JPS62259180A - Printing simulator - Google Patents

Abstract

PURPOSE:To attain plate checking work without making a separation plate and to reduce time and costs and to improve operability by adjusting a color calculation circuit composed of a masking circuit, an under-color removal circuit and a gradation correction circuit. CONSTITUTION:The gradation correction circuit 146 is set to zero beforehand, and the color separation condition that a color original 2 is favorable for is set to the masking circuit 40, the under-color removal circuit 42 and the gradation correction circuit 44. The original 2 is placed on a drum 30, and roughly read in order to simulate it to a color monitor 152. Simultaneously a printed picture is simulated under the color separation condition set to the circuits 40, 42 and 44. If the picture of the color monitor 152 is favorable, a film 6 is set to a recording drum 70, and color is separated. If the picture of the monitor 152 is unfavorable, the circuit 146 is adjusted to separate color. Thus an efficient plate checking work can be attained without the separation plate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a printing simulation device using a color monitor for setting color separation conditions for printing a color original in color and for substantially checking the plate. In particular, the present invention relates to a printing simulation device that is convenient for proofreading in combination with a general color scanner. That is,
An image signal and a reading timing signal are extracted from a commonly used conventional color scanner or i = Kuwata Domi, and these are input into a simulation unit that has an IC memory, a color calculation circuit, a color monitor, etc., and the printed image is printed. Preferred color separation conditions are set by simulating a likely image on a color monitor and adjusting the color calculation circuit, and correction conditions are set by performing color separation through the color calculation circuit of this simulation unit during color separation. This invention relates to a printing simulation device that can perform color separation.

[Prior art]

When printing in color, a color document is separated into colors using a color scanner, a proof printing plate is made using the color separation plates obtained, and the proof printing plate is applied to a proof printing machine to perform proof printing. If a proof with a desired color tone cannot be obtained, the colors are separated and the proof is made again.

Once 1q of preferred proofs have been produced, a working plate is made from the color separation plate and printed using a printing press.

By the way, since such proof printing requires a considerable amount of time, money, and labor, various printing simulation devices using color monitors have been developed in recent years, and it is possible to check the condition of the finished printed matter without making proof printing. Simulation is performed on a color monitor, and it is now possible to set approximately preferred color separation conditions and inspect the plate.

As such a conventional printing simulation device,
For example, as seen in a plate inspection device as described in U.S. Pat. No. 3.972.066, and a calibration condition setting device as described in U.S. Pat. No. 4.240.522, a type of printing simulation that is completely independent of a color scanner is available. There is a device.

On the other hand, there are printing simulation devices incorporating a color scanner printing simulation device such as JP-A-5O-15fG No. 10 (Dainippon Screen Mfg. Co., Ltd.) and JP-A-52=125001Q (Dr.
There is also a type of printing simulation device, such as that manufactured by Ingeniere Rudolf Hell, which combines a color scanner and a printing simulation device by sharing part of the device.

[Problems with conventional technology]

Each format has its own advantages and disadvantages, but conventional printing simulation devices cannot be easily attached to various existing color scanners, and do not utilize many parts of color scanners, making it difficult to perform simulations. There were many parts, and the approximation of the image was poor. In other words, there is no printing simulation device that satisfies all of the following conditions: it can obtain high-quality simulation images with fewer simulation parts, it can quickly simulate not only colors but also images, and it has good workability. Ta. Furthermore, especially in the case of an independent printing simulation apparatus, there is a drawback that the obtained correction conditions must be set again in the scanner.

[Problems solved by the invention]

An object of the present invention is to provide a printing simulation device that satisfies all of the above problems. That is, the printing simulation device of the present invention can be easily applied to various existing color scanners, and by using many parts of the color scanner, it is possible to use separated plates as input documents without creating separated plates. It is possible to perform the same so-called inspection version as when simulating the image, and it can be simulated in a short time without requiring a lot of time to simulate the image.
Moreover, it is a printing simulation device with good workability, since it is not necessary to set the obtained correction conditions again in the scanner.

[Means for solving problems]

The printing simulation device of the present invention is configured to output both signals to the simulation unit side after passing through color calculation circuits such as a masking circuit, an undercolor removal circuit, and a gradation correction circuit in a color scanner. The apparatus includes an interface section, an IC memory, a color calculation circuit, a curve correction circuit, a YMCK/RGB conversion circuit, a color monitor, an address control circuit, and a simulation section such as a bypass for plate making through the color calculation circuit of the simulation unit.

