JPS6323480A - Mask plate forming method and its forming equipment - Google Patents

Abstract

PURPOSE:To facilitate the registering of a halftone plate and a mask plate by applying filter processing to a binarizing image signal to generated an unsharp signal, binarizing the signal and exposing and recording a duplicate image on an unexposed film. CONSTITUTION:An output image signal of a gradation circuit (1st binarization circuit) 34 is inputted to a filter processing circuit in a peak intensifying circuit 35, from which the unsharp signal U being the arithmetic means between an image signal S and image signals of plural surrounding image elements is generated, the signal U is inputted to a 2nd binarization circuit 37. Laser light is subjected to on/off-control by a photomodulator 39 in an exposure recording section 43 based on the image data subjected to binarization, a duplicate image is exposed and recorded on the unexposed film 42, and a mask plate 7 is formed by a development section 44. In setting the threshold value of the 2nd binarization circuit 37 lower, the mask plate of a transparent region 14 of a slightly smaller size than that of a reflected original is formed and the registering is facilitated in overlapping the mask plate 7 and the halftone plate at the forming of a pattern plate.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for creating a mask plate used for masking a halftone plate including a picture area created by an image scanning/recording device such as a scanner, and the method thereof. Regarding the creation device.

(Prior art and its problems) As shown in FIG. 5, a printed matter 1 such as a flyer advertisement is printed with a mixture of characters 2 and pictures 3.

When the printing plate used for printing this type of printed matter 1 is created by photolithography, especially black and white (including doubleton, etc.)
When performing plate making, for example, prepare a character negative plate 4 exclusively for characters as shown in FIG. 6 and a pattern negative plate 5 exclusively for pictures as shown in FIG. are successively positioned and printed on another film so that they match, and the printed image is recorded on a metal plate or other plate surface coated with photosensitive liquid in advance, and this is developed. to obtain the desired printing plate.

By the way, the above-mentioned pattern plate 5 is created using a halftone plate 6 shown in FIG. 8 and a mask plate 7 shown in FIG. 9. In this case, the halftone plate 6 and the mask plate 7 are created as follows. That is, as shown in FIG. 10, a transparent sheet with a reflective original image 10 such as photographic paper pasted on a document holder placed at one image-forming coprecipitation position of the optical imaging system 9 of the plate-making camera 8. The sheet 11 is set, the unexposed film 12 is set in the film holder placed at the other coprecipitation position, the contact screen 13 is tightly attached in front of it, and the reflected original image 10 is illuminated from the front side (with the irradiation direction indicated by the arrow). (represented by the symbol X), the film 12 is subjected to camera shading, and this is developed to form a negative shading plate 6 shown in FIG.
Create. Next, the contact screen 13 is removed, another unexposed film 12 is set, and the reflective original image 10 is exposed to the camera while being illuminated from the back side (the direction of illumination is indicated by the arrow Y), and then developed. Then, a negative mask plate 7 shown in FIG. 9 is created.

In this case, the illumination light irradiated from the back side of the reflective original image 10 is reflected by the reflective original image 10, and is transmitted in other areas and bound onto the film 12, so that the mask plate 7
As shown in FIG. 9, the area corresponding to the reflective original image 10 becomes a transparent area 14 called "blank", and the other area 15 becomes an opaque area called "solid".

In addition, if you use a reflection original 10 that has not only a pattern but also a text pasted on it, or one in which both are aligned and overlapped, it is also possible to directly obtain a mask version with text. be. Next, the mask plate 7 is positioned so that its transparent area 14 matches the pattern area 16 of the halftone plate 6, and is superimposed on the halftone plate 6. This is set in a contact reversing printer and printed on a new film. After contact exposure and development, the pattern plate 5 shown in FIG. 7 is obtained (if a normal film is used, a positive image is obtained, and when a duplex film is used, a negative image is obtained). Note that instead of the above method, a method is also used in which reflected illumination and transmitted illumination are applied simultaneously or sequentially during camera transport, and the pattern plate 5 is directly created from the reflected original image 10 pasted on the transparent sheet 11. There is. However, in this method, since the pattern area 16 of the halftone plate 6 is shaded by the platemaking camera 8, the controllable range of gradation is limited and sharpness cannot be emphasized, making it difficult to achieve high-precision image quality. The problem was that it was insufficient to obtain the desired results.

