JPH0750299B2 - Plate making camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plate-making camera, and more particularly to a plate-making camera that exposes a display image of a CRT on a photosensitive material to form a printing plate.

[Conventional technology]

In the production of a block original for printing, a plate making camera is used which exposes the original image using an exposing means (lens shutter etc.) through a contact screen which is brought into close contact with the photosensitive material. The exposed light-sensitive material is processed by a processing means such as an automatic developing machine to produce a master copy document. In addition, various plate-making cameras in which an exposing means for making a block for printing and a processing means are integrated have been proposed.

A plate-making camera in which these exposing means and processing means are integrated supplies a photosensitive material, forms an image of an original for a master plate on the photosensitive material, exposes the photosensitive material, and processes the exposed photosensitive material. I have. Then, as a processing method of the photosensitive material, there are a diffusion transfer method, a lith development method, and a PQ development method.

The conventional plate-making camera in which the exposure means and the processing means are integrated will be briefly described with reference to FIG. 9 by taking a plate-making camera using diffusion transfer as an example.

FIG. 9 is a schematic block diagram showing the structure of a plate-making camera using diffusion transfer disclosed in JP-A-56-70542.

First, the diffusion transfer photosensitive material 14 is carried out from the photosensitive material storage section 10 by the first conveying means 12 having an endless belt, and reaches the predetermined position of the photosensitive material adsorbing means 16 (a position where the image of the original can be accurately exposed). Transport.

Next, at this predetermined position, the photosensitive material 14 has its base surface side adsorbed and fixed by the photosensitive material adsorbing means 16, and
After the contact screen 18 is brought into close contact with the emulsion surface side, the image of the original 22 attached to the original attaching portion 20 is imaged and exposed on the photosensitive material by the exposure means 24 such as a lens shutter. During this exposure, the light source (not shown) irradiates the original 22 with uniform light.

Next, when the exposed photosensitive material 14 is conveyed to the image receiving material storage portion 30 by the second conveying means 26 composed of a pair of rollers via the guiding device 28, the exposed surface of the photosensitive material 14 receives the image of the image receiving material 32. Abut the surface.

Next, the photosensitive material 14 and the image receiving material 32, whose photosensitive surface and image receiving surface are in contact with each other, are conveyed into the processing liquid tank 36 by the third conveying means 34 including a pair of rollers, and then are conveyed to the pair of rollers 38. To do. Then, when the superposed photosensitive material 14 and image receiving material 32 pass through the contact portion of the roller 38, the photosensitive material 14
The halftone image of is diffuse-transferred to the image receiving material 32.

Next, the light-sensitive material 14 and the image-receiving material 32 thus superposed are conveyed to the take-out port 40. Then, the photosensitive material 14 and the image receiving material
By peeling off to 32 and 32, a desired master plate made of the image receiving material 32 can be obtained.

[Problems to be solved by the invention]

However, in the conventional plate-making camera, a manuscript for the plate-making camera is created, and the created manuscript is attached to the manuscript mounting portion to form an image on the photosensitive material by the exposure means and exposed to create a desired printing master plate. Since it is necessary to create a document once when creating a block copy from an image such as a video source, it is troublesome and costly. There was a problem.

In addition, when the image displayed on the CRT is captured, the scanning line is captured, which makes it difficult to view the captured image. For this reason, the scanning lines are moved in the vertical direction to increase the scanning lines and blur the scanning lines (hereinafter referred to as "lastylase").

When a CRT image that has been rasterized in this way is taken with a camera equipped with a mechanical shutter, the shutter may be opened and closed before scanning one frame of the CRT image, so the image taken on the film There is a problem in that uneven exposure occurs on the substrate and the exposure time becomes long in order to prevent this uneven exposure.

That is, when the number of scans in a region where the number of scans is large is N and the number of scans in a region where the number of scans is small is N−1 when scanning is performed halfway on the CRT screen, the density difference ΔD
Is represented as follows.

However, γ is a γ value of a film on which a CRT image is taken, and is usually about 3.

