JPH07214760A - Device for registering in multicolor press - Google Patents

Abstract

PURPOSE: To adjust a multi-color printing press by forming first and second images having first and second colors from a printed sheet, comparing the first and second images and superposing them in register on the printed sheet. CONSTITUTION: Each camera 28 comprises a fluorescent light source 28 generating a light beam in the visible region of electromagnetic wave having wavelength in the range of 400-700 nm and an infrared light source 40 generating electromagnetic wave in infrared red region directed toward a web 26. These light sources 38, 40 irradiate the sheet 26 from which light and infrared rays are reflected toward each camera 28. For the purpose of registration of a printing press 10, the camera 28 can view four color images corresponding to four colors of ink on a printed sheet 26.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an apparatus for registering in a multicolor printing machine.

[0002]

2. Description of the Related Art Conventionally, there is known a printing machine provided with a plurality of cylinders for printing inks of different colors on a web of a printing machine, and these cylinders separately applying inks of different colors to a paper web one after another. There is. However, it is necessary to maintain registration of the different color inks on the web, or the printer will print a hazy image. In modern registration systems, the press operator examines the printed web and adjusts the press by trial and error as he attempts to register the cylinder on the press. In this way, the paper web is passed through the printing press, the operator adjusts the printing press while operating the printing press at a slow speed, and the operator presses the printing press to make an accurate registration of the printing press. Adjust the machine further.
This approach is extremely time consuming, thus leading to excessive start-up time and more paper consumption during registration. The latest automatic registration system is 0.0
It only registers four-color images within a very close range of exact registration, such as 07 inches, which is not satisfactory. This approach wastes paper as the operator makes final adjustments to the press. In addition, such systems require the goal of eliminating the generation of unwanted or waste printed pages.

[0003]

The main features of the present invention are:
An object of the present invention is to provide an apparatus for registering in a multicolor printing machine.

[0004]

SUMMARY OF THE INVENTION The apparatus of the present invention comprises means for forming a first image of ink having a first color from a printed sheet and at least one having a second color from the printed sheet. Means for forming a second image of one of the other inks and means for comparing the first image and the second image. According to a feature of the invention, the printing press is adjusted in response to said comparison means so that the first and second images of the printing press are registered. According to another feature of the invention, the web of the printing press is stopped when the image is formed. According to yet another feature of the invention, the four color inks are processed to condition the four color printer to register the four color inks on the printed web or sheet of the press. According to yet another feature of the invention, the device of the invention also provides a digitized element of each component,
It has means for separating the four colors by the use of color filters and different light sources, and means for creating outlines drawn from these images and comparing each image.

According to yet another feature of the invention, the image is formed by a suitable camera. According to yet another feature of the invention, a camera determines light intensity at multiple locations on printed sheets. According to yet another feature of the invention, the sheet is illuminated by a light source and an infrared source.
According to yet another feature of the invention, the camera has a filter suitable for measuring at least three colors of ink on a printed sheet. According to yet another feature of the invention, infrared radiation is used to measure black ink.
According to yet another feature of the invention, the camera has a plurality of gray scales at each measured position on the printed sheet to determine the intensity of the image at the plurality of positions. According to yet another feature of the invention, an outline of an image of different colors of ink is formed. According to yet another feature of the invention, outline images are compared to determine a difference between each outline image.

According to yet another feature of the invention, the compared outline images are formed with differently colored inks at a plurality of laterally and longitudinally displaced positions relative to one reference image. According to yet another feature of the invention, outline images of different color inks are compared at different locations to determine a slight lightness difference. According to yet another feature of the invention, the relative position of the slightly lightened outline images represents the best fit of the images. According to yet another feature of the invention, the slight difference in lightness for the different inks compared is utilized to adjust the printing press. According to a further feature of the invention, different images of differently colored inks are superposed at slight lightness differences for registering the printing press. According to yet another feature of the invention, different color images corresponding to different color inks are determined by the camera from the printed sheet. According to yet another feature of the invention, an average intensity of light or an average gray scale value is determined for each image.