In order to improve the image quality of the picture area 16, attempts have recently been made to create the halftone plate 6 using an image scanning/recording device such as a flat scanner. That is, the transparent sheet 11 on which the reflective original image 10 described above is pasted is set in the original image setting section of an image scanning/recording device such as a scanner, and the image is scanned from the surface side of the original image by the same device to be electronically recorded. Is there a net?
The duplicated image is exposed and recorded on an unexposed film, and the exposed film is developed to create a halftone plate 6 (not shown in FIG. 8). In this case, the mask version 7 is similar to the conventional one.
It is created using a photolithography camera 8 (FIG. 10). However, in this method, the magnification and distortion rate of the reproduced image produced by the image scanning/recording device do not exactly match the magnification and distortion rate of the reproduced image produced by the photomechanical camera, so the mask plate 7 is placed on the halftone plate 6. When superimposed on
The transparent area 14 and the pattern area 16 do not completely match, and a slight positional deviation occurs between them, resulting in a highly accurate pattern plate 5.
A new problem arises in that it is not possible to create .

Therefore, in order to solve the above problem, the inventor of the present application improved the conventional flat scanner to create a halftone plate 6 that is electronically shaded, and a mask that dimensionally matches the halftone plate 6. We have developed a mask plate making device that enables the creation of plate 7 (Japanese Patent Application No. 126676/1983). When creating the halftone plate 6, this mask plate making device is used in the same manner as a normal flat scanner. That is, a reflective original image pasted on a transparent sheet is image scanned from the front side of the original image, a shaded duplicate image is exposed and recorded on an unexposed film, and this exposed film is developed to create a halftone plate 6. do. On the other hand, when creating the mask plate 7, transmitting illumination is applied to the transparent sheet on which the reflective original image is pasted from the back side, and the image is scanned from the front side of the original image, and the obtained image signal is used as the signal of the transmitted light area. A voltage value intermediate between the voltage value and the signal voltage value of the non-transmitted light area is used as a threshold value to perform binarization processing, and using the binarized image signal, a duplicate image is exposed and recorded on an unexposed film, The exposed film is developed to create a mask plate. According to this mask plate making device,
Since the mask plate 7 is created by electronically shading the same way as the halftone plate 6, the magnification of the duplicate image is exactly the same for the mask plate 7 and the halftone plate 6, and distortion occurs in the duplicate image. Even if they are, they will be the same in terms of definition, and therefore the transparent area 14 of the mask plate 7 and the pattern area 16 of the halftone plate 6 can be made to perfectly match, and a highly accurate pattern plate 5 can be created.

However, when the halftone plate 6 and the mask plate 7 are created using this mask plate making device, the transparent area 14 of the mask plate 7 and the pattern area 16 of the halftone plate 6 are created with dimensions that match too completely. Therefore, in the process of creating the pattern plate 5 using a contact printer, even the slightest positional deviation is not allowed when overlapping the images 6 and 7, making it extremely difficult to register the images 6 and 7. arise. Further, with the above-mentioned mask plate creating apparatus, it is impossible to create a mask plate 7 in which a border can be added to the periphery of the picture area of the picture plate 5.

(Purpose of the Invention) This invention was made to solve the above problem, and it is possible to accurately mask a shading plate created by electronic shading, and to create a highly accurate pattern plate with excellent image quality. To create a mask plate, which can easily register the halftone plate and the mask plate when creating the pattern plate, and which can create a mask plate that can add a border to the periphery of the pattern area of the pattern plate. and to provide a creation device.

