EP2489616A2 - Feeder for a printer and method of operating such - Google Patents

Abstract

The feeder (1) has a suction device (10) for withdrawing sheets from a sheet stack (4) and a transport unit (11) for conveying the sheets in sheet transport direction. The sheet detection units (17) are arranged between the suction device and transport unit. The detection units and a controllable drive (13) of suction device are connected with a machine controller (14) and the drive is controlled based on measurement result of detection units according to control rules for the drive stored in suction device. An independent claim is included for method for operating feeder.

Description

The invention relates to a feeder according to the preamble of claim 1 and to a method of operating an investor according to claims 9 and 10, respectively.

State of the art

Pocket folding machines and Schwertfalzmaschinen are known from the prior art. The combination of pocket folding machines with Schwertfalzmaschinen is common as Kombifalzmaschine. In this process, parallel folds are folded in pocket folders and cross breaks in the subsequent knife folders. The sheet passes through at least the following stations in the feed-through direction of the combination folding machine: feeder, transfer table, pocket folder, knife folder, delivery arm. In the feeder area, it is important that sheets are pulled off the pile of sheets as intended and are not provided by the transfer table as multiple sheets.

The construction of a Taschenfalzmaschine with a variety of Taschenfalzwerken goes out of the DE 10 2004 041 471 A1 out. A respective pocket folder consists of a folding pocket and three folding rollers, which are arranged in two pairs of folding rollers. From the DE 29 40 360 A1 is a single sword folding machine for folding of printed and pre-folded sheet known. Combination folding machines combine pocket folders and knife folders. Here are folded in a first folding station in Taschenfalzwerken parallel breaks and in a subsequent folding station in Schwertfalzwerken cross breaks. The DE 10 2006 055 301 A1 shows Kombifalzmaschinen with a plurality of Taschenfalzwerken and nachranging arranged Schwertfalzwerken. From the DE 10 2008 048 287 A1 For example, a folding machine is used for shovel feeding and shallow folding.

For multiple sheet control, often referred to as double sheet control, numerous solutions are known from the prior art. For example, the DE 295 02 272 U1 a device for detecting double sheets to investors of sheet-fed presses. If a double sheet is detected, the double sheet is sucked through a suction nozzle, a signal is generated for the machine operator and he must remove the double sheet. In such double-sheet locks, the printing machine is brought to a standstill upon detection of a double sheet and must be restarted after removing the double sheet. This reduces the production capacity of the printing machine.

The DE 40 05 910 C2 In contrast, shows a feed table of a printing press with a double sheet recognition and a device for separating out double sheets. If a double sheet is detected, it is discharged by means of a switch. Although this procedure makes it possible that the printing machine does not have to be stopped, however, the double sheet still represents waste. Also, due to the gap in the sheet flow in downstream units (eg display, stacking), process disturbances may occur.

task

The object of the present invention is therefore to provide a feeder for a printing machine and to describe a method for operating such an investor, wherein the o.g. Fixed problems, so increased productivity and reduced paper waste.

This object is achieved by an investor according to claim 1 and by a method for operating an investor according to claim 9 or 10.

The feeder according to the invention is suitable for a printing machine, such as a printing press, a folding machine, a punching machine or a mailing machine. The feeder has a machine control, a suction device for withdrawing a sheet from a stack of sheets which has at least one Saugelelement moved with a transport speed, a transport device for further transport of the sheet in the sheet transport direction, wherein the transport device can be configured, for example, as a suction belt table or bias belt table. The withdrawn sheet may in particular be the uppermost sheet but also the lowermost sheet. In essence, between the suction device and the transport device, a device for multiple sheet detection is arranged. Such devices for the detection of double sheets usually have optical, mechanical, inductive or capacitive sensors or ultrasonic sensors to realize a non-contact monitoring. Advantageously, the suction device has a controllable drive and this controllable drive as well as the device for multiple sheet detection are signal technically connected via data lines with the machine control. The controllable drive can be controlled as a function of the measurement result of the device for multiple sheet recognition and is controlled as a function of the measurement result.

• Wird von der Einrichtung zur Mehrfachbogenerkennung kein Mehrfachbogen detektiert, so wird der Antrieb der Saugeinrichtung normal weiterbetrieben.
• Wird von der Einrichtung zur Mehrfachbogenerkennung ein Mehrfachbogen detektiert, so wird die Ansteuerung der Saugeinrichtung verändert.

