JP4960552B2 - Method for aligning a sheet-like material at a reference edge - Google Patents

Abstract

The invention relates to a process for alignment of sheet material (1) which is processed in a machine which processes sheet material (1). To do this the sheet material (1) is aligned into one conveyor plane (9) laterally and with respect to its twisting (6) with reference to its conveyor direction (22). The position of the sheet material (1) in the conveyor plane (9) is always acquired at a point (35) on one side edge (24) of the sheet material with a position which is defined to the reference edge (23) of the sheet material (1).

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for aligning a sheet-like material at a reference edge before the sheet-like material is further processed in a machine for processing the sheet-like material.
[0002]
[Prior art]
A sheet aligning device is known from German Offenlegungsschrift 4,416,564. The apparatus for aligning moving sheets along a substantially flat transport track moves in a number of orthogonal directions, for example in a direction transverse to the transport track and to avoid a tilting posture as viewed in the transport track direction. The sheets to be aligned can be performed. The sheet aligning device includes a first roller device including a first pressure roller that is rotatably supported around an axis, and the axis is in a plane extending parallel to the plane of the conveyance track. And extends substantially perpendicular to the sheet conveying direction along the conveying track. The second roller device includes a second pressure roller that is rotatably supported about an axis, and the axis is located in a plane extending in parallel to the plane of the transport track and is on the transport track. Along the sheet conveying direction. Furthermore, a third roller device having a third pressure roller supported rotatably around an axis is provided, and the axis is located in a plane extending parallel to the plane of the transport track. Further, it extends substantially perpendicular to the sheet conveying direction along the conveying track. A third roller device that is rotatable about an axis located in a plane extending parallel to the plane of the transport track and extending substantially perpendicular to the sheet transport direction along the transport track is provided as the roller device. It is possible to move in a direction extending laterally with respect to the transport track along the rotation axis. Further, a control device is provided, and the control device is configured to align the leading edge of the sheet moving in the sheet transport direction along the transport track at a position arranged perpendicular to the sheet transport direction. Alternatively, it is operatively coupled to the second or third roller device and selectively controls the rotation of the first and second roller devices. Further, the control device performs rotation and lateral movement of the third roller device in order to align the moving sheet in a direction extending laterally with respect to the sheet conveyance direction and in a direction in which the sheet is moved along the conveyance path. Control.
[0003]
However, the alignment device known from German Offenlegungsschrift 4,416,564 can only meet the required alignment accuracy to a limited extent. In order to obtain the required alignment accuracy of the sheet-like material, known sheet alignment devices require extensive modifications which are economically inconvenient.
[0004]
In a printing machine that processes sheets that function on the offset principle, the sheets are before being aligned with side marks and pull-type lay marks provided in the plane of the paper feed tray. In addition, the sheet is conveyed to the sheet feeding table in an offset arrangement. After alignment of the sheet-like material, the sheet-like material is delivered to the pre-gripper in an aligned state, the pre-gripper being accelerated to the machine speed and positioned downstream of the pre-gripper. Deliver to the cylinder that guides the sheet. Another alignment concept uses a cylindrical roller, and the roller core of the roller is coated with a rubber coating. When the sheet-like material is aligned during material feeding by changing the speed between the left and right rollers acting on the sheet-like material with such a device, the sheet-like material is Rotate around the rotation point. The rotation point is provided on a stationary roller or occupies the outside of the low rotation number roller during the feeding of the sheet-like material or is located between the two rollers.
