JP7473219B2 - Offset web printing system and offset web press - Google Patents

Description

The present invention relates to a printing system for an offset rotary press and an offset rotary press equipped with the printing system.

In offset rotary press printing, dampening water and ink are supplied to the plate cylinder. If too much dampening water is supplied, the ink will become over-emulsified. When the ink becomes over-emulsified, printing smudges occur and waste paper is generated.
The ink emulsification state changes depending on various factors such as the pattern to be printed and the temperature, so in the past, the operator had to judge the ink emulsification state and adjust the supply of dampening water based on their know-how and experience. This caused problems such as inconsistent print quality depending on the operator.
Meanwhile, as disclosed in Japanese Patent Laid-Open No. 2003-233699, a printing system is known that performs machine learning based on measurements of the color tones of print results and the operating conditions of a printing press to control printing.

JP 2005-007769 A

However, the printing system disclosed in Patent Document 1 does not detect the emulsified state of the ink during printing, so there is a time lag between when the ink becomes over-emulsified and when control is executed, and it takes a long time for the ink to reach the appropriate emulsified state, resulting in a lot of wasted paper.

The present invention has been made to solve the above problems, and its purpose is to provide an offset rotary press printing system and offset rotary press that can grasp the ink emulsification state in real time, quickly detect signs of over-emulsification of the ink, and control the dampening water to achieve the appropriate ink emulsification state, thereby making it possible to maintain good print quality from the start to the end of printing, thereby significantly reducing paper waste, and that can be introduced inexpensively and easily into existing offset rotary presses.

The offset rotary press printing system of the present invention is an offset rotary press printing system, which includes at least one printing unit, and the printing unit includes a plate cylinder, a dampening device that supplies dampening water to the plate cylinder, and an inking device that supplies ink to the plate cylinder. The offset rotary press printing system includes a light source that irradiates the surface of the plate cylinder and/or the surface of any roller of the inking device with light, a camera that captures the light reflected from the surface of the roller, and an ink emulsification state detection means that includes a control means that binarizes the image captured by the camera into a range of high and low brightness of the reflected light and calculates the area ratio of the range of high brightness of the reflected light to the total area of the image captured by the camera, and when the area ratio of the range of high brightness of the reflected light calculated by the control means is high, the supply of dampening water from the dampening device is controlled to achieve an appropriate ink emulsification state.

In the offset rotary press printing system of the present invention, the light source can be configured to emit light of a specific wavelength, and the camera can be configured to capture only the reflected light of the specific wavelength.

In the offset rotary press printing system of the present invention, the temperature of the dampening water supplied by the dampening water unit and the temperature of the ink supplied by the inking unit can be kept constant.
With this configuration, the emulsification state of the ink can be accurately determined from the area ratio of the range where the luminance of the reflected light is high.

In the printing system for an offset rotary press of the present invention, the light source may be a high color rendering LED.
With this configuration, changes in the luminance of the reflected light can be detected more clearly, and control based on the detection results can be performed with greater precision.

In the printing system of the offset rotary press of the present invention, the control means can be an offset rotary press printing system that repeatedly calculates and accumulates the area ratio of the range where the reflected light brightness is high during printing execution, machine-learns a control model of the dampening water that brings the ink to an appropriate emulsified state according to the accumulated area ratio, and updates the control model to one that brings the ink to an appropriate emulsified state according to the calculated area ratio.
This configuration makes it possible to always grasp the ink emulsification state stably and to control the dampening water accurately, regardless of the operator's experience or skill.

In the offset rotary press printing system of the present invention, the control means can accumulate at least one of the following information in addition to the area ratio: the operating status of the offset rotary press, detection information of the printing result, temperature, and humidity, and perform machine learning of the control model using the accumulated area ratio and accumulated information other than the area ratio, thereby updating the control model to correspond to the information.
With this configuration, it is possible to grasp the stable emulsified state of the ink and accurately control the dampening water even if at least one of the operating conditions of the offset rotary press, the detection information of the printing results, the temperature, and the humidity changes.

In the offset rotary press printing system of the present invention, the operating conditions of the offset rotary press can include at least one of the amount of dampening water supplied at the start of printing, the amount of ink supplied at the start of printing, information on the image to be printed, the printing speed during printing, the amount of dampening water supplied during printing, and the amount of ink supplied during printing.

In the offset rotary press printing system of the present invention, the detection information of the printing result can be an offset rotary press printing system that includes at least one of the dot shape, dot area ratio, and ink density detected from the printing result.

