BACKGROUND OF THE INVENTION
[0001] The present invention relates to offset printing presses and, particularly, to the
electronic control of such presses.
[0002] Web offset printing presses have gained widespread acceptance by metropolitan daily
as well as weekly newspapers. Such presses produce a quality black and white or colour
product at very high speeds. To maintain image quality, a number of printing functions
must be controlled very precisely as the press is operating. These include the control
of press speed, the control of color register, the control of ink flow and the control
of dampening water.
[0003] In all printing processes there must be some way to separate the image area from
the non-image area. This is done in letterpress printing by raising the image area
above the non-image area and is termed "relief printing". The ink roller only touches
the high part of the plate, which in turn, touches the paper to transfer the ink.
In offset lithography, however, the separation is achieved chemically. The lithographic
plate has a flat surface and the image area is made grease-receptive so that it will
accept ink, and the non-image area is made water-receptive so it will repel ink when
wet.
[0004] In a web offset printing press the lithographic plate is mounted to a rotating plate
cylinder. The ink is injected onto an ink pickup roller and from there it is conveyed
through a series of transfer rollers which spread the ink uniformly along their length
and transfer the ink to the image areas of the rotating plate. Similarly, dampening
water is applied to a fountain roller and is conveyed through one or more transfer
rollers to the non-image areas of the rotating plate cylinder. The plate cylinder
rotates in contact with a blanket cylinder which transfers the ink image from the
plate cylinder to the moving paper web.
[0005] It is readily apparent that the amount of ink and dampening water supplied to the
plate cylinder is directly proportional to the press speed. At higher press speeds
the plate cylinder and blanket cylinder transfer ink and water to the paper web at
a higher rate, and the inking and dampening systems must, therefore, supply more ink
and water. It is also well known that this relationship is not linear and that the
rate at which ink and dampening water is applied follows a complex rate curve which
is unique to each press and may be unique to reach run on a press. Not so apparent
is the fact that the ink and water may be applied non-uniformly across the width of
the ink pickup roller and the fountain roller in order to achieve uniform printing
quality along the width of the web. If this is not done, there may be significant
changes in the quality of the printed images across the width of the moving web.
[0006] Prior press control systems have provided limited control over the rate at which
dampening water and ink has been applied as a function of press speed. For example,
in the case of damping water, these systems pulse the nozzles on the spray bar on
and off at one of a plurality of selectable pulse rates. The particular pulse rate
selected is determined by the press speed. The particular pulse rates and selection
points between pulse rates is preset to follow the dampening rate curve of the press
as closely as possible. There is no means for easily changing these values or for
providing a continuous range of pulse rates which closely follow the rate curve. In
addition, while the amount of dampening water applied by the spray bar can be adjusted
over the width thereof, this is a manual adjustment which may only be made locally
at a spray bar controller. Thus, if inconsistencies in print quality are observed
over the width of the image, manual adjustments to the circuitry must be made at a
local control panel.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a control system for an offset printing press and,
particularly, to the control of a dampening system and ink system on such a press.
[0008] The present invention includes a communications link with the press control system
that enables parameters, such as dampening rate curve data and ink rate curve data
to be downloaded and acted upon.
[0009] A control system of the present invention is for operating at least one set of nozzles
on a spray bar and at least one set of plungers on an ink injection device for the
printing press. The control system has the following components:
memory means for storing at least damp rate curve data and ink rate curve data which
is utilized to control operation the nozzles and plungers, respectively;
means for processing connected to the memory bans the means for processing providing
a damp rate control signal as a function of the damp rate curve data and providing
an ink rate control signal as a function of the ink rate curve data;
first interface means for connecting the set of nozzles to the means for processing
and being responsive to the damp rate control signal to control operation of the nozzles;
second interface means for connecting the set of plungers to the means for processing
and being responsive to the ink rate control signal to control operation of the plungers;
means for communicating connected to at least said memory means and being operable
in response to a received rate curve message to alter the damp rate curve data and
the ink rate curve data stored in the memory means, each of the damp rate and ink
rate curve data including a plurality of points, and wherein each point in the damp
rate and ink rate curve data indicates the amount of damping solution and ink required
at a specific press speed, the ink rate curve data having a primary ink rate curve
composed of a plurality of data points connected together by interpolation of the
data points and first and second secondary ink rate curves which are displaced from
the primary ink rate curve by positive and negative factors, respectively, said positive
and negative factors being a predetermined percentage of a greatest point of data
of said plurality of data points of the primary ink rate curve the points indicating
the amount of ink required at a specific press speed.