Here, since the density difference that can be recognized by the human eye is about 0.01, N = 129 from the above equation (1). On the other hand, since the exposure time is usually about 2 sec, N is less than 129 when the CRT screen is photographed with this exposure time, and uneven exposure occurs. In addition, the time corresponding to N = 129 is about 17 seconds (in the case of performing 8 times the last stylization at the scanning speed of 525/60 Hz), and the exposure time becomes long.

In order to prevent this uneven exposure, it is possible to open and close the camera shutter in synchronization with the CRT image frame.However, using a mechanical shutter as in the past, the shutter is opened and closed when the shutter is opened. Since the CRT image is partially shielded by the film, uneven exposure cannot be completely prevented.

A first object of the present invention is to solve the above problems, and to provide a plate making camera capable of directly producing a printing block from a video source or the like without producing an original for the plate making camera. It is to be.

Another object of the present invention is to make a plate for printing directly from a video source or the like without making an original for a plate making camera, and to make a plate with high image quality without uneven exposure. It is to provide a camera.

[Means for solving problems]

To achieve the above object, the present invention provides a CRT that displays an image of a master copy document according to an image signal output from an image input unit that outputs an image signal corresponding to the master copy document, and the CRT.
Exposure means for forming an image of a master copy original image displayed on the RT on a photosensitive material having a contact screen in close contact with the emulsion surface and exposing the same, and vertical sync separation means for separating the vertical sync signal from the image signal. , A scanning position moving means for moving the scanning position of the CRT image in the vertical direction at regular intervals, a counting means for counting the number of the vertical synchronizing signals, and a photographing magnification of m, 1.
When the scanning time of the unit elements constituting the screen is t, the exposure time at equal magnification is t ₀ and K is an integer, the integer part of the following equation is n, and the number of the vertical synchronizing signals is 2 ^K · n. And an exposure control means for controlling the exposure means so that the exposure time corresponds to 2 ^K · n.

In the present invention, the photographing magnification is 0.8 to 4, and the K
The value of was set to any one of 1, 2 and 3.

Further, according to the present invention, the scanning position moving means delays the vertical synchronizing signal or changes the voltage of a sawtooth wave for vertical scanning to move the scanning position of the CRT image at a constant interval in the vertical direction.

In the present invention, the vertical synchronizing signal is a vertical blanking signal for blanking.

Further, the present invention is configured by integrating the exposure means with the processing means.

[Action]

According to the present invention, the CRT displays the image of the master copy document according to the image signal output from the image input unit that outputs the image signal corresponding to the master copy document. The exposing means forms an image of the original for master plate displayed on the CRT on a photosensitive material having a contact screen closely attached to the emulsion side, and exposes the image.

In this way, the image displayed on the CRT is exposed to the photosensitive material by the exposure means in accordance with the image signal corresponding to the image of the original document for the master copy output from the image input section, and the exposed photosensitive material is processed. Since the printing block is created, it is not necessary to create a document for the plate-making camera, create the document, and set the created document on the document mounting portion, so that the block can be created easily and quickly.

Further, the vertical sync signal is separated from the video signal by the vertical sync separating means. The vertical sync signal is a vertical sync pulse for moving the scan line from the bottom of the CRT screen to the top of the CRT screen. A signal (blanking signal) can be used. The scanning position moving means is CR
Last scan is performed by moving the scanning position of the T image in the vertical direction at regular intervals. As a method of performing the last styling, there are a method of delaying a vertical synchronizing pulse and a method of changing the voltage of a sawtooth wave for vertical scanning. When delaying the vertical synchronizing pulse, the time for delaying the vertical synchronizing pulse is sequentially increased or randomly increased. Further, when changing the voltage of the sawtooth wave for vertical scanning, the value for changing the voltage is sequentially increased or randomly increased. By performing the rasterize in this manner, the scanning position of the CRT screen is moved in the vertical direction by a constant distance, the raster is moved in the vertical direction, and the scanning line after photographing is not visible. The counting means counts the number of vertical synchronizing signals when the rasterize is performed as described above. And
Exposure control means controls the exposure means so that the exposure time when the number of the vertical synchronizing signal and the 2 ^K · n corresponds to 2 ^K · n. However, K is an integer. n as t ₀ the exposure time when the scan time t and the equivalent magnification of unit elements that constitute the photographing magnification m, 1 screen (for example one field), Is the integer part of the expression. It is preferable to use a value of 0.8 to 4 for this photographing magnification.

