JP2013010183A - Cooling control device, cooling control method, and printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling control device of a printing machine in which a preset temperature of cooling water is controlled according to a state of printed matter, and which performs enough cooling by the energy of necessary minimum.SOLUTION: In a conveyance path that transports a printing paper 19, pictures of the printing paper 19 before and behind the cooling are taken by a camera 23 provided in front of a cooling roller 171 and by a camera 25 provided after a transport roller 173 that transports the printing paper 19 cooled by the cooling roller 171. The presence of the rubbing of the printing paper 19 before and behind the cooling is detected by a PLC21 based on a photographed image 231 of the camera 23 and a photographed image 251 of the camera 25, and the preset temperature of cooling water is controlled based on the detection results.

Description

  The present invention relates to a cooling control device for controlling a set temperature of cooling water flowing through a cooling roller of a printing press.

  An offset rotary press is known as one that performs printing on printing paper. FIG. 5 is a diagram illustrating a schematic configuration of the offset rotary press 10. The offset rotary press 10 includes a paper feeding unit 11, a printing unit 13, a drying device 15, a cooling unit 17, and the like.

  Printing paper (roll paper) 19 is set in the paper feeding unit 11 and is sent to the printing unit 13 by a conveyance roller.

  The printing unit 13 includes printing units 13a to 13d for each color to be printed (four colors in the example in the figure). Each printing unit 13 has a front surface printing unit 13-1 and a back surface printing unit 13-2, and printing of one color is performed on both the front and back surfaces as the printing paper 19 is conveyed therebetween.

  The front surface printing unit 13-1 and the back surface printing unit 13-2 each have a rotating plate cylinder 131 and a blanket cylinder 133, and ink applied to the plate interposed in the plate cylinder 131 is transferred to the blanket cylinder 133. Then, the ink is transferred to the printing paper 19 and printing is performed. The front surface printing unit 13-1 and the back surface printing unit 13-2 of each printing unit 13 are also provided with rollers or the like (not shown) for supplying ink and fountain solution to the plate cylinder 131.

  The printing paper 19 that has been printed by the printing unit 13 is conveyed to the drying device 15 and subjected to a drying process. The drying process is a process of evaporating the solvent in the ink by blowing hot air on the printing paper 19, but the printing paper 19 immediately after leaving the drying device 15 is in a heated state and the ink is still completely fixed. Not done. If the printing paper 19 in which the ink is not completely fixed is transported by the transport roller as it is, the printing surface comes into contact with the transport roller, and the unfixed ink is rubbed to cause a printing defect. Therefore, the printing paper 19 exiting the drying device 15 is conveyed to the cooling unit 17 in order to fix the ink completely.

  In the cooling unit 17, the printing paper 19 is conveyed on the cooling roller 171, whereby the printing paper 19 is cooled and the ink is fixed. As a result, the surface strength of the ink is improved, and rubbing of printing during subsequent conveyance by the conveyance roller 173 or the like is prevented. Cooling water is passed through the cooling roller 171, and the cooling water is controlled below a certain temperature for cooling the printing paper 19.

  The printing paper 19 on which the fixing of the ink has been completed in the cooling unit 17 is made into a signature by a folding machine (not shown) and then conveyed to a stacker bundler (not shown) to perform back-cutting, protruding alignment, binding, and the like. It is.

Here, several methods have been proposed for the above cooling temperature control method (Patent Document 1, Patent Document 2).
In the method of Patent Document 1, the temperature of the cooling roller is measured by a temperature sensor, the switching valve between the hot water tank and the cold water tank is switched according to the detection output of the temperature sensor, and the temperature of the cooling roller is controlled to a target set value. .
On the other hand, the method of Patent Document 2 aims to reduce power consumption by controlling hot water and cold water passed through rollers of a printing press with a temperature sensor.

