JPH0284338A - Apparatus for automatic control of printing density and gradation in printing press - Google Patents

Abstract

PURPOSE:To enhance the controllability of the thickness of an ink film and that of a water film by comparing the detection signals of the thicknesses of the ink film and water film on an ink roll and the detection signal of the concn. of isopropyl alcohol with preset values and controlling the number of rotations of an ink fountain roller and those of a water fountain roller on the basis of the obtained control signal. CONSTITUTION:An ink film thickness detection signal I, a water film thickness signal I, a water film thickness detection signal W and an isopropyl alcohol concn. detection signal A are compared with preset values and the obtained ink film thickness detection signal I is compared with a set value and the number of rotations of an ink fountain roller 9 are controlled on the basis of an ink fountain roller rotation control signal kr through an ink preset apparatus 23. The water film thickness detection signal W is compared with a set value and the number of rotations of a water fountain roller 13 is controlled on the basis of a water fountain roller rotation control signal Kw through a motor driving device 21. In the same way, the isopropyl alcohol concn. detection signal A is compared with a set value to obtain a control signal and the number of rotations of a supply pump 26 of a 100% isopropyl alcohol solution are controlled on the basis of the control signal and the supply amount of the 100% isopropyl alcohol solution to a dampening water pan 12 is changed to hold the ink film thickness, the water film thickness and isopropyl alcohol concn. to the set values.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic control device for printing density and gradation of a printing press.

(Prior art) The automatic control device for print density and gradation of a conventional printing press is
To explain with the diagram, (1) is the impression cylinder, (2) is the bracket cylinder, (3) is the paper, (4) is the plate cylinder, (5) is the ink forming roller, and (6) is the first landing side swing. (7) is the ink roller group, (8) is the delivery roller, (9) is the ink source roller (10) is the ink key, and the opening degree (see δ) of the ink key (10) and the delivery roller (8) are The amount of ink supplied to the ink roller group (7) is controlled by the rotation speed. Also, (11) is the second landing side swinging roller, (12) is the dampening pan, (13) is the water source roller, (14) is the transmission roller, (15) is the water roller, (
16) is an ink film thickness/moisture content (ratio) sensor, and a first landing side swinging roller (6) is installed downstream of the ink roller group (7).
An ink film thickness/moisture content sensor (16) is provided near the first landing side swinging roller (6).

In addition, (17) is the ink film thickness/moisture content sensor (16)
Width-direction moving rails (18
) is the sensor amplifier, and (19) is the controller.

(20) is a setting device, (21) and (22) are a motor drive device, (23) is an ink presetting device, (24) is a pulse motor for movement in the width direction, and (25) is a drive motor for a water base roller.

(-) is the water film thickness detection signal, and (I) is the ink film thickness detection signal.

(Ni- is the water head roller rotation speed control signal, (Ln) is the sensor movement control signal, (n) is the ink cartridge number signal, (K
i) is 1 with the ink key opening signal.Ink source roller (9) - delivery roller (8) - ink roller group (7)
-The first landing side swinging roller (6) and the second landing side swinging roller (
11) - While transferring the ink onto the plate of the plate cylinder (4) via the ink forming roller (5), the dampening water in the dampening water pan (12) adhering to the surface of the water base roller (13) is transferred to the same water. Former roller (13
) and the transmission roller (14), and then transferred onto the plate of the plate 1ri (4) via the transmission roller (14) and the swimsuit roller (15). Also, the plate cylinder (4)
Due to the difference in adhesion strength between the ink and dampening water transferred onto the 5th printing plate, the ink adheres to the printed area and the dampening water It adheres to non-print areas and separates the ink and dampening water.

In addition, the remaining dampening water outside the dampening ice field adhering to the non-image areas on the plate emulsifies with the ink, causing the ink roller group (7) to
flows towards. At this time, since the dampening water and the ink headed for the ink formation roller (5) are passed through the first destination side swinging roller (6), the dampening water and the ink headed for the ink formation roller (5) are arranged near the first destination side swinging roller (6). Detected by an ink film thickness/moisture content sensor (16). This dampening water and ink indirectly indicates the amount of dampening water and ink on one plate, so the water film thickness and ink film thickness can be measured on the surface of the first landing side swinging roller (6). When detected,
The quantitative relationship between the water film thickness and the ink film thickness on the Gi (3) surface can be estimated. Since there is a close relationship between the quantitative relationship between the water film thickness and ink film thickness and the print density and gradation, the sensor movement control signal (Ln) is sent from the controller (19) to the motor drive device (22). Send the same motor drive device (2
2), the ink film thickness/moisture content sensor (16) is reciprocated along the width direction movement rail (17). Further, the water film thickness detection signal (-) and the ink film thickness detection signal (1) obtained by the ink film thickness/moisture content sensor (16) are sent to the controller (19) via the sensor amplifier (18).
Compare the water film thickness detection signal (currency) with the preset value set in the controller (19).

