Method for operating printing press

Abstract

The operation method of the printing machine comprises a longitudinal format mode and a transverse format mode. In both modes, the pages are both printed on the front side and on the back side, and are turned between them in a turning device (7). Furthermore, in both modes, the orientation of one sheet edge of the respective sheet relative to the other sheet edge is determined by means of at least one detection device (8), and on the basis thereof, sheet alignment is carried out for reverse printing, said alignment being carried out in an alignment device (5). The front and back printing is carried out in the printing station (3), preferably by inkjet.

Description

Technical Field

[0001] This invention relates to a method for operating a printing press in different modes. Background Technology

[0002] This type of method is used to variably print on pages between printing jobs.

[0003] For example, US 8,308,158B2 describes a method for operating a printing press, wherein printing is performed on one side of a first page in a first mode "single-sided printing" and on both sides of a second page in a second mode "double-sided printing". The document also states that the invention described herein is applicable whether the page is transported with its long side as the leading edge or with its short side as the leading edge.

[0004] EP2,064,140B1 describes a page alignment device in a printing press, constituting another prior art. Summary of the Invention

[0005] The objective of this invention is to provide an alternative method for operating a printing press.

[0006] This task is solved by a method of operating a printing press in different modes, characterized in that, in a first mode, a first sheet is conveyed in a longitudinal format along a conveying plane in the conveying direction, front printing is performed on the front side of the first sheet, the first sheet is flipped in a flipping device, and reverse printing is performed on the back side of the first sheet, wherein between the flipping and reverse printing, the first sheet is aligned by means of a first roller pair and a second roller pair, wherein between front printing and alignment, the position of the first sheet edge relative to the second sheet edge is determined by means of a reflective light scanner of a detection device, and the first sheet edge and the second sheet edge... The edges extend laterally relative to the conveying direction; in the second mode, the second sheet is conveyed in a lateral format along the conveying plane in the conveying direction, front printing is performed on the front side of the second sheet, the second sheet is flipped in a flipping device, and reverse printing is performed on the back side of the second sheet, wherein between flipping and reverse printing, the second sheet is aligned by means of a first roller pair and a second roller pair, wherein between front printing and alignment, the position of the first sheet edge relative to the second sheet edge is determined by means of a reflective light scanner of a detection device, and the first sheet edge and the second sheet edge extend laterally relative to the conveying direction, respectively.

[0007] One advantage of the method of the present invention is that even those pages that deviate relatively large from the ideal rectangular shape within their manufacturing tolerances can be aligned in this way, thereby avoiding damage to subsequent processing of these pages after printing, such as angular errors between the printed image and the cut image.

[0008] The following extensions can be implemented individually or in any combination: When aligning the first page based on the orientation of the first page edge relative to the second page edge, the first motor and the second motor can be controlled by a control device, and the first motor can drive the first roller pair, and the second motor can drive the second roller pair.

[0009] Between the front printing on the front of the first page and the alignment of the first page, the other orientation of the edge of the first page relative to the edge of the second page can be determined by means of another reflective light scanner of another detection device.

[0010] The average of the orientation determination results from the first page edge relative to the second page edge using a pair of reflected light scanners can be generated by computer and the orientation determination results from the first page edge relative to the second page edge using another pair of reflected light scanners.

[0011] When aligning the first page according to the average value, the first motor and the second motor can be controlled by the control device, and the first motor can drive the first roller pair and the second motor can drive the second roller pair.

[0012] When aligning the second page based on the orientation of the first page edge relative to the second page edge, the first motor and the second motor can be controlled by a control device, and the first motor can drive the first roller pair, and the second motor can drive the second roller pair.

[0013] Between the front printing on the front of the second page and the alignment of the second page, the other orientation of the edge of the first page relative to the edge of the second page can be determined by means of another reflective light scanner of another detection device.

[0014] The average of the orientation determination results from the first page edge relative to the second page edge using a reflective light scanner and the orientation determination results from the first page edge relative to the second page edge using another reflective light scanner pair can be generated by computer.

[0015] When aligning the second page according to the average value, the first motor and the second motor can be controlled by the control device, and the first motor can drive the first roller pair and the second motor can drive the second roller pair.