[0010] In a preferred embodiment, the predetermined percentage is 20% (see FIG. 13). The
plurality of data points is ten data points and are connected together by straight
line segments The damp rate curve data has a damp rate curve (see FIG. 12) composed
of a plurality of data points connected together by an interpolation of the data points,
the data points indicating the amount of damping water required at a specific press
speed. The plurality of data points is ten data points and are connected together
by straight line segments. The memory means stores a plurality of different ink rate
curve data and a plurality of different damp rate curve data as a function of paper
type, ink type and damping solution used in the printing press. The means for communicating
is connected to a master work station and the master work station stores a plurality
of different ink rate curve data and a plurality of different damp rate curve data
as a function of paper type, ink type and damping solution used in the printing press.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The features of the present invention which are believed to be novel, are set forth
with particularity in the appended claims. The invention, together with further objects
and advantages, may best be understood by reference to the following description taken
in conjunction with the accompanying drawings, in the several Figures in which like
reference numerals identify like elements, and in which:
FIG. 1 is a schematic representation of a web offset printing press and its control
system;
FIG. 2 is a schematic representation of two printing units in the press of FIG. 1;
FIG. 3 is a pictorial view of a dampening water spray bar which is employed in the
printing units of FIG. 2;
FIG. 4 is an electrical block diagram of a unit controller which forms part of the
press control system of FIG. 1;
FIG. 5 is an electrical schematic diagram of a dampener, register, ink ("drink") processor
which forms part of the unit controller of FIG. 4;
FIG. 6 is an electrical schematic diagram of a solenoid interface circuit which forms
part of the drink processor of FIG. 5;
FIG. 7 is an electrical schematic diagram of a speed interface circuit which forms
part of the drink processor of FIG. 5;
FIG. 8 is a schematic representation of important data structures which are stored
in the RAM of FIG. 5;
FIGS. 9A-9C are schematic representations of specific data structures which are shown
as blocks in FIG. 8;
FIG. 10 is a diagram of the ink injector system used in the present invention;
FIG. 11 is a perspective view partially cut away of a portion of the FIG. 10 ink injector
system;
FIG. 12 is a graphic representation of a damp rate curve defined by damp rate curve
data stored in the brink processor of FIG. 5; and
FIG. 13 is a graphic representation of an ink rate curve defined by ink rate curve
data stored in the drink processor of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] Referring particularly to FIG. 1, a printing press is comprised of one or more printing
units 10 which are controlled from a master work station 11. Each printing unit is
linked to the master work station by a unit controller 12 which communicates through
a local area network 13. As described in U.S. patent No. 4,667,323 (hereby incorporated
by reference), the master work station 11 and the unit controllers 12 may send messages
to each other through the network 13 to both control the operation of the press and
to gather production information.
[0013] Referring particularly to FIGS. 1 and 2, each printing unit 10 is comprised of four
units which are referred to as levels A, B, C and D and which are designated herein
as units 10A, 10B, 10C and 10D. The units 10A-D are stacked one on top of the other
and a web 15 passes upward through them for printing on one or both sides. In the
preferred embodiment shown, the printing units 10 are configured for full color printing
on both sides of the web, where the separate units 10A-D print the respective colors
blue, red, yellow and black.
[0014] As shown best in FIG. 2, each unit 10A-D includes two printing couples comprised
of a blanket cylinder 20 and a plate cylinder 21. The web 15 passes between the blanket
cylinders 20 in each unit for printing on both sides. Ink is applied to each plate
cylinder 11 by a series of ink transfer rollers 22 which receive in from an ink pickup
roller 23. As is well known in the art, the ink transfer rollers 22 insure that the
ink is distributed uniformly along their length and is applied uniformly to the rotating
plate cylinder 21. An ink rail 400 applies ink to a distribution ink drum 402 which
in turn transfers the ink to the ink pickup roller 23. Similarly, each plate cylinder
21 is supplied with dampening water by a pair of dampener transfer rollers 24 and
a dampener rider roller 25. A spray bar assembly 26 applies dampening water to each
of the dampener rider rollers 25.
[0015] Referring particularly to FIG. 3, each spray bar assembly 26 receives a supply of
pressurized water from a water supply tank 27 through a pump 28 and solenoid valve
29. The spray bar assembly 26 includes eight nozzles 30 which each produce a flat,
fan-shaped spray pattern of water when an associated solenoid valve 31 is energized.
When all eight solenoid valves 31 are energized, a thin line of water is sprayed along
the entire length of the associated dampener rider roller 25. As is well known in
the art, the solenoid valves 31 are pulsed on and off at a rate which is proportional
to press speed so that the proper amount of dampening water is applied and transferred
to the plate cylinder 21. It is also well known that means must be provided for separately
adjusting the amount of water sprayed by each nozzle 30 to account for variations
in the distribution of dampening water over the length of the plate cylinder 21.
[0016] The injector ink system delivers a controlled amount of ink to the distribution drum
402. Referring now to Figures 10 and 11. Each printing couple has four page packs
404. The page pack 404 is the part of the injector ink system which provides ink to
one age position. Page pack gearboxes 406 are located along a drive shaft in the arch
of the unit. Each gearbox 406 has a clutch arrangement to engage or silence each page
pack 404.
