Patent Application
20080229945
The invention relates generally to dampening spray systems in offset printing processes and, more specifically, to spray dampening valves in the dampening spray systems.
In the offset printing process, a small amount of a dampening solution, i.e., water with certain additives, is supplied to the offset plate, which then comes in contact with the inking rollers, the ink adhering to the image on the plate and the dampening solution adhering to the other portions of the plate. The quantity and placement of the dampening solution must be varied for different types and densities of ink, variations in printing densities and ink coverage, and press speed. Control of the application of the dampening fluid is particularly important in four-color process, where variations will affect color. If too little fluid is applied, printing will occur in areas where none is desired. If too much fluid is applied, printing may not occur in some areas, or image density may drop.
Various systems for dampening the plate cylinder of an offset printing apparatus are in use today. One such system employs dampening rollers which rotate partially within an open trough containing dampening fluid. The dampening rollers bear directly or indirectly against the plate cylinder, thereby supplying a film of dampening fluid to the plate cylinder. This system, however, suffers from a number of inherent disadvantages from the standpoint of both operation and maintenance. From the operational standpoint, the system is too imprecise and difficult to control. Frequently, too much or too little solution is applied to the plate roller, or at least to certain areas of the plate roller, reducing the printing quality.
Another known dampening system eliminates the open fluid container and the immersed dampening roll, and replaces them with a closed system which pumps dampening fluid as a spray onto a dampening roll train for application to the plate cylinder. In such a spray dampening system, the dampening fluid is sprayed onto the press rollers by means of a linear array of spray nozzles with the spray patterns of the individual nozzles merging to form a continuous composite spray pattern across the surface of the press roller. It is important in obtaining proper dampening that the distribution of dampening fluid be as uniform as possible. There should be no starved areas where the amount of dampening fluid is substantially less than the other areas on the surface of the roller, and the overlapping of the adjacent individual spray patterns should be minimized so that there is little or no excessive dampening fluid applied to any portion of the dampening roller.
Various attempts have been made at adjusting the amount of dampening fluid applied to the dampening roll. In known dampening systems nozzles fluctuate between open and closed positions to regulate the amount of dampening fluid applied to the rolls, nozzles are pulsed on and off with the pulse width and/or frequency being adjusted, dampening fluid is delivered through alternate laterally adjacent nozzles, etc. However, none of the known systems provide for the accuracy and repeatability that is desired for this application.
In approximately 1998, Baldwin/Jimek introduced a means of adjusting the stroke-length of each valve. Each valve had a threaded adjustable stop, and a jam-nut. This allowed the operator to adjust flow-rate for given conditions. Association between this mechanical compensation and the spraybar was accomplished in this system. However, it is not purely electronic.
In approximately 1996, Smith RPM Corporation provided a means of manually creating corrections to equalize the flow-rate of each valve. These corrections were stored in the spraybar controller. As such, the corrections were associated with the location within the system not the spraybar. When a new spraybar is installed, the calibration procedure must be repeated. Our embodiments differ in that they are automated, and associated with the spraybar, not the location in the system.
In approximately 1999 the press control company EAE (Ewert Ahrensburg Electronik GmBH) introduced a system they called “PRINT4”. This system had a provision where final running values (as adjusted by the operator) of all devices were stored and compared to initial (anticipated) set points. After a number of iterations, the system could “learn” the variations, and compensate for them. The “feedback” in PRINT4 is human intervention, which differs greatly from our genuine measured feedback. The “PRINT4” concept associates corrections with location within the system, not the corrected devices.
Therefore, there is a need in the art for an improved and more accurate spray dampening devices for use in the offset printing process. That is, in spray dampening, there has long been a need to establish an absolute volumetric valve output, which is associated with some applied system setpoint “X”. Such that, when setpoint “X” is applied to any spraybar valve, the output is predictable and equal for every spraybar in the dampening system.
One embodiment of the present method and apparatus encompasses an apparatus. In this embodiment the apparatus may comprise: a spraybar assembly having a plurality of spray valves; a unique identification associated with the spraybar assembly; response profile having a plurality of characteristic profiles, characteristic profiles of the plurality of characteristic profiles correspondingly respectively to spray valves of the plurality of spray valves; and the response profile being associated with the spraybar assembly.
