JPH0452142A - Video printer - Google Patents

Abstract

PURPOSE:To obtain a multi-gradation hard copy without using a complex processing circuit by using a liquid crystal panel of binary gradation by a method wherein an image signal data is binary coded with a specific threshold, a plurality of binary data are obtained by varying the threshold, and exposure is performed a plurality of times following them to form a multi-gradation image. CONSTITUTION:An image data for obtaining a hard copy is binary coded by a specific threshold with a binary circuit 82. Said binary coded data is displayed on a liquid crystal panel 18 of binary gradation to expose a recording medium. The threshold in the binary circuit 82 is varied to repeat the display on the liquid crystal panel 18 and the exposure. A multi-gradation image hard copy is obtained thereby, and a multi-gradation high quality image can be formed with the binary gradation liquid crystal panel with using a multi-gradation liquid crystal panel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video printer, and more particularly to a video printer that forms a hard copy of a visible image from a video signal.

BACKGROUND ART Conventionally, visible image recording devices known as video printers include the following.

For example, the applicant's pending patent application, JP-A-62-
No. 16695 describes an image recording device that receives a video signal of an image taken with an electronic still camera, reproduces it on a CRT, and records this CR7 image on color photographic paper. There is also an apparatus that uses a method of exposing an instant photosensitive material with an image displayed on a CRT, and uses an imaging optical system using an optical fiber or a lens. Furthermore, for example, Japanese Patent Publication No. 64-10991 (Japanese Patent Publication No. 58-212287)
A thermal printer has also been proposed in which a heat-diffusible dye is transferred to an image-receiving medium to obtain an image profile, as described in .

However, none of these devices is simple and is not small enough to be portable, for example, in a pocket.

The present applicant has proposed, for example, in Japanese Patent Application No. 1-237094, a small-sized video printer that can solve these problems and easily obtain a hard copy of a visible image from a video signal. This printer is driven by a video signal, and a liquid crystal panel on which a black and white image is displayed is brought into close contact with a photosensitive recording medium. Light from a light source is guided through a filter to the liquid crystal panel to expose the displayed image onto the photosensitive recording medium, and then, It is developed to obtain a hard copy print. According to such a printer, hard copies can be easily obtained and the device can also be made smaller.

By the way, when displaying an image according to a video signal on a liquid crystal panel as described above and exposing this image to a photosensitive recording medium, it is necessary to make the image quality of the resulting hard copy a continuous tone high quality one. requires a multi-gradation, multi-pixel liquid crystal panel. However, multi-gradation LCD panels are expensive,
Because they are difficult to obtain, there has been a problem in that it is difficult to obtain hard copies of multi-pixel images with multi-IM and II.

A method to solve such problems and obtain hard copies of multi-gradation images using a binary gradation liquid crystal panel is presented by Ohba et al.Full Golor Printingw
ith Two Dimensional B11ev
el Liquid-crystal Modulato
r J (JAPAN DISPLAY '89)
has been proposed. According to this method, one image value data is decomposed into six levels of data according to the signal level, and an image corresponding to each level of data is displayed on the liquid crystal panel, and the data is displayed at different exposure times. Each photosensitive recording medium is exposed to light. A multi-tone image is obtained by superimposing exposures for each of six levels of data in this manner.

However, such a method has the disadvantage that a complicated circuit is required to process the image data, making the apparatus complicated and expensive.

SUMMARY OF THE INVENTION The present invention solves these problems and provides a video printer that uses a binary gradation liquid crystal panel and can produce multi-gradation hard copies without using complicated processing circuits. With the goal.

DISCLOSURE OF THE INVENTION According to the present invention, a video signal representing an image is received and the image is displayed as a black and white image on a liquid crystal panel according to the video signal,
A video printer that records a displayed image as a visible image on a photosensitive recording medium has an input terminal for inputting a video signal,
A binarizing means for binarizing a multi-gradation video signal input from an input terminal using a predetermined threshold value, a threshold variable means for setting the threshold value used in the binarizing means to various values, and a photosensitive recording medium. a two-gradation liquid crystal panel disposed corresponding to the photosensitive surface of the photosensitive recording medium;
A light source that generates sensitizing light in a wavelength range to which a photosensitive recording medium can be sensitized; an optical system that guides the sensitizing light from the light source to a liquid crystal panel; and control means for displaying an image on the screen and controlling the light source, and the control means, upon receiving the video signal at the input terminal, controls the threshold value variable means to set the threshold value used in the binarization means. the binarized image data is outputted to the binarized means for each threshold value, the binarized image data is sequentially displayed on the liquid crystal panel, and the light source is caused to emit light. The operation of exposing the image displayed on the liquid crystal panel to the photosensitive surface of the photosensitive recording medium is performed in accordance with the number of binarized image data, and the so-called multi-width image represented by the video signal is transferred to the photosensitive recording medium. It is something that is exposed to light.

