Abstract
An apparatus and method for optional cross-folding of successively following, sequentially printed sheets on a first transport segment. A compressed air device comprises a first control element that is connected to a control unit for triggering or suppressing a compressed air blast from at least one exit opening in the compressed air device. A printed sheet is diverted into a second transport segment for the folding operation or a third transport segment for bypassing the folding operation. The latter empties downstream of folding rolls into the second transport segment at a joint segment point, at which a fourth transport segment adjoins in downstream direction. The third transport segment is longer than the second transport segment or can be operated at a lower speed than the second transport segment such that a first sequence of printed sheets successively following on the first transport segment is identical to a second sequence of the successively following printed sheets located on the fourth transport segment.
Claims
1. An apparatus for an optional cross folding of successively following, sequentially printed sheets, comprising: a first transport segment on which the sequentially printed, first printed sheets to be cross-folded and second printed sheets not to be folded, are transported successively in a guide plane and are respectively made available in a folding position; at least two folding rolls arranged on a first side of the guide plane which respectively include a rotational axis and together define a folding gap therebetween for cross folding the first printed sheets, wherein the rotational axes are oriented substantially parallel to each other and parallel to the guide plane; a compressed air device oriented substantially parallel to the rotational axes of the folding rolls on a second side of the guide plane and arranged opposite the first side of the guide plane and in a region of the folding gap, wherein the compressed-air device is connected to a compressed air source and a control unit, and includes at least one exit opening for focusing compressed air onto the folding gap; a second transport segment for cross-folded first printed sheets and a third transport segment for non-folded second printed sheets, wherein the first, second and third transport segments have a joint first segment point at which the first transport segment ends and the second and third transport segments start, wherein the joint first segment point is positioned on a line of intersection between the guide plane and a folding plane that extends through the at least one exit opening of the compressed air device; wherein the compressed air device includes a first control element connected to the control unit for optionally triggering or suppressing a compressed air blast coming from the at least one exit opening of the compressed air device, such that respectively starting with the folding position, one of the first printed sheets is moved for the folding operation into the second transport segment or one of the second printed sheets bypasses the folding operation and is moved to the third transport segment; wherein the third transport segment empties downstream of the folding rolls into the second transport segment, at a joint second segment point; and further including a fourth transport segment downstream of the joint second segment point that adjoins the second and third transport segments at the joint second segment point; wherein the third transport segment is longer than the second transport segment or can be operated at a slower speed than the second transport segment such that a first sequence of printed sheets, following successively on the first transport segment, is identical to a second sequence of first cross-folded sheets and second non-folded printed sheets following successively on the fourth transport segment.
2. The apparatus according to claim 1, wherein the third transport segment is essentially embodied longer than the second transport segment by half a sheet length of a first printed sheet to be cross-folded.
3. The apparatus according to claim 1, further including a mechanism for adjusting the length of the third transport segment arranged in a region of the third transport segment.
4. The apparatus according to claim 1, further including at least one of a light barrier and an image-detecting device, arranged in a region of the first transport segment and connected to the control unit, for detecting respective front edges of the first and second printed sheets transported on the first transport segment.
5. The apparatus according to claim 1, further including a first diverter arranged in the second transport segment and a first receiving device downstream of the first diverter arranged for receiving selected ones of the cross-folded first printed sheets.
6. The apparatus according to claim 1, wherein the folding rolls are arranged above the guide plane and the compressed air device is arranged below the guide plane.
7. The apparatus according to claim 1, further including a second diverter arranged in the fourth transport segment and a second receiving container arranged downstream of the second diverter for receiving selected ones of the cross-folded first printed sheets and the non-folded second printed sheets.
8. The apparatus according to claim 1, further including a joint drive connected to the control unit for the first, second, third and fourth transport segments.
9. The apparatus according to claim 1, further including a fifth transport segment downstream of the fourth transport segment and starting at a distance from the fourth transport segment, wherein the fifth transport segment includes a separate drive connected to the control unit to permit the fifth transport segment to operate at a different speed than the fourth transport segment.
10. The apparatus according to claim 9, further including an adjustment member for adjusting a spacing between the fourth and fifth transport segments.
