JPH0654945B2 - Print simulation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention adjusts color separation conditions (various color correction amounts) when a color original is printed in color, and substantially performs plate inspection (check of separation conditions). The present invention relates to a print simulation apparatus for simulating a print image on the screen of a color monitor in order to perform the operation, and particularly to a print simulation apparatus used in combination with a general color scanner and convenient for proofreading.

[Prior art]

When performing color printing, read the color original with a color scanner, perform various color corrections on the read image signal, and then
Color separation is performed and a color separation version is created according to the color separation signal. Then, a printing plate for proof printing is made from the obtained color separation plate, and the printing plate for proof printing is put on a proof printing machine to perform proof printing. Judge whether the color separation condition (color correction amount) of the scanner is appropriate from the color tone of the proof, and if the color tone of the proof is not the desired color tone, change the color separation conditions and correct the color again, and then perform the color separation again. Create and proof print. When a proof print having a desired color tone is obtained, a practical plate is prepared under the disassembling conditions, and the actual printing is carried out on a printing machine (practical machine).

By the way, since such proof printing requires a considerable amount of time, cost, and labor, various printing simulation apparatuses using a color monitor have been developed in recent years, and even if proof printing is not performed, the finished state of printed matter can be improved. Is simulated on a color monitor and it is possible to inspect.

[Problems to be solved by the invention]

As described above, in the conventional print simulation apparatus, the simulated image for each color original document is simply displayed on the monitor screen, and it is not possible to compare it with the portion having the same color tone in other color original documents. Therefore, when a plurality of color originals are used as one printed matter, the colors that should be the same cannot be exactly the same. In general, the color tones of the color originals themselves are not exactly the same, but they are slightly different.
The color separation conditions of the tones that appear to be the same on the manuscript do not become unconditionally the same.

This invention has been made to deal with the above-mentioned circumstances,
It is an object of the present invention to provide a print simulation apparatus capable of comparing the color tones of corresponding portions of a plurality of color originals when a simulated print image obtained by color-correcting an image signal obtained by reading a color original is displayed on a monitor. .

[Means for solving problems]

A printing simulation apparatus according to the present invention includes a data latch circuit 104 that stores an image signal of a predetermined pixel of a color-corrected image signal, and a predetermined pixel when displaying a color-corrected image signal of another color original. A signal switcher 10 which supplies this stored signal to the monitor instead of the simulated signal of
2 and.

[Action]

According to the print simulation apparatus of the present invention, when the simulated print image is displayed on the monitor, the color tone of the reference original is displayed for the predetermined area instead of the simulated image, so that the plurality of color originals among the plurality of color originals are displayed. The color tones of the areas that should be the same can be made exactly the same.

〔Example〕

An embodiment of a print 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 print simulation device 2 is connected to the color scanner 4. The print simulation device 2 is arranged below the color scanner 4 and on the back. However, the color monitor 86 and the operation panel 90 are different, 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, manufactured by Dainippon Screen Mfg. Co., Ltd.)
Etc. can be used.

In the color scanner, the color original 12 mounted on the reading drum 10 is rotated by the reading drum 10 and the reading head.
Scanning is performed by moving 14 and image information is read. The reading head 14 is provided with a photomultiplier as a photoelectric conversion element, and the obtained image signal is converted into R, R (green), blue (B) filters by a beam splitter.
Output as G and B image signals.

The R, G, and B image signals output from the reading head 14 are current / voltage converted by a current / voltage (C / V) converter 16,
It is supplied to the calibration circuit 18 and the level is adjusted. The output signal of the calibration circuit 18 is logarithmic (LO
G) After being logarithmically compressed by the amplifier 20, it is supplied to the color correction circuit 22.

Color correction circuit 22 is masking circuit 24, under color removal (UCR)
It comprises a circuit 26, a gradation correction circuit 28, a negative / positive conversion circuit (not shown), a dot% display circuit (not shown), etc., and performs 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,
The R, G and B signals are converted into yellow (Y), magenta (M) and cyan (C) signals. The under color removal circuit 26 is the basic printing 4
To print in Y, M, C, K (black), which is the color, Y,
The M and C signals are converted into Y, M, C and K signals. The gradation correction circuit 28 performs gradation correction such as highlight set, shadow set, middle separation, highlight separation, and shadow separation. The amount of these corrections,
By appropriately adjusting the correction amount, the color separation plate produced has a preferable color tone.

This color correction circuit 22 performs color correction, and Y,
The M, C, and K image signals are logarithmically expanded by an antilogarithmic (LOG ^-1 ) amplifier 30, and then supplied to a channel (CH) selector 32.