[0005]
If the detection of the side edge of the sheet is performed by a simple photoelectric barrier, a legitimate measurement of the edge position of the sheet-like material cannot be obtained. The photoelectric barrier provides only binary information about the deviation of the sheet-like material as to whether it is significantly left or right, and then for lateral (left-right) alignment, the sheet-like material is Sent until switched. The time required for lateral alignment of the sheet-like material is related to the initial value of the lateral (left and right) registration error. When lateral alignment is performed during the movement of the sheet-like material in the transport direction, the point in time when the photoelectric barrier is switched in the sheet transport direction is variable. If the left / right study error is small, the alignment is as good as the difference, and the spacing between the leading edge of the sheet and the switching point at the side edge of the sheet is slightly smaller than would occur with a large left / right registration error. . Therefore, in the case of the alignment concept, the cutting error of the sheet-like material, that is, the right angle between the leading edge and the side edge is involved in the alignment. Further, in brochure printing for printing A3 / plate, alignment is performed with respect to the leading edge and side edge, and then folded into A4 and bound, and the image extends over two sides of various sheets. In the case of extension, the problem arises that the register accuracy at the folding back can only be obtained within the range of the cutting error, which is often regarded as inappropriate.
[0006]
[Problems to be solved by the invention]
It is an object of the present invention to maintain the alignment accuracy of a sheet-like material during feeding of the sheet-like material in the conveying direction regardless of the processing error of the sheet-like material to be image printed. There is.
[0007]
[Means for Solving the Problems]
The object according to the invention is a method for aligning a sheet-like material, wherein the sheet-like material is processed in a machine for processing the sheet-like material and for this purpose a conveying plane. In the type in which the sheet-like material is aligned laterally and with respect to torsion in relation to the conveyance direction of the sheet-like material, the position of the sheet-like material in the conveyance plane is always determined in each printed book. This problem is solved by detecting the position of the side edge of the sheet and the position of the point is defined with respect to the reference edge of the sheet-like material.
[0008]
【Effect of the invention】
The advantage obtained by the method according to the invention is in particular that the position of the sheet-like material is always measured at the same position relative to the reference edge in each copy of the sheet-like material and then the sheet. It is that a controlled correction of the position is made. As a result, the image position in the sheet-like material is always uniquely defined with respect to the reference edge, for example, the leading edge of the sheet and the reference point of the side edge of the sheet-like material. Thereby, when post-processing the sheet-like material, the registration accuracy is no longer limited by the cutting error of the sheet-like material, for example during manufacture and folding.
[0009]
According to another advantageous method according to the invention, a line sensor can advantageously be used to detect the position of the sheet-like material in the transport plane. The line sensor can advantageously be configured as a CCD line or a diode line. The use of a line sensor allows detection of a number of commonly used sheets of sheet-like material at their lateral position, and the use of a line sensor provides accurate detection of the lateral position of the sheet-like material. High resolution accuracy can be obtained.
[0010]
By means of the method according to the invention, the sheet-like material can be subsequently conveyed in the conveying direction, in particular during its alignment. This ensures that the feeding speed of the sheet-like material to the processing machine arranged downstream is not limited by the alignment and alignment speed.
[0011]
In the method according to the invention, the alignment accuracy is independent of the processing errors of the sheet-like material, which may be paper, cardboard or thin board, for example cutting errors. This is because the position of the sheet-like material is detected at the same location consisting of a defined position relative to the reference edge of the sheet-like material and a reference point at the edge.
[0012]
For the always same detection of the position of the sheet-like material in the transport plane, the print image position in the sheet-like material is always defined via a reference interval. The first reference interval is formed by the interval of the printed image from the reference edge of the sheet-like material. Advantageously, the leading edge of the sheet is selected as the reference edge of the sheet-like material. The second reference interval that defines the position of the printed image relative to the sheet-like material is a slight distance from the leading edge in the horizontal direction when viewed in the reference point, for example, the sheet-like material conveyance direction. This is the distance between the reference point of the side edge of the sheet-like material positioned and the printed image.