[0016] The front printing on the front of the first page and the reverse printing on the back of the first page can be done by inkjet printing, and the front printing on the front of the second page and the reverse printing on the back of the second page can be done by inkjet printing.

[0017] The flipping device can be a flipping bag slot. Attached Figure Description

[0018] Further solutions can also be derived from the following description of the embodiments and accompanying drawings. The accompanying drawings are as follows.

[0019] Figure 1 A printing press is illustrated in a schematic diagram.

[0020] Figure 2a Show Figure 1 A side view of the page alignment device of a printing press, showing the first page orientation detection in a landscape format front-facing printing mode.

[0021] Figure 2b Showing with Figure 2a The corresponding top view.

[0022] Figure 3 Show Figure 2a and 2b A top view of the page alignment device in the image shows the second page orientation detection in a landscape format front-facing printing mode.

[0023] Figure 4 Show Figure 2a and 2b A top view of the page alignment device, showing page alignment in a landscape format front-facing printing mode.

[0024] Figure 5 Show Figure 1 A top view of the page alignment device of a printing press, showing page orientation detection in a portrait format front-facing printing mode.

[0025] Figure 6 Show Figure 1 A top view of the page alignment device of a printing press, showing page alignment in a portrait format front-facing printing mode.

[0026] Figure 7 Show Figure 1 A top view of the sheet measuring device of a printing press, showing the first sheet orientation detection at the leading edge of the sheet in a landscape format reverse printing mode.

[0027] Figure 8 Show Figure 7 The page measuring device in the diagram shows the second page orientation detection at the leading edge of the page in a landscape format reverse printing mode.

[0028] Figure 9 Show Figure 7 The page measuring device in the diagram shows the first page orientation detection at the rear edge of the page in a landscape format reverse printing mode.

[0029] Figure 10 Show Figure 7 The page measuring device in the diagram shows the second page orientation detection at the rear edge of the page in a landscape format reverse printing mode.

[0030] Figure 11 Show Figure 1 A top view of the page alignment device of a printing press, showing page alignment in a landscape format reverse printing mode.

[0031] Figure 12 Show Figure 1 A top view of the page alignment device of a printing press, showing page alignment in a portrait format reverse printing mode. Detailed Implementation

[0032] Figure 1 A digital printing press is shown for printing on sheets using a non-intrusive printing method (NIP), particularly inkjet printing. The press includes a sheet inlet device 1, such as a sheet feeder, and a sheet outlet device 2, such as a sheet receiver, which are schematically indicated by arrows in the figure. The press also includes a printing station 3, on which multiple print heads are arranged, and preferably one or more dryers are also arranged for drying the printed image on the sheets; these are not shown together in the figure.

[0033] The sheets travel along conveyor path 4 in the printing press, where alignment devices 5 are arranged. Alignment devices 5 properly align the sheets for subsequent printing at printing station 3. After the front side of the respective sheet is printed (front printing), the sheet can be selectively guided by switching switch 6 to sheet discharge device 2 or to flipping device 7, specifically a flipping slot. In the latter case, the sheet is flipped in flipping device 7 and then passes through printing station 3 again, where the back side of the sheet is then printed (reverse printing).

[0034] A plurality of detection devices 8 for detecting the edges of sheets are preferably arranged along the conveyor path 4. The number of detection devices 8, in terms of their rollers, is... Figure 1Simplified representation. The first detection device 8 is arranged in the section of the conveyor path 4 between the printing station 3 and the switching switch 6. The second detection device 8 is arranged in the section of the conveyor path 4 between the switching switch 6 and the tilting device 7. The third detection device 8 is arranged in the section of the conveyor path 4 between the tilting device and the alignment device 5. All three detection devices 8 or any two of them may be present. The detection devices 8 send signals to a computer 9, which belongs to or is connected to a control device 10, which drives the first motor 11 and the second motor 12 of the alignment device 5 (see...). Figure 2b The average value measured by the detection device 8 is formed in the computer 9. A lower-cost variant also exists in which only one detection device 8 is present and averaging is not performed.

[0035] exist Figure 2a and 2b The alignment device 5 is shown in more detail below. A section of the conveying path 4 forms a conveying plane 13, in which the alignment device 5 is arranged. The pages are conveyed sequentially along the conveying plane 13 in the conveying gap between guide plates 15 by means of roller pairs 16 in the conveying direction 14. Figure 2b The top view is shown, but for clarity, the upper roller of roller pair 16 and the upper plate of guide plate 15 are not shown together.