According to yet another feature of the invention, images corresponding to different colors of ink are each compared to the average intensity of light associated with that image. According to a feature of the invention, when the intensity of the image at each position is less than the average intensity, the minimum intensity is assigned to this position in the image. According to yet another feature of the invention, when the intensity of the image at each position is greater than the average intensity, the maximum intensity is assigned to this position in the image.
According to yet another feature of the invention, the minimum and maximum intensities for various positions determined by the camera are used to form the outline image. According to another feature of the invention, one of the outline images is superimposed on the other outline image. According to yet another feature of the invention, the difference between the two superposed images is determined. According to a further feature of the invention, the difference between the two images is determined at a plurality of laterally and longitudinally displaced positions of the printed sheet. According to yet another feature of the invention, the outline images are compared at the displaced locations to determine the location of the minimum difference.

According to a feature of the invention, the closest matching of the images at the displaced positions is used to correct the superimposed images of different colors on the printing press and the printed web or sheet. , Register the printing machine. According to yet another feature of the invention, different colored outline images are each checked against a minimum difference at a plurality of positions for registration with all of the different colored inks. To be done. According to another feature of the invention, the device automatically moves the cylinder of the printing press by moving the cylinder horizontally and / or vertically based on the most relevant information calculated from various outline comparisons. To register. According to yet another feature of the invention, the printing press is registered in a simple manner. According to another feature of the invention, the printing press is registered faster. According to yet another feature of the invention, the device more accurately registers the printing press. In accordance with yet another aspect of the invention, the apparatus minimizes print downtime and paper waste while ensuring proper registration of the printing press.

According to a further feature of the invention, the plate distortion of the printing press can be determined and the associated cylinder corrected,
The plate distortion is removed. According to another feature of the invention,
By continuing this method, the device also maintains the correct registration when the press is running. According to another feature of the invention, the device automatically obtains a registration before operating the printing press, and the device keeps the registration while the printing press is in operation, thereby saving time and time. Greatly reduce waste of paper. Other features of the invention will be more fully apparent from the following description of embodiments of the invention and the appended claims.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a multicolor printing machine, generally designated by the reference numeral 10, is shown.
Comprises a device indicated by the reference numeral 12 for obtaining registration. As shown in the figure, the printing machine 10 has blue green (cyan, C), magenta (M, M), and yellow (Y).
And a plurality of printing units 14, 16, 18 and 20 for printing ink having a color such as black (K). Each of the printing units 14-20 is provided with blanket cylinders 22, 24 on either side of a web or sheet 26 passing through the printing machine 10 and is configured to supply different colors of ink to the web 26. . As shown in FIG. 5, a pair of plate cylinders 23, 25
Are respectively associated with blanket cylinders 22, 24, and the plate cylinders 23, 25 are provided with outer plates for transferring ink. In another aspect, the printing press 10 replaces the plate cylinder to form an image directly on the printing cylinder of the printing press 10,
It may have a plurality of printing cylinders. As shown in FIGS. 2 and 3, the adjustment system along the x and y axes may be associated with the seat 26, with the x axis extending longitudinally along the web 26 and the y axis extending along the web 26. Laterally across. This alignment system may be used as a reference during registration of the printing press 10.

As shown in FIG. 1, the device 12 has a pair of cameras 28 facing both sides 30, 32 of a printed web or sheet 26, both cameras having associated hoods 34. As shown, the device 12 may include a plurality of idler rollers 36 disposed adjacent to both sides of the web 26 on either side of the camera 28 to stabilize the web 26 in the area of the camera 28. . Each camera 28 is directed at the web 26 and is approximately 400-70.
An associated light source 28, such as a fluorescent lamp, for generating light in the visible range of electromagnetic waves having a wavelength in the range of 0 nanometers, and an infrared source 40 in the infrared range of electromagnetic waves directed at the web 26. And these radiation sources 3
It is preferable that the sheets 8 and 40 illuminate the sheet 26, and light and infrared rays are reflected from the printed sheet 26 to the respective cameras 28. In this manner, the camera 28 can view four color images corresponding to the four colors of ink on the printed sheet 26 for registering the printing press 10 as described below. In the preferred form, the camera 28 comprises a CCD (charge coupled device) camera for determining the light and infrared intensity at multiple locations on the printed sheet 26 corresponding to the pixels of the camera 28. A plurality of sensors are included in the camera 28. Each of the pixels at the plurality of positions determines a relative light intensity or gray level, which gray scale depends on the light or infrared intensity for each pixel of the camera 28.
In a CCD camera with 56 gray scales, the value 0
It is good to change from 1 to 255. If necessary, as shown in FIG. 3, the signals corresponding to each of the pixels in camera 28 are digitized by a suitable A / D converter 42 and then read only memory (ROM) and random access memory (RAM). A suitable computer 44 having
That is, it may be sent to a central processing unit (CPU), where the data corresponding to gray scale may be stored in the memory of computer 44 for subsequent processing.