[0017] The page pack 404 provides ink to one page which consists of eight columns. Each
page pack 404 has eight variable stroke plungers 408 which pump a preset amount of
ink to each page column. The stroke of each plunger 408 is set by the ink adjustment
modules 410 which are located beneath the page pack 404.
[0018] The amount of ink fed to the ink train rollers is determined by:
1. The length of the plunger stroke at each column.
2. The operating speed of the ink motor which operates the page packs 404 and distribution
ink drum 402.
[0019] During unit operation, the ink motor is controlled by the proportional ink circuit
in the operator's console. This circuit will automatically vary ink motor speed with
press speed.
[0020] Located below each page pack 404 are a series of ink adjustment modules 410. There
are 8 ink adjustment modules 410 to a page pack 404 for a total of 32 per printing
couple. The ink adjustment module 410 adjusts an ink column by adjusting the stroke
of the page pack plunger 408 which increases or decreases the volume of ink fed to
the ink rail 410. Ink modules 410 are activated by the controls on a Unit Control
Panel, or from the operator's console.
[0021] When the ink motor is activated, an ink control rod 414 moves against a spring loaded
control lever 416. The control lever 416 and plunger assembly 408 are connected to
a common shaft. When the control rod 414 moves, it changes the position of the control
lever 416 which changes the length of the pump stroke, thereby changing the ink volume
being pumped to the ink rail 400. A mechanical stop 418 contacts the control lever
416 as shown.
[0022] A bidirectional motor 420 connected to the ink control rod 414 is provided for establishing
a "zero" position of the ink control rod which corresponds to a desired "black" printing
quality. The position of the bidirectional motor 420 is sensed by potentiometer 422
which outputs a signal which is stored in a memory either in the printing press or
a master work station. These stored values are "software zeroes" which are particular
to a type of paper, a type of ink and a type of dumping solution used in the printing
press. When one or all of these elements are changed in the printing press, the previously
stored "software zeroes" for this combination is downloaded to reset the ink adjustment
modules 410 to the correct zero setting.
[0023] The purpose of the ink rail 400 is to supply a predetermined amount of ink to the
distribution ink drum 402. The ink rail 400 is located in the aisle side of the unit
and extends across the full width of the unit. The rail is hinged so it can be pivoted
for cleaning and maintenance.
[0024] Ink from the four page packs 404 is pumped through connecting hoses 412 to openings
in the ink rail body. It then moves through the slots of the orifice plate which is
located in the center of the ink rail 400. The rail 400 is contoured and precisely
located near the surface of the distribution ink drum 402.
[0025] Referring to FIGS. 1 and 4, the spray bars 26 and ink rails 410 are operated by the
unit controllers 12. Each unit controller includes a communications processor 30 of
the type disclosed in the above-cited U.S. Patent No. 4,667,323 which interfaces with
the local area network 13. The communications processor 30 provides six serial communications
channels 31 through which it can receive input messages for transmission on the network
13. Messages which are received through the network 13 by the communications processor
30 are distributed to the appropriate serial channel 30. The serial communications
channels 30 employ a standard RS 422 protocol.
[0026] Four of the serial channels 30 connect to respective drink processors 35A, 35B, 35C
and 35D. Each drink processor 35 is coupled to sensing devices and operating devices
on a respective one of the levels A-D of the printing unit 10. In addition to receiving
a press speed feedback signal through a pair of lines 37 and press monitor and control
38 from a speed sensor 36 mounted on the units 10A, each drink processor 35A-D produces
output signals which control the solenoid valves 31 on the spray bars 26 and the page
packs 404 for the ink rail 400. The drink processors 35A-D also control color register.
[0027] Referring particularly to FIG. 5, each drink processor 35 is structured about a 23-bit
address bus 40 and a 16-bit data bus 41 which are controlled by a 16-bit microprocessor
42. The microprocessor 42 is a model 68000 sold commercially by Motorola, Inc. which
is operated by a 10 mHz clock 43. In response to program instructions which are stored
in a read-only memory (ROM) 44, the microprocessor 42 addresses elements of the drink
processor 35 through the address bus 40 and exchanges data with the addressed element
through the data bus 41. The state of a read/write (R/W) control line 45 determines
if data is read from the addressed element or is written to it. Those skilled in the
art will recognize that the addressable elements are integrated circuits which occupy
a considerable address space. They are enabled by a chip enable circuit 46 when an
address within their range is produced on the address bus 40. The chip enable circuit
46 is comprised of logic gates and three PAL16L8 programmable logic arrays sold commercially
by Advanced Micro Devices, Inc. As is well known in the art, the chip enable circuit
46 is responsive to the address on the bus 40 and a control signal on a line 47 from
the microprocessor 42 to produce a chip select signal for the addressed element. For
example, the ROM 44 is enabled through a line 48 when a read cycle is executed in
the address range $F00000 through $F7FFFF. The address space occupied by each of the
addressable elements in the drink processor 35 is given in Table A.
