JPS6032679A - Printer using liquid crystal - Google Patents

Abstract

PURPOSE:To obtain the titled printer capable of obtaining an image having high resolving power and a high contrast ratio, by using a spot light source as an exposure source, and arranging a liquid crystal panel to the photosensitive surface of a photosensitive material in a closely contacted state. CONSTITUTION:A spot light source 2 is used as an exposure source and a scattered light component is removed by a simple iris 5 while a liquid crystal panel 9 is arranged to a color photosensitive material 3 in a closely contacted state. Even if exposure light passes the thick liquid crystal panel 9, a print image does not become obscure. A signal carrying image information is inputted to an image processing circuit 30 to calculate image density and RGB information in each picture element unit of the liquid crystal panel 9 to store the same in RAM31. The rotary position of a RGB filter subjected to rotary driving is deteced by an encoder 32 to be inputted to a synchronous control circuit 33 and a liquid crystal driving circuit 34 performs the linear successive scanning driving of the matrix type liquid crystal panel 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer using a liquid crystal that reproduces an image using a liquid crystal panel driven based on image information and records the image on a photosensitive material.

For example, as shown in Japanese Unexamined Patent Publication No. 57-160667, a liquid crystal panel consisting of many sets of transparent electrodes is arranged on the surface of a photosensitive material that is irradiated with exposure light, and the liquid crystal panel is used to provide image information. A printer is being considered that reproduces the entire image on the panel by being driven by a signal that carries the image, and records the transmitted image of this image by exposing it to the photosensitive material using the exposure light. Printers using liquid crystals have a light-transmissive support such as an optical fiber plate between the liquid crystal panel and the photosensitive material, so optical crosstalk occurs between the individual optical fibers of the optical fiber plate, resulting in the recorded image being distorted. There is also the problem that the contrast ratio of the optical fiber is lowered and the image is blurred, and that the contrast ratio is lowered when the exposure light is incident on the optical fiber obliquely. For liquid crystals with a lower contrast ratio than the original,
Adding factors that further reduce the contrast ratio are:
This is extremely disadvantageous in obtaining recorded images with good gradation. Although it is impossible to impart ideal vertical light selectivity to an optical fiber plate, such an optical fiber plate is not only expensive but also reduces the amount of light reaching the photosensitive material, making it impractical for practical use. Not on point.

On the other hand, as shown in Japanese Patent Application Laid-open No. 55-98721,
A printer using a light source that projects a linear light beam as an exposure source has been considered, but while such an exposure source can provide a sufficient amount of light, the exposure light is scattered, resulting in a decrease in resolution and contrast ratio. It has been considered to use, for example, a reflector with an elliptical cross section or a cell lens to improve the image quality, but this would inevitably result in an increase in the size of the apparatus.

The present invention has been made in view of the above-mentioned circumstances, and its overall purpose is to provide a printer using a liquid crystal that can produce images with high resolution and high contrast ratio, and can be formed inexpensively and compactly. The printer using the liquid crystal of the present invention uses a point light source as the exposure source in the printer using the liquid crystal panel as described above, and, if necessary, reduces the scattered stray light component of the exposure light from the point light source. The present invention is characterized in that it is provided with an aperture that removes the light and brings the point light source closer to an ideal point light source, and is furthermore disposed closely to the photosensitive surface of the entire photosensitive material of the liquid crystal panel.

In the printer of the present invention having the above-mentioned configuration, since a light-transmitting support such as the optical fiber plate described above is used, the problems of optical crosstalk and reduction in contrast ratio due to obliquely incident light naturally do not occur. And since no complicated means are used to make the exposure light into fully parallel light, the device is small.
It can be formed inexpensively (the aperture is simply formed from one plate member, so it is inexpensive and does not require a large installation space). Even if a liquid crystal panel with a certain thickness is exposed with a point light source instead of using parallel light as described above, in the printer of the present invention, since the liquid crystal panel is placed closely to the entire photosensitive material, the image will not be blurred. does not occur. Note that the amount of light for exposure is reduced by narrowing down the exposure light from the point light source with an aperture, but this reduction in the amount of light can be compensated for by using a highly sensitive silver salt photosensitive material as the photosensitive material.

Hereinafter, embodiments of the present invention will be described in detail with reference to all the drawings.

FIG. 1 shows a printer using a liquid crystal according to an embodiment of the present invention. The printer 1 of this embodiment forms color prints by a three-color separation method, for example, and includes a point light source 2 such as a halogen lamp or a xenon flash, and a color sensitive material 3 to which exposure light is irradiated by the point light source 2.
An RGB filter 4 that is rotationally driven by a drive device (not shown) is disposed between the two. A diaphragm 5 is provided in front of the point light source 2 to remove the diffused light component of the exposure light from the point light source 2 through a pinhole 5a to make the point light source 2 close to an ideal point light source. A correction filter 6 for color correction of exposure light is disposed between the aperture 5 and the RGB filter 4.