Here, the scanning method may be interlaced scanning in which the screen is scanned twice and one screen is completely transmitted.
A normal scan (non-interlace) in which one screen is sent by one scan may be used. The optimum value of K is selected according to the number of scanning lines. For example, K = 3 for a CRT with a scanning speed of 525/60 Hz and K = 2 for a CRT with a scanning speed of 1125/60 Hz.
It is said that Therefore, in the case of K = 1, the case of displaying the screen of 1 frame by two fields (in the case of interlace) and the case of moving the scanning line in the vertical direction and scanning the image of 1 frame twice (For non-interlaced) When K = 2, there are cases where the scanning line is moved to display 4 fields, that is, 2 frames (in the case of non-terrace), and cases where the scanning line is moved to display 4 frames. When K = 3, there are cases where the scanning line is moved to display 8 fields, that is, 4 frames, and cases where the scanning line is moved to display 8 frames.

Furthermore, by adopting a configuration in which the exposure means and the processing means are integrated, there is no need to perform processing by another processing means,
It is possible to further speed up the production of a block copy.

〔Example〕

 Embodiments of the present invention will be described in detail below with reference to the drawings.

The first embodiment described here is one in which the present invention is applied to the plate making camera using the diffusion transfer shown in FIG.
FIG. 1 shows a block diagram of the plate-making camera. The same components as those of the plate-making camera using the diffusion transfer shown in FIG. 9 are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, the image display means 52 is a video image input unit.
80, control circuit 78, D-flip flop 73, deflection circuit 7
4. An OR circuit 76, a deflection coil 66 composed of a vertical deflection coil and a horizontal deflection coil, a cathode 68, and a CRT 72 having a fluorescent surface 70.

The video image input unit 80 includes a deflection circuit 74 via a control circuit 78.
It is connected to the. The video image input unit 80 outputs the image signal of the master copy document stored in the video source such as a video tape, a video disk, and a video floppy. Note that an image signal such as a computer graphic may be output.

The deflection circuit 74 outputs an S terminal that outputs a sawtooth wave current for vertical scanning and a sawtooth wave current for horizontal scanning, and a vertical blanking signal V.BL to prevent the electron beam from being irradiated during the blanking period. And a H terminal for outputting a horizontal blanking signal H.BL for preventing the electron beam from being irradiated during the horizontal blanking period. The S terminal of the deflection circuit 74 is connected to the deflection coil 66 so as to supply a sawtooth current to the vertical deflection coil and the horizontal deflection coil. The H terminal of the deflection circuit 74 is connected to the cathode 68 of the CRT 72 via the OR circuit 76. The V terminal of the deflection circuit 74 is connected via the OR circuit 76.
It is connected to the cathode 68 of the CRT 72, connected to the clock terminal CK of the D-flip flop 73, and further connected to the control circuit 78. The Q terminal of the D-flip flop 73 is connected to the cathode 68 of the CRT 72 via the OR circuit 76.

An exposure start switch 75 and a format switch 79 which are turned on at the start of exposure are connected to the control circuit 78. The output port of the control circuit 78 is connected to the shutter mechanism 25 of the camera via the shutter actuating solenoid 77, and is also connected to the D terminal of the D-flip flop 73 so as to supply the video signal, and to the lamp 41. It is connected.

Further, it is preferable that the image display means 52 is provided with the functions of scanning line erasing (lastylase) and automatic scanning line pull-in corresponding to input video signals of various scanning lines. Also,
The number of scanning lines of the image displayed on the CRT is preferably as large as possible in order to improve the image quality of the block image to be produced, and particularly preferably about 1000 to 2000 or more.