Table A
ROM 44 |
$F00000 |
to $F7FFFF |
RAM 50 |
$000000 |
to $06FFFF |
Programmable Interface |
Timer 60 |
$300340 |
to $30037F |
Timer 100 |
$300360 |
|
PC0 |
$300358 |
|
PC1 |
$300358 |
|
Programmable Interface |
Controller 70 |
$300380 |
to $3003BF |
Timer 85 |
$3003A0 |
|
Port PA |
$300390 |
|
Port PB |
$300392 |
|
PC3 |
$300398 |
|
Programmable Interface |
Controller 72 |
$3003C0 |
to $3003FF |
DUART 55 |
$200000 |
to $20003F |
[0028] Referring still to FIG. 5, whereas the ROM 44 stores the programs or "firmware" which
operates the microprocessor 42 to carry out the functions of the drink processor 35,
a read/write random access memory (RAM) 50 stores the data structures which are employed
to carry out these functions. As will be described in more detail below, these data
structures include elements which are collectively referred to herein as a switch
database 51, a control database 52, receive message buffers 49, and send message buffers
66. For example, the switch database 51 indicates the status of various switches on
the local control panels 53, whereas the control database 52 stores data indicative
of press speed, nozzle pulse rate, and nozzle pulse width and parameters for the ink
injector system. The RAM 50 is enabled for a read or write cycle with the microprocessor
42 through a control line 54.
[0029] The drink processor 35 is coupled to one of the serial channels 31 of the communications
processor 30 by a dual universal asynchronous receiver/transmitter (DUART) 55. The
DUART 55 is commercially available as an integrated circuit model 68681 from Motorola,
Inc. It operates to convert message data written to the DUART 55 by the microprocessor
42 into a serial bit stream which is applied to the serial channel 31 by a line drive
circuit 56 that is compatible with the RS 422 standard. Similarly, the DUART 55 will
receive a serial bit stream through a line receiver 57 and convert it to a message
that may be read by the microprocessor 42. The DUART 55 is driven by a 3.6864 mHz
clock produced by a crystal 58 and is enabled for either a read or write cycle through
control line 59.
[0030] The press speed feedback signal as well as signals from the local control panel 53
are input to the drink processor 35 through a programmable interface timer (PIT) 60.
The PIT 60 is commercially available in integrated circuit form as the model 68230
from Motorola, Inc. It provides two 8-bit parallel ports which can be configured as
either inputs or outputs and a number of separate input and output points. In the
preferred embodiment, one of the ports is used to input switch signals from the control
panel 53 through lines 60, and the second port is used to output indicator light signals
to the control panel 53 through lines 61. The PIT 60 is enabled through control line
62 and its internal registers are selected by leads A0-A4 in the address bus 40.
[0031] In addition to the parallel I/O ports, the PIT 60 includes a programmable timer/counter.
This timer may be started and stopped when written to by the microprocessor 42 and
it is incremented at a rate of 312.5 kHz by an internal clock driven by the 10 mHz
clock 43. When the timer is started, a logic high pulse is also produced at an output
63 to a speed interface circuit 64. When the interface circuit 64 subsequently produces
a pulse on input line 65, as will be described in detail below, the timer stops incrementing
and a flag bit is set in the PIT 60 which indicates the timer has stopped. This flag
bit is periodically read and checked by the microprocessor 42, and when set, the microprocessor
42 reads the timer value from the PIT 60 and uses it to calculate current press speed.
[0032] Referring still to FIG. 5, the solenoid valves 31 on each spray bar assembly 26 are
operated through a programmable interface controller (PIC) 70 or 72 and an associated
solenoid interface circuit 71 or 73. The PICs 70 and 72 are commercially available
integrated circuits sold by Motorola, Inc. as the model 68230. Each includes a pair
of 8-bit output registers as well as a single bit output indicated at 75 and 76. Each
output register can be separately addressed and an 8-bit byte of data can be written
thereto by the microprocessor 42. The two 8-bit bytes of output data are applied to
the respective solenoid interface circuits 71 and 73. As will be explained in more
detail below, the solenoid valves 31 are turned on for a short time period each time
a pulse is produced at the single bit output of the PICs 70 and 72. This output pulse
is produced each time an internal timer expires, and the rate at which the timer expires
can be set to a range of values by the microprocessor 42. The time period which each
solenoid valve 31 remains energized is determined by the operation of the solenoid
interface circuits 71 and 73, which in turn can be separately configured by writing
values to the registers in the PICs 70 and 72. As a result, the rate at which the
spray bars 26 are pulsed on is under control of the programs executed by the microprocessor
42, and the duration of the spray pulses from each nozzle 30 of the spray bars 26
can be separately controlled. Similarly, the ink injector system 424 having the page
packs 404, the ink adjustment modules 410 and the ink rail 400 is connected via interface
426 to the address bus 40 and tho data bus 41. Operation is substantially equivalent
to operation of the spray bars 26.