[0013]
In an advantageous use case, the method according to the invention is realized in order to improve the alignment accuracy in an alignment unit arranged upstream of the printing unit of a digitally operated rotary printing press. In this case, the printing material to be processed, for example thin sheets, cardboard or paper, is aligned before the printing material is processed on a printing or possibly digitally working machine.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As can be seen from FIG. 1, a sheet-like material oriented at right angles to the feed direction 22, for example a printed sheet 1, is printed on its surface surrounded by a frame-like edge 3. Print image 2. The deviation Δx or Δy marked in the printing surface 2 and the frame 3 indicating the position error in the x direction and the y direction occurs when the printed image 2 is printed on the surface of the sheet-like material 1. The deviations indicated by reference numerals 4 and 5 are positional deviations, on the other hand, according to FIG. 2, the angular deviation of the printed image 2 is related to the position of the sheet-like material on the printed sheet. It is shown in the figure.
[0015]
As is apparent from FIG. 2, the generated angular error Δφ is indicated by reference numeral 6. The printed image 2 is printed on the surface of the printing material 1 at the illustrated position. In this case, the printing material is conveyed with the leading edge 23 first as viewed in the conveying direction 22.
[0016]
According to FIG. 3, a turning register is schematically shown, in which case an offset (shift) occurs between the printed images 2 on the front and back sides of the sheet-like material 1 each time. ) 7 is shown. According to FIG. 3, the offset is indicated by 7 or Δx or Δy. Turning registration is particularly important for translucent paper types as well as brochure printing.
[0017]
From the schematic side view of FIG. 4, the sheet alignment interface and transport to the conveyor belt are shown. An alignment unit 8 is disposed on the upstream side of the conveying belt 10 that circulates around the feed roller 11 or the control roller 12, and the sheet-like material 1 is received by the conveying plane 9 on the surface of the conveying belt. After passing through the alignment unit 8 described in detail below, the aligned sheet-like material 1 reaches the conveying plane 9 on the surface of the conveying belt 10. After passing the feed roller 11, the sheet-like material 1 is loaded by adjusting flaps or adjusting lips that are movable in the adjusting direction 13. The adjustment flap or adjustment lip is a plastic component which can be moved from the close-adjusted position 13.1 to the remote-adjusted position 13.2. This is indicated schematically by a solid or broken line. Using the adjustment flap or the adjustment lip, the sheet-like material 1 is pressed against the surface of the conveyor belt 10 in the aligned state of the sheet-like material 1. After passing through the crimping member, the sheet brought to the surface of the conveyor belt passes through the charging unit 14. In the charging unit, an electrode 15 is received inside a hood-like cover, and this electrode is used for the static charge of the sheet-like material 1 and thus for the attachment of the sheet-like material on the surface of the conveying belt. Used.
[0018]
A leading edge sensor 17 is arranged downstream of the charging unit 14 which is only schematically shown in FIG. The leading edge sensor has a radiation source 18 arranged below the sheet transport plane 9 and a lens device 19 is placed in front of the radiation source. The radiation field 20 emitted from the lens device 19 passes through the transport plane 9 and collides with a diaphragm device provided above the transport plane 9 of the sheet-like material 1. The diaphragm device is followed by a receiver 21, which detects the presence or absence of the leading edge of the sheet-like material 1.
[0019]
In FIG. 7, a plan view of the alignment unit 8 is shown, and the components of the alignment unit are schematically shown. The sheet-like material 1 conveyed in the conveyance direction 22 has reached the alignment unit 8. The leading edge 23 of the sheet-like material is offset, i.e. offset, with respect to the conveying direction 22, which causes an oblique course of the side edges 24 of the sheet-like material 1. When the sheet leading edge 23 occupying the inclined position with respect to the transport direction 22 passes through the first photoelectric barrier 26, the driving devices 27, M 1, and M 2 that drive the rotating member 25 via the single shaft 32 become the feed speed. Accelerated. By means of the control of the drive device 27 (M1, M2) released via the photoelectric barrier 26, each printed copy of the sheet-like material 1 can be configured as a segment roller in an advantageous embodiment. In contact with the matching circumferential section. Differences that may occur in the feed movement due to the size and shape errors of the two rotating members 25 occur in the same manner in each print book of the sheet-like material 1 and can be easily calibrated.
