GB2311254A

GB2311254A - Process and apparatus for controlling automatic printing plate change processes

Info

Publication number: GB2311254A
Application number: GB9705897A
Authority: GB
Inventors: Bernd Lindner; Thomas Moller; Hubert Hofmann
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1996-03-23
Filing date: 1997-03-21
Publication date: 1997-09-24
Anticipated expiration: 2017-03-21
Also published as: JPH09254361A; FR2746342B1; FR2746342A1; GB2311254B; GB9705897D0; DE19611530C1; JP3002153B2

Description

1 2311254 - 1 PROCESS AND APPARATUS FOR CONTROLLING AUTOMATIC PRINTING

PLATE CHANGE PROCESSES The invention relates to a process and apparatus for controlling an automated printing plate change process.

In offset sheet printing presses, devices for semi- or wholly-automatic printing plate change processes are known in which a printing plate, which should be fed to the plate cylinder, is installed in a magazine or in a cassette incorporated as a protection in front of the _.printing units. After actuation of a corresponding actuation element, under programme.control a corresponding position of the plate cylinder is adopted, is whereafter the print end of the printing plate tensioned on the plate cylinder is released by releasing the clamping of the corresponding clamping rail at the print end. Thefl by reverse turning of the plate cylinder, the feeding out of the used printing plate takes place into a corresponding receiving device or the storage chamber of the printing plate changer. After the printing plate by reverse turning of the plate cylinder has been fed substantially completely into the corresponding changer, the release of the clamping of the print start (actuation of the clamping rail arranged relative to the print start) takes place, whereafter the printing plate can be pulled out by hand or by corresponding devices (transport rollers) from the print start rail. Then the feeding in of the new printing plate takes place by feeding the edge arranged relative to the print start into the opened print start rail. After checking the correct register (abutment of the printing plate against electrically interrogatable register pins), the print start rail is closed (clamping) and the new printing plate, by forwards turning of the plate cylinder, is drawn on to this until the print end of the printing can be fed in by a corresponding device (settable on pressing-on roller) into the tensioning rail arranged for the print end.

Finally, the tensioning of the newly drawn on printing plate takes place by means of a corresponding tensioning movement of the print end rail.

Such a device for automatic changing of printing plates is known, in this connection, from DE 43 39 344 Cl. In this specification, the corresponding working steps for ---anautomatic change process of a printing plate are also described.

As well as the fully or partly automatically running working steps for changing a printing plate, additionally interrogation is also necessary during the initiated process in order to guarantee a smooth procedure. In this connection noted to be of predominant importance 30 already is the checking of the register correct lay-up of the printing plate front edge by means of so-called electrically interrogatable register pins. As known from DE 43 38 664 C2, this sort of electrically interrogatable register pin can be used not only for triggering a is clamping process, but in accordance with this previously known process, there takes place in addition to this also the determination of whether the printing plate located in the rail has left this (after opening of the clamping slot). The further running of the programme for changing the printing plate is, in this connection, interrupted so long until the printing plate fed by reverse turning of the plate cylinder into the corresponding receiving device has left the grasping region or the register pins in the print start rail. By means of this additional interrogation, it can be avoided, in particular, that an initially fed out printing plate is immediately again by forwards turning of the plate cylinder drawn on to this, because, for example, it has been forgotten to remove the printing plate by hand from the grasping region of the print start rail.

From DE 94 11 254 U1, a device for checking an automatic printing plate change process is known in which for checking an orderly feed process of a printing plate by means of driven transport rollers and freely rotatably ---mountedcounter pressure rollers, a sensor system is provided sensing the movement of the counter pressure rollers. Since, in this device, the determination of the turning of the freely rotatable counter pressure roller is sensed, it can be determined whether especially a used printing plate has been fed out by a predetermined minimum distance from the plate cylinder or the clamping rail arranged relative to the print start. On non-.

determination of turning of the counter pressure roller or if the counter pressure roller has not carried out the provided minimum number of rotations, an error report can be generated and the printing plate change process is interrupted.