[0033] The solenoid interface circuit 71 is shown in FIG. 6 and it should be understood
that the interface circuits 73 and 426 are virtually identical. Each includes a set
of eight 8-bit binary counters 80 and a set of eight R/S flip-flops 81 and 82. The
counters 80 are available in integrated circuit form as the 74LS592 from Texas Instruments,
Inc. and they each include an internal 8-bit input register. This input register is
loaded with an 8-bit binary number on output bus 83 when a pulse is applied to an
RCK input of the counter 80. The RCK inputs of the eight counters 80 are connected
to respective ones of the output terminals PB0-PB7 of the PIC 70, and the eight leads
in the output bus 83 are driven by the output terminals PA0-PA7 of the PIC 70 through
a buffer 84. Thus, any or all of the registers in the counters 80 can be loaded with
a binary number on the PA output port of the PIC 70 by enabling the counter's RCK
input with a "1" on the corresponding lead of the PB output port. As will be described
in more detail below, this circuitry is used to separately preset each 8-bit counter
80 so that the time interval which each of the solenoid valves 30 remains on can be
separately controlled.
[0034] Referring still to FIG. 6, an output pulse is produced at the PC3 output pin of the
PIC 70 each time an internal timer 85 expires. The timer 85 is preset with a calculated
current pulse rate value by the microprocessor 42. Each time the timer 85 expires,
two phase displaced pulses are produced by a set of four D-type flip-flops 86-89.
The Q output of flip-flop 87 sets the RS flip-flops 81 on the leading edge of one
pulse and it presets four of the counters 80 with the values stored in their respective
input registers. On the trailing edge of this first pulse, the Q output of the flip-flop
87 returns to a logic low which enables the same four counters to begin counting.
The remaining four counters 80 and the R/S flip-flops 82 are operated in the same
manner by the Q and Q outputs of the flip-flop 89. The only difference is that the
operation of the flip-flop 89 is delayed one-half the time period between successive
pulses from the flip-flop 87.
[0035] The eight counters 80 are incremented by 2 kHz clock pulses until they reach the
all ones condition. At this point the output of the counter 80 goes to a logic low
voltage and it resets the R/5 flip-flop 81 or 82 to which it connects. The output
of each R/S flip-flop 81 or 82 control the operation of one of the solenoid valves
31 through power drivers 90 and 91 and, thus, each valve 31 is turned on when the
flip-flops 81 and 82 are set, and they are each turned off as their associated counter
80 overflows and resets its R/S flip-flop. The outputs of the drivers 90 are connected
to the first, third, fifth and seventh nozzle solenoids and the outputs of the drivers
91 are connected to the second, fourth, sixth and eighth nozzle solenoids. As a result,
nozzles 1, 3, 5 and 7 are turned on each time a pulse is produced at PIC output terminal
PC3 and nozzles 2, 4, 6 and 8 are turned on a short time interval later (i.e. greater
than 5 milliseconds later). Each nozzle 30 is then turned off separately as their
corresponding counters 80 overflow. It should be apparent, therefore, that the spray
bar solenoids are pulsed on at the same rate, but the duration of each is left on,
and hence the amount of dampening water delivered to the fountain roller 25, is separately
controllable by the value of the 8-bit binary numbers loaded into the respective counter
input registers.
[0036] Referring particularly to FIGS. 5 and 7, the speed interface circuit 64 couples the
digital incremented speed feedback signal received from the speed sensor 36 to the
PIT 60. The speed sensor 36 produces a logic high voltage pulse for each incremental
movement of the web through the printing unit. In the preferred embodiment, a magnetic
sensor model 1-0001 available from Airpax Corporation is employed for this purpose,
although any number of position feedback devices will suffice. The speed sensor's
signal is applied to a line receiver 95 which produces a clean logic level signal
that is applied to the input of a 4-bit binary counter 96. The counter 96 produces
an output pulse each time sixteen feedback pulses are produced by the speed sensor
36. This overflow is applied to the clock terminal of a D-type flip-flop 97 which
switches to a logic state determined by the logic state applied to its D input. The
D input is in turn driven by a second flip-flop 98 which is controlled by the PCO
output of the PIT 60 and the Q output of flip-flop 97.
[0037] When the press speed is to be sampled, a "1" is written to the PCO output of the
PIT 60. This transition clocks the flip-flop 98 to set its Q output high and to thereby
"arm" the circuit. As a result, when the next overflow of the 4-bit counter 96 occurs,
the flip-flop 97 is set and a logic high voltage is applied to the PG2TIN and PC1
inputs of the PIT 60. The Q output of flip-flop 97 also goes low to reset flip-flop
98 and to thereby disarm the circuit. As long as input PC2TIN is high, an internal
timer 100 in the PIT 60 is operable to measure the time interval. The input PC1 may
be read by the microprocessor 42 to determine when a complete sample has been acquired.
