REGISTER CONTROL SYSTEM
The present invention generally relates to remote control apparatus and particularly remote control apparatus for controlling cylinders that affect the reg- istration of printing done by a printing press or the like.
Offset printing presses as well as other types of printing presses have always utilized control systems of some type to- achieve proper registration of the printing that is done at locations that are longitu¬ dinally spaced from one another along the direction of the continuous web. While the early presses, and perhaps present inexpensive presses, employ only a manual control to move the critical controllable cylinder so as to laterally adjust the print location on the web as well as to circumferentially adjust the cylinder so as to either advance or retard the printing location along the web to obtain registration, there have been many improvements of the control of such cylinders over the years. Remote control systems which permit a pressman or operator to adjust the lateral and circumferential positions of the controllable cylinders have been available and systems currently exist which, have a number of controls for controlling the cylinders of a multi-color printing press, such as is shown on the master register control in FIG. 1 herein. The master control may be configured to have selector pushbuttons which select for control any one or more of five upper and lower controllable cylinders, although the precise number is not particularly relevant either to the prior art systems or to the present invention. Other push¬ buttons control the direction of lateral movement, i.e., toward the gear side or operator side In the axial direction for controlling the lateral registration of a cylinder, and advance and retard pushbuttons are pro-
vided for controlling the longitudinal registration. A ten digit keyboard together with stop and clear buttons can be used to key in the amount of movement that is to be accomplished by the system. A separate ZERO ALL CYLINDERS pushbutton can be depressed which will posi¬ tion all controllable cylinders of the press to return to their neutral or zero position. The master control preferably has a digital display which is adapted to provide a read-out of the amount of movement that will be carried out by the selected' cylinder. While the master control provides complete control over all cylinders of a-printing press, which in the illustration of FIG. 1 controls ten separate cylinders of a printing press, it requires manipulation by a pressman that is somewhat different from what he normally has experienced in many prior control systems. For example, if he wishes to make a slight adjustment of the lateral posi¬ tion of a cylinder which controls the red color, he must associate the proper selector switch to gain control of that cylinder and then key in the amount of movement that is desired and hit the appropriate direction push¬ button to accomplish the adjustment. There are there¬ fore three conscious steps, i.e., selection, amount and direction that are necessarily required to accomplish an adjustment in a particular direction for any one cylinder. The selection step also requires a pressman to make the association of which cylinder is to be con¬ trolled for adjustment of a particular color.
Accordingly, it is an object of the present invention to provide a control system which has all of the foregoing control capability, but which is more con¬ venient for a pressman or operator to use, taking into account his experience and habits.
Yet another object of the present invention is to provide a control system which has a master control of the foregoing type, but which also includes secondary
controls for each controllable cylinder, whereupon each secondary control is dedicated to a particular cylinder which enables easier association of the control with a particular cylinder. It is yet another object of the present inven¬ tion to provide a control system having dedicated cylinder secondary controls wherein the secondary con¬ trols include pushbuttons for determining the direction of adjusting movement, and wherein the secondary con- trols can be made to move a predetermined adjustment distance for each actuation of a direction control push¬ button switch. •
Still another object of the present invention is to provide a system of the foregoing type wherein the secondary control can be made to provide a predetermined rate of adjusting movement in response to continuous actuation of a particular directional pushbutton.
Still another object of the present invention is to provide a control system of the foregoing type wherein the dedicated secondary control includes a digital display which continuously displays either the lateral or circumferential cylinder position at all times.