(Means for achieving the object) The first invention, a method for creating a mask plate, scans a reflective original pasted on a transparent sheet from the front side of the original, and transfers the shaded duplicate image to an unexposed film. Record the exposure to
A method for creating a mask plate for masking a halftone plate obtained by developing this exposed film, the method comprising:
In order to achieve the above objective, transmitted illumination is applied from the back side of the transparent sheet on which the reflective original image is pasted, and the image is scanned from the front side of the original image, and the obtained image signal is compared with the signal voltage value of the transmitted light area. A voltage value between the signal voltage values in the transmitted light region is used as a threshold value to perform binarization processing, and the binarized image signal is subjected to filter processing to generate that image signal and image signals of multiple pixels around it. Create an unsharp signal that is averaged, and apply the unsharp signal to a predetermined voltage value between the signal voltage value corresponding to the transmitted light region and the signal voltage value corresponding to the non-transmitted light region as a threshold value. A duplicate image is exposed and recorded on an unexposed film using the binarized image signal, and developed to create a mask plate.

The mask plate making device which is the second invention is a device used in the above-mentioned mask plate making method, that is, the image is scanned from the surface side of the original image on a reflective original pasted on a transparent sheet, and a shaded copy is obtained. This is a mask plate making device for recording an image on an unexposed film and masking a halftone plate obtained by developing the exposed film. an original image setting section in which the attached transparent sheet is set with the original screen facing downward; a light source disposed above the original image setting section; an image scanning section disposed below the original image setting section; A first binarization process that binarizes the image signal obtained by the image scanning of the scanning unit using a voltage value intermediate between the signal voltage value of the transmitted light region and the signal voltage value of the non-transmitted light region as a threshold. circuit, and an unsharp signal that filters the image signal binarized by the first binarization circuit to create an unsharp signal in which the image signal and a plurality of surrounding image signals are averaged. a sharp signal generating circuit; and a step for binarizing the unsharp signal using a predetermined voltage value between the signal voltage value corresponding to the transmitted light region and the signal voltage value corresponding to the non-transmitted light region as a threshold value. 2 binarization circuit, and the second
and an exposure recording section that records a duplicate image on an unexposed film using the image signal binarized by the binarization circuit.

(Example) Figure 1 is a schematic configuration diagram showing the input section of a mask plate creation device that also serves as an image scanning/recording device (so-called flat scanner), and Figure 2 is a diagram showing the signal processing section and output of the same device. FIG. The device referred to herein as a mask printing device is a well-known flat scanner.

As shown in FIG. 1, an original image setting section 21 made of transparent glass or the like is provided on the upper surface of the main body 20 of the apparatus. A light source 22 configured with a lamp or the like for illuminating the original image setting section 21 from above is located above the original image setting section 21.
is arranged, and the apparatus main body 20 below the original image setting section 21
Inside, the original picture set on the original picture setting section 21 (for example, the reflective original picture 10 and the transparent sheet 11 on which it is pasted) are shown.
) and an image scanning section 24 are provided. The image scanning section 24 has a line sensor 25 composed of a light receiving element such as a COD, and a part of the light reflected or transmitted by the original image set on the original image setting section 21 is passed through the slit plate 26.
It is configured so that the light passes through the line, is reflected by mirrors 27, 28, and 29, and is imaged onto the line sensor 25 by the optical lens system 30. In this case, the light source 23 and the slit plate 26
A mirror 27 is held by a traveling body 31 so as to be movable in the horizontal direction (sub-scanning direction) in FIG. The image data is obtained by scanning the entire surface of the original image by moving the traveling body 31 in the sub-scanning direction (rightward in FIG. 1) while scanning in the direction perpendicular to the plane of the drawing.

The analog image signal having a voltage value corresponding to the density value of each pixel output from the line sensor 25 is serially inputted to an A/D conversion circuit 32 and converted into a digital signal, as shown in FIG. The shading correction circuit 33
After shading correction in , gradation circuit 3
4.

