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Description  |
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FIELD OF THE INVENTION
The present invention is related to a web-fed rotary printing press. In particular, the invention is related to movable folders and a former board arrangement for folding a plurality of printed ribbons in a web-fed rotary printing press.
BACKGROUND INFORMATION
In the production of newspapers, a plurality of paper webs is usually fed through an associated number of printing units to be printed on either one side or on both sides with a desired single or multi-color image. The printed webs are
afterwards longitudinally cut into ribbons which are fed to a former board section including one or more former boards for applying a longitudinal fold to the ribbons. Before passing over the former boards, the ribbons are usually superposed by means of
guide rollers before entering the former section and after exiting the former section, in order to obtain a desired paging and desired sectioning of the final newspaper.
After exiting the former board section, the superposed and longitudinally folded ribbons are then again superposed and fed to a downstream folder, in which the longitudinally folded superposed ribbons are cut and then folded crosswise into single
signatures which are transported to a mailroom section, in which the final newspapers are gathered, stacked and collated for further shipment.
From the prior art, it is known to use former board sections in which three pairs of former boards are arranged above each other and the superposed and longitudinally folded ribbons are fed to a subsequent folder which is fixedly installed in the
press room. The feeding of the folded and superposed ribbons to the folder is achieved by means of a plurality of guide rollers which are located below each of the former boards and around which each of the longitudinally folded superposed ribbons is
passed.
Due to the so-called radius effect, which is caused by the outer ribbon of a multi-layered ribbon passing over a diverting roller having a greater distance from the center of rotation of the roller compared with the inner ribbon of the
multi-layered ribbon, there is a certain likeliness of the occurrence of wrinkles and other defects of the printed ribbons which directly affect the printed image and general appearance of the newspapers. Moreover, there is also the danger of gussets or
even tears of the ribbons or the occurrence of tension variation or a ribbon weave which also detrimentally affect print quality. Another problem arising when passing a plurality of printed ribbons over a diverting roll is that there may occur a marking
of the freshly printed ink or a misregistration in the so-called cut-off register which actually defines the position at which the ribbons are cut crosswise in the folder section, in order to obtain a properly cut newspaper.
The main performance parameters which influence the probability of an occurrence of the above-described print affects are the paging of the newspapers, the diameter of the guide rollers, the angle of wrap of the ribbons around the guide rollers,
the length of the section leads, the number of the gathered sections and the gains of the nip rollers for pulling the ribbons over the former boards, which are located below each of the former boards and the ability of the nip rollers to hold the papers.
One of the main problems which arises during the operation of the printing press is that severe wrinkles which are likely to fold over or tear, do not only produce visible print affects, but may also result in folder jams which inevitably lead to
a shut-down of the printing press for a longer period of time, and therefore to a loss in output.
U.S. Pat. No. 5,775,222 purports to disclose a rotary printing press which includes folders which are movable via a yoke. One of the folders may be used as a primary folder, with the other folder being available as a replacement. UK 1,490,675
purports to discribe a method of interchanging folders in a printing machine, comprising lowering a folder to be removed from its operating position, moving the folder to be removed generally horizontally so as to remove it from the lowered position,
moving the folder to be installed generally horizontally to be lowered position, and raising the folder to the installed to its operating position.
SUMMARY OF THE INVENTION
Having outlined the state of the art and its attendant disadvantages, it is an object of the present invention to provide for a folder arrangement in a web-fed rotary newspaper printing press, which reduces the risk of the occurrence of severe
wrinkles in the images of the printed ribbons.
In accordance with a first embodiment of the present invention, a former board arrangement in a web-fed rotary newspaper printing press comprises a first and a second row of former boards, each row including a first, a second and a third former
board for longitudinally folding one or more ribbons passing over the former boards. The first row of former boards is arranged preferably obliquely above the second row of former boards, and a movable folder to which the longitudinally folded webs are
fed after exiting the former boards of the first and second row of former boards, is located below one of the former boards.
The combination of two rows of three former boards and a movable folder which may be located below any of the three former boards of the second row of former boards, reduces the likeliness of the occurrence of printed defects such as wrinkles and
gussets, tares, tension variations, ribbons weave and marking, significantly.