[For production]

First, after setting the color calculation circuit of the color scanner to obtain the desired color tone, a color document is roughly scanned (512 lines) to the extent required for the television, one frame of this image is stored in the IC memory, and the IC This stored image is read out from the memory and a printing original is simulated on a color monitor through a color calculation circuit (gradation correction circuit) of a simulation unit set in advance. If this image is not desirable, the gradation correction circuit is adjusted to make corrections so that the image of the simulation unit becomes desirable.

Then, during color separation, the data is passed through a gradation correction circuit by bypass (after making rough corrections such as Sun, F), and the actual color separation is performed using a color scanner.

〔Example〕

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 apparatus according to this embodiment includes a color scanner 20 and a simulation unit 110. The color scanner 20 can employ various conventional devices, and the color scanner of this embodiment is also a well-known so-called direct scanner (SG).
818, Dainippon Screen Mfg. Co., Ltd.), detailed explanation will be omitted. In addition, the simulation unit 110 includes an A/D converter 140, an IC memory 142, a D/A converter 144, and a gradation activation circuit 146.
, the color correction circuit 148, the matrix circuit 150, the color monitor 152, etc. have almost the same functions as the corresponding parts described in the specification of U.S. Pat. Explanation will also be omitted.

The color original 2 attached to the reading drum 30 is scanned by the rotation of the reading drum 30 and the movement of the reading head 32, and the beam splitter, blue (B), green (G), and red (R) filters in the reading head 32 are scanned. B, G, and R image signals are obtained by a photoelectric cell and the like.

The obtained B, G, and R image signals are current 7/voltage (C/V
) A converter 34 performs current/voltage conversion, a logarithmic converter 36 performs logarithmic conversion, and a calibration circuit 38 adjusts the level.

The next masking circuit 40, undercolor removal circuit 42, and gradation correction circuit 44 are so-called color correction circuits that perform color correction and correction for printing, and the masking circuit 40 performs so-called masking correction and removes undercolor. The circuit 42 corresponds to the four basic colors of the marking section 11: yellow (Y), magenta (M), and cyan (C).
, l (K) to print the YlM,C signal to Y,M
The gradation correction circuit 44 performs gradation correction such as compression, highlight, shadow, contrast, and pedestal.

By appropriately adjusting these correction and correction circuits, the printed image will have a desirable color tone.

After correcting and correcting the color with this color calculation circuit, Y,
After the image signals of M, C, and A are inversely converted by the inverse logarithmic converter 50 and the format to be recorded on the film 6 on the recording drum 7G is set by the channel selector 52,
The signal is converted into an analog/digital signal by a /D converter 60 and used as a signal to be recorded as halftone dots by a dot generator 62, and the magnification of the film 6 relative to the color original 2 is also set. The recording head 66 exposes the film 6 on the recording drum 7G according to the magnification-controlled image signal.

By developing this film 6, a fine separation plate is obtained.

Y after passing through the color calculation circuit of this color scanner 2G,
The image signals 5 of M, C, and C (in this embodiment, the output image signals of the channel selector 52) are supplied to the simulation unit 110. The control device 12 is for controlling the entire color scanner 20, and this control device 1
In particular, a timing signal for reading the color original 2 is sent to the simulation units 1 to 110 (A/D converter 1401 address control circuit 126) by 2.

The simulation unit 110 has a level adjuster 120
, an interface section such as the averaging circuit 124, and an A/D converter 140. IC memory 142, D/A converter 144
, gradation correction circuit 146, curve correction circuit 147, color correction circuit 148, matrix circuit 150, color monitor 1
Simulation unit such as 52, and address control circuit 1
It consists of 26 mag.

The level adjuster 120 adjusts the handling voltage level of the image signal from the color scanner 20 to the simulation unit 110.
This is a level conversion. In this embodiment, the color scanner 20 handles the TTL level (0 to 5V), and the simulation unit 110 handles the video signal as a general 0.7Vpp, so it is necessary to perform this level conversion.

In this embodiment, the averaging circuit 124 is a kind of low-pass filter circuit, and is a circuit for averaging the input image signal, converting it into a somewhat smooth signal, and eliminating deviations in sampling. That is, the image of the color original 2 generally has much more detailed density data than the image of the color monitor 152. That is, the image signal obtained by scanning the color original 2 has density data that changes minutely as shown by the solid line in FIG. 2 because the scanner has high reading accuracy and scans with high resolution.

By the way, when storing this image signal in the IC memory 142 in order to display it on the color monitor 152, the IC memory 14
2, the image signal of one screen is 512 x 51 due to capacity.
It is stored extremely roughly as m degrees of two pixels. That is, each scanning line is sampled and stored so as to be equally divided into 512 sections.

