EP2343260B1 - Method for operating a blade folder and a blade folder - Google Patents

Description

The present invention relates to a method for controlling a square-folding device of a rotary press for folding flat products from a continuous web, comprising a pair of parallel folding rollers defining between them a gap, a movable folding blade for forcing a flat product into the gap, a means for adjusting the spacing between the two folding rollers and a control device of the adjusting means adapted to control the adjusting means in a production mode for maintain a proper spacing during production.

EP 2 112 111 discloses a method of controlling a right-angle fold device according to the preamble of claim 1.

The object of the present invention is to provide a method for controlling a right-angle crease device making it possible to limit the risk of jamming.

For this purpose the invention relates to a control method according to claim 1.

Other embodiments are defined in claims 2 to 8.

Another object of the invention is to provide a right-angle folding device for a rotary press for folding flat products, comprising a pair of parallel folding rollers defining between them a gap, a movable folding blade adapted to force a flat product in the gap, an automated gap setting means adapted to adjust the spacing between the two folding rollers according to a thickness value of the flat product, and a control device of the adjusting means adapted and programmed to implement a method according to the invention.

• figure 1 est une vue schématique d'une plieuse d'une presse rotative ;
• figure 2 est une vue schématique de côté d'un dispositif de pli d'équerre de la plieuse de la figure 1 ; et
• figure 3 est un graphique illustrant l'écartement entre deux rouleaux de pliage du dispositif de pli d'équerre en fonction du temps lors de la mise en oeuvre d'un procédé de commande selon l'invention.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which:

• figure 1 is a schematic view of a folder of a rotary press;
• figure 2 is a schematic side view of a right-angle folding device of the bending machine of the figure 1 ; and
• figure 3 is a graph illustrating the spacing between two bending rolls of the bend device as a function of time during the implementation of a control method according to the invention.

On the figure 1 is represented a folder according to the invention, designated by the general reference 2. The folder 2 is adapted to receive a continuous strip of material, or several continuous strips of material superimposed, forming a continuous strip 4 of flat products 6, to fold the continuous strip 4, and to separate and fold the flat products 6. The folder 2 is part of a printing press, including rotary, not shown as a whole on the figure 1 . The elements of the folder 2 will be described in the order in which the continuous strip 4 of flat products 6 passes through this folder 2.

The folder 2 comprises a longitudinal folding cone 8 with two pinch rollers 10 adapted to produce a first fold, a longitudinal fold, of the continuous strip 4 of flat products 6.

The folder 2 comprises motorized call rollers disposed downstream of the cone 8 to drive the continuous band 4 by maintaining it in tension.

A first pair of rollers 12 is located immediately downstream of the pinch rollers 10 and controls the tension and the call of the continuous strip 4 on the cone 8.

The folder 2 may comprise a pair of transverse perforation rollers 14 and a pair of longitudinal perforation rollers 16. The transverse perforation rollers 14 facilitate the formation of a second fold, a transverse fold, and the longitudinal perforation rollers 16 facilitate the formation of a third fold, a fold of square. The perforation rollers 14, 16 can be activated or deactivated depending on the type of production to be carried out.

A second pair of rollers 18 located downstream of the perforation rollers 14, 16 controls the tension and the call of the continuous band 4 at the level of the perforation rollers 14, 16.

The folder 2 comprises a cutting cylinder 20 equipped with a saw frame and adapted to cut the continuous strip 4 transversely and separate it into a succession of flat products 6 separated. The flat products 6 are then driven by a transfer cylinder 22 together with a bank of cords 24 which route them to a set of folding cylinders 26 which produces the second fold, the transverse fold.

Downstream of the set of folding rolls 26, the folder 2 comprises a right-angle folding device 28. This right-angle folding device 28 is adapted to make a square fold of the flat product 6.

The angle fold device 28 is shown in more detail on the figure 2 . It comprises a table 29 for receiving the flat products 6 provided with a slot, a folding blade 30, a pair of parallel folding rollers 32 defining between them a gap 34 facing the slot of the receiving table 29 and a adjusting means 36.

The folding blade 30 is movable in alternating translation through the slot of the receiving table 29, to force flat products 6 received on the reception table 29 through the slot and in the gap 34 between the two rollers. The folding rollers 32 are motorized to drive the flat product 6 between them. The folding blade 30 and the folding rollers 32 cooperate to form the square fold.

The adjusting means 36 has the function of modifying the spacing between the folding rollers 32. It comprises two adjustment assemblies 37 each disposed at one end of the folding rollers 32. On the figure 2 only a set of adjustment 37 is visible and will be described later. The other set of adjustment 37 is analogous and the adjustment sets 37 are synchronized.

The adjustment assembly 37 shown on the figure 2 comprises a motor 38, a screw 40, a spring 42 and a pair of rotating arms 44.

The arms 44 are rotatably mounted about respective parallel axes A.

Each folding roller 32 is rotatably mounted at one end of a respective arm 44, about an axis B parallel to the axis A of rotation of the arm 44. The rotation of the arms 44 causes a change in the spacing between the arms. folding rollers 32.