JP-A-11-48450 JP 11-254646 A

The cooling capacity required by the cooling roller 171 varies depending on the printing pattern, the temperature of hot air blown onto the printing paper 19 by the drying device 15, and the like. For example, when the amount of ink is large or when the printing paper 19 is thick, the heat capacity increases, and accordingly, a large cooling capacity is required.
Therefore, the temperature of the cooling water in the cooling roller 171 is generally controlled to such a temperature that can cope with the case where the amount of ink is large or the printing paper 19 is thick. However, there are many cases where it is not necessary to cool the printing paper 19 at the above-described temperature, for example, when the amount of ink is not large, and this causes the printing paper 19 to be cooled more than necessary to increase energy loss.

  The present invention has been made in view of the above problems, and provides a cooling control device for a printing press that controls the set temperature of cooling water in accordance with the state of printed matter and performs sufficient cooling with the minimum amount of energy. The purpose is to do.

  A first invention for achieving the above-described object is a cooling control device for controlling a set temperature of cooling water flowing through a cooling roller provided in a printing press, in a transport path for transporting printing paper, A first camera that is provided in front of the cooling roller and shoots the printing paper to be conveyed; and is provided after at least one conveyance roller that conveys the printing paper cooled by the cooling roller in the conveyance path; Based on the second camera that captures the cooled printing paper that is being transported, the photographed image of the first camera, and the photographed image of the second camera, whether or not the printing paper is rubbed before and after cooling is determined. A cooling control device comprising: a control device that detects and controls a set temperature of the cooling water based on a detection result.

It is preferable that the control device raises the set temperature of the cooling water except when the rubbing of the printing paper is detected only in the image captured by the second camera.
In addition, it is preferable that the control device lowers the set temperature of the cooling water when detecting the rubbing of the printing paper only in the photographed image of the second camera.
Further, it is preferable that the control device lowers the set temperature of the cooling water when the set temperature of the cooling water is lowered and then the rubbing of the printing paper is detected in the photographed image of the second camera.
In addition, if the control device does not detect the rubbing of the printing paper in the photographed image of the second camera after lowering the set temperature of the cooling water, the control device sets the set temperature of the cooling water at that time. It is desirable to maintain at temperature.

  A second invention is a cooling control method for controlling a set temperature of cooling water flowing through a cooling roller provided in a printing press, and is provided in front of the cooling roller in a conveyance path for conveying printing paper. A step of photographing the printing paper conveyed by the first camera, and a second camera provided after the at least one conveying roller for conveying the printing paper cooled by the cooling roller in the conveying path. The step of photographing the cooled printing paper to be conveyed, and the control device for rubbing the printing paper before and after cooling based on the photographed image of the first camera and the photographed image of the second camera. Detecting the presence / absence and controlling a set temperature of the cooling water based on the detection result.

It is preferable that the control device raises the set temperature of the cooling water except when the rubbing of the printing paper is detected only in the image captured by the second camera.
In addition, it is preferable that the control device lowers the set temperature of the cooling water when detecting the rubbing of the printing paper only in the photographed image of the second camera.
Further, it is preferable that the control device lowers the set temperature of the cooling water when the set temperature of the cooling water is lowered and then the rubbing of the printing paper is detected in the photographed image of the second camera.
In addition, if the control device does not detect the rubbing of the printing paper in the photographed image of the second camera after lowering the set temperature of the cooling water, the control device sets the set temperature of the cooling water at that time. It is desirable to maintain at temperature.

  A third invention is a printing machine provided with the cooling control device of the first invention.

With such a configuration, the presence or absence of rubbing of the printing paper is detected before and after cooling based on the captured images obtained by photographing the printing paper with the cameras arranged before and after the cooling roller. If there is only rubbing on the printing paper after cooling, the cooling by the cooling roller will be inadequate. Based on this, the temperature of the cooling water will be lowered, and in other cases, cooling will be more than necessary. Because it will be, increase the temperature of the cooling water. As a result, it is possible to cool the printing paper with a necessary minimum energy to a sufficient extent that no printing failure occurs.
Further, after the temperature of the cooling water is lowered, the presence or absence of rubbing of the printing paper is detected again based on the photographed image of the printing paper after cooling. If the cooling water temperature still does not fall sufficiently and rubbing is detected, the cooling water temperature is further lowered, and if the cooling water temperature is sufficiently lowered and rubbing is not detected, the current temperature This printing is performed while maintaining the temperature. As a result, it is possible to perform the actual printing by stabilizing the printing paper at a temperature at which the printing paper can be cooled to a sufficient level that does not cause a printing defect with the minimum necessary energy.