The color photosensitive material 3 is made of a highly sensitive silver salt photosensitive material, and is supported on a conveyor belt 8 rotated by a drive roll 7, and is conveyed in the direction indicated by the arrow in the figure.

A liquid crystal panel 9 is disposed above the conveyor belt 8 so as to be in close contact with the color photosensitive material 3 on the conveyor belt 8 .

The liquid crystal panel 9 is of a known so-called matrix type, and will be briefly described below. The liquid crystal panel 9 has an upper glass panel 1 disposed facing each other, as shown in the side cross-sectional shape in FIG.
0 and a large number of transparent horizontal electrodes 12 and vertical electrodes 13 arranged in array on the inner surface of the lower glass 11. and these horizontal electrodes 1
Alignment films], 4, and I5 for aligning nematic liquid crystal molecules in one direction are formed on the surfaces of the vertical electrodes J3 and J3. The horizontal electrode 12 and the vertical electrode 13 are arranged in directions perpendicular to each other, as shown in FIG. the above alignment film],
4 and 15 are arranged opposite to each other with a gap between them with a sealing material 16 disposed around the periphery, and a twisted nematic liquid crystal 17 is sealed in this gap. the above alignment film], 4. , 15, the molecular orientation direction of the liquid crystal 17 is determined by the horizontal electrodes 12., 15. Relatively 90 on the surface of the vertical electrode 13
° It is shifted. Further, on the outside of the upper glass 10, a polarizing plate 18 whose polarization axis is aligned with the alignment direction of liquid crystal molecules on the surface of the horizontal electrode 12 is arranged, while on the outside of the lower glass 11, a metal mask 19. A polarizing plate 21 is arranged with a filter 20 in between. The polarizing axis of this polarizing plate 21 is aligned with the polarizing axis of the polarizing plate 18. The above structure is the printed circuit board 22
supported by the horizontal electrode 12. A voltage is applied between the vertical electrodes 13 via a conductive rubber connector 23.

In the liquid crystal panel 9, if no voltage is applied between the electrodes], 2, and 13, the light passing through the polarizing plate 18 becomes linearly polarized light and enters the liquid crystal 170 layer, and the polarizing plane gold 90 follows the molecular orientation of the liquid crystal 17. Rotated by 900 degrees and reaches the polarizing plate 21 - As mentioned above, the polarizing axes of this polarizing plate 21 and the upper polarizing plate 18 are aligned, so the light that reaches the polarizing plate 2J after rotating the polarizing plane by 900 degrees is It is blocked by the polarizing plate 21.

On the other hand, when a voltage exceeding the threshold value to some extent is applied between the electrodes 12 and 13, the liquid crystal 170 molecules change direction by 900 degrees between the two electrodes 12 and 13 due to the electric field effect3.Therefore, the light that has passed through the upper polarizing plate 18i becomes polarized. The light reaches the lower polarizing plate 21 without changing its plane, and passes through the polarizing plate 21. Furthermore, in the region slightly exceeding the above-mentioned threshold Shinkin Bank, the amount of orientation rotation of the molecules of the liquid crystal J7 (that is, the light transmittance of the liquid crystal 17) changes linearly with respect to the applied voltage, so that the electrodes 1.2, 1
By changing the voltage applied to the polarizing plate 3, the light transmittance from the polarizing plate 8 to the polarizing plate 21 can be completely controlled. In such a matrix type liquid crystal panel 9, horizontal electrodes 12. By selecting all of the vertical electrodes 13 to which voltage is to be applied, the bright areas (light-transmitting areas) and dark areas (light-opaque areas) can be set for each opposing portion of both electrodes 12 and 13 as desired. The entire image can be formed. That is, the opposing portion of the electrodes 12 and 13 constitutes one pixel 9a (see Figure 3), but by changing the voltage value applied to the selected electrodes i2 and 13, the brightness of this pixel 9a can be changed. You can obtain halftones by

FIG. 4 is a block diagram of a circuit for controlling the apparatus shown in FIG. 1.The operation of the printer l of this embodiment will be explained below with reference to FIG. A signal carrying image information is input to an image processing circuit 30, and the image processing circuit 30
The image density and RGB information (red, green, blue information) are calculated for each pixel of the liquid crystal panel 9 in units of 98.