The spring 42 is disposed between the ends of the arms 44 opposite to the folding rollers 32 and urges them in the direction of approaching the folding rollers 32.

The screw 40 is provided with nuts 45 serving as a rotational stop for the arms 44 in the direction of approaching the folding rollers 32. The spring 42 biases the arms 44 in abutment against the nuts 45.

The position of the nuts 45 defines the spacing between the folding rollers 32. The rotation of the screw 40 changes the spacing between the nuts 45 and thus the adjustment of the spacing between the folding rollers 32. The rotation of the screw 40 also modifies the compression of the spring 42.

The motor 38 is coupled to the screw 40 so that the motor 38 can drive the screw 40 to modify the position of the nuts 45 and thus the adjustment of the spacing between the folding rollers 32.

In operation, the folding blade 30 forces the flat product 6 between the motorized folding rollers 32 which drive the flat product 6 between them by forming a square fold. The passage of the flat product 6 between the folding rollers 32 is carried out against the spring 42 which opposes the spacing of the folding rollers 32. The pressure exerted by the folding rollers 32 therefore depends on the adjustment of their spacing.

The folder 2 further comprises a control device 46 adapted to control the adjusting means 36. This control device 46 comprises a first pressure sensor 48 at the first pair of call rollers 12 and / or at the level of the second pair of rollers 18, a second pressure sensor 50 at the folding rollers 32, a processor 52 and a man-machine interface 54.

The first and second pressure sensors 48, 50 are adapted to measure the pressure applied on the continuous strip 4 by the first and / or second pair of rollers 12, 18 and on the flat product 6 by the folding rollers 32 , respectively. The processor 52 is programmed to control and regulate the adjustment means 36 from the measurements made. The human-machine interface 54 allows a user to specify manual control instructions to the controller 46.

The operation of the folder 2, and in particular a method of controlling the folder 2, are described below.

In the folder 2, the continuous strip 4 is folded longitudinally at the cone 8, is then perforated and cut into a plurality of flat products 6 which are folded transversely relative to the first fold. The flat products 6 then pass into the square fold device 28 where they are folded a third time along a line parallel to the first fold.

A slight change in the thickness of the continuous strip 4 at the cone 8 results in a change in the thickness four times greater at the folding rollers 32 of the angle fold device 28. It is desirable to be able to adjust the gap 34 between the two folding rollers 32 according to the thickness of the continuous strip 4 in order to avoid a jamming of the square fold device 28 at the level of the folding rollers 32, for example as a result of too much spacing does not allow the folding rollers 32 to properly swallow the flat products 6 engaged between the folding rollers 32 by the folding blade 30.

For this purpose, the folder 2 implements a control method which is controlled by the control device 46. According to this control method, the control device 46 controls the adjustment means 36 selectively in a production start mode and in a production mode.

The mode of production is implemented in steady state or permanent production.

In the production mode, the first and second pressure sensors 48, 50 measure the pressure applied on the continuous strip 4 exerted by the first and / or second pair of rollers 12, 18 and on the flat product 6 exerted by the folding rollers 32, respectively. The measured pressure values are transmitted to the processor 52 which determines a thickness value of the continuous strip 4 at the first and / or second pair of rollers 12, 18 and the spacing between the two folding rollers 32. The processor 52 determines whether the spacing between the two folding rollers 32 is too large or too small relative to the thickness of the continuous strip 4 at the level of the first and / or second pair of rollers 12 18 and controls the adjusting means 36 so that the distance between the two folding rollers 32 is adjusted according to the thickness of the continuous strip 4 at the level of the first and / or second pair of rollers. 12, 18. The production method makes it possible to automatically regulate the spacing between the two folding rollers 32 without human intervention and is adapted for continuous operation of the folder 2.

In a variant, the control device 46 does not perform a pressure measurement, but a user chooses, for example, from a table of values pre-recorded thickness, the thickness value of the corresponding flat product 6, by means of the man-machine interface 54. The control device 46 controls the adjustment means 36 so that the distance between the two rolls of folding 32 is adjusted according to the thickness value specified by the user.

The production start mode is implemented transiently at the start of each new production.

A production is defined in particular by the quality of paper (format, grammage, thickness) and by the processing of the continuous strip 4 and the flat product 6 (number of superimposed bands, number and positions of the folds, production accumulated and not accumulated, number of pages ...). The modification of a production parameter modifies the characteristics of the flat products 6 at the angle fold device 28.

"New production" means a production beginning after a change in production resulting from a change in the production parameters or the production of a splice, or the restart of a production after a stoppage of the rotary press, by example after a tape break.

At the start of a new production, the control device 46 is configured to maintain between the folding rollers 32, in production mode, a spacing adapted to the new production, since it receives the information relating to the new production. and / or the measurements for the regulation of this spacing taken on the continuous strip 4 corresponding to the new production which begins to circulate in the folder 2.

According to the invention, in the production start mode, the control device 46 controls the spacing of the folding rollers 32 to a determined fixed reference value.

The two folding rollers 32 assume a determined position with a reference gap regardless of a pressure measurement exerted by the call rollers 12, 18 or a manually specified gap value for the second production.