Moreover, it was found that the variations in the print-to-cut register of the printed signatures in the subsequent folder section are also reduced by the former board arrangement according to the present invention.
According to another aspect of the present invention, a plurality of guide rollers or gathering rollers is provided preferably below each former board, in order to divert the longitudinally folded ribbons exiting the former boards to the movable
folder, whereby all of the folded ribbons are preferably superposed by means of the guide rollers before entering the folder.
According to another aspect of the present invention, a plurality of superposed ribbons is passing over each of the former boards of the first and second rows of former boards, whereby the total number of superposed ribbons running over the
former boards of the second row of former boards is preferably larger than the number of ribbons passing over the former boards of the first row of former boards.
The advantage which can be obtained by using a different number of superposed ribbons running over each of the former boards lies in the increase in the variety of different sections and the paging of the newspaper, as four ribbons or half-webs
usually make up one section of the newspaper. By varying the number of ribbons passing over each former board, a desired arrangement of the sections in the newspaper can be obtained with a much higher flexibility. In this respect, it has also been
found that it is advantageous if the total number of superposed ribbons passing over the former boards of the second row of former boards is larger than the number of ribbons passing over the first row of former boards, as the severity of the wrinkles
and gussets and therefore the probability of print defects is being reduced.
According to another aspect of the present invention, a different number of superposed ribbons is passing over at least two of the former boards of the first row of former boards or of the second row of former boards, whereby in case of the first
row of former boards, two superposed ribbons may pass over two of the former boards of the first row of former boards. In this embodiment, the former board having the largest number of ribbons is preferably located on the very outside of the first row
of former boards.
In particular, it has shown to be advantageous if two superposed ribbons are passing over two of the former boards of the first row of former boards, and four superposed ribbons are passing over the remaining former board of the first row of
former boards. A further reduction of the severity of wrinkles and gussets may be obtained if the two former boards which are folding two of the superposed ribbons each, are located side-by side and the remaining former board folding four superposed
ribbons simultaneously is located at the very outside of the first row of former boards.
According to another aspect of the present invention, a different number of superposed ribbons is passing over at least two of the former boards of the second row of former boards. In this embodiment of the invention, the folding apparatus is
preferably located below the former board of the second row of former boards which folds the largest number of superposed ribbons, so that these ribbons are directly fed into the folder without running over guide rollers before entering the folder.
In accordance with another embodiment of the present invention, a movable folder is employed, which significantly simplifies the process of changing the path of the folded ribbons, by allowing the folder to easily move below the former board
folding the largest number of ribbons.
According to another embodiment of the present invention, preferably four superposed ribbons are passing over two of the former boards of the second row of former boards, and eight superposed ribbons are passing over the remaining former board of
the second row of former boards. In this embodiment, the two former boards for folding four superposed ribbons each are preferably located side by side, and the former board folding eight superposed ribbons is accordingly located at the very outside of
the second row of-former boards, preferably directly above the movable folder.
According to another embodiment of the present invention, the former boards of the first row of former boards are located substantially inline with the former boards of the second row of former boards, so that e. g. the tips of the former boards
of each row are arranged in substantially vertical planes running through the former boards.
According to another embodiment of the present invention, the former boards of the first and second row of former boards may also be located offset to each other, preferably such that the tips of the former boards of the first row of former
boards are located in substantially vertical planes which run between two adjacent former boards of the second row of former boards. By means of this tagged arrangement, the number of guide rollers for directing the superposed ribbons exiting the former
boards of the first row of former boards, and therefore the likeliness for the occurrence of wrinkles and gussets can be further reduced.
In accordance with another embodiment of the present invention, a movable folder assembly includes a folder slidingly supported on a pair of rails and an actuator for moving the folder on said pair of rails.
The actuator preferably includes a hydraulic cylinder and a control unit for controlling said hydraulic cylinder. Preferably, the cylinder rod of the hydraulic cylinder is rigidly fixed to the platform and the body of the hydraulic cylinder is
secured to the folder. Moreover, the hydraulic cylinder is preferably configured so that the cylinder body is the movable piece. In a preferred embodiment, this is accomplished by forming a bore through the length of the cylinder rod, and attaching the
hose to the end of the rod. In this manner the hoses remain stationary as the folder is moved. This simplifies the layout of hydraulic hoses as compared with conventional hydraulic cylinder arrangements in which the hydraulic hoses move back and forth
as the cylinder moves.
