JPH06289509A - Photographic printer - Google Patents

Abstract

PURPOSE:To provide a photographic printer capable of accurately and easily correcting density and color in every small area, as to a photographic printer for printing and exposing an image recorded on a photographic film onto a photosensitive material. CONSTITUTION:A diffusion box 14, a 1st polarizing plate 15 and a liquid crystal cell 16 with liquid crystal held between grid-shaped transparent electrodes which are arranged in a matrix on two counter surfaces of the cell are installed between the photographic film 19 and the light source 10, and light is diffused through them so that a frame to be printed on the photographic film 19 may be irradiated with the light, and then, the light transmitted through the photographic film 19 is image-formed on a photographic printing paper 24 through a 2nd polarizing means 21 installed between a printing lens 22, and then, printing and exposure are executed. A half mirror 28 is installed between the photographic film 19 and the 2nd polarizing plate 21, and a sufficient quantity of image light not transmitted through the 2nd polarizing plate 21 but reflected on the half mirror 28 is detected by image sensors 33 and 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printer which prints and exposes a recorded image on a photographic film onto a light-sensitive material, and in particular, enables accurate and easy light control for each small area for density and color correction. Can be related to photo printers.

[0002]

2. Description of the Related Art As an apparatus for printing and exposing a recorded image on a photographic film on a photosensitive material, for example, Japanese Patent Publication No. 52-20.
The device shown in Japanese Patent No. 853 is known. This device is configured to project illumination light onto an image recorded on photographic film and apply different voltages to liquid crystals arranged in the transmission path of the illumination light to control the amount of light imaged on the photosensitive material. There is. Also, Japanese Patent Publication No. 64-10819 discloses a device for illuminating a recorded image on a photographic film and a liquid crystal device in which liquid crystal elements are arranged in a matrix between the photographic film and an electric power applied to each liquid crystal element. An apparatus configured to change the amount of transmitted light by changing a signal to perform printing density correction for forming an image on a photosensitive material, color correction, printing of characters, and the like is shown.

[0003]

However, the Japanese Patent Publication Sho 52
According to the photographic printing apparatus disclosed in Japanese Patent Laid-Open No. 20853, it is difficult to form a sufficiently high-contrast image on a photosensitive material due to a change caused by light scattering of liquid crystal arranged in a transmission light path of a photographic film. There is. In the device disclosed in Japanese Patent Publication No. 64-10819,
Since it is necessary to arrange polarizing plates on the front side and the rear side of the liquid crystal, the light reaching the image sensor provided between the photographic film and the photosensitive material is already a large amount of light when passing through the polarizing plate and the liquid crystal. Have lost. Therefore, it is difficult to detect the image formation of transmitted light due to the sensitivity of the sensor.

In the above-mentioned device, when the light intensity of the illumination light is increased in order to compensate for the loss of light quantity, the light energy that cannot be transmitted by the polarizing plate is accumulated as heat,
There is also a drawback that the liquid crystal temperature rises and the transparency and hue change depending on the temperature characteristics of the liquid crystal. In addition, there is a problem in that the step in the gap between the transparent electrodes provided for each liquid crystal element of the liquid crystal device serves as a mask and is printed on the photosensitive material.

Therefore, the present invention provides a photographic printer which eliminates the above-mentioned drawbacks of the conventional photographic printer device and can accurately and easily perform image density correction, color correction and the like for each small area of a recorded image formed on a photographic film. It is the one we are trying to provide.

[0006]

The above object of the present invention is to provide a light source for illuminating the photographic film, and a light source for illuminating the photographic film in a photographic printer for printing and exposing a recorded image on the photographic film on a photosensitive material. A light diffusing means provided between the light diffusing means for diffusing the illumination light from the light source and striking a frame to be printed on the photographic film; and a first polarizing means provided between the light diffusing means and the photographic film. , A drive signal which is provided between the first polarizing means and the photographic film and is held between the grid-shaped transparent electrodes arranged in a matrix on two opposite surfaces, and which is given to the grid-shaped transparent electrodes corresponding to the correction information. A liquid crystal cell having a liquid crystal compound whose orientation state changes according to the following, a second polarizing means provided between the photographic film and a printing lens, and a second polarizing means between the second polarizing means and the photographic film. An image sensor for detecting the density of a recorded image on a photographic film, and exposure information relating to a correction area and a correction amount of the recorded image is determined from the density distribution of the recorded image on the photographic film detected by the image sensor. And a control means for sending a drive signal to the grid-shaped transparent electrodes for controlling the alignment state of the liquid crystal layer in the region corresponding to.