Another embodiment of the present method and apparatus encompasses a method. This embodiment of the method may comprise: connecting a spraybar assembly having a plurality of valves to a test/calibration apparatus, and monitoring at least one predetermined parameter of each valve of the plurality of valves; operating the plurality of valves of the spraybar assembly by the test/calibration apparatus at predetermined operating parameters while monitoring dynamic characteristics of the plurality of valves; generating via the test/calibration apparatus a respective characteristic profile for each respective valve of the plurality of valves; and storing the characteristic profiles as a response profile of the spraybar assembly in a non-volatile memory on the spraybar assembly.
Features of the embodiments will become apparent from the description, the claims, and the accompanying drawings in which:
In the offset printing process, a small amount of a dampening solution, for example water with certain additives, is sprayed onto the offset plate by a plurality of solenoid valves.
In spray dampening, embodiments of the present method and apparatus encompass a spraybar wherein an absolute volumetric valve output is established, which is associated with some applied system setpoint “X”. Such that, when setpoint “X” is applied to any spraybar valve, the output is predictable and equal for every spraybar in the dampening system.
Embodiments of the present method and apparatus encompass an electronic feedback. By employing an electronic sensor(s) in the process, the valve response may be monitored to defined operating parameters significant parameters electronically. This feedback permits imparting varying degrees of automation, in correcting the output of valves demonstrating output variation.
Embodiments of the present method and apparatus also encompass unique associatively. The delivery device (spraybar) in a spray dampening system is a highly portable device. Typically the spraybar will migrate frequently, independently of the control electronics. Correction data/adjustments are unique for every spraybar. It is imperative that any correction data/adjustment move with the spraybar, or be transferred to the spraybar in a manner that maintains this unique relationship.
While different printing operations may require fewer or more rollers than shown in
The spray dampening control system, generally designated 15, includes one or more solenoid-operated spray nozzle bars, one shown as reference character 16. In the printing operation, spray bar 16 may include, for example, four solenoid-operated spray nozzles 18a, 18b, 18c, 18d, spaced apart from each other and from the inking roller 12, such that the spray jet emitted from the nozzles uniformly covers the surface of such roller. For the sake of clarity the inking system for applying the oil base ink to the inking roller 12 is not shown.
Each solenoid controlled spray nozzle may have an input plumbed to a liquid supply line 20. The electrically controlled nozzles may be, for example, of a normally off type where the application of an electrical signal opens the nozzle valve to allow the pressurized liquid to be sprayed for the duration of the signal. Ideally electrically controlled nozzles of this type, being either fully on or off, provide a constant angle of spray when activated and thus maintain a constant area of coverage even though the volume of liquid sprayed may be reduced. With this arrangement the volume of liquid sprayed is increased either with an increase in frequency, or by an increase in the duration of the electrical signal. A main liquid supply conduit 22 provides spray dampening fluid at a pressure of about 40-90 pounds to the supply lines 20 through respective shut off valves 24 and filters 26.
Each valve position will be excited under known conditions. The system will electronically evaluate the valve response using a calibration apparatus, which is located off of the press. Then correction factors will be established to equalize the outputs. The system may include the capability of monitoring all influential parameters, such as temperature, pressure, etc. . . . Once the set of correction data is established, it will be uniquely associated with its corresponding spraybar through one of the following (but not limited to) methods. These are listed in order of sophistication.
The spraybar assembly 302 may have a plurality of valves 303. It is to be understood that the embodiments of the present method and apparatus may utilize valves with or without attached nozzles.
After completion of the calibration phase, the spraybar assembly 302 may be moved from the calibration location 308 to a printing press location 314. The spraybar identifier, for example, the serial number 304, and associated correction data for the spraybar 302 may be manually entered into central control system, for example CCS database 310, by a user 307. A system, such as a printing apparatus, may have many spraybar assemblies. The location of each spraybar in the system may be entered manually into the CCS database 310. In operation, the central control system may deliver respective corrections to a local spraybar controller 312 operating the spraybar 302.
The sequence of events are:
A. Operator 307 visually locates serial number 304 on spraybar assembly 302 and enters it at the CALIBRATION UNIT 306.
B. CALIBRATION UNIT 306 excites spraybar valves 303, analyzes valve response, and generates correction data.
C. Operator 307 reads back serial number 304 and corresponding correction data.
D. Operator 307 enters serial number 304, corresponding correction data, and location within system into CENTRAL CONTROL SYSTEM/DATABASE 310.