The water head roller rotation speed control signal (Kw) obtained as a result of the calculation is sent to the motor drive device (21), and the water head roller drive motor (25) is sent via the motor drive device (21).
) and the rotation speed of the water head roller (13).

The above ink film thickness detection signal (1) and the above controller (
Compare and calculate the setting value set in advance in 19),
The resulting ink key opening signal (Ki) can be used as an ink preset device. i! (23) and controls the opening degree of the ink key (10) via the ink presetting device (23) to adjust and maintain the supply amount of dampening water and ink at the set values. ing.

(Problems to be Solved by the Invention) In the conventional automatic printing density and gradation control device of the printing press shown in FIG. In order to change the ink supply, a large number of ink keys (lO) are arranged in the width direction, and the opening degree (see δ) of each can be increased or decreased independently, so let's adjust the ink supply amount over the entire width in the width direction. In this case, it is necessary to scan the entire area in the axial direction of the first landing side swinging roller (6) with the ink film thickness/moisture content sensor (16).
Focusing on a divided section corresponding to a certain ink key (10), after the ink film thickness/water content sensor (16) detects the ink film thickness and water film thickness of the same divided section, it returns to the same divided section again. Until the ink film thickness and water film thickness are detected, the controllability of the ink film thickness and water film thickness is poor. In addition, since the ink film thickness/moisture content sensor (16) reciprocates in the axial direction of the first landing side swinging roller (6),
This poses a problem in that it not only obstructs printing work but also impairs the safety of printing work.

The present invention has been proposed in view of the above problems, and its purpose is to improve the controllability of ink film thickness and water film thickness. Another object of the present invention is to provide an automatic control device for printing density and gradation of a printing press that does not interfere with printing operations and can ensure the safety of printing operations.

(Means for Solving the Problems) In order to achieve the above objects, two automatic control devices for printing density and gradation of a printing press of the present invention are configured to control the ink film thickness, water film thickness, and isopropyl alcohol on the ink roller. The density detection device compares and calculates the detection signal from the detection device with a preset setting value, and sends the control signal obtained as a result to the ink source roller and the water source roller. The ink roller has a controller for controlling the number of revolutions of the original roller, and the detection device is fixedly supported at any position in the width direction near the ink roller.

(Function) The automatic printing density and gradation control device of the printing press of the present invention is configured as described above, and the controller is configured based on the widthwise coverage distribution information from the ink presetting device prior to the start of printing. The ink film thickness/moisture content sensor and the isopropyl alcohol concentration sensor are moved in the width direction and fixed at arbitrary positions in the width direction, and then the ink film is moved. The ink film thickness detection signal and water film thickness detection signal detected by the thickness/water content sensor and the isopropyl alcohol concentration detection signal detected by the isopropyl alcohol concentration sensor are sent to the controller.

The ink film thickness detection signal, the water film thickness detection signal, and the isopropyl alcohol concentration detection signal are compared and calculated with preset values, and the ink film thickness detection signal and the set value are compared and calculated. An ink source roller rotation speed control signal is sent to the ink source roller via an ink presetting device to adjust the rotation speed of the ink source roller. Further, the water base roller rotation speed control signal obtained by comparing and calculating the water film thickness detection signal with a set value is sent to the water base roller drive system to adjust the rotation speed of the water base roller. In addition, the pump rotation speed control signal obtained by comparing and calculating the isopropyl alcohol concentration detection signal with the set value is sent to the isopropyl alcohol 100% liquid supply pump, and the rotation speed of the supply pump is adjusted. The ink film thickness, water film thickness, and isopropyl alcohol concentration are maintained at set values by changing the supply amount of the 100% isopropyl alcohol solution supplied from the dampening water pan to the dampening water pan.