When the selection mode on the operation panel is switched to "shading plate creation mode", the gradation circuit 34
It is configured so that the characteristics of the output voltage with respect to the input voltage can be freely adjusted by operating the operation panel. for example,
As shown in the gradation curve A of FIG. 3, fine concentration control can be performed by adjusting the characteristics of the output voltage with respect to the input voltage. Also, the selection mode is "Mask version creation mode"
3, the gradation curve is adjusted as shown by characteristic curve B in FIG.

That is, the adjustment is made such that when the input voltage exceeds a predetermined value M, a signal of a predetermined high voltage rHJ is output, and when the input voltage is less than a predetermined value M, a signal of a predetermined low voltage rLJ is output. At this time, the gradation circuit 34 functions as a first binarization circuit (details thereof will be described later). The signal output from the gradation circuit 34 is input to the sharpness enhancement circuit 35.

The sharpness emphasizing circuit 35 is configured to perform different operations depending on whether the selection mode is switched to the "halftone plate creation mode" or the case where the selection mode is switched to the "mask plate creation mode." Selection mode is "shading version creation mode"
If the mode is switched to , the same operation as normal scanning is performed. That is, the image signal corresponding to the center pixel inputted from the gradation circuit 34 is used as the sharp signal S, and this sharp signal S is inputted to a filter processing circuit for creating an unsharp signal (for example, Japanese Patent Application No. 59-239282). Then, an unsharp signal U is created by adding and averaging the image signals of the center pixel and the surrounding pixels.
The calculation (SU) (K: coefficient) is performed to create an image signal subjected to sharpness intensity processing. This image signal is output to the magnification adjustment circuit 36 at the next stage.

On the other hand, when the selection mode is switched to "mask plate creation mode", the filter processing circuit in the sharpness emphasizing circuit 35 creates an unsharp signal U, and this unsharp signal U is Emphasis processing i.e. S
The signal is output to the second binarization circuit 37 as it is without being subjected to the arithmetic processing of +K (S-U). That is, in this case, the sharpness enhancement circuit 35 functions as an unsharp signal generation circuit.

The second binarization circuit 37 converts the unsharp signal U into
Binarization processing is performed using a predetermined voltage value (the details of which will be described later) between the signal voltage value corresponding to the transmitted light region and the signal voltage value corresponding to the non-transmitted light region as a threshold value. In this case, the predetermined voltage value is configured to be adjustable by operating an external operation panel. The image signal subjected to the binarization process by the binarization circuit 37 is output to the magnification adjustment circuit 36 at the next stage.

The magnification adjustment circuit 36 performs data processing for magnification adjustment on the image signal output from the sharpness emphasizing circuit 35 and the image signal output from the second binarization circuit 37, respectively, and performs data processing on the image signal output from the sharpness enhancement circuit 35 and the image signal output from the second binarization circuit 37 to generate halftone dots at the next stage. It is configured to output to circuit 38 .

The halftone dot generation circuit 38 controls the optical modulator 39 so that halftone dots are formed according to the input data.
Controls on/off by

The laser beam, which is on/off controlled by the optical modulator 39, is transmitted in the main scanning direction by the galvanometer 41 (left and right directions in Fig. 2).
While being scanned, the unexposed film 42 is transported in the sub-scanning direction (perpendicular to the paper surface in the second figure) by a feed roller (not shown), and a duplicate image is illuminated and shaded on the film 42. Exposure is recorded. In this case, the halftone dot generation circuit 38, the laser device 40. Optical modulator 39. An exposure recording section 43 is constituted by a galvanometer mirror 41 and the like.

An exposed film 42 is placed on the side of this exposure recording section 43.
A developing section 44 for developing is provided. The exposed film 42 may be carried into the developing section 44 manually, or may be automatically carried in using a conveyance device (not shown).

Operation Next, the procedure for creating the halftone plate 6 (FIG. 8) and the mask plate 7 (FIG. 9) using the above-mentioned apparatus will be explained.