In a particularly advantageous and therefore preferred development of the invention, control rules for the drive of the suction device are stored in the machine control system, a control rule being associated with a respective possible measurement result of the device for multiple-arc detection:

• If no multiple sheet is detected by the device for multiple sheet detection, then the drive of the suction device continues to operate normally.
• If a multiple arc is detected by the device for multiple sheet detection, the control of the suction device is changed.

With this feeder according to the invention, machine stops are advantageously no longer required in order to have multiple sheets removed manually by the machine operator. Also no ejection of detected double sheet is required and thus no switch, in which a deflection of the sheet must be made. Rather, all sheets can be further processed in the printing machine. As a result, both the waste is reduced and allows a higher productivity of the printing machine.

If a multiple sheet is detected by the device for multiple sheet detection, the controllable drive of the suction device can be temporarily stopped by the machine control in order to hold the double sheet in a waiting position. As soon as the preceding sheet has been transported away, the former double sheet can be transferred from its waiting position to the transport device so that it is fed to the printing machine as part of an uninterrupted sheet flow. In other words: Only the double sheet and not the whole machine is stopped, the double sheet then inserted into the sheet stream.

Alternatively, it can be provided that upon detection of a multiple sheet by the device for multiple sheet detection, the suction device is driven by the controllable drive briefly against its direction to temporarily transport the detected double sheet against the sheet transport direction. As soon as the preceding sheet has reached the intended distance from the former double sheet, the suction device is again regularly driven in the running direction and the former double sheet is fed to the printing machine as part of a continuous, uninterrupted sheet flow.

Alternatively, the speed of the double arch can be reduced by reducing the transport speed of the suction device. The speed is returned to its base value once the double arch has reached its intended distance from the previous arc.

In all the alternatives described, the suction device continues to act on the former double sheet, so that only another, bow can be deducted from the sheet pile when the former double sheet was handed over to the transport device. According to the control rule of the drive of the suction device stored in the machine control, the drive pause or the direction reversal or the speed reduction is calculated by the machine control inter alia taking into account the sheet length, the desired sheet spacing and the machine speed of the printing machine. An advantage of the speed reduction and to a limited extent on the drive break is that on the one hand, the forces are kept low on the sheet, as the sheet is not pushed and on the other hand, the required speed profile is easier to implement.

In an advantageous development of the investor according to the invention, the suction device is designed such that it either has a suction element which is arranged substantially in the middle of the sheet width and / or two suction elements arranged essentially in the vicinity of a respective sheet side edge. The suction elements may in particular be suction wheels, suction rolls, suction rolls or suction belts, which are acted on by a suction air. Such suction elements and their execution are well known to those skilled in the art.

In an advantageous development of the investor according to the invention arc of the suction device with a Unterschuppung, ie a sublap, can be transferred to the transport device, so that the investor of the printing machine feeds a shingled stream of sheets. Such an investor can be carried out as in the DE 10 2008 048 287 A1 on whose paragraphs [0032] to [0035] and [0037] in conjunction with their FIGS. 4a to c is hereby incorporated by reference in full. The device for multiple sheet detection can advantageously have at least two sensors displaceable in or against the sheet transport direction and arranged one behind the other in the sheet transport direction, which enable the control of a shingling and its degree of shallow penetration. As an alternative to two individual sensors, one sensor line can also be used. Control rules can be stored in the machine control as to how the drive of the suction device is to be controlled, in order to adapt the detected actual descaling to the desired setpoint descaling.

The invention also provides methods for controlling an investor of a printing machine to guarantee a continuous sheet flow. The investor may in particular, as described above, be executed.

If sheets are to be fed to a printing machine at a distance, the method is as follows: in a first step, an uppermost sheet is withdrawn from a stack of sheets by a suction device. The so-isolated sheet is subsequently transferred to a transport device. In the transfer area, and as long as the sheet is still held by the suction device, then carried out the implementation of a multiple sheet control. In the event that a multiple arc is detected, the suction device is briefly stopped or there is a brief reversal of the direction of the suction device. As soon as the preceding sheet has been transferred to the transport device and has the intended distance from the former multiple arc held by the suction device, the former multiple sheet is likewise transferred to the transport device. If no multiple sheet is detected, then immediately followed by a deduction of a next, uppermost sheet of a sheet stack through the suction device.