However, since the image signal has detailed density data as shown in Figure 2, depending on the sampling point, it is possible to limp and capture a degree that is shifted by △Y from the average density (dotted chain line in the figure). There is. Of course, the smaller the difference in sampling, the better, so it is preferable to sample the image signal after averaging it to some extent (that is, after converting it into a smooth signal as shown by the dashed line in the figure). In order to convert this image signal into a gently averaged signal in the averaging circuit 124, it is preferable to pass it through a low-pass filter. In this case, the cutoff frequency should be selected appropriately depending on the size of the reading drum 30 and the diameter of the reading drum 30.

Here, examples of the diameter, sampling frequency, and cutoff frequency of the reading drum 30 of this embodiment are shown.

However, the number of samplings is 512 times in the rotational direction (main scanning direction), and the rotational speed of the reading drum 30 is constant at 1200 rotations/rotation regardless of the diameter. The size (circumference) of the reading drum 30 is 565 am for a large drum.
(peripheral speed is 11,300 mu/s), middle drum is 283
tryt (circumferential speed is 5560 N11/sec), small drum force 142m (circumferential speed is 2840IIIrI/sec)
It is. Film size (effective sampling length) is 35
m film is 24711111X35 M and 6X
7 cell film is 55JIIIX68M, 4x51nch film is 96sX122#l1m, 8X101nch film is 192#X244
rM&.

In this way, by using a low-pass filter circuit as the averaging circuit 124 and appropriately adjusting its cutoff frequency, deviations in sampling can be eliminated and images can be photographed and stored preferably.

As the averaging circuit 124, a circuit other than the low-pass filter' may be employed.

When storing the image signal averaged by the averaging circuit 124 in the IC memory 142, the A/D converter 140 samples it at the frequency shown in the table above so that each scanning line has 512 pixels. It is converted, sent to the IC memory 142, and stored.

The 1G memory 142 stores 512x512x4 (color) in 8 bits (256a degree steps).
When storing and reading data in the C memory 142, the address control circuit 126 stores the data in synchronization with the reading of the color original 2, and controls the vertical and horizontal relationships as follows. That is, the addresses are arranged in a matrix as shown in FIG. When a color document 2 with a person lying down is placed on the reading drum 30 as shown in FIG. 1, the first scanning lines are (1,1), (1,2), (1, 3>
, ..., (1,512>, second scan line (2,1
), (2,2>, (2,3), ..., (2,512>
Store it in the memory address as follows.

During reading, due to a mirror phenomenon, the first scanning line displayed on the color monitor 152 is (1,512>
, (1,511>, (1,510) , ..., (1°1), as the second scanning line (2,512>, (2,51
1>, (2,510), . . . , (2,1), and so on. As a result, the person is displayed on the color monitor 152 while standing.

Furthermore, if the color original 2 is placed on the reading drum 30 while a person is standing, the first scanning line is (1,512
>, (2,512), (3,512>, ... (51
2°512), the second scanning line (1,511), (2,
511>, (3,511) ,..., (512,51
If it is stored in a memory address as in 1) and read out in the same manner as described above, a person will be displayed in a standing position.

In this way, by controlling the addresses for the vertical and horizontal relationships during storage and for the mirror phenomenon during reading, an image can be displayed correctly on the color monitor 152. The image is stored in the IC memory 142 using the reading drum 30.
When the rotation speed is 120 Or, p, m, one screen is memorized in about 26 seconds. Furthermore, reading from the IC memory 142 is performed at a rate of 30 frames/second for displaying on the color monitor 152. Storing and reading from the IC memory 142 can be performed simultaneously, and the IC memory 142 is configured so that it can be read (displayed on the color monitor 152) while being stored.

The image signal read out from the IC memory 142 is subjected to D/A conversion by a D/A converter 144, and then input to a gradation correction circuit 146, which is a color-specific calculation circuit. In this example, only this gradation correction circuit 146 is arranged as a color meter circuit, and it is possible to adjust compression, highlights, shadows, contrast, pedestal, etc. The tone-corrected image signal is input to the curve correction circuit 147.

The curve correction circuit 147 performs curve correction to match the conditions of the printing process. For example, (1) the thickening and thinning of the halftone dots changes in a curved manner due to the reversal of negative/positive film, so this is corrected. (2) The ink spreads due to the application of printing pressure during proof printing, and this is corrected in a curved manner.

(3) In areas where halftone dots are large, adjacent dots overlap, and since the density of such areas does not increase in accordance with the signal strength, this area is corrected in a curve-like manner.

The next color correction circuit 148 and matrix circuit 150 are circuits for converting Y, M, C, and printing system signals into B, G, and R image signals that are television system signals. . The color correction circuit 148 is a circuit that mainly corrects nonlinearity caused by overlapping ink, and the matrix circuit 150 is a circuit that converts the color amount of ink into the color amount of fluorescent color of the television. The details of such a circuit are described in the above-mentioned US Pat. No. 3,972,066, Japanese Patent Application Laid-Open No. 58-52642, etc., so detailed explanation will be omitted.