[0020]
After both rotating members 25 are rotated by the passage of the first photoelectric barrier 26, the sheet-like material 1 passes through the sensor unit 30.1 disposed downstream of the first photoelectric barrier 26 at the feeding speed. Be transported. When the first sensor of both sensors of the sensor unit 30.1 detects the sheet leading edge 23 of the sheet-like material 1, the counting unit starts counting in a motor step. In this case, the counting process ends when the second sensor of the sensor unit 30.1 is switched and holds the detected difference. A correction value is formed from the count state detected in the above format, and the correction value is delivered as an additional feed to the last-started segment roller drive device 27, ie indicated by drive device 27 or M2 indicated by M1. It is delivered to the drive device 27. This accelerates the corresponding rotating member 25 configured as a segment roller to an increased feed rate until it fully compensates for the predetermined stroke difference. At the end of the correction process, the sheet leading edge 23 is oriented exactly perpendicular to the transport direction 22. After the position correction, the sheet-like material 1 is continuously transferred in the conveying direction 22 from the first pair of segment rollers 25 to another pair of segment rollers 25 arranged on the downstream side of the segment rollers. The segment rollers can be received on a common shaft 31. Now, the segment roller pair 25 driven via the driving device 27 (M1) and the driving device 27 (M2) is cut off and moved to the neutral position.
[0021]
The sheet-like material 1 corrected and aligned with respect to the angular position moves to the sensor field 30 where the position of the side edge 24 of the sheet-like material 1 is measured. A position variation for the driving device 27 (M4) is detected from the detected measurement value, and the driving shaft of the driving device extends in parallel to the conveyance direction 22 of the sheet-like material. The position of the sheet-like material 1 is corrected parallel to the moving direction 22 of the sheet-like material by the drive device 27 received in the second directing means 29 (see FIG. 7). .
[0022]
The sheet-like material 1 with the angular position and the lateral position aligned in this manner is placed under the adjusting member in the form of an adjusting flap or adjusting lip installed at position 13.1 or 13.2. It moves towards the conveyor belt 10 and thereby enters a printing unit arranged downstream at a precisely aligned position. FIG. 6 shows a variant embodiment of the rotating member 25 received in the alignment unit 8 and located above the transport plane 9, which in an advantageous embodiment is characterized by an interruption. It can be configured as a segment roller having a circumferential surface 33 attached thereto. The segment roller 25 rotates in the direction 34 shown by the arrow and draws approximately 3/4 · circle with respect to the rotation axis. Below each segment roller 25, a roller for supporting the sheet-like material 1 is shown. The support roller can be constructed in one piece or it can comprise a roller core and a coating held on it. The rotating member configured as the segment roller 25 is illustrated in the left part of FIG. 6 in the neutral position, whereas the rotary member conveyed in the conveying direction 22 of the sheet-like material 1 in the right part of FIG. The book is gripped by the peripheral surface 33 and conveyed in the conveying direction 22 corresponding to the rotation direction 34. FIG. 7 illustrates the correction of the angular position of the sheet-like material 1 when passing through the alignment unit 8. In the position illustrated in FIG. 7 of the sheet-like material 1, the leading edge 23 of the sheet-like material has just reached the last sensor of the sensor pair 30.1 and is therefore indicated by M1 of the segment roller 25. The driving device 27 is activated to compensate the angular position of the sheet-like material 1 in relation to the transport direction of the sheet-like material. Furthermore, unlike the drive devices M3 and M4 which are coupled to each other via a consistent drive shaft 31, the segment rollers 25 which are coupled to the drive devices M1 and M2 are each driven via a single shaft. After correcting the angular position of the sheet-like material 1 by different rapid control of the respective drive devices 27 (M3, M4) of the segment roller 25, the sheet-like material 1 is corrected in its lateral position. . After measuring the position of the side edge of the sheet-like material 1 by means of the sensor 31, the sheet-like material 1 is accurately aligned parallel to the transport direction 22 and in this case the sheet via the drive M4. The sheet-like material 1 is displaced in the conveying plane 9 before reaching the adjusting member 13 and before the sheet-like material rides on the surface of the conveying belt 10. The feeding device 27 (M1), which is oriented in the first direction control means 28, ensures the feeding of the sheet-like material 1 with the leading edge 23 correctly aligned via the common shaft 31. On the other hand, the sheet-like material 1 is aligned in the lateral position via a drive device 27 (shown as M4) received in the second direction control means 29.