[0036] The alignment device 5 includes a first roller pair 17 and a second roller pair 18. The drive roller 19 of the first roller pair 17 and the drive roller 20 of the second roller pair 18 are rotatably supported in a carriage 21, coaxially aligned with each other. Each drive roller 19, 20 engages with a different counter-pressure roller 22. During alignment, the sheet 25 is sandwiched between the lower drive rollers 19, 20 and the two upper counter-pressure rollers 22. The drive roller 19 is driven by a first motor 11, and the drive roller 20 is driven by a second motor 12. Both motors 11 and 12 are electric motors.

[0037] If sheet 25 is tilted relative to the conveying direction 14, it is necessary to rotate sheet 25 about an imaginary vertical axis orthogonal to the conveying plane 13, i.e., to correct the tilt orientation of sheet 25. During tilt orientation correction, the two drive rollers 19 and 20 rotate asynchronously with different speeds to cause the aforementioned rotation of the clamped sheet 25.

[0038] When the two drive rollers 19 and 20 rotate synchronously with each other, if tilt orientation correction is not required, the sheet 25 is fed in the conveying direction 13 without sheet rotation.

[0039] In order to generate the adjustment movement 23 of the carriage 21 together with the drive rollers 19 and 20 (see Figure 4The device is equipped with a driver 24. The adjustment movement 23 is used for the lateral alignment of the sheets 25, and is performed parallel to the conveying plane 13 and orthogonal to the conveying direction 14.

[0040] Two counter-pressure rollers 22 (in) Figure 2a The rear section (obscured by the front) is rotatably supported in bracket 26 and can be pressed onto and depressed from the two drive rollers 19, 20 by the lifting movement 27 of bracket 26. Because bracket 26 is rotatably supported, the lifting movement 27 is an oscillating motion. The periodic lifting movement 27, performed at the sheet-feeding pace, is driven by a driver not shown in the figure. This driver can be a pneumatic cylinder, a linear driver, a lifting magnet, or a motor-driven cam mechanism.

[0041] The alignment device 5 also includes a first reflective light scanner 29 and a second reflective light scanner 30, which are placed or embedded in the transport plane 13. The two reflective light scanners 29 and 30 are located on a common straight line extending orthogonally to the transport direction 14. The two reflective light scanners 29 and 30 are arranged between the two roller pairs 17 and 18 and the printing station 3, and detect the edges of the sheets extending transversely to the transport direction 14 when the corresponding sheets are clamped in the roller pairs 16 and 17.

[0042] The alignment device 5 also includes a first row sensor 31 and a second row sensor 32, which are preferably CCD row sensors. The two row sensors 31, 32 are placed or embedded in the conveying plane 13 and are located on a common straight line parallel to the conveying direction 14. The rows of the corresponding row sensors 31, 32 extend orthogonally to the conveying direction 14. When the corresponding sheets are clamped in the roller pair 16, 17, the two row sensors 31, 32 detect the side edges of the sheets, such as... Figure 3 It is symbolically represented by the cross in the middle.

[0043] At least one detection device 8 includes a pair of reflected light scanners 33, which are structurally identical to the first reflected light scanner 29 and the second reflected light scanner 30. If multiple detection devices 8 exist according to a functionally preferred variant, each detection device 8 includes such a pair of reflected light scanners 33, which is advantageous for the aforementioned average value formation.

[0044] The detection of the sheet edge (front edge or rear edge) extending transversely to the transport direction 14 by the reflective light scanners 29 and 30 of the alignment device 5 and the reflective light scanners of the corresponding detection device 8 is symbolically represented by cross symbols in the figure.

[0045] According to Figure 5 , 6When the printing press is operated in the first mode shown in 12, large sheets (the longer of its two sides being longer than the maximum format width that the printing press can handle) pass through the press in portrait orientation. This allows for the largest possible printed surface area within a compact machine size.

[0046] According to Figures 2a to 4 When the printing press is operated in the second mode (7 to 11), small sheets (whose longer of two sides is shorter than the maximum format width the press can handle) pass through the press in a horizontal format. This increases the sheet throughput, thereby increasing the machine's productivity.

