DE69400629T2 - Folder - Google Patents

Abstract

Chopper action folding apparatus for high speed printing or similar processing plant is shown diagrammatically in Figure 3. A conveyor (10) feeds signatures (12) towards a headstop (20). A vertical chopper blade (24) extending along the centre of the feed path is oscillated to initiate longitudinal folding of each signature as it is pressed downwards into a nip between longitudinal folding rolls (22) below the feed path which complete the folding process by drawing the signature downward. Brush or other braking means (26) slow or stop the approaching signatures before or as they reach the headstop so that they are folded without damage, the braking pressure being automatically regulated by control means (30) including infra-red or other position sensing means (32) which detects the relative positions of the headstock and approaching leading edge (14) of each signature for optimum operation. <IMAGE>

Description

The present invention relates to a folding device with impact element insert, in particular for automatic high-speed and high-performance operation at the output end of a printing system with continuous paper web feed or another processing system.

From EP-A-0 462 421 a folding apparatus according to the preamble of claim 1 is known.

The object of the present invention is to disclose a folding device which is reliable and economical, can be adjusted during operation, is particularly adapted to highly automated control systems for high-speed precision operation and whose operating parameters can be changed easily and quickly by remote control.

The folding device with impact element insert according to the invention contains the following components:

a) a transport device for transporting continuously supplied, successively arranged pre-folded or unfolded printed products consisting of at least one sheet along a feed path;

(b) a travel limiter having a stop face, which can be aligned in use along that path, to limit the forward movement of any printed product along that path;

c) a striking element which is guided in a swinging manner so that it can move in a folding area which extends in the direction of movement is located upstream of the stop face of the feed path, overlaps with the feed path or moves away from it again;

d) a pair of folding elements which form a fold directly adjacent to this area, in which the printed product, which is pressed with the outside into this fold, is received and through which it is transported away;

e) an impact element drive device which drives the impact element in a phase-shifted manner to transport each printed product into this area in order to initiate folding or further folding of the printed product by pressing the printed product into the fold;

f) a braking device for largely or completely braking the feed movement of each printed product in this area when it approaches or reaches the stop face (18), so that the impact element can act on the printed product;

g) a control device comprising a position sensor device in or near the folding area, which in operation determines the relative position of the stop face to the approaching or stopped front edge of each successive printed product in this area, as well as control devices which automatically adjust the effect of the braking device on the printed products used in dependence on the display of the sensor device, whereby the impact element acts on each printed product when it is optimally aligned in this area, with the front edge positioned towards the stop face in such a way that the printed product is not damaged and is folded effectively and precisely.

Preferably, the sensor device comprises a pair of position sensors at respective positions which are arranged at a distance from one another to the side of the feed path and react independently of one another to the relative position of the respective stop face and printed product front edges arranged at a distance from one another, whereby their individual displays are also automatically compared with one another in order to determine an inclination of the front edges or the stop face.

The sensor device or each of its sensors contains an infrared detector on one side of the path and a light source on the other side, the detector and the light source being aligned in the longitudinal direction of the feed path so that the extent to which the light reaching the detector is covered is a direct function of the relative alignment.

The infrared detector may comprise a longitudinally extending array of individual detector cells, the number of cells activated at a given time being a direct function of the relative orientation.

The braking device can expediently contain one or more brush elements which act in a known manner on an outer side or on outer sides of the printed products in the folding area, wherein the regulating device serves to adjust the pressure of the brush element or elements on this outer side or these outer sides in such a way that their friction braking effect on the outer side or the outer sides changes.

The regulating device can further comprise a timing unit which, in addition to determining the relative alignment of the stop face to the leading edge, also enables the speed at which the leading edges approach the stop face and/or the rate at which the leading edges are braked by the braking device, whereupon the latter are readjusted in a feedback process.

An embodiment of the present invention is explained in more detail below with reference to the accompanying drawing. In the drawing:

Fig.1 is a perspective diagram of a folding apparatus, with some parts omitted for clarity;

Fig.2 a corresponding diagram representation, in which the position sensor device is also shown; and

Fig.3 is a longitudinally sectioned diagrammatic representation of a part of this apparatus.