After sixteen feedback pulses have been received, the counter 96 again overflows to
reset the flip-flop 97 and to thereby stop the timer 100 in the PIT 60. Input PC1
also goes low, and when read next by the microprocessor 42, it signals that a complete
sample has been acquired and can be read from the PIT 60. The entire cycle may then
be repeated by again writing a "1" to the PCO output of the PIT 60.
[0038] While many means are available for inputting an indication of press speed, the speed
feedback circuit of the present invention offers a number of advantages. First, the
effects of electronic noise on the measured speed are reduced by the use of the counter
96. The error caused by a noise voltage spike on the input lines is effectively reduced
to about one sixteenth the error that would result if speed were measure by sensing
the feedback pulse rate directly. In addition, by using the timer in the PIT 60 to
record the time interval and save the result, the microprocessor 42 is not burdened
with a continuous monitoring of the speed feedback signal. Instead, when the system
requires an updated sample of press speed, the microprocessor checks the PIT 60 and
reads the latest value stored therein. It then initiates the taking of another sample
and continues on with its many other tasks.
[0039] Referring to FIG. 8, the data structures which are employed by the preferred embodiment
of the present invention to control the spray bars 26 are stored in the RAM 50. An
equivalent data structure is provided for the ink injector system and only the data
structure for the spray bars will be described in detail. As indicated above, these
data structures are collectively referred to as the switch database 51 and the control
database 52. The structure of these two databases 51 and 52 are illustrated in FIG.
8 for one printing couple. Similar data is stored in the databases 51 and 53 for the
other printing couple in the unit 10.
[0040] The switch database 51 includes an image of the switch states on the local control
panel 53 (FIG. 5). The operator depresses a "FLOOD" switch when extra dampening water
is to be applied during startup. As will be described below, when this occurs, the
dampening water flow rate is increased 25% for a preset time interval. To support
these functions, a flood switch status word 120, a flood switch examine flag 121 and
a flood timer value 122 are stored in the RAM 50. Flood switch status 120 is updated
every 100 milliseconds as will be described below to reflect the current state of
the control panel switch. The other two data structures are employed to recognize
the flood request and implement the request for a preset time interval.
[0041] When an autoflood signal is received from the press monitor and control 38 during
automatic sequencing at the beginning of a press run, dampening water is also increased.
The status of this signal is stored at an autoflood switch status word 123, and as
long as it is present, increased dampening water will be produced. And finally, the
dampening system can be disabled by the operator and this event is stored at 124.
[0042] A number of other data structures are contained in the switch database 51, at least
one of which pertains to the ink rate control system for the printing unit 10.
[0043] The data structures in the control database 52 which are required by the dampening
system are illustrated in FIG. 8. These include a control status 125 which indicates
if the control is in the process of making a requested change ("change in progress")
or if no changes have been requested ("idle"). Control status 125 also includes a
"changes not complete counter" which indicates at any time the number of controllable
nozzles which are undergoing changes. A dampener mode word 126 indicates if the dampening
system is in either manual or automatic mode. In the manual mode the dampening flow
rate is set to a value indicated as unit trim 127, which can be manually altered from
the master work station 11 or a local panel 53 (FIG. 1). In the automatic mode, the
dampening water flow rate is calculated as a function of press speed in accordance
with stored rate curve data 128 as will be described in more detail below.
[0044] A flood request flag 129 is set when the flood function is being performed and an
update flag 130 is set when a significant change in press speed has occurred or new
rate curve data 128 has been down loaded from the master work station 11. As will
be explained in detail below, the press speed is measured every 100 milliseconds and
stored as the instantaneous press speed 131. If the instantaneous press speed 131
differs by more than ±.5% from a processed press speed stored at 132, then the processed
press speed 132 is updated with the newly measured value and the update flag 130 is
set. The processed press speed 132 is used in combination with the rate curve data
128 to calculate a new dampening water flow rate when the dampening system is in the
"AUTO" mode. This is converted to a pulse rate and is modified by a stored couple
trim value 133 and increased further if the flood request flag 130 is set. The resulting
current pulse rate value is stored at 134 and is output to the timer 85 in the PIC
70 (FIG. 6). The couple trim value 133 may be changed from the local control panel
53 to provide a means for manually adjusting the dampening water flow rate while in
the AUTO mode. A current % flow value stored at 137 is a number which may be read
out and displayed. It expresses the current pulse rate value 134 as a percentage of
the maximum pulse rate value and, hence, it indicates the percentage of maximum dampening
water flow rate which is currently being applied.
[0045] Not only is the pulse rate applied to the spray bar nozzles 30 controlled, but also,
the width of each pulse is separately controlled. This function is supported by a
nozzle data block 135. The data block 135 stores information on each of the eight
controllable nozzles 30 which will be described in more detail below with respect
to FIG. 9C.
[0046] The rate curve data 128 is illustrated in detail in FIG. 9A. It may include one or
more rate curve data blocks 140 that may be used with one or both printing couples.