[0023]
FIG. 8 shows the effect of lateral alignment due to errors, for example the cutting error of the sheet-like material 1 to be processed.
[0024]
In FIG. 8, two printed books of the sheet-like material 1 are shown superimposed. Each printed book of the sheet-like material 1 has a longitudinal length 43 and a width 42 as viewed in the transport direction 22. Each printed book of the sheet-like material 1 is conveyed in the conveying direction 22 in advance of the leading edge 23. In this case, a side edge 24 extending substantially in parallel is connected to the leading edge 23. The mutual offset 39 in the printed sheet of sheet-like material shown in FIG. 8 causes the side alignment members to be activated at different times based on the different switching points 40 or 41 that occur. The two switching points 40 or 41 for the printing book illustrated by superimposing the sheet-like material 1 cause different lateral alignment accuracy in relation to the left / right registration error 39 that occurs each time, and the left / right registration error. Cause alignment results that vary significantly depending on the printing material and lead to defects. In the alignment process, the cutting error or left-right registration error 39 of the sheet-like material 1, that is, the right angle between the sheet front edge 23 and the side edge 24 connected thereto is included in the alignment result. . For example, in a brochure print that prints the sheet-like material 1 of the plate A3, it is aligned with respect to the leading edge 23 and the side edge 24, then folded and bound into A4, and the two printed images 37 are two different sheets. When extending over both sides of the paper, there arises a problem that registration accuracy can be obtained at the folding back only within the cutting error range. First, as the cutting error 39 in the sheet-like material 1 is larger, for example, the registration accuracy at the folding back at the time of brochure printing becomes inaccurate.
[0025]
According to FIG. 9, the different switching points 40 or 41 generated due to errors in the sheet-like material 1 for the alignment member 25 are always based on the position of the sheet-like material 1 in the transport plane 9. By being measured at the same position relative to the edge 23, it is eliminated. This is done, for example, by means of sensor elements embedded in the transport plane 9, preferably configured as line sensors, for example as CCD lines and as diode lines. A line sensor with appropriate resolution allows a controlled correction of the position of the sheet-like material 1 in the transport direction 22 after recording the sheet position relative to the reference edge 23. . The position 37 of the printed image present in the sheet-like material 1 is defined by a spacing 36 relative to the reference edge 23, whereas the reference edge is spaced relative to the measuring point 35 at the side edge. 38. As a result, when the sheet-like material 1 is post-processed, the registration accuracy is no longer limited by the cutting error of the sheet-like material 1, so the registration inaccuracy at the time of brochure printing is two different sheets of paper. It no longer occurs in an image extending over two pages.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positional deviation of a printed image that is printed relative to the surface of a printing material that holds the printed image.
FIG. 2 is a diagram showing an offset of a print image caused by a rotation offset in a sheet-like material.
FIG. 3 is a diagram illustrating an offset of a print image printed on a lower surface side and an upper surface side of a sheet-like material by duplex printing.
FIG. 4 is a schematic side view of a sheet feeding area of a machine for processing a sheet.
FIG. 5 is a plan view of a driving device, a detection mechanism, and an alignment member for a rotating element that align sheets relative to the sheet moving direction.
FIG. 6 is a view showing a rotation member for alignment formed on the upper side of a conveyance plane of a sheet-like material as a segment roller.
FIG. 7 is a diagram showing alignment of a sheet-like material provided with a segment roller driving device for alignment.
