Claims
- 1. A controlled process for producing a previous ink zone profile corresponding to a previous printing job in at least one printing stand of a printing press and for changing from the previous ink zone profile corresponding to the previous printing job to a subsequent ink zone profile corresponding to a subsequent printing job, said subsequent printing job being carried out immediately subsequent to said previous printing job, said printing stand comprising a printing plate cylinder for positioning a printing plate, an ink reservoir for holding a supply of ink and an inking mechanism for transferring the ink between said ink reservoir and said printing plate during operation of said printing stand, said inking mechanism comprising a plurality of inking rollers, a plurality of individually adjustable ink zone metering devices, at least one ink fountain roller positioned adjacent said plurality of individually adjustable ink zone metering devices, and at least one ink transfer roller for transferring the ink between said ink fountain roller and at least one of said plurality of inking rollers, each of said plurality of individually adjustable ink zone metering devices defining a substantially corresponding ink zone of said at least one printing stand, said process comprising the steps of:
- (a) producing the previous ink zone profile by initiating operation of:
- said printing plate cylinder,
- said plurality of inking rollers,
- said at least one ink transfer roller, and
- said at least one ink fountain roller, and
- by transferring ink from said ink reservoir to said printing plate cylinder via forward a route of travel which extends:
- from said ink reservoir through at least one of said plurality of individually adjustable ink zone metering devices,
- thereafter to said at least one ink fountain roller,
- thereafter to said at least one ink transfer roller,
- thereafter to said plurality of inking rollers, and
- thereafter to said printing plate cylinder;
- (b) printing said previous printing job;
- (c) terminating the printing of said previous printing job; and
- (d) changing to subsequent ink zone profile corresponding to said immediately subsequent printing job by the process comprising the steps of:
- (e) calculating at least one previous parameter characterizing said previous ink zone profile;
- (f) calculating at least one subsequent parameter characterizing said subsequent ink zone profile;
- wherein said subsequent printing job is carried out immediately subsequent to said previous printing job; and
- (g) adjusting at least one of said plurality of adjustable ink zone metering devices, in accordance with said calculated previous and said subsequent parameters, and operating said inking mechanism to thereby change the ink zone profile in said printing stand from said previous ink zone profile to said subsequent ink zone profile, said operation of said inking mechanism comprising the transfer of ink from said inking mechanism and through at least one of said plurality of individually adjustable ink zone metering devices to said ink reservoir;
- wherein said adjusting and operating step (g) comprises the steps of:
- (g1) adjusting at least one of said plurality of individually adjustable ink zone metering devices to transfer ink from said inking mechanism to said ink reservoir;
- (g2) initiating operation of:
- said printing plate cylinder,
- said plurality of inking rollers,
- said at least one ink transfer roller, and
- said at least one ink fountain roller;
- to transfer ink from said printing plate cylinder to said ink reservoir via a reverse route of travel which extends:
- from said printing plate cylinder to said same plurality of inking rollers as in step (a),
- thereafter to said same at least one ink transfer roller as in step (a),
- thereafter to said same at least one ink fountain roller as in step (a),
- thereafter through at least one of said same plurality of individually adjustable ink zone metering devices as in step (a), and
- thereafter to said same ink reservoir as in step (a);
- (g3) continuing operation of said printing plate cylinder, said plurality of inking rollers, said at least one ink transfer roller and said at least one ink transfer roller until said plurality of inking rollers have a defined base ink layer deposited thereon;
- (g4) adjusting at least one of said plurality of individually adjustable ink zone metering devices to transfer ink from said ink reservoir to said inking mechanism;
- (g5) initiating operation of said at least one ink transfer roller to thereby transfer ink, on the surface of said at least one ink transfer roller, to said inking mechanism through at least one of said plurality of individually adjustable ink metering devices;
- (g6) continuing operation of said at least one ink transfer roller until said subsequent ink zone profile is established; and
- (h) printing said immediately subsequent printing job.
- 2. The process according to claim 1, wherein said previous and subsequent parameters calculated in said steps (e) and (f) comprise, respectively, a value indicative of the volume of ink existing in said inking mechanism from said previous printing job, and a value indicative of the volume of ink required in said inking mechanism for execution of said subsequent printing job.