Next, the rasterization of the image displayed on the CRT 70 will be described with reference to FIGS. 2 and 3.

As shown in FIG.
The vertical sync signal is separated by. The vertical sync signal is a vertical sync pulse for moving the scan line from the bottom of the CRT screen to the top of the CRT screen, or a blank line that erases the retrace line when the scan line moves from the bottom of the CRT screen to the top. An erase signal (blanking signal) can be used. The scanning position moving means moves the scanning position of the CRT image in the vertical direction at regular intervals to perform the rasterize. As a method of performing the last styling, there are a method of delaying a vertical synchronizing pulse and a method of changing the voltage of a sawtooth wave for vertical scanning. When delaying the vertical synchronizing pulse, the time for delaying the vertical synchronizing pulse is sequentially increased or randomly increased. Further, when changing the voltage of the sawtooth wave for vertical scanning, the value for changing the voltage is sequentially increased or randomly increased. By performing the rasterize in this way, the scanning position of the CRT screen is moved in the vertical direction by a constant distance, the raster is moved in the vertical direction, and the scanning line becomes invisible when the image is taken. The counting means counts the number of vertical synchronizing signals when the rasterize is performed as described above. Then, the control means controls the exposure time so that the exposure time is equal to the number of vertical synchronizing signals 2 ^K · n. However, K and n are integers.

Here, the scanning method is interlaced scanning in which the screen is scanned twice and one screen is completely transmitted (hereinafter referred to as interlace).
However, normal scanning (hereinafter referred to as non-interlace) in which one screen is sent by one scanning may be used. The optimum value of K is selected according to the number of scanning lines. For example, 525 / 60Hz
In a CRT having a scanning speed of 1), K = 3, and in a CRT having a scanning speed of 1125/60 Hz, K = 2. Therefore, in the case of K = 1, a case where a screen of one frame is displayed by two fields (in the case of interlace) and a case where the scanning line is moved in the vertical direction and the image of one frame is scanned twice ( In the case of non-interlace). In the case of K = 2, the scanning line may be moved to display four fields, that is, two frames (in the case of interlace), and the scanning line may be moved to display four frames. When K = 3, there are cases where the scanning line is moved to display 8 fields, that is, 4 frames, and cases where the scanning line is moved to display 8 frames. In the following, the scanning speed of 524 / 60Hz with non-interlacing with K = 3
A description will be given of the CRT's lastize, but the same lastize can be performed by setting K to an optimum value for a CRT having a scanning speed of 940/60 Hz and a scanning speed of 1125/60 Hz. Also, in case of interlace, 2
The rasterization can be performed by moving the scanning line for each field, that is, for each frame. Second
The figure shows the relationship between the vertical blanking signal V.BL and the sawtooth wave for vertical scanning. When the offset voltage V _OF is applied to the sawtooth wave for vertical scanning, the uppermost scanning start position on the CRT screen moves vertically, which allows the scanning position to move vertically. Therefore, the offset voltage V _OF is 0, 1V, 2V, 3V ... 7
It is possible to move the scanning line in the vertical direction by a predetermined amount by sequentially increasing V and a predetermined amount V for each repetition.
FIG. 4 (1) shows a scanning line moving state in non-interlace when the offset voltage V _OF is sequentially increased by a predetermined amount and the scanning line is multiplied by 8 as described above. The numbers on the left side of the figure indicate the scanning order. Also, the offset voltage V _OF
The scanning line can be randomly moved in the vertical direction by randomly increasing V by 0, 4V, 2V, 6V, 1V, 5V, 3V, 7V by a predetermined amount and repeating this. FIG. 4 (2) shows the scanning state when the scanning line in the non-interlace is multiplied by 8 when the offset voltage V _OF is randomly increased in this way. The numbers on the left side of the figure indicate the scanning order. Further, as shown in FIG. 3, the vertical sync pulse separation circuit 200 separates the vertical sync pulse from the video signal, and the delay circuit 202 delays the vertical sync pulse by the time set by the counter 204, and the delay circuit 202 delays the vertical sync pulse via the deflection circuit 74. By supplying the vertical deflection coil of the deflection coil 66
The uppermost scanning start point on the CRT screen can be moved in the horizontal direction, thereby moving the scan line in the substantially vertical direction. Here, a count value that is sequentially increased by a predetermined amount from the counter 40, for example, 0 μsec, 8 μse
Periodically, c, 16 μsec, 24 μsec, ... 56 μsec are supplied to the delay circuit 38, and the vertical synchronizing pulse is sequentially delayed by the predetermined amount by the delay circuit 38, so that the scanning line becomes vertical as in FIG. 4 (1). It can be moved by a predetermined amount in the direction. The above 8 μsec is obtained by dividing the horizontal scanning time by the number of scanning lines (8 in the above case). Also, a count value that randomly changes from the counter 40, for example, 0 μsec, 32 μsec, 16 μsec, 48
By similarly supplying signals of μsec, 8μsec, 40μsec, 24μsec, 56μsec to the delay circuit 38 and delaying the vertical synchronizing pulse, the scanning lines are randomly oriented in the vertical direction as shown in Fig. 4 (2). Can be moved to.