The movable folder assembly may be employed in combination with the former board arrangement described above, or may be used with conventional former board arrangements. The use of a movable folder significantly reduces a time required to re-web
the folder in the event of a folder failure because, by moving a replacement folder into the same position as the original folder, there is no need to reallign the webs to compensate for a change in folder position. In addition, when used in conjunction
with the former board arrangements described above, the use of movable folders significantly simplifies the process of changing the path of the folded ribbons, by allowing the folder to easily move below the former board folding the largest number of
ribbons.
In accordance with a further aspect of this embodiment, the folder is supported on said rails by bearings. Preferably, the bearings are linear bearings, and most preferably, the folder is supported on at least one of said rails by dual-type
linear bearings. The use of linear bearings provides a number of advantages including improved load distribution, and a reduced susceptabilty to failure due to contaminants (e.g. dirt) in or on the bearings and/or rails.
The folder assembly may also include a preset device for providing a plurality of preset folders positions along the rails. Preferably, the preset device is an absolute encoder.
In accordance with a still further aspect of this embodiment of the present invention, the movable folder includes a first folder and a second folder slidingly supported on the pair of rails. In one embodiment, the first folder is secured to the
second folder so that the first and second folders move together along the rails. In an alternative embodiment, the first and second folders move separately along the rails.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of preferred embodiments, when read in conjunction with the accompanying drawings, wherein
like-elements have been designated with like-reference numerals and wherein:
FIG. 1 is a schematic view of an exemplary embodiment of a newspaper printing press according to the present invention,
FIG. 2 is a more detailed schematic view of the former board arrangement according to the present invention with two rows of three former boards, guide rollers and a schematic view of a movable folder,
FIG. 3 is a schematic view of the former board arrangement of FIG. 2 which is set up in a first configuration,
FIG. 4 is the former board arrangement of FIG. 2, which is set up in a second configuration,
FIG. 5 is the former board arrangement of FIG. 2, which is set up in a third configuration,
FIG. 6 is the former board arrangement of FIG. 2, which is set up in a fourth configuration,
FIG. 7 is the former board arrangement of FIG. 2, which is set up in a fifth configuration, and
FIG. 8 is the former board arrangement of FIG. 2, which is set up in sixth configuration according to the preferred embodiment of the invention, and
FIG. 9 and FIG. 10 are prior art former board arrangements which are set up in two exemplary configurations.
FIG. 11 shows a movable folder assembly in accordance with a preferred embodiment of the present invention.
FIG. 12 shows a more detailed review of the folder and rail system of FIG. 11.
FIG. 13 shows an exploded view of folder and rail system of FIG. 12.
FIGS. 14a and 14b show a single-type linear bearing of FIG. 13.
FIGS. 15a and 15b show a dual-type linear bearing of FIG. 13.
DETAILED DESCRIPTION OF THE REFERRED EMBODIMENTS
As it is shown in FIG. 1, a newspaper printing press 1, e g. a lithographic web-fed rotary printing press, comprises a plurality of printing units 2 for printing a single or a multi-color image on a variety of webs 4 which are supplied by reel
stands 6. The reel stands 6 are preferably located in the basement of a press room. After the printing operation in the printing unit 2, the webs 4 are fed to a former board arrangement 8 according to the present invention, which is preferably located
in the center of the newspaper printing press 1, but may also be located at one side of the press or at an end portion thereof.
The former board arrangement 8 of the present invention which is shown in more detail in FIG. 2, includes a first row 10a of three former boards 12, 14, 16 and a second row 10b of three further former boards 18, 20 and 22.
After the printing operation in the printing units 2, and before entering the former board arrangement 8, the webs 4 are preferably longitudinally cut into single ribbons or half webs 24, which are then fed to the former boards 12, 14, 16 and 18,
20, 22 of the first and second row 10a and 10b of the former boards via rollers 26 located on top of each former board 12, 14, 16, 18, 20, 22.
According to an exemplary embodiment of the invention, a plurality of ribbons 24 may be arranged on top of each other before feeding them to the former boards 12 to 22, whereby four ribbons or half webs 24 usually make up one section of a
newspaper. The superposition of the ribbons 24 may be achieved by known gathering or take-off rollers 28, as they are indicated in FIG. 1.
