JP3032928B2 - Photo printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printer for printing a recorded image on a photographic film onto a photosensitive material, and more particularly, to accurately and easily perform light control for each small area for density and color correction. Regarding a photo printer that can.

[0002]

2. Description of the Related Art As an apparatus for printing and exposing a recorded image on a photographic film onto a photosensitive material, for example, JP-B-52-20
An apparatus disclosed in Japanese Patent Publication No. 853 is known. This apparatus is configured to project illumination light onto an image recorded on a photographic film, apply different voltages to liquid crystals arranged in a transmission optical path of the illumination light, and control the amount of light formed on a photosensitive material. I have. 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 device applied to each liquid crystal element. An apparatus is shown in which the amount of transmitted light is changed by changing a signal to perform printing density correction, color correction, printing of characters, and the like for forming an image on a photosensitive material.

[0003]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. Sho 52
According to the photographic printing apparatus disclosed in JP-A-20853, it is difficult to form an image having a sufficiently high contrast on a photosensitive material due to a change based on light scattering of a liquid crystal disposed in a transmission optical 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 and back sides of the liquid crystal, light reaching the image sensor provided between the photographic film and the photosensitive material already has a large amount of light when passing through the polarizing plate and the liquid crystal. Have lost. Therefore, there is a problem that it is difficult to detect an image of transmitted light because of the sensitivity of the sensor.

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

Therefore, the present invention eliminates the above-mentioned drawbacks of the conventional photographic printer device, and provides a photographic printer capable of accurately and easily performing image density correction and color correction for each small area of a recorded image formed on a photographic film. It is something to offer.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a photographic printer for printing and exposing a recorded image on a photographic film to a photosensitive material, comprising: a light source for illuminating the photographic film; A light diffusing unit provided between the light diffusing unit and the illumination light from the light source to irradiate a frame to be printed on the photographic film; and a first polarizing unit provided between the light diffusing unit and the photographic film. A driving signal provided between the first polarizing means and the photographic film and held between lattice-shaped transparent electrodes arranged in a matrix on two opposing surfaces, and applied to the lattice-shaped transparent electrode in accordance with correction information A liquid crystal cell having a liquid crystal compound whose alignment state changes according to the following, a second polarizing means provided between the photographic film and the printing lens, and a liquid crystal cell 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 a density distribution of the recorded image on the photographic film detected by the image sensor. And control means for sending a drive signal to the grid-like transparent electrode for controlling the alignment state of the liquid crystal layer in a region corresponding to the above.

[0007]

According to the photographic printer of the present invention, the change in the alignment state of the liquid crystal compound held between the grid-shaped transparent electrodes arranged in a matrix for each small region and the polarization by two polarization 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 a photosensitive material for newly forming an image, density correction and color correction can be controlled for each small area, and the second polarizing means is provided separately from the liquid crystal cell, and the light is supplied to the second polarizing 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.

In order to prevent the photosensitive material from being exposed to external light when the apparatus main body is not used, or when the photographic film is being conveyed or exchanged, the function of a shutter provided in an ordinary photographic printer is described. By arranging two second polarizing means between the film and the photosensitive 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 polarization means may be used in parallel with each other, so that light can be transmitted.

Further, if a light diffusing means is provided between the grid-shaped transparent electrode sandwiching the liquid crystal and the photographic film, the step of the transparent electrode and the boundary of the small area formed by the transparent electrode 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 area, there is a means such as applying an electric field using a TN (Twisted Nematic) type liquid crystal or applying an electric field using a bistable ferroelectric liquid crystal. . Among these, the active twisted nematic liquid crystal, in which thin-film semiconductor elements are formed in each of the small regions, is used as the liquid crystal compound that is divided into a matrix by the grid-shaped transparent electrodes crossing at right angles and driven simultaneously with each of the small regions. The threshold value of the transmittance is steep, which is preferable. In order to change the color of light transmitted through the liquid crystal, there is a method of using a nematic liquid crystal and applying an electric field to use 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, in which light projected from a lamp 10 is reflected by a reflector 11 and then passes through a heat insulating filter 12 to Y (yellow), M (magenta), and C ( (Cyan) is incident on the light quality control unit 13 provided with each color filter. The light quality adjusting unit 13 is controlled by the controller 18 to change the amount of each filter inserted into the optical path.

A diffusion box 14 is disposed above the light quality control unit 13, and diffuses the light of the lamp 10 whose light quality has been controlled by the light quality control unit 13, through the first polarizing plate 15 and the liquid crystal cell 16. To illuminate a frame to be printed on a photographic film (eg, a negative film) 19. The liquid crystal cell 16 is, for example, a TN (Twist
ed Nematic) type liquid crystal and each pixel has a TFT (Thin Film).
Transistor). The photographic film 19 is set on a film carrier 20,
The film carrier 20 detects the position of the frame to be printed and sets the frame to be printed to a position facing the photographic paper 24.

The second polarizing plate 21 is arranged such that the polarizing axis is orthogonal to the first polarizing plate 15 and 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 the present example, the second polarizing plate 21 is provided separately from the liquid crystal cell 16. The image of the frame to be printed is formed 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 disposed between the printing lens 22 and the printing paper 24, and the shutter 25 is opened and closed by a shutter driving unit 26.

A half mirror 28 is arranged on a printing optical axis between the film carrier 20 and the second polarizing plate 21, and branches printing light to a photometry / monitor system 30. The split light passes through a lens 31 and a 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 light to 4 is light before reaching the second polarizer 21,
There is no light quantity loss due to the second polarizing plate 21, and photometry and monitoring with a sufficient light quantity can be performed. This allows
Accurate photometry and monitoring become possible.