The operation of the present embodiment in the case where the rasterization is performed as described above, the image from the video source is displayed on the CRT, and this image is photographed through the exposure system such as the lens and the shutter, will be described. FIG. 5 shows the main routine executed when the exposure start switch 75 is scanned and turned from off to on. When the exposure start switch 75 is turned from off to on, the lamp 41 is turned on in step 100. To indicate that shooting has started.

At the next step 102, it is judged whether or not a predetermined time (for example, 50 msec) has elapsed, and if it has elapsed, at step 104, the shutter operating solenoid 77 is excited to operate the shutter mechanism. It should be noted that if the CRT is lit within the above predetermined time, it is turned off. This shutter mechanism normally opens completely within an operating time of about 50 to 100 msec. In the next step 106, the operation shown in the following equation is performed to set the integer part to the value of n. However, keep the brightness and contrast of the CRT constant.

However, m is a photographing magnification represented by the size of the film image / the size of the monitor image, and usually takes a value of 0.8 to 4 and is determined by the state of the format switch 79. Further, t ₀ is a normal exposure time of m = 1, and t is a time per field. Here, when scanning is performed by interlaced scanning at a scanning speed of 525/60 Hz, t = 1/60.

At the next step 108, it is judged whether or not a predetermined time (for example, 500 msec) has elapsed in consideration of a margin time until the shutter is completely opened, and if it has elapsed, a vertical blanking signal V. Judge whether BL is input or not. When it is determined that the vertical blanking signal V.BL has been input, the display signal is raised in step 112. In this case, FIG. 7 (5) to (7)
Display signal (see Fig. 7 (5))
The first vertical blanking signal V.BL after
The vertical blanking signal V.BL (see FIG. 7 (7)) supplied to the cathode of the CRT 16 by (see FIG. 7 (6)) falls, so that the screen is displayed on the CRT 16 and the film is displayed. Exposure is started. That is, the start of film exposure is synchronized with the vertical blanking signal V.BL. Next, in step 114, it is determined whether or not 8n = C. This C is a count value counted by an interrupt routine interrupted at each rising edge of the vertical blanking signal V.BL in FIG.
In step 2, it is judged whether or not the display signal is at the high level. When the display signal is at the high level, the count value C is incremented at step 124. When the display signal is at the low level, the count value C is reset at step 126 and the process returns to the main routine. As a result, the count value C counts the number of rising times of the vertical blanking signal V.BL when the display signal is at a high level, that is, the number of vertical blanking signals V.BL. Value of 8 times n calculated in step 106 in step 114 (8n)
Is determined to be equal to the count value C counted in step 124, the display signal is lowered in step 116, and it is determined in step 118 whether two vertical blanking signals V.BL have passed. , When the time has elapsed, the solenoid 30 for operating the shirt is demagnetized in step 120.