The camera 28 preferably comprises a plurality of filters for each of the colors blue-green, magenta and yellow. During use, such three visible colors are viewed and determined by the camera 28 for each of the different colored inks, and, as described above, information corresponding to each of the colored inks is sent to the CPU, where Information is stored. An infrared source 40 is used to illuminate the printed sheet 26 and the corresponding signals determined by the camera are stored in the computer's memory.
Good to be sent to 8. Since it is cheaper to print black in the printing unit 20 than to mix the other three colors to produce black, infrared is used to determine black in the image on the printed sheet 26, and infrared is used. It is used to control the printing machine 10 in printing another black color. In the preferred form, a CPU is utilized to control the printing press 10 to move the printed sheet 26 under the camera 28 very slowly, as shown in FIG. The camera 28 is used to determine when the printed image is placed in the field of view of the camera 28, at which time the CPU causes the sheet 26 printed by the camera 28 to be printed.
The cylinder of the printing press 10 is stopped in order to obtain a clear view of the.

After viewing and storing the data for the different color inks, this information is processed, as described below. First of all, the CPU determines the average gray scale or intensity for each of the different images stored in the CPU's memory, so that four different gray scales corresponding to four different ink colors are obtained. The average occurs. The average grayscale value of the different images is then used as the threshold for different images of different colors. If, at each pixel or location in the data, the grayscale or intensity of the image associated with a given color is less than the average grayscale or intensity of that color, then the pixel is given a minimum or grayscale zero. However, if the intensity or gray scale is greater than the average intensity or gray scale of a given color ink,
The maximum value is given to the pixel or position data. This procedure is repeated for each image formed corresponding to a different color of ink, at each data point or pixel corresponding to a given image. In this way, Kodalys images (Kodal
ith image) is formed corresponding to the recorded image on the sheet 26. Next, in order to form the outline of the image for each color of the ink corresponding to the image printed on the printed sheet 26, the maximum and minimum value data
To process. The outline image is selected for further data processing for the following reasons. That is, first,
This is because accurate registration is widely perceived in terms of high contrast, and secondly, the outline provides important information and discards all other unnecessary information to reduce the S / N ratio, as described below. For a more accurate comparison.

Then, one of the outline images, eg the image corresponding to the blue-green ink, is used as a reference image, and the other outline images, eg magenta, yellow and black images, in this case Sequentially superimpose on the reference image that is blue-green. After separately superimposing the images on the reference image, at each pixel or position, by subtracting the outline value of the first color from each of the second images of the other colors,
Each of the overlay images is compared to the reference image, and the differences are summed to obtain a grayscale or intensity sum for each of the comparison images. Therefore, in order to obtain three different sums for the three comparisons of the image with the turquoise outline image, the CPU is obtained by subtracting the magenta, yellow and black outline images from the turquoise reference image. Determine the total grayscale.
Next, further comparisons for the three colors, magenta, yellow, and black, show different displacements longitudinally along the paper web 26 and laterally across the paper web 26, corresponding to the x and y axes, respectively. That is, it is performed at intervals. In one embodiment, a total distance of 0.2 inches (0.508 cm) along the x-axis is reached and a total distance of 0.1 inches (0.254 cm) is reached along the y-axis in the positive and negative directions. Up to a continuous 0.001 inch (0.0025 cm) displacement along the x-axis and y-position. Therefore, at each interval along the x-axis and the y-axis, images of magenta, yellow and black inks are formed and these additional images are stored in the memory of the CPU (central processing unit). As described above, these outline images are formed corresponding to the inks of different colors at each displacement along the x axis and the y axis. Each outline image along the x-axis and y-axis is, as described above, a reference outline image (cyan) in order to form a different image for different ink colors at each displacement along the x-axis and y-axis. Compared to.