[0007]

According to the photographic printer of the present invention, the change in the alignment state of each small region of the liquid crystal compound held between the grid-like transparent electrodes arranged in a matrix and the polarization by the two polarizing means whose polarization axes are orthogonal to each other. By the action, the light amount of the image reaching the photosensitive material changes for each small area. for that reason,
On the light-sensitive material on which an image is newly formed, the density correction and the color correction can be controlled for each small area, and the second polarization means is provided separately from the liquid crystal cell, and the light is transmitted through the second polarization means at the position where photometry is performed. Since the light is not transmitted, the image light can be detected in a bright state with little loss of light amount, and accurate photometry can be performed.
Therefore, the photometric means is not required to have high sensitivity.

Further, in order to prevent the photosensitive material from being exposed to external light when the apparatus main body is not used or during the transportation or exchange of the photographic film, the function of the shutter provided in a general photographic printer is By disposing two second polarizing means between the film and the light-sensitive material and making the polarization axes orthogonal (crossed nicols), the second polarizing means can also serve as the second polarizing means. Further, when performing a printing operation, the polarization axes of the two second polarizing means may be used in parallel with each other, and light can be transmitted.

Further, if a light diffusing means is provided between the grid-like transparent electrodes sandwiching the liquid crystal and the photographic film, the steps of the transparent electrodes and the boundaries of the small areas formed by the transparent electrodes become invisible on the reproduced image. For this purpose, the second
The support of the polarizing film of the polarizing means may have a light scattering function.

In order to change the transparency of the liquid crystal for each small region, there are means such as applying an electric field using a TN (Twisted Nematic) type liquid crystal or applying an electric field using a bistable ferroelectric type liquid crystal. . Among these, as a liquid crystal compound that is divided into a matrix by orthogonally intersecting the grid-shaped transparent electrodes and driven simultaneously in each small area, an Active Twisted Nematic liquid crystal in which a thin film semiconductor element is formed in each small area The transmittance threshold is steep, which is preferable. Further, in order to change the color of light transmitted through the liquid crystal, there is a means such as using a nematic liquid crystal to apply an electric field to utilize a birefringence control (ECB) effect.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a photographic printer according to an embodiment. Light projected from a lamp 10 is reflected by a reflector 11 and then passed through a heat insulating filter 12 to pass through Y (yellow), M (magenta), and C ( The light enters the light quality adjusting unit 13 including each color filter (cyan). The light quality adjusting unit 13 is controlled by the controller 18, and the amount of each filter inserted into the optical path can be changed.

A diffusion box 14 is disposed above the light quality adjusting unit 13 and diffuses the light of the lamp 10 whose light quality is adjusted by the light quality adjusting unit 13 through the first polarizing plate 15 and the liquid crystal cell 16. The frame to be printed on the photographic film (eg, negative film) 19 is illuminated. The liquid crystal cell 16 is, for example, a TN (Twist).
ed nematic) type liquid crystal is held and each pixel has a TFT (Thin Film)
It is a TFT type liquid crystal cell equipped with a transistor. The photographic film 19 is set on the film carrier 20,
The film carrier 20 detects the print target frame position and sets the print target frame at a position facing the printing paper 24.

The second polarizing plate 21 has a polarization axis orthogonal to that of the first polarizing plate 15 and is arranged so that the TFT type liquid crystal cell 16 exhibits the maximum contrast. In the conventional liquid crystal display plate, the polarizing plate is integrated with the liquid crystal cell 16, whereas in the configuration of this example, the second polarizing plate 21 is provided separately from the liquid crystal cell 16. The image of the frame to be printed is imaged on the photographic paper 24 set at the printing position by the printing lens 22 via the second polarizing plate 21. A shutter 25 is arranged between the printing lens 22 and the printing paper 24, and the shutter 25 is opened and closed by a shutter drive unit 26.