The channel selector 32 selects which color signal is output depending on whether the four color separation films are exposed simultaneously or one color at a time. Channel selector
After the output of 32 is converted into a digital signal by the analog / digital (A / D) converter 34, the dot generator 36
Is supplied to.

The dot generator 36 converts the image signal into a halftone dot signal for recording as a halftone 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 according to the halftone dot signal whose magnification is controlled. A color separation plate is created by developing the color separation film 42.

The color scanner 4 is connected to the print simulation device 2 at the output end of the calibration circuit 18 and the output end of the channel selector 32. That is, the output signal of the calibration circuit 18 (the 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. To be done. Alternatively, the output signals of the logarithmic amplifier 20 and the gradation correction circuit 28 are supplied to the print simulation device 2, and the signal from the print simulation device 2 is supplied to the masking circuit.
May be entered in 24.

The R, G, B signals from the calibration circuit 18 input to the print simulation device 2 are level adjusters 50,
It is written in the line memory 60 which is a semiconductor memory through an interface (I / F) circuit 56 including an averaging circuit 54 and the like and an 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, and in the print simulation apparatus 2 it is 0.7 Vpp which is a general video signal, so level conversion is necessary. The averaging circuit 54 is a kind of low-pass filter circuit, which averages the input image signal to restore it to a smooth signal to some extent and controls it in accordance with the sampling frequency in A / D conversion. The details of the interface circuit 56 are described in Japanese Patent Application No. 61-55514, so detailed description will be omitted.

The line memory 60 is a buffer memory,
The output of 60 is a frame memory which is also a semiconductor memory
Written in 62. Frame memory 62 is 512 x 512 (pieces) x
Each pixel of 3 (color) is stored in 8 bits (256 density steps). The frame memory 62 changes the horizontal address and vertical address at the time of reading so that the image is rotated 90 ° left and right.
Can rotate.

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 reading head
The signal from 14 is supplied to the color correction circuit 22.

One image is read by the color scanner 4 and the drum 10
It takes about 20 seconds to read at 512 rotations, and the frequency band of the color correction circuit 22 is designed to be about 200 KHz. Therefore, the input to the frame memory 62 is about 20 seconds and the output is the color correction circuit.
In order to match the 22 frequency bands, one image signal is read from the frame memory 62 in about 2 seconds.

The output of the line memory 60 is also supplied to the hard disk device 68 via the thinning circuit 66. The hard disk device 68 is a cassette type, has a storage capacity of about 20 MB, stores image signals for 18 screens, and reduces one screen to 1/16.
Further, the output of the line memory 60 is directly supplied to the hard disk device 68. Line memory
The thinning circuit 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, K signals from the channel selector 32 input to the print simulation device 2 are also written in the frame memory 76, which is a semiconductor memory, through the interface circuit unit 72 and the A / D converter unit 74. .

Like the interface circuit unit 56, the interface circuit unit 72 has a level adjuster and an averaging circuit, and also has a negative / positive conversion circuit, a thinning circuit, and a cropping circuit.

Negative / positive conversion is performed only when the color original 12 is a negative original, and an error in conversion is within ± 1%. Further, the negative / positive conversion can be selectively performed only on any 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 original 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 gradation). The frame memory 76 has a pixel enlargement function (x2, x4), a reversal function (vertical and horizontal), a two-image comparison display function, and a non-interlaced output function. With the enlargement function, it is possible to display the enlarged area and move the area. Also, the display area after enlargement can be moved. The reversing function is a function of reversing the image vertically and horizontally. The two-image comparison display function is a function of displaying two images side by side in one screen by using the frame memory 78, comparing an image before color correction and an image after color correction, and comparing two images. Used to unify the color of certain parts of the image (eg background). At this time, left and right scrolling is possible.

The output of the frame memory 76 is supplied to the D / A conversion unit 80. The D / A conversion unit 80 has a flushing circuit, a dot% display circuit, a white frame display circuit, a color separation display circuit, a gamma correction circuit, a white clip circuit, and a color trace circuit.

The flushing circuit flushes pixels of 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, each color is flushed, and in three colors, it is gray (Y, M, C halftone dots 40%).
Flush with. Further, even four colors can be flushed, and in this case, the K plate is also flushed with about 40% of halftone dots.

The dot% display circuit displays a movable "+" mark on the screen of the color monitor 86, and the Y, M, and
Outputs DC levels of C and K.

The white frame circuit displays a pure white (paper white) frame on the outside of the printed matter displayed on the color monitor 86.

The color separation display circuit displays various combination pixels of Y, M, C and K colors.

The gamma correction circuit can adjust the Y, M, C, and K colors independently, and corrects the gamma characteristics of plate making and printing. Also, four types of presets are possible.