After passing the former boards 12 to 22, the multi-layer or superposed ribbons 24 are fed to a pair of nip rollers 30 which apply a longitudinal fold to the superposed ribbons 24. After passing the nip rollers 30, the longitudinal folded
superposed ribbons are passed over a plurality of guide rollers 32 which guide the ribbons 24 towards a folder 34. The folder 34 is movable relative to the former boards 12 to 22, as it is indicated by arrow 36 in FIG. 2. The folder 34 may be a
conventional folder which cuts the superposed ribbons 24 entering the folder 34 into a plurality of newspapers 38, which may afterwards be folded crosswise and located on a conveyor belt 40 by a known fan wheel arrangement 42. The conveyor belt 40
transports the papers 38 as a shingled stream of papers 38 to a further processing section (not shown), e. g. a mailroom.
A number of different configurations for passing the ribbons 24 over the former boards 12 to 22 will now be discussed with respect to FIGS. 3 through 8.
FIGS. 3 to 5 show a first, second and third configuration, in which 16 pages, i.e. four superposed ribbons 24 each printed on both sides, are passed over each of the former boards 12 to 22 of the first and second row 10a, 10b of former boards.
Depending on the position of the folder 34, the likeliness of the occurrence of wrinkles and gussets of each configuration is given by a severity index, which amounts to 30 in case of the configurations of FIGS. 3 and 4. In the configuration of FIG. 5,
however, the severity index is reduced to 26.5, as applicant has found, which may be a result of the configuration of guide rollers and the successive superposition of webs 24 one by one from only one side and the straight feeding into the folder 34.
Turning to the fourth, fifth and sixth configuration of FIGS. 6, 7 and 8, in which the same total number of ribbons 24 is fed to the folder 34, but in which due to a different paging of the newspaper, eight pages are fed over former boards 14 and
16 of the first row 10a of former boards and 32 pages, i. e. eight sections are passing over former board 22 of the second row 10b of former boards, the severity index is reduced from 26.5 for the FIG. 6 configuration to 25.5 for the FIG. 7 configuration
and further down to 23.0 for the FIG. 8 configuration. As indicated above, the reduction of the severity index may be caused by the different positions of the folder 34 changing from the very left in FIG. 6 to superposition of the folded superposed the
very right in FIG. 8 and by the successive ribbons below the former board 22 in FIG. 8, starting from only one (the left) side.
However, there may be other reasons for the reduction of the severity index in case of FIG. 8 configuration, such as the straight feeding of the heaviest section (32 pages) running straight into the folder 34.
In comparison, in the prior art devices (FIGS. 9 and 10) having a non-movable or fixed folder 134, the severity indexes amount to 35 for FIG. 9 and 35.5 for FIG. 10, although the total number or ribbons fed to the folder 134 is the same as the
configurations using a former board arrangement 8 according to the present invention shown in FIGS. 3 to FIG. 8.
Moreover, sliding folders allow an easy replacement of a folder or the introduction of a spare folder on a long press with more than one folder position. Preferably, the folders slide on rails. Moreover, movement of the folders may be actuated,
for example, with hydraulic or motor actuators. In addition, in order to improve ribbon handling performance, the folders may be moved while the press is running.
As a person skilled in the art will recognize, the severity indexes for the different configurations of FIGS. 3 to 8 of the former board arrangement 8 according to the present invention are always lower than the severity index of the prior art
former board arrangement, shown in FIGS. 9 and 10.
It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof, and that the invention is not limited to the specific
embodiments described therein, in particular to the number of configurations shown in FIGS. 3 to 8. Accordingly, other configurations, e.g. a staggered arrangement of the first row of former board 10a relative to the second row of former board 10b or a
certain offset of two adjacent former boards in each row may be conceivable, which may lead to an even further reduction of the severity index. Moreover, the number of ribbons 24 passing over the former boards 12 to 22 may also be varied in any possible
and conceivable way, in order to obtain a desired paging and sectioning of the newspaper.
According to a further embodiment of the invention, two rows of former boards with three former boards each arranged above each other may be combined with two folders plus independently driven former rollers and nip rollers associated with the
former boards, in order to allow each former board to feed either of the | | |