DESCRIPTION OF EMBODIMENTS Next, embodiments of a video printer according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1, 2, and 3, there is shown an embodiment in which a video printer according to the present invention is applied to a printer housed in a compact housing.

This printer receives a color video signal at an input terminal 46, displays the image represented by the image on a liquid crystal panel 18 for each of the three primary color component signals RGB, and uses a color filter 54 to display the image in RGB.
This is a color image recording device that records a hard copy on a recording medium 78 by making the component light of the image incident on the liquid crystal panel 18.

The feature of this printer is that image data to obtain a hard copy is binarized in a binarization circuit 82 using a predetermined threshold value, and the binarized data is displayed on a binary gradation liquid crystal panel 18. By exposing the recording medium 78 to light, changing the threshold value in the binarization circuit 82, and repeating the display and exposure on the liquid crystal panel 18, a hard copy of a four-tone image is obtained.6 The liquid crystal panel 18 is As shown in FIG. 9, a large number of liquid crystal display elements are two-dimensionally arranged in a rectangular matrix array, and when driven by a drive input 36 according to a video signal, an image is visualized as a binary gradation black and white image. It is a visualization device. This drive input 36 is supplied from a drive circuit 44 as described below. As is well known, when the liquid crystal panel 18 is driven according to a video signal, it changes the light transmittance according to the density of the pixel represented by the video signal.In this embodiment, the liquid crystal panel 18 is a binary gradation liquid crystal panel. 18, and binary data is input, so the light transmittance changes depending on the high level or low level of the pixel data represented by the video signal. therefore,
The light 34 that has entered one main surface of the liquid crystal panel 18 is luminance-modulated according to the input binary pixel data, and is emitted from the other main surface 42 .

In this embodiment, the drive circuit 44 and the liquid crystal panel 18 are
It uses a so-called active matrix drive system.

A scanning timing signal for this purpose is supplied from the control circuit 50 via the cap 14.

In order to record a multi-gradation image on the recording medium 78 using such a binary gradation liquid crystal panel 18, this apparatus is provided with a binarization circuit 82 and a threshold variable circuit 6o.

As shown in FIGS. 5A and 5B, the binarization circuit 82 binarizes the video signal data input from the input terminal 4B using a predetermined threshold value Vt. That is, for a portion where the level of the input video signal exceeds the threshold value Vt, an output at a constant level Vt is output, and when the level of the input video signal is below the threshold value Vt, there is no output.

The threshold value Vt used for z-value conversion in the binarization circuit 82 is changed to various values set in advance by the threshold value variable circuit 60. For example, when the input video signal changes in 64 levels as shown in FIG.
Four levels of threshold values are set, and these threshold values are applied to the threshold variable circuit 6.
The signals are sequentially output from 0 to the binarization circuit 82. Binarization circuit 8
2 sequentially creates binarized data using these thresholds,
The signal is output to the liquid crystal panel 18 via the drive circuit 44. The liquid crystal panel 18 displays an image based on binarized data obtained using each of the levels 1 to 64 as threshold values. A hard copy of a multi-tone image is obtained by multiple exposure of these displays onto the recording medium 78.

That is, first, the data that is binarized by the threshold value of level 1 in FIG. exposure is performed. Next, display and exposure are performed in the same way using data that has been binarized using the level 2 threshold, that is, data that is output only for the portion of the input video signal that exceeds level 2. As a result, the portion of the input video signal exceeding level 2 is exposed twice.

Similarly, the data binarized at the threshold 1 of levels 3 to 64 are displayed on the liquid crystal panel 18 and exposed to the recording medium 78, respectively. For example, a portion of the input video signal exceeding level 64 is exposed 64 times to form a density of level 64.