As each ink is compared along the x and y axes, the CPU determines the minimum difference compared along the x and y axes for each of the different inks and the absolute value of this minimum difference. Is retained during this time, showing the closest match between the colored reference image (cyan) and each of the other colored images (red, yellow, black) and the lowest grayscale or intensity determined from the comparison. Comparisons are made to produce the absolute value of the minimum difference value for each of the comparisons between the magenta ink, the yellow ink, and the black ink, which represent the sum. In this way, the best fit of the minimum absolute value shift along the x and y axes to displace the cylinder is determined in order to achieve registration for each of the comparative images of different color inks. . As shown in FIG. 3, the CPU may, for example, modify the cylinders separately by laterally and circumferentially shifting each cylinder separately by appropriate adjustment of the cylinders associated with printed images of different color inks. This data is used to show the best fit for adjusting 10 barrels. In this manner, as controlled by the CPU or computer 44, registration of the overlaid images of different inks is accomplished by adjustment of the printing press 10.

At this time, the printing press 10 is started to print the web 26 on the calibrated printing press 10 once the web 26 has passed the field of view of the camera 28. If desired, the monitoring of the paper web 26 by the camera 28 and the adjustment of the printing press 10 are continued during the movement and printing of the web 26 by the printing press 10. In this way, the apparatus 12 of the present invention automatically registers and maintains all registration of printed images with differently colored inks. This registration can be done without the tedious adjustments conventionally required by the operator of the printing press 10 for approximate registration of the printing press 10. The printing press 10 is more accurately registered according to the present invention and also eliminates the waste of paper that occurs with conventional registration. Another embodiment of the present invention is shown in FIG. 4, where like reference numerals refer to like parts. In this embodiment, the tilt angle Θ is the desired x, y axis and the x ', y'axis rotated by the tilt of one or more plates of the press cylinder for each color of ink on the press 10. Angle .theta., But is shown enlarged in FIG. 4 for clarity. The moved axes x'and y'are determined according to the following relational expressions.

1. x ′ = x (cos (Θ)) − y (sin (Θ)) 2. y ′ = x (sin (Θ)) + y (cos (Θ)) where x and y are the original axes and x ′ and y ′ are the moved axes. The motor-operated cock adjusting device is the printing machine 10.
The adjustment of the printing press 10 is performed according to equations 1 and 2 above to adjust the plate to adjust the tilt of the cylinder for each ink of a different color. The above detailed description is for clarity of understanding, and no unnecessary limitations should be construed from this description, and various modifications will be apparent to those skilled in the art.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an apparatus for performing registration in a multicolor printing machine of the present invention.

FIG. 2 is a schematic view of a printed sheet or web of a printing press.

FIG. 3 is a block diagram of a registration device according to the present invention.

FIG. 4 is a schematic diagram of a printed sheet showing the image on the sheet with skewed angles.

5 is a schematic view of a cylinder for the printing machine of FIG.

Claims (23)

