JPH0518508B2 - - Google Patents

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 a method for creating a mask plate using the method. Regarding the creation device.

(Prior art and its problems) As shown in Figure 5, printed materials such as flyer advertisements 1
A mixture of letters 2 and pictures 3 are printed on the .
When creating a printing plate used for printing this type of printed matter 1 by photolithography, especially when performing black-and-white (including doubleton, etc.) platemaking, for example, a character negative exclusively for characters as shown in FIG. A printing plate 4 and a pattern negative printing plate 5 exclusively for the pattern as shown in FIG.
The film copy image is printed and recorded on the surface of a metal plate or other plate material coated with a photosensitive liquid in advance, and then developed to obtain a 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 joint position of the optical imaging system 9 of the plate-making camera 8. Set the sheet 11, and place the unexposed film 1 in the film holder placed at the other yoke position.
2, the contact screen 13 is placed in close contact with the front of the contact screen 13, and the reflected original image 10 is illuminated from the front side (the direction of irradiation is indicated by the arrow X), but the film 12 is shaded and photographed by the camera, which is then developed and processed. A negative halftone plate 6 shown in FIG. 8 is created. Next, the contact screen 13 is removed, another unexposed film 12 is newly set, the reflected original image 10 is photographed from the back side with a camera under transmitted illumination (the irradiation direction is indicated by the arrow Y), and this is developed. 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,
Since other areas are transmitted through and formed on the film 12, the area of the mask plate 7 corresponding to the reflected original image 10 becomes a so-called "blank" transparent area 14, as shown in FIG. Area 1 of
5 is an opaque area called "solid". Note that if the reflective original 10 is used that has not only a pattern but also a text pasted thereon, or one in which both are aligned and overlapped, it is also possible to directly obtain a mask plate with text. Next, the mask plate 7 is positioned so that its transparent area 14 coincides with the pattern area 16 of the halftone plate 6, and the halftone plate 6 is
This is placed on a contact reversing printer, and a new film is exposed and developed to obtain the pattern plate 5 shown in Figure 7 (if a normal film is used, it will be positive; if a duplex film is used, it will be a positive image). negatives are obtained respectively). Note that instead of the above method, there is also a method of directly creating the pattern plate 5 from the reflective original image 10 pasted on the transparent sheet 11 by applying reflected illumination and transmitted illumination simultaneously or sequentially during camera photography. . 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 front side of the original image by the device to be electronically shaded. The duplicated image is exposed and recorded on an unexposed film, and the exposed film is developed to create a halftone plate 6 shown in FIG. In this case, the mask plate 7 is created using a photomechanical camera 8 (FIG. 10), as in the prior art. 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 superposed on each other, the transparent area 14 and the pattern area 16 do not completely match, and a slight positional deviation occurs between them, causing a new problem in that a highly accurate pattern board 5 cannot be created.

Therefore, in order to solve the above problem, the inventor of the present application improved the conventional flat scanner to create an electronically shaded halftone plate 6 and a mask dimensionally matching the halftone plate 6. Developed a mask plate making device that made it possible to create plate 7 (patent application 1986).
−126676). 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 creation device, since the mask plate 7 is created by electronically shading the same as the halftone plate 6, the magnification of the duplicated image is exactly the same between the mask plate 7 and the halftone plate 6. Therefore, even if the duplicated image is distorted, it will be the same for both plates, so mask version 7
The transparent area 14 of the screen and the pattern area 16 of the halftone plate 6 can be made to completely match, and the pattern plate 5 with high precision 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. In order to
In the process of creating the pattern plate 5 using a contact printer, even the slightest positional deviation is not allowed when the plates 6 and 7 are overlapped, resulting in the inconvenience that registering the plates 6 and 7 becomes extremely difficult. In addition, with the above-mentioned mask plate making apparatus, it is impossible to produce a mask plate 7 that can add a border 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. A method for creating a mask plate for masking a halftone plate obtained by recording exposure on a film and developing this exposed film, in which the reflective original image is pasted in order to achieve the above-mentioned purpose. Transmitted illumination is applied from the back side of the transparent sheet, the image is scanned from the front side of the original image, and the voltage value between the signal voltage value in the transmitted light area and the signal voltage value in the non-transmitted light area is set as a threshold value for the obtained image signal. Then, the binarized image signal is subjected to filter processing to create an unsharp signal in which the image signal and the image signals of a plurality of surrounding pixels are added and averaged, and the unsharp signal is Binarization processing is performed 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, and the binarized image signal is used. The duplicated image is exposed and recorded on unexposed film 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 in which the image signal obtained by the image scanning of the scanning unit is binarized using a voltage value intermediate between the signal voltage value of the transmitted light area and the signal voltage value of the non-transmitted light area as a threshold value. and an unsharp signal for filtering the image signal binarized by the first binarizing circuit to create an unsharp signal in which the image signal and a plurality of peripheral image signals are added and averaged. creation circuit and
a second binarization circuit that binarizes 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; , an exposure recording section that records a duplicate image on an unexposed film by exposure using the image signal binarized by the second binarization circuit.