11. The apparatus according to claim 1, further including at least one additional control element connected to the compressed air source and the control unit for changing at least one of a cross-sectional surface of the at least one exit opening of the compressed air device and the pressure of the compressed air to be supplied to the exit opening of the compressed air device.
12. A method for optionally cross-folding successively following, sequentially printed sheets, comprising: conveying at least a first printed sheet and a second printed sheet successively in a guide plane of a first transport segment for respectively making available the first and second printed sheets in a folding position; cross-folding the available first printed sheet along a folding line on a first side of the guide plane in a folding gap between at least two rotating folding rolls having separate rotating axes; prior to the cross-folding and starting from a second side of the guide plane, located opposite a first side, triggering a compressed air blast from at least one exit opening of a compressed air device which is coupled to a compressed air source and a control unit, focusing the compressed air blast in a region of the folding gap onto the first printed sheet made available in the folding position, transporting the available first printed sheet under effect of the compressed air blast and the rotating folding rolls from the guide plane to a second transport segment and, following the cross-folding, further transporting the cross-folded first printed sheet on the second transport segment; suppressing a compressed air blast that is focused onto the second printed sheet made available in the folding position and conveying the consequently non-folded second printed sheet to a third transport segment; conveying the non-folded second printed sheet that is moved to the third transport segment for a longer interval on the third transport segment than the cross-folded first printed sheet that is conveyed on the second transport segment; and following the cross-folded first printed sheet, moving the non-folded second printed sheet into a fourth transport segment that adjoins the second transport segment such that the sequence of the sequentially following printed sheets on the first transport segment is established for the cross-folded first printed sheets and the non-folded second printed sheets on the fourth transport segment.
13. The method according to claim 12, further including correspondingly changing the length of the third transport segment for a following production order with first and second printed sheets having at least one different format as compared to a previous production order.
14. The method according to claim 12, further including automatically detecting a front edge of the first and second printed sheets transported on the first transport segment and that based thereon, transmitting a corresponding information to the control unit, generating with the control unit a respective pulse at an instant of time of an optional triggering or suppressing of a compressed air blast from the at least one exit opening of the compressed air device which is focused on a respective one of the first and second printed sheets that has meanwhile moved to the folding position, and further transmitting the pulse to a first control element that is connected to the compressed air device and the compressed air source.
15. The method according to claim 12, further including removing cross-folded first printed sheets for control purposes from the second transport segment.
16. The method according to claim 12, further including removing at least one of defective cross-folded first printed sheets and non-folded second printed sheets from the fourth transport segment.
17. The method according to claim 12, further including transferring the cross-folded first printed sheets and the non-folded second printed sheets downstream of the fourth transport segment to a fifth transport segment, operated separately and at a distance from the fourth segment, and conveying the cross-folded first printed sheets and the non-folded second printed sheets on the fifth transport segment with a different speed than on the fourth transport segment.
18. The method according to claim 17, further including, for a following production order where at least one printed sheet has a different format than for the preceding production order, correspondingly changing a distance between the fourth transport segment and the fifth transport segment.
19. The method according to claim 12, further including the following steps: forming a first partial gap in the second transport segment upstream of a cross-folded first printed sheet, during a further conveying of a non-folded second printed sheet into the third transport segment, forming a second partial gap during a cross-folding of an additional first printed sheet belonging to the same production order, downstream of the additional first printed sheet and adjacent to the first partial gap, wherein the two partial gaps jointly form an insertion gap, and inserting the non-folded second printed sheet conveyed on the third transport segment into the insertion gap in a region of the fourth transport segment between the cross-folded first printed sheet and the additional cross-folded first printed sheet.