Each data block 140 includes a rate curve ID 141 which uniquely identifies it. Each
printing couple is associated with a particular rate curve data block by this rate
curve ID number. As illustrated in FIG. 9B, a configuration database stored in the
RAM 50 includes configuration records 142 for each printing couple. These configuration
records 142 include a rate curve ID number which link each printing couple to one
of the stored rate curve data blocks 140. These configuration records 142 can be altered
by messages from the master work station 11 and, hence, the rate curve data block
140 associated with a particular printing couple can be altered at any time.
[0047] Each rate curve data block 140 also stores a rate curve value 143 which indicates
the current dampening water flow rate as calculated from the data in this rate curve
data block 140 and the processed press speed 132. A third entry in the block 140 is
the number of rate curve points which are stored in this data block 140 and the remainder
of the data block 140 is comprised of the data which defines each of these points.
Each point is defined by a press speed number 144 and a flow percent number 145. Anywhere
from two to ten points may be stored which indicate the desired dampening water flow
rates across a range of press speeds. As will be described in more detail below, the
rate curve value 143 is calculated by linearly interpolating between the flow percent
numbers 145 for the points which have press speed numbers 144 to each side of the
processed press speed 131. An example of the curves for the control of the spray bars
26 is depicted in FIG. 12 and the curves for the control of the ink injector system
is depicted in FIG. 13.
[0048] Referring particularly to FIGS. 9B and 9C, each printing couple may have up to eight
separately controllable nozzles 30 on its spray bar 26. The number is indicated in
the configuration record 142 for each couple. The nozzle data block 135 in the control
database 52 stores data on each controllable nozzle 30. More specifically, the status
150 of each nozzle is stored (idle/change requested/change in process). Also, stored
in this block 135 is the current pulse width value 151 which indicates the value actually
being output to the PIC 70 or 72 (FIG. 5), the desired pulse width value 152 which
indicates the pulse width which has been commanded, and the normalized pulse width
value 153 which indicates the current value unmodified by any flood request or the
like. The nozzle data block 135 is employed to control each nozzle 30 and to implement
a change in the pulse width produced by each nozzle 30 in response to messages received
over the serial link 31 from the communications processor 30 (FIG. 4).
[0049] The programs which direct the operation of the microprocessor 42 and, hence, control
the operation of the drink processor 35 are stored in the ROM 44. These programs include
a set of programs which carry out specific tasks or processes as well as a real time
clock interrupt service routine and an operating system program.
[0050] The development of software for the microprocessor 42 can be performed in numerous
different ways by one skilled in the art. One software embodiment for controlling
the spray bar assembly 26 is disclosed in U.S. Serial No. filed (hereby
incorporated by reference). The control of inking can be accomplished with a similar
software program.
[0051] The invention is not limited to the particular details of the apparatus depicted
and other modifications and applications are contemplated. Certain other changes may
be made in the above described apparatus without departing from the true spirit and
scope of the invention herein involved. It is intended, therefore, that the subject
matter in the above depiction shall be interpreted as illustrative and not in a limiting
sense.
1. A control system for operating at least one set of nozzles on a spray bar and at
least one set of plungers on an ink injection device for a printing press, comprising:
memory means for storing at least damp rate curve data and ink rate curve data which
is utilized to control operation the nozzles and plungers, respectively;
means for processing connected to the memory means, the means for processing providing
a damp rate control signal as a function of the damp rate curve data and providing
an ink rate control signal as a function of the ink rate curve data;
first interface means for connecting the set of nozzles to the means for processing
and being responsive to the damp rate control signal to control operation of the nozzles;
second interface means for connecting the set of plungers to the means for processing
and being responsive to the ink rate control signal to control operation of the plungers;
means for communicating connected to at least said memory means and being operable
in response to a received rate curve message to alter the damp rate curve data and
the ink rate curve data stored in the memory means.
2. The control system according to claim 1, wherein each of the damp rate and ink
rate curve data includes a plurality of points, and wherein each point in the damp
rate and ink rate curve data indicates the amount of damping solution and ink required
at a specific press speed.
3. The control system according to claim 1, wherein said ink rate curve data comprises
a primary ink rate curve composed of a plurality of data points connected together
by interpolation of the data points and first and second secondary ink rate curves
which are displaced from the primary ink rate curve by positive and negative factors,
respectively, said positive and negative factors being a predetermined percentage
of a greatest point of data of said plurality of data points of said primary ink rate
curve, the points indicating the amount of ink required at a specific press speed.
4. The control system according to claim 3, wherein the predetermined percentage is
20%.
5. The control system according to claim 3, wherein the plurality of data points is
ten data points and are connected together by straight line segments.
6. The control system according to claim 1, wherein the damp rate curve data comprises
a damp rate curve composed of a plurality of data points connected together by an
interpolation of the data points, the data points indicating the amount of damping
water required at a specific press speed.
7. The control system according to claim 6, wherein the plurality of data points is
ten data points and are connected together by straight line segments.