[Claims] 1. A means for forming a first image of ink having a first color from a printed sheet, and a second image of at least one other ink having a second color from the printed sheet. Means for comparing the first image and the second image, and in response to the comparing means, registering the first image and the second image on the printed sheet. An apparatus for registering in a multicolor printing machine, comprising: an adjusting means for adjusting the multicolor printing machine together. 2. The apparatus according to claim 1, wherein the second image forming unit forms a four-color image in a four-color printing machine. 3. The apparatus according to claim 2, wherein the four colors are blue green, magenta, yellow, and black. 4. The apparatus of claim 1, wherein the registration device includes means for illuminating the printed sheet. 5. The apparatus according to claim 4, wherein the illuminating means illuminates the printed sheet separately by light and infrared light. 6. The apparatus of claim 5, wherein said image forming means comprises a video camera, said video camera determining the color of the ink. 7. The apparatus of claim 6, wherein the video camera has a plurality of filters for determining different colors of ink. 8. The apparatus of claim 1, wherein the adjusting means comprises means for changing the position of the cylinders of the multicolor printing press. 9. A means for determining a first outline of an image of a first color ink from a printed sheet, and a second outline of an image of another second color ink from the printed sheet. Means for comparing the first outline of the image of the first color ink with the second outline of the image of the second color ink, and the first means in response to the comparison means. A registration device for a multi-color printing machine, comprising means for adjusting the multi-color printing machine by registering the image of the color ink and the image of the second color ink. 10. The first to printed sheets of a multicolor printing machine
Determining means for determining a first outline image of color ink, determining means for determining a second outline image of another second color ink from the printed sheet of a multicolor printer, and 1st outline image and 2nd on the finished sheet
A comparing means for comparing the first outline image and the second outline image at a plurality of relative positions of the outline image, and between the first outline image and the second outline image in response to the comparing means. Detecting means for detecting the closest position, and responsive to the detecting means, the first outline image and the second outline image are superposed at the closest position to register the multicolor printer. And an adjusting device for adjusting the multi-color printing machine. 11. The locating means forms the closest combination between outline images of a plurality of inks of different colors from the printed sheet, and the adjusting means modifies the multicolor printing machine to produce various combinations. 11. The apparatus of claim 10, wherein registration is made between a plurality of images printed in different colors. 12. The apparatus of claim 10, wherein the camera comprises a camera for viewing an image on a printed sheet. 13. The apparatus according to claim 12, wherein the determining unit determines the light intensities at a plurality of positions on the printed sheet. 14. The apparatus of claim 10 wherein said comparing means includes means for subtracting values associated with said outline image at multiple locations of the image on a printed sheet. 15. The apparatus according to claim 10, wherein the comparison unit compares the first outline image and the second outline image at a plurality of positions of an image on a printed sheet. 16. The comparison unit according to claim 15, wherein the comparison unit compares the first image and the second image at a plurality of positions that are spaced laterally and longitudinally along the printed sheet. apparatus. 17. The apparatus according to claim 10, wherein said adjusting means comprises means for changing the position of a plurality of cylinders in a multicolor printing press. 18. An observing means for observing a printed web in the multi-color printing machine, and a stopping means for stopping the web at a predetermined position in order to look into an image on the web by the observing means. A registration device for a multicolor printing machine, comprising: the observing means and an adjusting means for adjusting the multicolor printing machine in response to the stopping means. 19. An observing means for observing a printed web in the multicolor printing machine, a deciding means for deciding a plate distortion on a cylinder of the multicolor printing machine, and An adjusting device for adjusting the distortion of the plate, and a registration device for a multi-color printing machine. 20. Observing an image on a printed sheet in the multi-color printing machine, and comparing the light intensity of the image with a plurality of inks having different colors at a plurality of positions of the image on the printed sheet. Forming means for forming a proportional signal, determining means for determining an average light intensity of an image observed at a plurality of positions on the printed sheet, and determining light intensity of an image at a plurality of positions Determining means for, comparing the light intensity for a plurality of colors at a plurality of positions on the printed sheet with the average intensity, assigning a minimum intensity to a value of light intensity less than or equal to the average intensity, Comparing means for assigning a maximum intensity to a light intensity value greater than or equal to the average intensity; forming means for forming an outline image for each of the colors in response to the comparing means; Of the two images on the created sheet Comparing means for comparing one of the outline images with the outline reference image at a plurality of laterally and longitudinally displaced positions and for determining the position of the minimum value between the compared images; Adjusting means for adjusting the relative position of the compared images from the minimum value determined between the compared images in response to the determining means; and the printing in response to the adjusting means. A registration device for a multicolor printing machine, comprising: adjusting means for obtaining registration of images of different colors on a sheet and adjusting the multicolor printing machine. 21. The apparatus according to claim 20, wherein the observation means includes a camera. 22. The apparatus according to claim 21, wherein the light intensity comprises a gray scale at a plurality of positions of the camera. 23. Determining means for determining a first outline image of ink of a first color from a printed sheet of said multicolor printer, and a plurality of different second from said printed sheet of said multicolor printer. Determining means for determining a plurality of second outline images of a plurality of inks having colors; a first outline image and a plurality of second outline images at different relative positions of the image on the sheet. Comparing means for comparing, a detecting means for detecting a closest position between the first outline image and the plurality of second outline images in response to the comparing means, In response, the first outline image and the plurality of second outline images are superposed at the positions closest to each other, and the multicolor printing machine is registered to the multicolor printer. Register apparatus of the multi-color printing press and having an adjustment means for adjusting the printing machine.