20. The method according to claim 19, further including making available successively in the folding position, one of the first printed sheets with a first sheet length, one of the second printed sheets with a second sheet length, and an additional first printed sheet with the first sheet length, wherein for first and second printed sheets of the same production order, the first sheet length is essentially twice as long as the second sheet length.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention is described further in the following with the aid of exemplary embodiments, showing in:
(2) FIG. 1 A schematic view from the side of a first embodiment of an inventive apparatus for the optional cross-folding of successively following, sequentially printed sheets;
(3) FIG. 2 An enlarged schematic representation of a cross-folding device for the inventive apparatus, shown at a somewhat earlier point in time than the instant shown in FIG. 1;
(4) FIG. 3 A schematic view from above onto the cross-folding device according to FIGS. 1 and 2, wherein a first printed sheet is located in a folding position in the cross-folding device, meaning between the folding rolls and the compressed-air device;
(5) FIG. 4 A schematic view from the side of the apparatus shown in FIG. 1, wherein all printed sheets have already been folded and/or are in the process of being folded;
(6) FIG. 5 A first snapshot of the apparatus according to FIG. 1, wherein all printed sheets to be processed further, e.g. for the later forming of partial book blocks, bypass the folding rolls and thus are not folded;
(7) FIG. 6 A second snapshot of the apparatus according to FIG. 1, taken at a later time as compared to FIG. 5;
(8) FIG. 7 An enlarged schematic representation, showing the downstream region of the apparatus in FIG. 1, in a second embodiment with an additional, fifth transport segment;
(9) FIG. 8 A representation according to FIG. 7 but showing a somewhat later processing instant.
DETAILED DESCRIPTION OF THE INVENTION
(10) FIG. 1 shows in a schematic view from the side a first embodiment of an inventive apparatus 1 for the optional cross-folding of printed sheets 2, 3, in this case the depicted sheets 3a, 2a″, 2b′, 3b, 2b″, 2c′, 3c, 2c″, 2d′, previously printed sequentially by a digital printing press, which can respectively be combined downstream of the apparatus 1 into partial book blocks 4a, 4b, 4c, 4d etc. that are indicated by a curved bracket in the various Figures. According to the representation, first printed sheets 2a″, 2b′, 2b″, 2c′ have already been folded in the apparatus 1 while a following first printed sheet 2c″ is in the process of being folded and another first printed sheet 2d′ must be folded during a following process step. Second printed sheets 3, for example the sheets 3a, 3b, 3c, are transported without being folded through the apparatus 1. The printed sheets 3a, 2a″ as well as a preceding, non-depicted printed sheet 2a′ are intended for the later forming of the first partial book block 4a, the printed sheets 2b′, 3b, 2b″ are intended for producing the second partial book block 4b, and the printed sheets 2c′, 3c, 2c″ are intended for producing a third partial book block 4c, which is also indicated by curved bracket in FIGS. 7 and 8. Furthermore shown are printed sheets 2, 3 which have already been removed from the apparatus 1 for control purposes or because they are defective, here the printed sheets 2x, 3y and 2z. Even though respectively three printed sheets are intended for forming a partial book block in this representation, a different number of printed sheets can also be used. Instead of removing a single printed sheet 2, 3, a different number of printed sheets can furthermore also be removed successively.
(11) Located upstream of the inventive apparatus 1 is a cutting and perforating unit, which is also not shown herein. Adjoining the cutting and perforating unit is a first transport segment 5 for the apparatus 1, which is connected to a cross-folding device 6 of the apparatus 1. At least on light barrier 7 and/or an image-detecting device 8 is arranged in the region of the first transport segment 5, directly in front of the cross-folding device 6.
(12) In contrast to FIG. 1, FIG. 2 shows an enlarged schematic representation of the cross-folding device 6 for the inventive apparatus 1, depicting the start of the folding of the first printed sheet 2c″. The first transport segment 5 comprises a guide plane 9 in which respectively a following printed sheet 2, 3 is supplied, here the following first printed sheet 2d′ to be cross folded. The transport plane ends in the cross-folding device 6, at a first segment point 10, from which the first printed sheet 2c″ is conveyed further to the cross folding.
(13) The guide plane 9, shown extending horizontally herein, can naturally also extend vertically or at any optional angle in space, thus permitting a plurality of structural options, depending on the concrete use conditions. Even though up to now and henceforth only a single printed sheet 2, 3 has been described and will be described in the Figures for reasons of simplicity, this refers respectively to at least one printed sheet 2, 3, meaning either a single printed sheet 2, 3 or several sheets placed one above the other.