- 3. The process according to claim 1, wherein said plurality of ink zone metering devices adjustably transfer ink between said ink reservoir and said inking mechanism in accordance with individual ink zone setting, and wherein said previous parameter comprises a derived function of said individual ink zone settings used for said previous printing job.
- 4. The process according to claim 3, wherein said derived function comprises an arithmetic average of said previous individual ink zone settings.
- 5. The process according to claim 3, wherein, using said derived function of said previous ink zone settings, a required number of inking mechanism actuations for the removal of ink from said inking mechanism necessary to the realization of said base ink layer therein is determined, and wherein said steps (g2) and (g3) of operation of said inking mechanism are carried out for said determined required number of inking mechanism actuations.
- 6. The process according to claim 5, wherein said inking mechanism additionally comprises adjustable vibrator roller means for transferring ink strips between said ink reservoir and at least one of said plurality of inking rollers, the lengths of said transferred ink strips being adjustable, and wherein, during said steps (g2) and (g3) of achievement of said base ink layer, said vibrator roller means is adjusted so as to transfer an ink strip of maximum length from said at least one of said plurality of inking rollers to said ink reservoir.
- 7. The process according to claim 6, wherein, during said steps (g2) and (g3) of achievement of said base ink layer, said printing stand is additionally actuated to thereby remove ink from said inking mechanism through the carrying out of printing of ink on an ink receiving medium.
- 8. The process according to claim 5, wherein, during said steps (g2) and (g3) of achievement of said base ink layer, said printing stand is actuated to thereby remove ink from said inking mechanism through the carrying out of printing of ink on an ink receiving medium.
- 9. The process according to claim 5, wherein said inking mechanism additionally comprises adjustable vibrator roller means for transferring ink strips between said ink reservoir and said rollers, the lengths of said ink strips being adjustable, wherein, during said steps (g4), (g5) and (g6 ) of transferring ink from said ink reservoir to said inking mechanism, said ink metering devices and said ink strip lengths are adjusted to desired values to establish said subsequent ink profile, wherein, using said desired values of said ink zone settings and said ink strip lengths, a required number of inking mechanism actuations for establishment of said subsequent ink profile is determined, and wherein said step (g5) of transferring ink from said ink reservoir to said inking mechanism is carried out for said determined required number of inking mechanism actuations.
- 10. A controlled process for producing a previous ink zone profile corresponding to a previous printing job in at least one printing stand of a printing press and for changing from the previous ink zone profile corresponding to the previous printing job to a subsequent ink zone profile corresponding to a subsequent printing job, said subsequent printing job being carried out immediately subsequent to said previous printing job, said printing stand comprising a printing plate cylinder for positioning a printing plate, an ink reservoir for holding a supply of ink and an inking mechanism for transferring the ink between said ink reservoir and said printing plate during operation of said printing stand, said inking mechanism comprising a plurality of inking rollers, a plurality of individually adjustable ink zone metering devices, at least one ink fountain roller positioned adjacent said plurality of individually adjustable ink zone metering devices, and at least one ink transfer roller for transferring the ink between said ink fountain roller and at least one of said plurality of inking rollers, each of said plurality of individually adjustable ink zone metering devices defining a substantially corresponding ink zone of said at least one printing stand, said process comprising the steps of:
- (a) producing the previous ink zone profile by initiating operation of:
- said printing plate cylinder,
- said plurality of inking rollers,
- said at least one ink transfer roller, and
- said at least one ink fountain roller,
- and by transferring ink from said ink reservoir to said printing plate cylinder via a forward route of travel which extends:
- from said ink reservoir through at least one of said plurality of individually adjustable ink zone metering devices,
- thereafter to said at least one ink fountain roller,
- thereafter to said at least one ink transfer roller,
- thereafter to said plurality of inking rollers, and
- thereafter to said printing plate cylinder;
- (b) printing said previous printing job;
- (c) terminating the printing of said previous printing job; and
- (d) changing to subsequent ink zone profile corresponding to said immediately subsequent printing job by the process comprising the steps of:
- (e) calculating at least one previous parameter characterizing said previous ink zone profile;
- (f) calculating at least one subsequent parameter characterizing said subsequent ink zone profile;
- wherein said subsequent printing job is carried out immediately subsequent to said previous printing job; and