In the offset rotary press printing system of the present invention, the temperature and humidity information can be an offset rotary press printing system that includes at least one of the following: dampening water temperature at the start of printing, ink temperature at the start of printing, water temperature of the oscillating roller at the start of printing, water temperature of the plate cylinder at the start of printing, temperature inside the factory at the start of printing, humidity inside the factory at the start of printing, dampening water temperature during printing, ink temperature during printing, water temperature of the oscillating roller during printing, water temperature of the plate cylinder during printing, temperature inside the factory during printing, and humidity inside the factory during printing.

In the offset rotary press printing system of the present invention, the control model can be updated on a cloud server independent of the offset rotary press.

In the offset rotary press printing system of the present invention, the control model can be updated by a control device within the offset rotary press.

The offset rotary press printing system of the present invention can be an offset rotary press printing system that uses the updated control model to control the dampening water of the dampening water device.

The offset rotary press of the present invention is an offset rotary press equipped with a printing system according to any one of claims 1 to 12.

According to the offset rotary press printing system of the present invention, the emulsified state of the ink can be grasped in real time, signs of over-emulsification of the ink can be detected early, and the ink can be made to be in an appropriate emulsified state by controlling the dampening water, making it possible to maintain good print quality from the start to the finish of printing, and ultimately significantly reducing paper waste.
Moreover, it can be introduced inexpensively and easily into existing offset rotary presses.
Furthermore, since the emulsified state of the ink is judged based on the area ratio of the range in which the luminance of the reflected light is high, the ink can be made to be in an appropriate emulsified state even if the ink is not in a uniform emulsified state.

1 is an overall front view showing an example of an offset rotary press to which a printing system of the present invention can be applied; FIG. 2 is a configuration diagram of a printing unit. This is an overview of a control system for machine learning. FIG. 11 is a configuration diagram showing a second embodiment of a reflected light detection device. FIG. 11 is a configuration diagram showing a reflected light detection device according to a third embodiment.

An offset rotary press according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is an overall front view showing an example of an offset rotary press to which the printing system of the present invention can be applied.
The offset rotary press 1 in an embodiment of the present invention has a paper feed section 2 that feeds the printed substrate W, a printing section 3 that prints on the printed substrate W transported from the paper feed section 2, and a paper discharge section 4 that discharges the printed substrate W printed in the printing section 3.
The paper feed unit 2 includes a paper feed shaft 91 on which a rolled up substrate W to be printed is attached, and a feed roller 92 on the paper feed shaft 91 that pays out the substrate W to be printed attached to the paper feed shaft 91 and sends it out to the printing unit 3. The feed roller 92 on the paper feed side is rotated by a drive motor (not shown) to pull the substrate W to be printed, and the paper feed shaft 91 is rotated to pay out the rolled substrate W to be printed and send it out towards the printing unit 3.

The paper feed section 2 is not limited to this configuration, and may have a configuration of a paper feed section of a known rotary press, such as a configuration for feeding out paper sheets.
The printing section 3 includes a plurality of printing units 5, which will be described later, and each printing unit 5 performs printing in one color. A drying device 95 is provided on the paper discharge side of each printing unit 5, but this is not essential.
The paper discharge section 4 is provided with a paper discharge side feed roller 93 that sends the printed substrate W printed in the printing section 3 to the paper discharge section 4, and a take-up shaft 94 that takes up the printed substrate W.
The paper discharge section 4 is not limited to this configuration, and may be a configuration of a paper discharge section of a known rotary press, such as a delivery device that discharges the printing substrate W to another processing device, or a sheet stacking device.
A dot detection device 41 and a pattern inspection device 42 for inspecting the printed results are provided between the printing unit 3 and the paper discharge unit 4. The dot detection device 41 and the pattern inspection device 42 are not limited to this configuration, and can be provided at any position downstream of the printing unit 3, such as between a feed roller 93 on the paper discharge side and a take-up shaft 94 that takes up the printed substrate W.

The configuration of the offset rotary press 1 to which the printing system of the present invention can be applied is not limited to this configuration, and can be any configuration, such as providing a processing section between the printing section 3 and the paper discharge section 4 that performs cutting and folding of the printed substrate W.
The printing system of the present invention can be applied regardless of the type of printing substrate W. Therefore, materials used in known offset rotary presses, such as paper and film, can be used as the printing substrate W. In addition, the printing system can be used regardless of the form of the substrate W, such as continuous paper or sheet paper.

The configuration of the printing unit 5 will be described with reference to Fig. 2. Fig. 2 is a diagram showing the configuration of the printing unit.
The printing section 3 is composed of at least one printing unit 5. In the printing unit 5, printing is performed on the printing substrate W with any ink. In the embodiment of Fig. 1, four printing units 5 are provided, each performing printing with yellow (Y), cyan (C), magenta (M), and black (K) ink. All the printing units 5 have the same configuration.
The number of printing units 5 used in the printing system of the present invention is not limited to the embodiment in Fig. 1, and the printing section 3 can be configured with any number of printing units 5, such as only one printing unit that prints with black (K) ink. Furthermore, the inks that can be used are not limited to the above-mentioned yellow (Y), cyan (C), magenta (M), and black (K), and any color ink, such as a spot color, can be used.

