed by overlapping printed products. There is also the possibility, to increase the accuracy, to record each printed product twice by moving the contact element at a correspondingly increased speed v₂. It is also evident that by arranging these devices at a given point in the production process and coupling them accordingly to a common counter, either the accuracy can be increased by redundancy or the operating frequency of the individual devices can be reduced.

Even if the printed products are usually conveyed in the form of a shingled stream in practice, the method according to the invention can of course also be used in other cases. The detection of printed products conveyed at irregular time intervals can also be realized with the method according to the invention by, for example, another element (for example a simple light barrier) making a rough detection of the Undertakes print products and accordingly activates the contact element according to the invention at irregular time intervals.

Claims (21)

1. Method for producing counting pulses by printed products conveyed in a scale flow, characterized by the cyclic repetition of the following method steps:

   a) a contact element (K) is moved out of a starting position substantially in the conveying direction of the printed products (D) at a speed (v₂), which at least over a partial range of the movement is higher than that (v₁) of the printed products (D),

   b) the contact element (K) is brought into contact with the trailing edge (F) of the printed products (D) moved passed and which is at the back in the conveying direction,

   c) a counting pulse is produced on contact between the contact element (K) and the trailing edge (F) of a printed product (D) and

   d) after producing the counting pulse, the contact element is moved back into its starting position.
2. Method according to claim 1, characterized in that the cyclic repetition takes place as a function of the average time interval (T) between two successive printed products (D_k, D_k+1).
3. Method according to one of the preceding claims, characterized in that the contact element (K) in each case during the average time interval (T) between two successive printed products (D_k, D_k+1) is advanced substantially linearly and parallel to the conveying direction by a given distance (H) from its starting position and is moved back into the starting position after contact with the trailing edge (F_k) of a printed product (D_k).
4. Method according to claim 3, characterized in that the predetermined distance (H) is at least equal to the sum of half the average local distance (S/2) between two successive printed products (D_k, D_k+1) plus twice the statistical standard deviation (2Δ S) of the printed products from the central position thereof.
5. Method according to claim 3 or 4, characterized in that the average speed (v₂) of the contact element (K) related to the predetermined distance (H) of its forward and return movement is at least equal to the product of the conveying speed (v₁) of the printed products (D_k) and the term (1 + 4 Δ S/S), in which S is the average local distance between two successive printed products (D_k, D_k+1) and ΔS is the statistical standard deviation of the printed products (D_k) from their central position.
6. Method according to one of the claims 3 to 5, characterized in that the predetermined distance (H) substantially corresponds to the average local distance (S) between two successive printed products (D_k, D_k+1) and the average speed (v₂) of the contact element (K) substantially corresponds to twice the conveying speed (v₁).
7. Method according to one of the claims 1 or 2, characterized in that during the average time interval (T) between two successive printed products (D_k, D_k+1), the contact element (K) is transferred from its starting position in the same direction over a closed path and back into its starting position.
8. Method according to one of the claims 1 or 2, characterized in that a plurality of contact elements (K) are moved on a closed path in such a way that their time interval, based on a fixed point, corresponds to the average time interval between two successive printed products (D_k, D_k+1).
9. Apparatus for counting printed products conveyed in a scale flow, characterized by a guidance means (11,51,61) for a contact element (K) located at least partly in the conveying direction and positioned in the vicinity of the printed products (D), by drive means (2) by means of which the contact element (K) over at least part of the guide means (11,51,61) is movable in the conveying direction and faster than the printed products (D) and which can be brought into contact with the trailing edge (F_k) of a printed product (D_k), by detecting means (13,23, 33) for emitting a signal on contact between the contact element (K) and the trailing edge (F_k) of a printed product (D), as well as by means (14,24,34) for transmitting the signal to a counting means (35).
10. Apparatus according to claim 9, characterized in that the guide means (11,51,61) is positioned below the conveyed printed products (D).
11. Apparatus according to claim 9 or 10, characterized in that the guide means is constructed as a substantially straight path parallel to the conveying direction of the printed products (D).
12. Apparatus according to claim 11, characterized in that the path has two parallel rails (11).
13. Apparatus according to one of the claims 9 to 12, characterized in that a sliding member (1) displaceably mounted on the guide means (11) is provided and on which is mounted the contact element (K).
14. Apparatus according to claim 13, characterized in that a crank drive (2) is provided by means of which the sliding member (1) on the path (11) can be moved out of its starting position by a predetermined distance (H) in the conveying direction and then back into the starting position.
15. Apparatus according to one of the claims 13 or 14, characterized in that on contact with a printed product (D), the contact element (10) is displaceable out of an inoperative position in the opposite conveying direction and into an operative position in opposition to the tension of a return spring (12) on the sliding member (1).
16. Apparatus according to one of the claims 13 or 14, characterized in that the contact element is constructed as a detent (20), which in the case of contact with a printed product (D) is pivoted about a pivot pin (25) substantially at right angles to the slide (1) from an inoperative position into an operative position.
17. Apparatus according to one of the claims 13 or 14, characterized in that the contact element is constructed as a bracket (30), which is deflectable from an inoperative position into an operative position on contact with a printed product (D).
18. Apparatus according to one of the claims 15 to 17, characterized in that the detection means is constructed as a microswitch (13), whose switching state can be influenced by transferring the contact means (10,20,30) from the inoperative into the operative position.
19. Apparatus according to one of the claims 15 to 17, characterized in that the detection means is constructed as a light barrier (23), whose switching state can be influenced by transferring the contact means (10,20,30) from the inoperative and into the operative position.
20. Apparatus according to one of the claims 15 to 17, characterized in that the detection means has a magnetic circuit (33), whose state can be influenced by transferring the contact means (10, 20,30) from the inoperative position into the operative position.
21. Apparatus according to one of the claims 9 to 20, characterized in that on the side of the scale flow opposite to the contact element (K) is provided a stabilizing device (4) by means of which the printed products (D) can be fixed in the scale flow during the counting process.

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