The folding machine with impact element insert essentially comprises conventional folding mechanisms, the basic components of which are shown in Fig.1. A number of rotatably driven upper and lower belts 10 arranged parallel to one another at a distance, which moving from left to right in the drawing, continuously transport printed products 12 arranged one behind the other, which usually originate from the delivery end of a high-speed continuous paper web printing plant. The printed products 12, which are shown as examples, have already been cut in conventional cylinder web handling devices of the printing plant and folded once transversely to the feed direction, the folded transverse edge 14 of each printed product being the respective leading edge in the feed path direction. Each printed product can consist of one or more sheets and does not necessarily have to be pre-folded if only one fold along the transport direction is required. However, it can also be pre-folded more than once before it reaches this machine.

The latter folding shape is produced as soon as each printed product reaches a folding area 16, which is marked in Fig. 1 by the arrow 16 and whose downstream end is formed by the stop face 18 of a movement limiter 20 aligned transversely to the feed path. The movement limiter 20 has cuts through which the belts 10 run, while the fed printed products 12 do not fit through.

Exactly in the direction of movement above the movement limiter 20 and in a central position exactly below the feed path, a pair of folding rollers 22 are provided in the folding area 16, which limit a central bend in the longitudinal direction of the feed path and are rotatably driven in such a way that the sheet material pressed into the bend is grasped by them and pulled out of the feed path in order to be transported downwards onto another conveyor device (not shown).

A vertical striking blade 24 cooperates with the rollers 22. The blade 24 is guided in such a way that it can move vertically, with its movement overlapping with or away from the feed path. It is precisely aligned with respect to the bend between the rollers 22 and is driven by conventional drive means not shown in the drawing, which is usually an arrangement with a rotating crankshaft and a connecting rod. Other types of striking elements can also be used, for example striking elements that can be moved up and down or striking elements that carry out a type of chopping movement. The impact blade 24 moves out of phase with the printed product advance so that it moves downward to engage the top of each printed product when it is fully in the folding area 16, with the front edge 14 coming to rest directly on or very close to the stop face 18. The longitudinal folding of each printed product is initiated by the lower edge of the blade 24 pressing the bottom of the printed product into the roll fold. As soon as it is caught in the roll fold, it is pulled downward and the fold is completed by the pressure exerted by the rollers 22. In the meantime, the impact blade 24 has been moved back up to the starting position for the next cycle.

A conventional high-speed paper web printing press operates at an average speed of over 12 mi and produces over 72,000 printed copies per hour. It is therefore understandable that all the continuously supplied printed products 12 are transported quickly away from the press and It is also important that any adjustments that may be necessary can be carried out easily and accurately while the system is running at full speed, and that this can be done from a remote control unit with complete and easy-to-understand displays of operating parameters and clear warnings of any faults or malfunctions. Any malfunction at the output end could result in the entire printing line being shut down, resulting in loss of time and materials.

During the folding process itself, each printed product 12 must be brought almost or completely to a standstill when it reaches the folding area 16 so that it can be folded and removed from the feed path without being damaged by violent impact with the movement limiter 20. This also ensures that the folds are made correctly and accurately. For this purpose, the apparatus contains a braking device (not shown in Figs. 1 and 2) which has brushes 26 arranged in the folding area in order to exert friction on the upper and possibly also on the lower side of the printed product between the belts 10 on each side of the striking blade 24. The friction caused by the brushes 26 causes the printed products to be stopped or almost stopped when the folding process is carried out. The braking pressure can be adjusted by changing the brush pressure using a servo unit 28 provided for each brush or brush group. In practice, frequent, precise adjustment of the braking force is necessary, since the feed speed of the conveyor belts 10 can change, different types of paper and/or ink are used and the thickness, ie the number of the sheets changes, which affects the response of the printed products themselves to the friction. In addition, the brushes are subject to wear. The brushes 26 have bearing springs, which protects them from damage if a number of printed products or sheets accumulate undesirably.

The impact blade 24 can also contribute to the braking effect. In this case, it can be considered as part of the braking device, since it also acts by friction on the top of the printed product while it may still be moving, and this is another factor affecting the braking force required. In some known types of folders, the impact blade and/or the other impact or folding elements serve as the only braking devices. The braking effect can then be regulated by changing the phasing of their folding movement.

In other known designs, other types of braking devices have been used, for example air braking using vacuum housings acting on the printed product in the folding area, the braking effect being adjusted by changing the vacuum level present in them.

The apparatus further comprises a control device 30, which includes position sensor means as diagrammatically shown in Figs. 2 and 3.