In this way, a multi-gradation image is exposed onto the recording medium 78 using the binary gradation liquid crystal panel 18.

As shown in FIG. 87 and FIG. 8, the liquid crystal panel 18 has a light blocking area 102 on the main surface of the glass support substrate, in which a driving element and electrode wiring for driving the liquid crystal shutter 100 are provided. There is. 7 and 8 show schematic cross-sectional views of the liquid crystal panel 18. FIG. Figure 7 shows LCD shutter 1
00 is shown, and FIG. 8 shows the transparent state of the liquid crystal shutter 100.

The light blocking area 102 always blocks light from the light source 12.

Therefore, only the transmitting region 104 without drive elements etc. is exposed to the light 3.
4 can be transmitted. When the liquid crystal shutter 100 is set to the blocking state by the drive element, the light 34 does not pass through (FIG. 7), but when the liquid crystal shutter 100 is set to the transmitting state, the light 34 passes through the liquid crystal shutter 100 and the transmission area 104. (FIG. 8) 0 In this embodiment, for each liquid crystal shutter 100 area, a transmission area 104 through which light can pass is surrounded by a light blocking area 102, and each vertical and horizontal side of the transmission area 104 is surrounded by a light blocking area 102. The length is set to be one half of the vertical and horizontal length of each liquid crystal shutter 100 area including the surrounding light blocking area 102. Therefore, recording medium 7
The area of the transmissive region 104 that can expose an image to light at 8 is set to one quarter of the area of the entire liquid crystal panel 18 (aperture ratio 2
5%).

The panel moving mechanism 28 moves the position of the liquid crystal panel 18 relative to the recording medium 78 in accordance with a control signal sent from the control circuit 50 as described below. The panel moving mechanism 28 moves the liquid crystal panel 18 in response to a control signal from the control circuit 50.
is a predetermined distance from the recording medium 78.Other mechanical parts of the printer of this embodiment shown in FIGS. 1 to 3 will be explained.

This device basically includes a light source 12, mirrors 14 and 16, and a liquid crystal panel 1 inside a rectangular parallelepiped housing 10.
8, a developing roller 20 and a power source 76 are arranged and configured as shown in the figure. As shown in the figure, the main part of the upper part of the housing IO is open, and two lids 22 and 24 that can be opened and closed are provided on the upper part.

Inside the lids 22 and 24, mirrors 14 and 16 are mounted, and the two channels 22 and 24 are connected by a bellows 26 to optically shield the opening of the housing 10 from light. As a result, the interior space of the housing 10 is formed into a dark box.

The light source 12 is disposed near the left end inside the housing 10 as shown in the figure. The liquid crystal panel 18 is located approximately in the center of the interior space of the housing 10, is supported by the housing 10 by the panel moving mechanism 28, and is moved to change its position relative to the photosensitive sheet 78 as described above. . Lid 22
The housing 10 can be rotated manually by a hinge 30.
As shown in FIG. 2, it opens to a predetermined position slightly larger than 45 degrees to the horizontal, and is held at that position. Similarly, the lid 24 is manually rotatably supported on the housing 10 by a hinge 32, and is opened to a predetermined position slightly smaller than 45 degrees to the horizontal as shown in the figure, and is held at that position. .

The light source 12, the mirrors 14 and 16, and the liquid crystal panel 18 are arranged such that when the lids 22 and 24 are opened and fixed to a predetermined angular position, the light beam 34 emitted from the light source 12 is divided into two mirrors 14 and 18 as shown in the figure. The light is reflected by the liquid crystal panel 18 and is in a positional relationship such that it enters one main surface 40 of the liquid crystal panel 18 at an almost perpendicular angle as nearly parallel light. Lid 2
A switch 70 is provided which responds to the opening of 2 and 24 to a predetermined position. This switch 70 is connected to the control circuit 50 as shown in FIG.
It is possible for the control circuit 50 to detect the opening to a predetermined position of 4.

When the opening/closing lids 22 and 24 are closed, the overall appearance of the casing 10 becomes flat as shown in FIG. 3. This transforms the device into a compact form that can be carried, for example, at least in a pocket.