(Embodiment) Next, an automatic control device for printing density and gradation of a printing press according to the present invention will be explained using an embodiment shown in Fig. 1.2. (1) in Fig. 1 is an impression cylinder, (2) is the bracket body.

(4) is the plate cylinder, (5) is the ink forming roller, and (6) is the first
Arrival side (moving roller, (7) is the ink roller group, (8) is the delivery roller, (9) is the ink source roller, (10) is the ink key, and the opening degree of the same ink key (10) and the delivery roller (8) The amount of ink supplied to the ink roller group (7) is controlled by the rotation speed of the ink roller group (7). Also, (ll) is the second landing side swinging roller, (12) is the dampening water pan, and (13) is the second landing side swinging roller. is the water base roller, (14) is the transmission roller,
(15) is the water roller group, (16) is the ink roller group (7
) is an ink film thickness/water content sensor that detects the ink film thickness and water film thickness, (51) is an isopropyl alcohol concentration sensor that detects isopropyl alcohol concentration, (1)
7) is a width-direction moving rail that supports the detection device (16) so as to be movable in the width direction, and the detection device (16) is moved to any position near the ink roller group (7) by the width-direction movement rail (17). It is supported so that it can be fixed in position. Also (18
) is the amplifier for the detection device, (19) is the controller, (
20) is the setting device, (21) and (22) are the motor drive device, (23) is the ink presetting device, (24) is the pulse motor for moving in the width direction, (25) is the drive motor for the water base roller, Fig. 2 (26) is a supply pump for 100% isopropyl alcohol, (27) is an alcohol pan, and 100% isopropyl alcohol is supplied from the alcohol pan (27) to the dampening water pan (12). .

In Fig. 1, (Ka) is the water film thickness detection signal, (I) is the ink film thickness detection signal, (A) is the isopropyl alcohol concentration detection signal, (Kw) is the water base roller rotation speed control signal, (L
n) is a control signal for moving the detection device, (m) is widthwise drawing rate distribution information, and (Kr) is an ink source roller rotation speed control signal.

Next, the operation of the automatic control device for printing density and gradation of the printing press shown in FIG. 1.2 will be explained in detail.

Figure 4 shows isopropyl alcohol (IPA)? It shows the relationship between the water film thickness of the plate and the gradation using 1 degree as a parameter. The relative contrast values shown in Figure 3 are as follows:
It is a quantity defined by (1-DI/DV).

Here, Dll is the density of the halftone dot portion, and D9 is the solid density. It is said that the higher the value of this relative contrast, the better the 9th gradation, and in any of the figures in FIG. 4, the thinner the water film thickness of the first plate, the better the 1st gradation. However, if the water film thickness of the plate is made too thin, it will become 1.For example, if it is made thinner than X in Figure 4 [a1],
Ink adheres to non-image areas where ink should not originally adhere, and no image is formed. This Xl is called the lower limit concentration. In order to improve the gradation, the water film thickness of one plate should be controlled to be close to x1. However, the thickness of the water film on the plate varies considerably depending on the type of ink.

That is, when the isopropyl alcohol concentration in the dampening solution increases, it contributes to increasing the relative contrast, and in Fig. 4 [a1], when the water film thickness of the 9th plate increases from 0°3 to 1.0 μm. The degree of decrease in relative contrast K (if is approximately 0.0 for any isopropyl alcohol concentration)
It is 2. In order to return from the state where the relative contrast value is 0.28 to the original state where the relative contrast value is 0.30, the water film thickness of one plate may be set to 0.3 μm. For this reason, conventionally, the number of rotations of the water fountain roll (13) has been reduced, but even if the isopropyl alcohol concentration in the dampening water is increased from 10% to 25%, the relative contrast remains at a value of 0. It is possible to keep it at 30. Such a situation can also be seen in FIG. 4 [a2]. In this case, if the isopropyl alcohol concentration is low, the flat area of the upwardly convex part will be long, and as the concentration increases, 1
The curve drops sharply as the water film thickness of the plate increases. In this case as well, it is possible to respond to the decrease in the relative contrast value and to make changing the water film thickness of one printing plate equivalent to changing the isopropyl alcohol concentration. The most extreme example is the case shown in FIG. 4 [a,]. At any isopropyl alcohol concentration, the thinner the water film thickness of one plate, the higher the relative contrast and the better the third gradation. This trend is the same as in other examples.