Other objects and advantages will become apparent upon reading the following detailed descrip¬ tion, in conjunction with the attached drawings, in which:
FIGURE 1 is a plan view of the control console of the system embodying the present invention and par- ticularly illustrating the master control as well as two exemplary secondary controls;
FIG. 2 is an electrical schematic diagram of the electrical circuitry of the master control portion of the system; FIG. 3 is an electrical schematic diagram illustrating the electrical circuitry of two associate ^rn -r
secondary controls of the system;
FIG. 4 is an electrical schematic circuit dia¬ gram of circuitry that receives the analog positioning information and switching means for providing the appro- priate input to the analog-to-digital converter of the circuitry shown in FIG. 3; and,
FIG. 5 is an electrical schematic diagram of the circuitry which controls the operation of stepping motors for accomplishing the adjustment of the circu - ferential position of one of the controlled cylinders. Broadly stated, the present invention is directed to a control system for controlling the posi¬ tion of a controllable cylinder in a printing press or the like, such as the plate cylinders of an offset printing press, for example. The control system of the present invention is a microcomputer based closed loop feedback control system which positions the controllable cylinder laterally as well as circum erentially. The control of the position of the cylinders controls the ability to obtain and maintain registration of the various colors that are being printed on a continuous web. When an offset printing press is utilized for four color printing, there are upper and lower rolls for each of the four colors which require eight cylinders to be controlled to provide the proper registration during printing of the web.
The system includes a master control which has the capability of controlling each of the controllable cylinders by means of selector pushbuttons and control pushbuttons and the system also has secondary or slave controls which are dedicated to the control of respec¬ tive ones of the controllable cylinders. Since a press¬ man or operator may more easily make the mental associ¬ ation between a slave control panel and a particular cylinder that is controlled by that secondary control, the presence of the secondary control facilitates more f
efficient and easier control of the printing press during operation. This is true even though the master control panel can accomplish virtually the same control that may be provided by the secondary control panel. The secondary control also includes microcomputer based control circuitry which interfaces with the master con¬ trol panel circuitry. However, the secondary control provides different functional operations than is accom¬ plished by the master control, which results in more efficient and easier control of the printing press in many instances.
Turning now to the drawings, and particularly FIG. 1, the control panel o the system of the present invention is shown in FIG. 1 to comprise a leftward master control, indicated generally at 10, and number of secondary or slave controls, indicated generally at 12 and 14, shown to the right of the master control. The master control 10 has a number of upper cylinder selector switches 16 and lower cylinder selector switches 18, which when any one of them is actuated, selects those particular cylinders for control by other pushbuttons that are contained on the panel. A keyboard pad, indicated generally at 20, contains the ten numer¬ ical digits in addition to a CLEAR and a STOP push- button. The master control has lateral adjustment con¬ trol pushbuttons 22 and 24 which control the direction of the controlled cylinder along the axial direction of ■the cylinder, with pushbutton 22 causing the system to move the cylinder laterally toward the gear side and pushbutton 24 causes lateral movement toward the oper¬ ator side. Circumferential movement pushbuttons 26 and 28 move the cylinder so as to retard and advance, respectively, the circumferential position of the con¬ trollable cylinder so as to adjust the registration of the print in the longitudinal direction of the web so as to either advance or retard the position of the print ^^^~T _^~
OMPI
that is being performed by the cylinder being controlled.
Stated in other words, the advance or retard pushbuttons affect the rotational phase position of the cylinder being controlled so as to move the position of the printed material on the web either upstream or down¬ stream relative to the printing that is accomplished by the other cylinders of the printing press. A preferably liquid crystal digital display 30 is provided and this provides an indication of the position of the cylinder in either the circumferential or lateral modes, but both cannot be simultaneously indicated. All of the cylinders are provided with sensing means which will provide an indication of their lateral and circumfer¬ ential position and there is a home or zero position which is predetermined and from which the reading of the digital display 30 have a meaning. A ZERO ALL CYLINDERS pushbutton 32 is also provided, which when depressed, causes the system to place all cylinders at the zero position which is determined by the sensing means through closed loop feedback control.