If a submerged sheet stream to be supplied to a printing machine, the method is as follows: in a first step, a sheet is withdrawn from a stack of sheets by a suction device to be subsequently transferred in unterschuppter manner to a transport device. In the transfer region and as long as the sheet is still held by the suction device, a control of the descaling, i. the length of the shingles, also known as the degree of shallow, is measured. Upon detection of a deviation of the actual subsaturation from the desired subsaturation of the drive of the suction device is briefly stopped, briefly accelerated or decelerated or there is a momentary reversal of direction of the suction, so as to correct the Unterschuppung. The decision on the control of the suction device is made in response to the measurement result and can be carried out in particular in a machine control. If the actual subsidence coincides with the nominal oversupply, then the suction device continues to be operated unchanged.

The described invention and the described advantageous developments of the invention are also in any combination with each other advantageous developments of the invention.

With regard to further advantages and advantageous embodiments of the invention, reference is made to the dependent claims and the description of an embodiment with reference to the accompanying drawings.

embodiment

Fig. 1:

eine Übersichtsdarstellung einer drucktechnischen Maschine mit dem erfindungsgemäßen Anleger

Fig. 2a:

eine Momentaufnahme, zu der ein Doppelbogen erkannt wird

Fig. 2b:

eine Momentaufnahme, zu der ein Doppelbogen aufgelöst wird

Fig. 2c:

eine Momentaufnahme, zu der der ehemalige Doppelbogen übergeben wird

Fig. 3:

eine alternative Ansteuerung der Saugeinheit

Fig. 4:

die Kontrolle des Unterschuppungsgrades eines unterschuppten Bogenstroms

Fig. 5:

eine Draufsicht auf einen erfindungsgemäßen Anleger

The invention will be explained in more detail with reference to an embodiment. It show in a schematic representation

Fig. 1:

an overview of a printing machine with the feeder according to the invention

Fig. 2a:

a snapshot for which a double sheet is detected

Fig. 2b:

a snapshot to which a double sheet is resolved

Fig. 2c:

a snapshot to which the former double sheet is handed over

3:

an alternative control of the suction unit

4:

the control of the degree of desquamation of a submerged arc current

Fig. 5:

a plan view of a feeder according to the invention

In Fig. 1 is shown as a printing machine 100 a folding machine. This is composed of a feeder 1 according to the invention, a folding station 2, and a boom 3. On a sheet stack 4 stacked sheets 5.1, 5.2, 5.3 are separated by the feeder 1 and fed in a sheet flow of the folding station 2. There, the sheet 5.1, 5.2, 5.3 are folded and the folded signatures 6 below designed in the boom 3. The feeder 1 has a suction device with a suction wheel 10, which is driven by a motor 13, for example, as a motor with integrated control, servomotor, etc. The drive 13 is connected to a machine control 14. From an air unit 16, a suction air is provided to the suction wheel. Also, the air unit 16, a blown air for trailing edge blower 15 (see Fig. 5 ) provide. Between the sheet stack 4 and the folding station 2, a transport device 11 is provided with conveyor belt, also referred to as a feed table. The transport device 11 may have at least one conveyor belt such as belts or suction belt. The drive of the transport device 11 is independent of the drive 13 of the suction element 10. The area between the suction element 10 and the transport device 11 is referred to here as a transfer area. In this area is a device for multiple sheet detection 17 is provided, which has at least one sensor 12, and which is also connected to the machine control 14.

Based on FIGS. 2a to c the operation of the investor 1 according to the invention will be described in more detail. If not only a sheet 5.1, but also another sheet, a so-called double sheet 5.2 sucked and separated from the sheet stack 4 and subtracted from the suction element 10, the presence of a double sheet by the sensor 12 of the device for multiple sheet recognition 17, as in Fig. 2a represented, detected. The presence of a double sheet 5.1, 5.2 is reported to the machine control 14, which sends a control command to the motor 13 of the suction element 10. As in Fig. 2b shown, the suction wheel 10 is stopped until the sheets 5.1 and 5.2 are separated from each other. During this time, the sheet 5.2 is held in its position by the suction air of the suction element 10, and the sheet 5.1 is already transported further from the transport direction 11. Then, when the distance between the preceding sheet 5.1 and the former double sheet 5.2 corresponds to the intended value, the suction wheel 10 is driven by the motor 13 again, so that the sheet 5.2 can be transferred to the transport device 11. The sheets 5.1 and 5.2 are then fed by the transport device 11 of the folding station 2 at the intended distance and the former presence of a double sheet has no effect on the sheet flow.