2, the printing unit 5 has a plate cylinder 6, a blanket cylinder 7, and an impression cylinder 8. The rotation of the plate cylinder 6, the blanket cylinder 7, and the impression cylinder 8 is controlled by a drive motor (not shown). The substrate W to be printed is transported between the blanket cylinder 7 and the impression cylinder 8.
Printing is performed as follows: Ink and dampening water are supplied to the plate cylinder 6, the ink is transferred from the plate cylinder 6 to the blanket cylinder 7, and the ink is transferred from the blanket cylinder 7 to the printing substrate W, thereby performing printing.
In order to adjust the surface temperature of the plate cylinder 6, cooling water is passed through the inside of the plate cylinder 6. The details of the passage of cooling water will be described later.

A dampening unit 11 for supplying dampening water to the plate cylinder 6 and an inking unit 21 for supplying ink to the plate cylinder 6 are provided adjacent to the plate cylinder 6 .
The dampening water unit 11 includes a dampening water temperature detector 12 , a water fountain 13 , a water fountain roller 14 , a metering roller 15 , and a dampening roller 16 .
The dampening water in the water boat 13 is supplied to the plate cylinder 6 via a water fountain roller 14, a metering roller 15, and a dampening roller 16. The supply of dampening water to the water boat 13 will be described later.
The dampening water temperature detection device 12 detects the temperature of the dampening water in the water tank 13. The temperature of the dampening water measured by the dampening water temperature detection device 12 is used as the dampening water temperature for machine learning, which will be described later.

The inking device 21 includes an ink temperature detection device 22 , an ink fountain 23 , an ink fountain roller 24 , a group of ink supply and distributing rollers 25 , an ink oscillation roller 26 , and an ink roller 27 .
Ink in an ink fountain 23 is supplied to the plate cylinder 6 via an ink fountain roller 24, a group of ink supply and distribution rollers 25, an ink oscillation roller 26, and an ink roller 27. An ink temperature detection device 22 is provided opposite an arbitrary roller in the inking device 21, and measures the temperature of the ink on the roller surface in a non-contact manner. The ink temperature detected by the ink temperature detection device 22 is used as the ink temperature for machine learning, which will be described later.
In order to control the temperature of the ink, cooling water is passed through the inside of the ink oscillator roller 26 to control the surface temperature of the ink oscillator roller 26. The details of the passing of cooling water will be described later.

The flow of cooling water into the inside of the plate cylinder 6, the supply of dampening water into the water boat 13, the flow of cooling water into the inside of the ink oscillation roller 26, and the supply of ink will be described with reference to Fig. 3. Fig. 3 is a schematic diagram of a control system related to machine learning.
In order to adjust the surface temperature of the plate cylinder 6, cooling water is passed through the inside of the plate cylinder 6 from a plate cylinder cooling water circulator 9 shown in FIG.
The plate cylinder cooling water circulation device 9 includes a flow path that supplies cooling water from the plate cylinder cooling water circulation device 9 to the plate cylinder 6, a flow path that circulates cooling water from the plate cylinder 6 to the plate cylinder cooling water circulation device 9, and a plate cylinder cooling water temperature control device 10 that controls the temperature of the circulating cooling water.
The temperature of the cooling water controlled by the plate cylinder cooling water temperature control device 10 is used as the plate cylinder water passing temperature for machine learning, which will be described later.

3, which is provided near the printing unit 5. The dampening water circulating device 17 includes a flow path for supplying dampening water from the dampening water circulating device 17 to the water boat 13, and a flow path for circulating dampening water from the water boat 13 to the dampening water circulating device 17.
The dampening water circulating device 17 is provided with a dampening water cooling device 18 for cooling the dampening water, and is capable of controlling the temperature of the circulating dampening water.
In the printing system of the present invention, the temperature of the dampening water is controlled by a command from the control device 56 shown in FIG. 3, which controls the cooling setting temperature of the dampening water cooling device 18 so that the temperature of the dampening water in the water tank 13 detected by the dampening water temperature detection device 12 becomes the set temperature.

3 provided near the printing unit 5. The ink oscillator roller cooling water circulator 28 includes a flow path for supplying cooling water from the ink oscillator roller cooling water circulator 28 to the ink oscillator roller 26, a flow path for circulating cooling water from the ink oscillator roller 26 to the ink oscillator roller cooling water circulator 28, and an ink oscillator roller cooling water temperature control device 29 for controlling the temperature of the circulating cooling water.
The set temperature of the ink oscillating roller cooling water temperature control device 29 is used as the oscillating roller water passing temperature in the machine learning described later.
In the printing system of the present invention, the ink temperature is controlled by changing the set temperature of the ink oscillation roller cooling water temperature control device 29 in response to a command from the control device 56 .