E. CENTRAL CONTROL SYSTEM/DATABASE 310 downloads correction data to SPRAYBAR CONTROLLER 312 at printing press location 314.
F. During operation, SPRAYBAR CONTROLLER 312 applies modified electrical signals to the nozzles 303 of the spraybar assembly 302 based on the corresponding correction data.
As previously described, the spraybar assembly 402 may have a plurality of valves 403. At a calibration location 408 the calibration unit 406 is operatively coupled to the spraybar assembly 402 having a serial number 404. The CENTRAL CONTROL SYSTEM/DATABASE 410 may be operatively coupled to a respective spraybar controller 412 that operates the spraybar 402 in the printing press location 414.
The sequence of events is:
A. Operator 407 visually locates serial number 404 on spraybar assembly 402 and enters it at the CALIBRATION UNIT 406.
B. CALIBRATION UNIT 406 excites spraybar valves 403, analyzes valve response, and generates correction data.
C. CALIBRATION UNIT 406 transfers spraybar serial number 404 and corresponding correction data to CENTRAL CONTROL SYSTEM/DATABASE 410 via a data link.
D. Operator 407 enters printing press location 414 of the spraybar assembly 402 within system into the CENTRAL CONTROL SYSTEM/DATABASE 410.
E. CENTRAL CONTROL SYSTEM/DATABASE 410 downloads correction data to SPRAYBAR CONTROLLER 412 at printing press location 414.
F. During operation, SPRAYBAR CONTROLLER 412 applies modified electrical signals to the nozzles 403 of the spraybar assembly 402 based on the corresponding correction data.
As previously described, the spraybar assembly 502 may have a plurality of valves 503. At a calibration location 508 the calibration unit 506 is operatively coupled to the spraybar assembly 502 having an electronic identifier 504. The CENTRAL CONTROL SYSTEM/DATABASE 510 may be operatively coupled to a respective spraybar controller 512 that operates the spraybar 502 in the printing press location 514.
The sequence of events is:
A. CALIBRATION UNIT 506 reads ELECTRONIC IDENTIFIER 504 aboard spraybar assembly 502.
B. CALIBRATION UNIT 506 excites spraybar valves 503, analyzes valve response, and generates correction data.
C. CALIBRATION UNIT 506 transfers spraybar identification from the electronic identifier 504 and corresponding correction data to CENTRAL CONTROL SYSTEM/DATABASE 510 via a data link.
D. Operator 507 enters printing press location 514 of the spraybar assembly 502 within system into CENTRAL CONTROL SYSTEM/DATABASE 510.
E. CENTRAL CONTROL SYSTEM/DATABASE 510 downloads correction data to SPRAYBAR CONTROLLER 512 at printing press location 514.
F. During operation, SPRAYBAR CONTROLLER 512 applies modified electrical signals to the nozzles 503 of the spraybar assembly 502 based on the corresponding correction data.
As previously described, the spraybar assembly 602 may have a plurality of valves 603. At a calibration location 608 the calibration unit 606 is operatively coupled to the spraybar assembly 602 having an electronic identifier 604. The CENTRAL CONTROL SYSTEM/DATABASE 610 may be operatively coupled to a respective spraybar controller 612 that operates the spraybar 602 in the printing press location 614.
The sequence of events is:
A. CALIBRATION UNIT 606 reads ELECTRONIC IDENTIFIER 604 aboard spraybar assembly 602.
B. CALIBRATION UNIT 606 excites spraybar valves 603, analyzes valve response, and generates correction data.
C. CALIBRATION UNIT 606 transfers spraybar identification from the electronic identifier 604 and corresponding correction data to CENTRAL CONTROL SYSTEM/DATABASE 610 via a data link.
D. SPRAYBAR CONTROLLER 612 reads ELECTRONIC IDENTIFIER 604 aboard spraybar assembly 602.
E. CENTRAL CONTROL SYSTEM/DATABASE 610 receives spraybar identification from SPRAYBAR CONTROLLER 612.
F. CENTRAL CONTROL SYSTEM/DATABASE 610 downloads correction data to SPRAYBAR CONTROLLER 612 at printing press location 614.