A film bag 38 that accommodates a plurality of photosensitive recording media 78 such as photosensitive members for instant photography is suitably used as the film bag 38 . As is well known, the photosensitive member of this type of film pack 38 is a photosensitive sheet 7.
8 and a bag containing developer provided at the edge of the sheet, and a plurality of these are stacked and stored in a pack.

After recording the latent image on the photosensitive sheet 78, the developer bag is destroyed and the developer is spread on the photosensitive sheet 78, thereby making the latent image visible. For the purpose of spreading this developer, a pair of developing rollers 20 are provided in this apparatus. An opening (not shown) for loading the film bag 38 is formed on the side surface of the housing 10, and the film bag 38 is loaded into the housing 10 through this opening and is ejected from the housing 10.

The photosensitive recording medium 78 is not limited to such a photosensitive material for instant photography. For example, ordinary color photographic paper or heat-developable silver salt photosensitive materials can be used. The photosensitive material is preferably a heat-developable silver salt photosensitive material. Further, in the case of recording a black and white image, ordinary black and white photographic paper may be used. When such photographic paper is used, a suitable developing mechanism for applying developer to the photographic paper is provided in place of the developing roller 20.

As shown in FIG. 2, the topmost sheet 78 of the photosensitive sheets 78 stacked in the film pack 38
As shown in , the pack 38 is
can be discharged from one side. The developing roller 20 is
A pair of rollers are rotatably supported by the housing 10 in contact with each other, and are driven by a developing roller drive circuit 52 under the control of a control circuit 50 . An opening 80 for discharging the photosensitive sheet 78 is provided on the side surface of the casing 10 as shown.

Note that the developing roller 20 does not need to be driven automatically as described above, but may be driven manually, for example, by manually pulling out the end of the photosensitive recording medium 78 in the direction of the arrow 48.

The liquid crystal panel 18 is supported by the housing 10 so as to be movable in the vertical direction in FIG. 2 by a panel moving mechanism 28. In the operating state, the liquid crystal panel 18 is placed such that the lower main surface 42 of the panel 18 is in close contact with the photosensitive recording surface of the uppermost photosensitive sheet 78 stacked in the film pack 38.
lower. The photosensitive sheet 78 is constantly pressed upward by a pressing spring (not shown) within the pack 38. When ejecting the uppermost photosensitive sheet 78 from the film back 38, the panel moving mechanism 28 is configured to move the panel 18 upwardly by a certain distance under the control of the control circuit 50. . It may be configured such that the liquid crystal panel 18 is always in contact with the surface of the photosensitive sheet 78.

The photosensitive material and the liquid crystal panel 18 may be moved relative to each other while in contact with each other, and the two do not necessarily need to be in close contact with each other during exposure, and there may be a gap of several tens of gm to several hundred gm. The better the parallelism of the exposure rays, the larger the gap may be.

In this way, the liquid crystal panel 18 is in close contact with the image recording surface of the uppermost recording medium 78 at least in the operating state.

Furthermore, the light 34 generated from the light source 12 is incident on the principal surface 4o of the liquid crystal panel 18 as substantially parallel light through an optical system including mirrors 14 and 16. This ensures that a clear image is recorded on the recording medium 78.

By the way, the light source 12 emits white light or visible light 3 close to it.
4 is advantageously used. A single light source may be used, or multiple light sources may be provided to generate white or near-white light. The light source 12, which may be, for example, a light emitting diode, a strobe (xenon lamp), a tank lamp, a fluorescent tube, an electroluminescent device or a plasma discharge tube, is driven by a light source drive circuit 66 under the control of a control circuit 50. be done.

In the optical path 34 immediately in front of the light source 12, a color filter 54 is disposed as shown. The color filter 54 is composed of, for example, three filters that each transmit a different one of the three primary colors RGB. In order to avoid complicating the figure, only one of the three filters is shown. However, these filters 54 are supported by a filter drive mechanism 56, and under the control of a control circuit 50, only one of them selectively moves the optical path 34 from the light source 2.
is configured to be inserted into the by this,
The white light 34 generated from the light source 12 can enter the liquid crystal panel 18 as RGB component light.