FIG. 8 is a diagram illustrating an influence on lateral alignment due to an error of a printing material.
FIG. 9 is a diagram illustrating the definition of reference points and reference edges in a sheet-like material.
[Explanation of symbols]
1 sheet material, 2 printed image, 3 frame, 4 position error X / direction, 5 position error Y / direction, twist error, 7 front and back surface offset, 8 alignment unit, 9 transport plane, 10 transport belt, DESCRIPTION OF SYMBOLS 11 Feed roller, 12 Control roller, 13 Adjustment member, 13.1 1st position, 13.2 2nd position, 14 Charging unit, 15 Electrode, 16 Support means, 17 Leading edge sensor, 18 Radiation source, 19 Lens device, 20 radiation field, 21 receiver, 22 transport direction, 23 front edge, (reference edge), 24 side edge, 25 segment roller, 26 photoelectric barrier, 27 drive device, segment roller, 28 first direction control drive Device, 30 line sensor, 30.1 sensor pair, 31 common shaft, 32 single shaft, 33 segment roller circumferential surface, 34 rotation direction 35 reference point edge, 36 reference interval x, the printed image position, 38 reference interval y, error, 40 switching point, 41 switching point 42 width, 43 longitudinal extending

Claims (8)

Method for aligning a sheet-like material (1), wherein the sheet-like material is processed in a machine for processing the sheet-like material and for this purpose in one transport plane (9) in relation to the conveying direction of the sheet paper-like material (22) in shall be aligned relates moreover twisted at laterally, the position of the sheet-like material in the conveyance plane (9) (1), the line sensor (30) It was used to detect a predetermined point of the side edge (24) of each book block always sheet-like material (1) (35), the position of the predetermined point (35) of sheet-like material ( It is those which are defined relative to a reference edge (23) of 1), the sheet-like material (1) variable in to process the plate type and the sheet-like material cutting error of the (39) Do not affect the image position (37) by always measuring the position of the sheet-like material (1) at the same predetermined point (35). The printed image position (37) relative to the position of the sheet-like material (1) via the reference spacing (36, 38) relative to the reference edge (23) and the predetermined point (35). A method for aligning sheet-like materials relative to each other. 2. The method according to claim 1, wherein a CCD line sensor (30) is used to define the position of the sheet-like material (1). 2. A method according to claim 1 , wherein diode lines are used to define the position of the sheet-like material (1).   2. The method according to claim 1, wherein the sheet-like material (1) is subsequently transported in the transport direction (22) during alignment. A first reference distance, sheet formed by the spacing between the leading edge (23) and print image position (37) of the leaf paper-like material (1), The method of claim 1, wherein. The method according to claim 1 , wherein the second reference interval is formed by the interval between the reference point (35) of the side edge (24) of the sheet-like material (1) and the print image position (37). In a method for aligning a sheet-like material (1) in a conveying plane (9) while the sheet-like material (1) moves in a conveying direction (22) in a printing press,
a) using a sensor to detect the leading edge (23) of the sheet-like material (1),
b) using the first line sensor (30) to measure the position of the reference edge (24) of the sheet-like material (1) in the direction transverse to the conveying direction (22), Measuring the position (35) at a reference interval (36) from the detected leading edge (23);
c) until the reference edge (24) measured by the first line sensor (30) reaches the selected lateral position (38) at the reference interval (36) from the detected leading edge (23), Aligning the sheet-like material (1) laterally using a motor (27);
A method for aligning a sheet-like material (1), characterized in that d) rotate the sheet about the transport direction (22),
e) using the second line sensor (30) opposite the first line sensor (30) to measure the position of the reference edge (24) of the sheet-like material (1);
f) until the reference edge (24) measured by the second line sensor (30) reaches the selected lateral position (38) at the reference interval (36) from the detected leading edge (23), 8. The method according to claim 7, wherein the sheet-like material (1) is aligned laterally using a motor (M4).

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