[0047] In both modes, the pages are aligned along their long edges. Whether the corresponding page 25 of the printing job passes through the machine in portrait or landscape format has the following effect on page alignment: in a printing job of the first page 34 in portrait format, alignment is performed on the side edge 28 of the corresponding first page 34; in a printing job of the second page 35 in landscape format, alignment is performed on the front edge 36 of the corresponding second page 35.

[0048] The following explanation, illustrated with various diagrams, details this point: Figures 2a to 4 The alignment of the second page 35 in the second mode is shown for front printing of the second page 35 facing upwards or towards the print head in the printing station 3.

[0049] Figure 2a and 2b As shown, the second page 35 passes through the first reflective light scanner 29 with its front edge 36, which is thereby activated and sends a first signal to the computer 9.

[0050] Figure 3 As shown, the second page 35 passes the second reflective light scanner 30 shortly after its leading edge 36, thereby activating the second reflective light scanner and sending a second signal to the computer 9. The computer 9 calculates the position and tilt orientation of the leading edge 36 of the second page 35 based on the time difference between the first and second signals, i.e., the time offset between triggering the first reflective light scanner 29 and triggering the second reflective light scanner 30. The two line sensors 31 and 32 each perform a measurement simultaneously with the triggering of the second reflective light scanner 30 and transmit the measurement value signal to the computer 9, which then calculates the position and tilt orientation of the side edges 28 of the second page 35.

[0051] Figure 4As shown, the alignment device 5 has aligned the second page 35 to the correct orientation for printing. To this end, the control device 10, based on calculated information regarding the position and tilt of the leading edge 36 and the side edges 28, drives the first motor 11 and the second motor 12, causing the drive rollers 19 and 20 connected to the motors 11 and 12 to rotate the second page 25 to a position where the leading edge 36 is orthogonal to the transport direction 14. Furthermore, the control device 10, based on information calculated by the computer 9, drives the driver 24, causing the driver 24 to laterally align the carriage 21, along with the drive rollers 19 and 20 and the second page 25 clamped by them, relative to a defined single side edge point 38 by means of an adjustment movement 23. This side edge point 38 is aligned with one of the line sensors 31 and 32 (here, the second line sensor 32, see...). Figure 3 The measurement point is the same.

[0052] Figure 5 and 6 The alignment shown in the first mode is used for front printing of the front side 39 of the first page 34, which is facing upwards or towards the print head during front printing at the printing station 3.

[0053] Figure 5 As shown, in the portrait format, the measurement process using the reflected light scanners 29 and 30 and the row sensors 31 and 32 of the alignment device 5 is the same as in the landscape format.

[0054] from Figure 6 It can be seen that the first sheet 34 is then aligned by means of roller pairs 17 and 18, so that its side edge 40 is parallel to the conveying direction 14. Here, the first sheet 34 is aligned at a defined single leading edge point 41, that is, at such a leading edge point 41, one of the two reflective light scanners 29 and 30 (here, the second reflective light scanner 30, see...) Figure 5 (This has been triggered by the front edge 42 of page 34 on the first page.)

[0055] exist Figures 7 to 10 In this example, taking the second page 35 in landscape format, a page measurement performed by means of one of the detection devices 8 is shown for alignment of pages for reverse printing by means of the alignment device 5. Here, the orientation of the back edge 43 of the page (also referred to as the first page edge 43) is not measured absolutely, but relative to the orientation of the front edge 44 of the page (also referred to as the second page edge 44). The advantage of this is that back edge measurement can be performed for all page formats that the machine can handle (minimum format, maximum format, and any intermediate format) without the need for relatively expensive line sensors.

[0056] The detection device 8 used includes a first sensor 45 and a second sensor 46, which are designed as low-cost reflective light scanners and together constitute the aforementioned reflective light scanner pair 33.

[0057] If the detection device 8 used for reverse printing during page measurement is one of two detection devices 8 arranged in the transport path 4 before the flipping device 7, then the leading edge 44 of the page is the leading leading edge 36 during front printing. However, if the detection device 8 is arranged after the flipping device 7 for page measurement, and the second page 35 is flipped in the flipping device 7, then the leading edge 44 of the page is the trailing trailing edge of the second page 35 during front printing.