The image sensor 33 for simulation is
A negative image of the frame to be printed is captured, and this video signal is sent to the monitor image processing unit 36. As is well known, the monitor image processing unit 36 performs A / D conversion, negative-positive conversion, gradation correction,
A monitor image simulating the finished print is displayed on the color CRT 37 by performing saturation correction and the like. The saturation correction corrects the difference between the spectral sensitivity of the photographic paper 24 and the spectral sensitivity of the image sensor 33, and also performs color correction for displaying an image simulating this correction when correction data is input. The correction data is input to the controller (control unit)
The operation is performed by operating a keyboard 40 connected to the display unit 18, and the input density correction data and color correction data are displayed on the display 41 and the image processing unit 3.
Sent to 6.

The photometric image sensor 34 performs three-color separation photometry on each point of the frame to be printed. This photometric signal is sent to the characteristic value calculator 45. The characteristic value calculator 45 calculates LATD
And various other characteristic values, which are calculated by the
Send to 6. The exposure calculator 46 calculates the exposure for each color by using a well-known exposure calculation formula, and sends it to the controller 18. In the calculation of the exposure amount, correction data input from the keyboard 40 is 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 the converted exposure amount. The liquid crystal controller 23 generates a drive signal for driving the liquid crystal cell 16 at a predetermined density according to the drive control signal, and sets a predetermined pixel of the liquid crystal cell 16 to a predetermined light transmission amount. In addition, the light quality adjusting unit 13 inserts each of the Y, M, and C filters into the optical path according to the drive control signal from the controller 18. Further, the controller 18 operates when the liquid crystal controller 23 is driven.
The shutter 25 is opened for a predetermined 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 is determined in advance by experiments or the like, and a conversion table of the relationship is stored in a 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 pixel corresponding to a predetermined amount is set according to the degree. To 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 portion having a considerably low image density is uniformly reduced in density and cannot express gradation when exposed as it is. Sometimes. For example, in a landscape photograph under natural sunlight, shaded portions are uniformly reproduced dark, and it is difficult to reproduce gradations well.

As shown in FIG. 2 showing the characteristic curve a of the negative film and the characteristic curve b of the photographic paper, the change range D2 of the density with respect to the change range b1 of the exposure amount of the photographic paper is the same as that of the normal negative film. The brightness change range a1 is narrower than the density change range D1. Therefore, when light is exposed at a light intensity where the vicinity of the center of the photosensitive area of the photographic paper and the vicinity of the center of the recorded image density of the photographic film match, as in the related art,
The previously selected portion a3 having a very high density (or portion a2 having a very low density) is white (or black) on a photographic paper, and the image is crushed, and the gradation characteristics are 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 photographic film 19 and the printing lens 22 so as not to block the optical path to the image sensor. The polarizing plane of the two polarizing plates 21 is arranged so as to be orthogonal to the polarizing plane of the first polarizing plate 15.

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

Similarly, when the liquid crystal drive signal is controlled so that the transmittance is increased also in the portion a3 where the image density is considerably high, the negative density (exposure amount) in FIG.
Exposure is performed under the same conditions as when the image density has decreased from E2 to E2, and the gradation characteristics can be sufficiently exhibited even in the portion a3 where the image density is high. Further, the phenomenon that the step of the transparent electrode was copied when the second polarizing plate was inserted between the transparent electrode sandwiching the liquid crystal cell and the photographic film was also eliminated.

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

[0023]

According to the photographic printer of the present invention,
Since the light before reaching the second polarizing means is read by an image sensor to perform photometry and the like, it has a simple configuration,
The image light transmitted through the photographic film can be read with a larger amount of light than before, photometry and the like are facilitated and reliability is improved, and high sensitivity is not required for the photometric means. Further, since the frame to be printed on the photographic film is irradiated through the light diffusing means, gaps and steps between the matrix-shaped transparent electrodes provided in the liquid crystal cell are not printed simultaneously with the printed image. Furthermore, 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 area by passing through two polarizing means before and after. Density correction, color correction, and the like can be performed accurately and easily.

[Brief description of the 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]

 DESCRIPTION OF SYMBOLS 10 Light source 13 Light quality control part 14 Diffusion box 15 1st polarizing plate 16 Liquid crystal cell 18 Controller 19 Photographic film 21 2nd polarizing plate 22 Printing lens 23 Liquid crystal controller 24 Printing paper 28 Half mirror

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03B 27/72-27/80 G03B 27/32 G03B 27/46 G02F 1/13

Claims (1)

(57) [Claims] 1. A photographic printer for printing and exposing a recorded image on a photographic film to a photosensitive material, comprising: a light source for illuminating the photographic film; and a light source provided between the light source and the photographic film; A light diffusing unit that diffuses and strikes a frame to be printed on the photographic film; a first polarizing unit provided between the light diffusing unit and the photographic film; Provided in between,
A liquid crystal cell comprising a liquid crystal compound which is held between lattice-shaped transparent electrodes arranged in a matrix on two opposing surfaces and whose orientation changes according to a drive signal given to the lattice-shaped transparent electrode in accordance with correction information; The second provided between the film and the printing lens
Polarizing means; an image sensor for detecting a density of a recorded image 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 control means for determining a correction area and a correction amount of the recorded image from the exposure information, and sending a drive signal to the lattice-shaped transparent electrode for controlling the alignment state of the liquid crystal layer in the area corresponding to this information. Photo printer.