1. Preparation of wA shaded plate First, the shaded plate 6 (FIG. 8) is prepared as follows. This procedure is similar to the procedure for creating a halftone plate using a normal scanner.

■ First, change the selection mode to "shading plate creation mode" and initialize the mask plate creation device. That is,
Gradation and sharpness emphasis due to setup work 9
Set the magnification etc. to desired values.

In this case, the gradation is set so that, for example, gradation curve A shown in FIG. 3 is obtained.

■ Next, as shown in FIG. 1, the transparent sheet 11 on which the reflective original image 10 such as photographic paper is pasted is set in the original image setting section 21 with the original surface of the reflective original image 10 facing downward, and the original image is placed on top of it. Put on a cover (not shown).

■ Turn on the internal light source 23 (at this time, the external light source 22 is off) and press the scanning start button.

However, it is preferable that the point pairing of the internal light source 23 be configured to be performed automatically in conjunction with switching the selection mode to the "shading plate creation mode".

When the scanning start button is pressed, the main scanning by the line sensor 25 starts from the origin position, and the traveling body 31 starts moving in the sub-scanning direction (rightward in FIG. 1), and sets the original image in the original setting section 21. transparent sheet 11
and the image data of the original image 10 are sequentially read by the licensor 25.

At this time, the light emitted from the internal light source 23 and reflected by the original screen is incident on the line sensor 25, so the output signal of the line sensor 25 is that of the pattern drawn on the original image 10, the transparent sheet 11, etc. An analog signal having a voltage value corresponding to the concentration value is set to 1.

The output signal of this line sensor 25 is transmitted to the A/D conversion circuit 3.
2, the signal is converted into a digital signal, subjected to shading correction by a shading correction circuit 33, and then input to a gradation circuit 34. Gradation circuit 3
4, the output voltage value is adjusted so that delicate yArei control is performed according to the gradation curve A in FIG. The output signal of this gradation circuit 34 is input to the sharpness emphasizing circuit 35, which uses the sharp signal S and the unsharp signal U created by the filter processing circuit to
K (S-LJ) calculation processing (sharpness emphasis processing) is performed. The image signal subjected to sharpness enhancement processing in this manner is input to the magnification adjustment circuit 36 and subjected to data processing for magnification adjustment, and then input to the halftone dot generation circuit 38 of the exposure recording section 43. The exposure recording section 43 controls the light modulator 39 based on the data input to the halftone dot generation circuit 38 to turn on and off the laser light projected from the laser device 40.
The laser beam is caused to main-scan on the unexposed film 42 that is transported in the sub-scanning direction, and a shaded duplicate image is exposed and recorded on the film 42. The film 42 on which the duplicate image has been exposed and recorded is sent to the developing section 44, where it is developed and a halftone plate 6 shown in FIG. 8 is created.

2. Creation of a mask version Next, a mask version 7 (FIG. 9) is created. The procedure is as follows.

■ First, switch the selection mode to "mask plate creation mode". As a result, the gradation circuit 34
The circuit 34 is set to function as a value converting circuit, and thus the circuit 34 is adjusted so as to obtain the gradation curve B shown in FIG. Further, the sharpness enhancement circuit 35 is set to function as an unsharp signal generation circuit.

(2) Next, the internal light source 23 shown in FIG. 1 is turned off, and the external light source 22 is turned on instead. However, the above operation is
It is preferable to configure this so that when the selection mode is switched to the "mask plate creation mode", this is automatically performed in conjunction with the switching operation.

■ Also, the original cover that was placed on the transparent sheet 11 (
(not shown) is removed, and a translucent diffuser plate 45 shown in FIG. 1 is placed on the transparent sheet 11 instead. This diffuser plate 45
serves to diffuse the light projected from a point light source 22 such as a lamp, send it to the transparent sheet 11 side, and enter the light into the optical path of the input optical system via the transparent sheet 11.

■ After this, press the scanning start button.