A half mirror 28 is disposed on the printing optical axis between the film carrier 20 and the second polarizing plate 21, and splits the printing light into a photometric / monitor system 30. The branched light passes through the lens 31 and the half mirror 32,
An image is formed on the image sensor 33 for simulation and the image sensor 34 for photometry. Each image sensor 33, 3
Since the light to 4 is the light before reaching the second polarizing plate 21,
There is no light amount loss due to the second polarizing plate 21, and it is possible to carry out photometry and monitoring with a sufficient light amount. This allows
It enables accurate photometry and monitoring.

The image sensor 33 for simulation is
A negative image of the frame to be printed is picked up, and this video signal is sent to the monitor image processing section 36. As is well known, the monitor image processing unit 36 performs A / D conversion, negative-positive conversion, gradation correction,
The monitor image simulating the finished print is displayed on the color CRT 37 by performing the saturation correction and the like. The saturation correction not only corrects the difference between the spectral sensitivity of the photographic printing paper 24 and the spectral sensitivity of the image sensor 33, but also performs color correction for displaying an image that simulates this correction when inputting correction data. Correction data is input to the controller (control unit)
The density correction data and the color correction data, which are input by operating the keyboard 40 connected to the display 18, are displayed on the display 41 and the image processing unit 3
Sent to 6.

The photometric image sensor 34 performs three-color separated photometry on each point of the frame to be printed. This photometric signal is sent to the characteristic value calculator 45. The characteristic value calculation unit 45 uses the LATD
And various other characteristic values are calculated, and these are calculated as the exposure amount calculation unit 4
Send to 6. The exposure amount calculation unit 46 calculates the exposure amount for each color using a well-known exposure amount calculation formula, and sends this to the controller 18. In this exposure amount calculation, correction data input from the keyboard 40 is also used as needed.

The controller 18 converts the exposure amount for each color into an exposure time, and outputs a drive control signal to the liquid crystal controller 23 and the light quality adjusting section 13 based on this. The liquid crystal controller 23 generates a drive signal for driving the liquid crystal cell 16 at a predetermined density by the drive control signal, and sets a predetermined pixel of the liquid crystal cell 16 to a predetermined light transmission amount. Further, the light quality adjusting unit 13 inserts the Y, M, and C filters into the optical path according to the drive control signal from the controller 18. Further, the controller 18 drives the liquid crystal controller 23,
The shutter 25 is opened for a certain period of time via the shutter drive unit 26, and the image of the frame to be printed on the photographic film 19 is printed and exposed on the photographic paper 24. Note that the relationship between the exposure amount and the drive signal to the liquid crystal cell 16 has been previously obtained by experiments or the like, and the conversion table for this is stored in the memory in the controller 18.

When changing the gradation of the image to be exposed, the degree is detected by the photometric value of the photometric image sensor 34, and the light transmittance of each corresponding pixel is set by a preset amount according to the degree. Change the gradation. In the measurement of the image density distribution of the photographic film 19 by the photometric image sensor 34, in the case of a negative film, the density is considerably low in a portion where the image density is considerably low, and the gradation cannot be expressed by exposing as it is. Sometimes. For example, in a landscape photograph under natural sunlight, shaded areas are uniformly darkened, and it is difficult to reproduce good gradation.

As shown by the characteristic curve a of the negative film and the characteristic curve b of the photographic paper in FIG. 2, the range of density change D2 with respect to the range of change b of the exposure amount of the photographic paper is the exposure amount of an ordinary negative film (subject It is narrower than the density change range D1 with respect to the brightness change range a1. For this reason, when exposure is performed with light intensity such that the vicinity of the center of the photosensitive area of the printing paper and the vicinity of the center of the recorded image density of the photographic film match as in the conventional case
The previously selected portion a3 having a considerably high density (or the portion a2 having a very low density) is white (or black) on the photographic paper and the image is crushed and the gradation characteristic is lost. When such an image of the photographic film 19 is detected by the image sensor, the second polarizing plate 21 is inserted between the optical paths of the photographic film 19 and the printing lens 22 so as not to block the optical path to the image sensor. The polarization plane of the two polarization plates 21 is arranged so as to be orthogonal to the polarization plane of the first polarization plate 15.