G. During operation, SPRAYBAR CONTROLLER applies modified electrical signals to the nozzles 603 of the spraybar assembly 602 based on the corresponding correction data.
As previously described, the spraybar assembly 702 may have a plurality of valves 703. At a calibration location 708 the calibration unit 706 is operatively coupled to the spraybar assembly 702 having a non-volatile memory 704. A respective spraybar controller 712 operates the spraybar assembly 702 in the printing press location 714.
The sequence of events is:
A. CALIBRATION UNIT 706 excites spraybar valves 703, analyzes valve response, and generates correction data.
B. CALIBRATION UNIT 706 transfers correction data to ONBOARD MEMORY 704 on spraybar assembly 702.
C. SPRAYBAR CONTROLLER 712 reads ONBOARD MEMORY 704 uploading spraybar identification and correction data.
D. During operation, SPRAYBAR CONTROLLER 712 applies modified electrical signals to the nozzles 703 of the spraybar assembly 702 based on the corresponding correction data.
As previously described, the spraybar assembly 806 may have a plurality of valves 803. A respective spraybar controller 804 operates the spraybar assembly 802 in the printing press location 810. Distributed instrumentation 802 is operatively coupled to the spraybar controller 804 and to the spraybar assembly 806.
The sequence of events is:
A. SPRAYBAR CONTROLLER 806 excites spraybar valves 803.
B. DISTRIBUTED INSTRUMENTATION 802 senses response to excitation.
C. DISTRIBUTED INSTRUMENTATION 802 delivers feedback to SPRAYBAR CONTROLLER 804.
D. SPRAYBAR CONTROLLER 804 generates correction data based on received feedback, and during operation, SPRAYBAR CONTROLLER 804 applies modified electrical signals to the nozzles 803 of the spraybar assembly 802 based on the corresponding correction data.
Spraybar assembly is connected to test/calibration apparatus, where critical parameters are monitored (step 1001).
Calibration apparatus performs self-test to verify functionality of all instrumentation (step 1002).
The test/calibration apparatus cycles one or more valves at defined operating parameters while monitoring the dynamic characteristics via instrumentation (step 1003).
If the initial characteristics are judged as being outside of an acceptable range, the valve is identified as faulty and in need of service (step 1004).
If the valve is within an acceptable range, the test/calibration apparatus proceeds to vary the applied electrical pulse-width, creating a characteristic profile based on the valves response. Although this embodiment varies the applied electrical pulse-width, several parameters, such as frequency or pressure could also be used to develop a response profile. Alternately, the test/calibration apparatus may modify the operating parameters until the valve's response is equal to a predetermined standard for the existing conditions (pressure, temperature, etc. . . . ) (step 1005).
A characteristic profile is then stored for a first valve (step 1006).
The test/calibration apparatus proceeds sequentially to automatically generate characteristic profiles for all the valves in the spraybar assembly, the characteristic profiles forming a response profile of the spraybar assembly (step 1007).
The test/calibration apparatus generates correction data based on the established characteristic profiles (step 1008).
The test/calibration apparatus applies the correction data to each valve to verify successful compensation (step 1009).
Once successful compensation is verified, the test/calibration apparatus writes all the characteristic profiles to a non-volatile memory residing on the spraybar assembly (step 1010).
If necessary, the spraybar assembly may be recalibrated (step 1011).
Each spraybar assembly is connected to a respective spraybar controller (step 1101).
The respective spraybar controller reads the characteristic profiles in the response profile from the non-volatile memory in the respective spraybar assembly (step 1102).
The respective spraybar controller uses characteristic profiles to calculate correction data unique to the respective spraybar assembly based on currently chosen running conditions (step 1103).
The respective spraybar controller applies the correction data such that equal user settings generate equal valve outputs (step 1104).
The present method and apparatus may be incorporated in a many other embodiments than just those depicted in this disclosure. For example, the spraybar controller may be internal to the spraybar assembly. In such embodiments, the spraybar controller remains with the spraybar assembly when it is moved from one location to another.
The steps or operations described herein are just some examples of the present method and apparatus. There may be many variations to these steps or operations without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted, or modified.
Although embodiments of the present method and apparatus have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the following claims.