These sensor devices comprise position sensor devices comprising a pair of infrared detector units 32, which in this embodiment are located directly below the feed path at the upstream end of the folding area 16 and just below the stop face 18 of the travel limiter 20, extending longitudinally downstream from that face. The units 32 are arranged laterally at a distance from one another on either side of the center of the feed path.

Each unit 32 comprises a series of individual infrared detectors, for example 14, arranged at a distance of 1 mm along the feed path.

An infrared light source 34 is arranged above the feed path relative to each unit 32. Its rays are directed directly downward and illuminate the entire area of the respective units 32 as well as a portion of the surrounding area. In some embodiments, the units 32 are preferably arranged above the feed path while the light sources are located below the feed path.

The signal from each individual cell of each unit 32 is passed to a signal module 34 of the control unit 30 where the signals are processed. The output signal is passed through the control module 36 to activate the servo units 28 which adjust the braking pressure of the brushes 26 and also to produce a visual indication of the operating conditions on a display screen of the control station 38.

A group of individual infrared cells of the units 32 located on the left side determines the position of the stop face 18 and also checks whether this face is at a right angle to the feed path or has an angular deviation, which is made possible by the presence of two units arranged laterally at a distance from each other.

At the same time, the remaining cells of each unit respond to the position of the leading edge of each printed product as it is decelerated and approaches the front face 18, the number of cells not covered by the light source 34 by the motion limiter 20 or the respective printed product 12 providing a measurement of the relative position of the front face 18 to the leading edge 14. The closest approach of each leading edge 14 to the front face 18, where they may even touch, is determined in synchronization with the timing of the actuation of the striking blade 24, typically when the blade is a few degrees from its bottom dead center. As the printed product is pulled through the rollers 22, the sensors detect the disappearance of the trailing edge of the printed product, which provides further information about the sequence of operation.

In addition, the rate at which the successive cells are covered by the moving leading edge 14 as it moves past each module, together with a timing unit of the processing module 34, can provide an indication of the speed at which the printed product is moving toward the travel limiter 20 and the rate of deceleration as it is brought to a near or complete stop.

If all cells of both units are covered almost instantly, which is an extreme case, this is an indication that the braking device is not working effectively and the printed product is being has impacted the travel limiter 20, possibly causing damage and thus a faulty folded copy. The braking force is automatically increased until this malfunction is corrected, the control device 30 preferably storing and comparing the signals from successive printed products to determine the rate and effectiveness of the automatic adjustments made to the braking device.

If during the folding cycle no cells other than those covered by the movement limiter 20 are covered, this is an indication that the printed product has not reached the units 32 because either the feed was not carried out correctly or because too high a braking force was used. In this case too, an automatic correction is carried out and, if necessary, a visual display is generated on the screen of the control station 38.

Another reason for incorrect folding is that the printed products do not arrive in a line or at an angle in the folding area, or that individual sheets or pages are incorrectly aligned. The use of two detector units 32 arranged at a distance from each other enables the correct alignment of the front edge to be checked. If more cells of one unit are covered than the other, the front edge is at an angle or incorrectly aligned.

Preferably, means are also provided for determining the intensity of the light reaching the units 32 during operation and for increasing the intensity up to a limit value if necessary. This compensates for wear of the lamps and/or the sensor units 32 as well as possible contamination, for example by dust, as well as differences in the type and thickness of paper, the surface quality, the printing, etc.

The control module 36 may include means for determining the speed at which the operating parameters are changed, and in particular the speed at which the brush pressure is changed, depending on the significance of the error detected. A significant deviation detected by the units 32 will result in a more extensive and rapid initial adjustment of the servo units 28. However, as the deviation decreases, the adjustment becomes much more precise in order to prevent the control loop from oscillating as much as possible. Comparing successive readings from the detector units 32 and averaging them also contributes to the accuracy and effectiveness of the fine tuning.

While the apparatus according to the invention has so far been described in connection with brush braking devices, the braking can also be carried out by other devices, such as a vacuum housing braking device of the type described above and/or by adjusting the braking effect exerted by the striking blade or another striking element and/or folding elements of the apparatus or by a combination of these braking elements and braking effects.

Of course, other position sensor devices than the infrared units described can also be used.

In some manufacturing processes, it may not be necessary to create a fold using a specific folding device with a striking element insert that is part of a printing system or another type of processing system. In this case, devices can be provided to lift the movement limiter 20 out of the feed pad and to hold the striking blade 24 in its upper position so that the printed products are transported unchanged through the folding area 16. In this case, it can still be useful to keep the detector units 32 in operation, since they can detect any slant in the feed of the printed products transported past them and also give an indication of their transport speed at this point.