- (g) adjusting at least one of said plurality of adjustable ink zone metering devices, in accordance with said calculated previous and said subsequent parameters, and operating said at least one ink transfer roller to transfer ink, on the surface of said at least one ink transfer roller, to thereby change the ink zone profile in said printing stand from said previous ink zone profile to said subsequent ink zone profile, said operation of said at least one ink transfer roller comprising the transfer of ink from said printing plate cylinder to said ink reservoir, in at least one of said ink zones in said at least one printing stand, via a reverse route of travel which extends from:
- said printing plate cylinder to said same plurality of inking rollers as in step (a),
- thereafter to said same at least one ink transfer roller as in step (a),
- thereafter to said same at least one ink fountain roller as in step (a),
- thereafter through at least one of said same plurality of individually adjustable ink zone metering devices as in step (a), and
- thereafter to said same ink reservoir as in step (a);
- said at least one previous parameter characterizing said previous ink zone profile calculated in said step (e) comprising a previous volumetric indicator indicative of the volume of said previous ink zone profile remaining in said inking mechanism in each of said plurality of ink zones as a result of said previous printing job; and
- said at least one subsequent parameter characterizing said subsequent ink zone profile calculated in said step (f) comprising a subsequent volumetric indicator indicative of said subsequent ink zone profile required in said inking mechanism in each of said plurality of ink zones for said subsequent printing job; and
- wherein said adjusting step (g) comprises the additional steps of:
- (g1) calculating, for each of said plurality of ink zones, a volumetric difference indicator indicative of the change of ink volume in said inking mechanism between the ink volume remaining from said previous printing job and the ink volume required for said subsequent printing job;
- (g2) adjusting and operating each of said plurality of ink metering devices in accordance with the corresponding ink zone volumetric difference indicator calculated in step (g1);
- (g3) continuing operation of said printing plate cylinder, said plurality of inking rollers, said at least one ink transfer roller and said at least one ink transfer roller until establishment of said subsequent ink zone profile in said inking mechanism is substantially achieved; and
- (h) printing said immediately subsequent printing job.
- 11. The process according to claim 10, wherein said step (g2) of adjusting said plurality of ink metering devices comprises the additional steps of:
- (g2A) calculating, for each of said ink zones and using the corresponding ink zone volumetric difference indicator, a number of inking mechanism actuations required to substantially produce said corresponding ink zone volumetric difference in said inking mechanism; and
- (g2B) determining the maximum number of inking mechanism actuations calculated in said step (g2A);
- wherein the continuing operation of said inking mechanism performed in said step (g3) is terminated when the number of inking mechanism actuations executed substantially equals the maximum number of inking mechanism actuations determined in said step (g2B).
- 12. The process according to claim 11, wherein said inking mechanism additionally comprises adjustable vibrator roller means for transferring ink strips between said ink reservoir and at least one of said plurality of inking rollers, the lengths of said ink strips being adjustable, and wherein said process comprises the additional steps of:
- determining whether any of said ink zone volumetric difference indicators calculated in step (g2A) indicates a removal of ink from an ink zone corresponding thereto in order to accomplish said change in ink volume in said inking mechanism; and
- if said removal of ink from said corresponding ink zone is so indicated by said corresponding ink zone volumetric difference indicator, adjusting said vibrator roller means so as to transfer an ink strip of maximum length from said at least one of said plurality of inking rollers to said ink reservoir.
- 13. The process according to claim 11, wherein said inking mechanism additionally comprises adjustable vibrator roller means for transferring ink strips between said ink reservoir and at least one of said plurality of inking rollers, the lengths of said ink strips being adjustable, and wherein said process comprises the additional steps of:
- determining whether the following Conditions exists:
- Condition:
- (1) none of said ink zone volumetric difference indicators calculated in said step (g2A) indicates a removal of ink from an ink zone corresponding thereto in order to accomplish said change in ink volume in said inking mechanism; and
- (2) at least one of said ink zone volumetric difference indicators calculated in said step (g2A) indicates an addition of ink from an ink zone corresponding thereto in order to accomplish said change in ink volume in said inking mechanism; and;
- if said Condition does exist, adjusting said vibrator roller means so as to transfer, from said ink reservoir to said at least one of said plurality of inking rollers, said corresponding volumetric ink zone difference at least within said maximum number of inking mechanism actuations determined in said step (g2B).