The color trace circuit has a function of storing a color of a certain pixel (levels of signals of four colors) and displaying the color on the second and subsequent originals as needed. This allows
It is possible to reliably print the same portion of a series of color documents as the same color. When using a color photo on a document, the color of the document itself may be misaligned, which can be corrected by using this function. Here, it is used for color matching between a plurality of originals such as unifying product color back colors or unifying product colors (automobiles, home appliances, furniture, etc.). For example, if there are 10 color originals and the colors of the back are to be unified, the first original is finished in an appropriate tone, and at this time, one pixel of the 2cm x 2cm square color patch of the back is used. When the signal is latched and the next original is simulated, the latch data is read and displayed on the same background. At this time, the back color can be unified by moving the color correction knob of the color scanner 4 to match the back color tone with the color tone of this color patch.

An example of the color trace circuit is shown in FIG. The image signal read from the frame memory 76 is supplied to the color trace circuit 100 for each color. In FIG. 2, only one color trace circuit 100 is shown for the sake of simplicity. The image signal is supplied to the first input terminal of the signal switch 102 and also to the data latch circuit 104. The output of the data latch circuit 104 is supplied to the second input terminal of the signal switch 102. The latch signal generated from the timing signal generator 106 according to the synchronization signal is supplied to the data latch circuit 104. The display switching signal generated from the display control signal generator 108 according to the signal from the timing signal generator 106 is supplied to the signal switching device 102. In response to this display switching signal, the signal switching device 102 switches between the output of the frame memory 76 and the output of the data latch circuit 104. The output of the signal switch 102 (the output of the color trace circuit 100 for each color) is supplied to the matrix circuit 82 via the D / A converter 110.

When performing color tracing, first, when simulating the first color original of a series of color originals, the signal switching unit 102 is connected to the output side of the frame memory 76, and the simulated print image is displayed. Display on color monitor 86.
Then, the pointer cursor points to one pixel on the screen. The timing signal generator 106 generates a latch signal in synchronization with the timing when the image signal of the designated pixel is read from the frame memory 76. As a result, the pixel signal is stored in the data latch circuit 104 as the reference color tone. The latched 1-pixel signal is held until the next new data is latched.

When simulating the second and subsequent originals, the display control signal generator 108 switches the display when the simulation image near one pixel (color patch) latched based on the timing signal is read from the frame memory 76. A signal is generated and the signal switch 102 is switched to display the stored signal of the data latch circuit 104 on the color monitor 86 instead of the simulation image. This facilitates comparison with the color tone of a predetermined pixel of the previous document.

In order to make it easy to see the latched 1-pixel signal, the display switching signal is not limited to that pixel, but to what area (color patch) around that pixel the pixel is expanded and displayed, that is, the size of the color patch. This is a signal for determining the height. That is, the output of the data latch circuit 104 is supplied to the color monitor 86 only while the signal switch 102 is switched to the data latch circuit 104 side. The display control signal generator 108 is composed of an AND circuit and includes a frame memory 7
When the timing signal for determining the read address of the signal from 6 represents the address in the color patch, a display switching signal (switching the signal switching device 102 to the data latch circuit 104 side) is generated. The size of the color patch can be freely changed, but here it is set to 2 cm x 2 cm.

Although not shown, it is also possible to display the dot% for each color of the latched pixel signal and the dot% for each color of the simulation image, and adjust the color tone by the number of dot%.

Returning to FIG. 1, the output of the D / A conversion unit 80 is supplied to the matrix circuit 82. The matrix circuit 82 is a circuit for converting Y, M, C, and K image signals which are printing signals into R, G, and B image signals which are television signals, and the ink amount is R and G. , B of the color beams.

The output of the matrix circuit 82 is supplied to the monitor circuit 84.
The monitor circuit 84 performs curve correction (non-linear correction generated in a color monitor), peaking correction, white frame level correction, and dark level correction.

The R, G, and B image signals output from the monitor circuit 84 are input to the color monitor 86, and a print image is displayed (simulated). Here, as the color monitor 86, a non-interlaced monitor of about 20 inches is used.
Further, 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 cm, 4 × 5 inch, 8 × 10 inch) channel select (4c
h), rotation / reversal, color display (Y, M, C, K),% display (joystick, on / off), enlargement (x2, x)
4, position), white background (size, position, color), 2 image comparison (switch, scroll volume), flushing (level setting, flushing in each color, YMC and YMCK)
Image recording (line memory 60 → hard disk device 68), image recording (frame memory 76 → hard disk device 68), image playback (for RGB images,
Hard disk device 68 → frame memory 62 → color correction circuit
22 → frame memory 76, in the case of YMCK images, hard disk device 68 → frame memory 78), multi-image display (16 images displayed in hard disk device 68), image transfer (frame memory 76 → frame memory 78), image transfer ( Frame memory 78 → frame memory 76).