  According to the present invention, it is possible to provide a cooling control device for a printing press that controls the set temperature of cooling water in accordance with the state of printed matter and performs sufficient cooling with the minimum amount of energy.

Schematic configuration diagram of the printing system 1 Schematic configuration diagram of cooling unit 17 A diagram explaining the presence or absence of printing rubbing The flowchart which shows the flow of a process of the cooling control apparatus 20. Schematic configuration diagram showing the configuration of the offset rotary press 10

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a printing system 1 that cools printing paper by the cooling control apparatus of the present invention. The elements already described with reference to FIG. 5 and the like are denoted by the same reference numerals in the drawings and the description thereof is partially omitted.

  The printing system 1 controls the temperature of the cooling water generated by the refrigerator (chiller) 31 and the refrigerator 31 for generating the cooling water supplied to the cooling unit 17 of the offset rotary press 10 in addition to the offset rotary press 10. For example, a cooling control device 20 or the like.

  As shown in FIG. 1, the offset rotary press 10 includes a sheet feeding unit 11, a printing unit 13, a drying device 15, a cooling unit 17, a PLC (Programmable Logic Controller) 18, and the like.

  The PLC 18 outputs a control signal to each device of the offset rotary press 10 based on a signal from each part of the offset rotary press 10 and controls it to execute a printing process.

  As described above, the printing paper 19 set in the paper feeding unit 11 is transported through the printing unit 13 and the drying device 15 by the transport roller or the like under the control of the PLC 18, and during that time, printing and drying processes are performed. The printing paper 19 that has been subjected to the drying process is conveyed to the cooling unit 17, and the printing paper 19 that has passed through the cooling unit 17 is conveyed to a stacker bundler after being folded by a folding machine (not shown).

FIG. 2 is a schematic configuration diagram of the cooling unit 17.
As shown in FIG. 2 and the like, the cooling unit 17 includes a cooling roller 171 and a conveyance roller 173. Cooling water is passed through the cooling roller 171, and the ink on the printing paper 19 is cooled and fixed while the printing paper 19 is conveyed along the cooling roller 171. The printing paper 19 cooled by the cooling roller 171 is conveyed to the outside of the cooling unit 17 by the conveyance roller 173. However, if the ink is fixed, the printing paper 19 is rubbed even if the printing paper 19 is conveyed by the conveyance roller 173 or the like. Will not cause.

  As shown in FIG. 1, the cooling water is cooled and generated by the refrigerator 31, and is sent to the cooling unit 17 through the cooling water pipe 33 in the direction A in the figure, and is supplied to the cooling roller 171. The cooling water that has exited the cooling roller 171 advances through the cooling water pipe 33 in the direction B in the figure, is returned to the refrigerator 31, and is cooled again.

  In FIG. 1, reference numeral 20 denotes a cooling control device, which cools the printing paper 19 sufficiently for fixing the ink and operates the refrigerator 31 with the minimum required energy consumption to set the cooling water set temperature (refrigerator The outlet temperature). The cooling control device 20 includes a camera 23 (first camera), a camera 25 (second camera), a PLC 21 (control device), and the like.

As shown in FIGS. 1 and 2, the camera 23 is installed immediately before entering the cooling roller 171 of the cooling unit 17 in the conveyance path of the printing paper 19 that has come out of the drying device 15. The camera 23 is connected to the PLC 21, and a captured image is sent to the PLC 21.
The camera 25 is installed immediately after the exit of the cooling unit 17 in the transport path. The camera 25 is also connected to the PLC 21 and a captured image is sent to the PLC 21.
These captured images are used for detection of rubbing of the printing paper 19 by the PLC 21.