In an alternative embodiment, it may be provided that a double sheet 5.2 is transported back against the sheet transport direction B by a small distance. For this purpose, a control of the motor 13 of the suction wheel 10 is such that the motor 13 is briefly driven counter to its regular direction of rotation, so that the direction of the suction wheel 10 is reversed. This procedure is in Fig. 3 indicated and it is apparent that can be achieved in an advantageous manner so that the double sheet 5.2 is not simultaneously in the range of action of the suction element 10 and the transport device 11 (see. Fig. 2b ). The sheet 5.2 is transported so far back from the suction element 10 against the sheet transport direction B, that its sheet leading edge is upstream of the trailing edge of the transport device 11. In this position, the sheet can be held short 5.2, including the motor 13th is temporarily stopped. Once the sheets have 5.1 and 5.2 the intended distance from each other, the suction member 10 is driven by the motor 13 again.

In Fig. 4 the mode of action of the feeder 1 is shown when the folding station 2 is supplied with a submerged arc stream. The sheets 5.1, 5.2, 5.3 are also separated from the suction element 10 from the sheet stack 4, the transfer device 11, however, handed over unequally with a Unterschuppung. The Unterschuppung between the first sheet 5.1 and the second sheet 5.2 corresponds to the target subshadling U_Soll, while the Unterschuppung the second sheet 5.2 and the third sheet 5.3 an actual Unterschuppung U_Ist corresponds, which is greater than the desired Unterschuppung U_Soll. In order to determine this deviation of the degree of subsquading, the device for multiple sheet recognition 17 is equipped with at least two sensors, which are displaceable in or against the sheet transport direction B and are arranged one behind the other in the sheet transport direction B. The sensors 12 are thus adjustable in their distance to the desired Unterschuppung U_Soll. Corresponds to the measured Unterschuppung U_Ist not the stored in the machine control 14 target Unterschuppung U_Soll, so a control pulse to the controllable drive 13 of the suction element 10 is triggered by the machine control. This causes the drive speed of the Saugelements 10 is changed briefly, so as to correct the Unterschuppungsgrad the arc 5.2 and 5.3. In the illustrated example of a too large actual subsolation U_Ist, the suction element 10 can either be stopped for a short time or rotated slowly for a short time or briefly driven counter to its usual direction of rotation. As a result, the sheet 5.3 is stopped for a short time, or moved counter to the sheet transport direction B, wherein the actual Unterschuppung U_Ist is reduced until it corresponds to the target Unterschuppung U_Soll.

The transport speed of the transport device 11 can be adjusted in accordance with a rule stored in the machine control 14, eg, a slight speed reduction depending on grammage, sheet surface, sheet format, machine speed, etc. can be determined.

Fig. 5 shows a plan view of the feeder 1: from a sheet stack 4 arc 5.2, 5.1 separated by suction elements 10 of a suction device and withdrawn. To assist the singulation process, trailing edge blowers 15 may be provided at the trailing edge of the sheet pile 4. The suction elements 10 are in the embodiment of Fig. 5 designed as suction wheels. In each case, a suction wheel is arranged in the region of the side edge of the sheet 5.2. In order to enable a format adaptation of the position of the suction elements 10, a displaceability b of the suction elements 10 is provided. Instead of the two located in the side edge region of the sheet 5.2 suction elements 10 can also - as dash-dotted lines indicated - a centrally arranged to the sheet width of the sheet 5.2 suction element 10 may be provided. The device for double sheet recognition 17 is - as seen in the sheet transport direction B - arranged between the suction elements 10 and the conveyor belts of the transport device 11.

If the dissolution of the multiple sheets is not successful, it can be ensured by rejecting that no multiple sheet enters the processing stations of the printing machine 100.

For this purpose, the feeder 1 can additionally be equipped with a device (not shown) for discharging multiple sheets in a transport direction-disconforming discharge direction (eg upwards or backwards), as described, for example, in US Pat DE 103 28 803 A1 or the JP 5901029 A is described. Also, a discharge of multiple sheet could be accomplished to the rear top in a Ausschleuskassette not shown by means of existing in the feeder 1 suction elements 10.

As in the Figures 6a and 6b shown, in the region of the feed table 11 additional suction elements 10.1. be provided. This makes it possible to use the transport path in the region of the feed table 11 for the resolution of multiple sheets 5.1, 5.2 or for the correction of the Unterschuppung U. Thus, for example, an upper sheet could be held by an additional suction element 10.1 located above the sheet transport plane, while a lower sheet is transported away by the suction belt below the sheet transport plane.

For the additional suction elements 10.1. are different bays in the region of the feed table 11 conceivable. Also, the additional suction elements 10.1 can be activated individually.