The supply of dampening water and ink is controlled based on commands from the control device 56 as follows.
The amount of dampening water supplied to the plate cylinder 6 is controlled by controlling the rotational speed of the water fountain roller 14 and the metering roller 15. The water fountain roller 14 and the metering roller 15 are rotated by a drive motor (not shown). In the printing system of the present invention, the rotational speed of the drive motor for the water fountain roller 14 and the metering roller 15 output from the control device 56 is used as the amount of dampening water supplied for machine learning, which will be described later.
The amount of ink supplied to the plate cylinder 6 is controlled by controlling the rotation amount of the ink fountain roller 24. The ink fountain roller 24 is rotated by a drive motor (not shown). In the printing system of the present invention, the rotation amount of the drive motor of the ink fountain roller 24 output from the control device 56 is used as the ink supply amount for machine learning, which will be described later.

At the start of printing, the ink supply amount is initially set according to the image area ratio of the image to be printed as follows.
A number of ink keys (not shown) are arranged in parallel across the width of the ink fountain roller 24 shown in FIG. 2, and the amount of ink dispensed (ink supply amount) across the width of the ink fountain roller 24 is determined by the gap between each ink key and the ink fountain roller 24, i.e., the opening degree of the ink key.
The image area ratio is data converted from the data of the printing plate set on the plate cylinder 6, and represents the area of the image within an area of the width equal to the width of the ink key x the height of the printing plate (the height of the product).
The control device 56 determines the image area ratio for each ink key width in the width direction of the plate from the inputted printing plate data, and adjusts the opening of each ink key based on the determined image area ratio to initially set the ink supply amount.

The printing system of the present invention is provided with an ink emulsification state detection means for detecting the emulsification state of the ink by measuring the brightness of the light reflected from the surface of the plate cylinder 6 and/or the surface of the ink supply roller.
The ink emulsification state detecting means comprises a reflected light detecting device 31 for detecting reflected light from the surface of the plate cylinder 6 of each printing unit 5 as shown in FIG. 1, and a control device 56 as shown in FIG.
The structure of the reflected light detection device 31 for detecting the reflected light 72 from the surface of the plate cylinder 6 will be described below with reference to FIG.
In order to detect reflected light 72 from the surface of the plate cylinder 6, a reflected light detection device 31 is provided near the plate cylinder 6. The reflected light detection device 31 has a light source 32 and a camera 33.
A light such as an LED can be used as the light source 32. In particular, a high color rendering LED can be used as a suitable light source. A high color rendering LED has high color reproducibility and is generally used as a light source for printing equipment and the like.

When a high color rendering LED is used as the light source 32, the change in luminance of the reflected light 72 can be detected more clearly, and therefore control based on the detection result can be performed with higher accuracy.
The camera 33 may be a wide-angle camera capable of capturing an image of the entire width of the plate cylinder 6 (the direction parallel to the rotation axis), or a camera capable of capturing an image of any part of the plate cylinder 6. In addition, in the case of a camera that cannot capture an image of the entire width of the plate cylinder 6, multiple cameras may be provided in the width direction of the plate cylinder 6, and the multiple images captured may be combined to obtain the same results as with a wide-angle camera.
The light source 32 and the camera 33 are configured so that their positions and angles can be adjusted, and they can be adjusted to positions where the reflected light 72 can be easily detected.
As shown by the dashed arrow in Fig. 2, light source 32 irradiates light 71 toward plate cylinder 6, and camera 33 captures reflected light 72 from the surface of plate cylinder 6 as shown by the dashed arrow in Fig. 2. In other words, camera 33 captures the area on the surface of plate cylinder 6 irradiated with light 71.

The light source 32 and the camera 33 may be configured as follows.
The light source 32 is configured to emit light of a specific wavelength, and the camera 33 is configured to capture only the reflected light of the specific wavelength emitted by the light source 32 among the light reflected from the surface of the plate cylinder 6 .

3, the detection results of the reflected light detection devices 31 of each printing unit 5, i.e., the images captured by the cameras 33, are output to a control device 56. The control device 56 analyzes the detection results (captured images) to determine the emulsification state of the ink on the surface of the plate cylinder 6. The reflected light detection devices 31 are controlled by the control device 56.
The control device 56 in this embodiment is configured to control the existing offset rotary press 1 and also the machine learning control described below, but is not limited to this configuration. Control can be performed in any configuration, such as controlling the reflected light detection device 31 and analyzing the detected results (captured images) using an independent control device.