Despite these additional,interrogations known from the state of the art, which can be carriedout during an automatic printing plate change process and the further working steps introduced or not introduced in dependence on the results, a plurality of problem possibilities are nevertheless present by means of which, in particular, the devices serving for the semi- or wholly-automatic printing plate change can be damaged, sometimes substantially. Thus, it can occur, for example, that with a semiautomatic printing plate change process in which an operator only after introducing the corresponding command is to pull out the old printing plate by a distance from the protection and then has to feed in the new printing plate into the print start rail, the change programme is left with corresponding inputs at the control panel of the printing press. If then particularly another operator is to carry out the change process which has been begun, then it can arise on account of a not yet fully tensioned printing plate on reverse turning of the plate cylinder, that jamming of the printing plate takes place and deformation on the devices serving for printing plate change in the protection. Also, it is not possible without further ado with the controls which have up till now become known for automatic changing of printing plates, for example already after the putting into operation of the printing press, to determine whether the printing plate has actually been changed or not at each plate cylinder. Also during a printing plate change, any emergency commands triggered (e.g. emergency stop) stop the initiated change process immediately, so that in certain situations or not completed working steps, a new initiation of the change process should not in any case arise. This has its basis in the already indicated above possibilities with respect to the damage to the printing plate and/or the elements serving for the change process. To be seen as particularly critical, in this connection, is the phase in which a printing plate fed to the plate cylinder is fixed at the clamping rail arranged relative to the print start, but where the print end of the printing plate has, however, not yet been grasped by the corresponding tensioning device or fixed on this. Particularly in this case, it is easily envisageable that a reverse turning of the plate cylinder by a given amount would lead to damage to the printing plate which was only held on one side, because this eventually would be jammed against the ink applicator rollers.

The present invention seeks to provide a process as well as apparatus for carrying out a plate change process in such a fashion so that while avoiding the previously noted disadvantages of the state of the art, changing of printing plates is guaranteed and, in particular, a change process initiated once at a printing unit can be taken up again even after interruptions of a safety related nature, or which can be carried out anew from the beginning.

According to a first feature of the invention, there is provided a process for controlling an automatic printing plate change process in a printing press, in which, after the input of at least one control command, the carrying out of a sequence of working steps takes place of moving to given plate cylinder positions, clamping/releasing or tensioning/detensioning of the printing plates as well as the turning of the plate cylinders in given directions and through predetermined angular amounts, wherein, by means of at least one working step of the sequence of working,steps provided for the change process, an actuation of at least one condition indicator is generated, and a deactivation of this condition indicator takes place after carrying out a working step following further on in the sequence of steps constituting the change process.

In carrying out this automatic printing plate change process, for example in one of the stores containing the control program carrying out the individual working steps of the change process, at the beginning or on the ending of certain working steps so- called markers are set. Thus coordinated to at least one working step in the sequence of working steps provided for the change process, an activation of at least one condition indicator is generated. Deactivation of this condition indicator takes place after carrying out a further working step subsequently in the sequence of the changed process. These markers directed to particular conditions (condition indicators) are, following ending or at the beginning of an immediately or directly following working step, extinguished again in the corresponding store of the control. This means, in other words, that a particular area of the overall plate change process is paramatrised depending upon the condition by the mark(s) i.e. particular, and particularly hand triggerable, processes are only introducible or carriable out in dependence upon the presence or the non-presence of a set/non-set marker. By means of a set marker is to be understood here in particular the setting of a bit into the store of the control carrying out the change process. According to a further development of the invention, it can be provided, in this connection, to arrange relative to given phases or sections between appropriate working steps of the change process different markers, i.e. the possibility of restarting the change process or of changing a printing plate by hand with corresponding manual triggering of the individual clamping and tensioning processes in dependence on the set or of the non-set marker to configure this variably.

In a further development, it can be provided that during an automated change process, for example after the clamping of the printing plate front end, a corresponding marker is set and this is first then to be unset or to be extinguished once the print end of the printing plate is clamped in the corresponding tensioning rail and has been tensioned. If it arises prior to the fixing of the print end of the printing plate by switching off the press or trigger of an emergency off command to a programme interruption of the change process, then by interrogation of the marker set it can be avoided that the change programme can be started again from new or that moving of the plate cylinder with the object of reaching a predetermined position leads to damage of the not fully -tensioned printing plate.