8. The control system according to claim 1, wherein the memory means stores a plurality
of different ink rate curve data and a plurality of different damp rate curve data
as a function of paper type, ink type and damping solution used in the printing press.
9. The control system according to claim 1, wherein the means for communicating is
connected to a master work station and wherein the master work station stores a plurality
of different ink rate curve data and a plurality of different damp rate curve data,
each being a function of paper type, ink type and damping solution used in the printing
press.
10. A control system for operating at least one set of nozzles on a spray bar and
at least one set of plungers on an ink injection device for a printing press, comprising:
memory means for storing at least damp rate curve data and ink rate curve data which
is utilized to control operation the nozzles and plungers, respectively;
means for processing connected to the memory means, the means for processing providing
a damp rate control signal as a function of the damp rate curve data and providing
an ink rate control signal as a function of the ink rate curve data;
first interface means for connecting the set of nozzles to the means for processing
and being responsive to the damp rate control signal to control operation of the nozzles;
second interface means for connecting the set of plungers to the means for processing
and being responsive to the ink rate control signal to control operation of the plungers;
means for communicating connected to at least said memory means and being operable
in response to a received rate curve message to alter the damp rate curve data and
the ink rate curve data stored in the memory means, the damp rate and ink rate curve
data including a plurality of points, each point in the damp rate and ink rate curve
data indicating the amount of damping solution and ink, respectively, required at
a specific press speed.
11. The control system according to claim 10, wherein said ink rate curve data comprises
a primary ink rate curve composed of a plurality of data points connected together
by interpolation of the data points and first and second secondary ink rate curves
which are displaced from the primary ink rate curve by positive and negative factors,
respectively, said positive and negative factors being a predetermined percentage
of a greatest point of data of said plurality of data points of said primary ink rate
curve, the points indicating the amount of ink required at a specific press speed.
12. The control system according to claim 11, wherein the predetermined percentage
is 20%.
13. The control system according to claim 12, wherein the plurality of data points
is ten data points and are connected together by straight line segments.
14. The control system according to claim 10, wherein the damp rate curve data comprises
a damp rate curve composed of a plurality of data points connected together by an
interpolation of the data points, the data points indicating the amount of damping
water required at a specific press speed.
15. The control system according to claim 14, wherein the plurality of data points
is ten data points and re connected together by straight line segments.
16. The control system according to claim 10, wherein the memory means stores a plurality
of different ink rate curve data and a plurality of different damp rate curve data
as a function of paper type, ink type and damping solution used in the printing press.
17. The control system according to claim 10, wherein the means for communicating
is connected to a master work station and wherein the master work station stores a
plurality of different ink rate curve data and a plurality of different damp rate
curve data as a function of paper type, ink type and damping solution used in the
printing press.
18. A control system for operating at least one set of nozzles on a spray bar and
at least one set of plungers on an ink injection device for a printing press, comprising:
memory means for storing at least damp rate curve data and ink rate curve data which
is utilized to control operation the nozzles and plungers, respectively;
means for processing connected to the memory means, the means for processing providing
a damp rate control signal as a function of the damp rate curve data and providing
an ink rate control signal as a function of the ink rate curve data;
first interface means for connecting the set of nozzles to the means for processing
and being responsive to the damp rate control signal to control operation of the nozzles;
second interface means for connecting the set of plungers to the means for processing
and being responsive to the ink rate control signal to control operation of the plungers;
means for communicating connected to at least said memory means and being operable
in response to a received rate curve message to alter the damp rate curve data and
the ink rate curve data stored in the memory means, each of the damp rate and ink
rate curve data including a plurality of points, and wherein each point in the damp
rate and ink rate curve data indicates the amount of damping solution and ink required
at a specific press speed, the ink rate curve data having a primary ink rate curve
composed of a plurality of data points connected together by interpolation of the
data points and first and second secondary ink rate curves which are displaced from
the primary ink rate curve by positive and negative factors, respectively, said positive
and negative factors being a predetermined percentage of a greatest point of data
of said plurality of data points of said primary ink rate curve, the points indicating
the amount of ink required at a specific press speed.
19. The control system according to claim 18, wherein predetermined percentage is
20%.
20. The control system according to claim 18, wherein the plurality of data points
is ten data points and are connected together by straight line segments.
21. The control system according to claim 18, wherein the damp rate curve data comprises
a damp rate curve composed of a plurality of data points connected together by an
interpolation or the data points, the data points indicating the amount of damping
water required at a specific press speed.
22. The control system according to claim 21, wherein the plurality of data points
is ten data points and re connected together by straight line segments.
23. The control system according to claim 18, wherein the memory means stores a plurality
of different ink rate curve data and a plurality of different damp rate curve data
as a function of paper type, ink type and damping solution used in the printing press.
24. The control system according to claim 18, wherein the means for communicating
is connected to a master work station and wherein the master work station stores a
plurality of different ink rate curve data and a plurality of different damp rate
curve data as a function of paper type, ink type and damping solution used in the
printing press.