The reflected light detection device 31 is controlled and the detection results (captured images) are analyzed as follows.
Depending on the execution of printing, the reflected light detection device 31 is controlled as follows: The light source 32 is always on during printing, and irradiates the plate cylinder 6 with irradiated light 71. The camera 33 photographs the surface of the plate cylinder 6 during printing in order to detect the luminance of the reflected light 72 relative to the irradiated irradiated light 71, i.e., the luminance of the surface of the plate cylinder 6.
The control device 56 receives the images captured by the camera 33 at regular intervals, for example, every several rotations of the plate cylinder 6, and analyzes the captured images.
The photographing range of the camera 33 may be such that it includes the entire width of the plate cylinder 6 , or it may be such that it photographs any part of the plate cylinder 6 .
Furthermore, the camera 33 captures images at any timing relative to the rotation of the plate cylinder 6 that allows the image to capture the portion of the printing plate attached to the plate cylinder 6. Portions of the captured image other than the plate cylinder 6 are excluded by the control device 56. The range to be excluded is set arbitrarily according to the size of the plate cylinder 6 and the mounting position of the camera 33.
The present invention can be implemented even when the printing plate is only partially attached to the plate cylinder 6, since the photograph can be taken at any time when the portion of the printing plate attached to the plate cylinder 6 can be photographed.

Since the emulsified state of the ink on the surface of the plate cylinder 6 is not uniform across the width and circumference, the brightness of the reflected light 72 from the surface of the plate cylinder 6 is not uniform across the width and circumference, but has high and low areas. One of the reasons for this is thought to be that the dampening water is not supplied uniformly to the surface of the plate cylinder 6.
For this reason, the image captured by the camera 33 does not have a uniform brightness across the entire screen, but has bright and dark areas, and the bright areas are areas where the reflected light 72 has a high brightness, while the dark areas are areas where the reflected light 72 has a low brightness.
Therefore, the control device 56 binarizes the received captured image of the camera 33 based on whether or not the luminance of the reflected light 72 is higher than a reference value. That is, a distinction is made between a portion where the luminance of the reflected light 72 is higher than a reference value (bright portion) and a portion where the luminance of the reflected light 72 is lower than the reference value (dark portion). The criterion for determining whether the luminance of the reflected light 72 is high is a luminance reference value set by machine learning, which will be described later, and a portion equal to or higher than the reference value is determined as a high portion, and a portion equal to or lower than the reference value is determined as a low portion.

Furthermore, the control device 56 calculates the total area of the image captured by the camera 33, and adds up the areas of the parts where the brightness of the reflected light 72 is determined to be high to determine the area of the range where the brightness of the reflected light 72 is high, and calculates the area ratio of the range where the brightness of the reflected light 72 is determined to be high to the total area of the image captured by the camera 33.
If the calculated area ratio is higher than the set value, it is determined that the amount of dampening water supplied is too much, and control is performed to reduce the amount of water supplied to prevent over-emulsification. In other words, if the amount of dampening water supplied is large, there are many bright areas on the surface of the plate cylinder 6, and the area of the range where the brightness of the reflected light 72 is determined to be high increases. The set area ratio value is set by machine learning based on detection information of the printing result, which will be described later. The dampening water (control of the amount of water supplied) is controlled by the control device 56 by controlling the rotation amount of the water fountain roller 14 and the metering roller 15.
When the amount of dampening water supplied is reduced, the number of bright areas on the surface of the plate cylinder 6 decreases, the area of the range in which the brightness of the reflected light 72 is determined to be high decreases, and the area ratio becomes a value below the set area ratio, thereby preventing over-emulsification of the ink on the surface of the plate cylinder 6 and achieving an appropriate ink emulsification state.

Therefore, by measuring the brightness of the reflected light 72 from the surface of the plate cylinder 6, the emulsified state of the ink can be grasped in real time.
This makes it possible to detect early signs of over-emulsification of the ink, and by controlling the dampening water accordingly, it is possible to quickly bring the ink to an appropriate emulsified state that does not cause print smears due to over-emulsification, making it possible to maintain good print quality from the start to the end of printing, and ultimately leading to a significant reduction in paper waste.
Furthermore, since the emulsified state of the ink is judged based on the area ratio in the range where the brightness of the reflected light 72 is high, the ink can be made to be in an appropriate emulsified state even if the ink emulsified state on the surface of the plate cylinder 6 is not uniform.
Furthermore, since it is only necessary to provide the reflected light detection device 31 and the control device 56, it can be introduced inexpensively and easily into existing offset rotary presses, making it possible to grasp and accurately control the ink emulsification state not only in newly developed offset rotary presses, but also in existing offset rotary presses that are already in operation.