(Example) Configuration of mask plate making device Fig. 1 is a schematic configuration diagram showing the input section of the mask plate making device which also serves as an image scanning/recording device (so-called flat scanner), and Fig. 2 shows the signal processing of the device. FIG. 3 is a schematic configuration diagram showing a section and an output section. 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 composed of a lamp or the like for illuminating the original image setting section 21 from above is disposed above the original image setting section 21, and an original image setting section 21 is provided in the apparatus main body 20 below the original image setting section 21. The original picture set on the section 21 (for example, the reflective original picture 10 and the transparent sheet 1 on which it is pasted)
1) A light source 23 composed of a halogen lamp or the like for illuminating the image from below, 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 CCD, and passes a part of the light reflected or transmitted by the original image set on the original image setting section 21 through a slit plate 26. Reflected by mirrors 27, 28, 29 and optical lens system 3
0, the image is formed on the line sensor 25. In this case, the light source 23, the slit plate 26, and the mirror 27 are held movably in the horizontal direction (sub-scanning direction) in FIG. By moving the traveling body 31 in the sub-scanning direction (to the right in Fig. 1) while scanning in the main scanning direction (perpendicular to the paper surface in Fig. 1) using the sensor 25, the entire surface of the original image is scanned and image data is generated. It is configured so that it can be obtained.

An analog image signal having a voltage value corresponding to the density value of each pixel output from the line sensor 25 is inputted in time series to an A/D conversion circuit 32 and converted into a digital signal, as shown in FIG. After being converted and subjected to shading correction in a shading correction circuit 33, it is configured to be input to a gradation circuit 34.

The gradation circuit 34 is configured such that when the selection mode on the operation panel is switched to "shading plate creation mode", the characteristics of the output voltage with respect to the input voltage can be freely adjusted by operating the operation panel. Ru. For example, as shown in the gradation curve A of FIG. 3, fine density 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 so that when the input voltage exceeds a predetermined value M, a predetermined high voltage "H" signal is output, and when the input voltage is less than a predetermined value M, a predetermined low voltage "L" signal 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 sent to the sharpness enhancement circuit 3.
5 is input.

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." When the selection mode is switched to the "shading plate creation mode", the same operation as in normal scanning is performed. That is, the gradation circuit 3
The image signal corresponding to the center pixel input from 4 is used as a sharp S signal, and this sharp signal S is input to a filter processing circuit (for example, Japanese Patent Application No. 59-239282) for creating an unsharp signal.
An unsharp signal U is created by adding and averaging the image signals of the center pixel and the surrounding pixels, and S+K (S-U) (K: coefficient) is applied to both signals S and U.
The following calculations are 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", an unsharp signal U is created by the filter processing circuit in the sharpness emphasizing circuit 35, and this unsharp signal U is processed by the sharpness emphasizing process described above. That is, the signal is output to the second binarization circuit 37 as it is without being subjected to the calculation process of S+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 outputs an unsharp signal U
On the other hand, binarization processing is performed using a predetermined voltage value (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 receives the image signal output from the sharpness enhancement circuit 35 and the second binarization circuit 37.
Data processing for magnification adjustment is performed on the image signals outputted from each of
is configured to output to .