According to a further development of the invention, it is provided to store given markers or at least one marker also in remanent fashion, which can occur in particular by storage in an E2PROM or in a so-called flash EPROM. Accordingly, even with a total switching off of the printing press, it is guaranteed on putting it back into action that in dependence on the set or not set marker, certain operating commands for the initiation of a change process can be released or can be wholly suppressed. Furthermore, it is possible, on putting the printing press into operation, to illustrate at the control panel of the printing press a display with reference to the completely finalised change process in the individual printing units. A particular advantage of the process j accordance with the invention as well as the device for carrying out the process is, in this connection, that no additional sensors or other signal emitters are provided. The regions explained in the subsequent exemplary embodiments and coordinated to individual working step intervals, in which particular commands are locked or freed, arise, in this connection, of themselves and only in dependence on the facts as to whether for a marker setting working step also the respectively arranged marker removing subsequent working step has been carried out.

The explanation of the exemplary embodiment takes place, in this connection, with reference to the accompanying diagram which shows the working steps to be carried out in an automatic printing plate change process in combination with two markers provided. The printing plate change process described in this connection, is -preferably carried out in combination with a change device of the type set out above, e.g. as in the prior art specifications referred to.

After, for example, at the control panel of the not illustrated printing machine, a menu for changing the printing plates has been chosen, by initiating an operating command at the corresponding printing unit, programme "plate change printing unit nII is actuated. Then by means of the control of the printing press, there results the moving of the plate cylinder in this printing unit to a predetermined position in order to free the print end of the printing plate present on the plate cylinder. This moving or positioning process is reproduced, in this connection, in Figure 1 by "PE position". In this position, actuation devices installed fixed with respect to the frame can cooperate with corresponding units on the plate cylinder in order, in particular, to loosen the clamping and to free the print end of the plate. This working step carries in Figure 1, in this connection, the notation "PE rail open". From this point in time or after carrying out this working step, the trailing end of the printing plate is no longer held by the PE rail. Thereafter, the feeding out of the used printing plate via its trailing end takes place. The moving of the so-called print start position, which is reflected in Figure 1 under the working step "PS position". In this connection, the plate cylinder turns backwards for so long until the trailing end of the printing plate located on the plate cylinder has been fed substantially wholly into a corresponding change device.

After effecting the working step "PS position" by means of the control the working step "PS rail open,, is triggered, which means that now, by the actuation devices again fixed with respect to the frame, the clamping at the PS rail is released. With a fully automatic printing plate changer the feeding out of the used printing plate takes place by driving corresponding transport rollers or in a semi-automatic printing plate changer the used printing plate is pulled out by hand a distance from the changer constructed as protection.

After the used printing plate has been fed out or taken from the PS rail, there then takes place in particular in connection with electrically interrogatable register pins the release of the working step "PS rail close,,, wherein - 10 a printing plate fed in either wholly automatically via transport rollers or by hand into the opened print start rail, once it is in register correct position, is clamped. Thereafter, the move to the print end position takes place by triggering the working step "PE position" wherein, for this, the plate cylinder is turned forwards so long until the new printing plate has been fully drawn on around the exterior periphery. After introduction of the end of the drawn on printing plate into the tensioning rail arranged for the print end, the working step "PE rail close" is actuated by the control, whereafter then, in particular, at the control panel of the printing press, the indication "plate change printing unit n ended" can be displayed and a corresponding change process in an adjacent printing unit can be triggered.

Now in accordance with the invention, it is provided that on carrying out the working step "PE rail open,, in the control or in a store of the control, a marker is set, whereby a retraction or extinction of this marker takes place first in the next but one working step, namely the working step "PS rail open". In addition to all this, it is likewise provided, after the closing of the print start rail triggered by the electrical register interrogation "PS rail close' to set a marker yet again which likewise in the next but one working step "PE rail close" is retracted again or extinguished. In Figure 1 in the column below the condition indicator "marker", which gives that the plate is not fully drawn on to the plate cylinder, two intervals limited between the setting or the respective unsetting are characterised with the reference symbol "A". In accordance with the invention, it is in this case provided that with correspondingly set marker during the interval 'W' by means of the control controlling the change process, no renewed change process can be triggered, particularly after a programme interruption or on putting the press into operation anew. The once initiated change process must then be continued by corresponding command input by hand until one gets to that working step in which the set marker is withdrawn. In the exemplary embodiment in accordance with Figure 1, this means that, for example, a programme break cause following the carrying out of the working step "PE rail open thus during the working step "PS position" must be ended with the working step "PS rail open,, in order to unset the set marker again. On non-fulfilment of this condition (marker still set), no new plate change process can be initiated so that also corresponding reverse is turning of the plate cylinder with corresponding damage to the printing plate located thereon as well as to the corresponding change devices is not triggerable.