The light source 12 may not be configured as such a single light source, but may include three light sources corresponding to each of the three primary color components RGB. For example, the three light sources may be arranged in a triangle and one of the RGB filters may be provided for each. Alternatively, the light source 12 can be used, for example using a light emitting diode or an electroluminescent device.
It may be configured to generate three primary color lights from itself.

In that case, a filter such as the filter 54 and the filter drive mechanism 56 are not necessary, and the light source drive circuit 66 has a function of selectively causing the light sources of these three primary colors to emit light. Furthermore, instead of the additive color method of generating component light, a subtractive color method may be used.

Referring to FIG. 1, the video signal input terminal 46 is connected to a video signal circuit 58. The video signal input to the input terminal 46 may be in the form of a TV signal or an electronic still camera signal, for example. The video signal circuit 58 is a signal processing circuit that converts the input video signal into data of three primary color components RGB. It is. The video signal input to the input terminal 46 may, of course, take the form of three primary color component signals RGB.
In such a case, the video signal circuit 58 is unnecessary.

The output from the video signal circuit 58 is connected to a binarization circuit 82. The binarization circuit 82 binarizes the video signal input from the input terminal 46 using a predetermined threshold as described above. The output from the binarization circuit 82 is connected to the liquid crystal panel drive circuit 44. The drive circuit 44 sequentially drives each pixel cell of the liquid crystal panel 18 in accordance with the binarized data of the three primary color components read out from the binarization circuit 82 .

The control circuit 50 is a functional unit that unifies and controls the operation of the entire device. An operation display section 68 is connected to the control circuit 50, which allows the operator to manually input instructions and to display the status of the apparatus to the operator. In particular, the control circuit 50 performs control to obtain an image with a desired gradation by changing the exposure time or intensity of light that exposes the liquid crystal panel 18.The power supply 76 controls the liquid crystal panel 18, the light source 12, etc. A direct current power source such as a dry battery or a secondary battery that supplies power to the electric circuit elements in the device including the battery.

The operation will be explained.

When the film pack 38 is loaded into the housing 10, the liquid crystal panel 18 is lowered by the panel moving mechanism 28 under the control of the control circuit 50 to the position shown in FIG. As a result, the uppermost photosensitive sheet 78 stacked in the film pack 38 has its recording surface facing the panel 18.
It comes into close contact with the lower main surface 42 of.

Lids 22 and 24 are opened and held in place as shown in FIG. This state is controlled by the switch 70 in the control circuit 5.
Detected at 0.

For example, the output of a video signal source such as an electronic still camera playback device is connected to the video signal input terminal 46. Operation display section 68
When the control circuit 5 is operated to instruct to read the video signal, the control circuit 5
0 controls the video signal circuit 58, the binarization circuit 82, and the threshold value variable circuit 60 by the caps 13, 71, and 72, respectively, and takes in the video signal input to the input terminal 46.

The video signal circuit 58 converts the input video signal into a sufficient format.
For example, it is converted into RGB color component signal data.

When an instruction to print an image is input by operating the operation display unit 68, the control circuit 50 responds to this by first controlling the filter drive mechanism 56 to select a specific color component from the filter 54, for example, the R component. Select filter and light source I2
into the optical path 34 from. At the same time, a control signal is output to the video signal circuit 58 to instruct output of R component data. The R component data output from the video signal circuit 5 is sent to the binarization circuit 82.

The binarization circuit 82 converts 64 thresholds according to, for example, 64 levels of threshold data sent from the variable threshold circuit 58 as described above.
The binarized data of each stage is output sequentially. This data is amplified by the drive circuit 44 and outputted as a drive signal by the drive circuit 44.
LCD panels will be supplied on a daily basis.

As a result, the liquid crystal panel 18 is driven by the binary data of the R component signal and visualizes the black and white image.

In synchronization with driving the liquid crystal panel 18, the control circuit 50 controls the light source drive circuit 66 to emit light 1it12 for a predetermined period. That is, the light is emitted 64 times depending on the number of binarized data. In this way, the exposure using the binarized data is superimposed, and an image of the R color component is recorded on the photosensitive sheet 78 as a latent image.