The display, which is determined from the output signals of the sensor unit and from further data from the control device and other systems of the machine and which the operating personnel receive at the control station 38, is preferably shown in easily understandable graphical format or in image form together with numerical data and can show how close the leading edge 14 comes to the movement limiter 20, what angular position is assumed, what transport speed prevails, whether or not printed products are present, to what extent adjustments are carried out by the automatic control circuit, etc.

Claims (12)

1. Folding device with impact element insert, containing a) a transport device (10) for transporting continuously supplied, successively arranged pre-folded or unfolded printed products (12) consisting of at least one sheet along a feed path; b) a movement limiter (20) having a stop face (18) which can be aligned on said path during operation to limit the forward movement of each printed product (12) on said path; c) an impact element (24) which is guided in a swinging manner so that it overlaps with the feed path or moves away from it again in a folding area (16) which is located upstream of the stop face (18) of the feed path; d) a pair of folding elements (22) which form a fold directly adjacent to this area, in which the printed product (12), which is pressed with the outside into this fold, is received and through which it is transported away; and e) an impact element drive device which drives the impact element in a phase-shifted manner to transport each printed product (12) into this area (16), to initiate folding or further folding of the printed product by pressing the printed product into the fold; f) a braking device (26) for largely or completely braking the forward movement of each printed product (12) in this area when it approaches or reaches the stop face (18) so that the impact element (24) can act on the printed product (18); characterized in that the apparatus further comprises the following devices: g) a control device (30) containing a position sensor device (32) in or near the folding area (16) which, during operation, determines the relative position of the stop face (18) to the approaching or stopped front edge (14) of each successive printed product (12) in this area, as well as control devices (36, 28) which automatically adjust the effect of the braking device (26) on the printed products (12) used in dependence on the display of the sensor device (32), whereby the impact element (24) acts on each printed product (12) when it is optimally aligned in this area (16), the front edge (14) coming to lie relative to the stop face (18) in such a way that the printed product (12) is not damaged and is folded effectively and precisely. 2. Apparatus according to claim 1, characterized in that the sensor means comprises a pair of position sensors (32) which are arranged at respective locations laterally at a distance from the feed path and react independently of one another to the relative position of the respective parts of the stop front side (18) and the printed product front edges (14) arranged at a distance from one another. 3. Apparatus according to claim 2, characterized by a device (34) for automatically comparing the individual output signals from the position sensors (32) in order to determine a tilt position. 4. Apparatus according to claim 2 or 3, characterized in that each sensor (32) includes an infrared detector on one side of the feed path and a light source (34) on the other side. 5. Apparatus according to claim 4, characterized in that the detector (32) and the light source (34) each extend in the longitudinal direction of the feed path so that the degree to which the light reaching the detector is blocked is a direct function of the relative orientation. 6. Apparatus according to claim 5, characterized in that the detector (32) comprises a longitudinally extending row of individual detector cells, the number of cells activated at a given time being a direct function of the relative orientation. 7. Apparatus according to claim 6, characterized in that an end group of each row of cells serves to Determine the position and lateral alignment of the stop face (18). 8. Apparatus according to claim 6 or 7, characterized in that cells in each row serve to determine the position of the front edge (14) of each printed product (12) relative to the position of the stop face (18). 9. Apparatus according to claim 6, 7 or 8, characterized in that it includes timing units (34) operatively responsive to the rate at which the successive cells of each row are covered by the moving leading edge (14) to provide an indication of the speed at which the printed product (12) is approaching and/or decelerating. 10. Apparatus according to one of the preceding claims, characterized in that the braking device contains at least one brush element (26) which acts on the top or tops of the printed products (12) in the folding area (16), the regulating device serving to adjust the pressure exerted by this element or these elements and thus to change the braking effect used. 11. Apparatus according to one of claims 1 to 9, characterized in that the braking device contains vacuum housings which, during operation, act on the printed product (12) in the folding area, the regulating device (36) serving to adjust the vacuum level and thus to change the braking effect used. 12. Apparatus according to one of the preceding claims, characterized in that the movement limiter (20) and the impact element (24) can optionally be mounted remote from the feed path, so that the printed products (12) can be transported through the folding zone (16) without folding taking place, the position sensor device (32) serving to monitor their transport through this zone.