When the scanning start button is pressed, the main scanning by the line sensor 25 starts again from the origin position, the traveling body 31 starts moving in the sub-scanning direction (rightward in Figure 1), and the image data is transferred to the line sensor. 25 are read sequentially. At this time, the light projected from the external light source 22 is reflected upward in the area of the reflective original image 10, is transmitted in other areas, and the light that passes through the slit 26 is imaged on the line sensor 25. FIGS. 4(a) and 4(b) are diagrams schematically showing the relationship between the transparent sheet 11 to which the reflective original image 10 is attached and the light distribution of transmitted light with respect to the original. As can be seen from the figure, the transmitted light is reflected from the original image 10
It is distributed in an area other than the area corresponding to , that is, an area where only the transparent sheet 11 exists. Therefore, the output signal of the line sensor 25 has a low voltage in the section where the reflective original image 10 is scanned, and the output signal of the transparent sheet 11 other than that is a low voltage.
The voltage is high in the area where the area where only the rays are present is being scanned.

The output signal of this line sensor 25 is sent to the A/D conversion circuit 32.
．． The signal is input to the gradation circuit 34 via the shading correction circuit 33. As mentioned above, the gradation circuit 34 has the characteristic of gradation curve B (FIG. 3), that is, it has a voltage value intermediate between the signal voltage value in the transmitted light region and the signal voltage value in the non-transmitted light region. The threshold value is 2 (functions as a first binarization circuit that performs self-generating processing).

Therefore, the gradation circuit (first binarization circuit)
The output signal 34 is a constant low voltage rLJ signal in the area where the reflective original image 10 is scanned, and is a constant high voltage rHJ signal in the area where only the transparent sheet 11 is present. becomes.

The output signal of the gradation circuit 34 is input to the sharpness enhancement circuit 35. As described above, the sharpness enhancement circuit 35 is set to function as an unsharp signal generation circuit by switching the selection mode, so that the input image signal is processed by the filter processing circuit within the sharpness enhancement circuit 35. An unsharp signal U is created by averaging the image signal S and the image signals of a plurality of surrounding pixels. FIG. 4(C) shows the unsharp signal U created in this way.

This unsharp signal U is sent to the second binarization circuit 3 in the next stage.
7 is input. In the second binarization circuit 37, the unsharp signal U is intermediate between the rHJ level (i.e., the signal voltage value corresponding to the transmitted light region) and the "shi" level (i.e., the signal voltage value corresponding to the non-transmitted light region). The unsharp signal U is binarized using a predetermined voltage value located at the threshold value (see FIG. 4(C)) to create a 2wi signal as shown in FIG. 4(d). This binary signal T becomes a signal of a constant high voltage rHJ in a section corresponding to a voltage section higher than the threshold value (predetermined voltage value) of the unsharp signal U, and the threshold value of the unsharp signal U becomes a signal of a constant high voltage rHJ. In a section corresponding to a voltage section lower than (predetermined voltage value), the signal becomes a constant low voltage "L". At this time, the voltage value of the low voltage "shi" commands 0% shading in the subsequent exposure recording section 43, and the voltage value of the high voltage rHJ commands 100% shading. selected. By the way, the predetermined voltage value corresponding to the threshold value (FIG. 4(C)) can be adjusted by operation from an external operation panel.
Therefore, by changing this threshold, 2gf
The length of the rLJ level section of the i-coded signal T can be adjusted. That is, if the threshold value (predetermined voltage value) is set to a voltage value exactly between the rHJ level and the rLJ level of the unsharp signal U, the section length of the rLJ level of the binarized signal T can be set to the non-transmitted light region. (an area corresponding to the area of the original image 10 in FIG. 4(a)). Then, by moving the threshold value (predetermined voltage value) from the intermediate voltage value closer to the rLJ level of the unsharp signal U, the section length of the rLJ level of the two-field signal T can be shortened accordingly, and vice versa. Nishiki lit! If the (predetermined voltage value) is brought closer to the "H" level of the uncitobe signal U,
Correspondingly, the section length of the rLJ level of the binarized signal T can be improved.