The production start mode is maintained for a specified duration. This duration is preferably chosen so that the production mode, which follows the production start mode, only starts when the first flat product 6 of the new production arrives or is passed at the level of the folding rollers 32. The duration typically corresponds to the passage time of about 200 flat products 6 at the folding rollers 32.

On the figure 3 is shown the spacing between the two folding rollers 32 as a function of time. In the period between times t ₀ and t ₁ the bender 2 processes a first production. The spacing between the two folding rollers 32 is adapted to the flat products 6 of this first production and the control device 46 is maintained in the production mode. At time t ₁ , production is changed and a second production is made, and between time t ₁ and time t ₂ control device 46 is maintained in the production start mode. The gap corresponds to the reference gap E ₀ . After the instant t ₂ , the control device 46 resumes the production mode and the spacing is adjusted to the thickness of the flat product 6 of the second production. The thickness of the flat product 6 is determined either by the pressure measurement or manually by means of the man-machine interface 54.

The reference gap is chosen to allow the right-angle fold device 28 to swallow the flat products 6 of the production preceding the new production, despite the changes in treatment (number of pages, thickness, production accumulated or not accumulated) .

The reference gap may be less than the gap required for the second production. The reference gauge for the second production may be the distance from the first production.

Alternatively, the reference gap is a minimum gap for the folding rollers 32, corresponding to the minimum gap setting between the folding rollers 32. This minimum gap is for example about 0.1 mm.

In another variant, the reference gap is not limited to a single reference gap value, but several reference gap values can be envisaged. During the production start mode, the reference gap value is adopted which is, among the different reference gap values, the most suitable for the thickness value of the flat product 6 of the production processed during the period. directly before this period of production start mode.

The control method according to the invention is particularly advantageous in cases where the flat products 6 of the new production has a thickness greater than that of the flat products 6 of the previous production, so that the remainder of flat products 6 intended for the Previous production might not be swallowed properly between the folding rollers 32.

• lorsque l'on passe d'une production non-accumulée à une production accumulée,
• lorsque l'on passe d'une production avec papier de faible grammage à une production avec papier de gros grammage ou
• après une casse de la bande continue 4, notamment lors du passage de l'épissure, c'est-à-dire de la partie où deux morceaux de bandes continues 4 sont raboutés, dans le dispositif de pli d'équerre 28.

The control method according to the invention is particularly advantageous:

• when we move from unaccumulated production to accumulated production,
• when moving from low-weight paper production to heavy-paper production
• after breakage of the continuous strip 4, in particular during the passage of the splice, that is to say the part where two pieces of continuous strip 4 are spliced together, in the square fold device 28.

Claims (9)

1. Method of controlling a blade folder (28) of a rotary press for folding flat products (6) dispensed from a continuous strip (4), comprising a pair of parallel folding rollers (32) defining a gap (34) between them, a displaceable folding blade (30) for forcing a flat product (6) through the gap (34), a means (36) for adjusting the distance between the two folding rollers (32) and a device (46) for controlling the adjusting means (36) configured to control the adjusting means (36) in a production mode in order to maintain an appropriate distance during a production run, wherein at the start of a new production run, the control device (46) runs a production start-up mode during which it controls the means (36) for adjusting distance in order to set the distance to a given reference value, followed by the production mode, during which it controls the adjusting means (36) in order to set a distance adapted to the new production run, characterised in that in production mode, the control device (46) controls the adjusting means (36) as a function of a thickness measurement of the continuous strip (4) on a level with intake rollers (12, 18) or as a function of a measurement of the pressure exerted on the continuous strip (4) by intake rollers (12, 18) in order to drive the continuous strip (4).
2. Control method as claimed in claim 1, in which the reference value is maintained for a given period, corresponding, for example, to the passage of approximately 200 flat products (6) between the two folding rollers (32) .
3. Control method as claimed in claim 1 or 2, in which the reference value corresponds to a minimum distance.
4. Control method as claimed in claim 1 or 2, in which the reference value corresponds to the distance of the preceding production run.
5. Control method as claimed in claim 1 or 2, in which the reference value is lower than the distance value of the new production run.
6. Control method as claimed in any one of claims 1 to 5, in which the production start-up mode is run when there is a change of production and/or on re-starting the rotary press after a stoppage.
7. Control method as claimed in any one of claims 1 to 6, in which, in production mode, the control device (46) controls the adjusting means (36) as a function of a thickness measurement of the flat products (6) on a level with the folding rollers (32).
8. Control method as claimed in any one of claims 1 to 7, in which, in production mode, the control device (46) controls the adjusting means (36) as a function of a measurement of the pressure exerted on the flat products (6) by the folding rollers (32).
9. Blade folding device (28) of a rotary press for folding flat products (6), comprising a pair of parallel folding rollers (32) defining a gap (34) between them, a displaceable folding blade (30) configured to force a flat product (6) through the gap (34), an automated means (36) for adjusting distance configured to adjust the distance between the two folding rollers (32) as a function of a thickness value of the flat product (6), and a device (46) for controlling the adjusting means (36) configured and programmed to implement a method as claimed in any one of the preceding claims.

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