(14) Two folding rolls 12 are arranged above the guide plane 9 on a first side 11 of the cross-folding device 6. These are respectively provided with a rotational axis 13 and between them form a folding gap 14 for folding the printed sheets 2 crosswise along a prepared folding line 15 (FIG. 3) or also along a non-prepared folding line. The rotational axes 13 of the folding rolls 12 are oriented substantially parallel to each other as well as parallel to the guide plane 9. Based on known order data or currently acquired data, the folding gap 14 can be adjusted manually or motorized, depending on the material thickness and the number of first printed sheets 2 to be cross folded, wherein the two folding rolls 12 can have identical or different diameters. To prevent, for example, a contact between the printed sheet and the downstream folding roll 12 and thus the stopping of the printed sheet, the diameter of the downstream folding roll 12 can be smaller than the diameter of the upstream folding roll 12.
(15) A compressed-air device 17 for the cross-folding device 6 is arranged on a second side 16 of the cross-folding device 6, which is opposite the first side 11 of the guide plane 9, and thus below the guide plane 9. The compressed-air device 17, oriented substantially parallel to the rotational axes 13 of the folding rolls 12, is provided with at least one, but preferably several, exit openings 18 (FIGS. 2, 3) focused onto the folding gap 14 for blowing compressed air 19. The compressed air device is connected via a compressed-air line 20 to a compressed-air source 21 which, in turn, is connected via a control line 22 to a control unit 23 of the apparatus 1. The compressed-air device 17 further comprises a first control element 24, e.g. embodied as magnetic valve, for admitting with compressed air 19 a first printed sheet 2, here the first printed sheet 2c″ in a folding position 25, as shown in FIG. 3, wherein the first printed sheet 2 in the folding position 25 is positioned flat between the two folding rolls 12 and the compressed-air device 17, or also for changing the time interval for admitting the at least one exit opening 18 with compressed air.
(16) Also shown in FIG. 3 are the printed sheets 2d′, 3d, 2d″ belonging to a partial book block 4d to be formed downstream of the apparatus 1 which, in the same way as the other first printed sheets 2, have respectively a first sheet length 2″ prior to the cross-folding and/or have respectively a second sheet length 3″ as for the other second printed sheets 3. The sheet lengths 2″, 3″ of associated printed sheets 2, 3 differ such that the first sheet length 2″ is substantially twice as long as the second sheet length 3″. Even though it is shown in FIGS. 1, 2, 7 and 8 in addition to FIG. 3 that a non-folded second printed sheet 3 is inserted between two cross-folded first printed sheets 2 or is intended to be inserted therein, it is in principle possible to create in the apparatus 1 an optional sequence of cross-folded first printed sheets 2 and non-folded second printed sheets 3.
(17) The compressed air device 17 for this example can comprise a second control element 26, e.g. embodied as slider or valve, for changing the cross section of the at least one exit opening 18, not shown herein, as well as a third control element 27 that can embodied as pressure-reducing valve, which is arranged in the compressed-air line 20 for changing the pressure of the compressed air 19 to be supplied to the at least one exit opening 18 (FIG. 2). The second control element 26 here can be connected to a slidable diaphragm provided with at least one recess, which is also not shown herein. By correspondingly moving this diaphragm, the at least one exit opening 18 is uncovered partially or totally or is completely covered, meaning the cross-sectional surface is changed. Of course, other suitable means can also be used for changing this cross-sectional surface. The control elements 24, 26, 27 are connected via separate control lines 22 to the control unit 23.
(18) A second transport segment 28 for cross-folded first printed sheets 2 starts at the first segment point 10 and extends through the folding rolls 12 of the cross-folding device 6 to a second segment point 29. A first diverter 30 is arranged along the second transport segment 28 for moving a cross-folded first printed sheet 2x to a first container 31, e.g. embodied for holding samples (FIG. 1).
(19) Adjoining the first transport segment 5 is a third transport segment 32 for non-folded second printed sheets 3, which also starts at the first segment point 10. The first segment point 10 is therefore a joint segment point for the first transport segment 5 ending therein and the second and third transport segments 28 and 32 which start at that point. The third transport segment 32 meets the second transport segment 28 at the second segment point 29 and ends there. Its length exceeds the length of the second transport segment 28. The third transport segment 32 furthermore comprises for the length adjustment a device 33 which, as shown in FIG. 1, comprises a sliding cylinder 33a having a cylinder rod 33b, as well as a guide roller 33c attached thereto that interacts with the third transport segment 32. Of course, a different suitable arrangement can also be used for the length adjustment of the third transport segment 32. The first segment point 10 is positioned on a line of intersection 34 between the guide plane 9 and a folding plane 35 (FIGS. 2 and 3) that extends through the folding gap 14 and through the at least one exit opening 18 of the compressed air device 17.