- 14. The process according to claim 13, wherein said process comprises the additional steps of:
- (i) determining, for each of said plurality of ink zones, a corresponding difference between said required number of inking mechanism actuations calculated in said step (g2A) and said maximum number of inking mechanism actuations determined in said step (g2B);
- (j) determining which, if any, of said corresponding differences determined for each of said plurality of ink zones in said step (i) are nonzero;
- (k) for substantially all nonzero corresponding differences determined for each of said plurality of ink zones in step (j), determining a corresponding equilibrium ink zone setting for said corresponding ink zone metering device which will establish an equilibrium condition wherein the considerable transport of ink between said ink reservoir and said inking mechanism is substantially prevented; and
- (i) during execution of said maximum number of inking mechanism actuations determined in said step (g2B) and executed in said step (g3), setting each of said corresponding ink zone metering devices to said corresponding determined equilibrium ink zone settings for a number of inking mechanism actuations substantially equal to said corresponding differences.
- 15. The process according to claim 14, wherein said equilibrium ink zone settings are determined empirically as a function of said previous volumetric indicator.
- 16. The process according to claim 14, wherein said equilibrium ink zone settings are determined by simulation as a function of said previous volumetric indicator.
- 17. The process according to claim 13, wherein said process comprises the additional steps of:
- (i) determining, for each of said plurality of ink zones, a corresponding difference between said required number of inking mechanism actuations calculated in said step (g2A) and said maximum number of inking mechanism actuations determined in step (g2B);
- (j) determining which, if any, of said corresponding differences determined for each of said plurality of ink zones in said step (i) are nonzero;
- (k) for substantially all nonzero corresponding differences determined for each of said plurality of ink zones in step (j), determining a corresponding equilibrium ink zone setting for said corresponding ink zone metering device which will establish an equilibrium condition wherein the considerable transport of ink between said ink reservoir and said inking mechanism is substantially prevented; and
- (i) during execution of said maximum number of inking mechanism actuations determined in said step (g2B) and executed in said step (g3), setting each of said corresponding ink zone metering devices to said corresponding determined equilibrium ink zone settings for a number of inking mechanism actuations substantially equal to said corresponding differences.
- 18. The process according to claim 17, wherein said equilibrium ink zone settings are determined empirically as a function of said previous volumetric indicator.
- 19. The process according to claim 17, wherein said equilibrium ink zone settings are determined by simulation as a function of said previous volumetric indicator.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 3707695 |
Mar 1987 |
DEX |
|
BACKGROUND OF THE INVENTION
This is a continuation of application Ser. No. 07/166,556, filed on Mar. 10, 1988, now abandoned.
1. Field of the Invention
On rotary printing presses, particularly on offset rotary printing presses, it is necessary to feed a very thin and uniform ink film to a printing plate wetted by a wetting agent. For the high-viscosity printing inks normally used currently, a complex inking unit equipped with many rollers is generally required to produce this thin and uniform ink film. A result of the high viscosity of the inks currently used and the many rollers employed in the inking unit is that it takes longer to achieve an appropriate ink distribution in the inking unit to ready it for printing.
2. Description of the Prior Art
U.S. Pat. No. 4,660,470, entitled "Inking Unit Pre-Adjustment Method" and issued Apr. 28, 1987, which corresponds to German Laid Open Patent Appln. No. DE-OS 33 38 143, describes a process for presetting the inking unit, wherein the process starts with an empty, washed inking unit. The objective is to produce a defined basic ink layer 4 to 5 microns thick on all the rollers, so that the desired ink profile can be applied to them in a second process step. The second step is thereby either performed when printing has started, or else the printing is delayed until after the definitive achievement of the desired ink profile and ink gradient.
In practice, when there is a job change, the new printing job is set up and run without washing the inking unit. Additionally, in many cases, the inking unit is not washed before long periods of inactivity, e.g., before weekends or holidays. Such practices are made possible by so-called "overnight inks". In actual practice, therefore, regardless of the quantity of ink and the ink distribution of the previous job, the machine is positioned to the new setting, and the zonally existing excess quantities of ink are removed from the inking unit by the printing of a large number of waste sheets, if the new job requires zonally less ink than the previous job.