During operation, if the operator wishes to move a cylinder, he enters the amount of the move on the keyboard 20 in thousandths of an inch and this amount will appear on the display 30. If he makes an error in entering the amount in the keyboard, he may press the CLEAR button and it will be cancelled. If the appro¬ priate amount Is entered, the pressman will then depress one of the direction buttons 22, 24, 26 or 28 depending upon the direction that he wishes the adjustment to be made and upon depressing of the appropriate pushbutton, and the adjustment will be commenced. As long as the move is being actively carried out, the appropriate button of a secondary control panel will be lighted, and upon completion of the move, that light will he extin- guished. The move will be carried out on any selected cylinder that is determined by the selector pushbuttons
OMPI
16 or 18. Thus, if any one or more of the pushbuttons 16 or 18 is actuated, it will be lighted and the appro¬ priate move that was keyed into the keyboard 20 and initiated by one of the direction pushbuttons will be carried out in all selected cylinders. If, during move¬ ment in the chosen direction, the pressman determines that the directed move should not be made, he may abort the move at any time by depressing the STOP pushbutton of the keyboard 20. This will immediately terminate any move in progress.
In accordance with an important aspect of the present invention, the secondary controls 12 and 14 are provided, preferably adjacent the master control 10 and a secondary control is provided for each cylinder and is thereby dedicated to a particular cylinder. If the system contains ten separate controllable cylinders as implied by the ten pushbuttons 16 and 18 of the master control, then there will be ten separate secondary con¬ trols, comparable to the controls 12 or 14. Since a particular printing station or tower is generally adapted to print the same color, the upper and lower cylinder for any particular station or tower is prefer¬ ably provided with a pair of secondary controls that are color coded by some means so that the operator immedi- ately knows the color associated with that station. Since all secondary controls are substantially iden¬ tical, only one of them will be described in detail.
The station 12 has direction pushbuttons 22', 24', 26' and 28' that operate in the same manner as the correspondingly numbered pushbutton of the master con¬ trol and a digital display 30' is also provided. The panel also has a pair of pushbuttons 34 and 36 having integral indicator lights which are labeled circumfer¬ ential and lateral, respectively, and when the appro- priate one is lighted, the display 30' illustrates the position of the cylinder relative to its zero position.
OMPI
in the particular direction. Thus, when the display illustrates a lateral mode, a ,,+" indicating sign in the display 30' indicates the cylinder position is toward the gear side of the mechanical zero by the indicated amount and a "-" display indicates the cylinder position is toward the operator side of the mechanical zero. Similarly, in the circumferential mode, a "+" display indicates the cylinder position is advanced from mechan¬ ical zero and a "-" display indicates that the cylinder position is retarded from mechanical zero by the indi¬ cated amount. If the circumferential position is shown and it is desired to have the lateral position dis¬ played, then the lateral pushbutton 36 may be depressed and it will become lighted and the display will appro— priately indicate the lateral position.