FIG. 7 shows the waveform of each part when controlled as described above. As shown in the figure, when the vertical blanking signal V.BL rises with the shutter open, a display signal is output and input to the D terminal of the D-flip flop 73 (FIG. 1).

Since the vertical blanking signal V.BL is input from the deflection circuit 74 to the clock terminal CK of the D-flip flop 73, the signal shown in FIG. 7 (7) is output from the Q terminal of the D-flip flop 73. The signal is supplied to the cathode 68 via the OR circuit 76. Therefore, when the vertical blanking signal V.BL shown in Fig. 7 (7) is at low level, CR
An image is displayed at T72, and when the vertical blanking signal V.BL shown in FIG. 7 (7) becomes high level, the image display on the CRT 72 is stopped. Then, when the vertical blanking signal V.BL rises 8n times, the supply of the display signal is stopped, which causes the next rising of the vertical blanking signal V.BL as shown in FIG. 7 (7). Then, the vertical blanking signal V.BL supplied to the cathode 68 rises, the display of the CRT image is stopped, and the exposure on the film is completed. That is, the end of exposure of the film is synchronized with the vertical blanking signal V.BL.

As described above, in the CRT image capturing apparatus according to the present invention, the exposure start and the exposure end of the film are synchronized with the vertical blanking signal V.BL, that is, the vertical synchronizing signal, and the exposure time depends on the presence or absence of the rasterize. Regardless of this, since the time is automatically controlled to correspond to an integral multiple 2 ^K · n of the number 2 ^K of vertical synchronizing signals forming one screen, uneven exposure on the film does not occur.

That is, the shutter operation is performed (see FIG. 7 (4)) and a display signal is generated after a predetermined period has elapsed (see FIG. 7 (5)). The number of vertical synchronization signals constituting one screen is 2
^The exposure is started from the time when an arbitrary vertical synchronizing signal in ^K (8 in the above embodiment) is generated. Then, the exposure is finished at the time when the arbitrary vertical synchronizing signal relating to the end of the n-screen exposure is generated (see (6) and (7) in FIG. 7). As a result, in the number 2 ^K of the vertical synchronizing signal constituting one screen, the effect is obtained that the circuit configuration becomes easier to control since the may start the exposure by any of the synchronization signals is simplified.

Although the case of K = 3 has been described above, the optimum value of K is selected according to the number of scanning lines of the CRT. Further, in the above, since the CRT is illuminated with the shutter open, this shirt mechanism can be omitted. Furthermore, although the example in which the exposure time is controlled by the blanking signal has been described above, the exposure time is controlled by controlling the electronic shutter while the CRT is illuminated using a camera equipped with a high-speed electronic shutter. Good.

FIG. 8 is a schematic block diagram showing another example of the image display means shown in FIG. The same components as those described above are designated by the same reference numerals and description thereof will be omitted.

As shown in the figure, the image display means 52 includes an image input unit 138.
A video image input unit 80, a computer graphic (CG) image input unit 140, a character image input unit 142, and a TV camera image input unit 144 are provided as the components. Each image input unit is connected to the image processing unit 146.

A frame memory 148 is connected to the image processing 146, and a CRT 72 is connected via a CRT drive circuit 150.

The image processing unit 146 synthesizes the image signals from the respective image input units and sequentially outputs the image signals from the image input units to the frame memory 148.

The frame memory 148 sequentially stores image signals from the image input unit.

The CRT drive circuit 150 outputs the image signal, which has been subjected to the image combining processing by the image processing unit 146, to the CRT 72 and displays the image corresponding to the image signal on the screen of the CRT 72.

With the above configuration, the respective image signals from the image input unit 138 are combined, and the combined image is displayed on the screen of the CRT 72. Then, the exposure means 24 shown in FIG. 1 forms an image on the photosensitive material and exposes it. Therefore, it is possible to create a block copy of a combined image in which the image signals output from the respective image input units are combined.

