JP2806502B2 - Printing simulation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention adjusts color separation conditions (various color correction amounts) in color printing of a color original, and substantially inspects a plate (checks separation conditions). More particularly, the present invention relates to a print simulation apparatus that is used in combination with a general color scanner and that is convenient for proofreading. [Prior Art] When performing color printing, a color original is read by a color scanner, and after performing various color corrections on the read image signal, color separation is performed, and a color separation plate is created according to the color separation signal. I have. Then, a printing plate for proof printing is made from the obtained color separation plate, and the printing plate for proof printing is proof printed by a proof printing machine. Determine whether the color separation conditions (color correction amount) of the scanner are appropriate based on the color tone of the proof print. , And proof printing. When a proof print of a preferable color tone is obtained, a working plate is made from the color separation plate, and the final printing is performed by a printing machine (practical machine). By the way, such a proof is quite a lot of time,
In recent years, various printing simulation devices using a color monitor have been developed due to the need for cost and labor, and the finished state of the printed matter can be simulated on the color monitor and the plate can be inspected without performing proof printing. Is possible. In a conventional printing simulation apparatus, an image signal extracted from a color scanner is temporarily written to a memory, and a signal read from the memory is transferred to a color monitor through a color correction circuit identical to a color correction circuit provided in the color scanner. Supply. Then, the finished state of the printed matter is simulated on a color monitor to perform electronic plate inspection, and a color correction circuit is adjusted to determine a preferable color correction amount, that is, a color separation condition. [Problems to be Solved by the Invention] However, in such a print simulation apparatus, since the color separation change condition is determined by a color correction circuit different from the color correction circuit on the color scanner side, a color separation version is used. To create the color separation conditions, the color separation conditions must be manually set in the color correction circuit of the color scanner, which is troublesome and sometimes cannot be set accurately. SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing simulation apparatus having a simple configuration and capable of accurately setting a color separation condition of a color scanner. [Means for Solving the Problems] A print simulation apparatus according to the present invention stores a first frame memory 62 which stores an image signal before color correction in a color scanner and supplies the stored signal to a color correction circuit 22 of the color scanner. A second frame memory 76 for storing image signals after color correction in the color scanner, and a color monitor 86 for displaying the image signals stored in the second frame memory 76. According to the present invention, an image signal read by a color scanner, an image signal before color correction is once written to a first frame memory 62, and a signal read from the first frame memory 62 is read by a color correction circuit of the color scanner. Supply 22. The output signal of the color correction circuit 22 is written to the second frame memory 76, and based on the signal read from the second frame memory 76, while simulating a print image on the screen of the color monitor 86, the color of the color scanner By adjusting the correction amount of the correction circuit 22 and determining the color separation condition, the color separation condition can be set in the color correction circuit 22. Embodiment An embodiment of a printing simulation apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment. The printing simulation device 2 is connected to a color scanner 4. The printing simulation device 2 is disposed below, behind, and the like of the color scanner 4. However, the color monitor 86 and the operation panel 90 are separate, and the color monitor 86 is arranged in a place that is easy to see. The operation panel 90 is arranged near the operation panel of the color scanner 4. As the color scanner 4, a known direct scanner (SG608, Dainippon Screen Mfg. Co., Ltd.) or the like can be used. In the color scanner 4, the color document 12 attached to the reading drum 10 is scanned by the rotation of the reading drum 10 and the movement of the reading head 14, and image information is read.
The reading head 14 includes a photomultiplier as a photoelectric conversion element, and converts an obtained image signal into a beam splitter,
R, G, B by red (R), green (G) and blue (B) filters
As an image signal. The R, G, B image signals output from the read head 14 are subjected to current / voltage conversion by a power / voltage (C / V) converter 16, supplied to a calibration circuit 18, and adjusted in level.
The output signal of the calibration circuit 18 is logarithmically compressed by a logarithmic (LOG) amplifier 20, and then supplied to a color correction circuit 22. The color correction circuit 22 includes a masking circuit 24 and under color removal (UCR).