= 8- The image signal SO carrying these image density and RGB information is RA, M (Random A, access Mem
ory) 3-way rotationally driven RGB stored in 31
The rotational position of the filter 4 is detected by the encoder 32, and the filter position signal 5IFi of the encoder 32,
, 0 is input to the synchronization control circuit 33. The liquid crystal drive circuit 34 is a known one that drives a matrix type liquid crystal panel in a so-called line sequential scan.
The voltage application state is sequentially selected at a predetermined timing, and the image signal SO corresponding to each pixel 9a constituted by the selected horizontal electrode 12 is sent from the RAM 31 by a timing signal S2 synchronized with this timing.

Full readout, selectively setting a large number of vertical electrodes 13 to a voltage application state based on image density information of the image signal SO'',
Each pixel 9ai constituted by the selected horizontal electrode 12 is set to a desired brightness/darkness state. The above operation is sequentially repeated over all horizontal electrodes 12. A drive signal S4 is input to the liquid crystal panel 9, and the brightness/darkness is set in units of pixels 9a. An image with the settings is reproduced on the liquid crystal panel 9. At this time, the brightness of each pixel 9a can be changed by changing the voltage value applied to each vertical electrode 13 based on the image density information.

As described above, all bright and dark areas are set on the liquid crystal panel 9 to form a grayscale image, and the synchronization signal S4f is inputted from the synchronization control circuit 33 to the liquid crystal drive circuit 34, and each color filter of the RGB filter 4 is controlled by the exposure system. By controlling the timing of the bright state selection of each pixel 9a and the timing of selecting the bright state of each pixel 9a based on the RGB information of the image signal SO", the light transmitted through each pixel 9a (i7) is set to a desired hue. .

The color sensitive material 3 is irradiated with exposure light through the liquid crystal panel 9 driven as described above, and a transmitted image of the image is formed by forming hue and shade in units of each pixel 9a in the liquid crystal panel 9. exposed to light. Therefore, when the line sequential scanning of the matrix type liquid crystal panel 9 is completed, the drive signal 5li is sent from the synchronization side one circuit 33 to the drive roll 7.
f: Output, rotate the conveyor belt 8, and take out the color photosensitive material 3 from the exposure system.

When a color photosensitive material 3 that requires normal development processing is used, the color photosensitive material 3 can be completely automatically supplied to the developing unit by the conveyor belt 8. As the shredded color photosensitive material 3, a self-processing film unit,
It is also possible to use a so-called instant photographic film, and in such a case, a normal developing unit is not provided, and a print is obtained immediately by passing the film through a processing liquid developing roll. Since a point light source 2 is used and no complicated means for converting the exposure light into parallel light is required, the printer 1 has an extremely simple structure, is small in size,
It can be formed at low cost. In addition, by using a simple aperture 5, the point light source 2 becomes close to an ideal point light source, and in addition, since the liquid crystal panel 9 is placed closely to the color sensitive material 3, the exposure light can be distributed over a certain amount of thickness. The printed image is not blurred even though it passes through a liquid crystal panel 9 that has a certain color.

Furthermore, in this printer 1, as mentioned above, since an optical fiber plate or the like is not used as a light-transmitting support, it is natural that the contrast ratio decreases and the image becomes blurred due to optical crosstalk as mentioned above. Does not occur.

In the printer 1 of the above embodiment, a matrix type liquid crystal panel 9 is used, but a long and narrow so-called array type liquid crystal panel using only one vertical electrode is used as the liquid crystal panel. The main scanning is obtained by driving the RGB
The color sensitive material 3 may be obtained by feeding the color sensitive material 3 in a direction perpendicular to the vertical electrodes by feeding the conveyor belt 8 all steps in synchronization with the filter 4.

Further, although the printer 1 of the above embodiment is for obtaining a color print, it is of course possible to form a monochromatic shading image without providing a means for forming a color image. However, as mentioned above, the printer using the liquid crystal of the present invention has an extremely simple structure and is compact, so if it is formed as a color printer that requires an RGB filter and its driving device, it will be possible to miniaturize the device. The advantage of being able to do so is especially taken advantage of.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a printer according to an embodiment of the present invention; FIG. 2 is a side sectional view of a liquid crystal panel used in the printer; FIG. 3 is a plan view showing transparent electrodes of the liquid crystal panel; Figure 4 is a block diagram showing the control circuitry of the printer mentioned above. ■...Printer 2...
...Point Light source 3...Color photosensitive material Aperture 9...LCD panel 12...Horizontal Electrode 13...Vertical
Electrode 34...Liquid crystal drive circuit L...
...Exposure light SO... Image signal -15 = Fig. 1 Fig. 2

Claims (1)

[Claims] A point light source that projects exposure light toward the photosensitive material; a liquid crystal panel that includes multiple sets of transparent electrodes arranged in close contact with the photosensitive surface of the photosensitive material to control transmission of the exposure light; and image information. A printer using a liquid crystal driven by a liquid crystal drive circuit that controls voltage application to each of the electrodes using signals carrying the voltage.