As noted above, U.S. Pat. No. 4,660,470 (issued Apr. 28, 1987) described as process for establishing a desired ink zone profile in a rotary printing press. This U.S. patent hereby expressly incorporated herein by reference, as if the contents thereof were fully set forth herein.
The published technical papers "Possibilities and Margins of the Computerized Analysis of Offset Inking Units (I)", Prof. Dr.--Ing. Helmut Rech, druck print 8/1984, pp. 522-523; "Possibilities and Margins of the Computerized Analysis of Offset Inking Units (II)", Prof. Dr.--Ing. Helmut Rech, druck print 9/1984, pp. 578-582; "Possibilities and Margins of the Computerized Analysis of Offset Inking Units (III)", Prof. Dr.--Ing. Helmut Rech, druck print 10/1984, pp. 659-660; "Possibilities and Margins of the Computerized Analysis of Offset Inking Units (IV)", Prof. Dr.--Ing. Helmut Rech, druck print 11/1984, pp. 725-726; and "Rechnergestutzte Entwicklung von Farbwerken in Druckmaschinen", Prof. Dr.--Ing. Helmut Rech, Der Polygraph 9, 1981, pp. 699-709 discuss the use of computer assisted iterative simulations, modelings, and empirical or semi-empirical methods for establishing ink transfer characteristics and parameters in rotary printing presses.
Issued U.S. Pat. No. 4,441,819 (issued Apr. 18, 1984) and issued U.S. Pat. No. 3,958,509 (issued May 25, 1976), issued European Patent No. 0 081 739, published European Patent Appln. No. 0 095 606 and the prior published technical documents "Flow of Information in the System", "Description of Commands, Store", "Description of Commands, Zones Identical-Gradual Adjustment", "Description of Commands, Cassette: Read In", and "Heidelberg CPC" (Publication No. HN 2/43.e), all of which have been previously published by Heidelberger Druckmaschinen AG, D-6900 Heidelberg, Federal Republic of Germany, discuss the use of a control stand computer to control the printing process and methods by which appropriate ink zone settings and appropriate ink strip lengths may be chosen, preset into the control stand computer, and/or adjusted during the printing process. The above mentioned U.S. Pat. Nos. 4,441,819 and 3,958,509 are additionally expressly incorporated by reference herein.
A principal object of the present invention is, therefore, the provision of a process for the production of a defined ink distribution (or new ink profile) in the inking unit appropriate to a new (or subsequent) printing run, in which the new profile is achieved without the need to completely empty and wash the inking unit.
This object may be achieved by adoption of the embodiments set forth below.
In a first embodiment, the modification of the ink profile takes place before the printing of the subsequent run and includes two steps. First, the ink profile present in the inking unit from the previous printing job is removed (or leveled to a uniform thickness) while the machine is still rotating by: initially, closing the ink dosing (or metering) elements, and transporting the quantities of ink present zonally in the inking unit, as a function of the profile, back into the ink duct by means of a specified number of rotations (which may, according to the invention, be determined by simulative, empirical or semi-empirical methods well known in the art), until a uniformly small and defined thickness of ink, independent of the profile (e.g., a base ink layer), is present on all the rollers. Thereafter, the ink profile required for the subsequent printing job is established in the inking unit by a zonal adjustment of the ink metering elements by adjusting the length of the ink strip which is transferred into the inking unit (hereinafter referred to as the "ink strip length" or, more colloquially, as used by artisans in the printing field, the "ink strip width"), and by means of a defined number of rotations of the inking unit (determined via simulative, empirical or semi-empirical methods), so that an appropriate profile can be established under precisely defined conditions.
A primary advantage of the present invention is that a precisely defined base ink layer can be produced on all rollers directly from the ink profile remaining after the preceding job, starting from any given profile, and that the subsequent establishment of a new profile is accomplished automatically, that is, with very little intervention or judgement required on the part of the printing press operator. The printing press operator is thereby able to set up a new printing job in the shortest possible time and without major effort or expense, eliminating the use of a large number of waste sheets and the major time and expenditures involved in cleaning the inking unit. The ink strip to be transferred into the inking unit by means of a vibrator inking unit, for example, can be the length of the ink strip transferred by the vibrator roller.