In the example of FIG. 4, since the threshold value is set lower than the intermediate voltage value of the unsharp signal U, I'L of the binarized signal T
The section length of the J level is shorter than the section length of the non-transmitting light area (an area corresponding to the area of the original image 10 in FIG. 4(a)).

This binary signal T is input to the next stage magnification adjustment circuit 36 and subjected to data processing for magnification adjustment.
3 is input to the halftone dot generation circuit 38.

In the exposure recording section 43, the laser beam projected from the laser device 40 is controlled on and off by the light modulator 39 based on the binarized image data, and is scanned onto the unexposed film 41. .

As a result, 0 in the rLJ level section of the binarized signal T.
%, and in the rHJ level section of the binarized signal T, a duplicate image that is shaded 100% will be exposed and recorded on the unexposed film 42. The film 42 on which the binarized duplicate image has been exposed and recorded is carried into the developing section 44, where it is developed and a mask plate 7 shown in FIG. 9 is created. FIG. 4(e) shows the shaded state of the mask plate 7, where the region 14 corresponding to the rLJ level of the binarized signal T is shaded at 0%, so-called "
It is a transparent area called "Nuke", and the binary signal T
The area 15 corresponding to the rHJ level is shaded to 100% and is an opaque area called "solid". In the example shown in FIG. 4, the rLJ level interval length of the binarized signal T is shorter than the interval length of 100 reflection original images, so the transparent area 14 of the mask plate 7 is
The size is smaller than 0.

The thus created mask plate 7 (Fig. 9) is positioned and superimposed on the already created halftone plate 6 (Fig. 8),
By setting this in a contact printer and exposing it to the unexposed film, a picture board 5 shown in FIG. 7 is created.

Effects of the Embodiment As described above, in this embodiment, the shading on the halftone plate 6 shown in FIG. can be made into high-quality images. In addition, like the halftone plate 6, the mask plate 7 is created by electronically shading using the mask plate creation equipment, so the magnification and distortion rate of the reproduced image are different from the mask plate 7 and the halftone plate 6. This makes it possible to create a highly accurate pattern board 5. Moreover, when creating the mask plate 7, the second binarization circuit 37
The dimensions of the transparent area 14 of the mask plate 7 can also be adjusted by adjusting the threshold value (predetermined voltage value) of . For example, as shown in FIG. 4, by setting the threshold value lower than the intermediate voltage value of the unsharp signal U, it is possible to create a mask plate 7 having a transparent area 14 slightly smaller in size than the reflective original 10. In this case, when creating the pattern board 5 using a contact printer, the mask plate 7 and the shaded plate 6 are
When overlapping the transparent area 14 and the pattern area! ii! c1
6 can be easily registered, and the workability of plate making can be improved. Furthermore, if the threshold value (predetermined voltage value) of the second binarization circuit 37 is set higher than the intermediate voltage value of the unsharp signal U, the transparent area 14 with dimensions slightly larger than the reflection original image 10 can be created. It is possible to create a mask version 7 having the following characteristics. In this case, the mask plate 7 and the halftone plate 6 are used to create a picture board 5 in which a border (for example, a mesh with a 20% gradation density: can be changed arbitrarily) is created around the picture area. becomes possible.

Application Example In the above embodiment, a point light source 22 such as a lamp is used as a light source for illuminating the reflective original image 10 from the back side, but a surface light source (not shown) may be used instead of the point light source 22. . When a surface light source is used, illumination unevenness can be reduced compared to the point light source 22, so the diffuser plate 45 can be omitted. However, in order to further eliminate uneven illumination, the surface light source and the diffuser plate 45 may be used together.

Further, in the above embodiment, the explanation has been given of a monochrome apparatus in which the original image is black and white, but the present invention can also be applied to cases where the original image is in color, and can also be applied to a color apparatus.