3, the control device 56 communicates with a cloud server 51. The cloud server 51 is provided independently of the offset web press 1, and executes machine learning, which will be described later.
That is, the control means of this embodiment is composed of the control device 56 and the cloud server 51, and the machine learning processing described below can be shared between the control device 56 and the cloud server 51 in an arbitrary manner.
In the printing system of the embodiment, the calculation of the area ratio of the range where the brightness of reflected light 72 from the surface of the plate cylinder 6 is determined to be high during printing is repeatedly performed, and the control device 56 or cloud server 51 accumulates the calculated area ratio data, judges the ink emulsification state based on the accumulated area ratio, and machine-learns a control model for dampening water that will result in an appropriate ink emulsification state.
Then, the control device 56 or cloud server 51 uses the results of the machine learning to update the dampening water control model to a control model that provides the optimal supply of dampening water to achieve the appropriate ink emulsification state in accordance with the area ratio calculation result, and outputs the updated model.
Therefore, by using machine learning, it is possible to consistently grasp the ink emulsification state and accurately control the dampening water, regardless of the operator's experience or skill.
It is also possible to control the dampening water each time the area ratio is calculated without machine learning, thereby achieving an appropriate ink emulsification state.

In the embodiment shown in Figure 2, a reflected light detection device 31 is provided opposite the plate cylinder 6 and the brightness of reflected light 72 from the surface of the plate cylinder 6 is measured, thereby showing the case where the object for detecting the emulsified state of the ink is the plate cylinder 6. However, in the present invention, the object for detecting the emulsified state of the ink is not limited to the plate cylinder 6.
For example, as shown in FIG. 4, a reflected light detection device 31 may be provided opposite the ink roller 27 to measure the brightness of reflected light 72 from the surface of the ink roller 27, thereby detecting the emulsification state of the ink on the ink roller 27.
Also, as shown in FIG. 5, a reflected light detection device 31 may be provided opposite the ink oscillating roller 26 to measure the brightness of the reflected light 72 from the surface of the ink oscillating roller 26, so that the ink emulsification state is detected from the ink oscillating roller 26.

In other words, the printing system of the present invention can be implemented with a configuration that measures the brightness of reflected light 72 from the surface of any roller that supplies ink to the plate cylinder 6, such as the ink roller 27 or the ink oscillator roller 26, not limited to the plate cylinder 6.
Furthermore, the measurement of the brightness of the reflected light 72 is not limited to one location, and a plurality of reflected light detection devices 31 may be provided within one printing unit 5. For example, in addition to detecting the reflected light 72 from the surface of the plate cylinder 6, a further reflected light detection device 31 may be provided that detects the reflected light 72 from the surface of the ink roller 27.

As shown in Fig. 3, the control device 56 detects the following data as data for controlling the emulsified state of the ink, in addition to the area ratio of the high brightness range of the reflected light 72 described above, and controls the machine learning described below. Fig. 3 is a schematic diagram of a control system related to machine learning, and shows the control device 56 and targets that send and receive data related to the printing system of the present invention.
The control device 56 acquires information on the operating status of the offset rotary press 1, such as the amount of dampening water supplied at the start of printing, the amount of ink supplied at the start of printing, and information on the image to be printed.
Furthermore, during printing, the printing speed (the rotation speed of the plate cylinder 6), the amount of dampening water supplied during printing, and the amount of ink supplied during printing are constantly obtained.

In order to check the emulsified state of the ink from the print result, the control device 56 acquires detection information of the print result in the following manner.
The halftone dot detector 41, installed between the printing unit 3 and the paper discharge unit 4, photographs the printed substrate W after printing and detects the halftone dot shape and dot area ratio of the printed result. If the ink emulsification state is not appropriate, the halftone dot shape will deteriorate and the dot area ratio will change. The halftone dot shape and dot area ratio are detected at any time during printing and transmitted to the control device 56.
The control device 56 can analyze whether the changes in the dot shape and dot area ratio have changed from the appropriate state and determine whether the emulsification state of the ink is appropriate. The criteria for determining whether the changes in the dot shape and dot area ratio are appropriate or not are determined based on machine learning, which will be described later.
If the control device 56 determines that the emulsified state of the ink is not appropriate, the control model for the dampening water is changed taking into consideration the area ratio of the range in which the luminance of the reflected light 72 is high, as described above.