Here, the scan mode refers to the operation mode of the color scanner 4 (reading head 14), which is quick / normal /
There are three modes of stop. When the quick scan switch is off, the reading mode is normal mode. The normal scan mode is specified when the actual color separation plate is exposed, not at the time of simulation, and at this time, the image signal is thinned out and displayed on the color monitor 86. When the stop switch is closed during the quick scan, the color scanner 4 also stops, but even when the stop switch is closed during the fine scan, the color scanner 4 does not stop.

The input / output signals of the timing generator 92 are as follows. Input signal: Color separation start signal, encoder pulse,
Start, cropping, drum size, magnification, screen ruling, dark, original size, rotation, flip, enlarge. Output signal: Mode signal, traverse signal, sync signal (sync),
Line memory control signal, frame memory (62) control signal, frame memory (76) control signal, frame memory (78) control signal, hard disk control signal.

Next, a simulation method by the print simulation apparatus 2 according to this embodiment will be described. The operator sets the color separation conditions, which are considered preferable when viewing the color original 12, in the masking circuit 24, the undercolor removal circuit 26, and the gradation correction circuit 28. Then, the color original 12 is attached to the reading drum 10, and rough reading is performed for simulation of the printed image. For example, in the case of a 4 × 5 inch film, the entire size of the screen of the color original 12 is 512 by automatically controlling the magnification of the color scanner 4 to 32% (0.32 times).
The image signal of the color original 12 is read by scanning with the scanning line of the book. This image signal is input to the print simulation device 2 from the calibration circuit 18 and stored in the frame memory 62. At the same time, the image signal is sent to the color correction circuit 22
After being color-corrected by, the data is input from the channel selector 32 to the print simulation device 2 and stored in the frame memory 76. A print image is simulated based on the output of the frame memory 76 and displayed on the color monitor 86.

If the image on the color monitor 86 has a desirable tone,
A color separation film 42 is attached to the exposure drum 40, the color original 12 is subjected to main scanning, and color separation work (film exposure) is performed. If the color tone of the color monitor 86 is not preferable, the correction amount of the color correction circuit 22 is adjusted to change the color separation condition, and the stored signal of the frame memory 62 is corrected by the color correction circuit 22 again. , Input from the channel selector 32 to the print simulation device 2 to change the color tone of the image displayed on the color monitor 86. In this way, the color tone of the printed image under each color separation condition is checked on the color monitor 86 without making a color separation plate, and then the color separation work is performed, whereby the plate inspection can be substantially performed.

〔The invention's effect〕

As described above, according to the printing simulation apparatus of the present invention, the color separation conditions of the color scanner can be set easily and accurately. Further, according to the present invention,
Since the pixel signal of an arbitrary portion within one screen can be stored, the storage signal is read out and displayed in the corresponding portion in the simulation of another color original, so that the corresponding portion of a plurality of color originals is displayed. Can have the same color tone.

The present invention is not limited to the above-described embodiments, and can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a printing simulation apparatus according to the present invention, and FIG. 2 is a block diagram of a color trace circuit in this embodiment. 2 ... Print simulation device, 4 ... Color scanner, 10 ... Read drum, 14 ... Read head, 22 ...
Color correction circuit, 32 ... Channel selector, 36 ... Dot generator, 38 ... Exposure drum, 40 ... Exposure drum,
62 …… Frame memory, 68 …… Hard disk device, 7
6, 78 …… Frame memory, 86 …… Color monitor, 90…
… Operation panel, 100 …… Color trace circuit, 102 …… Signal switch, 104 …… Data latch circuit, 106 …… Timing signal generator, 108 …… Display control signal generator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Ongawa 1-5-1 Taito, Taito-ku, Tokyo Within Toppan Printing Co., Ltd. (72) Inventor Akio Suzuki 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Ken Suwa 402-2 Setooka, Akigawa City, Tokyo (56) References JP-A-58-43456 (JP, A) JP-B-59-822 (JP, B2)

Claims (1)

[Claims] 1. A print simulation apparatus connected to a color scanner for creating a color separation plate based on a color-corrected image signal obtained by reading a color original, and a printed matter based on the color-corrected image signal. Means for displaying the simulation image, a means for storing the image signal of a predetermined pixel of the simulation image of the printed matter obtained from a certain color original which is a reference color for color correction, and a means obtained from another color original. A printing simulation apparatus comprising: a unit for displaying an image signal read from the storage unit instead of the image signal of a predetermined pixel when displaying a simulation image of a printed matter.