(20) At the second segment point 29, a fourth transport segment 36 adjoins the second and third transport segments 28, 32 (FIG. 1). The second segment point 29 thus forms a joint segment point for the second, third and fourth transport segments 28, 32 and 36. With a second diverter 37, arranged along the fourth transport segment 36, it is possible to divert cross-folded first printed sheets 2 and non-folded second printed sheets 3, in this case the printed sheets 2z and 3y but also waste paper, and move these to a second receiving container 38. Separate light barriers 7′ can also be arranged in front of the first and the second diverters 30, 37, so that the respective diverter 30, 37 can be switched precisely.
(21) According to the representation in FIG. 1, a sequence of a first printed sheet 2 to be folded, followed by a second printed sheet 3 not to be folded, followed by another first printed sheet 2 to be folded has been supplied to the apparatus 1 several times in succession. In the downstream region of the fourth transport segment 36 of the apparatus 1, these are the non-folded second printed sheet 3a and the cross-folded first printed sheet 2a″ which, jointly with a preceding, non-depicted cross-folded first printed sheet 2a′, were intended to form the first partial book block 4a. For this, the printed sheets 2a′, 3a, 2a″ were conveyed initially in this sequence with the first transport segment 5 to the folding position 25 (FIG. 3), in which they were positioned flat between the folding rolls 12 and the compressed air device 17. Starting with this folding position 25, the first printed sheets 2a′, 2a″ to be cross folded were respectively admitted with a compressed air blast 19′ from the at least one exit opening 18 in the compressed air device 17, as shown in FIG. 2 for the first printed sheet 2c″. Owing to this compressed air blast 19′, the printed sheets 2a′, 2a″ to be folded crosswise were respectively pressed with the center region between the folding rolls 12, in the process were diverted to the second transport segment 28, and were subsequently cross-folded with the aid of the folding rolls 12. The compressed air blast 19′ was triggered in that the control unit 23 has transmitted a corresponding control signal via the control line 22 to the first control element 24, thus providing compressed air 19 from the compressed air source 21. In contrast, such a compressed air blast 19′ was suppressed for the second printed sheet 3a, not to be folded, which has meanwhile been positioned in the folding position 25, so that this printed sheet was diverted and has bypassed the folding rolls 12 and was conveyed to the third transport segment 32. The decision, whether such a compressed air blast 19′ is triggered or suppressed, depends on the production orders that are deposited within the control unit 23. As the control unit 23 according to said production orders knows the number and the sequence of the first printed sheets 2 to be cross-folded and of the second printed sheets 3 not to be folded that are intended for the respective partial book blocks 4a, 4b, 4c, 4d, etc., an exact point in time for a respective pulse for triggering or suppressing the compressed air blast 19′ is determined with the at least one light barrier 7 and/or image-detecting device 8 arranged immediately before the cross-folding device 6, In case there is an image-detecting device 8, arranged additionally or alternatively to the at least one light barrier 7, the printed sheets 2, 3 can be identified advantageously and definitely by means of respective identification features, immediately before the cross-folding device 6.