When the recording of the R color component image is completed, the control circuit 50
For images of the remaining color components, for example, G and B components, the filter 54 is sequentially set to the corresponding color, and the corresponding color component data is read out from the video signal circuit 58 and converted into binary data by the binarization circuit 82. By driving the liquid crystal panel 18 and simultaneously driving the light [12], these images are recorded in an overlapping manner on the same photosensitive sheet 78. The control circuit 50 controls the photosensitive sheet by the light source 12 for each of the RGB component images. By adjusting the exposure time of 8, the color correction of the original image can be performed.

In other words, the color image completed by superimposing exposure on the photosensitive sheet 78 has undergone color correction.

When the recording of the 3N color latent image is completed, the control circuit 50 controls the panel moving mechanism 28 to lift the liquid crystal panel 18 upward by a certain distance, and controls the developing roller drive circuit 52 to drive the developing roller 52. As a result, the recorded photosensitive sheet 78 is smoothly transferred from the film pack 38 to the path 4.
The developer roller 20 develops the image during the feeding. If the photosensitive sheet 78 is for instant photography, the developer is loosely closed during this process and the latent image is developed. In this way, the color image represented by the video signal of the input 48 is visualized on the recording medium 78, and the recording medium 78 is
is ejected through 0.

When not in use, the lids 22 and 24 are folded down, as shown in FIG. 3. The control circuit 50 detects this condition through the switch 70 and stops the entire function of the device.

According to this embodiment, as described above, the binary gradation liquid crystal panel 18 is used, and a multi-gradation image is obtained by performing multiple exposure using data binarized by the binarization circuit. Therefore, it is possible to obtain a hard copy of a multi-gradation image using the binary gradation liquid crystal panel 18 without requiring a multi-gradation liquid crystal panel, so that the liquid crystal panel I8 is easily available.

A simple matrix type may be used instead of an active matrix type, and since it is only necessary to perform processing to binarize the video signal data and output it to the liquid crystal panel 18, a complicated processing circuit is not required.

FIG. 4 shows another embodiment of the printer according to the invention.

The one shown in the figure has a frame memory 62 and two
The 64-step binarized data output from the digitization circuit 82 is temporarily stored in the frame memory 62. The frame memory 62 is a storage circuit that stores binarized RGB component data for one frame. frame memory 6
2 has its reading and writing controlled by a control circuit 50, and its read data output 64 is connected to the liquid crystal panel drive circuit 44.

According to this embodiment, the input and binarized data is stored in the frame memory 62, so that the input video data is stored in the frame memory 62. The signal may be a video.

In the above embodiment, for example, when multiple exposures are performed multiple times using data that has been binarized into 64 levels, the light intensity and exposure time of each of the multiple exposures are uniform; The exposure intensity and exposure time may be made different to adjust the gradation. For example, by changing the scan rate of the R1 value set in the variable threshold circuit 80, it is possible to change the exposure time for each binarized data. Further, the exposure intensity of the light source may be changed by sending a control signal from the control circuit 50 to the light source drive circuit 66 for control.

Further, the binarization level of the liquid crystal panel may be changed one after another while the light source remains lit at a certain intensity.

In the embodiment described above, each pixel data constituting the image is binarized and exposed in a superimposed manner at a position corresponding to the pixel on the recording medium 78. Therefore, as described above, the portion of the liquid crystal panel corresponding to the light blocking area 102 is not exposed, so that, for example, a white image may be underexposed.

In order to prevent this, the position of the liquid crystal panel relative to the recording medium 78 is adjusted so that the light blocking area 102 in FIG. 9 can also be exposed.
Four positions 301, 302, 30 as shown in FIG.
In steps 3 and 304, exposure may be performed using the same pixel data. If you do this, the aperture ratio will be 25%.
Even when a liquid crystal panel of 1 is used, exposure can be performed with an aperture ratio of 100%.

Alternatively, using four adjacent pixel data, four positions 301, 302, 303, 304 as shown in FIG.
Alternatively, the exposure may be performed using In this way, the light blocking area 102 can be exposed, and an image with a large number of pixels can be exposed using a liquid crystal panel with a small number of pixels.

Further, although the above embodiment is a printer housed in a compact housing, the present invention is not limited to a printer housed in such a housing, as long as it is a printer that exposes to light using a liquid crystal panel. . For example, the present invention can be applied to a device that exposes and prints an image displayed on a liquid crystal panel onto a photosensitive material through a lens, such as a printing device that has an enlargement function (enlargement, reduction).