  In the present embodiment, a pair of cameras 23 and 25 is installed above and below the printing paper 19 and photographs the front and back surfaces of the printing paper 19. This is because there is a possibility that printing rubbing may occur on the front and back surfaces of the printing paper 19 due to the configuration of the conveyance path by the conveyance rollers or the like. When there is a possibility of rubbing only on one surface, such as a configuration of a conveyance path in which only one surface contacts the conveyance roller during transportation, a pair of cameras 23 and 25 that capture the corresponding surface Need only be provided.

When printing is started, the PLC 21 controls the cameras 23 and 25 to acquire a photographed image, determines whether or not cooling water is insufficiently cooled based on the presence or absence of printing rubbing, and determines whether cooling is performed according to the determination result. A water set temperature control signal 27 is sent to the refrigerator 31. A processing program for performing these controls is stored in advance in a memory provided in the PLC 21.
The cooling water set temperature control signal 27 is, for example, an output signal of 4 to 20 mA. By inputting this signal to the control unit of the refrigerator 31, the temperature of the cooling water is appropriately controlled, and the cooling unit 17 ( Cooling of the printing paper 19 by the cooling roller 171) is performed with optimum energy consumption.

FIG. 3 is a diagram for explaining the presence or absence of printing rubbing.
3A is an example of an image 231 photographed by the camera 23, and FIG. 3B is an example of an image 251 photographed by the camera 25.
As shown in FIG. 3A, the printed print image “A” 233 is captured in the image 231. On the other hand, as shown in FIG. 3B, the image 251 is rubbed with a print image “A” 253 and a photograph 255.

As described above, when the image 231 of the camera 23 does not detect the rubbing of the print image 233 and only the image 251 of the camera 25 detects the rubbing of the print image 253, the cooling roller 171 cools the cooling roller 171 to cool it. Scraping of printing occurs when being conveyed, and cooling by the cooling roller 171 is insufficient.
On the other hand, if rubbing is not detected in the printed image 253 from the image 251 of the camera 25, the ink is fixed by cooling by the cooling roller 171. However, there is a possibility that the printing paper 19 is cooled more than necessary.

  Here, the presence / absence of print rubbing may be detected by comparing the image 231 of the camera 23 and the image 251 of the camera 25 with non-defective images, respectively, and based on the difference. The determination of the presence or absence of rubbing of printing is made precisely according to a criterion that is stricter than the criterion for the quality of the printed matter of the finished product.

  Next, the flow of cooling water temperature control by the cooling control device 20 of the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the flow of cooling water temperature control by the cooling control device 20 of the present embodiment.

As shown in the figure, when the main printing is started (S101; Yes), the PLC 21 detects this, and starts photographing the printing paper 19 conveyed by the offset rotary press 10 by the cameras 23 and 25 ( S102). The captured images 231 and 251 are output to the PLC 21. Photographing of the printing paper 19 and output of the photographed image are performed at predetermined intervals.
When the start of actual printing is not detected (S101; No), the start of actual printing is waited.

Note that the start of printing can be detected based on a signal input from the PLC 18 to the PLC 21. For example, when a rotation signal other than 0 of the plate cylinder 131 and a signal indicating the stacker bundler reject OFF are input to the PLC 18, a signal indicating the start of main printing is output from the PLC 18 to the PLC 21.
Rejecting the stacker bundler refers to removing a signature from a conveyance path such as a conveyor that conveys the signature to the stacker bundler. At the time of trial printing etc., reject is ON and the signature is not sent to the stacker bundler. At the time of actual printing, the reject is turned off and the signature is sent to the stacker bundler, so the above signal should be used as an indication of the start of printing. Can do.

  Returning to the description of FIG. The PLC 21 compares the images 231 and 251 transmitted from the cameras 23 and 25 with non-defective images (S103). For a non-defective image, a reference image without rubbing is stored in advance in the memory of the PLC 21 for the target printed matter. The PLC 21 compares the non-defective images with the images 231 and 251 of the cameras 23 and 25, and detects the presence or absence of rubbing.

When the PLC 21 detects that there is no print rubbing in the image 231 of the camera 23 and there is rubbing of printing only in the image 251 of the camera 25 (S104; Yes), the PLC 21 determines that the cooling by the cooling roller 171 is insufficient. A cooling water temperature control signal 27 for lowering the temperature of the cooling water is transmitted to the refrigerator 31 to lower the set temperature when generating the cooling water (S105).
In other cases (S104; No), it is determined that the cooling is not insufficient, and a cooling water temperature control signal 27 for raising the temperature of the cooling water is transmitted to the refrigerator 31 to set the cooling water. The temperature is raised (S109), and the images 231 and 251 transmitted from the cameras 23 and 25 are compared with non-defective images (S103).

When the cooling water temperature setting is lowered in S105, the image 251 photographed by the camera 25 is subsequently compared with a non-defective image (S106), and the presence or absence of rubbing is detected.
When the image 251 has a rubbing of printing (S107; Yes), it is determined that the cooling is still insufficient, and the process returns to S105 to further lower the set temperature.
When the image 251 is not rubbed (S107; No), it is determined that the cooling has been sufficiently performed, the set temperature of the cooling water at that time is maintained until the end of the main printing (S108), and the process is ended. . Here, a new cooling water temperature control signal 27 may not be transmitted, or a signal indicating maintenance of the set temperature of the cooling water may be output to the refrigerator 31 as the cooling water temperature control signal 27.

  For the coolant temperature control signal 27 output in S105, S109, etc., the temperature to be raised or lowered according to the aforementioned determination result is set in advance in correspondence with the output value, etc., and from the PLC 21 in accordance with the determination result. Output.

In the above description, for the sake of simplicity, the processing based on the images 231 and 251 by the pair of cameras 23 and 25 has been described. However, in the present embodiment, two sets of cameras 23 and 25 are arranged above and below the printing paper 19. For example, in S104, when it is detected that at least one of the front and back surfaces of the printing paper 19 is rubbed only in the image 251 of the camera 25, the determination is Yes, and the process proceeds to S105.
In S107, the determination based on the image 251 of the camera 25 is performed for the surface on which the rubbing is detected in the determination in S104. If rubbing is detected on the front and back surfaces in the determination in S104, the process proceeds to S108 if rubbing is not detected on both sides.

  If the image 233 of the camera 23 has been rubbed in S103, the rub has occurred when transporting before the cooling unit 17, so the rubbed part is specified. There is a need to improve. The PLC 21 may notify a manager or the like by transmitting a signal indicating this to an alarm device (not shown).

  Further, in this embodiment, after the cooling roller 171, the printing paper 19 after being transported by several transport rollers 173 is photographed by the camera 25 at the exit of the cooling unit 17, but the camera 25 is In the transport path of the printing paper 19, it may be provided after at least one transport roller 173 after the cooling roller 171.

As described above, in this embodiment, the presence or absence of rubbing of the printing paper 19 is detected before and after cooling based on the captured images 231 and 251 obtained by photographing the printing paper 19 with the cameras 23 and 25 disposed before and after the cooling roller 171. To do. If there is rubbing only on the printing paper 19 after cooling, the cooling by the cooling roller 171 is insufficient, so that the temperature of the cooling water is lowered based on this, and in other cases, it is more than necessary. The temperature of the cooling water is raised. As a result, it is possible to cool the printing paper 19 with a minimum amount of energy to a sufficient extent that no printing failure occurs.
Further, after the cooling water temperature is lowered, the presence or absence of rubbing of the printing paper 19 is detected again based on the image 251 obtained by photographing the printing paper 19 after cooling. If the cooling water temperature still does not fall sufficiently and rubbing is detected, the cooling water temperature is further lowered, and if the cooling water temperature is sufficiently lowered and rubbing is not detected, the current temperature This printing is performed while maintaining the temperature. As a result, it is possible to stabilize the printing paper 19 at a cooling temperature at which the printing paper 19 can be cooled to such an extent that printing defects do not occur with the minimum necessary energy, and to perform the main printing.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.
For example, in the present embodiment, the printing press is the offset rotary press 10. However, the present invention is not limited to this, and any type of printing press can be used as long as the printing paper is cooled by a cooling roller and transported by a transport roller. Absent. For example, a gravure printing machine may be used. In the case of a gravure printing machine, each printing unit that performs printing of one color is provided with a cooling roller that cools the printing paper dried by the drying device and a conveyance roller that conveys the cooled printing paper. By providing a cooling control device similar to the cooling control device 20 described in the embodiment, the same effect can be obtained.