(22) By conveying the non-folded second printed sheet 3a further to the third transport segment 32, a first partial gap 39a was generated in the second transport segment 28, upstream of the cross-folded first printed sheet 2a′, which is shown in FIG. 1 in the same way with a curved bracket upstream of the first printed sheet 2c′. This first partial gap 39a was followed by a second partial gap 39b, generated downstream of the first printed sheet 2a″ as a result of its folding operation, also shown in FIG. 1 with a curved bracket, downstream of the first printed sheet 2c″. The second partial gap 39b develops respectively because the first printed sheets to be cross folded, prior to reaching the folding rolls 12, initially enter with their front edge 2′ (FIGS. 2, 3) and nearly extend to the center of the third transport segment 32 before they are deflected into the folding rolls 12 by the effect of the compressed air blast 19′ hitting the sheet center, thus halving the original sheet length 2″ (see FIG. 3). The two partial gaps 39a, 39b had formed a joint insertion gap 39 between the two successively following first printed sheets 2a′, 2a″, as shown in FIG. 1, with the corresponding insertion gap 39, also shown with curved bracket, between the first printed sheet 2c′ currently positioned on the second transport segment 28 and the following printed sheet 2c″ that is in the process of being folded. Following its transport on the third transport segment 32, the non-folded second printed sheet 3a was inserted precisely into this insertion gap between the cross-folded first printed sheets 2a′ 2a″, in the region of the second segment point 29. The above-described operational sequence was identical to the one used for the printed sheets 2b′, 3b, 3b″ intended for the second partial book block 4b, wherein FIG. 1 shows precisely the situation in which the non-folded second printed sheet 3b has been inserted into the existing gap 39, between the two cross-folded first printed sheets 2b′ and 2b″. If printed sheets 2, 3 with at least one different format are processed for a following production order, as compared to a previous production order, the third transport segment 32 can be extended or shortened with the aid of the device 33, such that the non-folded second printed sheet 3 being conveyed on this transport segment 32 can advantageously also be inserted into the center of the gap 39 between the associated, cross-folded first printed sheets 2.
(23) The printed sheets 2, 3 are transported on all transport segments 5, 28, 32, 36 with the aid of the conveying elements 40, 40′, shown in FIG. 3, which are arranged on both sides of the printed sheets 2, 3 and are embodied, for example, as transport belts or bands. In FIG. 3, the conveying elements 40, 40′ are arranged below as well as above the printed sheets to be transported since the transport segments 5, 32, shown therein, only extend horizontally. With transport segments arranged vertical or at an angle, e.g. as is the case in the upstream region of the second transport segment 28 and the downstream region of the third transport segment 32, the conveying elements 40, 40′ can also be arranged on the side. In FIG. 3, the lower conveying elements 40′ are shown only on the third transport segment 32 for reasons of simplicity. Similar conveying elements 40, 40′ are also shown in FIGS. 7 and 8 and partially also in FIG. 2. The conveying elements 40, 40′ for the transport segments 5, 28, 32, 36 are operated at the same speed v.sub.1-4 and are provided with a joint drive 41, shown in FIGS. 7 and 8. Of course, the transport segments 5, 28, 32, 36 can also be provided with separate drives. Several deflection and/or tension rolls 42 are shown in FIG. 1 and in FIGS. 4 to 6 for the conveying elements 40, 40′ in the third transport segment 32, which are not shown further in the Figures. Similar deflection and/or tension rolls for the conveying elements can, of course, also be arranged in the second transport segment 28.
(24) According to FIG. 4, the apparatus 1 can also be used for processing only first printed sheets 2 to be folded. As a result, non-folded second printed sheets 3 need not be removed via the transport segment 32, meaning it remains inactive. Starting with an order having a sequence of partial book blocks with two, three and one first printed sheet 2 to be cross folded, for example, FIG. 4 shows from left to right the already cross-folded first printed sheets 2a′, 2a″, 2b′, 2b″, 2b′″, a first printed sheet 2c′ that is being raised in the center via a compressed air blast 19′ from the folding position in the direction of the folding rolls 12, as well as an additional first printed sheet 2d′ that must be cross-folded in accordance with a following production order. With this operating mode for the apparatus 1, a compressed air blast 19′ is always triggered when a first printed sheet 2 is in the folding position 25. As a result of the folding operation, a first gap 43 is respectively formed between the cross-folded first printed sheets 2, shown with curved bracket, which permits a non-problematic adding of the two diverters 30, 37 so that cross-folded first printed sheets 2 can be removed, if necessary, for the purpose of having a sample, or that defective cross-folded first printed sheets 2x, 2z can be removed, as shown in FIG. 4. The first printed sheets 2 which are not removed can be processed again downstream of the apparatus 1, for example to form partial book blocks that are not shown herein.