In order to confirm the ink density from the print result, the control device 56 acquires detection information of the print result in the following manner.
The image inspection device 42 installed between the printing unit 3 and the paper discharge unit 4 photographs the printed image and detects the ink density. If too much dampening water is supplied and the ink is over-emulsified, the ink density will become thinner. The ink density is detected at any time during printing and sent to the control device 56.
The control device 56 can analyze whether the ink concentration has changed from the appropriate state and determine whether the emulsified state of the ink is appropriate. The criteria for determining whether the ink concentration is appropriate or not are determined based on machine learning, which will be described later.
If the ink concentration is not appropriate, the ink supply amount is controlled by the inking device 21 .

It is known that in printing with an offset rotary press, the state of the ink is affected by the temperature and humidity of the offset rotary press 1. For this reason, in order to accurately determine the emulsification state of the ink from the area ratio in the range where the brightness of the reflected light 72 described above is high, it is necessary to keep the temperatures of the dampening water and the ink constant.
Therefore, the control device 56 detects the following temperature and humidity information for the offset rotary press 1: the dampening water temperature at the start of printing, the ink temperature at the start of printing, the water temperature of the oscillating roller at the start of printing, the water temperature of the plate cylinder at the start of printing, the temperature inside the factory at the start of printing, and the humidity inside the factory at the start of printing.

During printing, the dampening water temperature during printing, the ink temperature during printing, the water passing through the rocking roller temperature during printing, the water passing through the plate cylinder temperature during printing, the temperature inside the factory during printing, and the humidity inside the factory during printing are detected at all times.
The temperature and humidity in the factory can be measured by a known thermometer and hygrometer (not shown). The thermometer and hygrometer can be installed at any position near the offset web press 1, such as on the upper side of the printing unit 5.
The control device 56 controls the dampening water and ink temperatures to be constant based on the detected temperature and humidity. For example, if the temperature detected by the dampening water temperature detection device 12 is different from a constant temperature, the dampening water temperature is controlled by the dampening water cooling device 18 to keep the temperature constant. If the temperature detected by the ink temperature detection device 22 is different from a constant temperature, the ink oscillating roller cooling water temperature control device 29 controls the cooling water temperature to keep the temperature constant.

Next, control related to machine learning will be described.
In the printing system of the present invention, the control device 56 acquires, in addition to the area ratio of the range in which the brightness of the reflected light 72 is high, data on the amount of dampening water supplied at the start of printing, the amount of ink supplied at the start of printing, information on the image to be printed, the printing speed during printing, the amount of dampening water supplied during printing, and the amount of ink supplied during printing, as operating conditions of the offset rotary press 1, data on the halftone dot shape, halftone dot area ratio, and ink concentration detected from the print results as detection information of the print result of the offset rotary press, data on the dampening water temperature at the start of printing, the ink temperature at the start of printing, the water flow temperature of the oscillating roller at the start of printing, the water flow temperature of the plate cylinder at the start of printing, the temperature in the factory at the start of printing, the humidity in the factory at the start of printing, the dampening water temperature during printing, the ink temperature during printing, the water flow temperature of the oscillating roller during printing, the water flow temperature of the plate cylinder during printing, the temperature in the factory during printing, and the humidity in the factory during printing, and transmits this data to the cloud server 51 via the Internet.

The cloud server 51 accumulates this data and performs machine learning. As a result of the machine learning, the cloud server 51 creates and updates a control model that outputs optimal control of dampening water and optimal control of ink to achieve a proper ink emulsification state, according to the received data.
For example, based on the control model output from the cloud server 51 and updated, the control device 56 adjusts the amount and timing of dampening water supply by controlling the rotation speed of the water source roller 14 and the metering roller 15, thereby controlling so that the emulsified state of the ink is maintained at an optimum level.
In addition to the above, the amount of ink supplied and the timing of supply may be adjusted by controlling the amount of rotation of the ink fountain roller 24 .

The dampening water temperature and the ink temperature are controlled to be constant by controlling the dampening water cooling device 18 to control the temperature of the dampening water in the water boat 13 and by controlling the ink temperature by the ink oscillating roller cooling water temperature control device 29.
The control may be performed by implementing all of these, or by selecting and controlling any one of them.
In addition, the control may be performed automatically by the control device 56 in response to the output from the cloud server 51, or the output from the cloud server 51 may be notified to an operator, who may then perform the control.
Therefore, even if the operating conditions, printing results, temperature, or humidity of the offset rotary press 1 change, it is possible to always achieve a stable ink emulsification state and accurate control to maintain the ink emulsification state appropriately, regardless of the operator's experience or skill.

The system of the present invention may be controlled by edge AI without using the cloud server 51. As an example of control by edge AI, machine learning that was performed by the cloud server 51 is performed by the control device 56. The control device 56 uses the detected data to create and update a control model within the control device 56. The control device 56 uses the created control model to control the dampening water and ink.
In the case of control using edge AI, there is no need to send and receive data to the cloud server 51 compared to when using the cloud server 51, so communication delays can be avoided and processing can be sped up.