Actuation of any one of the four directional pushbuttons causes the system to operate in a manner that is somewhat different from that of the master con¬ trol. As previously indicated, the operator using the master control must key in the amount of movement in thousandths on the keyboard 20 before implementing the directional pushbutton. In the secondary control 12, it can be set up to automatically move the cylinder in the chosen direction by a predetermined amount that is determined by switches that will be described in con¬ nection with the schematic circuit diagram of FIG. 2. While it is a function of the software control in that circuitry, the settable switches enable the system to cause movements In predetermined amounts such as one, two, or three-thousandths of an inch upon depressing of any one of the pushbuttons 22'-28' so that everyti e the operator depresses a directional pushbutton, the system will cause the cylinder to be moved by the predetermined amount. The system is also adapted to be set so that it will move the cylinder in the chosen direction as deter¬ mined by depression of the appropriate pushbutton
22'-28' at a predetermined rate of movement, e.g., two-thousandths of an inch per second and this move will be accomplished as long as the pushbutton is depressed by an operator. Regardless of whether the system is configured for continuous movement or predetermined increments of movement during operation, the system will have the pushbutton lighted during the course of its movement and it will be extinguished upon completion of the movement. Turning now to the detailed circuitry which carries out the operation of the system that has been described with respect to the control panels shown in FIG. 1, FIG. 2 illustrates much of the circuitry for the _ master control 10 which interfaces with the secondary controls such as the secondary controls 12 and 14 of
FIG. 1, the detailed circuitry of which is shown in FIG. 3. The broad general operation of the circuitry is that the master control contains a microcomputer which inter¬ faces with the display and pushbutton circuitry of the master control as well as with the indicator lights thereof. The circuitry also has a data bus that extends to each of the secondary controls. The secondary con¬ trols also contain microcomputer which in turn interface with the secondary control pushbuttons, indicator lights and display, in addition to the cylinder position sensors which supply feedback information that provides closed loop servo control of the motors which position the cylinders. Communication between the master control circuitry and the secondary control circuitry is accom- plished by interrupts being generated by the micro¬ computer of the master control in response to commands being generated by an operator. An interrupt line interconnects the circuitry of FIG. 2 with each of the secondary controls as will be hereinafter discussed. Referring .again to FIG. 2, a microcomputer 40, which is preferably an Intel No. 8741 8-bit microcomputer,
eight data bus lines 42, a read control line 44, and write control line 46 which provide the proper control signals to exchange information through tri-state devices that will be hereinafter described. The micro- computer 40 has eight output port lines 48 which extend to a liquid crystal display driver, such as a Hughes No. HLCD0437 that in turn drives a liquid crystal display such as a Hamlin No. 3937. Since these devices are con¬ ventional and their interconnection is standard and straightforward, they have not been shown in detail, except as illustrated in FIG. 1. The control lines 48 include four lines of binary coded decimal information and four control lines for selecting the appropriate one of four digit locations. The microcomputer 40 also includes additional port lines 50 which extend to a pair of peripheral devices 52 and 54 which function to pro¬ vide additional ports to the microcomputer 40. The peripheral devices are programmable and a program line 56 controls this operation. The interface 52 is selected for operation by a chip select port line 58 and the peripheral interface 54 is selected by activation of the chip select port line 60 from the microcomputer. The peripheral interface 52 has four output ports 62 which extend to four columns of a switching matrix and ports 64 are input ports from eight separate rows of the matrix. The depression of any one pushbutton will be detected as a matrix intersection at a specific location which enables the system to determine which pushbutton has been depressed. The matrix for the switch buttons is not shown in detail and is a conventional 4 column by 8 row switch matrix. The interface also has three address lines 66 which extend to a 3 x 8 address decoder 68 and a final port line 70 extends to a tri-state buffer 72 as well as to an inverter 74 for driving the light in the ZERO ALL CYLINDERS pushbutton 32 located on the master control. The peripheral interface 54
number of output lines 76 which extend to respective driver chips 78 and 80 having output lines 82 and 84, respectively, for lighting the selector pushbuttons 16 and 18 as well as the directional pushbuttons 22, 24, 26 and 28.