Further, in the embodiment shown in FIG. 1, an example is shown in which a master plate is prepared using a diffusion transfer type photosensitive material, but other types of photosensitive materials such as a lith developing photosensitive material and a PQ developing photosensitive material may be used. You may

In the embodiment shown in FIG. 1, the exposure means and the processing means are integrated, but the exposure means and the processing means are separated and the once exposed photosensitive material is developed by the processing means provided separately. You may do it.

As described above, the image for the artwork is displayed on the screen of the CRT according to the image signal corresponding to the image for the artwork output from the image input unit, and the displayed image of the CRT is used as the photosensitive material. Since an image can be formed and exposed, it is not necessary to prepare a document for a plate-making camera, and the process can be simplified.

〔The invention's effect〕

As described above, according to the present invention, the scanning position of the CRT image is moved in the vertical direction, and the exposure time considering the change in the exposure amount according to the shooting magnification is determined in synchronization with the vertical synchronization signal. The exposure time will be determined by an integer multiple of the number of rasters according to the above, and it is possible to prevent exposure unevenness as well as to perform exposure with an appropriate exposure amount regardless of the exposure magnification. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a plate making camera of a first embodiment according to the invention, FIG. 2 is a diagram showing a relationship between a blanking signal and a sawtooth wave for vertical scanning, and FIG. 3 shows a vertical synchronizing pulse. Block diagram of the circuit that delays and performs the last style.
FIGS. 4 (1) and 4 (2) are diagrams showing the change state of the scanning line when 8 times the last style is performed, FIG. 5 is a flowchart showing the main routine of the control circuit, and FIG. 6 is the control circuit. 7 is a flow chart showing an interrupt control routine of FIG. 7, FIG. 7 is a diagram showing waveforms of respective parts, FIG. 8 is a schematic configuration diagram showing another image display means, and FIG. 9 is a schematic configuration diagram showing a conventional plate-making camera. . 52 ... Image display means, 14 ... Photosensitive material, 72 ... CRT, 24
…… Exposure means. 80 …… Video image input section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-139733 (JP, A) JP-A-58-43446 (JP, A) JP-A 61-4036 (JP, A) JP-A 51- 36933 (JP, A) JP 57-89380 (JP, A) JP 57-86722 (JP, A) JP 49-60921 (JP, A) JP 61-36730 (JP, A)

Claims (6)

[Claims] 1. A CRT for displaying an image of a master copy document according to an image signal output from an image input section for outputting an image signal corresponding to the master copy document, and a master copy displayed on the CRT. An exposure means for forming an image of a document on a light-sensitive material having a contact screen closely attached to the emulsion side and exposing it, a vertical synchronization separation means for separating a vertical synchronization signal from the image signal, and a vertical scanning position for the CRT image. Scanning position moving means for moving the unit at a constant interval in the direction, counting means for counting the number of the vertical synchronizing signals, photographing magnification m, scanning time of unit elements constituting one screen is t, exposure time at equal magnification Where t ₀ and K are integers and the integer part of the following equation is n, and the number of vertical synchronization signals is
Process cameras equipped with an exposure control means for exposure time with respect to the 2 ^K · n controls the exposing unit so as to correspond to 2 ^K · n. 2. The plate-making camera according to claim 1, wherein the photographing magnification is 0.8 to 4. 3. The plate-making camera according to claim (1) or (2), wherein the value of K is one of 1, 2 and 3. 4. The scanning position moving means delays the vertical synchronizing signal or changes the voltage of a sawtooth wave for vertical scanning to move the scanning position of a CRT image in the vertical direction by a predetermined distance. The plate-making camera according to any one of items 1) to 3). 5. The plate-making camera according to claim 1, wherein the vertical synchronizing signal is a vertical blanking signal for blanking. 6. The plate-making camera according to claim 1, wherein the exposing means is integrated with a processing means.