An inking unit with a uniformly low and defined ink thickness on all the rollers independent of the profile is achieved by setting the vibrator roller for a specified number of machine rotations with closed ink dosing elements, preferably with a setting to invoke the maximum ink strip length, and according to the ink separation characteristics of the particular ink employed, that ink is transported back into the ink duct (or ink reservoir). Since the zonal ink profile gradually disappears, the closer it gets to the inking rollers, during the return of the ink, in addition to the removal of the ink gradient, the zonal profile is also eliminated. The next process step can either take place immediately afterward, or be delayed in relation to the first. That is, some time interval may be imposed between the achievement of a uniform ink profile in the inking mechanism due to the removal of ink from the inking mechanism and the subsequent process step of setting up a new ink profile appropriate to the subsequent printing job. In the determination of the required number of rotations of the inking unit, as described below, the required ink gradient in the inking unit is taken into consideration, so that the printer operator need only start the job change, and in the shortest possible time, and without manual intervention, he can start to print the new job.
The process according to another embodiment, as a function of the quantitative zonal ink balance between the previous printing job and the subsequent printing job, makes it possible to produce the new ink profile in the ink unit directly, ready for the print run, without the production of an intermediate uniform base ink layer. For this purpose, before beginning to print, first the values stored in the computer for the zonal adjustment of the dosing elements and the length of the ink strip used for the previous print job are compared with the values input into a computer memory for the zonal adjustment of the ink dosing elements and the length of the ink strip used for the subsequent print job, and the zonal differences are determined from the ink zone values. These values, supplemented by the zonal quantities stored by the inking unit, are transported from the rotating inking unit back into the ink reservoir, depending on whether the difference in the quantity of ink is positive or negative. The number of inking unit rotations required for the purpose until the zonal differences are equalized is initially determined first, and only then are the ink dosing elements adjusted and the length of the ink strip transferred into the inking unit for the subsequent printing job. During this adjustment, before the beginning of the print run, no ink is transported out of or into the inking unit when printing has been stopped.
The process steps take place automatically, so that here too, an ink distribution in the inking unit can be achieved which is appropriate to the printing run.
To obtain the correct ink gradient in the inking unit, this process also makes it possible to withdraw somewhat more ink than strictly necessary during the first part of the activation of the inking unit, and during the remainder, to add the same amount of ink back again. The correct ink gradient is thereby adjusted automatically, which fact can be taken into consideration in the determination of the number of rotations or zonal adjustments.
In zones with a satisfactory balance, no change is made. For example, ink can be extracted during the first half of the number of machine rotations to be executed, and the same amount of ink can be added back again in the second half. The correct ink gradient is thereby adjusted automatically, which fact can be taken into consideration in the determination of the number of rotations or zonal adjustments.
The determination of the required number of machine rotations can be based, for example, on a maximum ink strip length, the closing of the zones with positive ink differences and the opening of the zones with negative ink differences to the new position. Naturally, other combinations are also possible, e.g., the determination of an ink strip length which results in the same number of machine rotations for the zones with positive quantitative ink differences as for the zones with negative quantitative ink differences.
The ink profile corresponding to the new printing job and the corresponding ink strip length can be determined, for example, by gauging the printed proof or the printing plate, and inputting the result via a data line or a data medium, or it can be manually input and stored by the printer.
For the characteristics described above, it is to be assumed that the zonal ink differences are used for the calculation of the ink strip length and the zonal adjustments required. Also taken into consideration is the fact that the ink roller unit stores a zonal quantity of ink which is a function of the zonal ink consumption, which is greater than the quantitative ink differences between the two printing jobs. For example, it is possible, in the computation of the ink strip length, to determine an average value of the ink quantities stored in the inking unit between zones with positive and negative differences.
There may also be provided advantageous process steps to remove the current ink profile, whereby the ink dosing elements are moved into closed positions, the ink duct rollers are preferably set to maximum ink strip length, the vibrating roller movement is initiated, a defined number of inking unit rotations are executed, the vibrating roller movement is stopped, and the inking unit continues to rotate a defined number of rotations until the end of the ink profile removal.