A circuit 26, a gradation correction circuit 28, a negative / positive conversion circuit (not shown), a dot% display circuit (not shown), etc., perform color correction and correction for printing, that is, color separation conditions. Is a circuit for setting. The masking circuit 24 performs so-called masking correction, and outputs R, G,
The B signal is converted into a yellow (Y), magenta (M), and cyan (C) signal. The under color removal circuit 26 is used for the four basic colors Y,
The Y, M, C signals are converted to Y, M, C, K signals for printing in M, C, K (black). The gradation correction circuit 28 performs gradation correction such as highlight set, shadow set, middle separation, highlight separation, and shadow separation. By appropriately adjusting the correction amount and the correction amount, the color separation plate to be created has a preferable color tone. After correcting and correcting the colors by the color correction circuit 22,
The Y, M, C, and K image signals are log-expanded by an antilogarithmic (LOG ⁻¹ ) amplifier 30 and supplied to a channel (CH) selector 32. The channel selector 32 selects which color signal to output, depending on whether the four color separation films are exposed simultaneously or one color at a time. After the output of the channel selector 32 is converted into a digital signal by an analog / digital (A / D) converter 34, a dot generator 36
Supplied to The dot generator 36 converts the image signal into a dot signal for recording as a dot in consideration of the magnification of the color separation film 42 with respect to the color original 12. The exposure head 38 exposes the color separation film 42 on the recording drum 40 in accordance with the halftone signal whose magnification is controlled. By developing the color separation film 42, a color separation plate is created. The color scanner 4 is connected to the print simulation device 2 at the output terminal of the calibration circuit 18 and the output terminal of the channel selector 32. That is,
The output signal of the calibration circuit 18 (input signal to the logarithmic amplifier 20) and the output signal of the channel selector 32 are supplied to the print simulation device 2, and the signal from the print simulation device 2 is input to the logarithmic amplifier 20. . Alternatively, logarithmic amplifier 20, gradation correction circuit 28
Is supplied to the print simulation apparatus 2,
A signal from the print simulation device 2 may be input to the masking circuit 24. The R, G, B signals from the calibration circuit 18 input to the printing simulation apparatus 2 are converted into an interface (I / F) circuit 56 including a level adjuster 50, an averaging circuit 54, and the like.
Is written to the line memory 60 composed of a semiconductor memory via the A / D converter 58. The level adjuster 50 converts the voltage level of the image signal. In the color scanner 4, the voltage level of the image signal differs depending on the type of the scanner. In the print simulation apparatus 2, since the video signal is 0.7 Vpp, which is a general video signal, a level conversion is required. The averaging circuit 54 is a kind of low-pass filter circuit that averages the input image signal to convert it to a somewhat smooth signal, and controls the signal in accordance with the sampling frequency of the A / D converter 58. The details of the interface circuit 56 are described in detail in Japanese Patent Application No. 61-55514, and a detailed description thereof will be omitted. The line memory 60 is a buffer memory, and the output of the line memory 60 is written to a frame memory 62 also composed of a semiconductor memory. Frame memory 62 is 512 × 512 (pieces)
Each pixel of × 3 (color) is stored in 8 bits (256 density steps). The frame memory 62 can rotate the image 90 ° right and left by exchanging the horizontal address and the vertical address at the time of reading or writing. The output of the frame memory 62 is input to the logarithmic amplifier 20 of the color scanner 4 via the D / A converter 64, and the read head
Similarly to the signal from 14, the signal is supplied to the color correction circuit 22. A single image is read by a color scanner 4 and a drum is read.
It takes about 20 seconds to read at 10 512 rotations, and the color correction circuit 22
Is designed around 200KHz. for that reason,
The input to the frame memory 62 takes about 20 seconds, and the output takes about two seconds to read one image signal from the frame memory 62 in order to match the frequency band of the color correction circuit 22. The output of the line memory 60 is also supplied to the hard disk device 68 via the thinning circuit 66. Hard disk drive 68
Is a cassette type, has a storage capacity of about 20 MB, stores image signals of 18 screens, and stores one of them as a heading screen composed of 16 reduced screens. The thinning circuit 66 reduces the image to 1/16 in order to create this heading screen. Further, the output of the line memory 60 is supplied to the hard disk device 68 as it is. The line memory 60 and the thinning circuit 66 are incorporated in the I / F unit of the hard disk device 68. On the other hand, the Y, M, C, and K signals from the channel selector 32 input to the printing simulation apparatus 2 are also written into the frame memory 76 composed of a semiconductor memory via the interface circuit unit 72 and the A / D conversion unit 74. The interface circuit unit 72 has a level adjuster and an averaging circuit as well as the interface circuit 56, and also has a negative / positive conversion circuit, a thinning circuit, and a cropping circuit. The negative / positive conversion is performed only when the color document 12 is a negative document, and the error in the conversion is within ± 1%. The negative / positive conversion can be selectively performed only on one of the four types of channels, and this selection can be preset. The cropping circuit displays a mask for designating a color separation area in the color document 12 on the screen, and functions by a cropping signal from the color scanner 4. The frame memory 76 stores each pixel of 512 × 512 (pieces) × 4 (color) in 8 bits (256 density levels). The frame memory 76 has an image enlargement function (× 2, × 4), an inversion function (up and down, left and right), a two-image comparison display function, and a non-interlace output function. According to the enlargement function, it is possible to display an area of an enlarged portion and move the area. The display area after the enlargement is also movable. The inversion function is to move the image up and down,
This is the function of mirror inversion for the left and right. The two-image comparison display function is a function of displaying two images side by side using the frame memory 78, and comparing the image before color correction with the image after color correction, and comparing the two images. Is used to unify the color of a specific part (for example, the background).