[0058] Figure 7 As shown, the first sensor 45 is covered by the leading edge 44 of the page and thereby triggers a signal. Figure 8 As shown, the second sensor 46 is subsequently triggered by the leading edge 44 of the page, which is schematically represented in the figure by a cross symbol. Based on the signals from the two optical sensors 45 and 46, the computer 9 connected to them determines the position and tilt orientation of the leading edge 44 of the page.

[0059] Figure 9 As shown, the first sensor 45 is released by the trailing edge 43 of the page, thereby triggering a signal. Figure 10 As shown, the second sensor 46 is subsequently triggered by the rear edge 43 of the page.

[0060] Based on the existing values ​​in computer 9 for the position and tilt orientation of the front edge 44 of the page, the position and tilt orientation of the rear edge 43 of the page, and the conveying speed of the drive roller 47 of the detection device 8, computer 9 calculates the distance between the front edge 44 and the rear edge 43 of the page, as well as the angle between the front edge 44 and the rear edge 43 of the page.

[0061] The measured values ​​determined in the sheet measurement may deviate from the actual distance and angular dimensions due to various influencing factors, such as the roundness or diameter deviation of the drive roller 47. To compensate for these measurement errors, it is advantageous to perform multiple sheet measurements using multiple detection devices 8 and subsequently average them in a computer 9.

[0062] In the first mode, the measurement of the first page 34 in portrait format for its reverse printing alignment is performed in the same manner as previously described regarding the measurement of the second page 35 in landscape format in the second mode, and therefore requires no further description.

[0063] exist Figure 11As shown, in landscape format, after the second page 35 has been measured by means of the detection device 8 and is flipped by the flipping device 7, it is aligned for reverse printing by means of the alignment device 5 based on the measurement value obtained during measurement, such that the current rear edge 48 of the second page 35 (corresponding to the previous front edge 36 during front printing) is orthogonal to the transport direction 14. At its side edge 28, the second page 35 is aligned with its front printing (see...). Figure 4 The same side edge points 38 are aligned. Then, the reverse side 52 of the second page 35 (which faces upward after the page is flipped or when printing on the reverse side) is printed on the reverse side in printing station 3.

[0064] exist Figure 12 As shown, in portrait orientation, after the first page 34 has been measured by means of the detection device 8 and is flipped by the flipping device 7, it is aligned for reverse printing by means of the alignment device 5 based on the measurement value obtained during measurement, such that for reverse printing, the side edges 40 of the first page 34 are oriented parallel to the transport direction 14. At its current rear edge 49 (corresponding to the previous front edge 42 during front printing), the first page 34 is aligned with its front printing alignment (see...). Figure 6 The same edge points 50 (corresponding to the front edge point 41 when printing on the front side) are aligned. Then, the back side 51 of the first page 34 (facing up after the page is flipped or when printing on the reverse side) is printed on the reverse side in the printing station 3.

[0065] List of reference numerals in the attached diagram: 1-page entry device 2-page discharge device 3 printing stations 4 Conveying Path 5 Alignment Devices 6 Switching turnouts 7. Tilting device 8 detection devices 9 Computers 10 Control Devices 11 First Motor 12 Second Motor 13 Conveying plane 14 Conveying directions 15 guide plates 16-roller pair 17 (First roller pair of alignment device 5) 18 (Second roller pair of alignment device 5) 19 (first roller pair 17) drive roller 20 (second roller pair 18) drive roller 21 (alignment device 5) carriage 22 counter-pressure rollers 23 Adjusting Exercise 24 drives 25 pages 26 stents 27 Lifting and lowering motion 28 side edges 29 (First reflected light scanner of alignment device 5) 30 (Alignment device 5) Second reflective light scanner 31 (alignment device 5) first row of sensors 32 (Second row of sensors for alignment device 5) 33 (Detection device 8) Reflected light scanner Page 34 (first page, portrait format) Page 35, second page (landscape format). 36. Front edge (for horizontal format front printing) 37 (page 2, sheet 35) Front 38 side edge points 39 (Page 1, Sheet 34) Front 40 side edges 41 Forward Edge Point 42 Front edge (for front printing in portrait format) 43. First page edge / Back page edge (when measuring pages) 44. Second page edge / Lead edge of the page (when measuring pages) 45 (Reflected light scanner to 33) First sensor 46 (Reflected light scanner to 33) Second sensor 47 drive rollers (from detection device 8) 48 Back edge (when printing on the reverse side in landscape format) 49 Back edge (for vertical format reverse printing) 50 edge points 51 Back 52. Back side.