When the microcomputer 40 wishes to communicate with one of the secondary controls, it commands the peripheral interface 52 to activate the address lines 66 so as to cause the decoder 68 to activate one of the six output lines 86 which extend to a line driver 88 and this device places the appropriate interrupt line 90 active. The lines 90 extend to the circuitry of the secondary controls as will be discussed. When one of the lines 90 is active, then a gate 92 is also acti- vated. The output of gate 92 appears on line 93 which activates a tri-state input/output line driver or data buffer 94 for communicating with the particular secon¬ dary control that the interrupt has been sent to. The write line 46 then controls the data buffer 94 to either send or receive data on the data bus 96 that extends to the secondary control panels. From the foregoing description, it should be appreciated that the micro¬ computer can utilize the peripheral interface 52 through the decoder 68 and line driver 88 to provide interrupts to the secondary controls. The microcomputer 40 can also use the peripheral interface 52 and the same address lines 66 and 70 to obtain information from the tri-state buffer 72 when its control line 100 is active. The control line 100 is controlled by a line 102 via an inverter 104. The tri-state buffer 72 has a pair of output lines 106 and another pair 108 which are connected to sources of positive voltage and have switches 110 which can be preset to determine the appro¬ priate limits for operation of the system as has been previously described. More particularly, the lines 106 provide digital levels which provide the absolute limits
of movement for the cylinders and depending upon the positioning of the two switches, these lines can control the maximum movement within the ranges of either plus or minus 120, 125, 130 or 135-thouεandths of an inch. Similarly, the lines 108 can be set by the switches to have levels for controlling the amount of movement that is to be accomplished by actuation of the directional pushbuttons 22', 24', 26' and 28' of the secondary con¬ trols. These are set to provide minimum movements of either 1, 2 or 3- housandths of an inch for each actu¬ ation of the switch or when the switches are in the fourth possible decoded position, to cause the cylinders final destination to be changed at a rate of 2-thousandths of an inch per second, with the change being continuously carried out as long as one of the pushbuttons is maintained in an actuating state. Read/write control lines 116 and 118 are actually input lines to the line driver 88 and these control lines originate in the microcomputer of the secondary control. Turning now to the specific circuitry for the secondary controls shown in FIG. 3, it also includes a microcomputer 140 having data bus lines 142 that are connected to a tri-state bidirectional driver 144 having output lines 96 which are connected to the master con- trol bus lines as well as to other of the secondary con¬ trols. The microcomputer 140 has a read control line 146 that is connected through driver 148 to the line 116 and a write command line 150 that extends to the tri-state driver 144 as well as through a driver 151 to line 118. The microcomputer 140 has four lines 152 which extend to each of three peripheral interface cir¬ cuits 154, 156 and 158 for expanding the port capability of the microcomputer in the manner as previously described with respect to the master control circuitry and these peripheral interface circuits are selected when their chip select lines 160, 162 and 164,
tively, are active. These interface circuits are pro¬ grammable and a program control line 166 extends from the microcomputer 140 to each of them.
As previously mentioned, the system of the present invention utilizes a linear variable differ¬ ential transformer as a sensing device and it generates an analog signal as the core moves in the transformer to change the coupling between the primary and secondary windings. The analog level from a selected transformer is applied to line 170 that is the input to an analog-to- digital converter 172. The analog-to-digital converter is an Analog Devices Model AD 571K which is connected to operate as a 10-bit resolution successive approximation analog-to-digital converter in a bipolar mode. The out- put of the converter appears on lines 174, eight of which extend directly to ports of the microcomputer 140 with the first and second most significant bits being connected to two ports of the peripheral interface 154. A line 176 from the microcomputer 140 activates the analog-to-digital converter to begin converting and once the conversion has been completed, it provides an active signal on line 178 which extends to the microcomputer 140. It should be appreciated, however, that the micro¬ computer may be performing other operations which pre- vent it from looking at the converter for a predeter¬ mined amount of time. If the time is in excess of the specified conversion time of the converter, the correct data will be available on the lines 174 when the micro¬ computer is ready to read the data. Therefore the data ready signal on line 178 may be unnecessary if the circuitry operates in this manner.