The image signals converted into television image signals B, G, and R by this circuit are input to the color monitor 152 and displayed.

The switches 180, 182, 184, 186 and the level adjuster 192 are bypasses for allowing color separation to be performed through the gradation correction circuit 146 when color separation is performed by a color scanner. In other words, when setting the decomposition conditions, switch 180-1
86 is connected to the upper terminal as shown in the figure. However, during color separation, by connecting to the lower terminal, color separation can be performed through the gradation correction circuit 146. The level adjuster 192 converts from 0.7Vpp to TTL level.

Next, a method of operating the printing simulation apparatus according to the first embodiment will be explained. The operator looks at the color original 2 and sets desired color separation conditions to the masking circuit 40, the undercolor removal circuit 42, and the gradation correction circuit 44. The tone correction circuit 146 is set to O in advance. Then, the color original 2 is placed on the reading drum 30, and rough reading is performed for displaying it on the color monitor 152. For example, in the case of a 4x51nch film, by setting the scanner 200 magnification to 32% (0.32x), the entire screen of the color original 2 is scanned with 512 scanning lines and stored in the IC memory 142. . At the same time, the simulation unit 110 simulates a printed image under the color separation conditions set in the masking circuit 40, the undercolor removal circuit 42, and the gradation correction circuit 44.

- If the image on the color monitor 152 is favorable, set the film 6 on the recording drum 7G and perform color separation work. In this case, the signal 188 is connected to the upper terminal (without passing through the gradation correction circuit 146) to perform color separation. If the image on the color monitor 152 is undesirable, adjust the tone correction circuit 146 to set favorable correction conditions, and then connect the switches 180 to 186 to the lower terminals to adjust the tone correction circuit. Color separation work is performed through 146.

If necessary, especially if the setting conditions of the masking circuit 40 are bad, after adjusting the masking circuit 40, perform the simulation again on the color monitor 152 as described above, and then perform the color separation work. It is preferable to do so.

(Effects of the Invention) As described above, according to the present invention, a printing simulation apparatus can be constructed without making any modifications to a conventional color scanner.

Moreover, since the signal from the color scanner is a signal after color training, so-called plate inspection work can be performed accurately without actually making separation plates.For example, after making separation plates, the process described in US Pat. The time and cost can be significantly reduced compared to inspecting a plate using a plate inspection apparatus such as that described in the 066 specification. Furthermore, since the output signal of the color calculation circuit including the masking circuit, undercolor removal circuit, etc. in the color scanner is used, it can also be used as a calibration condition setting device. Furthermore, since the printing simulation device according to the present invention shares many parts with the color scanner used for actual printing, not only can simulations be made accurately, but also
For example, the device can be manufactured at a lower cost than when a TV camera is used for leaping images.

Roughly speaking, when performing color separation, the colors can be separated through the gradation correction circuit of the simulation unit through a bypass.
It is not necessary to roughly add the obtained correction conditions to the gradation correction circuit of the scanner as in the case of a conventional independent type simulation device, and the workability is extremely high.

Note that the present invention is not limited to the embodiments described above, and can be modified in various ways without changing the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a printing simulation device according to the present invention, FIG. 2 is a signal diagram explaining sampling deviation, and FIG. 3 is a diagram explaining storage and reading into an IC memory. . 2... Color original 6... Film 20... Color scanner 30... Reading drum 32... Reading head 44... Gradation correction circuit 52... Channel selector 62... Dot generator 66 ...Recording head 70...Recording drum 110...Simulation unit 120.192
... Level adjuster 124 ... Averaging circuit 126 ... Address control circuit 144 ... D/A converter 146 ... Gradation correction circuit 147 ... Curve correction circuit 148 ... Color correction Circuit 150...Matrix circuit 152...Color monitor

Claims (1)

[Claims] In a printing simulation device that includes a color scanner and a simulation unit, the color scanner includes a color calculation circuit that includes at least a masking circuit, an undercolor removal circuit, and a gradation correction circuit, and simulates an image signal after passing through the color calculation circuit. The simulation unit is configured to output to the unit side, and the simulation unit converts yellow, magenta, cyan, and black image signals from the interface section, IC memory, color calculation circuit, and printing system into red, green, and blue image signals from the television system. A printing simulation characterized in that it is equipped with a conversion calculation circuit for conversion, a color monitor, etc., and a bypass is provided from the color scanner to the color calculation circuit of the simulation unit, so that color separation is possible through the color calculation circuit during color separation. Device.