Furthermore, the gradation circuit 34 may be arranged in parallel with a gradation-dedicated circuit and a binarization circuit (line drawing circuit), and may be used selectively.

Furthermore, instead of the transparent sheet 11, a character positive plate as shown in FIG. 6 may be used, and the photographic original 10 may be pasted onto this.

(Effects of the Invention) As described above, according to the mask plate making method and its making device of the present invention, it is possible to create a mask plate that can mask a halftone plate made by electronic tethering with good viscosity. It is possible to create a pattern plate with excellent image quality, and when creating a pattern plate, it is easy to register the halftone plate and the mask plate, and the mask plate can add a border around the pattern area of the pattern plate. The effect is that it also becomes possible to create .

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing the input section of a mask plate making device which is an embodiment of the present invention, FIG. 2 is a schematic block diagram showing the signal processing section and output section of the same device, and FIG. 3 is a gradation circuit. Figure 4 is a schematic diagram showing the principle of making a mask plate, Figure 5 is a plan view showing an example of printed matter, and Figure 6 is a diagram showing the relationship between input voltage and output voltage. Fig. 7 is a plan view of the picture plate, Fig. 8 is a plan view of the shaded plate, Fig. 9 is a plan view of the mask plate, Fig. 1 is a plan view of the letter plate;
FIG. 0 is a schematic configuration diagram of a camera for plate making. 6...Shaded version, 7...Mask version, 10.
...Reflection original picture, 11...Transparent sheet, 22...
- Light source, 24... Image scanning section, 34...
gradation circuit (first binarization circuit), 35... sharpness enhancement circuit (unsharp signal creation circuit), 37... second binarization circuit,

Claims (3)

[Claims] (1) Scanning the reflective original pasted on a transparent sheet from the front side of the original, recording the shaded duplicate image on unexposed film, and developing the exposed film. A method for creating a mask plate for masking a plate, in which transmitted illumination is applied from the back side of a transparent sheet to which the reflective original image is pasted, the image is scanned from the front side of the original image, and the obtained image signal is transmitted. Binarization processing is performed using a voltage value between the signal voltage value in the light region and the signal voltage value in the non-transmitted light region as a threshold, and the binarized image signal is filtered to separate the image signal and its An unsharp signal is created by averaging the image signals of multiple surrounding pixels, and the unsharp signal is set to a predetermined value between the signal voltage value corresponding to the transmitted light area and the signal voltage value corresponding to the non-transmitted light area. A method for creating a mask plate, in which a voltage value of 1 is used as a threshold value to perform binarization processing, and using the binarized image signal, a duplicate image is exposed and recorded on an unexposed film and developed to create a mask plate. (2) The image of the reflective original pasted on a transparent sheet is scanned from the front side of the original image, the shaded duplicate image is exposed and recorded on unexposed film, and the exposed film is developed to create the shaded area. A mask plate creation device for masking a plate, the device comprising: an original image setting section in which a transparent sheet with a reflective original image pasted is set with the original screen facing downward; and a light source disposed above the original image setting section. an image scanning section disposed below the original image setting section; and an image signal obtained by the image scanning of the image scanning section,
The first step is to perform binarization processing using a voltage value intermediate between the signal voltage value of the transmitted light region and the signal voltage value of the non-transmitted light region as a threshold value.
filtering the image signal binarized by the digitization circuit and the first binarization circuit to create an unsharp signal in which the image signal and a plurality of surrounding image signals are averaged; an unsharp signal generating circuit that performs binarization processing on the unsharp signal using a predetermined voltage value between the signal voltage value corresponding to the transmitted light region and the signal voltage value corresponding to the non-transmitted light region as a threshold value; a second binarization circuit that performs the binarization process, and an exposure recording unit that records a duplicate image on an unexposed film by exposure using the image signal binarized by the second binarization circuit. Creation device. (3) The mask plate making apparatus according to claim 2, wherein the second binarization circuit is configured such that a predetermined voltage value corresponding to the threshold value thereof can be changed by external operation.