The peripheral interface 154 has output lines 180 which extend to and are connected to a liquid crystal display driver and liquid crystal display (not shown) which are similar to those described with respect to the master control circuitry. The peripheral in er^<** *g_£
face 156 has seven lines 182 which extend to a three by four keyboard matrix of the secondary control panel. A port line 184 extends to the tri-state driver 144 and controls the operation of the tri-state bidirectional driver to enable it to transmit data on the data bus 96. The peripheral interface 158 has port lines 186 which extend to and control driver circuits 188 and 190 which have respective output lines 192 and 194 which control the light emitting diodes in the pushbuttons of the secondary control and also connect the operation of the control circuitry for actuating the synchronous stepping motors that move the cylinder to perform the necessary adjustment. The peripheral interface 158 also has four output port lines 196 which extend to a selector circuit 198 (see FIG. 4) which selects one of four analog inputs from the linear variable differential transformers that are associated with the cylinders. It should be understood that each stage or tower of the printing press has an upper and lower cylinder which is controlled and the circuitry of FIG. 3 is adapted to control both cylinders. Since each cylinder has an. axially oriented differential transformer as well as a differential transformer oriented to measure circumfer¬ ential position, there are a total of four such trans- formers for the two cylinders. The peripheral interface 158 enables the microcomputer 140 to address the switch¬ ing circuit 198 to provide the selected analog input on line 170 to the analog-to-digital converter.
More specifically and referring to FIG. 4, the switching circuit 198 is shown to have an input line 200 which extends to associated circuitry which effectively adjusts the range of the analog signal to accommodate the output of the differential transformer itself which is applied on input line 202. In addition to the input 200 from the illustrated circuitry, the three other input lines 204 are shown and can be selected by
appropriate levels on the lines 196. The selected input has its analog value appearing on the output line 206 which is filtered by filter 208 and buffered by a buffer 210 and provides the analog signal on output line 170 that is applied to the circuitry of FIG. 2.
To drive the motors in one of opposite direc¬ tions, drive circuitry shown in PIG. 5 is provided so that one of the various control lines 192 can cause the motor to be driven a desired direction. Since each tower or station has four motors, i.e., a motor for con¬ trolling the lateral position of each of the two cylinders, as well as a motor for controlling the cir¬ cumferential position of each of the cylinders, there will be additional circuitry included that is not shown in FIG. 5. More particularly, the circuitry shown to the left of the dotted line will be multiplied four times, inasmuch as the circuitry shown is for a single motor. The motor control circuitry will be enabled upon activation of an appropriate control signal on one of the lines 192. Assuming the leftmost lines 192 are energized, then light emitting diode 226 will be acti¬ vated which will place photo-transistor 228 into conduc¬ tion and will cause the driver 230 to provide gate cur¬ rent to a gate 232 of a triac 234 which will be placed into conduction and which will cause motor current to be sent through coil 236 for driving the motor in the direction so as to advance the circumferential position of the controlled cylinder. A similar circuit can be activated by energization of the other illustrated line 192 which will result in the light emitting diode 240 placing photo-transistor 242 into conduction which will result in gate current being applied to gate 244 which will turn on a triac 246 and provide current to the coil 238 which will drive the motor in the opposite direc- tion. An RC phase shift network, indicated generally at
240, causes the motor voltage In the coil opposite the
coil being directly driven by the conducting triac to lag that of the other and thereby produce rotation in the appropriate desired direction.
From the foregoing, it should be appreciated that an improved remote control system has been shown and described which is particularly adapted for use in controlling the positioning of a controllable cylinder such as is used in a printing press or the like. One significant advantage lies in the fact that the system has a master control which can effectively control any one of the cylinders and also includes secondary con¬ trols which are dedicated to particular cylinders and which provides the pressman or operator with an easy direct association with the cylinder that is being con- trolled. All the pressman needs to do to make an adjustment is to depress a pushbutton providing correc¬ tion in one of the four directions and by virtue of being capable of being preset, results in an adjustment of a predetermined amount. Alternately, if the pressman prefers to have the target cylinder location change at a predetermined rate of speed,, such can be set so that the appropriate pushbutton will result in continued change until the pushbutton is released.
Although particular embodiments of the present invention have been illustrated and described, various modifications, substitutions and alternatives will be apparent to those skilled in the art and, accordingly, the scope of the present invention should only be defined by the appended claims and equivalents thereof. Various features of the invention are set forth in the following claims.
SUBSTITUTE S