The halftone dot generation circuit 38 controls the light modulator 39 so that halftone dots are formed according to the input data, that is, the light modulator 39 controls on/off of the laser light projected from the laser device 40. . The laser beam controlled on and off by the optical modulator 39 is scanned by a galvanometer 41 in the main scanning direction (horizontal direction in FIG. 2) and scanned in the sub-scanning direction (second
Unexposed film 4 being transported in a direction perpendicular to the plane of the drawing
2 and a shaded duplicate image is exposed and recorded on the film 42. In this case, the halftone dot generation circuit 38, the laser device 40, the optical modulator 39,
An exposure recording section 43 is constituted by a galvanometer mirror 41 and the like. A developing section 44 for developing the exposed film 42 is provided at a side of the exposure recording section 43. The exposed film 42 may be carried into the developing section 44 manually, or may be automatically carried using a conveying device (not shown).

Operation Next, using the above device, shaded plate 6 (Fig. 8)
The procedure for creating the mask plate 7 (FIG. 9) will be explained.

1 Creating a shaded plate First, create a shaded plate 6 (Fig. 8) as follows. This procedure is similar to the procedure for creating a halftone plate using a normal scanner.

First, the selection mode is switched to "shading plate creation mode" and the mask plate creation apparatus is initialized. That is, the gradation, sharpness emphasis, magnification, etc. are set to desired values through a setup operation. 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 to which the reflective original image 10 is pasted, such as photographic paper, 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 cover is placed over it. (not shown).

Turn on the internal light source 23 (at this time, turn on the external light source 2
2 is off) and press the scanning start button. However, it is preferable that the internal light source 23 be turned on automatically in conjunction with switching the selection mode to the "shading plate creation mode".

When the scanning start button is pressed, main scanning by the line sensor 25 is started from the origin position, and the traveling body 31 is moved in the sub-scanning direction (first
The transparent sheet 11 set in the original image setting section 21 and the image data of the original image 10 are sequentially read by the line sensor 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 obtained. The output signal of this line sensor 25 is
After being converted into a digital signal by the A/D conversion circuit 32 and subjected to shading correction by the shading correction circuit 33, the gradation circuit 34
is input. In the gradation circuit 34, the output voltage value is adjusted in accordance with the gradation curve A shown in FIG. 3 so as to perform fine density control. The output signal of this gradation circuit 34 is input to the sharpness emphasizing circuit 35, and the sharpness signal S
Then, an arithmetic process (sharpness enhancement process) of S+K(S-U) is performed using the unsharp signal U created by the filter processing circuit. 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 optical modulator 39 based on the data input to the halftone dot generation circuit 38 to turn on/off the laser beam projected from the laser device 40.
OFF control, and the laser beam is caused to main-scan on the unexposed film 42 that is transported in the sub-scanning direction,
The 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 mask plate Next, mask plate 7 (Figure 9) is created. The procedure is as follows.

First, change the selection mode to "mask version creation mode"
Switch to As a result, the gradation circuit 34 is set to function as a first binarization circuit, that is, the circuit 34 is adjusted so as to obtain the gradation curve B shown in FIG. 3. Further, the sharpness enhancement circuit 35 is set to function as an unsharp signal generation circuit.

Next, the internal light source 23 shown in FIG. 1 is turned off, and the external light source 22 is turned on instead. However, it is preferable that the above operation be configured to be automatically performed in conjunction with the switching operation when the selection mode is switched to the "mask plate creation mode".

Further, the original cover (not shown) placed on the transparent sheet 11 is removed, and a translucent diffuser plate 45 shown in FIG. 1 is placed on the transparent sheet 11 instead. This diffuser plate 45 diffuses the light projected from the point light source 22 such as a lamp, and
1 side, and enters 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 is started again from the origin position, and the traveling body 31 starts moving in the sub-scanning direction (to the right in Figure 1), and the image data is displayed as a line. The sensor 25 sequentially reads the data. 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. 4a and 4b are diagrams schematically showing the relationship between the transparent sheet 11 to which the reflective original image 10 is pasted and the light distribution of transmitted light with respect to the same original. As can be seen from the figure, the transmitted light is distributed in an area other than the area corresponding to the reflective original image 10, 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 being scanned, and has a high voltage in the section where only the other transparent sheet 11 is present. .