According to a further development of the invention, it is provided that in a store constructed especially as an E2PROM or flash PROM in dependence upon the carrying out of given working steps, a so-called remanent marker is set or retrieved. In the present exemplary embodiment, this means that the actuation of the working step "close PE rail", both a setting of the remanent marker and also the corresponding retrieval of the marker (interval "A") takes place. The set remanent marker, by which the interval characterised in Figure 1 with the reference sign "B" takes place first in dependence on the carrying out of the working step "PE rail open" in combination with the setting of the marker by which the interval with the reference sign 'W' is limited. In Figure 1 it is accordingly detectable that the remanent marker is set exactly within the interval "B" of the working process mentioned if a printing plate is located on the plate cylinder. Correspondingly this remanent marker is an indication for this condition, which can be indicated correspondingly on an indicator unit on the control panel of the printing press.

Claims

1. A process for controlling an automatic printing plate change process in a printing press, in which, after the input of at least one control command, the carrying out of a sequence of working steps takes place of moving to given plate cylinder positions, clamping/releasing or tensioning/detensioning of the printing plates as well as the turning of the plate cylinders in given directions and through predetermined angular amounts, wherein, by means of at least one working step of the sequence of working steps provided for the change process, an actuation of at least one condition indicator is generated, and a deactivation of this condition indicator takes place after carrying out a working step following further on in the sequence of steps constituting the change process.

2. A process according to Claim 1 wherein activation of the condition indicator takes place by storing information and the deactivation of the condition indicator by extinguishing this information in the respective later working step.

3. A process according to Claim 1 or 2 wherein by means of at least one activated condition indicator, locking against the release of given commands and, in particular, the carrying out of a complete printing plate change process in at least the selected printing unit, takes place, and this locking is relieved with activation of the respective condition indicator.

4. A process according to any one of the preceding Claims wherein the activation/deactivation of a condition indicator occurs in at least two directly or indirectly sequentially following working steps, wherein the condition indicator is activated across the period of time in which the printing plate is not wholly drawn on to the plate cylinder.

5. A process according to any one of the preceding Claims wherein the activation/deactivation of a condition indicator takes place in at least two direct or indirectly sequentially following working steps, wherein the condition indicator is activated over the period of time in which the printing plate is wholly drawn on to the plate cylinder.

6. A process according to any one of the preceding Claims wherein the activation/deactivation of a condition indicator takes place in at least two directly or indirectly sequentially following working steps and the storage of this condition indicator takes place in non20 volatile fashion.

7. A process according to any one of the preceding Claims wherein at least one activated/deactivated condition indicator is illustrated on a display device.

8. A process for controlling an automatic printing plate change process substantially as hereinbefore described with reference to the accompanying drawing.

9. Apparatus for carrying out a process according to any one of the preceding Claims and consisting of a control connected to a printing press by which, for changing a printing plate after the input of at least one control command, the carrying out of a sequence of working steps effecting moving to given plate cylinder positions, the clamping/releasing or tensioning/ detensioning of the printing plate as well as the rotation of the plate cylinder in given directions and through predetermined angular amounts can be triggered wherein the control has at least one storage unit in which, on carrying out a working step, a condition indicator is activatable, and following corresponding carrying out of a coordinated further working step, this 10 condition indicator is again deactivatable.

10. Apparatus according to Claim 9 wherein the store connected to the control is a non-volatile rewritable storage medium.

is

11. Apparatus according to Claim 9 or 10 and including means for displaying the status of at least one activatable/deactivatable condition indicator on a display device of the printing press.