In this state, the liquid crystal drive signal is controlled so that the transmittance becomes low when the liquid crystal cell 16 corresponding to the portion a2 on the photographic film 19 where the image density is considerably low passes through the two polarizing plates 15 and 21. . Then, in FIG. 2, exposure is performed under the same conditions as when the negative density (exposure amount) is increased from E4 to E3. Photo film 19 in this state
It was confirmed by the image sensor 33 that the amount of light radiated on the photographic film 19 sufficiently exhibits the gradation characteristics corresponding to the high image density portion on the photographic film 19. In this way, when the recorded image of the photographic film 19 was copied on the photographic paper 24, it was confirmed that the portion of the photographic film 19 having a low density was not crushed in black and good printing exposure was possible.

Similarly, when the liquid crystal drive signal is controlled so that the transmittance is high even in the portion a3 where the image density is considerably high, the negative density (exposure amount) is E1 in FIG.
Exposure is performed under the same conditions as when the image density is decreased from E2 to E2, and the gradation characteristics can be sufficiently exhibited even in the portion a3 having a high image density. Further, the phenomenon of copying the step of the transparent electrode, which was observed when the second polarizing plate was placed between the transparent electrode and the photographic film that sandwich the liquid crystal cell, disappeared.

In the above embodiment, the number of the second polarizing plate 21 is one, but it is possible to install the two second polarizing plates 21 and make them function as a shutter, and to omit the shutter 25 instead. When the two second polarizing plates 21 are arranged with their polarization axes orthogonal to each other, the photographic paper 24 is shielded from light, and conversely, when the two polarizing plates are arranged so that their polarization axes are parallel, the light reaches the photographic paper 24. Such an operation can be obtained by arranging the second polarizing plate 21 on the photographic paper 24 side so as to be rotatable in a plane orthogonal to the plane of the paper so that the polarization axis can be changed. Further, by providing the second polarizing plate 21 in the vicinity of or integrally with the printing lens 22, the polarizing film can be made small and inexpensive, and the long-term reliability can be improved. Further, the second polarizing plate 21 and the baking lens 22
If the two are integrated, the switching operation of whether or not to perform light control for each small area of the image can be performed by moving the printing lens, and the degree of freedom in the configuration increases.

[0023]

According to the photographic printer of the present invention,
Since the light before reaching the second polarization means is read by the image sensor to perform photometry and the like, the structure is simple,
The image light transmitted through the photographic film can be read with a larger amount of light than in the past, the photometry is facilitated and the reliability is improved, and the photometry means is not required to have high sensitivity. Further, since the frame to be printed of the photographic film is irradiated through the light diffusing means, a gap between the matrix-shaped transparent electrodes provided in the liquid crystal cell or a step is not printed at the same time as the printed image. Furthermore, since the liquid crystal held between the transparent grid electrodes arranged in a matrix between the light source and the photographic film is arranged and the transmittance can be controlled for each small region by passing through the two polarizing means in front and rear, it is possible to control the transmittance for each small region. Density correction, color correction, etc. can be accurately and easily performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a photographic printer according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a characteristic curve of a negative film and a characteristic curve of photographic paper.

[Explanation of symbols]

 10 Light Source 13 Light Quality Control Section 14 Diffusion Box 15 First Polarizing Plate 16 Liquid Crystal Cell 18 Controller 19 Photographic Film 21 Second Polarizing Plate 22 Printing Lens 23 Liquid Crystal Controller 24 Printing Paper 28 Half Mirror

Claims (1)

[Claims] 1. A photographic printer which prints and exposes a recorded image on a photographic film on a photosensitive material, wherein a light source for illuminating the photographic film, and an illumination light from the light source is provided between the light source and the photographic film. A light diffusing means for diffusing the light onto a frame to be printed on the photographic film; a first polarizing means provided between the light diffusing means and the photographic film; and a first polarizing means and the photographic film. Provided between
A liquid crystal cell comprising a liquid crystal compound which is held between lattice-shaped transparent electrodes arranged in a matrix on two opposite surfaces and whose alignment state is changed according to a drive signal given to the lattice-shaped transparent electrodes corresponding to correction information; The second provided between the film and the printing lens
A polarizing means, an image sensor for detecting a recorded image density on the photographic film between the second polarizing means and the photographic film, and a density distribution of a recorded image on the photographic film detected by the image sensor And a control means for determining a correction area of the recorded image and exposure information relating to the correction amount, and sending a drive signal to the grid transparent electrodes for controlling the alignment state of the liquid crystal layer in the area corresponding to this information. Photo printer to do.