However, in the region where the isopropyl alcohol concentration is extremely low, as in the example in Figure 4 [a2], the convex plateau region is long toward the top, and in the region where the isopropyl alcohol concentration is extremely high, the relative contrast decreases as the water film thickness of the first plate increases. There is a tendency for the value to decrease rapidly and then gradually decrease or become flat, and in the intermediate isopropyl alcohol concentration range, it shows intermediate behavior. Furthermore, in a region where the isopropyl alcohol concentration changes rapidly, the relative contrast (K) value shows an extremely stable value. To explain an example of the behavior in this region, if the value of relative contrast changes from 0.3 to 0.28 due to disturbance, the water film thickness of the first plate is 1
．． The concentration of isopropyl alcohol changes from 0 μI to 1.5 μm, but the concentration of isopropyl alcohol remains constant. Value = relative contrast
To return the relative contrast from the state of 0.28 to the original state of value = 0.30, the water film thickness of the first plate was changed from 1.5μI to 1.5μI.
Although it may be returned to 0 μm, it is possible to increase the isopropyl alcohol concentration from 10% to 20% and still maintain the relative contrast value = 0.30. The smaller the range of change due to disturbance in this relative contrast value, the smaller the range of change in the water film thickness of one plate.

The range of change in isopropyl alcohol concentration also becomes smaller. On the other hand, the tendency is the same when the relative contrast increases from a value of 0.30. Figure 4 shows how the isopropyl alcohol concentration changes rapidly [
The region (^) of [a3] shows extremely stable relative contrast values. The present invention focuses on the above points, and
Print density and gradation are automatically controlled.

That is.

In the conventional case, the controller (19) outputs an ink key opening signal (Ki) to the ink key (10), but in the automatic printing density and gradation control device of the printing press of the present invention, An ink source roller rotation speed control signal (Kr) is output to the source roller (9). Further, the ink presetting device (23) outputs widthwise drawing rate distribution information (m) to the controller (19). The controller (19) receives widthwise drawing rate distribution information (+w) from the ink presetting device (23) before starting printing.
The control signal is calculated based on.

The detection device movement control signal (Ln) obtained as a result is sent to the motor drive device (22).
) to move the ink film thickness/moisture content sensor (16) and isopropyl alcohol concentration sensor (51) to the width direction moving rail (1).
The ink film thickness detection signal (1) and the water film thickness detection signal (
-) and the isopropyl alcohol concentration detection signal (A) detected by the isopropyl alcohol 8 degree sensor (51)
are sent to the controller (19) via the amplifier (18), where the ink film thickness detection signal (1), water film thickness detection signal (Ka), and isopropyl alcohol concentration detection signal (^) are sent to the controller (19).
The ink film thickness detection signal (1) and the set value are compared and calculated, and the ink source roller rotation speed control signal (ni r) obtained by comparing and calculating the ink film thickness detection signal (1) with the set value is set as the ink preset. The ink is sent to the ink source roller (9) via the device (23) to adjust the rotation speed of the ink source roller (9). In addition, the water base roller rotation speed control signal (Kaga) obtained by comparing and calculating the water film thickness detection signal (-) with the set value is sent to the motor drive device (21). ) to control the water head roller drive motor (25) to adjust the rotation speed of the water head roller (13). Also, compare the isopropyl alcohol concentration detection signal (A) with the set value.

The calculated pump rotation speed control signal is sent to the isopropyl alcohol 100% liquid supply pump (26),
By adjusting the rotation speed of the supply pump (26) and changing the amount of 100% isopropyl alcohol supplied from the alcohol pan (27) to the dampening water pan (12), the ink film thickness and water film thickness can be adjusted. and isopropyl alcohol concentration at set values.

FIG. 3 shows the behavior of dampening water and isopropyl alcohol in the ink in the ink roller group (7).

That is, the left half of FIG. 3 shows the configuration of the ink roller group, and the right half shows the behavior of each component in the ink roller group between B and Z. As the water fraction in the dampening solution supplied at two points (Z roller) increases to the ink source of the ink roller group, it increases from 90% to 95%, while the isopropyl alcohol concentration in the dampening solution increases from 10% to 5%. %
is rapidly declining. On the other hand, the ink flows from the ink source, and as the amount of solvent in the ink moves downward, it mutually dissolves in isopropyl alcohol to form an isopropyl alcohol/solvent emulsion in water (0/W type). Also, as the isopropyl alcohol in the fountain solution moves upward, it dissolves into the solvent in the ink flowing from above.