At this time, left and right scrolling is possible. The two-image comparison image can be stored in the hard disk device 68. The output of the frame memory 76 is supplied to the D / A conversion unit 80. Although not shown, the D / A conversion unit 80 includes a flashing circuit, a dot% display circuit, a two-image comparison display circuit, a white frame display circuit, a color separation display circuit, a gamma correction circuit, a white clip circuit, and a color patch circuit. Image processing of the output of the frame memory 76 for each color component of the printing ink. The flashing circuit flashes pixels at a level higher than the highlight set. This highlight set level is variable for each color. In Y, M, and C, when each pixel level exceeds the highlight set level, flashing is performed in each color, and in three colors, flashing is performed in gray (about 40% of each of the Y, M, and C halftone dots). K requires an on / off switch,
When on, flushing is performed at about 40% of the halftone dots of the K plate. The dot% display circuit displays a movable “+” mark in the screen of the color monitor 86, and measures Y, M, C,
Outputs the DC level of K. The white frame circuit displays a pure white (paper white) frame outside the printed matter displayed on the color monitor 86. The color display circuit displays various combined images of each color of Y, M, C, and K. The gamma correction circuit can independently adjust each color of Y, M, C, and K, and corrects the gamma characteristics of plate making and printing. Also, four types of presets are possible. The color patch circuit is a function that stores a color (level of four colors) of a certain point (2 cm × 2 cm area) and displays the color as necessary for the second and subsequent documents. .
Thus, the same portion of a series of color originals can be reliably printed in the same color. When a color photograph is used for a document, the color of the document itself may be shifted, but this function can correct this. The output of the D / A conversion unit 80 is supplied to the matrix circuit 82. The matrix circuit 82 has a printing system signal Y,
A circuit for converting the M, C, and K image signals into R, G, and B image signals, which are television signals, and converts the amount of ink into R, G, and
This is a circuit for converting the luminance of the B color beam. The output of the matrix circuit 82 is supplied to the monitor circuit 84. The monitor circuit 84 performs curve correction (correction of non-linearity generated in the color monitor), peaking correction, white frame level adjustment, and dark level adjustment. The R, G, B image signals output from the monitor circuit 84 are input to a color monitor 86, and a print image is displayed (simulated). Here, a non-interlaced monitor of about 20 inches is used as the color monitor 86.
It is preferable that the color monitor 86 has good white uniformity. The print simulation apparatus 2 further includes an operation panel 90 for giving various operation commands and a timing generator 92 for giving various operation timings. The operation items of the operation panel 90 are as follows: scan mode, film size (35 mm, 6 × 7 inch, 4 × 5 inch, 8 × 10 inch), channel select (4 ch), rotation / inversion, color display (Y, M, C, K),% display (joystick, on / off), enlargement (× 2, × 4, position), white background (size, position, color), comparison of two images (switch, scroll volume), Flashing (level setting, flashing for each color, K is off switch), image transfer (line memory → hard disk device), image transfer (hard disk device →
Frame memory 62), comparison of two images (frame memory 76 → frame memory 78, hard disk device → frame memory 7)
8), image transfer (hard disk device → frame memory 7)
8) Comparison of 2 images → hard disk device, image transfer (frame memory 76 → frame memory 78 → hard disk device), 16 images comparison. Here, the scan mode is an operation mode of the color scanner 4 (read head 14), and has four modes of quick / normal / stop / restart. When the quick scan switch is off, the reading mode is the normal mode. The fine scan mode is specified not when simulating but when exposing an actual color separation plate. In this case, the image signal is thinned out and displayed on the color monitor 86. When the stop switch is closed during quick scan, the color scanner 4
The color scanner 4 does not stop even if the stop switch is closed during fine scanning. The input / output signals of the timing generator 92 are as follows. Input signals: color separation start signal, encoder pulse, start, cropping, drum size, magnification, screen ruling, dark, original size, rotation, inversion, enlargement. Output signal: mode signal, traverse signal, synchronization signal (sy
nc), a line memory control signal, a frame memory (62) control signal, a frame memory (76) control signal, a frame memory (78) control signal, and a hard disk drive control signal. Next, the printing simulation apparatus 2 according to this embodiment
The operation method will be described. The operator sets the color separation conditions considered to be preferable when viewing the color document 12 in the masking circuit 24, the under color removal circuit 26, and the gradation correction circuit 28. Then, the color original 12 is attached to the reading drum 10, and coarse reading for simulating a print image is performed. For example, 4 × 5
For inch film, set the color scanner magnification to 32.