The output signal of this line sensor 25 is input to a gradation circuit 34 via an A/D conversion circuit 32 and a shading correction circuit 33. As mentioned above, the gradation circuit 34 has the characteristics of the gradation curve B (FIG. 3), that is, the voltage value is intermediate between the signal voltage value in the transmitted light region and the signal voltage value in the non-transmitted light region. It functions as a first binarization circuit that performs binarization processing using the threshold value. Therefore, the output signal of the gradation circuit (first binarization circuit) 34 becomes a signal of a constant low voltage "L" in the section where the reflective original image 10 is scanned, and only the transparent sheet 11 other than that. In the section where the area where the voltage exists is being scanned, the signal becomes a constant high voltage "H".

The output signal of this gradation circuit 34 is input to a sharpness emphasizing 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 the input image signal is sent to the filter processing circuit within the sharpness enhancement circuit 35. An unsharp signal U is created by averaging the input image signal S and the image signals of a plurality of surrounding pixels. FIG. 4c shows the unsharp signal U created in this way.

This unsharp signal U is input to the second binarization circuit 37 at the next stage. Second binarization circuit 37
Now, the "H" level of the unsharp signal U (that is, the signal voltage value corresponding to the transmitted light region) and the "L" level
The unsharp signal U is binarized using a predetermined voltage value located in the middle of the signal voltage level (that is, the signal voltage value corresponding to the non-transmitted light region) as a threshold value (see FIG. 4c), and the unsharp signal U is binarized as shown in FIG. Create a binary signal as shown in . This binary signal T becomes a constant high voltage "H" signal 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 (predetermined voltage value) of the unsharp signal U In a section corresponding to a voltage section lower than a predetermined voltage value), the signal is a constant low voltage "L". At this time, the voltage value of the low voltage "L" commands 0% shading in the subsequent exposure recording section 43,
The voltage value of the high voltage "H" is selected to command 100% shading. By the way, the predetermined voltage value corresponding to the above-mentioned threshold value (Fig. 4c) can be adjusted by operation from an external operation panel, so by changing this threshold value, the binarization can be performed. The length of the "L" level section of the signal T can be adjusted. That is, if the threshold value (predetermined voltage value) is set to a voltage value halfway between the "H" level and "L" level of the unsharp signal U, the section length of the "L" level of the binarized signal T can be reduced. can be made to match the section length of the non-transparent light area (the area corresponding to the area of the original image 10 in FIG. 4a). If the threshold value (predetermined voltage value) is brought closer to the "L" level of the unsharp signal U from the intermediate voltage value, the length of the "L" level section of the binarized signal T will be changed accordingly. Conversely, the threshold value (predetermined voltage value) can be set to "H" of the unsharp signal U.
As the level approaches the "L" level, the section length of the "L" level of the binarized signal T can be increased accordingly. Fourth
In the example shown, the threshold value is set lower than the intermediate voltage value of the unsharp signal U, so the binarized signal T
The section length of the “L” level is the non-transmitting light region (fourth
This area is shorter than the section length of the area (corresponding to the area of the original image 10 in Figure a).

This binary signal T is sent to the next stage magnification adjustment circuit 36.
After the data is inputted to and subjected to data processing for magnification adjustment, it is inputted to the halftone dot generation circuit 38 of the exposure recording section 43. In the exposure recording section 43, the laser beam projected from the laser device 40 is controlled on/off by the light modulator 39 based on the above-mentioned binarized image data, and is scanned onto the unexposed film 41. . As a result, the "L" level section of the binarized signal T is shaded at 0%, and the binarized signal T
In the "H" level section, a 100% shaded duplicate image is 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 a developing section 44, where it is developed and a mask plate 7 shown in FIG. 9 is created. Figure 4e shows mask version 7.
The area 14 corresponding to the "L" level of the binarized signal T is shaded to 0% and becomes a transparent area called "blank", and the area 14 corresponding to the "L" level of the binarized signal T is shaded to 0% and becomes a transparent area called "blank". The region 15 corresponding to the "H" level of T is shaded to 100% and is an opaque region called "solid". In the example shown in FIG. 4, since the "L" level section length of the binary signal T is shorter than the section length of the reflective original image 10, the transparent area 14 of the mask plate 7 is shorter than the reflective original image 10 by that much. The dimensions are also smaller.

The thus created mask plate 7 (Fig. 9) is positioned and superimposed on the already created halftone plate 6 (Fig. 8), and this is set in a contact printer and exposed while being in close contact with the unexposed film. , the picture plate 5 shown in FIG. 7 is created.