It increases as the isopropyl alcohol in the solvent moves downward. The behavior of isopropyl alcohol at this time is detected by an isopropyl alcohol concentration sensor (51). An example thereof will be explained with reference to FIGS. 4(b), (c), and (d). Now, when the value of relative contrast suddenly decreases as shown in Figure 4(b) due to disturbance, you can use isopropyl alcohol instead of changing the rotation speed of the water base roller (13) based on the ink film thickness and water content. Even if the density is changed slowly and gradually, the relative contrast quickly returns to the original value of 1.

Good controllability.

During the above control, the isopropyl alcohol concentration rapidly increases at the two points (Z roller) in Figure 3, and when it reaches about 20%, the isopropyl alcohol concentration at the isopropyl alcohol concentration sensor (51) (K roller) It was saturated at 15% and became steady (see FIG. 4(b)). Although the isopropyl alcohol concentration changes over a wide concentration range, the relative contrast value gradually approaches a constant value, thereby controlling the decrease in concentration. The changes when the value of relative contrast increases are shown in FIG. 4(C).

The conventional device has poor controllability as shown in FIG. 4(d).

(Effects of the Invention) As described above, in the automatic control device for printing density and gradation of a printing press according to the present invention, the controller sends a control signal based on the widthwise drawing rate distribution information from the ink presetting device prior to the start of printing. The ink film thickness/moisture content sensor and the isopropyl alcohol concentration sensor are moved in the width direction and fixed at arbitrary positions in the width direction using the control signal for moving the detection device obtained as a result. The ink film thickness detection signal and water film thickness detection signal detected by the rate sensor and the isopropyl alcohol concentration detection signal detected by the isopropyl alcohol concentration sensor are sent to the controller, where the ink film thickness detection signal and water film thickness detection signal are Compare the isoprobil alcohol concentration detection signal with the preset value.

Calculate and compare the ink film thickness detection signal with the set value.

The ink source roller rotation speed control signal obtained through the calculation is sent to the ink source roller via the ink presetting device to adjust the rotation speed of the ink source roller. Further, the water base roller rotation speed control signal obtained by comparing and calculating the water film thickness detection signal with a set value is sent to the water base roller drive system to adjust the rotation speed of the water base roller. In addition, a pump rotation speed control signal obtained by comparing and calculating the isopropyl alcohol concentration detection signal with a set value is sent to a supply pump for 100% isopropyl alcohol, and the rotation speed of the supply pump is adjusted.
The amount of 100% isopropyl alcohol supplied from the alcohol pan to the dampening water pan is changed to maintain the ink film thickness, water film thickness, and isopropyl alcohol concentration at the set values, so it is not possible to use the same method as in the conventional device described above. After the ink film thickness/water content sensor detects the ink film thickness and water film thickness in a certain divided section, the uncontrolled operation continues until the sensor returns to the same divided section and detects the ink film thickness and water film thickness. The controllability of the ink film thickness and water film thickness can be improved. Furthermore, there is no need to scan the entire axial direction of the first landing side swinging roller with the ink film thickness/moisture content sensor, which not only does not interfere with the printing operation but also has the effect of ensuring the safety of the printing operation.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of an automatic control device for printing density and gradation of a printing press according to the present invention, FIG. 2 is an explanatory diagram showing an isopropyl alcohol supply system, and FIGS.
The figure is an explanatory diagram of the operation, and FIG. 5 is a system diagram showing an automatic control device for printing density and gradation of a conventional printing press. (7)...Ink roller group, (16)...Ink film thickness/moisture content sensor, (19)...Controller,
(51) ...Isopropyl alcohol concentration sensor.

Claims (1)

[Claims] A detection device having an ink film thickness/water content sensor that detects the ink film thickness and water film thickness on the ink roller and an isopropyl alcohol concentration sensor that detects the isopropyl alcohol concentration, and a detection signal from the detection device and a preset a controller that compares and calculates the set value and sends a control signal obtained as a result to the ink source roller and the water source roller to control the rotational speed of the ink source roller and the water source roller; An automatic control device for printing density and gradation of a printing press, characterized in that the ink roller is fixedly supported at any position in the width direction near the ink roller.