(25) FIG. 5 presents another operating mode for the apparatus, for which all printed sheets intended for the further processing, for example to be used for forming partial book blocks later on which are also not shown herein, meaning the second printed sheets 3 shown here as printed sheets 3a′, 3a″, 3b′, 3b″, 3b′″, 3c′, 3d′, 3d″, 3e′, 3e″, bypass the folding rolls 12 and are thus not folded. For this, the compressed air blast 19′ is respectively suppressed for the second printed sheets 3 positioned in the folding position 25—as is the case at present for the second printed sheets 3e′—so that the second printed sheets 3 can thus be conveyed by the third transport segment 32. In that case, the second printed sheets 3 are transported so-to-speak without any gap through the complete apparatus 1. However, defective second printed sheets 3 should still be removed, if necessary, as has happened already with the second printed sheet set 3z located in the receiving container 38. To remove another second printed sheet that is still located on the third transport segment 32, via the second diverter 37, a first printed sheet 2x that precedes this second printed sheet 3z and is located in the folding position 25 is deflected with the aid of a compressed air blast 19′ in the direction of the folding rolls 12 and thus into the second transport segment 28. In this way, a second removal gap 44 is formed in the third transport segment 32, between the preceding second printed sheet 3d″ and the additional second printed sheet 3z to be removed later to the second receiving container 38. FIG. 5 shows a first snapshot where this second removal gap 44 in the third transport segment 32 has already moved somewhat in the direction of the second segment point 29. FIG. 6, in contrast, shows a later snapshot depicting the start of the removal of the additional second printed sheet 3z, following the earlier detection of said printed sheet by the additional light barrier 7′ and the corresponding switching of the second diverter 37. In this snapshot, the second removal gap 44 used previously for switching the second diverter 37 is, as shown, already located downstream of the second removal deflector 37. The additional second printed sheets 3e′, 3e″, 3e′″, 3f′, 3f″, 3g′ and 3g″ follow in upstream direction.
(26) The first printed sheet 2x which, according to FIG. 5, is located on the second transport segment 28 and used for switching the second diverter 37 and thus for removing the additional second printed sheet 3z, was previously folded crosswise between the folding rolls 12. However, since this first printed sheet 2x will not be a component of the later partial book block and is earmarked for removal to the receiving container 31, it can be folded crosswise at any optional location. Also, the switching of the first diverter 30, following the detection of the first printed sheet 2x with the additional light barrier 7′, proves to be non-problematic since no other first printed sheet 2 directly precedes the first printed sheet 2x. FIG. 6 shows the first removed printed sheet 2x which is already located in the first receiving container 31. Through a corresponding earlier triggering of the compressed air blast 19′, focused onto the first printed sheet 2x, meaning prior to reaching its folding position 25, this first printed sheet 2x can also be deflected in the direction of the folding rolls 12, such that it passes non-folded through these rolls and later on can advantageously be used again. When starting up or shutting down the apparatus 1 and/or an inline digital printing press installed upstream of the apparatus, a first printed sheet 2x of this type is anyway part of the printing waste and thus is removed from the first receiving container 31.
(27) According to a second exemplary embodiment (FIGS. 7, 8) of the apparatus 1, a fifth transport segment 45 adjoins the fourth transport segment 36 in downstream direction, at a distance thereto, which serves to supply the printed sheets 2, 3 to a downstream arranged post-processing machine, not shown herein, for example a machine for forming partial book blocks 4a, 4b, 4c, 4d etc. As shown in FIG. 7, the printed sheets 2a″ and 2b′ are being conveyed on the fifth transport segment 45. The fifth transport segment 45 is also provided with conveying elements 40, 40′, comprising a separate drive 46, as compared to the joint drive 41 for the transport segments 5, 28, 32, 36. Owing to this separate drive 46, the fifth transport segment 45 can be operated with a speed v.sub.5 that differs from the speed v.sub.1-4 of the other four transport segments 5, 28, 32, 36.