LIST OF REFERENCE NUMBERS

1

investor

2

folding station

3

boom

4

sheet pile

5.1

1st bow

5.2

2nd bow

5.3

3rd bow

6

signature

10

Suction elements (suction wheel)

10.1

additional suction element

11

Transport device (feed table)

12

Sensor of the device for multiple sheet recognition

13

Controllable drive (motor)

14

machine control

15

Trailing edge blowers

16

air unit

17

Device for multiple sheet detection

100

printing machine

a

Displacement of the sensors

b

Displaceability of the suction elements

B

Sheet transport direction

U

Unterschuppung

U_IST

ACTUAL Unterschuppung

U_Soll

Target Unterschuppung

Claims (10)

Feeder (1) for a printing machine (100) with a machine control (14), with a suction device (10) for withdrawing a sheet (5.1, 5.2, 5.3) from a sheet stack (4), a transport device (11) for further transport of Sheet (5.1, 5.2, 5.3) in the sheet transport direction (B) and a substantially between suction device (10) and transport means (11) arranged means for multiple sheet detection (17),
characterized,
in that the suction device (10, 10.1) has a controllable drive (13), that the device for multiple sheet recognition (17) and the controllable drive (13) are connected to the machine control (14) by signal technology and the controllable drive (13) as a function of Measurement result of the device for multiple sheet recognition (17) is driven,
wherein in the machine control (14) control rules for the drive (13) of the suction device (10, 10.1) are deposited. An investor according to any one of the preceding claims,
characterized,
that at multiple sheet detection of the device for multiple sheet detection (17) is briefly be stopped, the controllable drive (13) of the suction device (10, 10.1) by the machine control (14), for sucking sustaining an arc (5.1, 5.2, 5.3) in a waiting position. An investor according to any one of the preceding claims,
characterized,
that at multiple sheet detection of the device for multiple sheet detection (17) of the suction device (10, 10.1) from the controllable drive (13) is briefly driven at a reduced speed, for transporting a sheet (5.1, 5.2, 5.3) at a reduced speed in the sheet transport direction (B) , An investor according to any one of the preceding claims,
characterized,
that at multiple sheet detection of the device for multiple sheet detection (17) of the suction device (10, 10.1) from the controllable drive (13) is briefly counter to its running direction can be driven, for transporting a sheet (5.1, 5.2, 5.3) counter to the sheet transport direction (B). An investor according to any one of the preceding claims,
characterized,
that the suction device has a substantially centrally arranged to the sheet width of the suction element (10) or two substantially arranged in the vicinity of a respective sheet side edge suction elements (10). Feeder according to claim 5,
characterized,
that the suction elements (10, 10.1) as the suction wheels, suction rolls or suction belts are constructed. An investor according to any one of the preceding claims,
characterized,
that from the suction device (10, 10.1) sheet (5.1, 5.2, 5.3) with a Unterschuppung (U_SOLL, U_IST) to the transport device (11) can be transferred, so that the feeder (1) of the printing machine (100) a shingled stream of sheets (5.1, 5.2, 5.3). Feeder according to claim 7,
characterized,
in that the device for multiple sheet recognition (17) has at least two sensors (12) displaceable in the sheet transport direction (B) and arranged in succession in the sheet transport direction (B) for checking a subsquading (U_IST). Method for operating an investor (1) of a printing machine (100), in particular according to one of claims 1 to 6, with the following steps: a) removal of sheets (5.1, 5.2, 5.3) from a stack of sheets (4) by a suction device (10) b) transfer of sheets (5.1, 5.2, 5.3) to a transport device (11) c) performing a multiple sheet control in the transfer area d) Upon detection of a multiple sheet short-term stopping or momentary reversal of direction of the suction device (10, 10.1) for the resolution of the multiple sheet without stopping the printing machine e) transfer of the sheet detected as a multiple sheet to the transport device (11) Method for operating an investor of a printing machine, in particular according to claims 7 or 8, with the following steps: a) removal of sheets (5.1, 5.2, 5.3) from a stack of sheets (4) by a suction device (10) b) transfer of submerged sheets (5.1, 5.2, 5.3) to a transport device (11) c) performing a control of the descaling in the transfer area d) Upon detection of a deviation of the actual descaling (U_IST) from the desired descaling (U_SOLL) brief stop, momentary acceleration or deceleration or short-term reversal of direction of the suction device (10, 10.1) to correct the Unterschuppung (U_IST) without stopping the printing machine ,

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