In addition to directly exposing the photosensitive material forming a hard copy through a liquid crystal panel as in the above embodiment,
It can also be applied to those in which recording is performed by exposing a photoconductive material to light and transferring the formed latent image to a recording medium.

In the above explanation, the photosensitive material is sensitive only to the visible wavelength range, but the photosensitive material does not necessarily have to be sensitive only to the visible wavelength range. The photosensitive materials used in the hard copy system of the product name are yellow, red,
They are sensitive to infrared light and emit yellow, magenta, and cyan dyes, respectively. Examples using such photosensitive materials are also included in the present invention.

In each of the embodiments described above, color images are printed using color video signals, but it goes without saying that the present invention can also be applied to printing black and white images. In the case of printing a monochrome image, it is sufficient to send the video signal of the monochrome image from the frame 7 memory 62 to the liquid crystal panel 8, and the filter 54 is not necessary.

Effects As described above, the video printer according to the present invention binarizes video signal data using a predetermined threshold value, obtains a plurality of binarized data by changing the threshold value, and performs multiple gradations by exposing the data multiple times. form an image. Therefore, it is possible to form high-quality images with multiple gradations using a binary gradation liquid crystal panel without using a multi-gradation liquid crystal panel. The device can have a similar configuration.

Furthermore, since exposure is performed using a liquid crystal display panel, the printing time is short and it is easy to make a compact device, and since a mass-produced liquid crystal panel can be used, it is inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing an embodiment of a video printer according to the present invention; Fig. 2 is a side sectional view showing the embodiment in a used state; Fig. 3 is a side sectional view showing the same embodiment in a non-used state. 4 is a functional block diagram showing another embodiment of the video printer according to the present invention; FIGS. 5A and 5B are diagrams showing input and output of the binarization circuit of FIG. 1; FIG. is a diagram showing the relationship between binarized data and image density, Figure 7 is a diagram showing the liquid crystal panel in the blocking state, Figure 8 is a diagram showing the liquid crystal panel in the transmitting state, and Figure 9 is the diagram showing the pixels of the liquid crystal panel. FIG. 10 is a diagram showing the arrangement of regions. FIG. 10 is a diagram showing the order in which the transmissive regions of the liquid crystal panel are moved. 12゜54゜60゜62゜82゜78゜Explanation of symbols of main parts Light source Liquid crystal panel filter Threshold variable circuit Frame memory Binarization circuit Photosensitive sheet Liquid crystal shutter

Claims (1)

[Scope of Claims] 1. A video that receives a video signal representing an image, displays the image as a black and white image on a liquid crystal panel according to the video signal, and records the displayed image as a visible image on a photosensitive recording medium. The printer includes: an input terminal for inputting the video signal; a binarization means for binarizing the multi-gradation video signal input from the input terminal using a predetermined threshold; threshold value variable means for setting the threshold value used in the means to various values; a recording medium accommodating section for accommodating the photosensitive recording medium; a liquid crystal panel; a light source that generates sensitizing light in a wavelength range to which the photosensitive recording medium can be sensitized; an optical system that guides the sensitizing light from the light source to the liquid crystal panel; and binarization by the binarization means. control means for displaying the image on the liquid crystal panel according to the image data and controlling the light source; when the control means receives a video signal at the input terminal;
Controlling the threshold value changing means to change the threshold value used in the binarizing means to a plurality of set values, and causing the binarizing means to output binarized image data for each threshold value. , the operation of sequentially displaying an image on the liquid crystal panel based on the binarized image data, and causing the light source to emit light to expose the image displayed on the liquid crystal panel onto the photosensitive surface of the photosensitive recording medium; A video printer characterized in that the process is performed in accordance with the number of digitized image data to expose a multi-gradation image represented by the video signal onto the photosensitive recording medium. 2. The video printer according to claim 1, wherein the control means changes the threshold value variable output speed and the intensity of the sensitizing light generated from the light source. A video printer characterized in that the means and the light source are controlled for each of the threshold values. 3. The video printer according to claim 1, wherein the input terminal, the recording medium accommodating section, the liquid crystal panel, the light source, and the optical system are housed in a housing, and the liquid crystal panel is in close contact with the photosensitive surface of the photosensitive recording medium. A video printer characterized in that: