JP2008173888A - Roller nip management device and roller nip management method - Google Patents

Abstract

Compared to a method of measuring a nip width from a nip trace transferred to paper or the like and a method of automatically adjusting a nip width based on a pressure between a pair of rollers, the adjustment of the nip width is simple and accurate. A roller nip management apparatus and a roller nip management method that can be performed well are provided.
The side surfaces of two rollers (10, 12) are imaged. The nip width between the two rollers 10 and 12 is calculated based on the captured images of the side surfaces of the two rollers 10 and 12. The calculated actual nip width is compared with a preset nip width, and at least one of the rollers 12 is moved so that the calculated nip width matches the set nip width.
[Selection] Figure 1

Description

  The present invention relates to a roller nip management device and a roller nip management method for adjusting a nip width between two opposing rollers in a printing press, and more particularly, a roller nip management device and a roller nip capable of easily and accurately adjusting a nip width. It relates to the management method.

  Many rollers are used in an inking device in a printing machine such as a relief printing machine or an offset printing machine. An example of the configuration of the inking device in the offset printing machine is shown in FIG. In FIG. 5, the ink in the ink fountain 70 is supplied to the plate surface of the plate cylinder 60 via the ink roller group 72. The ink film patterned on the plate surface is transferred to the paper surface of the printing paper W sandwiched between the plate cylinder 60 and the impression cylinder 62, and printing is thereby performed.

  As shown in FIG. 5, the ink roller group 72 has a large number of rollers. This is because the characteristic of ink that is difficult to flow in the ink fountain 70 is changed to a characteristic that is easy to flow and is suitable for supply to the printing plate. Another reason is that the ink film is uniformly spread to have a predetermined thickness, and the ink supply to the printing plate is equalized over the entire surface (top and bottom, left and right direction). In the ink roller group 72 of FIG. 5, a single round roller as indicated by reference numeral 74 is a metal roller, and a double round roller as indicated by reference numeral 76 is a rubber roller.

  Each of the rollers of the ink roller group 72 as described above is preferably in contact with the two opposing rollers uniformly at an appropriate nip pressure without unevenness in the axial direction of the rollers. Here, the nip pressure is a pressure applied to the contact surface of the roller. If the nip pressure is uneven on the left and right, the ink is unevenly transferred, which greatly affects the quality of the printed matter, such as uneven density on the surface of the printing paper and ink scattering due to the ink remaining on the rollers. For this reason, management of the nip pressure is very important for printing.

  At the printing site, the nip pressure as described above is managed by the width at the contact surface between a pair of opposed rollers. This width is called the nip width. In FIG. 6, a nip portion N is formed between a pair of rollers extending substantially in parallel, and a symbol w in FIG. 6 indicates a nip width.

  The adjustment of the nip width is performed by the following method. That is, first, ink is attached to one of the pair of rollers to be adjusted for nip width, and the printing press is stopped after confirming that the ink has been applied to the roller contact portion. Thereafter, the pair of rollers are each rotated slowly, and the printing press is stopped after visually confirming that a nip mark appears on the other roller. Thereafter, the nip trace on the other roller is transferred to the paper, and the nip width is measured from the transferred trace. Then, the nip width is adjusted by moving the bearing portion of at least one roller so as to obtain an appropriate nip width. At that time, in order to balance the nip in the printing direction between the rollers, the nip widths at the operation side and the driving side are measured, and it is confirmed that these nip widths are approximately the same. Such a series of operations is repeated until an appropriate nip width is obtained.

  However, the conventional method for adjusting the nip width as described above has the following problems. That is, it takes time to measure and adjust the nip width, and an operator's experience is required to adjust the nip width to an appropriate value. Another problem is that the trace of the nip width transferred to the paper changes depending on the amount of ink film thickness on the roller, and an error is likely to occur, and the amount of ink film thickness changes due to temperature change. It is mentioned that the nip width cannot be measured with accuracy.

  In order to solve such a problem related to the adjustment of the nip width, a printing unit is disclosed which has a function of detecting the nip width by a CCD sensor and determining an angle at an easily measurable part (for example, see Patent Document 1). . Such an apparatus has an advantage that the nip width can be easily measured, and even an operator with little experience can easily measure the nip width. However, even in a printing unit as shown in Patent Document 1, the method for adjusting the trace of the nip width is the same as the conventional method. For this reason, the trace of the nip width changes depending on the amount of ink film thickness on the roller, and an error is likely to occur, and the ink film thickness amount changes due to a temperature change, so that the nip width cannot be measured with high accuracy. The above problems are difficult to solve.

  As another method, an apparatus is disclosed in which a pressure sensor is attached to a roller and the nip width is automatically adjusted by an actuator (see, for example, Patent Document 2). According to such an apparatus, the time for measuring and adjusting the nip width can be shortened. However, since the shrinkage and curing of the rubber are caused by changes over time in the rubber roller, even if the pressure between the rollers is made uniform, the ink is not always transmitted uniformly. For this reason, the adjustment of the nip width may not be performed with high accuracy.

JP 2002-331645 A JP 2002-137365 A

  The present invention has been made in consideration of such points, and a method of measuring the nip width from the trace of the nip transferred to paper or the like, and automatic adjustment of the nip width based on the pressure between a pair of rollers. It is an object of the present invention to provide a roller nip management device and a roller nip management method capable of easily and accurately adjusting the nip width as compared with the method to be performed.

  A roller nip management device according to the present invention is a roller nip management device for adjusting a nip width between two opposing rollers in a printing press, the actuator for moving at least one of the two rollers, and the 2 An imager that is installed on the side of the two rollers and images the side surfaces of the two rollers, and a nip width between the two rollers based on the image of the side surfaces of the two rollers captured by the imager A nip width calculation unit that calculates the nip width calculated by the nip width calculation unit and a preset set nip width, and the actuator so that the calculated nip width matches the set nip width And an actuator control unit for controlling the motor.

  According to such a roller nip management device, the side surfaces of the two rollers are imaged, the nip width between the two rollers is calculated based on the imaged side surfaces of the two rollers, and the calculated actual nip is calculated. The width is compared with a preset nip width, and at least one of the rollers is moved so that the calculated nip width matches the set nip width. Thus, when adjusting the nip width, compared to a method of measuring the nip width from the nip trace transferred to paper or the like and a method of automatically adjusting the nip width based on the pressure between the pair of rollers. The nip width can be adjusted easily and accurately.

  In the roller nip management device of the present invention, an illuminator is installed at a position on the side of the two rollers and opposite to the imaging device, and the side surfaces of the two rollers are imaged by the imaging device. In this case, it is preferable that the illuminator illuminates the two rollers with light from a direction opposite to the imaging direction, so that the obtained image becomes a black and white image by the backlight. Accordingly, when the nip width calculation unit calculates the nip width between the two rollers, the binarization process is facilitated for the monochrome image.

  The roller nip management device of the present invention further includes a storage unit for storing the set nip width, and images of side surfaces of the two rollers captured by the imaging device, calculated by the nip width calculation unit. It is preferable that a nip width between two rollers or a control amount of the actuator by the actuator control unit is stored in the storage unit.

  In the roller nip management device of the present invention, it is preferable that the movement amount of the roller by the actuator can be manually input to the actuator control unit. As a result, the operator can adjust the nip width between the two nips according to the actual situation visually observed by the operator, based on the calculated nip width, and the nip width can be adjusted more accurately. Adjustments can be made.

  The roller nip management method of the present invention is a roller nip management method for adjusting a nip width between two opposing rollers in a printing press, the step of imaging the side surfaces of the two rollers, and the two imaged The step of calculating the nip width between these two rollers based on the image of the side of the roller is compared with the calculated nip width and a preset set nip width, and the calculated nip width is And a step of moving at least one of the two rollers so as to match a set nip width.

  According to such a roller nip management method, the side surfaces of the two rollers are imaged, the nip width between the two rollers is calculated based on the imaged side surfaces of the two rollers, and the calculated actual nip is calculated. The width is compared with a preset nip width, and at least one of the rollers is moved so that the calculated nip width matches the set nip width. Thus, when adjusting the nip width, compared to a method of measuring the nip width from the nip trace transferred to paper or the like and a method of automatically adjusting the nip width based on the pressure between the pair of rollers. The nip width can be adjusted easily and accurately.

  In the roller nip management method of the present invention, when the side surfaces of the two rollers are imaged, the two rollers are illuminated with light from a direction opposite to the imaging direction, so that the obtained image is black and white by the backlight. An image is preferred. As a result, when calculating the nip width between the two rollers, the binarization process is facilitated for the monochrome image.

  According to the roller nip management device and the roller nip management method of the present invention, when adjusting the nip width, the nip width is determined based on the method of measuring the nip width from the nip trace transferred to paper or the like and the pressure between the pair of rollers. Compared with the method of automatically adjusting the nip width, the nip width can be adjusted easily and accurately.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 to FIG. 4 are diagrams showing an embodiment of a roller nip management device according to the present invention.
Among these, FIG. 1 is a schematic diagram showing an outline of the configuration of the roller nip management device in the present embodiment, and FIG. 2 is an image of the side surfaces of two rollers imaged by the image pickup device of the roller nip management device in FIG. FIG. 3 is a distribution diagram used when calculating the nip width from the image shown in FIG. 2 in the nip width calculator of the roller nip management device of FIG. FIG. 4 is a flowchart showing the operation of the roller nip management device shown in FIG.
The roller nip management device and the roller nip management method in the present embodiment are for adjusting the nip width between two opposing rollers in the printing press.

  As shown in FIG. 1, the roller nip management device according to the present embodiment has one roller 12 of two rollers 10 and 12 facing each other aligned with the axis of the roller 12 extending in the Y-axis direction in FIG. 1, for example. An X-axis actuator 20 that moves in the horizontal direction (X-axis direction) on the orthogonal vertical plane, a Z-axis actuator 22 that moves in the vertical direction (Z-axis direction) on the vertical plane, and these two rollers 10 and 12. And an imager 24 that images the side surfaces of the rollers 10 and 12. Note that one of the two rollers 10 and 12 facing each other is a rubber roller and the other is a metal roller, and a nip portion N is formed between these rollers 10 and 12. Further, an illuminator 26 is installed on the side of the two rollers 10 and 12 on the opposite side of the image pickup device 24. As shown in FIG. 1, the roller nip management device according to the present embodiment includes a nip width calculation unit 30 that calculates the nip width between the two rollers 10 and 12 based on an image captured by the imager 24. The display unit 32 displays the nip width calculated by the nip width calculation unit 30, and the actuator control unit 34 controls the X-axis actuator 20 and the Z-axis actuator 22 based on the nip width calculated by the nip width calculation unit 30. And a storage unit 36 for storing the set nip width. The nip width calculating unit 30, the display unit 32, the actuator control unit 34, and the storage unit 36 constitute a control mechanism 40 of the roller nip management device.

  Hereinafter, each component of such a roller nip management device will be described in detail.

  The X-axis actuator 20 and the Z-axis actuator 22 are configured so that one of the two rollers 10 and 12 facing each other is in the horizontal direction (X-axis direction) and the vertical direction (Z-axis direction) perpendicular to the axis of the roller 12. Direction). Each of these actuators 20 and 22 is communicatively connected to an actuator control unit 34 of the control mechanism 40 and is controlled by the actuator control unit 34.

  The image pickup device 24 is composed of, for example, a CCD camera, and forms a single image by picking up the side surfaces of the rollers 10 and 12 from the side. The illuminator 26 is provided at a position opposite to the image pickup device 24 with respect to the rollers 10 and 12, and illuminates the side surfaces of the rollers 10 and 12 with light. Here, the illuminator 26 illuminates light from a direction opposite to the imaging direction by the imaging device 24. For this reason, as shown in FIG. 2, the rollers 10 and 12 obtained by the imaging device 24 are used. The image on the side surface becomes a black and white image by backlight (that is, the shaded portion in FIG. 2 becomes a shadow). This facilitates the binarization process for the monochrome image. As shown in FIG. 2, the black and white image picked up by the image pickup device 24 is an image in which the nip portion N between the rollers 10 and 12 extends substantially in the horizontal direction.

  The nip width calculation unit 30 calculates the nip width between the two rollers 10 and 12 based on the black and white images of the side surfaces of the two rollers 10 and 12 captured by the imager 24. A specific calculation method of the nip width by the nip width calculation unit 30 will be described with reference to FIGS. For the black and white image shown in FIG. 2, the number of pixels of the white image and the number of pixels of the black image on the horizontal axis are respectively calculated, and a distribution diagram of the pixels of each color image is created. That is, in FIG. 2, the number of pixels of the white image and the number of pixels of the black image are respectively calculated in a region between two two-dot chain lines extending in the lateral direction with a slight interval. Then, while moving the two two-dot chain lines in the vertical direction of FIG. 2, the number of pixels of the white image and the number of pixels of the black image at each position in the vertical direction are respectively calculated, and the white image as shown in FIG. A distribution diagram is created with the number of pixels on the horizontal axis and the number of pixels in the black image on the vertical axis. Here, in the distribution diagram shown in FIG. 3, the portion where the number of pixels of the black image is the smallest (portion indicated by the symbol A in FIG. 3) is a pixel detected at the nip portion N between the rollers 10 and 12. Thereby, the nip width is calculated from the number of pixels of the black image in the portion indicated by the symbol A in FIG. At this time, in order to calculate the nip width from the distribution diagram of FIG. 3, the scale of the image picked up by the image pickup device 24 and the actual scale of each of the rollers 10 and 12 are set in advance, for example, “1 pixel = 0. It is necessary to adjust to “05 mm”. In FIG. 3, since the number of pixels of the black image in the portion indicated by the symbol A is 8, the nip width is 0.4 mm.

  The display unit 32 includes, for example, a touch panel, and displays the nip width calculated by the nip width calculation unit 30. As a result, the operator can confirm the actual nip width on the display unit 32.

  The actuator control unit 34 compares the nip width calculated by the nip width calculation unit 30 with a preset nip width, so that the calculated nip width matches the set nip width. The shaft actuator 22 is controlled. Specifically, the movement amount (control amount) of the roller 12 is instructed to the X-axis actuator 20 and the Z-axis actuator 22. Here, the set nip width is stored in the storage unit 36, and information related to the set nip width is transmitted from the storage unit 36 to the actuator control unit 34. The X-axis actuator 20 and the Z-axis actuator 22 move the roller 12 in the X-axis direction and the Z-axis direction based on the movement amount transmitted from the actuator control unit 34, thereby changing the nip width between the rollers 10 and 12. be able to.

  Further, the storage unit 36 has information on the black and white images of the side surfaces of the two rollers 10 and 12 captured by the imager 24 and information on the nip width between the two rollers 10 and 12 calculated by the nip width calculation unit 30. Alternatively, information on the control amount of the actuators 20 and 22 (that is, the movement amount of the roller 12) by the actuator control unit 34 is sent, and this information is stored. The above-mentioned history stored in the storage unit 36 can be displayed on the display unit 32, and the operator can check the history on the display unit 32.

  Next, the operation of the roller nip management device as described above (roller nip management method) will be described with reference to the flowchart of FIG.

  First, as shown in Step 1 of FIG. 4, the side surfaces of the rollers 10 and 12 are imaged from the side by the imager 24 to form a single image as shown in FIG. 2. At this time, the illuminator 26 illuminates the rollers 10 and 12 with light from a direction opposite to the imaging direction, so that the obtained image becomes a monochrome image by the backlight. At this time, it is preferable that there is no ink on the rollers 10 and 12 (after cleaning the rollers 10 and 12), or the ink film thickness on the rollers 10 and 12 is thin. This is because if the ink film thickness is large, an error may occur in the measurement of the nip width described later.

  Next, as shown in Step 2 of FIG. 4, the nip width calculation unit 30 calculates the nip width based on the captured monochrome image. In calculating the nip width, as described above, a distribution diagram of the number of pixels of the white image and the number of pixels of the black image as shown in FIG. 3 is used.

  Next, as shown in Step 3 of FIG. 4, the actuator controller 34 compares the actual nip width calculated by the nip width calculator 30 with a preset nip width. Here, if there is no difference between these two nip widths, it is confirmed that the actual nip width between the rollers 10 and 12 is a desired value as shown in Step 6, and the operation by the roller nip management device is completed. To do. On the other hand, if there is a difference between the two nip widths described above, the actuator controller 34 calculates the difference between the actual nip width and the set nip width as shown in Step 4, and the roller 12 based on this difference. The respective movement amounts on the X axis and the Z axis are calculated.

  Thereafter, information related to the amount of movement of the roller 12 is transmitted from the actuator control unit 34 to the X-axis actuator 20 and the Z-axis actuator 22. Then, as shown in Step 5 of FIG. 4, the X-axis actuator 20 and the Z-axis actuator 22 respectively move the roller 12 in the X-axis and Z-axis directions based on the information sent from the actuator control unit 34.

  Thereafter, as shown in the flowchart of FIG. 4, the side surfaces of the rollers 10 and 12 are imaged again by the imager 24, and the operations shown in Steps 1 to 5 of FIG. 4 are repeated until the actual nip width and the set nip width coincide with each other. Done.

  As described above, according to the roller nip management apparatus and the roller nip management method of the present embodiment, the side surfaces of the two rollers 10 and 12 are imaged, and two images are obtained based on the captured images of the side surfaces of the two rollers 10 and 12. The nip width between the rollers 10 and 12 is calculated, the calculated actual nip width is compared with a preset nip width, and the roller 12 is adjusted so that the calculated nip width matches the set nip width. It is designed to move. Thus, when adjusting the nip width, compared to a method of measuring the nip width from the nip trace transferred to paper or the like and a method of automatically adjusting the nip width based on the pressure between the pair of rollers. The nip width can be adjusted easily and accurately.

  The roller nip management device according to the present embodiment is not limited to the above-described aspect, and various changes can be made. For example, the movement amount of the roller 12 by each actuator 20, 22 may be manually input to the actuator control unit 34. In this case, the operator can adjust the nip width between the nips 10 and 12 according to the actual situation visually observed by the operator, for example, based on the nip width displayed on the display unit 32. Thus, the nip width can be adjusted with higher accuracy.

  Further, in the roller nip management device, the X-axis actuator and the Z-axis actuator are not limited to those provided only on one of the two opposed rollers 10 and 12, and the two rollers 10 and 12 are not limited. Both may be provided with an X-axis actuator and a Z-axis actuator, respectively. In this case, when adjusting the actual nip width between the two rollers 10 and 12 based on the nip width calculated by the nip width calculating unit 30, not only the roller 12 but also the other roller 10 is moved. Thus, the actual nip width can be adjusted.

It is the schematic which shows the outline of a structure of the roller nip management apparatus in one embodiment of this invention. It is the image of the side surface of two rollers imaged with the imaging device of the roller nip management apparatus of FIG. FIG. 3 is a distribution diagram used when calculating the nip width from the image shown in FIG. 2 in the nip width calculation unit of the roller nip management device of FIG. 1. It is a flowchart which shows the operation | movement in the roller nip management apparatus shown in FIG. It is a figure which shows an example of a structure of the ink apparatus in an offset printing machine. It is a figure for demonstrating the nip width between a pair of nips.

Explanation of symbols

10, 12 Roller 20 X-axis actuator 22 Z-axis actuator 24 Imager 26 Illuminator 30 Nip width calculation unit 32 Display unit 34 Actuator control unit 36 Storage unit 40 Control mechanism 60 Plate cylinder 62 Impression cylinder 70 Ink fountain 72 Ink roller group 74 Metal roller 76 Rubber roller

Claims (6)

A roller nip management device for adjusting the nip width between two opposing rollers in a printing press, comprising:
An actuator for moving at least one of the two rollers;
An imager that is installed on the side of the two rollers and images the side surfaces of the two rollers;
A nip width calculator that calculates the nip width between these two rollers based on the images of the side surfaces of the two rollers captured by the imager;
An actuator controller that compares the nip width calculated by the nip width calculator with a preset nip width, and controls the actuator so that the calculated nip width matches the set nip width;
A roller nip management device comprising: An illuminator is installed on the side of the two rollers on the opposite side of the imager,
When the side surfaces of the two rollers are imaged by the imaging device, the illuminator illuminates the two rollers with light from a direction opposite to the imaging direction, so that an obtained image is black and white by backlighting. 2. The roller nip management device according to claim 1, wherein the roller nip management device is an image. A storage unit for storing the set nip width;
The image of the side surface of the two rollers imaged by the imaging device, the nip width between the two rollers calculated by the nip width calculation unit, or the control amount of the actuator by the actuator control unit is stored in the storage unit. The roller nip management device according to claim 1, wherein the roller nip management device is configured to be configured as described above.   4. The roller nip management device according to claim 1, wherein the movement amount of the roller by the actuator can be manually input to the actuator control unit. 5. . A roller nip management method for adjusting the nip width between two opposing rollers in a printing press, comprising:
Imaging the sides of the two rollers;
Calculating a nip width between the two rollers based on the image of the imaged side surfaces of the two rollers;
Comparing the calculated nip width with a preset nip width, and moving at least one of the two rollers so that the calculated nip width matches the set nip width; ,
A roller nip management method comprising:   2. When imaging the side surfaces of the two rollers, the two rollers are illuminated with light from a direction opposite to the imaging direction, so that the obtained image becomes a black and white image by the backlight. Item 6. The roller nip management method according to Item 5.

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