During this process, the establishment of the ink profile required for the subsequent print job is accomplished by individual process steps, whereby the ink metering elements are adjusted by zones to the required ink profile, the ink duct rollers are set to the determined ink strip length, the vibrator roller motion is initiated, a defined number of inking unit rotations are executed, and the paper flow and printing begin, or the vibrator roller motion is stopped, or the vibrator roller motion is stopped and the machine is stopped.
The present invention also provides for an accelerated removal of the current ink profile, while the paper flow continues, by means of the following process steps: with simultaneous paper flow, the ink duct rollers are preferably set to maximum ink strip length; the vibrator roller motion is initiated; the paper flow and printing are initiated: a defined number of machine rotations are executed; the vibrator roller movement is stopped; at the end of the ink profile removal, the machine continues to rotate for a determined number of rotations without paper flow; and thereafter the profile is established as described above.
There is also provided an alternative embodiment, wherein the paper flow continues, but without the return of ink to the ink duct, and wherein an accelerated removal of the current ink profile is accomplished by means of the following process steps; the paper flow and printing are started: a defined number of machine rotations are executed; the paper flow and printing are stopped; at the end of the ink profile removal the machine continues to rotate for a determined number of rotations without paper flow; and thereafter the profile is established as described above.
The invention also provides a second embodiment for the execution of an automatic sequence of operation, in which a removal of the current ink profile and a simultaneous establishment of the ink profile required for the subsequent print job are carried out simultaneously by means of the following individual process steps: the ink dosing elements are zonally adjusted according to the differential ink quantities determined; the ink duct rollers are set to a calculated ink strip length: vibrator roller movement is initiated: the mathematically determined number of inking unit rotations for the simultaneous removal of the old profile and establishment of the new profile are executed; the ink metering elements for the subsequent print job are zonally adjusted to the required ink profile: the ink duct rollers are set to the required ink strip length; and the paper flow and printing are initiated; or, alternatively, the vibrator roller movement is stopped and the machine is shut down.
In general, the invention features a controlled process for changing an ink zone profile in at least one printing stand from a previous ink zone profile corresponding to a previous printing job to a subsequent ink zone profile corresponding to a subsequent printing job, the printing press comprising a printing plate cylinder for positioning a printing plate, an ink reservoir for holding a supply of ink and an inking mechanism for transferring the ink between the ink reservoir and the printing plate during operation of the printing stand, the inking mechanism comprising a plurality of inking rollers and a plurality of individually adjustable ink zone metering devices for transferring the ink between the ink reservoir and at least one of the plurality of inking rollers, the process comprising the steps of: (a) calculating at least one previous parameter characterizing the previous ink zone profile; (b) calculating at least one subsequent parameter characterizing the subsequent ink zone profile; and (c) adjusting at least one of the plurality of adjustable ink zone metering devices, in accordance with the calculated previous and the subsequent parameters, and operating the inking mechanism to thereby change the ink zone profile in the printing stand from the previous ink profile to the subsequent ink profile.
In one aspect, the process includes the steps of (A) beginning with the previous ink zone profile; (B) transferring ink from the inking mechanism, through at least one of the plurality of ink zone metering devices and into the ink reservoir so as to establish, on the plurality of inking rollers, a base ink layer, the base ink layer being substantially uniform in thickness across the ink zones; and (C) thereafter, transferring ink from the ink reservoir, through at least one of the plurality of ink zone metering devices and into the inking mechanism so as to establish the subsequent ink zone profile.
In another aspect, the process includes the steps of (A1) beginning with the previous ink zone profile; (B2) determining, for each of the plurality of ink zones, a volumetric difference indicator indicative of the change of ink volume between the ink volume remaining in the inking mechanism from the previous printing job and the ink volume required in the inking mechanism for the subsequent printing job; (C2) adjusting each of the plurality of ink metering devices in accordance with the corresponding ink zone volumetric difference indicator determined in step (B2): and (D2) actuating the inking mechanism until the subsequent ink zone profile is substantially achieved therein.
The invention will now be described by way of particular preferred embodiments, reference being had to the accompanying drawings, wherein:
US Referenced Citations (5)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 2073665 |
Oct 1981 |
GBX |
| 2080201 |
Feb 1982 |
GBX |
Continuations (1)
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Number |
Date |
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| Parent |
166556 |
Mar 1988 |
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Patent Grant
5010820