The system of the present invention can also perform control using a trained control model created by machine learning using the cloud server 51 or machine learning using edge AI.
The control device 56 can also apply the data detected by the control device 56 to a control model without performing machine learning, and control the dampening water and ink according to the output results.
When a trained control model is used, implementation is possible even if the processing capacity of the control device 56 is low.

1...offset rotary press, 2...paper feed section, 3...printing section, 4...paper discharge section, 5...printing unit, 6...plate cylinder, 7...blanket cylinder, 8...impression cylinder, 11...damping unit, 13...water tub, 14...water fountain roller, 21...inking unit, 26...ink oscillation roller, 27...ink roller, 31...reflected light detection device, 32...light source, 33...camera, 41...halftone dot detection device, 42...image inspection device, 51...cloud server, 56...control device, 71...irradiated light, 72...reflected light.

Claims (13)

A printing system for a web offset press, comprising:
The offset rotary press includes at least one printing unit,
the printing unit includes a plate cylinder, a dampening device that supplies dampening water to the plate cylinder, and an inking device that supplies ink to the plate cylinder;
an ink emulsification state detection means including a light source which irradiates light onto the surface of said plate cylinder and/or the surface of any one of the rollers of said inking unit, a camera which photographs the light reflected from the surface of said roller, and a control means which binarizes the image photographed by said camera into a range of high and low luminance of the reflected light and calculates the area ratio of the range of high luminance of the reflected light to the entire area of the image photographed by said camera,
An offset rotary press printing system characterized in that, when the area ratio of the range in which the reflected light brightness is high calculated by the control means is high, the supply of dampening water from the dampening water device is controlled to achieve an appropriate ink emulsification state. 2. The printing system for a rotary offset press according to claim 1,
A printing system for an offset rotary press, wherein the light source emits light of a specific wavelength, and the camera captures only the reflected light of the specific wavelength. 3. The printing system for an offset rotary press according to claim 1,
A printing system for an offset rotary press, in which the temperature of the dampening water supplied by the dampening water unit and the temperature of the ink supplied by the inking unit are kept constant. In the printing system for an offset rotary press according to any one of claims 1 to 3,
A printing system for an offset rotary press, wherein the light source is a high color rendering LED. In the printing system for an offset rotary press according to any one of claims 1 to 4,
The control means of the offset rotary press printing system repeatedly calculates and accumulates the area ratio of the range where the reflected light brightness is high during printing, learns by machine learning a control model of dampening water that brings the ink to an appropriate emulsified state according to the accumulated area ratio, and updates the control model to one that brings the ink to an appropriate emulsified state according to the calculated area ratio. 6. The offset rotary press printing system according to claim 5,
The control means accumulates, in addition to the area ratio, at least one of the following information: the operating status of the offset rotary press, detection information of the printing result, temperature, and humidity, and performs machine learning on the control model using the accumulated area ratio and accumulated information other than the area ratio, thereby updating the control model to correspond to the information. 7. The printing system for a rotary offset press according to claim 6,
An offset rotary press printing system, wherein the operating conditions of the offset rotary press include at least one of the amount of dampening water supplied at the start of printing, the amount of ink supplied at the start of printing, information on the image to be printed, the printing speed during printing, the amount of dampening water supplied during printing, and the amount of ink supplied during printing. 8. The printing system for an offset rotary press according to claim 6,
A printing system for an offset rotary press, wherein the detection information of the print result includes at least one of a dot shape, a dot area ratio, and an ink density detected from the print result. In the printing system for an offset rotary press according to any one of claims 6 to 8,
An offset rotary press printing system, wherein the temperature and humidity information includes at least one of the following: dampening water temperature at the start of printing; ink temperature at the start of printing; water flow temperature of the oscillating roller at the start of printing; water flow temperature of the plate cylinder at the start of printing; temperature inside the factory at the start of printing; humidity inside the factory at the start of printing; dampening water temperature during printing; ink temperature during printing; water flow temperature of the oscillating roller during printing; water flow temperature of the plate cylinder during printing; temperature inside the factory during printing; and humidity inside the factory during printing. In the printing system for an offset rotary press according to any one of claims 5 to 9,
The printing system of the offset rotary press, in which the control model is updated on a cloud server that is independent of the offset rotary press. In the printing system for an offset rotary press according to any one of claims 5 to 9,
A printing system for an offset rotary press, wherein the control model is updated by a control device in the offset rotary press. In the printing system for an offset rotary press according to any one of claims 5 to 9,
A printing system for an offset web press, which uses the updated control model to control dampening water in the dampening water unit. An offset rotary press equipped with a printing system according to any one of claims 1 to 12.

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