% (0.32 times), the entire screen of the color document 12 is scanned by 512 scanning lines,
The image signal of the color document 12 is read. This image signal is input from the calibration circuit 18 to the print simulation device 2 and stored in the frame memory 62. At the same time, the image signal is color-corrected by the color correction circuit 22 and then input from the channel selector 32 to the print simulation device 2 and stored in the frame memory 76. Frame memory
A print image is simulated based on the output of 76 and displayed on the color monitor 86. If the image on the color monitor 86 has a preferable color tone, the color separation film 42 is attached to the exposure drum 40, the color original 12 is fully scanned, and color separation work (film exposure) is performed. If the color tone of the image on the color monitor 86 is not favorable, the correction amount of the color correction circuit 22 is adjusted to change the color separation condition, and the signal stored in the frame memory 62 is again transmitted to the color correction circuit 22. The color is corrected and input to the print simulation device 2 from the channel selector 32 to change the color tone of the display image on the color monitor 86. In this way,
After confirming the color tone of the print image under each color separation condition on the color monitor 86 without forming a color separation plate, the color separation operation is performed, whereby the plate inspection can be substantially performed. [Effects of the Invention] As described above, according to the printing simulation apparatus of the present invention, the image signal before color correction is read by the color scanner and temporarily written into the first frame memory.
The signal read from the first frame memory is color-corrected by the color correction circuit of the color scanner, the color-corrected signal is written to the second frame memory, and based on the signal read from the second frame memory. Adjust the color correction amount while simulating the print image on the color monitor screen,
At the same time that the color separation conditions are determined, the color separation conditions can be set in the color correction circuit. For this reason, the color separation conditions of the color scanner are simply and accurately compared to manually adjusting the color separation conditions adjusted and determined in the print simulation apparatus to the color correction circuit of the color scanner. Can be set. The present invention is not limited to the above-described embodiment, and can be variously changed without changing the gist.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of a printing simulation apparatus according to the present invention. 2 Print simulation device, 4 Color scanner, 10 Reading drum, 14 Reading head, 22
Color correction circuit, 32 channel selector, 36 dot generator, 38 exposure head, 40 exposure drum,
62: Frame memory, 68: Hard disk drive, 7
6,78 …… Frame memory, 86 …… Color monitor, 90 ……
control panel

Continuation of front page    (72) Inventor Takashi Kuramoto               1-5-1, Taito, Taito-ku, Tokyo Letterpress               Printing Co., Ltd. (72) Inventor Takeo Onga               1-5-1, Taito, Taito-ku, Tokyo Letterpress               Printing Co., Ltd. (72) Inventor Kosei Suzuki               1-5-1, Taito, Taito-ku, Tokyo Letterpress               Printing Co., Ltd. (72) Inventor Ken Suwa               404-2 Setooka, Akikawa City, Tokyo                (56) References JP-B-59-822 (JP, B2)

Claims (1)

(57) [Claims] In a printing simulation apparatus connected to a color scanner for creating a color separation based on a signal obtained by color-correcting an image signal representing an image of an original obtained by reading a color original, , G, and B color image components, and a second storage unit that stores a second image signal composed of color components of the printing ink after color correction in the color scanner. Means, image processing means for performing image processing on a second image signal stored in the second storage means for each color component of printing ink to obtain an image signal for each color component of printing ink; Means for converting a second image signal for each color component of the printing ink output from the means into an image signal composed of R, G, B color components, and displaying a simulation image of a printed matter, Printing simulation apparatus first image signal stored in the serial first storage means, characterized in that it is supplied to the color correction means of the color scanner. 2. The first image signal before the color correction is applied only once to the first image signal.
And the second image signal after the color correction is written into the second storage means at a speed synchronized with the operation speed of the color correction means of the color scanner. 2. The printing simulation apparatus according to claim 1, wherein the second image signal is read from the means at a speed synchronized with the operation speed of the display means.