Claims

1. A method for operating a printing press in different modes, characterized in that, In the first mode, - The first page (34) is conveyed in a longitudinal format along the conveying plane (13) in the conveying direction (14). - The front side is printed on the front side (39) of the first page (34). - The first page (34) is flipped in the flipping device (7). - Reverse printing is performed on the back (51) of the first page (34). In this process, the first page (34) is aligned between the flip and reverse printing by means of the first roller pair (17) and the second roller pair (18). Between front printing and alignment, the orientation of the first page edge of the first page (34) relative to the second page edge is determined by the reflective light scanner of the detection device (8) (33), and Among them, the first edge of the first page (34) and the second edge of the second page extend laterally relative to the conveying direction (14), respectively. In the second mode, - The second page (35) is conveyed in a transverse format along the conveying plane (13) in the conveying direction (14). - Print the front side on the front side (37) of the second page (35). - The second page (35) is flipped in the flipping device (7). - Reverse printing is performed on the back (52) of the second page (35). In this process, the second page (35) is aligned between the flip and reverse printing by means of the first roller pair (17) and the second roller pair (18). Between front printing and alignment, the orientation of the first page edge (43) of the second page (35) relative to the second page edge (44) is determined by the reflective light scanner of the detection device (8) using the method of the detector (8). Among them, the first edge (43) and the second edge (44) of the second page (35) extend laterally relative to the conveying direction (14).

2. The method according to claim 1, characterized in that, When aligning the first page (34) according to the result of determining the orientation of the first page edge relative to the second page edge, the first motor (11) and the second motor (12) are controlled by the control device (10), the first motor (11) drives the first roller pair (17) and the second motor (12) drives the second roller pair (18).

3. The method according to claim 1, characterized in that, Between the front printing on the front side (39) of the first page (34) and the alignment of the first page (34), another reflective light scanner of another detection device (8) is used to determine the other orientation of the first page edge of the first page (34) relative to the second page edge.

4. The method according to claim 3, characterized in that, The computer (9) generates the average of the orientation determination results of the first page edge relative to the second page edge from the first page (34) using the reflected light scanner pair (33) and the orientation determination results of the first page edge relative to the second page edge from the first page (34) using the other reflected light scanner pair.

5. The method according to claim 4, characterized in that, When aligning the first page (34) according to the average value, the first motor (11) and the second motor (12) are controlled by the control device (10), the first motor (11) drives the first roller pair (17) and the second motor (12) drives the second roller pair (18).

6. The method according to claim 1, characterized in that, When aligning the second page (35) according to the orientation determination result of the first page edge (43) relative to the second page edge (44) of the second page (35), the first motor (11) and the second motor (12) are controlled by the control device (10), the first motor (11) drives the first roller pair (17) and the second motor (12) drives the second roller pair (18).

7. The method according to claim 1, characterized in that, Between the front printing on the front side (37) of the second sheet (35) and the alignment of the second sheet (35), the other orientation of the first sheet edge (43) of the second sheet (35) relative to the second sheet edge (44) is determined by means of another reflective light scanner of another detection device (8).

8. The method according to claim 7, characterized in that, The computer (9) generates the average of the orientation determination results of the first sheet edge (43) of the second sheet (35) relative to the second sheet edge (44) by means of the reflected light scanner pair (33) and the orientation determination results of the first sheet edge (43) of the second sheet (35) relative to the second sheet edge (44) by means of the other reflected light scanner pair.

9. The method according to claim 8, characterized in that, When aligning the second page (35) according to the average value, the first motor (11) and the second motor (12) are controlled by the control device (10), the first motor (11) drives the first roller pair (17) and the second motor (12) drives the second roller pair (18).

10. The method according to any one of claims 1 to 9, characterized in that, The front printing on the front (39) of the first page (34) and the reverse printing on the back (51) of the first page (34) were respectively carried out by inkjet printing, and The front printing on the front (37) of the second sheet (35) and the reverse printing on the back (52) of the second sheet (35) are respectively carried out by means of inkjet printing.

Images