DESCRIPTION OF SYMBOLS 1 ......... Print system 10 ......... Offset rotary press 11 ......... Paper feeding part 13 ......... Printing part 15 ......... Drying device 17 ......... Cooling parts 18, 21 ......... PLC
19 ......... Printing paper 20 ......... Cooling control devices 23, 25 ......... Camera 27 ......... Cooling water temperature control signal 31 ...... Refrigerator (chiller)
33 ... Cooling water piping 171 ... Cooling roller 173 ... Transfer roller

Claims (11)

A cooling control device for controlling a set temperature of cooling water flowing through a cooling roller provided in a printing press,
A first camera that is provided in front of the cooling roller in the transport path for transporting the print paper and photographs the transported print paper;
A second camera configured to take an image of the cooled print paper that is provided and is provided after at least one transport roller that transports the print paper cooled by the cooling roller in the transport path;
Based on the photographed image of the first camera and the photographed image of the second camera, the print paper is detected whether it is rubbed before and after cooling, and the set temperature of the cooling water is controlled based on the detection result. A control device;
A cooling control device comprising:   2. The cooling control device according to claim 1, wherein the control device raises the set temperature of the cooling water except when the rubbing of the printing paper is detected only in a photographed image of the second camera.   3. The cooling control according to claim 1, wherein the control device lowers the set temperature of the cooling water when detecting the rubbing of the printing paper only in the photographed image of the second camera. 4. apparatus.   The control device lowers the set temperature of the cooling water when the set temperature of the cooling water is lowered and then the rubbing of the printing paper is detected in the photographed image of the second camera. Item 4. The cooling control device according to Item 3.   If the control device does not detect the rubbing of the printing paper in the photographed image of the second camera after lowering the set temperature of the cooling water, the control device maintains the set temperature of the cooling water at the current temperature. The cooling control device according to claim 3 or 4, wherein A cooling control method for controlling a set temperature of cooling water passing through a cooling roller provided in a printing press,
Photographing a printing paper to be conveyed by a first camera provided in front of the cooling roller in a conveyance path for conveying the printing paper;
Photographing the cooled printing paper conveyed by a second camera provided after at least one conveyance roller for conveying the printing paper cooled by the cooling roller in the conveyance path;
The control device detects the presence or absence of rubbing of the printing paper before and after cooling based on the photographed image of the first camera and the photographed image of the second camera, and sets the cooling water based on the detection result. Controlling the temperature;
The cooling control method characterized by comprising.   The cooling control method according to claim 6, wherein the control device raises the set temperature of the cooling water except when the rubbing of the printing paper is detected only in a captured image of the second camera.   8. The cooling control according to claim 6, wherein the control device lowers the set temperature of the cooling water when detecting the rubbing of the printing paper only in the photographed image of the second camera. 9. Method.   The control device lowers the set temperature of the cooling water when the set temperature of the cooling water is lowered and then the rubbing of the printing paper is detected in the photographed image of the second camera. Item 9. The cooling control method according to Item 8.   If the control device does not detect the rubbing of the printing paper in the photographed image of the second camera after lowering the set temperature of the cooling water, the control device maintains the set temperature of the cooling water at the current temperature. The cooling control method according to claim 8, wherein the cooling control method is performed.   A printing machine provided with the cooling control device according to any one of claims 1 to 5.

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