(28) For example, the speed v.sub.5 is selected to be slower than the speed v.sub.1-4 if existing partial gaps must be minimized, e.g. the partial gap 39b shown in FIG. 7 between the two successively following, cross-folded first printed sheets 2b″ and 2c′. This also applies to minimizing residual partial gaps remaining of the previous partial gaps 39a, 39b. A first residual gap 39a′ can be seen, for example, downstream of the non-folded, second printed sheet 3c, just inserted into the previously generated gap 39 between the cross-folded first printed sheet 2c′ and 2c″, and such a second residual gap 39b′ that forms downstream of the cross-folded first printed sheet 2c″. A further second residual gap 39b′ is located in the downstream region of the fourth transport segment 36. Of course, depending on the post-processing operation downstream of the apparatus 1, the speed v.sub.5 can also be higher than the speed v.sub.1-4, for example if as shown in FIGS. 5 and 6 only non-folded second printed sheets 3 are conveyed on the third transport segment 32 for the apparatus 1 and if corresponding gaps are needed between the second printed sheets 3 for the further processing.
(29) During the transfer of a printed sheet 2, 3 from the fourth transport segment 36 to the fifth transport segment 45, as shown in FIG. 7 for the non-folded second printed sheet 3b, this sheet is initially conveyed by the conveying elements 40, 40′ of the fourth transport segment 36 until it is no longer clamped in along its back edge by these conveying elements 40, 40′. FIG. 7 shows precisely the following moment in which the front edge 3′ of the non-folded second printed sheet 3b is first clamped in by the conveying elements 40, 40′ of the fifth transport segment 45 and the transport segment 45 thus takes over the transport. The fifth transport segment 45 starts at a third segment point 47, at a distance to the transport segment 36, where a printed sheet 2, 3 is first admitted with a conveying pulse coming from the fifth transport segment 45. Since the respective printed sheet 2, 3 is only clamped in by the conveying elements 40, 40′ of one of the two transport segments 36, 45 during the transfer, it is possible to effectively avoid a bunching, crumpling or even destroying of these printed sheets 2, 3.
(30) Since the size of the spacing 48 between the two transport segments 36, 45 is thus decisive for the correct transfer of the respective printed sheet 2, 3 and because printed sheets 3 with different formats can be processed, depending on the production order, at least one of the two transport segments 36, 45, but advantageously both, are provided with an adjustment member 49 for changing the spacing 48. The adjustment member or members 49 can be operated manually or, advantageously, also motorized.
(31) FIG. 8 shows a somewhat later snapshot, as compared to FIG. 7, where the cross-folded first printed sheet 2b″ which follows the non-folded printed sheet 3b has just been released by the conveying elements 40, 40′ of the fourth transport segment 36 and has been clamped in along its front edge at the third segment point 47 by the conveying elements 40, 40′ of the fifth transport segment 45. As a result, the first cross-folded printed sheet 2b″ has been transferred to the fifth transport segment 45 and its conveying elements 40, 40′ take over the additional transport.
(32) As a result of the speed v.sub.5 of the fifth transport segment 45 being lower than the speed v.sub.1-4 of the transport segments 5, 28, 32, 36, the second residual gap 39b′ still existing in FIG. 7 between the printed sheets 3b and 2b″ in the downstream region of the fourth transport segment 36, has already been minimized in FIG. 8. Since the speed v.sub.5 of the first printed sheet 2b″ transported on the fifth transport segment 45 is lower than the speed of the following printed sheet 2c′ still conveyed on the fourth transport segment 36, the second partial gap 39b between these first printed sheets 2b″, 2c′, which has meanwhile moved to the downstream region of the fourth transport segment 36, will soon be minimized, wherein this also applies later on in the same way to the two residual gaps 39a′, 39b′ and all following gaps between the printed sheets.
(33) Triggered by the control unit 23, the separate drive 46 can be operated at different speeds, so that successively following, different speeds v.sub.5 can be realized for the fifth transport segment 45. In this way, the remaining gaps between printed sheets 2, 3 conveyed on the fifth transport segment 45 can, if necessary, have a uniform length.
(34) Of course, the connection of the control unit 23 for the apparatus 1 to the control elements 24, 26, 27 of the cross-folding device 6, illustrated herein respectively by a control line 22 in the form of a wire connection, with the light barriers 7, 7′, the image-detecting device 8, the two diverters 30, 37, and the drives 41, 46 for the transport segments 5, 28, 32, 36, 45 can also be embodied wireless. Naturally, additional sensors, drives or other devices such as the length-adjustment members can also be connected to the control unit 23, as shown with a dashed line in FIG. 1.
(35) It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and that the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