Effects of the Embodiment As described above, in this embodiment, the shading of the halftone plate 6 shown in FIG. It can be of high quality. In addition, since the mask plate 7 is created by electronically hatching using a mask plate creating device in the same manner as the halftone plate 6, the magnification and distortion rate of the reproduced image are different from those of the mask plate 7 and the halftone plate 6. It becomes equal with
A highly accurate pattern version 5 can be created. Moreover, when creating the mask version 7, the second
By adjusting the threshold value (predetermined voltage value) of the value conversion circuit 37, the size of the transparent area 14 of the mask plate 7 can also be adjusted. 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 plate 5 using a contact printer, when overlapping the mask plate 7 and the halftone plate 6, the transparent area 14 and the pattern area 16 can be easily registered, and the plate making process can be easily performed. Work efficiency can be improved. Also, the second 2
By setting the threshold value (predetermined voltage value) of the value conversion circuit 37 higher than the intermediate voltage value of the unsharp signal U, it is possible to create a mask plate 7 having a transparent area 14 having a size slightly larger than that of the reflection original image 10. In this case, using the mask version 7 and the shaded version 6,
It is possible to create a pattern plate 5 in which a border (for example, a mesh of about 20%; this can be changed arbitrarily) is created around the periphery of the pattern area.

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 embodiments, a black and white apparatus in which the original image is black and white has been described, but the present invention can also be applied to a case 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 production method and the production device of the present invention, it is possible to create a mask plate that can accurately mask a halftone plate created by electronically hatching. 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 configuration diagram showing the input section of a mask plate making device which is an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing the signal processing section and output section of the same device, and FIG.
The figure is a characteristic diagram showing the relationship between input voltage and output voltage of the 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 printing plate. 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, and Fig. 10 is a plan view of the plate used for plate making. FIG. 2 is a schematic configuration diagram of a camera. 6...Shading plate, 7...Mask plate, 10...Reflection original image, 11...Transparent sheet, 22...Light source, 24...Image scanning section, 34...Gradation circuit (first binarization circuit), 35...Sharpness Emphasis circuit (unsharp signal creation circuit), 37...Second binarization circuit, 43
...Exposure recording section, 44...Development section.

Claims (1)

[Scope of Claims] 1. By scanning the reflection original image pasted on a transparent sheet from the front side of the original image, exposing and recording the shaded duplicate image on an unexposed film, and developing this exposed film. A method for creating a mask plate for masking the obtained halftone plate, wherein transmitted illumination is applied from the back side of the transparent sheet to which the reflective original image is pasted, and the image is scanned from the front side of the original image. The image signal is binarized using a voltage value between the signal voltage value in the transmitted light region and the signal voltage value in the non-transmitted light region as a threshold value, and the binarized image signal is processed by a filter to obtain the result. An unsharp signal is created by adding and averaging the image signal and the image signals of multiple pixels around it, and the unsharp signal is set between the signal voltage value corresponding to the transmitted light area and the signal voltage value corresponding to the non-transmitted light area. Mask plate creation involves performing binarization processing using a predetermined voltage value as a threshold value, and using the binarized image signal to expose and record a duplicate image on an unexposed film and developing it to create a mask plate. Method. 2 Scanning the reflection original image pasted on a transparent sheet from the front side of the original image, exposing and recording the shaded duplicate image on unexposed film, and developing the exposed film to obtain a halftone plate. An apparatus for creating a mask plate for masking, 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; a light source disposed above the original image setting section; An image scanning unit disposed below the original image setting unit converts the image signal obtained by scanning the image by the image scanning unit to a voltage between the signal voltage value of the transmitted light area and the signal voltage value of the non-transmitted light area. 2 with the value as the threshold
a first binarization circuit that performs digitization processing; and a filter process the image signal that has been binarized by the first binarization circuit, and add the image signal and a plurality of surrounding image signals. an unsharp signal creation circuit that creates an averaged unsharp signal; a second binarization circuit that performs binarization processing as a second binarization circuit; and an exposure recording section that records a duplicate image on an unexposed film by exposure using the image signal binarized by the second binarization circuit. Also, a mask plate making 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.